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: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 screening lactic acid bacteria strains with potential probiotic properties. Methods: Five strains of acid-tolerant lactic acid bacteria were screened from twelve low-salt pickles with salt content ≤6%, identified by 16S rDNA, and their probiotic properties were studied. Results: The five strains were Leuconostoc mesenteroides J2, Lactobacillus paracasei N6, Lactobacillu paraplantarum F8, Weissella cibaria M1 and Weissella cibaria M12. Among them, the relative growth rates of L. paracasei N6, W. cibaria M1 and W. cibaria M12 in pH 4.0 medium were 84.23%, 78.32% and 76.29%, respectively, which had strong acid-tolerant capacity. After digestion with gastric fluid at pH 3.0 and intestinal fluid at pH 8.0, the survival rates were 79.26%, 50.65% and 53.37%, respectively, which had strong tolerance to both artificial gastric fluid and intestinal fluid environments. After cultured in 0.3% bile salt for 8 h, the survival rates were more than 30%, and they had strong bile salt tolerance. The hydrophobic rates and self-aggregation rates were both above 60%, and they had strong hydrophobic and self-aggregating capacity. Conclusion: In this study, three strains of acid-tolerant lactic acid bacteria L. paracasei N6, W. cibaria M1 and W. cibaria M12 with probiotic properties were screened, which could be used in the study of compound probiotics.

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:This study aimed to elucidate the activities of endophytic bacteria and their metabolites of Gastrodia elata BI, and to provide theoretical reference for the development of new natural food antibacterial agents and antioxidants.Methods: The endophyte of fresh G. elata in Qinba area was isolated and purified by tissue homogenization and streaking method. The antibacterial, antioxidant and anti-tumor activities of the extract were determined. Furthermore, molecular biology identification was applied for the highly active strains.Results: In this study, four strains were isolated from the inside of fresh G. elata, among which, endophytic bacteria B1 and B2 have good antibacterial activity against Escherichia coli and Staphylococcus aureus . The inhibition zone diameter of endophytic bacteria B2 against S. aureus was 26.33 mm. The four strains all have good antioxidant activities, among which, the percentage of scavenging DPPH scavenges for endophytic bacteria B2 was as high as 69.13%. Endophytic bacteria strain B2, endophytic bacteria B3, and endophytic bacteria B4 have a potential inhibitory effect on HEK293T cells. Among them, endophytic bacteria B2 showed the highest inhibition rate which was 40.40%. The results of molecular biological identification showed that the endophytic bacteria strain B1 and B2 all belonged to Bacillus velezensis , while, endophytic bacteria B3 was Lelliottia sp., and endophytic bacteria B4 was Rahnella aquatilis .Conclusion: The endophyte of fresh G. elata in Qinba area was isolated and purified had antibacterial activity and antioxidant activity.

Abstract:Objective:This study focused on the analysis and evaluation of the differences in the chemical composition of onions from different origins. Methods:Onions from two main production areas in North and South China (Yunnan and Heilongjiang) were used as raw materials, and the differences in chemical composition content and characteristic chemical composition prostaglandin A1 between the two production areas were analyzed by ultra-high performance liquid chromatography (UHPLC) combined with multivariate statistics. Results:A total of 73 peaks were identified by UHPLC, and the chemical contents of onions from two origins could be distinguished by orthogonal partial least square discriminant analysis (OPLS-DA), combined with VIP values ＞ 1,P＜ 0.05 and S-plot. 0.05 and Splot analysis, and a total of 11 major markers of variation were screened. The PGA1 content of Yunnan onion \[(197.21±63.22) mg/kg\] was significantly higher than that of Heilongjiang onion \[(121.37±43.12) mg/kg\]. Conclusion:There were significant differences in the chemical composition content and PGA1 content of onion between the two origins in Yunnan and Heilongjiang.

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 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: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: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: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:A HPLC method was established for simultaneous determination of formaldehyde, acetaldehyde and acrolein in food contact rubber gaskets.Methods:The migration test was carried out according to GB 5009.156—2016 by using 4% acetic acid aqueous solution, 10% ethanol aqueous solution, 20% ethanol aqueous solution, 50% ethanol aqueous solution and olive oil as food stimulants. After derivatization reaction, the samples were separated on Accucore RP-MS column with acetonitrilewater solution as mobile phase and detected by UV detector.Results:The results showed that the three aldehydes showed good linear relationship in the mass concentration range of 0.05~5.0 mg/L, with the correlation coefficients R≥0.998 3. The detection limits of formaldehyde, acetaldehyde and acrolein were 0.57, 0.62 and 1.68 mg/kg, respectively. The limits of quantification were 0.96, 0.99 and 2.93 mg/kg, respectively. In the range of 1.0~15.0 mg/kg, the recoveries of the three aldehydes were 81.0%~103.3%, respectively. The relative standard deviations were 0.78%~7.05% respectively.Conclusion:This method is suitable for the detection of the migration of aldehydes in food contact rubber gaskets.

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:bjective:The adhesive layer of food processing and conveying pipeline winding and tropical surface adhesive was obtained. Methods:The silicone rubber constitutive model was obtained through rheological test, and POLYFLOW was used to simulate the silicone rubber extrusion flow process. Aiming at the gluing uniformity in the length and width direction of the heating belt, the extrusion test electromechanical system was developed to analyze the flow velocity and volume flow distribution characteristics under different channel outlet shrinkage section length and outlet thickness. The channel outlet structural parameters were optimized, The uniformity of adhesive layer was verified by gluing test, and the outlet structure of runner was iterated. Results:Silicone rubber has the characteristics of shear thinning. Within the set parameters of the extrusion runner structure: the length of the shrinkage section of 5 mm, the mouth thickness of 0.8 mm, and the center of the runner outlet of 3.5 mm away from both sides. The runner structure with linear expansion was the best structural parameter for the uniformity of glue application. Conclusion:Silicone rubber is a pseudoplastic non-Newtonian fluid. The coating uniformity can be improved by linearly expanding the edge thickness at both ends of the runner outlet. The distance between the outlet and the heating belt and the matching of silicone rubber flow rate and winding speed are another key factor affecting the uniformity of gluing.

Abstract:bjective:To compare the performance of cryogenic refrigeration system using LNG wasted cold and ammonia cooling.Methods:The thermodynamic and economic models of the two systems were established by MATLAB. Under the basic parameters, the working medium concentration suitable for LNG low-temperature refrigeration system was selected, and the cold storage temperature and refrigeration capacity were changed respectively. The thermal economy of the two systems was compared and analyzed.Results:With the increase of ethylene glycol concentration, LNG mass flow, system power consumption and cold storage capacity increased, COP decreased, but ethylene glycol mass flow remained unchanged; With the increase of cold storage temperature, the system COP increased, while the working medium mass flow and power consumption decrease. Similarly, with the increase of refrigeration capacity, the mass flow and power consumption increase, while the COP of ammonia low-temperature refrigeration system remained unchanged and the COP of LNG low-temperature refrigeration system increased. In the range of 5~20 kW, the COP of LNG low-temperature refrigeration system was lower than that of ammonia low-temperature refrigeration system, and the opposite was true in the range of 20~30 kW. The comparison of economic performance showed that the investment cost of LNG cryogenic refrigeration system was much lower than that of ammonia cryogenic refrigeration system.Conclusion:Under the same working conditions, the thermodynamic and economic performance of the low-temperature refrigeration system using LNG wasted cold is better than that of the traditional ammonia low-temperature refrigeration system.

Abstract:Objective:In order to effectively improve or eliminate as much as possible in the refrigeration system, the uneven distribution of gas-liquid two-phase refrigerant in the evaporator leads to the performance decline of the refrigeration system. Methods:The adopts CFD numerical simulation method was used to establish the physical model of rectifier nozzle type distributor and mathematical model of gas-liquid two-phase flow, based on the mixture model in multiphase flow model, which simulated the phase distribution and the degree of gas-liquid two-phase separation inside this distributor,. Then the influence of inlet conditions (inlet flow rate and mass flow fraction of gas) on the uniformity of diverter distribution was analyzed. Results:The results showed that when the inlet flow rate was 1 m/s and the mass flow fraction of gas was 0.2, the flow pattern gradually stabilizes and a uniform annular flow could be formed. Under the control of these conditions, the overall unevenness of the distributor reached the minimum value and had the best effect of liquid separation. Conclusion:On the basis of optimizing the structure of the distributor, the flow pattern can be further adjusted by adjusting the inlet condition to the best, and the symmetrical annular flow can be formed to realize uniform liquid separation.

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:In order to explore the effect of step-down relative humidity drying strategy on the drying characteristics of agricultural products.Methods:Yam slices were selected as the object. The effects of constant humidity drying (relative humidity 15%, 25%, 35%, 45%) and step-down relative humidity drying (relative humidity 45% in the first stage for different times of 10, 20, 30, 60 min and relative humidity 20% in the second stage) on the drying characteristics of yam slices were studied at 60 ℃; The multi-field coupling model was constructed for the simulation of heat and mass transfer; The rehydration ratio and microstructure of the dried product were also measured.Results:① During constant humidity drying, the drying rate decreased with the increase of relative humidity; However, the drying time of step-down relative humidity drying (45% relative humidity maintained for 20 min and then decreased to 15%) was 8.3% shorter than that of constant humidity drying (relative humidity 15%). ② The drying rate of yam slices generally increased first and then decreased, The fitting results of drying model showed that it was accurate to describe the changing process of moisture and mass transfer. ③ The rehydration ratio increased first and then decreased with the increase of relative humidity; Under special drying condition of step-down relative humidity drying strategy (relative humidity 45% kept for 20 min and then decreased to 15%), the yam slices showed honeycomb porous structure, which was good for the mass transfer. Under this condition, the maximum rehydration ratio was 6.85 ± 0.05; Under the drying condition of constant humidity strategy (relative humidity is 20%), the microstructure of yam sllices begin to shrink and collapse, which led to a lower rehydration rate.Conclusion:During the process of hot air drying, the multi-field coupling model can significantly shorten the drying time, effectively improve the microstructure of materials and improve the rehydration rate of products; The multi-field coupling model can precisely simulate the heat and mass transfer process in yam slices during hot air drying; The research results can provide theoretical basis and technical support for the application and optimization of step-down relative humidity drying strategy.

Abstract:Objective:Explore the effect of physical sterilization on the freshness of fresh cut yam, and provide reference for fresh-cut fruits and vegetables. Methods:The freshness of UV-C and ultrasonic treatments were studied on skinless Chinese yam segment. Sodium hypochlorite treated and non-sterilization groups were used as control. Results: UV-C and ultrasonic sterilization treatments could significantly slow down the decline rate of the sensory quality of Yam and inhibit the increase of total number of colonies (P≤0.05). On the 13th day of storage, compared with non-sterilization group, the browning index of UV-C treatment decreased by 46.15%, hardness(200.34 N) was significantly higher than other treatment groups (P≤0.05), compared with non-sterilization group the PPO activity of UV-C treatment was decreased by 25.23%, the total number of colonies of UV-C treatment was only 5.48 lg (CFU/g). Conclusion:The sterilization effect of UV-C treatment was significantly better than ultrasonic treatment (P≤0.05), improve the freshness, maintain the shelf-life of 13 days.

Abstract:Objective:To reveal the effect of drying processes on the quality of Gansu purple-spoted peonycorolla tea, and to explain the drying mechanism of different drying processes.Methods:Vacuum freezing-hot air combined drying (FHCD), variable temperature hot air drying (VHD) and vacuum freeze drying (VFD) were used to dry the flowers of peony. The active ingredient (anthocyanin content) and quality attributes (moisture content, shrinkage rate and rehydration) of the purple-spotted peony corolla tea processed by three drying processes were determined, and the energy consumption of the drying processes and sensory characteristics (appearance, tea color, taste, etc.) of corolla tea were compared with three drying processes.Results:the anthocyanin content of the purple-spotted peony corolla tea processed by the above three drying processes were 8.63%, 4.68% and 12.26%, and the rehydration of them were 491.52%, 433.28% and 531.75%, respectively. Compared with VHD, anthocyanin content of the purple-spot peony corolla tea processed by FHCD increased by 3.95%, rehydration of it increased by 58.24%, and shrinkage of it reduced by 13.82%; Compared with VFD, the efficiency of FHCD process doubled, and it's energy consumption reduced by 51.79%. The anthocyanin content of corolla tea was significantly positively correlated with shrinkage rate, rehydration and water content, and the correlation coefficients were 0.749, 0.741 and 0.738, respectively. The color of purple-spotted peony was related to the anthocyanin content. The anthocyanin content rule was: rose red corolla tea＞pink corolla tea＞white corolla tea.Conclusion:The purple-spot peony corolla tea processed by FHCD has high quality, high efficiency and energy saving. The anthocyanin content, moisture content, shrinkage rate and rehydration rate of corolla tea processed by this process were 8.63%, 9.46%, 52.85% and 492.40%, respectively. The test results provide a reference for improving the comprehensive quality and drying process of purple-spotted peony corolla tea.

Abstract:Objective:This study focuses on solving the problems that stem and calyx are mistakenly recognized as defective jujube in the current detection process of jujube.Methods:A method for identifying stem / calyx and defects of dried Hami jujube based on deep learning and image processing was proposed. By improving the depth residual network ResNeXt-50, using the region of interest extraction method and transfer learning technology, TL-ROI-X-ResNeXt-50 classification model was proposed to realize the classification of stem / calyx and defects of dried Hami jujube.Results:Through the comparison of model experiments, the region of interest extraction method and transfer learning technology could reduce the calculation cost of the model and improve the accuracy. The accuracy of model recognition could reached 94.17%.Conclusion:The method can initially meet the production requirements of on-line detection equipment for stem / calyx and defects of dried Hami jujube, and provide theoretical basis and technical reference for the development of rapid nondestructive detection system for stem / calyx and defects of other similar fruits.

Abstract:Objective:In order to explore the effect of heat pump drying temperature on the drying characteristics and quality of persimmon slices;Methods:Taking persimmon as the raw material, the effects of different drying temperatures were compared, on the drying time, drying rate, color, hardness, rehydration rate, tannin content, total sugar, vitamin C and total acid content of dried persimmon slices.Results:when the heat pump drying temperature was 65 ℃, the drying rate was higher and the drying time was shorter. The dried persimmon slices dried at 65 ℃ had bright color, similar to fresh fruit color, good rehydration performance, the lowest hardness, the best taste, the highest content of total acid and vitamin C, and moderate content of total sugar and other nutrients.Conclusion:The drying temperature of 65 ℃ is better than other drying temperatures when using heat pump to dry persimmon slices.

Abstract:Objective:In order to eliminate the large amount of redundant information in near-infrared spectroscopy and to improve the accuracy of pork quality identification, and to establish a method for rapid identification of pork quality.Methods:Principal component analysis was used to reduce the dimensionality of pork spectrum data and the characteristic wavelengths of pork spectrum were selected. The parameters of the support vector machine (SVM) model were optimized by the salp swarm algorithm. Pork quality recognition model was proposed based on an improved support vector machine optimized by salp swarm algorithm.Results:compared with grey wolf optimization algorithm improved SVM (GWO-SVM), grid search algorithm improved SVM (Grid-SVM), particle swarm optimization algorithm improved SVM (PSO-SVM) and SVM, the pork quality recognition model based on SSA-SVM had the highest precision.Conclusion:Pork quality identification model based on PCA and SVM optimized by salp swarm algorithm can effectively improve the accuracy of pork quality identification.

Abstract:Objective:The aim of this work is to obtain the optimal purification process of pigment from Boletus edulis by macroporous resin, and study its antioxidant activity. Methods:Based on the static and dynamic test, the influence of resin type, sample concentration, pH, loading flow ratio, ethanol concentration and elution flow ratio on the adsorption and desorption activity of Boletus edulis pigment were investigated to determine the optimal purification conditions. Then the structure, the DPPH·, ABTS+· and ·OH scavenging activity of the Boletus edulis pigment purified was also evaluated. Results:AB-8 was the most suitable type of macroporous resin and the optimum purification conditions were as follows: the pigment concentration of 1.5 mg/mL, pH of 2.0, the sample flow ratio of 2.0 mg/mL, ethanol concentration of 70% (V/V) and the elution flow ratio of 2.0 mL/min. Under these conditions, the purification efficiency of Boletus edulis pigment was 269%. The IC50 of the final purified product for scavenging DPPH·, ABTS+· and ·OH were (0.081±0.001), (0.017±0.011) and (0.119±0.001) mg/mLrespectively. Especially, the ·OH scavenging ability was higher than VC. Conclusion:AB-8 resin was suitable for separation and purification of Boletus edulis pigment, and the pigment after purification revealed strong antioxidant activity.

Abstract:Objective:This study aimed to optimize the extraction technology of total flavonoids from green tea with Deep Eutectic Solvents (DESs) and evaluate the antioxidant activity of total flavonoids extracted from green tea under optimal conditions.Methods:The extraction rate of total flavonoids was taken as the index, with the ratio of liquid to solid, extraction temperature and extraction time taken as the influencing factors, and the extraction process parameters were optimized by orthogonal test, followed by the antioxidant activity evaluating with DPPH free radical inhibition.Results:The optimal extraction conditions for extraction of total flavonoids from green tea with DESs were 80% acetylcholine-lactic acid solution (acetylcholine∶lactic acid =1∶1), with ratio of liquid to solid 30∶1 (mL/g), extraction at 90 ℃ for 75 min. Under the control of these conditions, the extraction yield of total flavonoids was 1.84%, and the concentra-tion of total flavonoids was 65.8 mg/mL. The research on antioxidant activity showed that in a certain concentration range, the antioxidant activity of total flavonoids extract from green tea was stronger than that of vitamin C.Conclusion:Under the control of the optimal technological conditions, the total flavonoids extracted from green tea with 80% acetylcholine-lactic acid solution as eutectic solvent had certain antioxidant activity.

Abstract:Objective:This study focuses on evaluating the auxiliary blood glucose-lowering function of self-made compound nutritional powder in type 2 diabetic rats.Methods:SD rats were intravenously injected with STZ to construct a pancreatic islet injury type 2 diabetes model. The compound nutritional powder was given by oral gavage at doses of 1.68, 3.35 and 6.70 g/kg for 30 days. Fasting blood glucose and blood glucose were measured after 30 days. Glucose tolerance index to investigate the effect of compound nutrients on STZ rats.Results:The compound nutritional powder was positive for the fasting blood glucose and glucose tolerance indexes of STZ rats; it had no significant effect on the body weight of STZ rats.Conclusion:The compound nutritional powder has an auxiliary function of lowering blood sugar in STZ rats.

Abstract:Objective:This study aimed to investigate the hypoglycemic effect of chrysanthemum polysaccharide on type 2 diabetes (T2DM) rats.Methods:The chrysanthemum polysaccharides were extracted by water extraction and alcohol precipitation. After feeding rats with high-fat and high-sugar feed for 6 weeks, STZ (30 mg/kg·BW) was injected intraperitoneally to establish a T2DM rat model, and records were recorded during the experiment. Rat body weight, food intake, water consumption, fasting blood glucose (FBG) was measured every two weeks, and glucose tolerance (OGTT) test was performed in the last week of the test; the insulin (INS) level was measured by Elisa method, and insulin resistance was calculated Index (HOMA-IR). Determination of total cholesterol (TC), triglycerides (TG), high-density lipoprotein (HDL-C), low-density lipoprotein (LDL-C) levels, as well as the levels of superoxide dismutase (SOD), cystathione (GSH), catalase (CAT), and malondialdehyde (MDA) were detected by Western Blot to detect the expression levels of Nrf2, Keap1, and HO-1.Results:Treatment with chrysanthemum polysaccharides could alleviate the weight loss of T2DM rats, reduce their food intake and water consumption, improve the glucose tolerance of T2DM rats, and reduce INS and HOMA-IR in rats. It could significantly reduce the levels of TC, TG, LDL-C in T2DM rats (P＜0.05), and significantly increase the level of HDL-C (P＜0.05). The levels of SOD, GSH and CAT in T2DM rats increased significantly (P＜0.05), and the level of MDA decreased significantly (P＜0.05). The Nrf2, Keap1, and HO-1 protein levels of T2DM rats treated with chrysanthemum polysaccharides tended to normal protein levels.Conclusion:Chrysanthemum polysaccharide can effectively improve the symptoms of "three more and one less" in T2DM rats, reduce FBG levels, increase OGTT, improve INS levels and HOMA-IR, improve abnormal lipid metabolism and oxidative stress levels in T2DM rats, and through regulation Nrf2/Keap1/HO-1 pathway related proteins play a role in the treatment of T2DM.

Abstract:Objective:Optimized extraction technology of Carum carvi L. essential oil and analyzed the volatile components. Methods:Supercritical carbon dioxide was used to extract essential oil from Carum carvi L. seeds and the volatile components of essential oil were analyzed by gas chromatography-mass spectrometry (GC-MS). Results:The suitable extraction conditions of supercritical carbon dioxide were: temperature of extraction kettle 50 ℃, temperature of separation kettle 40 ℃, pressure of extraction kettle 30 MPa, pressure of separation kettle 0.4 MPa, flow rate of carbon dioxide 20 g/min, extraction time 90 min, extraction yield of essential oil was 4.79%. Compared with simultaneous distillation extraction (SDE), supercritical carbon dioxide required less time and had higher extraction yield by diffusing into the sample particles quickly and dissolving the essential oil components fully without solvent residue. D-limonene (50.96%) and carvone (46.65%) were the main components of the essential oil extracted by supercritical carbon dioxide, and the type and relative content of volatile compounds were both higher than the essential oil obtained by SDE. Conclusion:Compared with SDE, the supercritical carbon dioxide was more suitable for the extraction of Carum carvi L. essential oil.

Abstract:Objective:In order to control the potassium ion content in Carrageenan, this project used alcohol inhibition method instead of potassium ion solution to extract Carrageenan.Methods:The volume fraction of ethanol in the processes of alkali treatment, alkali residual cleaning, and precipitation of carrageenan after filtration during the extraction were optimized for controlling K+concentration.Results:The concentration of ethanol to inhibit the dissolution of Carrageenan was 60% in the process of alkali treatment and cleaning residual alkali, and the ratio of 60% ethanol solution to glue solution was 5∶1 in the process of Carrageenan precipitation. By using this process, the yield of Carrageenan was (28.76±1.38)%, and the Carrageenan of potassium ion was 0.63%, which was significantly lower than that of potassium ion extracted from traditional Carrageenan (16.26%). In addition, the gel strength was significantly lower than that of Carrageenan extracted by traditional methods. And there was no significant difference in viscosity, hardness, elasticity, chewiness, and recovery between the two methods.Conclusion:K+concentration and gel strength of Kappa-carrageenan extracted by ethanol inhibition were significantly lower than traditional technology.

Abstract:Objective:optimizing the extraction process of methylated catechin from Zijuan tea.Methods:Using acid ethanol as extraction solvent, based on three single factor experiments, the extraction time, extraction temperature and liquid-solid ratio were used to investigate the interaction of the above three factors on the extraction rate of methylated catechin from Zijuan tea.Results:The optimum extraction conditions were as follows: extraction time 100 min, extraction temperature 75 ℃, solid-liquid ratio(m Zijuan tea∶VSolvent)1∶74(g/mL); under these conditions, the mass concentration of methylated catechin in the extract could reach 26.7 mg/g, and the relative error with the verification value was 1.48%.Conclusion:HPLC and response surface methods were used to optimize the extraction process of methylated catechins in Zijuan tea. The process is simple and the verification results are reasonable.

Abstract:Objective:This study aimed to analyze the impact of the addition of GMS and the cooling temperature on crystallization behavior of the beef tallow during the production process of beef tallow-hot pot seasoning.Methods: Exploring by measuring the hardness, solid fat content (SFC), color, and isothermal crystallization kinetic parameters of the beef tallow in the beef tallow-hot pot seasoning.Results: When the GMS addition exceeded 1.5%, the hardness of the beef tallow increased related to the amount of GMS, without significant impact on the SFC. Meanwhile, as he cooling temperature decreases, the hardness and SFC of the beef tallow showed an increasing trend. The difference was significant at the temperature range of 0~-15 ℃, and insignificantat-15~-25 ℃; In addition, the fitting results of the isothermal crystallization curve and Avrami equation reveal the significant effects of GMS addition and cooling temperature on the crystallinity property of beef tallow.Conclusion: The optimization of GMS addition and cooling temperature can achieve the adjustment of hardness, color, and cooling time of beef tallow-hot pot seasoning to improve the competitiveness and energy consumption.

Abstract:Objective:To determine the quality changes of the quality of pork ribs in simultaneous combination of steam and microwave cooking.Methods:The physicochemical quality, texture, fatty acids, amino acids, total thiol group, total carbonyl and vitro protein digestibility of pork ribs treated with simultaneous combination of steam and microwave were investigated.Results:The simultaneous combination of steam and microwave could significantly reduce the cooking time compared with the single steaming. And the combined cooking of microwave with 500 W and steam with 1 300 W for 13 min (MS-13) could reduce 48% of the cooking time. Compared with other groups, the pork ribs of MS-13 group had the highest moisture content, protein content and sulfhydryl content, which were higher than those of the individual steamed group for 5.91%,5.85%and 101.60%, respectively, which were higher than the microwave group for 14.55%, 4.90% and 19.78%, respectively. The pork ribs of MS-13 group had the lowest fat content and carbonyl content, which were 91.87% and 45.02% of the individual steamed group, and 95.48% and 67.18% of the individual microwave group. Compared with fresh pork ribs, the relative contents of unsaturated fatty acids of MS-13 group increased significantly.Conclusion:It can be seen that the pork ribs cooked by microwave with 500 W and steam with 1 300 W for 13 min had better sensory and nutritional quality.

Abstract:Objective:This study aimed to obtain the best fermentation time of Yunnan traditional Xinping pickles. Methods:Sensory evaluation and texture measurement of Xinping pickles under different fermentation times were carried out, and the pH value and nitrite content were determined according to the national standard method. Results:As the fermentation progressed, the sensory aspect of Xinping pickles gradually increased in color and texture, and stabilized after 6 days. The aroma and taste scores increased firstly, and then began to decline after 7 days. In terms of texture, the chewiness of the shank started to stabilize from Day 7. The pH value was 4.67 when it reached maturity after 7 days of fermentation, and then dropped and stabilized at around 4.3. The nitrite peak appeared at 20 hr of fermentation, and the nitrite content dropped to 1~3 mg/kg after 2 days. Conclusion:Considering the sensory, texture, pH and nitrite content changes, Xinping pickles that are fermented for about 7 days have the best quality.

Abstract:Objective:This study focuses on realizing the reuse and resource optimization of corncobs.Methods:Using corncob as raw material, using cellulase and hemicellulase to synergistically degrade corncob to prepare reducing sugars. Based on single factor test, response surface methodology was used to determine the mass ratio of cellulase to hemicellulase and double-enzyme process conditions, including addition amount, enzymolysis time, enzymolysis temperature, were optimized.Results:The optimal process parameters for corncob degradation to produce reducing sugars were as follows. The mass ratio of cellulase to hemicellulase was 13∶2, and the amount of double enzyme added was3.25%, hydrolyzed at 50 ℃ for 5.0 h. The reducing sugar content in the corncob enzymatic hydrolysate prepared under the conditions could reach 12.45 mg/mL.Conclusion:The use of cellulase and hemicellulase to synergize the degradation of corncobs to efficiently and directionally prepare reducing sugars can achieve highvalue utilization of corncobs.

Abstract:Objective:This study focuses on optimizing the heat pump drying process of carrot.Methods:On the basis of single factor experiment, Box-Behnken experiment was designed. Color difference, rehydration ratio and β-carotene content were used to study the effects of initial temperature, drying temperature rise and slice thickness on carrot drying quality. The regression equation was established, and the interaction between three independent factors on the response was analyzed. The optimal drying process parameters and the predicted values of carrot heat pump drying were obtained. Finally, the optimal parameters were determined by comparing the experimental results with the predicted values.Results:The optimal process parameters of carrot heat pump drying were as follows: the initial and drying temperature were 54.1 ℃ and 9.25 ℃ respectively, and the slice thickness was 3.8 mm. Under the control of these conditions, the color difference value of carrot was 9.759, the rehydration ratio was 6.196, with the content of β-carotene of 34.378 mg/100 g. The dried product was bright orange red, and the rehydration ratio and the retention of β-carotene were high.Conclusion:Response surface method can determine the best process parameters of carrot heat pump drying, and help to obtain the best quality of carrot dried products.

Abstract:Objective:In order to explore the effect of arrowhead starch on the quality of fresh noodles, arrowhead starch in different proportions were added into wheat core powder to make fresh noodles. Methods:The cooking characteristics, color, sensory evaluation, texture characteristics and GC-MS of fresh noodles were measured. Results:Increasing the amount of arrowhead starch can not only increase the water absorption rate, broken rate and cooking loss rate of noodles as a whole, but also increase the flavor, hardness and elasticity of noodles, and reduced the chewiness, stickiness and taste quality of noodles as well as. When the addition of arrowhead starch was 5%, the sensory score of arrowhead fresh noodles was optimal. The optimized cooking time of the fresh noodles was 4.5 min, which had a 0% noodle breakage rate, 5.28% cooking loss rate and 70.09% water absorption rate. The color difference △E* was 2.31. GC-MS showed that the fresh arrowhead starch noodles were rich in hydrocarbons and alcohols. Conclusion:Adding a proper amount of arrowhead starch could improve the quality of fresh noodle.

Abstract:In this review, the cultivation environment, research and development status, nutritional composition, health effect and application in food and medicine of Changzhi region characteristic export products“Qinzhou Huang”millet were summarized,and its development prospects, development and utilization were prospected.

Abstract:In this paper, walnut oil was reviewed from four aspects: nutritional components, extraction technology, efficacy and compounding. The changes of nutritional components of walnut oil with different extraction technology and compounding methods were discussed. The future research direction was prospected. The constraints of emerging technology and the new compounding method of walnut oil were the focus of walnut oil research in the future.