Abstract: Human milk oligosaccharides （HMOs） are a group of complex glycans in human milk and play an important role in promoting the growth and development of infants, and more than 200 kinds of HMOs have been identified so far. In this paper, the types and structures of HMOs and their roles in improving infant intestinal health, promoting immune system development and brain development were reviewed. The application status of HMOs was summarized, the possibility and necessity of industrial production and application of HMOs in the future were prospected.
Abstract: Microfluidic chips are driven by microfluidic pumps and controlled by microfluidic valves in microfluidic systems to achieve accurate manipulation of microfluidics. With the continuous improvement of microfluidic chip integration, liquid channels have become more complex and have smaller volumes. How to achieve fluid drive and control at the micro scale has become a key focus in chip design. The paper elaborates on the current research status, key technologies, and development trends of micro pumps and micro valves both domestically and internationally, aiming to provide reference and guidance for the development of related industries and technological research.
Abstract: Objective: To find, prepare and identify a new oxyphenisatine di（acetate） analogue. Methods: A suspected derivative of oxyphenisatine di（acetate） was found by high-performance liquid chromatography-quadrupole-time-of-flight-mass spectrometry during the routine screening of weight loss healthcare product. The compound was isolated and purified by column chromatography, and the possible structures were inferred from the information of isotope mass spectra, secondary ion mass spectra, one-dimensional and two-dimensional NMR spectra. Finally, all possible structures were prepared by de novo synthesis strategy, and their fine structures were confirmed by spectral comparison. Results： The compound was identified as 5-Cl oxyphenisatine di（acetate）, a new type of oxyphenisatine di（acetate）, which has not been approved as food additives. Conclusion: The toxicological and pharmacological effects of this compound are not clear and should be of concern to regulators. The mass spectrometric fragmentation rule and the de novo synthesis of doubtful structures of these compounds will be beneficial to confirm the fine structure of new compounds.
Abstract: Objective: This study aimed to explore the optimal medium composition and culture conditions for obtaining the maximum viable count of Brevibacillus laterosporus. Methods: Based on establishing the correlation regression equation between the MTT colorimetric method and plate counting method, the optimal medium composition (carbon source, nitrogen source, inorganic salt) and fermentation conditions (initial pH, temperature, inoculation amount, KH2PO4) for obtaining the maximum viable count of B. laterosporus were optimized. Results: A significant linear correlation for viable count determination between MTT colorimetry and plate counting (R2>0.999) was found; Maltose, CaCl2, initial pH and KH2PO4 were the significant factors. The optimal fermentation condition was 8.75 g/L maltose, 0.17 g/L CaCl2, 7.07 initial pH and 3.73 g/L KH2PO4. Under the control of these conditions, the number of viable counts was 8.12×108 CFU/mL. However, no significant difference from the theoretical number (8.25×108 CFU/mL) was found. Conclusion: Based on MTT colorimetry and response surface methodology, the culture conditions for the maximum viable count of B. laterosporus were optimized and the number of viable counts was higher than before optimization increased by 3.02 times.
Abstract: Objective: This study focused on investigating the enzymatic characteristics of D-lactate dehydrogenase (D-LDH) in Leuconostoc citreum KM20. Methods: The D-lactate dehydrogenase gene (LDH) from L.citreum KM20 was cloned and expressed to construct expression plasmid, and then transformed into Escherichia coli BL21 (DE3) for overexpression. Results: The enzymes encoded by LCK_00027 and LCK_00222 were purified by Ni-NTA column affinity chromatography with molecular mass of 40.0 kDa and 38.5 kDa, respectively. The specific activities were 2.18 U/mg and 153.10 U/mg, respectively. The optimal pH and temperature for pyruvate reduction were 8.0 and 40 ℃, respectively, while for the LCK_00222 encoding enzyme lactic acid oxidation the values were 12.0 and 30 ℃, respectively. The two enzymes had high activities toward oxaloacetic acid, sodium phenylpyruvate, and 2-oxoglutaric acid. Ca2+, Cu2+, and Na+ promoted the activity of the two enzymes, whereas Zn2+ and SDS inhibited. In addition, the Kcat/Km of LCK_00027 and LCK_00222 to pyruvate were 6.04×102 L/(mol·s) and 2.28×104 L/(mol·s), respectively. The Kcat/Km of LCK_00222 encoding enzyme to D-lactic acid was 65.0 L/(mol·s). Conclusion: D-LDH-1 and D-LDH-2 are key enzymes catalyzing the synthesis of D-lactic acid in Leuconostoc citrate.
Abstract: Objective： This study aimed to develop an ion chromatography-tandem mass spectrometry (IC-MS/MS) for the analysis of glyphosate and its metabolite amino methyl phosphoric acid (AMPA) residues in tea without derivatization. Methods： Tea samples were ultrasonically extracted with 20 mmol/L NaOH aqueous solution and cleaned up by dispersive solid-phase extraction (150 mg primary-secondary amine (PSA), 15 mg C18, 15 mg graphitized carbon black (GCB)). The samples were separated on an ion chromatographic column AS11-HC-4 μm (2 mm×250 mm) by using an isometric elution procedure of 35 mmol/L aqueous solution of sodium hydroxide as mobile phase. A multiple reactions monitoring (MRM) model was used to obtain the sensitivity of the method, and the isotopically labeled internal standards were applied in the calibration process. Good linearities and recoveries were obtained in the validation process. Results: The correlation coefficients R2 were 0.999 8 and 0.998 2, respectively. The detection limits of glyphosate and AMPA in tea were both 0.05 mg/kg, and the quantification limits were both 0.10 mg/kg. The average recoveries of glyphosate and AMPA were 61.2%～104.9% and 61.5%～83.2%, respectively with RSDs less than 20%. Conclusion: This method meets the requirements of green analytical chemistry and can be used for routine detection of glyphosate and aminomethylphosphoric acid residues in tea.
Abstract: Objective: A formaldehyde detection method was established for the accurate analysis of the migration of formaldehyde in water and acid simulants from the polylactic acid straws. Methods: The preferred chromatographic conditions were: mobile phase water-acetonitrile (Vwater∶Vacetonitrile of 55∶45), column temperature of 35 ℃, detection wavelength of 355 nm. The optimized 2,4-dinitrophenylhydrazine derivative conditions were: the acetic acid in acidic 2,4-dinitrophenylhydrazine solution of 1.5 mL/100 mL (pH 3.07), the molar ratio of 2,4- dinitrophenylhydrazine of quadruple formaldehyde, the reaction temperature of 45 ℃, and the reaction time of 40 min. Results: The linear equation of formaldehyde-2,4-dinitrobenzene was y=55.247 0x-3.849 4 within 1.008 to 70.560 μg/mL, with the correlation coefficient of 0.999 5. The detection limit of the corresponding formaldehyde was 0.066 mg/kg, and the quantification limit of which was 0.22 mg/kg. The formaldehyde-DNPH was stable within 13.5 hours. The average recovery of simulants spiking with formaldehyde in 3 levels was from 92.6% to 104.1%, with SD (n=6) of 0.4% to 3.3%. The maximum migration of formaldehyde from disposable polylactic acid straws to three food simulants (water, 3% acetic acid solution, 4% acetic acid solution) was 1.839 mg/kg, less than the specific migration requirement of 15 mg/kg stipulated by China and the European Union. Conclusion: This method is accurate and efficient enough to apply for the analysis of formaldehyde migration from polylactic acid straws.
Abstract: Objective: To solve the problems of low accuracy and poor efficiency in the existing rice quality testing methods of food enterprises. Methods: Based on a hyperspectral data acquisition system, a fast and non-destructive detection method for stored rice quality was proposed, which combined an improved bacterial foraging algorithm and least squares support vector machine. By applying the improved bacterial foraging algorithm, the hyperparameters (regularization parameter and kernel parameter) of the least squares support vector machine were optimized to achieve rapid and non-destructive detection of rice quality. its performance was analyzed through experiments. Results: The proposed method can achieve rapid and non-destructive detection of fatty acid content in stored rice, with a determination coefficient of 0.940 5, root mean square error of 0.543 5, and an average detection time of 1.12 seconds. Conclusion: The proposed detection method has high detection performance, which can be used for the identification and detection of rice quality.
Abstract: Objective: This study aimed to investigate different discriminant analysis models for pseudo-mixtures of walnut oil and rapeseed oil. Methods: Gas chromatography technology was used to analyze the fatty acid content in the adulterated mixture of walnut oil and rapeseed oil. Chemical stoichiometric methods were used to model the gas chromatography data, and discriminant analysis was performed on different proportions of walnut oil and rapeseed oil mixtures. Results: Pure walnut oil and adulterated walnut oil were distinguihed by using Principal Component Analysis (PCA) identified, and percentage of adulteration in the sample was calculated. 83.33% of the samples were successfully categorized using the Bayes discriminant analysis. Partial Least Squares Discriminant Analysis (PLS-DA) achieved 87.50% discrimination accuracy. Based on the BP neural network model for discriminant analysis, the accuracy of the training set was 84.21% and the accuracy of the test set was 80.00%. For both the training and testing sets, the genetic algorithm-based discriminant analysis using an optimized support vector machine (SVM-ga) achieved 100% accuracy. Conclusion: Multiple analytical models can identify the adulteration ratio of walnut oil and rapeseed oil to varying degrees, among which the SVM-ga model had the best prediction accuracy.
Abstract: Objective: To establish a rapid method for moisture detection of high cellulose and lignin materials. Methods: The areca nut, a Chinese herbal medicine containing high cellulose and lignin, was selected. Use a near-infrared spectrometer to collect near-infrared diffuse reflectance spectra. Apply NIR Cal modeling software to preprocess the spectral data, select the optimal feature wavelengths, and use partial least squares (PLS) analysis to establish a quantitative model for areca nut moisture content. Results: A quantitative model for areca nut moisture content was acquired, with the coefficient of determination of 0.994 2, the root mean square of the calibration error (RMSEC) of 0.50, the coefficient of determination for the validation set of 0.986 7, the root mean square of the prediction error (RMSEP) of 0.68. Conclusion: This method is simple, fast, safe, practical, and accurate, suitable for the rapid determination of moisture content in materials containing high cellulose and lignin.
Abstract: Objective: A high performance liquid chromatography method was developed to determine EDTA and NTA in water. Methods: The samples were derivatized with ferric chloride, used methanol and a 0.2 mmol/L tetrabutylammonium bromide phosphate buffer solution (pH 2.5) as the mobile phase, separated on a Thermo-C18 (4.6 mm×250 mm) column after gradient elution, detected by HPLC with a diode array detector, and used external standard method for quantitation. Results: The content of EDTA and NTA showed a good linear relationship in the range of 0.1～2.0 mg/L, the correlation coefficients were 0.999 5 and 0.999 2 respectively; The limits of detection were 0.05 mg/L and limits of quantification were 0.1 mg/L; The average recoveries were 93.5%～111.4%; And the relative standard deviations (RSD) were 3.63%～7.39%. Conclusion: This method was convenient, repeatable, sensitive, and practical for the detection of EDTA and NTA.
Abstract: Objective: To add a freezing sword inside the evaporator of the ice mould of a direct-cooled block ice machine to achieve rapid ice production. Methods: COMSOL was used to simulate the effects of the cross-sectional shape of the freezing sword and the freezing sword inclination angle on the ice production process. Results: As the ice making process continued, the average internal temperature of the ice mould with additional freezing swords of different cross-sectional shapes decreased and the volume fraction of solid phase in the ice mould increasedd with time, but the average internal temperature of the ice mould with additional freezing swords of circular cross-section was 0.1~0.2 ℃ lower than that of triangular, rectangular and diamond shapes in the same time. In addition, the lower the freezing sword inclination angle was, the faster of the ice production rate it was. Conclusion: The ice-making rate is faster when the cross-section shape of the freezing sword is round or nearly round. Under the premise of ensuring easy de-icing, the angle of inclination of the freezing sword should be reduced as much as possible.
Abstract: Objective： To clarify the interaction mechanism model between screw and grain in grain pile depth, and to determine the mechanical characteristics of screw of spiral robot for granary at different speeds and depths, so as to provide the design basis for the motion control system. Methods： Using mathematical model, combining Janssen grain storage pressure theory and Janosi shear-displacement equation, the shear stress model was established, and then the thrust model of screw was derived from the shear stress model. Through the design and construction of the experimental device, the combination of different speed and pressure was used to carry out the all-factor experiment, and the measured experimental data was compared with the theoretical value. Results： The theoretical value of the thrust model was close to the experimental value, and the curve variation trend was the same. The average relative error of the axial thrust model was 14%, and the average relative error of the resistance torque model was 24%. Conclusion： The screw thrust model based on Janssen grain storage pressure theory and Janosi shear-displacement equation at different depths has high reliability.
Abstract: Objective: To verify whether the structure design of the conveying part and the collecting part of the cleaning device designed for the surplus grain at the bottom of the cottage warehouse is reasonable, and to determine the key parameters of the device operation, so as to avoid the waste of procurement and manufacturing. Methods: Based on discrete element method, EDEM simulation software was used to simulate the operation effect of the transfer part and the collection part, and the drop rate was used as the evaluation parameter. Results: Through the observation and analysis of the simulation results, it was concluded that the optimal running speed of the corrugated flange belt should be controlled between 0.6 m/s and 0.8 m/s under the condition that the transmission and collection parts could meet the design requirements. Conclusion: The simulation study verifies that the structure of the transfer part and the collection part of the surplus grain cleaning device meets the design requirements, and can provide a reference for the design of the equipment for the transfer and collection of grain materials.
Abstract: Objective: A special cutting mechanism for slicing elongated fish with smooth surface was designed. Methods: Taking the slimy eel as the research object, the mechanism of clamping and cutting operation was analyzed. Taking cutting quality and cutting time as test indexes, the influence of main parameters such as clamping wheel speed, cutting tool speed and clamping wheel surface geometry on cutting quality and cutting time were investigated. Results: The main factors affecting cutting quality were blade speed and clamping wheel limit height, and the most important factors affecting cutting time were clamping wheel speed. When the clamping wheel limit height was 5 mm, the blade speed was 1 350 r/min, and the clamping wheel speed wwas 167 r/min, the higher cutting quality score and cutting time could be obtained. Conclusion: The eel can be effectively transported by using the gripper wheel, and efficient and high-speed laparotomy can be achieved by adjusting the speed of the gripper wheel, the speed of the blade and the height of the limit.
Abstract: Objective: To achieve surface wear life prediction of abrasive blast rollers of grinding machines. Methods: The wear images of the grinding roller surface were acquired by the built image acquisition system, and the texture parameters such as second order moments, entropy value, contrast and correlation in the wear cycle of the grinding roller were obtained based on the grey scale co-generation matrix algorithm, and the obtained texture feature parameters were input into the constructed PSO-based LS-SVM algorithm model to finally predict the wear life of the blast roller. Results: The particle swarm algorithm could optimize the penalty factor and kernel parameters of LS-SVM well, and the PSO-LS-SVM algorithm was far superior to the LS-SVM algorithm model. The wear state of the blast roller surface of the mill could be accurately identified using the PSO-LS-SVM algorithm. Conclusion: The system can accurately predict the service life of the blast rollers.
Abstract: Objective: This study aimed to explore the best irradiation method and irradiation dose to treat Choerospondias axillaris pastilles. Methods: C. axillaris pastilleswere irradiated with 0～10 kGy gradient dose of 60Co-γ ray and electron beam respectively, the changes of the indexes including microbial load, protein, fat, total sugar, L(+)-ascorbic acid, organic acids, pH value, sensory quality, and the shelf life quality stored in 0～360 days at room temperature were studied. Results: 60Co-γ ray and electron beam irradiation both had bactericidal effects on C. axillaris pastilles, all microbial limit indexes including aerobic bacterial count, coliform bacteria, mold, and the pathogenic bacteria limit indexes including salmonella and staphylococcus aureus were not detected in the samples with the irradiation dose of 4 kGy. The contents of protein, fat, total sugar, organic acids (mainly citric acid), pH, and sensory quality in C. axillaris pastilleswere not significantly affected by 60Co-γ ray and electron beam irradiation of less than 10 kGy. However, the content of L(+)-ascorbic acid was significantly decreased compared with the control group after irradiation (P＜0.05), it was negatively correlated with irradiation dose, and 60Co-γ ray irradiation had a greater impact than that of electron beam irradiation. The C. axillaris pastillesbatch products were irradiated with 60Co-γ ray and electron beam of 4～10 kGy, the products were stored for 0～360 days at room temperature, and the microbial limit indexes including aerobic bacterial count, coliform bacteria, mold in the products were less than 10 CFU/g. There were no significant changes in the smell, taste, and tissue state of C. axillaris pastilles, but with the extension of storage time, its color deepened due to browning, but it was still acceptable within 270 days of storage. Conclusion: 60Co-γ ray and electron beam irradiation both are effective methods for sterilization and storage of C. axillaris pastilles, and the recommended irradiation dose is 4～10 kGy.
Abstract: Objective: To analyze the effect of apples of different fruit diameters on differential pressure precooling under the same box. Methods: Based on the spherical analogy model and heat transfer theory, the CFD unsteady SST k-ω turbulence model was used to numerically simulate the differential pressure precooling of apples with different air supply air speed, temperature, box opening size and fruit diameter, and three different working conditions were selected for accuracy. The simulation scheme of mixed orthogonal test was used to discuss the effects of different factors and different fruit diameters on the cooling rate and pre-cooling uniformity. Results: The lower of the air supply temperature was, the faster the wind speed was, the smaller of the apple diameter was, and the faster of the cooling rate it was. The higher of the supply air temperature was, the faster the wind speed was, the larger of the opening was, and the better of the uniformity of precooling it was. Based on the comparison of orthogonal test results, the effect of fruit diameter on differential pressure precooling was significant. Conclusion: Apple fruit size has the greatest influence on the cooling rate and uniformity of pre-cooling, and reasonable packaging and stacking methods need to be adopted for apples with different fruit diameters.
Abstract: Objective: Taking Aksu apples as an example, a joint image optimal feature extraction and improved RBF neural network learning apple weight estimation method is designed to overcome the high cost and large error of manual grading and weighing. Methods: Firstly, an apple image acquisition system was established to obtain apple foreground image information. Secondly, the optimal subset extraction strategy for apple image feature sets was designed, by transforming the process of extracting the optimal subset into an objective function optimization problem, and an improved discrete locust optimization algorithm was designed to obtain the optimal apple image feature subset. Finally, a weight estimation model for apples based on RBF neural network learning was constructed, with the optimal feature subset as network input. The locust optimization algorithm was used to optimize the configuration of RBF neural network hyperparameters, to achieve effective estimation of apple weight. Results: The proposed apple weight estimation method had higher accuracy, with an average relative error rate of 1.23% for weight estimation. Conclusion: This method can effectively achieve apple weight estimation and can also be applied to other fruits with similar axisymmetric shapes for weight estimation.
Abstract: Objective: This study aimed to extend the storage period of fresh-cut Lanzhou lily. Methods: Fresh-cut Lanzhou lily was used as raw materials. Following fresh-cut processing, the raw materials were soaked with 0 (CK), 1, 5, and 10 g/L of SI solution to analyze the quality changes of fresh-cut Lanzhou lily during storage. Results: The soaking treatment with 10 g/L of SI could better maintain the brightness of freshly cut Lanzhou lily. At 21 days of storage, the concentrations of malondialdehyde, soluble sugar, and browning were, respectively, 45%, 8%, and 23% lower than those of the CK group. The SI-treated group had significantly decreased polyphenol oxidase, peroxidase, and lipoxygenase (97.22, 0.09, and 11.89 U/g, respectively) activity at the end of storage compared to the CK group (P＜0.05). In addition, electronic nose analysis showed that SI treatment modulated the flavor of fresh-cut Lanzhou lily during storage. Conclusion: SI soaking treatment is a simple, economical, and safe post-harvest treatment technique that can delay the oxidative browning of fresh-cut Lanzhou lily and thus maintain its quality during storage.
Abstract: Objective: To study the effects of different drying processes on the quality of high moisture wheat. Methods: Investigates the changes of wheat quality under different drying processes in three dimensions: appearance quality, nutritional quality and processing quality. Three indicators, namely colour, wet gluten content and drying rate, were selected as response values and combined with response surface analysis to predict the optimal drying process for high moisture wheat. Results: Drying temperature was the main influencing factor. As the temperature increased, the colour of the wheat deepened, the crude protein content decreased, the wet gluten content decreased, the water absorption of the dough increased, the formation time increased, the stabilization time increased, the degree of weakness decreased, the flour quality index under increased, The wheat skin changed from a small raised rectangle to a small sunken pit, and the internal starch granules changed from a smooth round or oval shape to a rough irregular shape. The optimal processing conditions of the response surface were drying temperature 45 ℃, wind speed 0.94 m/s, tempering time 30.4 min. The colour L* 58.811, the wet gluten content of 27.292%, the drying rate of 8.146×10-2%/min and the comprehensive score of 0.613 were obtained with this parameter. Conclusion: The study proved that the optimization of the hot air drying process improved the post-drying quality of wheat to some extent on the basis of ensuring the drying efficiency.
Abstract: Objective: Explored the composition and content of phenolic compounds in tartary buckwheat wine lees, and study their antioxidant activity. Methods: Phenolic compounds in tartary buckwheat wine lees were analyzed by HPLC and LC-MS. And evaluating its antioxidant activity. Results: 7 phenolic compounds were identified from tartary buckwheat wine lees, including 5 flavonoids, with the highest content of rutin of （9.350±0.050） mg/g, followed by quercetin, isoquercetin, kaempferol-3-o-rutoside and kaempferol of two phenolic compounds. At 0.5 mg/mL, the scavenging rates of hydroxyl free radical, ABTS+ and DPPH free radical reached （73.29±0.09）%, （96.21±0.25）% and （82.55±0.68）%, respectively, with FRAP value of （2.49±0.09） mmol/L. Conclusion: The fermented tartary buckwheat lees are rich in phenolic compounds, and the lees extracts has certain antioxidant activity. In addition, at low concentration, the tartary buckwheat wine lees also showes good scavenging effects on hydroxyl radical and ABTS+ radical.
Abstract: Objective： This study aimed to optimize the processing technology of Fenghuang dancong tea. Methods： Headspace solid phase microextraction (HS-SPME), Gas chromatography-mass spectrometry (GC-MS), and spectrophotometer were used to extract, determine and analyze the volatile aroma and non-volatile biochemical components of Fenghuang dancong tea in different stages of processing. Results: The alcohols, aldehydes, ketones and esters showed a decreasing trend while the alkanes and aromatic ring substances exhibited an increasing trend during the processing. The contents of tea polyphenols, amino acids, caffeine, and catechin in non-volatile biochemical components decreased gradually during processing. The contents of soluble sugar and water extract increased gradually. In tea aroma, the contents of indole，α-farnesene, and nerolidol increased significantly during the processing of Fenghuang dancong tea, which are important volatile aroma components of Fenghuang dancong tea. Conclusion： During the processing of Fenghuang dancong tea, the bitter and grassy taste gradually decreased, and the fragrance and fruit aroma gradually increased, which formed the special fruit and mellow taste of Fenghuang dancong tea.
Abstract: Objective: This study aimed to optimize the microwave assisted aqueous two-phase extraction (MATPE) process of polysaccharides from Cornus officinalis and obtain a uniform polysaccharide fraction. Methods: The best extraction technology was determined through an orthogonal experiment. To obtain a uniform polysaccharides fraction (COP-2-S), the crude extract of C. officinalis polysaccharides was purified using DEAE-52 cellulose and Sephadex G-100 column chromatography. The molecular weight of COP-2-S was determined by high performance gel permeation chromatography. The monosaccharide composition of COP-2-S was determined by gas chromatography. The structure of COP-2-S was characterized by UV, and IR spectra, and a scanning electron microscope. Results: The optimal MATPE process of polysaccharides from C. officinalis was as follows: microwave power of 300 W, ethanol volume fraction of 35%, ammonium sulfate mass fraction of 22%, a solid-to-liquid ratio of 1∶20 (g/mL), and the yield of polysaccharides from C. officinalis was (12.04±0.17)%. The molecular weight of COP-2-S was 17 450 Da. The molar ratio of arabinose, glucose, and galactose that made up the monosaccharide was 12.85∶30.71∶18.09. Conclusion: COP-2-S had no characteristic absorption at 260 nm and 280 nm. Besides, COP-2-S had typical infrared absorption characteristics of polysaccharides.
Abstract: Objective: This study aims to investigate the effect of different drying methods on the drying characteristics and volatile flavor of Stropharia rugosoannulata as raw material. Methods： The fresh S.rugosoannulata was dried by freeze-drying, heat pump drying, hot air drying, and microwave drying, and then the physical and chemical indexes were investigated. Results: The contents of crude protein, crude fat, ash, potassium, calcium, total flavonoids, essential amino acids, flavor amino acids and total amino acids are the highest in freeze drying. The six teenamino acids achieved 16.88 g/100 g in the freeze-drying. The rehydration rate and color all play the best performance in freeze drying. The scavenging rate of DPPH radical of S. rugosoannulata polysaccharide reached 61.14% in hot air drying; The rate was hot air drying>heat pump drying>microwave drying>freeze drying. Similarly, the scavenging rate of ABTS radical reached 67.97% in heat pump drying; The rates were heat pump drying>hot air drying>microwave drying>freeze drying. The monosaccharide of S. rugosoannulata is mainly composed of glucose Glc and Galactose gal, among which the content of freeze-dried glucose Glc is the most, accounting for 36.79% of the total sugar; The maximum molecular weight of S.rugosoannulata was freeze-drying; The volatile flavor of S.rugosoannulata different under different drying methods, and the volatile flavor of S. rugosoannulata after drying is quite different from that of fresh S. rugosoannulata. The volatile components in freeze-dried S. rugosoannulata are the most abundant, and some components are high. Conclusion: Freeze-drying has advantages over other drying methods in terms of nutritional composition, rehydration rate, color, and flavor. It has the least impact on the quality of S. rugosoannulata and is the most suitable drying method.
Abstract: Objective: This study aimed to investigate the effect of different drying methods on the edible quality of dried Tibetan pork. Methods: The effects of four drying methods, namely frying, pre-cooking-frying, baking, and pre-cooking-baking, on the edible quality of Tibetan pork jerky were investigated using Tibetan pork as raw material. Results: Different drying methods had significant effects on the quality indexes of dried Tibetan pork such as color rendering, textural characteristics, and nutrient component. Among them, the frying group had the highest sensory score, uniform color, rich meat flavor, moderate hardness, and good eating quality. The baking group had a higher hardness of jerky and poor chewability; And the pre-cooking treatment showed a grayish-brown color of jerky and hardened meat. In addition, pre-cooking led to a significant loss of fatty acids, affecting the original nutritional value attributes of Tibetan pork jerky. Conclusion: Frying can be used as a potential drying method to produce Tibetan pork jerky.
Abstract: Objective: This study aimed to improve the functional characteristics of Polygonati rhizoma （PR）. Methods: Using the freeze-dried fresh PR and nine-steam-nine-bask processing PR as control products, the study comprehensively compared and analyzed human sensory, electronic sensory, color, fluidity, dissolving ability, extract content, total polysaccharide content and total saponin content in PR powder modified by extrusion cooking. Results: Extrusion cooking effectively eliminated the bad taste and improved the color and fluidity of PR powder. Compared with the nine-steam-nine-bask processing, extrusion cooking significantly increased the total polysaccharide content and total saponin content, with increase rates of 49.27% and 69.10%, respectively. Conclusion: Extrusion cooking can effectively improve the functional characteristics of PR, and enhance the controllability and stability of processing quality.
Abstract: Objective: This study aimed to optimize the pectin extraction yield from immature fruits of Guanxi pomelo by L. plantarum fermentation and analysis of the properties of pectin extracted by L.s plantarum fermentation. Methods: Taking the extraction yield of pectin as the index, orthogonal test was used to optimize the process conditions of fermentation of immature fruits of Guanxi pomelo by L. plantarum, and the content of galacturonic acid, degree of esterification, protein, water-holding capacity, oil-holding capacity, emulsifying activity and emulsion stability of pectin were determined. Results: The optimal conditions for fermentation of immature fruits of Guanxi pomelo by L. plantarum were as follows: fermentation temperature of 37 ℃, L. plantarum fermentation inoculum of 14%, liquid-solid ratio of 25∶1 (mL/g), and fermentation time of 12 h. Under the control of these conditions, the extraction yield of pectin was 11.60%, and the content of galacturonic acid; the degree of esterification, protein, water-holding capacity, oil-holding capacity, emulsifying activity and emulsion stabilities were about 26.13%, 68.58%, 0.53 g/g, 7.01 g/g, 14.33% and 33%, respectively. Conclusion: The extraction yield of pectin extracted by fermentation of L. plantarum was similar to that of the acid process, and the obtained pectin was highly esterified pectin with good application properties.
Abstract: Objective: This research aimed to study the preparation of standardized and stable sourdough starter, to explore the effects of different drying processes and protective agents on the survival rate of sourdough, and examine its storage activity. Methods: A variety of fruits were selected to prepare sourdough, the fermentation process was studied, and the strains were isolated and identified by ITs and 16s gene sequencing in the database. The optimum scheme was obtained by selecting the drying process, sample state and protectant formulation with the activity after drying and storage activity as indexes. Results: It was found that the bread prepared with grape sourdough had the best specific volume, porosity and hardness. On this basis, the drying survival rate and storage activity were used as indexes to study the combination of drying protectants. Finally, two better protective agent formulations were obtained by orthogonal experiment: ① Freeze-dried the dominant pure bacterial solution, skim milk 35%, maltodextrin 7.5% and trehalose 25%, and the drying survival rate was about 93%. ② Spray dried sourdough germ whole, skim milk 35%, maltodextrin 10% and trehalose 15%, and the drying survival rate was about 90%. Conclusion: It was found that the storage activity of the spray-dried starter decreased rapidly, while that of the freeze-dried starter was slower.
Abstract: Objective: This study aimed to optimize the process parameters of fermentative Cynanchum auriculatum (CA) tablets to develop a new type of fermented product of CA. Methods: Taking complete slices of CA as raw materials, the process parameters of fermentative CA tablets were optimized by response surface methodology based on single factor experiments with sensory score and total acid content as indicators, and the antioxidant activity and amino acid content of fermentative CA tablets were tested. Results: The optimal process parameters for fermentative CA tablets were material liquid at ratio 1∶1, fermentation at 31 ℃, inoculation amount 9.6% and fermenting for 25 h. The sensory score was 89.33, and the total acid content was 0.726 g/100 g under the control of theoptimal processing conditions. At the concentration of 10 mg/mL, the total antioxidant capacity of the fermentative CA tablets alcohol extract was 2.05 U/mL, and the scavenging rate of DPPH and ABTS+ free radicals was 32.18% and 45.89% respectively. Test results of the amino acid content showed that the content of aromatic amino acids in CA tablets increased by 47.22% after fermentation. Conclusion: Fermentative CA tablets obtained under the control of the optimal processing conditions have complete morphology and structure, uniform color, harmonious sourness and sweetness, pleasant wine aroma and characteristic flavor of CA and high antioxidant activity, indicating the product has achieved the expected effect.
Abstract: Polysaccharides are the main active ingredients of edible fungi, which have been widely utilized in the food industry. As a member of the truffle family, Tuber are rich in polysaccharides. Previous studies mainly focused on solvent, ultrasound-assisted, microwave-assisted, enzyme-assisted and pressurized liquid extractions regarding the extraction methods of Tuber polysaccharides. The molecular weight, monosaccharide composition and content, configuration, and ligation mechanism of sugar residues, along with the polysaccharide types of Tuber polysaccharides, have all been studied in relation to the characterization of chemical structures. Additionally, the antioxidant, antitumor, hypoglycemia, anti-fatigue, and immunomodulatory activities have been evaluated as well. In food processing, polysaccharides have been currently applied in the production of pastries and lozenges. Therefore, the purpose of this research is to discuss the most current developments in extraction techniques, including chemical structures, functional properties, and applications of Tuber polysaccharides. This provides a theoretical foundation for future growth in their food applications.
Abstract: Flour loses a large amount of dietary fiber (DF) during precision processing, which is considered an important component of a healthy diet and has various physiological activities. This review introduces the common modification methods of DF and summarizes the change rules and reasons of physical and chemical properties and physiological activities of DF after modification. Additionally, the applications of DF in dough, biscuits, noodles, bread, steamed bread and cakes are discussed. The current issues and potential future development paths are also highlighted.
Abstract: Mung beans are rich in nutrients, but their dense structure and dense cortex lead to long a maturation time and poor edible convenience. To provide an empirical basis and novel ideas for future research on the pre-ripening of mung beans, this review analyzes pre-ripening, specifically focusing on the pre-ripening process of mung beans and the effects of different processing methods on the edible quality and nutritional components of mung beans. Moreover, the development direction of preripening technology of mung beans is also prospected.
Abstract: Amide alcohol drugs have a long half-life and are difficult to excrete through the metabolic process after entering the human body. Excessive amide alcohol drugs will cause serious harm to human organs. Therefore, China has formulated a strict maximum residue limit standard for amide alcohol drugs, in which chloramphenicol can’t be detected in all edible tissues. This review introduces the application of chromatography, mass spectrometry, electrochemical method, electrochemiluminescence method, immunoassay, fluorescence method and surface-enhanced Raman spectroscopy method in the detection of amide alcohol drugs in animal-origin foods, and the advantages and disadvantages of these methods are analyzed and new techniques for the detection of amidol alcohol drugs in the future are prospected.
Abstract: This review introduced the classification, structure and physical and chemical properties of dietary fiber, and summarized the relevant research literature on the modification methods and physicochemical properties of dietary fiber at home and abroad in recent years. The development direction of the physicochemical properties of dietary fiber and its modification methods were also prospected, in order to provide a theoretical reference for its efficient and comprehensive utilization.
Abstract: Objective:Improve the quality of dried okra products.Methods:The rehydration ratio, shrinkage rate, vitamin C content, drying time and sensory score were used to analyze the effects of different pretreatment methods on the quality of dried okra products, and the coefficient of variation method was used for comprehensive weighted evaluation.Results:The results showed that blanching and ultrasonic pretreatment can significantly increase the rehydration ratio of the dried sample (P＜0.05). The shrinkage rate was most affected by blanching. The vitamin C content of the pretreatment group was lower than that of the control group, and the ultrasound treatment group had the least loss. The blanching and ultrasonic pretreatment can shorten the drying time, and sensory scores of samples pretreated by ultrasound and color protection were significantly higher than those pretreated by blanching (P＜0.05). The comprehensive evaluation by the coefficient of variation method showed that the quality of the okra pretreated by ultrasonic was the best, followed by the color protection treatment, and the blanching treatment had the lowest comprehensive score. When the ultrasonic pretreatment temperature was 20 ℃, the comprehensive score of the dried sample obtained was the highest, which was 0.907.Conclusion:The research showed that the ultrasonic pretreatment was a better pretreatment method with hot air drying of okra.
Abstract: Objective:This study aimed to provide strategy for controlling the fungal diseases of postharvest blueberry in Sichuan province.Methods:The pathogenic bacteria from 14 planting bases in Sichuan Province were isolate, identified, pathogenicity determination. Moreover, the effects of temperature and light on mycelia growth of the dominant and subdominant strains of blueberry after harvest were studied, and the effective natural antibacterial components against them were screened.Results:The blueberry postharvest rot diseases were caused by the following nine kinds of fungi:Aspergillus niger,Aspergillus tubingensis,Neofusicoccum parvum,Neopestalotiopsissp.,Fusarium graminearum,Alternaria alternata,Mucor fragilis,Penicilliumsp.,Cladosporium xylophilum.Aspergillus niger was the dominant species with the highest isolation frequency and the most pathogenic, andNeopestalotiopsissp.,Alternaria alternata,Penicilliumsp.,Cladosporium xylophilum were the subdominant species with isolation frequencies greater than 10%. The optimum growth temperature ranged from 20 ℃to 35 ℃of dominant and subdominant strains of blueberry postharvest. The effects of light on the mycelia growth ofA. niger，Neopestalotiopsissp., A. alternata,and C. xylophilum were significant，but that was insignificant on the growth ofPenicilliumsp.strains. Thymol showed good broad-spectrum antibacterial activity, the EC50 values of dominant and subdominant strains of blueberry postharvest was 30~50 mg/L, while the thymol applied directly to blueberry postharvest fungal control in aqueous solution should not be higher than 50 mg/L.Conclusion:Thymol is more effective on postharvest diseases of blueberry in Sichuan province.
Abstract: Objective:In order to preserve more volatile components of celery and reduce its moisture content. Methods:A hot-air coupled microwave drying system based on aroma detection was designed. An electronic nose (PEN3) was applied to detect volatile components, assisted with GC-MS to measure the specific content of volatile components. Based on constant temperature drying (50, 60, 70 and 80 ℃), sensor 7 and 9 were chosen for subsequent combined control. Results:Comparing with constant temperature drying, the combined control drying using volatile compounds detection could retain more volatile substances, and a good balance had been achieved between the quality of the dried product and the drying rate. The drying time of combined control was 67 min, closing to constant temperature drying at 70 ℃ (63 min). Meanwhile, optima color difference (16.313±1.745) and sensory evaluation (28.9) were obtained under combined control drying. Conclusion:Microwave coupled hot-air drying control of celery stalks based on volatile compounds detection could be applied to produce high-flavor celery stalks.
Abstract: An analytical method for the simultaneous determination of 19 kinds of organochlorine pesticides in apple-pear was established based on optimized solid-phase extraction coupled with gas chromatography-mass spectrometry（SPE-GC/MS）. Different extraction conditions, included extraction solvent, extraction solvent volume, sample weight, solid phase extraction clean-up and eluent were optimized during the sample pretreatment. The quantification were analyzed by GC/MS in selected ion monitoring （SIM） mode and the external standard method. The method showed good linearity (R2≥0.996 7) for all the pesticides. The recoveries at three spiked levels (20, 40, and 200 μg/kg) ranged from 86.1% to 108.9% with the relative standard deviation below 10%. The limit of detection ranged from 3 to 6 μg/kg and the limit of quantification ranged from 10.0 to 20.0 μg/kg the for 19 kinds of pesticides, respectively. The method was simple, accurate and showed high sensitivity for screening and detection of the 19 kinds of pesticides in apple-pear.
Abstract: Based on the scientific theory of modern nutrition and functional food science, this paper uses biotechnology and information digital technology to establish a more precise, flexible, integrated and digital functional food research and development system-flexible precise nutrition intervention system (FPNIS) which improves the shortcomings of the two common functional food research and development models that are based on traditional Chinese herbal medicines or simple ingredient dietary supplements. Through the establishment of FPNIS, provide a new way to explore the research and development of efficient and precise functional food, and analyze its trend.
Abstract: Objective: To improve the development and utilization rate of Lycium barbarum in the saline-alkali land of the Yellow River Delta. Methods: Ultraviolet spectrophotometer was used to determine the scavenging effect of Lycium barbarum oligosaccharide on free radicals and its effect on the growth curve and pH value of Bifidobacterium adolescentis, so as to determine its antioxidant performance and the ability to proliferate probiotics. Results: The concentration of Lycium barbarum oligosaccharide reached 2.0 mg/mL, the maximum scavenging rates of DPPH·, ABTS+ and hydroxyl radical reached (65.32±0.03)%, (99.93±0.05)% and (21.86±0.01)%, respectively, when the concentration was between 0.1~0.5 mg/mL, it showed good total reducing power. The OD value of Bifidobacterium adolescentis increased with the increase of Lycium barbarum oligosaccharide concentration, and the pH value was negatively correlated with the cell concentration. Conclusion:Lycium barbarum oligosaccharides show strong antioxidant activity and the ability to proliferate probiotics.
Abstract: Objective:The flavor formation process of stewed pork was investigated in this study. Methods: Electronic nose and gas-phase mass spectrometry (GC-MS) techniques were used to compare the key processes such as bleaching, frying, stewing and addition of sauces during the processing of stewed pork, and to analyze the changes of flavor compounds. Results: The results of electronic nose measurement were consistent with the results of gas chromatography analysis. The flavor content of raw pork and sauces was the highest, and the flavor substances decreased in the blanching, frying and stewing stages. However, the characte-ristic flavor substances were formed continuously. A total of 148 compounds were detected by GC-MS, including 39, 32, 23, 20, 38, and 65 compounds in raw pork, blanched, fryed, stewed and finished products and sauces, respectively, which mainly produced aldehydes and ketones, esters and alcohols, heterocyclic compounds, and aromatic hydrocarbons and their derivatives. The characteristic flavors of finished products were hexanal, benzaldehyde, 1-octen-3-ol, cinnamaldehyde, 2-pentylfuran, 2-acetyl pyrrole, 2,3-dimethyl-5-ethylpyrazine, etc. The content of acetoin was higher in the pre-preparation stage of stewed pork, while methoxy-phenyl-Oxime stayed high in all of the processes. Conclusion: The electronic nose technique can be used to detect the changes of flavor substances in different processing stages of stewed pork, but the specific substance changes need to be determined and analyzed by GC-MS.
Abstract: Objective: This study focused on improving the production of chitosan oligosaccharides by chitinase degradation of chitin. Methods: Using genetic engineering methods to clone, prokaryotic expressing, and investigating enzymatic properties of the chitinase from Streptomyces diastaticus, and the chitinase activity was explored by homology modeling, amino acid comparison of the catalytic domain, and site-directed mutagenesis. Results: After cloning and prokaryotic expression, the enzyme production cycle was shortened from 7 d to 24 h, and the enzyme activity reached 132 U/L, which was 32% higher than the original bacterial enzyme activity (100 U/L). The amino acids that determine the activity of chitinase was Asp at position 128, 130, and Glu at position 132 of the catalytic domain. Conclusion: Clonal expression of the chitinase gene resulted in a shorter enzyme production cycle and increased enzyme activity.
Abstract: Objective:To monitor and control mold spores contamination effectively in food (beverage) processing workshops.Methods:The mold spores are enriched and classified by microfluidic chip, and the air aerosol was collected in 2~10 micron channel and prepared on film. Finally, spore images were taken by camera and electron microscope, and spores were detected, distinguished and counted by Canny algorithm.Results:Compared with the traditional falling plate method, the detection device designed in this paper could detect 103cell/mL mold spores sprayed in the air within 20 minutes.Conclusion:Using airborne UAV to detect mold pollution in food (beverage) processing workshop in the air is simple and feasible.
Abstract: Objective:This paper proposed a genetic fuzzy PID cascade control system. Methods:Taking the outlet temperature as the main control quantity and the inlet temperature as the secondary controlled quantity, a cascade control system was made. The genetic fuzzy PID controller was used to control the main loop, and the PI controller was used to control the secondary loop. Results:Compared with conventional PID control, the cascade genetic fuzzy PID control had the advantages of shorter regulation time, better robustness. Conclusion:The genetic fuzzy PID cascade control system for soy flour spray drying tower can improve the quality of soy flour production.
Abstract: Objective:This study aimed to explore the effect of Pediococcus pentosaceus J8 fermented kiwifruit on bread baking and flavor profile characteristics of wheat bread. Methods: The changes in β glucosidase enzyme activity, organic acids and flavor compounds during kiwifruit fermentation were analyzed. The physical and chemical properties of wheat dough incorporated with fermented kiwifruit were determined. Moreover, the changes in total dietary fiber and total amino acid content, bread quality and flavor characteristics of the resulted bread were also determined. Results: After 15.5 hours of fermentation, the β glucosidase activity reached 55.13 U/L, and the content of lactic acid and acetic acid significantly increased. A total of 110 flavor compounds were detected by GC TOF/MS in kiwifruit. After fermentation, the content of acids, esters, alcohols and terpenes increased, while the content of aldehydes and ketones decreased. For the first time, α angelica lactone, furfuryl acetate and pantolactone were found in kiwifruit. In dough, compared with the unfermented group, the α amylase and protease activities increased by 14.86% and 18.63%, respectively after incorporation of fermented kiwifruit. In bread, compared with the unfermented group, the hardness (11.58%) decreased, while the soluble dietary fiber, total amino acids and specific volume increased by 12.54%, 41.02% and 18.59%, respectively. In addition, bread incorporated with fermented kiwifruit tasted better, had an increased content (27.78%) and type (45.10%) of flavor compounds and a higher overall acceptability than bread incorporated with unfermented kiwifruit. Conclusion: Fermenting kiwifruit with Pediococcus pentosaceuscan improve the flavor and baking characteristics of bread.
Abstract: Objective: This study aimed to provide theoretical support for the processing application of surimi products by comparing the gel characteristics of Chinese herring surimi and the common surimi. Methods: The surimi gels of Chinese herring, silver carp, white croaker and golden-thread fish were prepared, and the difference of gel strength, texture profile analysis (TPA), gelation index, gel deterioration index, water retention, whiteness and microstructure among the four kinds of surimi were investigated. Results: The hardness, chewiness, adhesiveness, gel strength and water retention of Chinese herring surimi were significantly higher than the those of silver carp surimi (P＜0.05). The above results were consistent with the microstructure properties of Chinese herring surimi gel which appeared a smooth, dense and porely unifrom surface. Moreover, the whiteness of Chinese herring surimi (71.23±0.09) was significantly higher than that of white croaker surimi (67.81±0.25) and white croaker surimi (67.16±0.55). Conclusion: The Chinese herring surimi has the advantages of both freshwater and seawater surimi in gel strength, whiteness, water retention and microstructure formation.
Abstract: Objective:This experiment is to judge the comprehensive quality of Hunan bacon.Methods:The contents of 8 biogenic amines in Hunan bacon were determined by HPLC-UV. The contents of moisture content, peroxide value and nitrite were measured.Results:The facts showed the total amount of biogenic amines was 127.22~166.24 mg/kg, which were mainly composed of cadaverine, putrescine, spermine and tyramine. The content of histamine was 0.43~10.24 mg/kg while the content of tyramine was 2.11~57.60 mg/kg. As for the physical and chemical indicators, the moisture content in the sample ranged from 13%~23%, the detection range of peroxide value was 0.014 2~0.035 0 g/100 g, with the nitrite content ranging from 2.15 to 7.50 mg/kg.Conclusion:The content of biogenic amines in Hunan bacon products is lower than the European Union and US FDA standard. All physical and chemical indexes meet the national standard.
Abstract: Objective:This study focuses on improving the comprehensive utilization rate of Polygonatum cyrtonema.Methods:The contents of total flavonoids, total saponins and total phenols from roots, stems, leaves, flowers and buds, of P. cyrtonema were determined. The scavenging rates of DPPH·, ·OH and nitrites in extracts of above tissue were measured and compared as well. Results:The contents of total flavonoids and total phenols five different kinds of non-medicinal tissue were in the same order, in which from highest to lowest was, leaves, buds, flowers, stems and roots, and the content of total saponins in flower was the highest In terms of antioxidant activity, the DPPH ·, ·OH and nitrite scavenging rate of leaf extract were the highest, followed by buds and flowers. Correlation analysis showed that the clearance of DPPH ·, · OH and nitrite by the extract from different tissue showed a certain positive correlation with the contents of total flavonoids, total saponins and total phenols. Conclusion:The extract of non-medicinal parts of P. cyrtonema has good biological activity.
Abstract: Objective:This study aims to explore the correlation between the types and contents of fatty acids and lecithin in fresh walnut.Methods:A kinds of 20 walnuts were selected from Chengdu in Sichuan Province. The method of the gas chromatography and the high performance liquid chromatography were used for quantitative determination. Correlation analysis and cluster analysis were used to analyze the results.Results:The fatty acid composition of 20 kinds of fresh walnut was the same basically, with significant differences in content (P＜0.05). Longnan 15 had the highest oleic acid content. The contents of linoleic acid, arachidonic acid and cis-11-eicosenoic acid of Guangfeng 1 were the highest. The variation coefficient of lecithin was relatively small, and the content of lecithin was the highest in Xilo 3. The content of lecithin in fresh walnut had a high correlation with the content of fatty acids, and unsaturated fatty acids are highly associated. When the euclide distance was 15, the 20 walnut species could be divided into 3 categories.Conclusion:Longnan 15 and Guangfeng 1 are walnut varieties with high oil quality relatively; Xilo 3 is a walnut variety resource with high content of lecithin relatively.
Abstract: Objective:This study aimed to explore the distribution and speciation of selenium amino acids in different solubilized proteins of selenium-enriched broccoli, soybean, corn and barley seedlings.Methods:The contents of selenomethionine, selenocysteine, methylselenocysteine and selenethionine in four selenium-enriched cereals and cruciferous agricultural products were determined by high performance liquid chromatography-hydride generation-atomic fluorescence spectrometry. Moreover, the distribution characteristics of each selenium amino acid in albumin, globulin, gliadin and glutelin with different solubilized proteins were analyzed.Results:The content and distribution of selenium amino acids of the four selenium-enriched plants in different protein components were significantly different (P＜0.05). SeMet was the main organic selenium form in selenium-enriched soybean, corn and barley seedlings, and its distribution of the four types of protein fractions was more consistent and the relative contents were all higher than 66%.However, no SeEt was detected. The organic selenium forms in selenium-enriched broccoli were mainly SeCys2 and SeMet, following by MeSeCys. SeCys2 and SeMet were more uniformly distributed in the albumin and glutenin which accounted for about 36% of the organic selenium content, but SeMet was present in the globulin and gliadin with the highest relative content of 60%. SeCys2 accounted for about 34% of the organic selenium content, while SeEt was the smallest constituent accounted for about 5%.Conclusion: SeMet is the main selenium specie in different soluble proteins of Graminaceous and cereals (selenium-enriched soybean, corn and barley seedlings); SeMet and SeCys2 are the main selenium species in different soluble proteins of selenium-enriched broccoli, and there are also MeSeCys in albumin and glutelin.
Abstract: Objective:Two kinds of titration methods (automatic potentiometric titration and indicator titration) of GB 5009.229 and GB 5009.227 were used to analyze the expanded uncertaintyof the determination of acid value and peroxide value in edible oil.Methods:CNAS-GL006 was used for the uncertainty component and extended uncertainty of the measurement results of the two titration methods.Results:The results showed that the standard solution was the main factor affecting the uncertainty of acid value (value) and peroxide value.Conclusion:The effects of the two titration methods on peroxide value and acid value (value) of edible oil is relatively small, and the appropriate titration method can be selected according to the actual situation for the basic testing organization.
Abstract: Objective:This study focuses on the effects of twin-screw extrusion on the functional properties and structure of pea protein. Methods: The color change of pea protein extrudates were analyzed by automatic colorimeter, the water holding capacity and emulsifying characteristics of pea protein were analyzed by chemical analysis. The microstructure of pea protein and its extrudates were observed by scanning electron microscope, and the secondary structure of the extrudates were analyzed by Fourier transform infrared spectroscopy. Results: After extrusion treatment, no significant difference was found in the color of pea protein, indicating that the pea protein had a better product color and the water holding capacity was significantly reduced (P＜0.05), with the emulsibility and emulsification stability significantly increased (P＜0.05). Scanning electron microscope showed that the microstructure changed obviously, resulting in protein aggregates with compact structure. The infrared spectrum showed that no new characteristic peaks appeared after extrusion treatment, but the secondary structure conversion occurred; β-sheet and α-helix structure transformed into β-turn and random coil structure, and the structural stability increased. Conclusion: After extrusion treatment, the pea protein retained its original product color, emulsification characteristics were significantly improved, the structure was dense and stability was enhanced.
Abstract: Objective:A method based on the high resolution mass spectrometry library and diagnostic ratio of characteristic components was established to identify the illegally added psoraleae fructus in wine and tea.Methods:High resolution mass spectrometry library of psoraleae fructus was constructed by high performance liquid chromatography quadrupole time of flight mass spectrometry (HPLC-TOF-MS) for preliminary screening. Combined with the diagnostic ratio method of the characteristic components by, high performance liquid chromatography, psoraleae fructus in different 20 samples of mixed wine and mixed tea from different picking time and origin was tested and analyzed The diagnostic ratio of characteristic component peak area, which was less affected by the origin, picking time and processing technology, has no significant difference between different matrix groups, and was selected as the identification index.Results:High resolution mass spectrometry library of psoraleae fructus was established by high performance liquid chromatography quadrupole time of flight mass spectrometry (HPLC-TOF-MS) for preliminary screening. Corylia/psoralen and psoralen/isopsoralen were selected as the two characteristic groups. The box diagram was drawn to determine that the non-abnormal value range of Corylia/Psoralen was 0.061~0.115, and the non-abnormal value range of Psoralen/Isopsoralen was 1.14~1.68. The established screening and confirmatory methods were validated by commercial samples.Conclusion:The method is simple and efficient, which provides technical support for cracking down on illegal addition of psoraleae fructus in wine and tea.
Abstract: Objective: A microbial enhancer with high-yield glucoamylase was developed from medium-high temperature Daqu and applied to the brewing of Daqu Baijiu for the yield increasing. Methods: Strains with high yield of glucoamylase was isolated from medium-high temperature Daqu and used to make Miqu. Miqu was employed as an enhanced starter in the brewing of Daqu Baijiu, and the yield of Baijiu were tested. Results: A strain M-1 with higher glucoamylase production was isolated and identified as Rhizopus oryzae. The results of the optimized conditions for Miqu making was as follows: bran and rice (2∶8), moisture content 45%, incubation time 72 h, drying temperature 40 ℃. Under the control of these conditions, the glucoamylase activity of Miqu is as high as 864.50 U/g. When appling the Miqu to the brewing of Daqu Baijiu, the results showed that when the addition amount of by, and the yield increased to 43.17% with the addition of 2% (weight of grain) M-1 Miqu. Conclusion: This study established a method for preparing Miqu from Rhizopus oryzae to improve the glucoamylase activity of medium-high temperature Daqu.
Abstract: Objective:In order to established a non-destructive, rapid and efficient method for detecting the moisture content of rice. Methods:This study, 161 rice samples were collected from 5 different regions were studied by near infrared spectroscopy combined with stoichiometry. By eliminating abnormal spectra and preprocessing the spectra, the prediction model of rice moisture content was established by partial least squares regression. Results:15 abnormal spectrum samples were eliminated using the method of principal component analysis combined with mahalanobis distance. The best spectral pretreatment was to eliminate the constant offset. The prediction model R2CAL established in the training set was 0.994 3, root mean square error of calibration (RMSEC) was 0.21%, R2CV was 0.993 6, and root mean square error of cross validation (RMSECV) was 0.32%, which indicated that the cross-validation of the prediction model had high accuracy in predicting sample moisture content. The prediction model was tested with the validation set samples. The validation determination coefficient R2VAL of the model validation set was 0.980 1, the root mean square error of prediction (RMSEP) was 0.36%, and the relative percent deviation (RPD) was 7.14, which indicated that the prediction model had high prediction accuracy for the unknown samples. The P-value (two-sided) of the mean equation T-test of the measured and predicted values of the samples in the validation set was 0.879, and the difference between the measured and predicted values of the samples in the validation set was not significant, indicating that the prediction results of the prediction model were highly reliable. The error between the predicted value and the measured value of the verification set samples was within ±1%, and more than 90% were within ±0.5%. Conclusion:The established rice moisture prediction model can be applied to actual production, and it provides a non-destructive, rapid and high-accuracy detection method for the inspection of rice harvesting and storage.
Abstract: Objective: A surface-enhanced Raman spectroscopy (SERS) method was developed for non-targeted screening of PDE-5 inhibitors in health wine. Methods: An appropriate SERS base of colloidal gold was prepared, and SERS analysis was conducted after the base was mixed with 78 kinds of PDE-5 inhibitors. The spectrogram screening database was established, and whether the matching degree was higher than 70% was used as the basis for judging whether the PDE-5 inhibitors were suspected to be added. Finally, the sensitivity and specificity of the method were investigated. Results: The best method of preparing PDE-5 inhibitors of SERS base was adding 1.0 mL 1% chlorauric acid and 0.7 mL 1% trisodium citrate into 98.3 mL ultrapure water. The lowest concentrations were sildenafil 0.05 mg/L, tadanafil 0.5 mg/L, thiosildenafil 0.05 mg/L and acevardenafil 0.1 mg/L, respectively. The qualitative results of simulated samples were consistent with those of HPLC-MS. Conclusion: In theory, this method can be used to screen non-targeted illegal addition of PDE-5 inhibitors in health wine.
Abstract: Objective:Two kinds of titration methods (automatic potentiometric titration and indicator titration) of GB 5009.229 and GB 5009.227 were used to analyze the expanded uncertaintyof the determination of acid value and peroxide value in edible oil.Methods:CNAS-GL006 was used for the uncertainty component and extended uncertainty of the measurement results of the two titration methods.Results:The results showed that the standard solution was the main factor affecting the uncertainty of acid value (value) and peroxide value.Conclusion:The effects of the two titration methods on peroxide value and acid value (value) of edible oil is relatively small, and the appropriate titration method can be selected according to the actual situation for the basic testing organization.
Abstract: Objective:This study aimed to explore the effect of Pediococcus pentosaceus J8 fermented kiwifruit on bread baking and flavor profile characteristics of wheat bread. Methods: The changes in β glucosidase enzyme activity, organic acids and flavor compounds during kiwifruit fermentation were analyzed. The physical and chemical properties of wheat dough incorporated with fermented kiwifruit were determined. Moreover, the changes in total dietary fiber and total amino acid content, bread quality and flavor characteristics of the resulted bread were also determined. Results: After 15.5 hours of fermentation, the β glucosidase activity reached 55.13 U/L, and the content of lactic acid and acetic acid significantly increased. A total of 110 flavor compounds were detected by GC TOF/MS in kiwifruit. After fermentation, the content of acids, esters, alcohols and terpenes increased, while the content of aldehydes and ketones decreased. For the first time, α angelica lactone, furfuryl acetate and pantolactone were found in kiwifruit. In dough, compared with the unfermented group, the α amylase and protease activities increased by 14.86% and 18.63%, respectively after incorporation of fermented kiwifruit. In bread, compared with the unfermented group, the hardness (11.58%) decreased, while the soluble dietary fiber, total amino acids and specific volume increased by 12.54%, 41.02% and 18.59%, respectively. In addition, bread incorporated with fermented kiwifruit tasted better, had an increased content (27.78%) and type (45.10%) of flavor compounds and a higher overall acceptability than bread incorporated with unfermented kiwifruit. Conclusion: Fermenting kiwifruit with Pediococcus pentosaceuscan improve the flavor and baking characteristics of bread.
Abstract: Objective:This study aimed to establish a new method for the determination of matrine and oxymatrine in honey by UPLC-MS/MS. Methods: The honey was dissolved in water, and the liquid-liquid extraction pretreatment technology was adopted. The extraction was achieved using ammonia-acetonitrile, with the addition of sodium sulfate to induce a salting out effect. Chromatographic separation was achieved on Inspire HILIC column in the mobile phase composition of acetonitrile and 0.1% formic acid5 mmol/L ammonium acetate buffer. Mass Spectrometry was carried out under the multiple reaction monitoring (MRM) mode with positive electrospray ionization (ESI+) and external standard method for quantitative analysis. Results: The linear relationship between matrine and oxymatrine was observed in the range of 1~100 ng/mL, with correlation coefficients higher than 0.998. The detection limit and quantitative limit of matrine and oxymatrine in honeywere 0.1 μg/kg and 0.3 μg/kg, respectively. The average recoveries of matrine and oxymatrine were 90.9%~95.1% and 80.9%~84.3%, respectively, at the spiked levels of 1, 10 and 100 μg/kg, with the relative standard deviations (RSDS)＜ 10% (n=6). The validated method was then successfully applied to the determination of matrine and oxymatrine in 45 commercially available honey, and the results showed that the detection probability and content of matrine and oxymatrine in acacia honey were relatively high. Conclusion: The established method is accurate, rapid, and sensitive, Moreover, a simultaneous preparation of multiple sample extracts is available, and it can used for the routine determination of matrine and oxymatrine in honey.
Abstract: Objective：This study focused on the antioxidant andimmune enhancing effects of L.bar barumpu ree.Methods：Theantioxidant capacity of L.bar barum puree was measured byes-tab lishing an acute liver injury model.The immune activity of L.bar barum protoplasmwas evaluated by measuring the index ofimmune organs， the content of serum hemolysin and the degreeof plantar thickening.Results：Both low and medium doses of L.bar barum puree could significantly increase the content of glut a-thione peroxidase(GSH PX) in serum(P＜0.05， P＜0.01) andglutathione(GSH) in liver tissue(P＜0.05) ， and significantlydecrease the content ofprotein carbonyl in liver tissue ofmicewith acute alcoholic liver injury(P＜0.05， P＜0.01)andthecontent of malondialdehyde(MDA) (P＜0.05， P＜0.01) ， andthis indicate L.bar barum protoplasm hadantioxid antact ivity.After continuous gavage of L.barbarum protoplasm for 45 days，the organ development of normalm icewasn otaffected.Compared to the untreated mice， the content of serum hemolysin(P＜0.01)and the degree of foot thickening(P＜0.05)andphagocytosis index(P＜0.01) increased significantly， indicatingthat L.bar barum puree could enhance mice immunity.Conclusion：Eating a certain dose of L.bar barum puree can en-hance the antioxidant capacity and immune ability.
Abstract: Objective：This study aimed to clarify the content anddistribution of polyphenols in fruit juice samples and explore theintrinsic connection of the content of polyphenols with the taste offruit juice .Methods： 15 kinds of polyphenols in fruit juice sampleswere determined by HPLC-MS/MS following ethanol ultrasonic-assisted extraction.Various statistical methods such as correlation and_cluster analysis，were used to establish thesensory evaluation system of fruit juice with the values ofdifferent tastes，including sweetness，sourness，bitterness，salty， umami， astringency and piquancy.Lastly， the relationshipbetween the content of polyphenols and sensory evaluation wasexplored by correlation analysis .Results： 14 types of fruit juiceswere divided into four categories owing to their taste， namelysweet， sour-sweet， bitter and bitter-astringent.There was sign if-icant positive relationship between the content of total polyp he-nols， phenolic acids， flavonoids， chl orogenic acids， free phenolicacids and value of astringency.Conclusion：Thecontentsofpoly-phenol varied greatly in different fruit juices， and those withbitter and astringent taste often had high content of polyphenol.However， those with sweet taste had low content of poly oh enol.Polyphenolic compounds， especially the free phenolic acids werethe key substances affecting taste of astringency of fruit juice.
Abstract: Objective: The adsorption performance and mechanism of Xanthoceras sorbifolia shell biochar activated by phosphoric acid for methylene blue was investigated in this study. Methods: With phosphoric acid as activator, the Box-Behnken center combination design was used to optimize the preparation conditions of biochar from Xanthoceras sorbifolia shell. The biochar obtained under the optimal preparation conditions was used to adsorb methylene blue in water. Through investigating the adsorption influencing factors, the adsorption characteristics of biochar on methylene blue were determined, and combined with the analysis of kinetic, the adsorption mechanism was discussed. Results: The optimum technological conditions for preparing biochar from Xanthoceras sorbifolia pericarp by phosphoric acid activation were as follows: impregnation ratio （mPericarp powder∶mPhosphoric acid solution） 1∶21, pyrolysis temperature 530 ℃ and pyrolysis time 75 min. The optimal conditions for adsorption of methylene blue in water by sorbent biochar from Xanthoceras sorbifolia shell are as follows: initial pH of solution 12.6, dosage of biochar 1.0 g/L, initial mass concentration of methylene blue 200 mg/L, and adsorption equilibrium time 120 min. The adsorption of Xanthoceras sorbifolia shell biochar on methylene blue in water obeys the quasi second order reaction kinetics. The adsorption process consists of three stages: liquid film diffusion control, pore diffusion control and adsorption desorption equilibrium. Conclusion: Phosphoric acid activation can significantly increase the specific surface area and pore volume of sorbent biochar from Xanthoceras sorbifolia sheell, thereby significantly improving its adsorption capacity for methylene blue.
Abstract: Objective: A process was developed for the purification of bran polyphenols from HPD 600 macroporous resin. The purity and antioxidant activity of the extracts were analyzed before and after purification, and the polyphenol fractions in the purified products were characterized. Methods: The bound polyphenols in wheat bran were extracted by alkali hydrolysis, and the dynamic adsorption-desorption conditions of the macroporous resin were optimized by single-factor test to determine the optimal purification process. The antioxidant activity fraction was determined by ABTS and DPPH radical scavenging rate. The characterization of the polyphenol fraction in the purified product was completed by UPLC-MS/MS. Results: Under optimal process conditions, the purity of the polyphenols and the antioxidant activity of the purified product were significantly increased. The purified products contained mainly nine polyphenolic compounds, in order of retention time: p-hydroxybenzoic acid, caffeic acid, vanillin, p-coumaric acid, trans-ferulic acid and salicylic acid. Conclusion: The macroporous resin purification process is effective in enriching bran polyphenols and the resulting purified product has a significantly higher antioxidant capacity, while maintaining the richness of the polyphenolic species.
Abstract: This review introduced the classification, structure and physical and chemical properties of dietary fiber, and summarized the relevant research literature on the modification methods and physicochemical properties of dietary fiber at home and abroad in recent years. The development direction of the physicochemical properties of dietary fiber and its modification methods were also prospected, in order to provide a theoretical reference for its efficient and comprehensive utilization.
Abstract: Objective:The flavor formation process of stewed pork was investigated in this study. Methods: Electronic nose and gas-phase mass spectrometry (GC-MS) techniques were used to compare the key processes such as bleaching, frying, stewing and addition of sauces during the processing of stewed pork, and to analyze the changes of flavor compounds. Results: The results of electronic nose measurement were consistent with the results of gas chromatography analysis. The flavor content of raw pork and sauces was the highest, and the flavor substances decreased in the blanching, frying and stewing stages. However, the characte-ristic flavor substances were formed continuously. A total of 148 compounds were detected by GC-MS, including 39, 32, 23, 20, 38, and 65 compounds in raw pork, blanched, fryed, stewed and finished products and sauces, respectively, which mainly produced aldehydes and ketones, esters and alcohols, heterocyclic compounds, and aromatic hydrocarbons and their derivatives. The characteristic flavors of finished products were hexanal, benzaldehyde, 1-octen-3-ol, cinnamaldehyde, 2-pentylfuran, 2-acetyl pyrrole, 2,3-dimethyl-5-ethylpyrazine, etc. The content of acetoin was higher in the pre-preparation stage of stewed pork, while methoxy-phenyl-Oxime stayed high in all of the processes. Conclusion: The electronic nose technique can be used to detect the changes of flavor substances in different processing stages of stewed pork, but the specific substance changes need to be determined and analyzed by GC-MS.
Abstract: Objective:A method based on the high resolution mass spectrometry library and diagnostic ratio of characteristic components was established to identify the illegally added psoraleae fructus in wine and tea.Methods:High resolution mass spectrometry library of psoraleae fructus was constructed by high performance liquid chromatography quadrupole time of flight mass spectrometry (HPLC-TOF-MS) for preliminary screening. Combined with the diagnostic ratio method of the characteristic components by, high performance liquid chromatography, psoraleae fructus in different 20 samples of mixed wine and mixed tea from different picking time and origin was tested and analyzed The diagnostic ratio of characteristic component peak area, which was less affected by the origin, picking time and processing technology, has no significant difference between different matrix groups, and was selected as the identification index.Results:High resolution mass spectrometry library of psoraleae fructus was established by high performance liquid chromatography quadrupole time of flight mass spectrometry (HPLC-TOF-MS) for preliminary screening. Corylia/psoralen and psoralen/isopsoralen were selected as the two characteristic groups. The box diagram was drawn to determine that the non-abnormal value range of Corylia/Psoralen was 0.061~0.115, and the non-abnormal value range of Psoralen/Isopsoralen was 1.14~1.68. The established screening and confirmatory methods were validated by commercial samples.Conclusion:The method is simple and efficient, which provides technical support for cracking down on illegal addition of psoraleae fructus in wine and tea.
Abstract: Objective:Improve the quality of dried okra products.Methods:The rehydration ratio, shrinkage rate, vitamin C content, drying time and sensory score were used to analyze the effects of different pretreatment methods on the quality of dried okra products, and the coefficient of variation method was used for comprehensive weighted evaluation.Results:The results showed that blanching and ultrasonic pretreatment can significantly increase the rehydration ratio of the dried sample (P＜0.05). The shrinkage rate was most affected by blanching. The vitamin C content of the pretreatment group was lower than that of the control group, and the ultrasound treatment group had the least loss. The blanching and ultrasonic pretreatment can shorten the drying time, and sensory scores of samples pretreated by ultrasound and color protection were significantly higher than those pretreated by blanching (P＜0.05). The comprehensive evaluation by the coefficient of variation method showed that the quality of the okra pretreated by ultrasonic was the best, followed by the color protection treatment, and the blanching treatment had the lowest comprehensive score. When the ultrasonic pretreatment temperature was 20 ℃, the comprehensive score of the dried sample obtained was the highest, which was 0.907.Conclusion:The research showed that the ultrasonic pretreatment was a better pretreatment method with hot air drying of okra.
Abstract: Objective: To accurately distinguish intact peanut, nut damaged peanut and epidermis damaged peanut. Methods: A peanut seed integrity detection scheme based on deep learning convolution neural network (CNN) was proposed. The peanut seed color selection system was established and a peanut seed image database was also established; The improved density peak clustering (DPC) algorithm was used to adaptively compress the CNN convolution kernel to effectively balance the network depth and operation efficiency; The improved sparrow search algorithm was used to optimize the CNN super parameter configuration and network structure, and the CNN model suitable for peanut grain integrity detection was obtained. Results: Compared with other detection methods, this scheme improved the recognition accuracy by about 5.41%~13.92%, and the detection time of single image of peanut grain was shortened by about 16.9%. Conclusion: This method effectively improves the accuracy and real-time of peanut grain integrity detection.
Abstract: The new extraction technologies of citrus flavonoids in recent five years were reviewed, including low eutectic solvent extraction, subcritical fluid extraction and magnetic molecular blot selective extraction.the bioactivities and mechanisms of citrus flavonoids, such as antioxidant, anti-inflammatory, antibacterial, anti-obesity, anti-diabetes, anti-cancer, intestinal protection, cardiovascular protection, liver protection and neuroprotection, were also expounded, and suggestions for further study of citrus flavonoids were proposed.
Abstract: Based on the scientific theory of modern nutrition and functional food science, this paper uses biotechnology and information digital technology to establish a more precise, flexible, integrated and digital functional food research and development system-flexible precise nutrition intervention system (FPNIS) which improves the shortcomings of the two common functional food research and development models that are based on traditional Chinese herbal medicines or simple ingredient dietary supplements. Through the establishment of FPNIS, provide a new way to explore the research and development of efficient and precise functional food, and analyze its trend.
Abstract: Objective: This study aimed to investigate the microbial succession and the changes of volatile flavor substances in traditional fermented fish. Methods: Traditional microbial counting methods, high-throughput sequencing, gas chromatography-mass spectrometry（GC-MS） were applied to explore the effects of different fermentation times of traditional fermented fish （0~180 d） on microflora changes and the volatile flavor compounds during the processing of the solid fermentation process of traditional fermented fish as well as on the correlation between them. Results: The results showed that the main dominant bacterial genera included Staphylococcus, Lactobacillus, etc. That there were 69 volatile flavor components in fermentation process, mainly including acids, alcohols, aldehydes, ketones, N compound；benzene compound, alkyl aromatic compound, esters. and their types and contents changed with the fermentation time. The correlation analysis results showed that Staphylococcus was positively correlated with N-containing compounds and negatively correlated with alcohols. Lactobacillus was significant positively correlated with nonanoic acid,1-octen-3-ol, nonanal, tetradecanal, 2, 4-dimethyl styrene, decyl ene, ethyl caproate （0.01＜P＜0.05）. And negatively correlated with heptenic acid, 3-methylbutyric acid, 2, 3-butanediol, 2, 6-di-tert-butyl p-cresol, Copaene and myristic ethyl ester. Although the relative abundance of microorganisms such as Citrobacter, Turbulella, Psychrobacter, Acinetobacter, Oceanospirillales and Flavobacteria was relatively low in the whole fermentation process, there was also an obvious correlation with the formation of flavor substances. Conclusion: The microbial community and volatile flavor compounds have a series of changes with fermentation time, and there is a significant correlation between them.
Abstract: Objective: This study aimed to select a suitable drying method for preserved yellow peach. Methods: Preserved yellow peach was prepared by hot air drying (HAD), microwave-hot air drying (MHD) and vacuum freeze drying (VFD). Its physical properties, nutritional components, sensory and aroma indexes were studied. Results: Compared with traditional HAD, the efficiency of MHD was increased by 56.1%, and the preserved fruit was significantly better than HAD in color, nutritional composition, sensory evaluation, aroma components and content; The preserved yellow peach fruit by VFD has the best color, the strongest rehydration, the best tissue structure integrity of the product, the highest contents of nutrients vitamin C, and total phenol and titratable acid, and the highest sensory score is 91.58. It has the most aroma components and contents, and uniquely has two aroma components: 2-hexenol and trans-2-hexenal. Conclusion: Compared with HAD, the preserved yellow peach fruit prepared by MHD is better in all aspects, and MHD is more suitable for the production of common preserved yellow peach fruit. The quality of preserved yellow peach fruit prepared by VFD is the best. However, due to the high-energy and -cost consumption, it is recommended to produce high-quality preserved fruit.
Abstract: Objective: The effects of superfine chestnut powder on sponge cake quality was studied, aiming to provide a certain theoretical reference for improving the quality of bakery food. Methods: To explore the superfine chestnut powder adding amount on the sponge cake texture, sensory, baking, aging characteristics and nutritional quality, different contents of superfine chestnut powder were added during the making process of sponge cake. Results: The hardness, elasticity, chewiness and specific volume of cake had no significant change compared with the control group when chestnut powder was added less than 10%. The addition of chestnut powder could reduce the brightness and yellowness while increase the redness of the cake, and the effect on the color of the cake core was greater than that on the surface. Adding chestnut powder could reduce the cake bakingloss, aging enthalpy value and increase its nutritional quality. When the content of chestnut powder was 5%, the cake had the best color, shape, taste, hardness and overall preference. In general, the appropriate amount of superfine chestnut powder was 5%~10%. Conclusion: The addition of superfine chestnut powder endowed the sponge cake with better quality.
Abstract: In order to study the factors that the influence of the cassava stalk toughness. Orthogonal experiments were used to test cassava stalk with MW-4 universal testing machine And the influencing factors were selected, for cassava stalk variety, placed time, and colliding parts. The results show that: effect of varieties on the impact energy is the largest, while, the impact energy was the smallest when the variety is SC6, placed for 12 days, and the the upper part collision site. Effect of varieties A on the impact toughness is the largest. The impact toughness is the smallest when the variety is SC6, the moisture content is placed for 0 days, and lower part collision position. The average impact energy and impact toughness of the lower part of cassava stalk are higher than the upper part.
Abstract: Introduces a electrostatic potential test system designed by LabVIEW, which had been done 7 electrostatic potential test experiments for 6 factors of electrostatic potential on the surface of electrostatic stalk extractors frictional roller, and improve overall electrostatic potential of the optimal solution is given. When drum material is synthetic rubber, roller rotation speed is 38 r/min, counter weight is 10.5 kg, friction material is silk, the humidity is controlled below 60%, the overall electrostatic potential and the stalk rate is the highest.
Abstract: There were two methods to detect the plasticizers of red wine. The first one was a traditional method(GC-MS) and another one was a new method-ELISA kit. An improved pre-processing of GC-MS and the comparative analysis of the two methods was used to find a novel detection method. The results: there was a little difference for the rate of plasticizer extraction with different pre-treatment. And DIBP, DBP, DEHP were detected. The GC-MS method demonstrated high precision and recovery. The GC-MS method was a excellent method to detect the plasticizers of red wine. The detection results of ELISA kit were 3.4 to 5.5 times larger than the GC-MS method. It was enough for ELISA kit as a rapid detection method of the plasticizers of red wine.
Abstract: A method was developed using ICP-AES for the simultaneous determination on the content of trace heavy metals including Na, Mg, Al, K, etc in 3 spieces of jujube of Xin Jiang district. The correlation index of method was greater than 0.998; Determination of elements in addition to the individual value, RSD is less than 5%. The results showed that: xinjiang jujube had rich mineral elements content, which especially in K (＞12 277 μg/g), Ca (＞785 μg/g), Mg (＞ 646 μg/g), Na (425 μg/g), Al (＞179 μg/g), Fe (＞22 μg/g) content is higher, the K and Fe content of Aksu jun jujube and Hami jujube were higher than other areas and varieties of jujube.
Abstract: The sample was purifid by solid phase extraction column. A simple, fast, accurate method for determination of Imibenconazole in fruits and vegetables was developed by ultra high performance liquid chromatography-tandem quadrupole mass spectrometry (UPLC—MS—MS). The linear range of the method is from 1.0 μg/L to 100 μg/L ，and the correlation coefficients were 0.998 7～0.999 6, and the detection limit is 1.0 μg/kg. The proposed method has high sensitivity and good reproducibility for determining Imibenconazole.
Abstract: The reasonability using near-infrared spectra (NIRS) for detection of melamine in liquid milk were studied. NIRS of samples were obtained by Fourier Transform Infrared Spectroscopy(FTIR) spectrometer, samples of liquid milk with adding melamine were analyzed while characteristic signals were extracted by wavelet transform and principal component analysis. Quantitative analysis was taken by General the Regression Neural Network(GRNN) for the diffuse reflectance spectroscopy of liquid milk adding melamine first. The result is not satisfactory enough that when concentration of melamine is lower than 0.05%, the R2 of predict model is only 0.567. Qualitative discrimination by support vector machine was carried out later. The results showed that the model has a very good discriminate ability of the spectrum. The accuracy of the test set was 94.44%. Overall, NIRS combined with appropriate chemometrics methods is a feasible way to take qualitative discrimination of liquid milk whether or not adding melamine.
Abstract: The unsafe factors in the products of traditional craft baked betel nuts, betel improved oven baked dry and edible betel nut pieces were analyzed. The results showed that benzopyrene were the major effect factors on the food safety of Betel nut products. And the baked methods of betel nuts had greatly influence on the content of benzopyren. An overdose of benzopyrene was found in these baked betel nuts baked by traditional ways, such as traditional smoked roasting ovens, traditional hot wind roasting ovens. However, taking the baked Betel nuts as materials to manufacture products, the content of benzopyrene in these was within the safe limit level. Sulfur dioxide and nitrite was detected in commodity betel, but it's content within the relevant national control standards, and not enough to cause food safety problems.
Abstract: Recently，the beef and mutton industrialization is developing rapidlyin Xilingol district of Inner Mongolia. To have a better understanding of sanitary quality of Xilingol beef and mutton, tests of bacterial colony, fecal coliform and pathogenic bacteria were conducted on 160 pieces of Xilingol beef and mutton samples. The results showed that the qualified rate of bacterial colony and fecal coliform were 76.25% and 77.18%, and the detection rate of pathogenic bacteria was 5.63%. The data provided theory evidence for improving Xilingol beef and mutton sanitary quality in the future.
Abstract: To investigate the accumulation and pollution in Zn, Cu, Pb and Cd of the leaf vegetable by Changsha section of Xiangjiang River, three kinds of vegetable were collected and detected. The results showed that: the contents of these four heavy-metal elements in vegetable samples ranked from greatest to least was as follows: Zn＞Cu＞Pb＞Cd; Brassica chinensis L. had strong accumulation ability in Cu, Pb and Cd; 26.67% samples were heavy contaminated.
Abstract: To investigate the distribution of serotypes, genetic relativity and epidemiological characteristic of Listeria monocytogenes (LM). 22 LM strains isolated from Guangzhou and Xiamen were investigated by ERIC-PCR and Sau-PCR. Results of ERIC-PCR showed that these strains were distributed in 8 patterns (a-h). The main pattern was pattern h, and the number of strains was 8. Genotyping using Sau-PCR showed that all tested strains were grouped into 7 clusters (A-G). These results indicated the genetic relativity and epidemiological characteristic of different LM food-borne isolates.
Abstract: This research according to the quality requirements of massage base oil as evaluation indexes, combining with free radical clearance, oxidation resistance and other indicators, compared the decolorizing technology's influence on the quality of sesame oil. And compare oils which have done in-depth research in the field of cosmetic skin care, such as olive oil, grape seed oil, wheat germ oil. That results showed that the decoloring process of sesame oil improve the oxidation resistance and the ability of scavenging free radicals significantly. In general, sesame oil skin care is better than other several kinds of vegetable oil which used as massage base oil commonly.
Abstract: The best adsorption conditions of the attapulgite on Lactobacillus cells were optimized. Different kinds and concentrations of acids and alkalis were used to pretreat the attapulgite, the results showed that 1 mol/L H3PO4 was the best. In pH 6, 0.4 mol/L phosphate buffer system, adsorption of attapulgite on Lactobacillus cells basically completed in 60 min, and reached to the adsorption equilibrium. Adsorption of attapulgite on Lactobacillus cells could well fit the Langmuir adsorption isotherm equation. With the increase of temperature, the equilibrium adsorption of attapulgite on Lactobacillus cells increased higher, which was an endothermic process. When Lactobacillus cells concentration increases, the equilibrium adsorption capacity was also increasing. The adsorption process belonged to the preferential adsorption.
Abstract: The physical properties test of the crunchy rice candy was carried out with a texture analyzer under compression mode. The crispness of the crunchy rice candy was tested using the sensory evaluation method and was adopted the compression mode a texture analyzer. Spss statistical analysis software was applied to the data of crispness sensory eveluation and texture test. Subsequently, the forecast model was constructed for the crunchy rice candy crispness by analyzing the correlation between the data of crispness sensory eveluation and texture test. The results showed that:the best testing speed was 1.0 mm/s, the compression deform deformation was 50%.The Peak Positive Force（X1）, Positive Area（X2）,Area To Positive Peak（X3）, Linear Distance（X4）data were very significantly correlated with the crispness of the crunchy rice candy. The prediction model was Y=-4.130+0.241X1-0.101X2-0.487X3+0.128X4, the correlation coefficient was 0.977, P＜0.05, and the model can predict the crispness of the crunchy rice candy.
Abstract: The changes of microstructure of cooked chicken breast treated by ultra-high pressure treatment(UHP) were observed, for the further study of UHP on cooked chicken breast. Results indicated that the gap between the muscle fibers decreased, endomysial disappeared gradually, and the structure of muscle fibers was more closely. Meanwhile, muscle fiber diameter and rate of juice leakage increase could be resulted from UHP significantly. Myofibril was fragmented and gelated obviously when the pressure was over 400 MPa. The microstructure of cooked chicken breast treated by UHP could explain the changes of jucie leakage, texture and edible quality.
Abstract: Chicken was cooked by three methods which were frying, braising and stewing, to compare the changes of volatile aroma and texture of cooking chicken. Results showed that after cooking chicken sensory quality characteristics changed dramatically. Aldehydes content was significantly higher than alcohols and alkanes in volatile components of fresh meat. However, the volatile compositions of cooking chicken were mainly aldehydes and alkane substances, and aldehydes and alcohols content decreased significantly, with the order of decreasing degree: fried > braised >stewed; But alkane matter content increased significantly with the same order of increasing degree as above. After cooking, some new macromolecules were detected too. Of the three cooking ways, the hardness and chewiness of fried chicken were the lowest, but elasticity and cohesiveness were the highest; the hardness and chewiness of braised chicken tended to be the highest, but elasticity and cohesiveness were the lowest.
Abstract: The nutrient compositions’ change of green beans, black beans, soybean were studied during sprouting in order to provide experimental basis for the sprouting soybean food production and processing. Control soybean germination conditions by using a certain temperature and humidity, regular sampling and assay sprouted soybean’s crude protein, crude fat, reducing sugar, Vc and isoflavone’s content. The results show that: the protein content of green beans, soybean and black beans after seven days’ germination increased by 24.03%, 24.28% and 22.88% respectively than after one day’s germination, the reducing sugar content increased by 129.06%, 127.17% and 125.73% respectively; the Vc content increased by 831.37%, 663.97% and 807.07%; the crude fat content reduced by 37.28%, 35.68.28% and 36.69% respectively. The isoflavone content of three kinds of soybeans reached the maximum value after four days’ germination, the black soybean’s isoflavone was 0.531% and was the highest.
Abstract: The pH value, intermediate (A294nm), browning intensity (A420nm), free amino group content and antioxidant activity as detection index. The effect of temperature(100 ℃, 120 ℃) on Maillard reaction and antioxidant activity of the Maillard reaction products(MRPs) derived from yellow stripe trevally(Selaroides leptolepis) fish protein hydrolysates was investigated. The results were as follows: when reaction temperature was 120 ℃, the pH value, intermediate (A294nm), browning intensity (A420nm) and free amino group content of the systems during the Maillard reaction were more significant, and the reducing power and DPPH radical scavenging activity of MRPs were enhanced greatly, however, the hydroxyl radical scavenging activity and Fe2+ chelating activity of MRPs were decreased significantly, compared with 100 ℃.
Abstract: Releasing regular of flavor compounds during enzymolysis of mussel (Mytilus edulis) protein and the structure of seafood flavor peptides were investigated with amino acid analysis, ultrafiltration, gelchromatography, RP—HPLC, and UHR—Q—TOF. The results indicated that, during enzymolysis, molecular weight of peptides reduced. The amount of free flavor amino acid and TMA increased. The amount of peptidyl flavor amino acids increased then decreased. It’s advantageous for peptides with low molecular weight to be released at low pH conditions. The total carbohydrate varied little. The total acid reached the maximum in 1 h and at 50℃, respectively. Under the conditions that enzymolysis time of 2 h, enzymolysis temperature of 50 ℃ and enzymolysis pH of 6.5, the percentage of low molecular weight peptides, total acid, total carbohydrate, and flavor amino acid were in fairly high level. The flavor peptides form mussel (Mytilus edulis) were determinated as peptides in a low molecular weight below 1 kDa, with unique amino acid sequences of Cys-Ser-Val-Gln-Asp-Gln or Gln-Ala-Val-Asn-Phe-Thr, and taste threshold of 0.1 mg/mL.
Abstract: Chicken soup and mixed samples with artificial blending were tested by electronic tongue and the response signals were analyzed by principal component analysis (PCA), discriminant factor analysis (DFA) and partial least-squares analysis (PLS). Chicken soup and artificial blended soup were successfully identified by electronic tongue. Moreover, a high regression coefficient, R2=0.958 71, between instrumental response signal and mixed ratio of chicken soup and artificial blended soup was found for the established PLS model with a prediction error below 15%.This study demonstrates that electronic tongue is applicable for soup discrimination.
Abstract: Effect of the different ratio of succinic acid to cigarettes on the volatile substances formed in the process of pyrolysis was studied to investigate the influence mechamism of succinic acid on the decreasing flavor of cigarettes by the technologies of online Pyrolysis-Gas Chromatography/Mass Spectrometry. It was shown that free nicotine would decrease substancially while mono-protonated and diprotonated nicotine would increase obviously with increasing succinic acid. With the addition of 1%, 2% and 3% of succinic acid to cigarettes, the total volatile substances formed in the process of pyrolysis of cigarettes was reduced by about 23 percent, while low molecular weight carbonyls and furans down by 26%～30% and alkenes down by 23%～26%. The quantity of carbohydrates pyrolysates and volatile Maillard reaction’s products fell by 30 percent, particularly DDMP and 5-hydroxymethyl furfural decreased sharply, down by 84.1% and 75.6% respectively when the usage of succinic acid reached 3%. The total phenols were reduced by 29.5%, 37.0% and 37.3% respectively while key aroma chemicals fell by 31.4%, 36.8% and 36.8% respectively, when 1%, 2% and 3% of succinic acid were added to cigarettes. According to the changing conditions of the formed volatile substances, the influence mechanism of succinic acid on the suppressing flavor of cigarettes was deduced.
期刊介绍
Editor-in-Chief：ZHU Bei-wei
Address：Changsha University of Science and Techonology NO.960 2nd section, Wanjiali RD(S)
