Abstract:Objective: This study aimed to control the degree of crosslinking and etherification in the preparation process of crosslinked hydroxypropyl starch and improve the product performance. Methods: Waxy corn starch was used as a raw material to prepare the composite modified starch （hydroxypropyl distarch phosphate, HDP） under alkaline conditions, during which process sodium trimetaphosphate （STMP） and propylene oxide （PO） was used as the cross-linker and etherifying agent, respectively. The effects of the addition level of STMP and PO on the properties of the Brabender viscosity behavior, transparency and freeze-thaw stability of waxy corn starch were investigated. Results: Combined with the preliminary laboratory exploration and the optimization of this study, a HDP with improved thermal stability, transparency and freeze-thaw stability and lowered gelatinization temperature was obtained. The preparation conditions of HDP were as follows: in the case that the amount of sodium trimetaphosphate was 0.30 g/100 g and cross-linking reaction time was 45 minutes, and the amount of propylene oxide added was 6 mL/100 g and the etherification time was 90 minutes. Conclusion: Compared to raw waxy corn starch, the cross-linked and etherified starches with decreased gelatinization temperature and improved freeze-thaw stability, thermal stability and gelling properties are observed.

Abstract:Objective: This study aimed to explore the feasibility of preparation of loaded losartan starch nanoparticles by high-speed shear-reverse microemulsion crosslinking. Methods: Using losartan as model drug and sodium trimetaphosphate as crosslinking agent, the effects of starch solution concentration, sodium trimetaphosphate addition amount, crosslinking time and shear rate on particle size and yield of starch nanoparticles were investigated. Optical micrography, infrared spectrometer and X-ray diffraction were used to characterize losartan loaded starch nanoparticles. Results: The optimal preparation process of nanoparticles was 15% starch solution concentration, 25% sodium trimetaphosphate, 3 h crosslinking time, 5 000 r/min shear rate. Under the control of these conditions, the minimum size of nanoparticles was 755.2 nm, and the yield reached 69.5%. Optical micrography showed that the nanoparticles were round, full and spherical. FTIR showed that losartan was successfully loaded into starch nanoparticles. XRD showed that the nanoparticles exist in amorphous structure. Conclusion: Small particle size drug-carrying starch nanoparticles can be prepared by high-speed shear coupled reversed-phase fine emulsion crosslinking method.

Abstract:Objective: This study aimed to enrich the functional lactic acid bacteria resource bank and to search for excellent starting strains of lactic acid bacteria with the antagonistic ability of Vibrio parahaemolyticus. Methods: Lactobacillus strains with broad-spectrum bacteriostatic potential were screened by Oxford cup bacteriostatic test, and their biological characteristics were discussed by growth and metabolic performance, gastrointestinal fluid tolerance, salt tolerance, antibiotic sensitivity and bacteriostatic spectrum. Results: Six strains of lactic acid bacteria were screened by using V. parahaemolyticus as indicator bacteria. They were classified into L. paracasei, L. fermentus and L. plantarum by morphological, physiological and biochemical identification and molecular biological identification. Among them, the bacteriostatic activity of L. paracasei A1 was the best, the total number of colonies within 24 hours exceeded 1×10⁹ CFU/mL, and the pH value of fermentation broth was stable at about 4.1. After artificial simulated gastric juice treatment for 2 h, the survival rate was 54.61%. After artificial simulated intestinal juice treatment for 8 h, the survival rate still reached 45.46%. After 10% NaCl stress treatment for 24 h, the total number of viable bacteria was ＞ 1×10⁵ CFU/mL. Moreover, the crude bacteriocin extract of L. paracasei A1 showed good antibacterial activity against 13 pathogenic bacteria, had broad-spectrum antibacterial potential, and no resistance to 8 common antibiotics was found. Conclusion: L. paracasei A1, which can inhibit V. parahaemolyticus and has excellent biological characteristics, was obtained.

Abstract:Objective: To broaden the selection of strains for fermenting fresh rice noodle and develop the application of different strains in fresh rice noodle （FRN）. Methods: With gelatinization, texture, cooking stretching, electronic nose, electronic tongue and sensory evaluation as evaluation indexes, and L. fermentum FR-21, A. orientalis AO-21, L. plantarum YI-Y2013 and blank samples as influencing factors, the eating quality of FRN fermented by different strains was analyzed. Results: L. fermentum FR-21 fermentation improved the gelatinization indexes of indica rice flour, such as valley viscosity, disintegration value, final viscosity and retrogradation value, and reduced the texture viscosity of FRN, and improved its sensory hardness and typical fermented flavor （smell 4.0 points）. The FRN fermented by A. orientalis AO-21 had the lowest cooking loss （1.63%）, high texture hardness and chewability, relatively strong aftertaste, and obvious acidic odor （smell 3.7 points）. L. plantarum YI-Y2013 was similar to L. fermentum FR-21 in gelatinization index and textural viscosity, such as valley viscosity, disintegration value, final viscosity and retrogradation value （P＜0.05）, while the FRN fermented by L. plantarum YI-Y2013 had the highest extensibility （48.83±1.00）, and the smell was fragrant and pure （smell 4.6 points）. Conclusion: The controlled fermentation of three different strains can make FRN present different taste qualities, and rice noodles with different flavor qualities can be produced by using their fermentation characteristics.

Abstract:Objective: This study aimed to investigate the effect of adding oat flour on the characteristics of potato-oat compound dough and determine the appropriate ratio of oat flour and potato. Methods: Five different ratios of oat flour (15%, 20%, 25%, 30% and 35%) were selected and the color difference, microstructure, textural properties, rheological properties and pasting properties of the oat-potato composite dough were measured and sensory evaluation was carried out. Results: With the increase of oat flour, the color of compound dough gradually changed to red and dark. The internal microstructure of the composite dough was getting closer and closer, and hardness increased gradually; in the dynamic frequency scanning process, the elastic modulus and viscosity modulus of the compound dough with different addition amounts first increased, then decreased and then increased, and the loss factor first increased and then decreased. The initial gelatinization temperature, peak gelatinization temperature and end gelatinization temperature of compound dough decreased first and then increased. The sensory evaluation showed that the overall score of oat flour was higher than that of composite dough with other added amounts in the range of 20% ~ 25%, and it was more acceptable to consumers. Conclusion: The appropriate amount of oat flour to be added was between 20% and 25%.

Abstract:Objective： To establish a rapid qualitative and quantitative method for the adulteration of Camellia seed oil. Methods： The electronic nose technology combined with chemometrics was used to screen the difference variables based on one-way ANOVA. The qualitative model for identification of adulteration types of camellia seed oil was established through principal component analysis (PCA) and discriminant analysis (DA). A quantitative model for identifying the types and degrees of camellia seed oil adulteration was established using orthogonal partial least squares (OPLS). Results： The R² of the model was over 0.98, the RMSEE was lower than 0.005, and the RMSECV was lower than 0.01, which had the high performance indicators. Through external verification, the qualitative identification rate of DA model for camellia seed oil samples of different adulteration types was as high as 100%, and OPLS model had good accuracy. Conclusion： The electronic nose technology combined with chemometrics could realize the rapid and nondestructive identification of camellia seed oil adulteration.

Abstract:Objective: To realize the rapid traceability detection of Astragalus membranaceus from different origins. Methods: This study proposed a rapid detection method for the origin of Astragalus membranaceus based on the improved MobileNetv3 network based on the combination of electronic tongue and electronic eye. The electronic tongue and electronic eye were used to collect the one-dimensional fingerprint and two-dimensional appearance image information of different samples of Astragalus membranaceus. The Gramian Angular Field (GAF) was used to convert the one-dimensional electronic tongue signal into two-dimensional image information, retain the time series related features in the electronic tongue signal, and then fused them with the image information collected by the electronic eye. Finally, the MobileNetv3 model improved based on Pyramid Split Attention (PSA) was adopted to realize the classification and recognition of Astragalus samples from different habitats. Results: The experimental results showed that the method in this paper had higher recognition accuracy than using electronic tongue or electronic eye alone. The accuracy, precision, rrecall and F₁-score of the test set were 98.8%, 98.8%, 98.8% and 0.99, respectively. The classification accuracy of the improved MobileNetv3 network was 8% higher than that of the original model, and the parameter quantity was only about 1/5 of the original parameter quantity. Conclusion: The improved MobileNetv3 network can effectively reduce the calculation of parameters and improve the recognition accuracy of Astragalus membranaceus from different origins.

Abstract:Objective: This study aimed to establish a method for the simultaneous determination of 80 veterinary drugs including quinolones, sulfonamides, receptor agonists, glucocorticoids, macrolides, tetracyclines, antiviral drugs in chicken by QuEChERS - ultra high performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS）. Methods: The samples were extracted by 1% formic acid acetonitrile aqueous solution, purified by QuEChERS multi-veterinary drug residue purification column, detected by ultra-high performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS） multi-reaction monitoring mode, and quantified by matrix standard curve external standard method. Results: The results showed that 80 kinds of veterinary drugs were highly responsive under specific mass spectrometry conditions, and the samples were sensitive to detection under the conditions of mass spectrometry without interference of foreign peaks. The correlation coefficient of 80 drugs were greater than 0.99 in the range of 5.0～100 μg/L, with good linearity. The detection limit of 80 veterinary drugs were 1.0 μg/kg. The average recovery of spiked concentration of 2.0, 5.0, 10.0 μg/kg in the sample was 62.2%～106.8%; RSD was 2.07%～10.85%. Conclusion: The recovery rate of 80 drugs in the samples conformed to the standard requirements of GB/T 27404—2008 Code for Laboratory Quality Control - Physical and Chemical Testing of Food. The method was suitable for the screening and determination of 80 veterinary drug residues in chicken.

Abstract:Objective: This study aimed to establish a method by using QuEChERS-gas chromatography tandem mass spectrometry (GC-MS/MS), to determine six pesticide residues in tea, including: hydroprene, kinoprene, genite, fluronitrofen, cycloprate, and chlornitrofen. Methods: The samples were pretreated by QuEChERS method. They were separated by gas chromatographic, detected by multiple reaction monitoring (MRM) mode and quantified by the external method. Results: All the pesticide residues showed good linearity with correlation coefficients above 0.999 when the concentration falls in the range 0.025~2.000 mg/kg, and the limits of quantitation were in the range of 0.000 6 ~0.007 2 mg/kg. In the recovery experiment of 0.002 5 mg/kg, 0.05 mg/kg, and 0.5 mg/kg at three concentrations, the average recoveries were 84.3%5~116.3%, and the relative standard deviations (RSDs) were 1.07%~6.05%. Conclusion: The method is rapid, simple, and accurate, which is suitable for the detection of these six pesticide residues in tea.

Abstract:Objective: The uncertainty of determination of three pyrethroid pesticides （cypermethrin, fenvalerate and deltamethrin） in fresh tea leaves by gas chromatography was evaluated. Methods: A mathematical model was established according to the determination process of the experiment, and the uncertainties caused by various factors in the model were identified. The sources are mainly the following 7 aspects: repeated determination of samples, fitness of standard curve, recovery rate, standard solution preparation, sample weighing and pretreatment, and the measurement of instrument. Results: At the spiking level of 0.10 mg/kg, the expanded uncertainty of measured values of cypermethrin, fenvalerate, and deltamethrin were 0.011, 0.011 and 0.012 mg/kg, respectively. The detection results of three pesticides in fresh tea leaves in 95% confidence interval could be expressed as cypermethrin: （0.093±0.011） mg/kg, fenvalerate: （0.094±0.011） mg/kg, deltamethrin: （0.098±0.012） mg/kg （k=2）. Conclusion: The uncertainties of the method were mainly introduced by standard solution preparation, calibration curve fitting and recovery rate, indicating that these aspects should be controlled strictly in the following sample analysis.

Abstract:Objective: Establish a high throughput method for the determination of 57 organic pollutants in edible vegetable oil. Methods: The target compounds were extracted by acetonitrile-hexane solution and purified by disperse solid phase extraction and solid phase extraction, after that the contents of 16 polycyclic aromatic hydrocarbons, 17 phthalates, 8 organochlorines and 16 polychlorinated biphenyls in edible oil were detected by gas chromatography triple quadrupole mass spectrometry. Results: All target components had an excellent linearity within the linear range of 0.001～0.1 μg/mL （r²＞0.998）, and the limits of detection was between 0.16～2.0 μg/kg, meanwhile the average recovery rate of matrix addition was between 71.0%～119.5%, and the relative standard deviation was below 12.6% （n=6）. Furthermore, the method was used to analyze 24 baches of edible oils, and 25 types of target substances were founded. Conclusion: This method is high efficiency, accuracy, high sensitivity, which has great significance for the monitoring of persistent organic pollutants and phthalates in edible oil.

Abstract:Objective: The molecular biological test has the advantage of fast and sensitive, which can effectively make up for the defects of the traditional microbial test method. Methods: According to the conserved sequences of the V3~V4 region of the virulence gene pcrL and the universal gene 16S rRNA of Pseudomonas aeruginosa in GB 8538—2022, primers and probes were designed and synthesized, and a real-time fluorescent PCR kit was established in this study. Results: The results showed that the common standard reserve strain 16S rRNA was amplified, and the virulence gene pcrL was only effective for nucleic acid detection of Pseudomonas aeruginosa standard reserve strain, and obvious "S" type amplification curve could be observed, while no amplification curve was found for common food-borne pathogens in this study. Gene pcrL still has amplification curve, when the concentration of bacterial solution was less than 10 CFU/mL, the detection range was 10~10⁷ CFU/mL, and the detection limit was 10 CFU/mL. The Ct mean value of virulence gene pcrL under different bacterial solution concentrations ranged from 18.0 to 38.6. The results showed that this method was highly sensitive to the detection of the virulence factor pcrL carried by Pseudomonas aeruginosa. In the past three years, the unqualified Pseudomonas aeruginosa samples in 14 counties and cities of Hunan Province were further detected, and the coincidence rate reached 100%. Conclusion: This method is highly sensitive to detect the virulence factor pcrL carried by Pseudomonas aeruginosa. It has the advantages of simple operation, strong specificity, high sensitivity and good practicability.

Abstract:Objective: A novel electrochemical sensor with high sensitivity was developed for the quantitative analysis of rutin in tartary buckwheat. Methods: A layer of titanium dioxide was loaded on the surface of ferric oxide nano materials (Fe₃O₄) to prepare core-shell Fe₃O₄@titanium dioxide (Fe₃O₄@TiO₂) nano composites, and nano gold (Au) was loaded on its surface for preparing a new type of Fe₃O₄@TiO₂@Au nanocomposites. Then an electrochemical sensor was constructed for quantitative analysis of rutin. The optimal working conditions of the sensor were determined by electrochemical characterizing of nano materials, rutin and optimizing, buffer pH, enrichment time, enrichment potential and other conditions. Results: Fe₃O₄@TiO₂@Au had good adsorption and conductivity, which could effectively improve the sensitivity of the sensor. Rutin concentration and its corresponding oxidation peak current show linear relationship in the concentration range of 0.02～20 μmol/L and 20～200 μmol/L, respectively. The detection limit (S/N=3) was 0.006 4 μmol/L, and the linear range was wide and detection limit was low. It is obviously better than other electrochemical sensors, and the sensor prepared had good repeatability, stability and good anti-interference ability to common co-existing objects. Conclusion: The prepared sensor had the advantages of simple operation, low cost and the potential of recycling of nanocomposites, which provides a more effective method for rapid quantitative analysis of rutin.

Abstract:At present, China has preliminarily established a food safety supervision system for imports and exports, with the current 21 year Food Safety Law as the basic law and the inspection and quarantine department as the main regulatory body. However, there are still problems such as low food safety standards, low management and technical level of regulatory departments, and lack of necessary coordination with major trading partners. In this regard, we can optimize and construct the legal supervision of China's import and export food safety from the dimensions of building scientific food safety standards that are in line with international standards, strengthening the management and technical capacity building of regulatory authorities, and establishing a food safety notification and coordination mechanism with major trading partners.

Abstract:Objective: In view of the problems of large size and low heating uniformity of the existing cooking machine, a miniaturized drum-type automatic cooking machine with electromagnetic heating was designed to reduce the equipment volume and improve the cooking effect. Methods: The modular design method oriented to function and structure was adopted to design each module mechanism of the frying machine. Then, based on Biot-Savart law, the relationship between the magnetic field generated by the coil in space and the current and distance is obtained, and the distribution curves of magnetic field intensity and temperature on the surface of the cooker under three coil arrangements are obtained by Ansys-Maxwell joint simulation. Secondly, the modal analysis of the sliding rail mechanism is carried out by Ansys software, and the frequency band of improper deformation of the mechanism is obtained. Finally, a prototype was developed and compared with three cooking methods to verify the cooking effect of the proto type. Results: Compared with the existing cooking machine, the heating uniformity was greatly improved, and the structural design and actual cooking effect met the use requirements. Conclusion: The research and design of automatic cooking machine has high feasibility and practicability.

Abstract:Objective: To improve the mixing efficiency and working performance of the new twin-screw extruder. Methods: A new twin-screw extruder with embedded planetary gear train and kneading block was designed. A three-dimensional model was established by SolidWorks, and the flow field analysis of the flow channel was performed by ANSYS/CFS finite element analysis software based on the finite volume method. The Macroscopic pressure diagram, velocity vector diagram, velocity flow diagram were gotten, which was compared with the traditional twin-screw extruder three-dimensional flow field. Results: Under the gradual action of the planetary gear train and the kneading block, the mixing performance and working efficiency of the stepwise acceleration twin screw extruder were significantly better than those of the traditional twin screw. By calculation, the stepwise accelerated twin screw was 20% ~ 25% higher than the traditional twin screw. Conclusion: In the process of continuous acceleration, the gradual acceleration twin screw makes the residence time of the material in the barrel shorter o increase production and reduce energy consumption, and the addition of kneading block makes the material get better shearing.

Abstract:Objective: This study aimed to induce the machine vision technology into the appearance detection of Pleurotus eryngii. Methods: A bilateral filter was proposed to replace Gaussian filter as image smoothing filter, and Ostu maximum inter-class variance method was proposed to replace the improved Canny operator, based on fixed double threshold segmentation, and used as edge detection algorithm. HALCON operator and color space conversion were used to extract the length, diameter, curvature, evenness, color and cap defects of P. erynii, and the development and design of visual software function modules were completed, under the VS 2017 development environment with HALCON 18.05 and C#. Results: 200 pieces of P. eryngii were randomly obtained to test the accuracy of the algorithm and the performance of the visual software. The diameter grading accuracy of the Pleurotus eryngii was 83%, and the remaining characteristic elements could reach more than 95%, with the overall classification accuracy of all specifications more than 90%. Conclusion: The classification of appearance quality of P. eryngii can be completed through the improvement of algorithm and the design of visual software.

Abstract:Objective: In order to solve the problems of low efficiency and high false detection rate of current fruit classification detection methods, a fruit classification system based on machine vision was designed with apples as the sorting object. Methods: The apple image collected in real time was preprocessed, the improved Canny edge detection algorithm was used to extract the edge, and the radius of the apple cross-section was obtained by fitting the edge coordinates with the minimum peripheral circle method. The acquired RGB image was converted to HSI image, and the proportion of red region is calculated according to the range of H component to determine the color of apple. Count the number of pixels in the area, and calculate the area and circumference of the apple respectively to calculate the roundness of the apple. Combined with three characteristic values of diameter length, color and roundness, apple was graded comprehensively. Results: Through the test of 50 apple samples, the error range of fruit diameter measured by the fruit grading system and manual sorting was within ±1.5 mm, the color characteristics of the samples were consistent with the actual appearance of the apple, and the result size of the roundness value was consistent with the actual shape. Conclusion: The system can meet the demand of apple classification in actual production and help to realize the accurate identification of apple grade.

Abstract:Objective： This study aimed to provide a basis for the post-harvest storage and preservation of fresh shoots from bamboo (Chimonobambusa quadrangularis). Methods: Fresh bamboo shoots were fumigated with 500 μL/L anhydrous ethanol and 0.1 mmol/L MeJA, and distilled water was used as blank control (CK) to determine the storage period, i. e. temperature (1.0±0.3) ℃ and relative humidity (90±5)%. The respiratory intensity, hardness, browning index, soluble protein, and activity of PAL, POD, PPO and APX were detected. The quality differences of fresh bamboo shoots during storage were analyzed using principal component analysis. Results: Combined fumigation treatment can reduce the increase of hardness and browning index of fresh bamboo shoots during storage, maintain the contents of total flavonoids and soluble protein, induce the changes of APX, POD, PAL and PPO enzyme activities, and delay lignification and browning. As stored for 60 days, the principal component analysis of combined fumigation was higher than that of other treatments. Conclusion: Compound fumigation can better maintain the quality of bamboo shoots during storage.

Abstract:Objective: This study aimed to compare the effects of different sterilization on the quality of fermented jujube juice. Methods: The effects of cold plasma sterilization (CPS) and pulsed strong light sterilization (PLS) on the quality of jujube juice before and after fermentation were studied, with high pressure sterilization (SA) jujube juice as the control. Results: The contents of total sugar, reducing sugar and soluble solid in jujube juice before and after fermentation by CPS treatment were significantly higher than those of the other two sterilization methods, and the contents of total sugar, reducing sugar and soluble solid in jujube juice after fermentation were 1.7 mg/L, 1.64 mg/L and 12.4%, respectively. With SA treatment, the total phenol content of jujube juice before and after fermentation was the lowest, and the total phenol content of jujube juice after fermentation was only 2.19 mg/L. The color of jujube juice treated by PLS changed minimally before and after fermentation. The viable count of Lactobacillus plantarum in jujube juice treated by CPS, PLS and SA were more than 6.48 lg（CFU/mL） after 48 h fermentation by L. plantarum, and the viable count of L. plantarum in jujube juice was the highest 6.63 lg(CFU/mL) after PLS treatment. Conclusion: Non-thermal sterilization (especially PLS) has little effect on the quality of fermented jujube juice and could be applied in the processing of fermented jujube juice.

Abstract:Objective: The effects of freezing method and storage temperature on the quality of large yellow croaker during storage were investigated. Methods: Fresh large yellow croaker fillets were frozen with dry ice and air freezing (-40 ℃) to the central temperature of -18 ℃, and then stored at -40 ℃ and -18 ℃, respectively. Physical and chemical indexes such as freezing curve, ice crystal morphology, pH value, volatile base nitrogen, K value, Ca²⁺-ATPase activity, total sulfhydryl group, carbonyl group, protein degradation and texture characteristics of large yellow croaks were determined after freezing and during freezing storage. Results: The time of dry ice freezing through the maximum ice crystal formation zone was 40 min, which is 1/6 of that of air freezing at -40 ℃. The initial ice crystal cross-section area and equivalent diameter of dry ice frozen fish samples were (96.12±1.61) μm² and (11.06±1.43) μm, respectively, which is significantly lower than that of air frozen fish samples. Conclusion: The effect of freezing temperature on fish myofibrillator protein was greater than that of freezing temperature, and a lower freezing temperature can result in a lower degradation degree of fish myofibrillator protein. Storage at -40 ℃ after dry ice freezing is beneficial to maintain freshness and quality stability of large yellow croaker.

Abstract:Objective: To improve the storage safety of Xinjiang fresh walnut. Methods: Xinjiang "Xin 2" thin-skinned walnut was used as material, sterile water was inoculated as a control group, and Aspergillus flavus was inoculated as an experimental group. The Aspergillus flavus isolated and purified from naturally moldy walnut was artificially inoculated into Xinjiang thin-skinned fresh walnut with different water content （10%, 15%, 20%, 25%, 30%） to investigate the growth and toxicity of Aspergillus flavus. Results: The water content of walnut which was suitable for the growth of Aspergillus flavus and the secretion of Aflatoxin M₁ was 15%. With the increase of walnut water content, the growth of Aspergillus flavus increased first and then decreased, but the growth of each water content was different, and the growth of Aspergillus flavus was proportional to the content of Aflatoxin M₁. Conclusion: The water content of raw materials is closely related to the growth of Aspergillus flavus and the content of Aflatoxin M₁ produced.

Abstract:Objective: This study aimed to investigated the effect of ice-temperature vacuum drying on the powder quality of selenium-rich Rugao black pakchoi. Methods: After pretreatment, the fresh black pakchoi was dried to the moisture content of (5.0±0.5) %, and the physical and chemical indexes were investigated, comparing to the control groups of hot-air drying, vacuum drying and freeze-vacuum drying. Results: The vitamin C content of vacuum drying at ice temperature was 554.60 mg/100 g, and the retention rate reached 83.96%, which was 43.11%, 33.57% and 1.61% higher than that of hot-air drying, vacuum drying and freeze-vacuum drying, respectively. Glutathione peroxidase had little activity loss and the best purity maintenance. The retention rates of total phenols and total flavonoids were 59.69% and 60.58%, respectively, which were better than the other three groups. In terms of microstructure, the powder of ice-temperature vacuum drying group was well-distributed, with a smooth and flat surface and less debris. Compared with the other three groups, the ice-temperature vacuum drying group could maintain the original dark green color, and the rehydration and solubility were improved. Conclusion: The ice-temperature vacuum drying process can minimally affect the Rugao black pakchoi powder, and the nutritional quality of this powder is the highest.

Abstract:Objective: To solve the problems of low accuracy and poor efficiency in existing apple defect detection methods. Methods: Based on a fruit image acquisition system, an improved convolutional neural network was proposed for detecting surface defects in apples. Deep separable convolution was Introduced to replace the original network standard convolution, to improve the speed of feature extraction. The Leaky ReLU activation function was introduced to replace the ReLU activation function to improve the calculation efficiency and accuracy. Global average pooling was introduced to replace the fully connected layer, to reduce the computational complexity of the network model. After each layer of convolution, a batch normalization layer was added, and its superiority was verified through comparative analysis between experiments and conventional methods. Results: Compared with conventional methods, the proposed method had higher detection accuracy and speed in apple defect detection, and had fewer model parameters, with an accuracy rate of 99.60%, a detection speed of 526 FPS, and a model parameter quantity of 389 072. Conclusion: This apple defect detection method can effectively reduce model parameters and detection time, with high accuracy and speed.

Abstract:Objective: This study aimed to investigate the antidepressant effect of hydroxyl safflower yellow A on rats induced by lipopolysaccharide. Methods: The depression model of rats was established by intraperitoneal injection of LPS. The normal control group, the model group, the positive control group and the hydroxyl safflower yellow A groups with different doses were set up, and the depression like behavior of rats was evaluated. The contents of TNF-α, IL-1β, IL-6 and BDNF, 5-HT in serum of rats were determined, and the histopathological changes of hippocampus were observed. The protein expression of TLR/NLR signaling pathway was detected. Results: Compared with the depression model group, the horizontal movement, vertical movement and sucrose preference of rats in each dose group of hydroxyl safflower yellow A group were increased, while tail suspension and swimming immobility time were decreased (P＜0.01). the serum levels of BDNF and 5-HT were increased while the levels of TNF-α, IL-1β and IL-6 levels were decreased (P＜0.01). The protein expression levels of TLR2, NLRP1, NLRP3, ASC, TLR4 and Caspase-1 in hippocampus tissue were decreased (P＜0.01). Conclusion: Hydroxyl safflower yellow A can improve the depression-like behavior of rats induced by LPS, and the mechanism may be related to the inhibition of TLR/NLR signaling pathway.

Abstract:Objective: This study aimed to explore the improvement effect of sesamol on skin lesions caused by psoriasis. Methods: The psoriasis model was constructed by using 5% imiquimod cream applied to the backs of mice for seven consecutive days, with sesamol intervention used from one week before to the end of modelling to explore the protective effect of sesamol on the skin. Then, observed and measured skin thickness, PASI score, spleen index, pathological tissue sections, cytokines (IL-17, IL-23, TNF-α and other inflammatory factors and chemokines like CXCL1 and CCL20), and inflammatory factors (IL-17, TNF-α) in plasma of mice in each group, to analyze the effect of sesamol on the inhibition of psoriasis-like inflammation in mice. Results: The results showed that the skin of the model group of mice showed typical lesion manifestations and pathological features of psoriasis on the back. The application of 3% sesamol solution inhibted skin lesions and epidermal hyperplasia, decreased splenic index, and significantly reduced the expression of cytokines in skin tissues and plasma. Conclusion: Sesamol can significantly ihhibit the skin lesions, reduce the pathological features, and down-regulate the expression of inflammation of mice in psoriasis model.

Abstract:Objective： This study aimed to develop relevant health products with ginseng and semen ziziphi spinosae as raw materials. Methods: HPLC and UV spectrophotometer were used to study the chemical components of different compatibility ratios of ginseng and semen ziziphi spinosae. The antioxidant activity in vitro of ginseng and semen ziziphi spinosae with different compatibility ratios was analyzed by DPPH free radical, ABTS⁺free radical, hydroxyl free radical and superoxide anion free radical scavenging rate. Moreover, the grey relational degree method was used, and entropy weight method was used as the discrimination coefficient for statistical analysis, combined with the characteristics of comprehensive evaluation to optimize the compatibility ratio. Results: The correlation analysis showed that the antioxidant activity of ginseng-semen ziziphi spinosae and the content of total phenolic acid, Jujuboside A and spinosin were significantly correlated; and the chemical content determination results showed that the total phenolic acid, Jujuboside A and spinosin content of ginseng- semen ziziphi spinosae (1∶1) were higher than the other ratio. The results showed that its antioxidant activity was stronger than other ratios. Furthermore, the pharmacodynamic bases of its antioxidant activity were total phenolic acid, Jujuboside A, and spinosin. Conclusion: The optimal ratio of antioxidant activity of ginseng and semen ziziphi spinosae is m _ginseng∶m_{semen ziziphi spinosae} at 1∶1.

Abstract:Objective: This study aimed to develop a kind of fermented hypoallergenic peanut milk with lactic acid bacteria. Methods: The crude protein content and Ara h 1 concentration in different peanut varieties were determined by the kit, and the peanut varieties with the lowest Ara h 1 content were selected to make fermented milk. Response surface method was used to optimize the preparation process of fermented peanut milk with the maximum reduction of sensitizing protein Ara h 1 content with different inoculation amount, inoculation species, fermentation time and sugar addition amount as factors. The compound fermented peanut milk with probiotics was prepared, and the taste, histological state and flavor of the product were evaluated. Results: When inoculated with 4% bacteria, inoculated with Streptococcus thermophilus and Lactobacillus bulgaricus, fermented for 4 h, and added with 6% sugar, the main allergen Ara h 1 in fermented peanut milk was reduced by 70% to 48 μg/g, and the average score of sensory evaluation was 80 points. Conclusion: Through process optimization, a compound probiotic fermented peanut product with low content of sensitizing protein Ara h 1, good curd effect and pleasant taste was obtained.

Abstract:Objective: To promote the intensive processing of Antarctic Krill and enrich the types of minced shrimp products. Methods: Using Krill meat and prawn meat as main raw materials, waxy corn acetylated distarch adipate, egg white powder, soy protein isolate, glutamine transaminase and other adjuvants were added, and the optimal preparation ratio of shrimp balls was obtained through single factor test and response surface test. Results: The optimal preparation ratio of shrimp balls was 6.00% waxy corn acetylated distarch adipate, 5.00% egg white powder, 5.00% soy protein isolate, 0.50% glutamine transaminase and 0.20% konjac gum. Conclusion: The two-stage heating method is used to prepare compound shrimp gel. By adding exogenous additives, the texture properties of compound shrimp gel can be improved and the nutritional value can be guaranteed.

Abstract:Objective: This study aimed to optimize the wet processing of coffee. Methods: The effects of pectinase concentration, temperature and drying method on the contents of flavor precursors and flavor substances in coffee beans were investigated. The quality ranking was obtained by grey correlation analysis and the volatile substances were analyzed. Results: There were significant differences in the contents of protein, crude fat, caffeic acid, caffeine, chlorogenic acid and volatile compounds among different pectinase concentration, temperature, sun drying and heat pump drying. Grey correlation analysis showed that the quality ranking of coffee in the 2% pectinase + 27 ℃+ sun-drying treatment group was the first. The protein content in green coffee beans was 14.04%, the crude fat content was 9.05%, the caffeic acid content in roasted coffee beans was 1.05 mg/g, the caffeine content was 1.41%, and the chlorogenic acid content was 13.89 mg/g. The relative contents of the main volatile substances esters and acids were 40.87 μg/g and 7.62 μg/g, respectively. Conclusion: The comprehensive quality of coffee obtained by 2% pectinase + 27 ℃ + sun-drying was the best.

Abstract:Objective: In order to develop and enrich fruit wine categories and diversify sensory levels, plum and peppermint were chosen out as the main materials for fermenting a compound fruit wine. Methods: Single factor test and response surface test were used to analyze the effects of mint addition amount, initial sugar degree, initial pH value and fermentation temperature on the alcohol and quality of plum peppermint wine. The fermentation process was optimized, and its sensory was analyzed. Moreover, the sensory, physical and chemical indexes and volatile components were detected. Results: The optimum fermentation conditions were as follows: peppermint content 18%, initial sugar concentration 24%, initial pH 3.9, fermented at 21 ℃. Under the control of these conditions, the alcohol content, sensory score, total sugar, total acid and dry extract content was 10.8%, 84, 3.6 g/L, 5.15 g/L and 24.6 g/L, respectively. A total of 16 kinds of flavor components were detected based on SPME-GC-MS, accounting for 81.48% of the total volatile components. The main aromatic compounds were (+) -dihydrocarvone, which had cool aroma and the flavor of orchids. Conclusion: The plum peppermint wine produced by the optimization process meets the standard requirements of fruit wine.

Abstract:Probiotic fermented milk is an important carrier of probiotics. It enhances the nutritional and health properties of fermented milk by improving the balance of host intestinal microflora and promoting the metabolism of beneficial ingredients. This review expounds the auxiliary effects of probiotics fermented milk in improving intestinal function, regulating body immunity, assisting in treating metabolic diseases and improving mental system diseases, etc., in order to provide theoretical support for expanding the application of probiotics fermented milk.

Abstract:Agricultural products usually contain a large number of spoilage bacteria and endogenous enzymes, which can adversely affect the quality of agricultural products. Radio frequency is a kind of dielectric heating technology, which has fast heating speed and high efficiency, can effectively inactivate microorganisms and endogenous enzymes in agricultural products and has little influence on the quality of agricultural products， such as color, texture and nutritional composition, etc. This review summarized the mechanism of action of radiofrequency sterilization blunt enzyme technology and its application in agricultural products processing in recent years, and the shortcomings and solutions of radiofrequency sterilization blunt enzyme technology was pointed out. Moreover, the future application of radiofrequency sterilization blunt enzyme technology in agricultural products and food was also prospected.

Abstract:Theabrownin, a kind of water-soluble, non-dialysable, highly polymerised brown substance, mainly composed of polyphenol, polysaccharide, protein and nucleic acid, which is closely related to the color and functional activity of fermented tea. Due to the complexity of the formation mechanism, its chemical structure is still unclear. In this review, the structural characteristics, formation mechanism, extraction and detection methods, and functional activity of theophylcin were discussed, and the future research direction was also prospected.

Abstract:Gas chromatography-mass spectrometry combines the advantages of efficient and rapid gas chromatography and accurate identification by mass spectrometry. Gas chromatography-mass spectrometry has been widely used in the separation and analysis of volatile components in food recently. This paper reviewed the application progress of GC in food analysis, introduces the separation mechanism of GC, the types of GC columns and the classification of detectors. The application progress of GC-MS in food analysis was reviewed, and the separation process of gas chromatography, the classification of chromatographic columns and the classification of detectors were introduced. Moreover, the applications of gas chromatography-mass spectrometry in food nutrition, food safety and food traceability were discussed in detail with specific examples.