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 K_cat/K_m of LCK_00027 and LCK_00222 to pyruvate were 6.04×10² L/(mol·s) and 2.28×10⁴ L/(mol·s), respectively. The K_cat/K_m 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 (V_water∶V_acetonitrile 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 pastilles were 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 pastilles were 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 pastilles batch 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.