Abstract:This study was conducted to evaluate the effect of new propylene glycol esters emulsifier on the specific gravity, viscosity, rheology, microstructure of batter and baking characteristics of low-fat cake. The results showed that propylene glycol esters increased the surface tension of oil and promoted changes in fat structure to the α crystalline form as observed by XRD. The small bubbles were protected by propylene glycol esters from defoaming caused by oil. The number of bubbles increased by 1.87 times. Propylene glycol ester significantly increased the specific volume and decreased hardness of low-fat cake.

Abstract:To avoid various issues brought by high-sugar intake from sponge cake, we explored the feasibility of completely replacing sucrose in sponge cake with four kinds of functional oligosaccharides, whose effects on the batter and the baking quality were compared with each other. The results showed that the batters of isomaltooligosaccharide, fructooligosaccharide, and galactooligosaccharide were similar to that of the sucrose group, illustrating promises of introducing healthier formula without sacrificing product quality. The sponge cakes of the three substitute candidates maintained good taste after three-day storage. However, the fourth candidate, inulin, was too strong in water absorption, resulting in low quality of sponge cakes in the sense of smaller sizes, higher hardness, and powder-like taste, usually regarded as not desirable.

Abstract:In order to obtain starter cultures with good performance for fermented rice cake, lactic acid bacteria strains and yeast strains were isolated from traditional fermented rice slurry. Through the investigation of colonies, morphological characteristics and growth properties one strain of lactic acid bacteria and two strains of yeasts were screened. According to the 16S rDNA and 26S rDNA sequence analysis, they were identifided as Lactobacillus plantarum, Candida humilis and Saccharomyces cerevisiae. Remixing three superior fermentation strains in fermented rice cake, the optimum bacteria ratio was determined by analyzing the sensory quality and texture characteristics of the fermented products. The results showed that when the proportion of actobacillus plantarum, Saccharomyces cerevisiae and Candida humilis was 136, the sensory quality and texture property of fermented rice cake were the best and 29 kinds of volatile flavor substances were detected by GC-MS. Five kinds of flavor substances were detected together with the commercial rice cake and the double bacteria compound starter, such as phenylacetaldehyde, benzaldehyde, phenylethyl alcohol, tetradecane and ethyl palmitate. And 12 kinds of unique flavor substances were detected. Among them, nine of which were esters. The rice cake produced by the fermentation of the compound starter had better quality, which was expected to be applied to the fermentation production of rice cake.

Abstract:In order to screen yeast strains suitable for brewing sugarcane wine, the commonly used commercial fruit wine yeast strains KD, DV10, Q23, EC1118, Angel yeast and H7Y7 were selected as the tested yeast strains. Sugarcane wine was fermented by using sugarcane Chuanzhe 17 as raw material, and the sugar consumption, alcohol content and clarity of the fermentation liquid were analyzed. By comparing the fermentation characteristics of different yeasts found that EC1118 had the strongest sugar consumption and wine production capacity, and it also had the lowest alcohol production. The H7Y7 strain fermented sugarcane wine with the highest ester content, which is 3 to 6 folds than that of other strains. Using Angel yeast for sugarcane wine fermentation was easiest to clarify, but the methanol content of Angel yeast was 5 folds than that of other yeasts. Sensory scores showed that the sensory evaluation scores of different yeast fermented sugarcane wine were H7Y7>EC1118>DV10>Angel yeast>Q23>KD. Research indicates that The EC1118 and H7Y7 yeast strains were more suitable for sugar cane brewing.

Abstract:The Y₆ strain screened from the grape surface was subjected to atmospheric pressure room temperature plasma (ARTP) mutagenesis, and the Saccharomyces cerevisiae strain with strong alcohol production ability, high acid production ability and stable fermentation performance were selected. The single-factor test confirmed that the optimal mutagenesis condition was lethality rate at 98.70% treated for 100 s. The target strain Y₆-8 producing alcohol and producing acid was screened by 2,3,5-triphenyltetrazolium chloride (TTC) method, bromocresol green medium method and Du's tubule, and then its genetic stability was studied. The results showed that the mutagenized strain Y₆-8 was added to the grape juice with the same sugar content, and the alcohol production and acid production capacity of the mutagenized strain were increased by 28.13% and 214.93%, respectively, and the genetic performance was stable.

Abstract:Comparison of musalais wine by two concentration methods and the addition of supplementary materials. The quality and aroma components of four kinds of Musalais were studied and analyzed by QDA. The results showed that the total sugar, reducing sugar, soluble solids, pH, clarity, and bioactivity of frozen concentration group were significantly higher than those of the heat concentration group. Among the four kinds of Musalais, esters were the most abundant, up to 65 kinds of aroma-producing substances. The relative content of esters in frozen concentrated Musalais was the highest, about 48.77% of the total volatile substances. The relative content of esters (36.95%) in heat-concentrated Musalais was slightly lower than that in freeze-concentrated Musalais. The results of QDA statistics showed that cold Musalais had a bright and uniform color, smooth taste, sweet and sour taste, obvious flower and fruit aroma, and long aftertaste. It has the highest sensory evaluation and the best flavor.

Abstract:The effects of different tea polyphenols on the antioxidant and digestive properties of black powder were studied. Taking the DPPH scavenging free radical rate, total reducing power, starch hydrolysis curve as the indicators, discussed the effect of tea polyphenols on the antioxidant and digestive properties of black powder. Research indicates: the addition of tea polyphenols significantly changed the index of black powder (P<0.05), enhanced DPPH free radical scavenging ability, total reducing power, total antioxidant, reduced starch hydrolysis rate. When the amount of tea polyphenols added is 0.040%, the DPPH free radical scavenging ability, total reducing power absorbance and total antioxidant ability of black powdered powder increased by 4.6%, 0.58, 8.83 U/g, respectively. The starch hydrolysis rate of black powder was reduced by 24.98%.

Abstract:In order to develop and improve the utilization of whole grains, the macrogenomics method was used to analyze the structural composition of the whole wheat traditional fermentative dough, and the result shows that the core fermentation genus was Lactobacillaceae Lactobacillus brevis. According to the relevant literature, the flavor substances of whole wheat traditional fermentative dough and commercial fermentative dough were determined. The traditional fermentative dough contains 9 more flavor substances than commercial fermentation and there were also differences in the content, with the hydrocarbon content was showing the highest. It was indicated that the traditional fermentation strain was more conducive to the formation of flavor substances in the whole wheat dough, this was more acceptable to consumers and provided theoretical support for the application of traditional fermentation strains in whole wheat products.

Abstract:In order to analyze the effect of roasted temperature to seed processing on the key aroma components and sensory attributes of camellia oil, compared correlations and differences between aroma components and sensory attributes of hot pressed camellia oil from Hainan and Hunan province, and the volatile compounds of these camellia oils were analyzed by HS-SPME-GC-MS. The ROAV value was calculated to determine the key aroma components. Sensory attributes were analyzed by sensory evaluation and the PLS model was established. The results showed that the most important flavor components in Hainan camellia oil and roasted seed samples of Hunan were (E)-2-nonenal, furfural, phenylacetaldehyde, 2,5-dimethylpyrazine and 3-ethyl-2,5-dimethylpyrazine. As the temperature of roasted seed increased, the yellow score decreased, and the red and brown scores increased significantly; the fresh scent of camellia oil gradually decreased, and the roasted flavor increased. The two kinds of Hainan camellia oil have obvious aroma characteristics of fresh scent and roasted flavor. The roasted seed oil of Hunan have similar roasted flavor when heated by high temperature, but the fresh scent is lower than Hainan camellia oil. It is indicated that the aroma of Hunan camellia oil produced by Hainan traditional high-temperature method has a certain difference between that of Hainan camellia oil. In addition, PLS analysis was used to establish model using key aroma components and sensory attributes, the cross-validated correlation coefficient Q2 was 0.901. It shows that the model has a good prediction ability of aroma quality of hot pressed camellia oil.

Abstract:In order to shorten the germination cycle of brown rice and increase the content of γ-aminobutyric acid (GABA), the effects of aeration coercion, metal ion coercion and double stress treatment on brown rice (Zhen waxy rice 19) were studied. The effects of the content, germination rate and bud length showed that the aeration treatment during the whole germination process can significantly accelerate the germination rate of brown rice and increase the content of GABA in brown rice in the late germination stage. However, it would lead to the buds being too long. Aeration treatment for 9 h can effectively control the bud length of 0.2 cm while increasing GABA content. The coercion germination with calcium ion (Ca²⁺) or aluminum ion (Al³⁺) can greatly increase the content of GABA in germinated brown rice. When the Ca²⁺ solution concentration was 35 mmol/L, the GABA growth rate reached 44.3%. The optimum conditions for the germination of double coercion treatment were as follows: brown rice immersed in 35 mmol/L Ca²⁺ solution for 21 h and then ventilated with 1.5 L/min for 9 h. The germination process lasted for a total of 30 h. Under this condition, the content of γ-aminobutyric acid reached 28.18 mg/100 g which was 64.42% higher than that of normal germination for 36 h and the germination rate increased 2.65%. It can be seen that the double coercion treatment with both aeration and metal ions can significantly increase GABA content and shorten germination cycle.

Abstract:The single factor test was used to analyze the influence of the three factors, sample mass, extraction time and extraction temperature, on the extraction effect of flavor substances from the fermented sausage. And the aroma components from sausages fermented for 6 h and 9 h at 32 ℃ were compared. The results showed that the optimized extraction conditions were the sample mass of 3.0 g when extracted for 50 min at 60 ℃. The 54 and 20 aroma components were respectively identified in sausages fermented for 6 h and 9 h. The esters were found the main volatile components in the sausages fermented for 6 h, while alcohols were the main ones in those fermented for 9 h. Owing to 70.9% of the alcohols content, the peak of the ethanol spectrum was much higher than those of other compounds, which masked the peaks of other compounds. The composition and relative content of aroma components in sausages respectively fermented for 6 h and 9 h had obvious differences. In terms of flavor substances, the effect of 6 h fermentation was better than that of 9 h fermentation.

Abstract:In this study, 4-aminophthalic acid was used to synthesize hapten Dibutyl 4-aminophthalate by esterification reaction, and the synthesized hapten was coupled with keyhole limpet hemocyanin (KLH) by diazotization reaction to prepare the immune antigen and coupled with bovine serum albumin (BSA) to prepare the coating antigen. The New Zealand white rabbits were immunized to obtain the antiserum against dibutyl phthalate. An indirect competitive enzyme-linked immunosorbent assay (ELISA) for dibutyl phthalate was established using the purified antibodies. For the developed ELISA, the IC₅₀ was 40.68 μg/L and the limit of detection was 1.98 μg/L. The method was applied to detect liquor, milk and edible oil samples, and the recoveries ranged from 84.57% to 102.40%. There was a good correlation (R²=0.990 8) between the this ELISA and gas chromatography-mass spectrometry (GC-MS) for the detection of DBP in the spiked samples. The method established in this study can be applied to the rapid detection of dibutyl phthalate in food.

Abstract:Au-Ag nanoparticles (NPs) varying in size (35~91 nm, Au core 19 nm; 66~127 nm, Au core 43 nm) were synthesized via a typical seed growth method and characterized for their morphology and optical properties. The Au-Ag NPs were then applied as surface-enhanced Raman scattering (SERS) substrates for imidan analysis and the influences of particle size and gold-silver ratio for SERS detection were investigated. The results showed that 42 nm Au-Ag NPs with 19 nm Au core and 78 nm Au-Ag NPs with 43 nm Au core had the highest SERS enhancement effect for imidan standard solutions, and could be used to detect the imidan solution at as low as 0.05 mg/L. However, the SERS enhancement effects of Au-Ag NPs for imidan in apple juice were quite different.The minimum detectable concentrations of imidan in apple juice were 5.0 mg/L and 0.5 mg/L, respectively, with the use of 42 nm Au-Ag NPs and 78 nm Au-Ag NPs as SERS substrates. This study indicated that it is possible for rapid SERS detection of imidan in fruit juices by selecting Au-Ag NPs with suitable particle size and the ratio of Au to Ag.

Abstract:Seven different storage period sausages were selected for nitrite content detection and corresponding spectral data collection，and uses Savitzky-Golary method to preprocess spectral data to reduce the noise of spectral data. Then based on the pre-processed spectral data, 29 characteristic wavelengths were extracted by partial least squares regression coefficient method. Finally, the detection accuracy of the prediction model of nitrite in sausages at characteristic wavelength and full wavelength were analyzed. The results showed that the prediction results of the regression model based on full wavelength were all higher than that based on characteristic wavelength, and the full-wavelength partial least squares regression model was superior to that of the principal component regression model, and the coefficient of determination of the accuracy of the partial least squares regression model was determined. The R² and root mean square errors were 0.982 9 and 0.059 2, respectively. The dissertation studies show that the spectral information at full wavelength is more suitable for the construction of hyperspectral detection model of nitrite content in sausage storage.

Abstract:Based on the principal component analysis, we established F score statistics to reflect comprehensive information about main chemical composition and their ratio and used F score as the characteristic value to characterize the homogeneity of formula tobacco. We detected the near-infrared spectral of tobacco samples with different formula tobacco and founded the near-infrared spectral model of F score by using the partial least square method based on the range of 4 281.2~4 485.6，5 542.4~6 024.5，6 043.8~7 135.3 cm^-1 spectroscopy pretreated by multiplicative signal correction and first-order derivative and Savitzkyt-Golay smoothing. The determinant coefficient of F score model was 0.996, and RMSECV was 0.269. The model was found to have good prediction performance and high prediction accuracy. The F statistics score of tobacco samples could be predicted quickly by NIR, and this provided a rapid and efficient monitoring method of tobacco blending uniformity and a technical guidance to the regulation and control of cigarette homogenization production.

Abstract:Primers, and probes were designed for the conserved sequences of five virulence genes involved in Escherichia coli diarrhea mentioned in the new standard of GB 4789.6—2016 national food safety standard. Four kits of multiple real-time fluorescence PCR were established to detect five diarrhea-causing E. coli simultaneously. The results showed that 12 pairs of virulence genes of the four kits were verified by the standard reserve strains of the five diarrhea-causing E. coli strains. In addition, these 12 pairs of virulence genes only play a role in the specific role of corresponding diarrhea-causing E. coli, and have no amplification curve for common foodborne pathogens. The detection limit of escV, bfpB, stx₁, ipaH and invE genes is 10 CFU/mL, and that of aggR gene is 10² CFU/mL. The detection limit of astA and Pic genes was 10³ CFU /mL. When the concentration of stx₂A, ipaH and stIb genes was less than 10 CFU/mL, a significant “S” type amplification curve could be observed, and the line shape was better. In addition, 40 samples including meat, milk, animal diarrhea, and some artificial contamination samples were tested, and a total of 11 positive samples were found. Consistent with the test results of the new standard 4789.6—2016, The results showed that the four kit methods were simple, specific, sensitive and practical.

Abstract:A ultra-high performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method was established for the determination of female-steroid hormones in brown sugar. Brown sugar samples were dissolved in water, and extracted by acetonitrile, then cleaned-up using an HLB column. The analytes were separated on a ACQUITY UPLC HSS T3 column with acetonitrile-water (containing 2 mmol/L ammonium acetate) as mobile phase by gradient elution. The mass spectrometer was detected in multiple reaction monitoring mode(MRM) using positive-ion and negative-ion electrospray ionizations(ESI), respectively. The quantitative analysis was carried out by external standard method. The results showed that the calibration curves had good linearity for 9 female-steroid hormones in the tested concentration ranges, with correlation coefficients of more than 0.99. The average recoveries at three spiked levels were 92.2%~113.2%, and the precisions expressed as relative standard deviations (RSDs) were 1.6%~6.8%. The limits of detection (LOD) were 0.2~1.0 μg/kg. The method proved to be accurate, rapid, sensitive with repeatability and suitable for rapid detection of female hormone in brown sugar.

Abstract:In this study, QuEChERS technology combined with UPLC-MS/MS was used to detect the active ingredients of 33% λ-cyhalothrin-imidacloprid suspension in citrus. Residue and degradation dynamics of the compound in citrus field residue test was studied for the first time. The residual digestion of λ-cyhalothrin and imidacloprid on whole fruit of citrus accorded with the first-order kinetic relationship, and correlation coefficient was 0.956 0～0.992 3. The half-lives of imidacloprid are 5.5～7.6 d while λ-cyhalothrin are 8.2～9.8 d, final degradation rate is above 92%. The terminal residues indicated that the amounts of final residues was positively correlated with the dosage, the number of application and the interval of harvesting. The residues of the two were mainly distributed in peel, followed by whole fruit and pulp. About 28 days later after the last application, the residues of imidacloprid and λ-cyhalothrin in fruits was lower than the MRL value specified in GB 2763—2016, and dietary risk assessment showed that risks of residues were acceptabled. Therefore, it is recommended that 33% imidacloprid-λ-cyhalothrin suspension should be applied in 1 000-fold dilution (330 mg/kg) and can be applied up to 2 times in one citrus production cycle with 10-days application interval and 28-days harvest interval.

Abstract:In order to improve the accuracy in measurement, the uncertainty of determination of Ca in Areca by atomic absorption spectrophotometer (AAS) was evaluated according to “JJF 1059.1—2012 Evaluation and Expression of Uncertainty in Measurement”. First, a mathematical model of determination of Ca in Areca was established at first. Then, the source of uncertainty was analyzed and the uncertainty components were quantified. Finally, the synthetic uncertainty and expanded uncertainty were calculated. The uncertainties of standard curve fitting and AAS had a greater influence on the expanded uncertainty. When the content of Ca in Areca was 3.16 mg/kg, the expanded uncertainty was 0.04 mg/kg (k=2, P=95%).

Abstract:The nickel contents of jujube collected in 2014 and 2016, and samples from different years, varieties, produce areas were analyzed. Moreover, with the analyzing the gardens of the nickel content, the depth soil and the source of nickel in jujube were determined. The results showed that the nickel contents from the samples collected in 2016 were higher than those collected in 2014. The nickel contents in variety 2 and area 2 were higher than other varieties and areas. The nickel content of 0～20 cm depth soil was the highest, and it declined at the beginning and rised up in late with depth of the soil. Collectedly, all the analyses showed that the nickel contents of jujube from Xinjiang were different by years, varieties and areas, and it was found exogenous.

Abstract:In order to achieve rapid identification of Wolfberry from different geographical origin, an electronic tongue identification method based on Hilbert-Huang transform (HHT)-Linear Discriminant Analysis (LDA) was proposed. Taking the four geographical origins (Ningxia, Xinjiang, Gansu and Qinghai) of wolfberry as experimental materials, the voltammetry electronic tongue was used to collect the “fingerprint” information of different geographical origins, and then the Ensemble empirical modal decomposition (EEMD) was used to carry out the original signal of the electronic tongue. The scale decomposition obtained a set of intrinsic mode functions (IMF), and finally its singular spectral entropy and Hilbert marginal spectrum were collected as feature vectors. On this basis, LDA was used to establish a nonlinear combination prediction model for the production area. The experimental results showed that HHT-LDA was better than the algorithm of Feature Point Extraction (FPE), Principal Component Analysis (PCA) and Discrete Wavelet Transform (DWT). The overall classification accuracy and kappa coefficient of Wolfberry from unknown origin reached 98% and 0.973, respectively, indicating that the model had a good identification performance.

Abstract:Based on the analysis of the forming law and manufacturing technology of butter cake, a new butter cake processing machine body was proposed, consisting of a three-degree-of-freedom manipulator and a four-axis motion platform. In the control system, ARM microcontroller and MCX514 motion control chip were used as the core hardware of the control system. At the software level, FreeRTOS embedded operating system and GRBL numerical control system were used as the software framework of the control system. Through the calibration of the basic coordinate system of the contact three-point handshake, the manipulator and the motion table were cooperated to complete the butter cake processing and shaping.

Abstract:Aiming at the shortcomings of series dexterous hand, a new multi-fingered dexterous hand is designed and analyzed based on the advantage of parallel mechanism. Firstly, according to the method of configuration synthesis, a three-degree-of-freedom parallel finger mechanism is proposed and its kinematics is analyzed. Then, based on the configuration of finger mechanism, a suitable palm is designed and combined into a multi-fingered dexterous hand. Finally, the grasping ability and reachable workspace of the parallel multi-fingered dexterous hand are analyzed and compared with the performance of the series dexterous hand. The results show that the multi-fingered dexterous hand based on parallel mechanism has good motion performance and engineering application prospects.

Abstract:LDPE antioxidant films containing 1% α-tocopherol was prepared, and adjusted the release of α-tocopherol by changing diatomite amount (0%, 1%, 2%, 3%) in the films. Chilled pork was vacuum-packed by these films. Determined the total volatile basic nitrogen (TVB-N), thiobarbituric acid (TBARS), redness value (a^*), juice loss, total bacteria counts, pH value of chilled pork, and the release of α-tocopherol from antioxidation films during the storage. The results showed that compared with the control, the antioxidant film of α-tocopherol significantly delayed the increase of TVB-N and TBARS in chilled pork, reduced the loss of juice and enhanced the color of meat, but had no significant effect on the pH value and the total bacteria counts. In addition, compared with the antioxidant films without diatomite, adding diatomite to regulate the release of α-tocopherol in the films could improve the preservation effect of the antioxidant films on chilled pork. When the additional diatomite was 1%, the preservation effect was the optimal.

Abstract:The gelatin-pullulan composite films were prepared. Then the properties of composite films were determined to provide a direction to evaluate the performance of hard capsules, optimize the ratio between capsule materials， and reduce the brittleness and water vapor permeability (WVP). The compatibility between gelatin and pullulan was characterized by light transmittance, Fourier transform infrared spectroscopy and scanning electron microscopy. The results indicated that it could be used for the blending modification of gelatin hard capsules when the glycerol addition was 10% (dry basis percentage), and the mass ratio between gelatin and pullulan was 91. The WVP of the composite films, prepared by the above conditions, was reduced by 26% compared with that of the gelatin films. The elongation at break was 1.19 times higher than the level of gelatin films in low humidity environment. There was good compatibility between the molecules of gelatin and pullulan in the composite films, which could explain the improvement of mechanical stability, and the reduction of WVP.

Abstract:The relation between the equilibrium moisture content and the water activity of crust filling at 23, 30 and 45 ℃ were studied by gravimetric method. The test data were fitted with some typical moisture absorption models by Matlab. The results showed that the moisture isotherm of crust and filling were both S type model. When the moisture activity was constant, the equilibrium moisture content first increase and then decrease with the increase of temperature, which was different from other foods. The Lewicki model and Peleg were the most suitable for fitting adsorption isotherms of crust and filling when the moisture activity was between 0.35 and 0.90. According to the isothermal hygroscopic characteristic model theory of multi-component food, a combined model was developed to characterize the isothermal hygroscopicity of the rice made wafer.

Abstract:Using low-field NMR, nuclear magnetic imaging and one dimensional frequency coding techniques to study changes in water content and migration of pork longissimus dorsi at -18 ℃ after frozen storage for 0d and 1, 3, 6, 9, 12 and 15 months. Regularity, the changes in TVB-N, TBARS, drop loss, and protein solubility during the storage of pork were determined, and a comprehensive analysis of the correlation between changes in water and quality indicators was performed. The results showed that there were 3 components of water in the longissimus dorsi muscle: T₂₀, T₂₁, and T₂₂. As the time of freezing increased, The T₂₁ component decreased and the T₂₂ component increased. MRI showed that with the extension of time, the water distribution of the sample was uniform from the initial distribution to the strong signal at the edge of the sample, and the signal in the middle was low. With the continued deepening of frozen time, it gradually returned to a uniform state. After 15 months, the final moisture distribution was even. And using one dimensional frequency coding, it was found that the signal quantity (magnitude) of moisture in meat gradually decreased with the prolonged storage time. The correlation analysis showed that: T₂₁ was significantly associated with frozen storage time, TVB-N, TBARS, drop loss rate, and protein solubility (P＜0.05). T₂₂ was significantly associated with frozen storage time and TVB-N (P＜0.01). T₂₂ and TBARS, drop loss rate, protein solubility was significantly related (P＜0.05), T₂₁, T₂₂ and meat quality indicators showed a good correlation.

Abstract:In order to clarify the effect of ice-temperature storage on the quality of grape fruit, the quality of Italian grape was studied under four different storage temperatures: super-ice temperature (-3 ℃ and -2 ℃), ice temperature (-1 ℃) and ordinary low temperature (4 ℃). The results showed that the contents of chlorophyll, titratable acid and vitamin C of Italian grapes stored at -3 ℃ were relatively high, which could maintain the nutritional components of grapes well and help grapes to maintain better color and taste during storage.

Abstract:Based on the alcalase hydrolysis, the grass carp scales gelatin were subjected to two-step enzymatic hydrolysis with trypsin, flavor protease, papain and pepsin respectively, to prepare antioxidant peptides. Results showed that two-step enzymatic hydrolysis could effectively increase the hydrolysis degree and decrease the molecular weight of hydrolysates. The alcalase-trypsin hydrolysates had significant free radical scavenging ability and Fe²⁺ chelating ability. Response surface methodology was performed to optimize the two-step enzymatic hydrolysis conditions, and the optimal enzymatic hydrolysis parameters were as follows: substrate concentration of 100 mg/mL, pH 7.8, hydrolysis temperature of 53 ℃ and hydrolysis time of 50 min. Under this optimal hydrolysis condition, the maximum Fe²⁺ chelating ability was 65.72% and the IC₅₀ value for DPPH·, ·OH and O^-2· were 7.39, 0.68 and 1.84 mg/mL, respectively.

Abstract:The best macroporous adsorption resin was selected by comparing the adsorption effects of six macroporous adsorption resins on Alfalfa Leaf Protein (ALPP), and the adsorption-desorption characteristics of ALPP were studied. The results showed that the best type of macroporous adsorption resin for purifying ALPP was DA201-C. The optimum conditions were as follows: flow rate of sampling was 0.5 mL/min, concentration of sampling was 10 mg/mL, 75% ethanol solution was an eluent, the elution flow rate was 0.5 mL/min and the elution volume was 200 mL. Under these conditions, content of ALPP inceased by 46.95%, content of sugar decreased by 81.88%, content of salt and other impurities decreased by 70.97%. DA201-C macroporous adsorption resin had better purification effect on ALPP.

Abstract:Tea residue protein was modified by wet glucosylation. The optimum modification process of tea residue protein was determined by single factor and response surface design with indicators, including the degree of graft and browning index. Effects of modification on functional properties of protein were analyzed. The results indicated that glucose was the optimal glycosyl donor. When glucosylation reaction was carried out with the ratio of 11 (protein to glucose) at 83.68 ℃ and pH 10.60, the degree of graft was (32.89±0.53)%. By this processing, the increases in solubility, emulsifying capacity and stability, foaming capacity and stability of tea residue protein were 35.78%, 0.415, 10.72%, 29.95% and 3.23%, respectively.

Abstract:The resin suitable for the purification of esculetin from Viola tianshanica Maxim was selected from eight macroporous resins by static adsorption and desorption experiments, and its kinetics and thermodynamics behavior on compound was studied. The result indicated that HPD500 was the optimum material for the adsorption of esculetin. The adsorption dynamic behavior was well described by the pseudo-second-order kinetics equation. The adsorption isotherm data from the thermodynamics behavior were fitted better with Freundlich equation. The thermodynamic parameters were found to be ΔH<0, ΔS<0, and ΔG<0 respectively, so this adsorbing process was a spontaneous exothermic process. The optimal purification conditions of HPD500 on esculetin were as follows: loading concentration 2.593 5 mg/mL, maximum loading adsorption capacity 7.780 5 mg/g resin, adsorption rate 2.0 mL/min, 7 BV deimpurity water, 7 BV 50% ethanol elution, elution rate 2.0 mL/min. Under these conditions, the purity of esculetin was greater than 37% and the recovery rate was greater than 93.0%.

Abstract:In order to explore the effect of salt on the quality of chicken breast meat mince with seaweed powder (Eucheuma spinosum), the effect of different salt amount on such factors as pH value, color, emulsification stability, solubility of salt-soluble protein, cooking loss, freeze-thaw loss, texture, water holding capacity, relaxation time T₂ and microstructure of chicken breast batters was investigated. Its revealed in the result that pH value, L^* and W values decreased significantly with the increase of salt content, a^* value increased followed by decreased reaching the maximum value at 1.5% NaCl. Addition of salt could significantly reduce cooking loss and freeze-thaw loss, and improve water retention. With the increase of salt content, emulsifying stability decreased significantly while solubility of salt-soluble protein increased gradually. Adding salt could improved the texture properties, and reduced the T₂₂ peak area shown by Low field NM. Scanning electron microscopy (SEM) showed that the right amount of salt addition could make mince form smaller holes, and the structure of gel network was more uniform and compact. It can be inferred from the above results that adding seaweed powder can significantly reduce the amount of salt, meanwhile ideal low-salt chicken mince product is obtained.

Abstract:In this study, liquid fermentation method was used to evaluate the effect of two fermentation methods on the quality and safety of Fuyuan sauerkraut by comparing the sensory, physical and chemical indicators and microbial changes of Fuyuan sauerkraut with lactic acid bacteria fermentation and natural fermentation in different periods during the whole storage process. The results showed that compared with natural fermentation, the sensory quality of Fuyuan sauerkraut fermented by lactic acid bacteria was better; the nitrite content was lower and the nitrous peak value appeared earlier, the pH value was lower, and the total acid content was higher; the number of live bacteria in lactic acid bacteria was more, the total number of colonies, molds and yeasts were less; Escherichia coli was not detected. The results of this study showed that the quality and safety of Fuyuan sauerkraut produced by lactic acid bacteria fermentation were better than that of Fuyuan sauerkraut produced by natural fermentation.

Abstract:Exploring the effect of milling degree on rice flour quality is very important to develop rice processing mechanism for suitability. The composition, X-ray diffraction, gelatinization, rheological and gel texture and structure of rice flour under different milling degree were determined. The results suggested that with the milling degree increased, the protein content decreased from (11.24±0.06)% to (7.89±0.27)%, and the amylose content increased from (8.51±0.27)% to (25.93±2.42)%, with the increase of XRD absorption peak of starch. The peak gelatinization viscosity increased from (2 025±169.2) cp to (4 847±140.5) cp, and the gelatinization temperature decreased from (71.82±0.67) ℃to (70.1±0.04) ℃. With the increase of the viscosity and elasticity and the decrease of the fluidity of rice flour paste, the gel microstructure region was found uniformed and compacted well. This indicated that milling could reduce the protein content of rice flour, increase amylose content and promote the gelatinization and short-term aging of rice flour, and the promotion effect was strengthened with the increase of milling degree.

Abstract:Taking two different representative batches (A, B) of the domestic commercial cigarette brand M as raw materials. A static headspace-GC/MS method was established and the datas were collected by the MES automatic control system. Aroma components in two batches of tobacco samples (A and B) were determined. RESULTS A total of 40 core aroma components were detected in two batches of finished cut tobacco, of which batch A contained 34 and batch B contained 37; 3-methyl-1-butanol, 2,6-dimethyl Pyridazine, n-hexadecane, 2-acetylfuran, 2-hexen-1-ol, cis-4-heptenal are undetected components in A, 2-methylpyrazine, isoprene Enol and 2-acetylpyrrole were undetected components in B; the relative total content of aroma substances in B was less than that of aroma substances in sample A, and controlling the temperature of the regain zone at 60 ℃ was favorable to retain the aroma components in the tobacco.

Abstract:The preparation technology of grapefruit essential oil nanocapsules was optimized by complex coacervation and orthogonal design. Nano-sized microcapsule were prepared with gelatin A and sodium alginate as wall materials, grapefruit essential oil as core material and CaCl₂ solution as curing agent. The effects were investigated, including core-wall ratio, ultrasonic time, ultrasonic amplitude and the amount of curing agent on the particle size of microcapsules. The particle size distribution, monomer reaction and thermal stability of grapefruit essential oil nanocapsules were characterized by laser particle size analyzer, Fourier transform infrared spectrometer and thermogravimetric analyzer. The results showed that the optimum preparation process was as follows: core-wall ratio was 12, ultrasonic time was 10 min, ultrasonic amplitude was 10%, and the ratio of curing agent to wall material was 13. Under these conditions, the average particle size of microcapsules was （210.08±10.12） nm, the encapsulation rate was （65.02±1.18）%; PDI was 0.295, the dispersion of the system was good; Zeta potential was -18.4 mV, the microcapsules had negative charge, and the system was stable. Fourier transform infrared spectroscopy showed that the microcapsules contained characteristic peaks of grapefruit essential oil. Thermogravimetric analysis showed that the nano-microcapsules had good thermal sustained release.

Abstract:The use of natural pigments of anthocyanins in the food industry to replace synthetic pigments has become a development trend. Compared to synthetic pigments, however, natural anthocyanin pigments show low stability and easy to lose, during the processing and storage, and reducing the color loss during industrial applications is challenging. This study reviewed the stabilization techniques of anthocyanins in recent years, including the addition of polymeric compounds, copigments, metal ion, and encapsulation techniques, in order to provide guidance for the stabilization application of anthocyanin pigments in the food industry.

Abstract:Summarized several non-thermal processing technologies including cold plasma, high pressure, ultrasonic and irradiation treatment on reducing and eliminating food allergens, which can expose or mask epitopes, change the secondary structure, and destroy non-covalent bonds such as hydrogen bonds and hydrophobic interaction that maintain the spatial structure of sensitizing proteins to affect the allergenicity. In addition, this article also compared their advantages and disadvantages for future development and application.

Abstract:Compared with the ozone gas and water, the ozone ice is easy to store and has a long half-life. Furthermore, ozone stored in the ice will be slowly released with the melting process of ice. Due to these precise characters, ozone ice can be used for long-term sterilization for food preservation. Starting from the progress of ozone production technology, the authors introduce the production of ozone, and the preparation of ozone water, and the application of ozone ice in food preservation.

Abstract:In this revtew, the current research progress on the main nutritional components, bioactive substances and biological activities of pepper seed worldwide were summarized, to provide reference basis and new ideas for its comprehensive utilization.