Abstract:The 7 strains with antimicrobial activity were screened as samples and verification by PCR amplification has antimicrobial peptide genes of PlnF, PlnE, PlnN, PlnJ, and PlnK. Then designed a primer to introduce Nco I and Xho I sites into both ends of the antibacterial peptide genes with the treated of pET28a plasmid to obtain recombinant plasmid using T4 ligase, and the pET28a-peptide was transformed into E.coli BL21(DE3). The experiment results showed that the inhibition zone of the pET28a-peptide was the PlnF, after 0.5 mmol/L IPTG inducted for 6 h after the OD₆₀₀=0.6 of the E.coli LB. The cell in the 400 W, ultrasonic for 4 s, with intermittent 5 s for crushing, and then with 8 mol/L urea denaturation and renaturation with Ni purified, the PlnF purified protein has the antibacteria effects to the Staphylococcus aureus with (13.43±0.21) mm compare with the control group. Further by Tricine-SDS-PAGE electrophor-esis and nanoLC ESI/MS/MS verification, the homology of the target protein and PlnF antimicrobial peptide with 97.6%.

Abstract:This review clarified the microbial origin and properties of thermophilic α-amylase, and analyzed eight factors affecting their thermostability. The strategies to improve the thermostability of thermophilic α-amylase were proposed, which provided a reference for improving the thermostability technology of thermophilic α-amylase.

Abstract:In order to improve the bioavailability of zein, which was modified by using the microbial transglutaminase and chitosan. Effects of the enzymatic glycosylation modification on the partial structural and rheological properties of zein were studied. Compared to original zein, the free sulfhydryl groups of the glycosylated zein decreased by 32.37 μmoL/g, the denaturation temperature and the denaturation enthalpy of the glycosylated zein increased by 11 ℃ and 72.3 J/g, respectively. These results suggest that thermal stability of the zein was increased by enzymatic glycosylation reaction.At shearing rate ranging from 1 to 100 s^-1, the dispersions of zein and cross-linked as well as glycosylated zein exhibited shear thinning behaviour, and apparent viscosity of three samples was significantly increased by the enzymatic glycosylation. Meanwhile, the elasticity modulus(G′) of the glycosylated zein and cross-linked one were higher than viscous modulus(G″), and their flow behavior presented as a solid-like character at frequencies of 0.1～10 Hz.

Abstract:In order to study the volatile flavor of soymilk, a soymilk simulation system with soybean oil body as substrate was constructed, The effects of different pH on the components, particle size and flavor of soybean oil body extracted from soybean milk were studied in the oil body extraction process. The results showed that when the extraction pH increased from 7 to 11, the content of oil body protein decreased by 38.40%, the neutral fat content increased by 7.26%, and the phospholipid content decreased by 49.31%. The oil particle size decreased gradually by 89.2 nm and tended to be stable. Volatile flavor substances were also gradually reduced from 129.80 μg/L to 52.17 μg/L. When the pH > 9, the effect of lipoxygenase in extracted oil body was negligible. According to the comparison above, the purity and stability of oil body extracted under the condition of pH 10 were better, and the flavor substances contained in the oil body were also less. It can be seen that the oil body extracted at pH 10 is the most suitable substrate component of soybean milk simulation system.

Abstract:The effects of peony extracts and lactobacillus fermentation broth as nitrite substitute were investigated on color, texture characteristics, lipid-oxidation, microbiological properties and flavor of low-temperature emulsion sausages. The results showed that 0.3% peony extracts and 3% lactobacillus fermentation broth could replace two-thirds of dosage of sodium nitrite in low-temperature emulsion sausages, and its redness value (a^*) and the degree of fat oxidation were similar to the effect of sausage with 150 mg/kg sodium nitrite, which could maintain good texture characteristics of the sausage. In addition, the total bacteria number of sausage containing peony extract and lactobacillus fermentation broth was significantly reduced (P＜0.05), which could prolong the shelf life of sausages to some extent. Compared with the blank control, the relative content of aldehydes and ketones decreased and the relative content of volatile flavor compounds such as acids and esters increased more significantly in compound sausage, in which the relative content of ethyl caproate increased 1.7 times. In addition, the relative contents of flavor substances such as 2-pentylfuran and maltol also increased, and its sensory evaluation was better.

Abstract:The differences were studied including color, tenderness, pH, protein degradation, and other indicators of beef and mutton at the best slaughter ages of cattle and sheep and the high and low-grade parts of the meat. Samples of longissimus dorsi (YH, NH) and abdominal muscles (YL, NL) of post-mortem Qinchuan beef and horizontal goat meat were taken for determination of pH, color, shear, sarcoplasmic and myofibrillar proteins, the solubility and degradation polymerization conditions. The results shown that the pH value of YL was significantly higher than that of YH (P＜0.05), there was no significant difference between the two parts of beef (P＞0.05), the pH value of mutton at the same part was significantly higher than that of beef (P＜0.05). The L^* values of the longissimus thoracis of beef and mutton were significantly higher than those of the external intercostals. The a^* value of YH was higher than that of YL, and the b^* value of NH was higher than that of NL (P＜0.05). The L^* value of mutton at the same part was significantly higher than that of beef. The a^* value of NL was greater than YL, and the b^* value was less than YL (P＜0.05). The shear force and myofibrillar protein solubility of the longissimus thoracis of beef and mutton were significantly less than that of the external intercostals, and the sarcoplasmic protein solubility was significantly greater than that of the external intercostals (P＜0.05). The mutton shear force and myofibrillar protein solubility of the same part were significantly lower than that of beef, and the sarcoplasmic protein solubility was significantly greater than that of beef (P＜0.05). The tenderness and color of the horizontal goat were slightly better than that of the Qinchuan beef. The degradation of the protein was slightly higher than that of the Qinchuan beef. The length of the longissimus dorsi of the cattle and sheep was better than that of the abdominal muscles, and the degree of protein degradation was higher than the abdominal muscles.

Abstract:Aiming at the problem of uneven heating of longan, excessive microwave drying rate and local over-focus, the vacuum microwave drying was carried out by the combination of intermittent microwave and variable power microwave. In this paper,the changes of water ratio and drying rate in the vacuum microwave drying process were analyzed, such as the power density, vacuum degree and loading quantity. Seven thin layer fitting models were tested. The orthogonal experiment of three factors and three levels for color, total phenolic content and rehydration evaluation was established. The optimum intermittent vacuum microwave drying process of longan was optimized. The results showed that the effective diffusion coefficient of the longanpresented rising trend with increasing power density and vacuum degree, and with decreasing loading capacity. Among the seven mathematical models, Two-term model was the best fitting one. The optimized intermittent vacuum microwave drying process of longan was under the condition of a power density of 12 W/g, vacuum degree of 90 kPa and loading capacity of 100 g.

Abstract:In order to explore the enhancing effect of contact ultrasound on hot air drying process, ultrasound enhanced hot air drying of pear slices was performed. The effects of different ultrasound powers and drying temperatures on drying characteristics and several quality indicators of pear slices were studied. The results showed that the improvement of hot air temperature and ultrasound power could significantly reduce drying time, and the stronger ultrasound enhanced effects could be achieved at lower temperatures. The BP neural network model was applied to predict the process of ultrasound enhanced hot air drying with high fitting precision. The cavitation and mechanical effects of ultrasound could increase moisture mobility and rehydration rate, and could improve the contents of the nutrients in pear slices. However, too high temperature was negative to the retention rate of total phenols, total flavonoids and ascorbic acid which were heat-sensitive nutrient components. The analytic hierarchy process was applied to determine the optimal parameters of ultrasound enhanced hot air drying of pear slices as hot air temperature of 35 ℃ and ultrasonic power of 48 W. The corresponding total phenol content, total flavonoid content, V_C content and rehydration ratio were 408.88 mg/100 g, 157.94 mg/100 g, 42.36 mg/100 g and 3.32, respectively. Therefore, the reduction of drying time as well as the improvement of product quality could be achieved with the application of contact ultrasound on hot air drying of pear slices.

Abstract:In order to understand the effect of salt on intestine microorganism, enzyme activities and blood in mice, and to provide scientific basis for daily rational use of salt for human beings, the KM mice were randomly divided into five groups of A, B, C, D, E group, each group with 6 rats of half male and half female. The mice was corresponding gavaged continuously for one month according to the conversion of clinical dose of 0, 3, 6, 9, 12 g, and then the mice was collected eyeball blood to blood routine analysis as well as the contents from jejunum to ileum to microbial and enzyme activity analysis. In the aspect of intestinal microorganism, the number of Escherichia coli in mice was significantly increased after gavaged different dose of salt (P＜0.01). The number of Lactobacillus and bacteria in group B had no significantly compared with group A, but increased significantly on the number of Bifidobacterium(P＜0.01); In the aspect of intestinal enzyme activity, the protease activity of the mice was inhibited after gived salt, and the amylase activity was higher by giving higher salt. The activity of protease and amylase in group B was decreased compared with group A, but they were closest to that of the group A, and the xylanase and cellulase activity of group B improved significantly compared with group A (P＜0.01 or P＜0.05); In the aspect of blood routine, mean platelet volume, platelet volume distribution width of group B, C, D or E decreased significantly compared with group A. The platelet count, red blood cell hemoglobin concentration, leukocyte count and lymphocyte count in the group B were the highest. The different dose of salt has different effect on intestine microbes, enzyme activities and blood in mice, and the effect of the dose according to adult 3 g was better than the rest of the dose.

Abstract:In order to improve the functional characteristics of egg albumin, taking the egg Ovalbumin (OVA) as the research object, the complex enzymes (papain, neutral protease and flavor protease) were used to modify OVA, and its functional and structural properties were analyzed. Taking the degree of hydrolysis (DH) as index, the optimum mass ratio of the complex enzyme (Papain∶neutral protease∶flavor protease) was determined to be 1∶1∶2. Based on the single factor, the enzymolysis conditions were determined by response surface methodology (RSM) and the optimum conditions were pH of 7.5, enzyme hydrolysis time of 7 h, OVA concentration of 5%, enzyme amount of 7 500 U/g, temperature of 56 ℃. Under these conditions, the degree of hydrolysis was (31.03±0.14)%. The effects of complex enzymolysis on the functional properties of OVA were analyzed. The results showed that its water holding capacity was increased by 1.65 g/g, the oil retention was reduced by 1.05 g/g, the surface hydrophobicity was reduced by 4.05%, and the turbidity was decreased significantly. The effects of enzymatic hydrolysis on the structural changes of OVA were analyzed by chemical reaction, fluorescence spectroscopy and scanning electron microscopy (SEM). The results showed that the primary structure of OVA was changed significantly, and its tertiary structure was also changed. In addition, the microstructure was transformed from spherical to lamellar structure.

Abstract:In order to study the quality change of fermented millet pepper, the sensory evaluation model of fermented millet pepper was established using the intelligent sensory instruments (electronic nose and electronic tongue) and sensory evaluation, combinating with the method of correlation analysis, principal component analysis, stepwise regression analysis and fitting test. The results showed that the weight of the simplified sensory indicators were 38.96%, 35.06% and 25.97%, respectively, and the fitting test R²=0.998 indicated that the model can replace the original evaluation method. Taking the PCA of the intelligent sensory index as the independent variable and the sensory evaluation model as the dependent variable, the principal component regression equation was established by factor analysis: Y (sensory score) =67.672＋8.296 × color PC1－1.571 × texture PC1－3.431× PC1 electronic nose＋0.288×PC1 electronic tongue, and the variance inflation factor test showed that the model had no obvious multicollinearity (VIF＜10). The new quality evaluation model can fit the change of sensory quality during fermentation process of millet pepper, and offset the defect of the reproducibility and stability of the artificial sensory.

Abstract:A comprehensive evaluation method of the aroma quality for menthol filter rod was established by using aroma ratio (B), aroma retention (L) and aroma quality (P) by referring to the flavor assessment methods in the food industry at home and abroad, sensory evaluation methods of cigarette. It was introduced into the evaluation of the period of mentholated holding in menthol filter rod. Through the sensory and quantitative evaluation of the aroma quality for menthol filter rod, the comprehensive score standard for judging the period of mentholated holding in menthol filter rod was determined, and a new method which was scientific, operative and simple, was established. Gas chromatography (GC) and gas chromatography-ion mobility spectrometry (GC-IMS) combined with sensory evaluation methods of cigarette were used to verify this method. The results showed that this method was suitable for the evaluation of the period of mentholated holding in menthol filter rod, which provided a basis for the determination and evaluation of the period of mentholated holding. Also, it provided reference for the design, quality control and inspection of menthol filter rod.

Abstract:Sichuan white goose is an excellent local poultry breed. In order to measure its nutritional value, the muscle amino acid composition of distinct body parts for Sichuan white goose of different age and gender was analyzed. In this study, hydrochloric acid hydrolysis was adopted for digestion of muscle protein and Hitachi L-8800 automatic amino acid analyzer was used to determine the content of amino acids. The results showed that 17 amino acids were detected in all muscle samples, among which the content of Glu was the highest, followed by Asp and Leu. We found that, of the three factors, age, gender and parts of body, age was the main factor affecting the amino acid content of Sichuan white goose. The content of various amino acids reaches their maximum between 180 days and 2 years, wherein the content of essential amino acids (EAA) was higher than the value recommended by FAO/WHO, but lower than that of whole egg. The ratios of EAA / NEAA and EAA / TAA were higher than the values recommended by FAO/WHO, which indicated that it was a good source of high-quality protein. The amino acid score (AAS), chemical score (CS) and essential amino acid index (EAAI) reached their highest values after 150 days of age. By evaluating either AAS or CS, we observed that the first-limiting amino acid was Val and the second-limiting amino acid was Phe+Tyr. These results suggested that Sichuan white goose meat has high nutritional value and good flavor, especially after 180 days of age.

Abstract:Key components of Antarctic Krill meals were analyzed such as protein, lipids, minerals and chitin content. Composition and content of amino acids, fatty acids and mineral element were also researched using nutritional assessment strategies in this paper. Finally, the protein processing base material was prepared by two steps include sieving and defatting. The results showed that the content of protein was 61.38%, lipids was 14.49%, chitin was 6.08% and mineral element was 6.27%. Protein of Antarctic Krill meals was a high quality protein referenced by FAO/WHO based on the total amino acid content of 47.34%, essential amino acid content of 38.74% and essential amino acids to non-essential amino acids ratio of 70.24%. Moreover, the functional amino acids content were also abundant. Lipids of Antarctic krill meal was found exploitable by polyunsaturated fatty acids content of 61.98%, polyunsaturated fatty acids content of 25.10% and EPA+DPA+DHA content of 18.19%. The functional minerals (K, Na, Mg, Ca, P, Fe, Cu, Zn, Sn) were found rich content and balanced composition in Antarctic krill, and the levels of heavy metal pollution (Cr, As, Cd) were extremely low simultaneously. The content of protein-peptides in processing base material is 70.91% by 30 mesh screening and degreasing with n-hexane-ethanol (9∶1), Which reached the quality standards of Antarctic krill meals, exceeded the evaluation criteria of special grade fishmeal and reduced 10% fluorine content of the system. The above results provided basic information and theoretical reference for protein production and byproducts utilization of Antarctic Krill meals.

Abstract:To understand the changes of the main nutrients and antioxidant activities of Rosa sterilis D.Shi during development. The changes of the main nutrients of Rosa sterilis D.Shi, including cellulose during development, reducing sugar, protein, ascorbic acid, total flavonoids, and total polyphenols, were investigated. The antioxidant capacity was analyzed by using the DPPH, ABTS, and FRAP. The antioxidant nutrients were determined by correlation analysis and principal component analysis. The results showed that there were differences in changes of nutrients and antioxidant activities of Rosa sterilis D.Shi during development. The content of cellulose and protein decreased with the development. The content of reducing sugar and ascorbic acid in Rosa sterilis D.Shi was consistent with the change trend of FRAP, which showed a continuous upward trend with the development. The total flavonoids content and DPPH maintained a high level in the development period. However, total polyphenols and ABTS of Rosa sterilis D.Shi increased first and then decreased with the development. Correlation analysis and principal component analysis showed that reducing sugar and ascorbic acid was the main antioxidant nutrients in Rosa sterilis D.Shi. Overall, the mature fruit of Rosa sterilis D.Shi has high nutrients and antioxidant activities.

Abstract:High performance liquid chromatography(HPLC) was developed to detect the hydrolyzed amino acids and free amino acids in grape seeds with phenyl isothiocyanate(PITC) as the derivative reagent. For chromatographic analysis, a Thermo Acclaim^TM 120 C₁₈ column (250 mm × 4.6 mm, 5 μm) was used. The mobile phase consisted of solvent A and B with the flow rate of 1.0 mL/min by gradient elution. Solvent A was sodium acetate buffer solution (pH 6.5) and solvent B was methanol-acetonitrile-water (20∶60∶20, v/v/v). The temperature of column was maintained at 30 ℃. The wavelength was set at 254 nm. The results showed that the R² of 17 kinds of amino acids were more than 0.999 0 in the range of experimental concentration. The average recoveries of hydrolyzed amino acids were 92.0%～104.6%, and RSDs were 0.83%～4.07%. The average recoveries of free amino acids were 95.2%～102.4%, and RSDs were 1.06%～3.98%. The contents of hydrolyzed amino acids in 6 kinds of grape seeds were 130.46～163.24 mg/g. The contents of free amino acids were 2.04～5.13 mg/g. More free amino acids were contained in the grape seeds from Leisiling, Saimeirong and Guirenxiang which three kinds of grape seeds were usually used to brew the white wine. The contents of hydrolyzed amino acids were higher in the grape seeds from Heipinuo, Shelongzhu and Chixiazhu which were always used for the red wine brewing. The method was stable and reliable, can be used for the determination of hydrolyzed amino acids and free amino acids in grape seeds.

Abstract:The 13 nm gold nanoparticles were synthesized and were modified with Bisphenol A(BPA) aptamer. The oil-solubility Up-conversion nanoparticles (UCNPs) were modified with polyacrylic acid (PAA) to form water-solubility UCNPs. Then water-solubility UCNPs were coated with the complementary DNA strand. Based these nanoparticles, a FRET aptasensor for BPA was successfully fabricated by using Up-conversion nanoparticles as energy donor and gold nanoparticles as energy acceptor. The results show that the detection system has a good linear relationship at 1×10^-9～1×10^-3 mol/L (R²=0.992 3), and the detection limit is as low as 1×10^-10 mol/L. The method is proved to be of good practicability through the experiment of adding the standard of water and milk samples.

Abstract:Developed a qualitative and quantitative analysis method which simultaneously determined nine kinds of pesticide residues in dark tea by gas chromatography in combination with triple quadrupole mass spectrometry. After being extracted by acetonitrile and purified by Cleanert TPT solid-phase extraction column,they were analyzed by GC-triple quadrupole MS.The results showed that the calibration cure for nine kinds of pesticide was the linear in the range of 0.4～3.2 mg/L and peak area,each correlation coefficient is above 0.99,and the relative standard deviation(RSD) was between 1.5% and 5.6%. At the same time, the average recovery was ranged from 81.6% to 98.6%,and the determining limits are below 1.0 μg/kg. This method which has advantages in great efficiency of separation, high accuracy, good reproducibility and easy and fast for operation.

Abstract:Two different methods for the determination of three kinds of sugar alcohols in bubble gum and beverage were analyzed and compared. Samples were extracted directly by water. Half part of the extracts was detected by high performance liquid chromatography with differential refractive index detection (HPLC-DRID), the rest part of the extracts was detected by high performance liquid chromatography with evaporative light-scattering detection (HPLC-ELSD). Limits of detection (LOD) of xylitol, sorbitol and maltitol determined by HPLC-DRID were 0.037 5 g/100 g, the correlation coefficients were in the range of 0.999 21～0.999 29, and the recovery rates of spiked samples were in the range of 91.5%～97.3%; LODs of xylitol, sorbitol and maltitol determined by HPLC-ELSD were in the range of 0.009 5～0.027 5 g/100 g, the correlation coefficients were in the range of 0.999 3～0.999 6, and the recovery rates of spiked samples were in the range of 90.9%～96.3%. All results showed that both of HPLC-DRID and HPLC-ELSD were the appropriate methods for the determination of three kinds of sugar alcohols in samples. Compared with HPLC-DRID, the HPLC-ELSD is a more optimal method for the sample with low sugar alcohols contents because of its high sensitivity in the test.

Abstract:UPLC-UV-QDa technique, combined with the acidic hydrolysis experiment were applied to quantitative and qualitative analysis flavonoid aglycones and methanol extracts from leaves of four different kinds of Prunus cerasifera. The result showed that quercetin and kaempferol were well separated in 7.0 minutes and had good linear relationship, the average recoveries of two flavonoid aglycones were 98.65% and 102.02% with RSD 1.08%(n=3) and 1.17%(n=3), the method was proved to be fast, accurate and repeatable. There was some difference in the content of flavonoid aglycone from different kinds of Prunus cerasifera in different environment, two flavonoid aglycones were found in all kinds of leaves, while kaempferol was the main composition. The content of kaempferol was the highest in leaves of purple fruit in sunny slope up to (7.68±0.45) mg/g, and the lowest in leaves of red fruit in valleys with (4.59±0.32) mg/g, the content of total flavonoids were from 16.21 to 33.25 mg/g. Composition of extracts from leaves of purple fruit in sunny slope were rapidly identified by UPLC-UV-QDa technique, including one caffeoylquinic acid, four quercetin glycosides and seven kaempferol glycosides. The above results provide theoretical support and technical basis for the further exploitation and utilization of Prunus cerasifera.

Abstract:According to the shortcomings of current food traceability system on account of inconsistency in technological standards, non-transparency in information, liability to be tampered, serious centralization and information islands, this paper explores the key standards and technologies of food traceability, establishes a traceability system structure and designs a food traceability process based on Internet of Things and blockchain. By adopting the alliance blockchain model and the Hyperledger development platform, implemented a traceability prototype system. It fully demonstrates that our technological solution can significantly improve efficiency and transparency of the food supply chain, which will obviously enhance the food safety and rebuild the consumer’s confidence in the food industry.

Abstract:In view of the complex and time changing characteristics of the fluid domain in the twin screw compressor, and in order to study it’s performance characteristics in detail, used STAR CCM＋software to do the computational fluid dynamics (CFD) analysis, and the experimental platform was built to verify the accuracy of the simulation results. By comparing the pressure values of the simulated monitoring points and the experimental measured points corresponding to them, both of them have good consistency in the pressure value and the period of pressure fluctuation.

Abstract:The transmission shaft connecting CH and CV in GDX2 packer always breaks down due to attrition. Its integrated design and small repair space make it time-and-energy consuming to replace the damaged transmission shaft, which inspires us to improve itsuniversal joints. Based on its original transmission principle, we substitute the fast respectively demountable units for the transmission gear, which made the installment more efficient. While repairing, only the broken units needed to be beplaced. The application result showed that the improved universal joints function reliably, with less labors, and greatly increased the effective operation rate because of its simple structure.

Abstract:In view of the blank current situation of automatic sandwich making and selling equipment in the market, a new sandwich making and selling machine is developed. The design and manufacture of the whole new mechanical machinery body, vegetable throwing device, and loaf pushing device, etc. have been completed. The prototype has been tested and run. The functions of personalized meal selection, scavenging payment, cash payment, heating and cooling and disinfection, multi station feeding synergy, network monitoring and management are realized.

Abstract:In view of the current market common kitchen waste composting box is not easy to keep warm, the composting time is long, the effect of drainage is poor, the odor is heavy and so on. A small household composting box is designed and its spatial structure is designed and optimized. The device includes several modules, such as solar collector, solar panel, ventilator, feeding port, leachate screen, tail gas treatment and so on. It can better meet the requirements of high temperature aerobic composting process. It uses solar energy for the whole system of heat preservation, ventilation and energy supply, reducing energy consumption. Compared with natural composting, composting time is shortened. The whole system is easy to move and is not restricted by the place of placement. It is very suitable for use in the courtyard.

Abstract:The mildew of stored grain will affect the safety of food，which can be monitored by the method of detecting the change of carbon dioxide (CO₂) concentration in grain bulk. As an indirect method, it is necessary to analyze comprehensively the related factors of grain bulk and the parameters of CO₂ sensor, which cansignificantly affect the detection value. The results showed that the mould count in the initial stage of the stored grain fungi growth was synchronized with the change of CO₂ concentration at different temperatures, and the correlation coefficient was greater than 0.99. CO₂ production decreased significantly at low temperature, the CO₂ produced at 30 ℃ was 4.7 times higher than that at 20 ℃ in the grain bulk of similar mould count. CO₂ gas diffusion was significantly affected by grain porosity and other factors. The porosity of rice was 30% higher than that of wheat, but the peak concentration of grain pile at the monitoring point 50 cm from the source of CO₂ was 50% higher than that of wheat pile, with 4 days earlier of the peak time. The monitoring point of 3 m below surface of grain bulk ccould reduce the effect of external gas exchange, and the monitoring effectiveness was better than that of the monitoring point with depth of 1 m when mildew position at 1 m or 2 m from grain bulk surface. The gas flow velocity and sampling quantity should be determined in the process of gas detection, and the detection value ccould be significantly reduced when the gas flow velocity exceeded the specified flow rate, and the gas sampling volume should be 1.5 times of the theoretical volume in the pipeline. Therefore, the carbon dioxide detection method by setting parameters reasonably could sensitively monitor the activity of mould in stored grain, and this was practically valuable for high efficiency in preventing and controlling the damage of mould.

Abstract:In order to prolong the shelf life of kumquat, kumquat fruits were treated with coating preservation of litsea cubeba essential oil and chitosan, then stored at room temperature conditions, the changes of weight-loss rate, soluble solids, titratable acid, vitamin C(V_C), total sugar, sensory index in fruits during storage were investigated. The results showed that the composite coating of Litsea cubeba essential oil and chitosan inhibited the weight-loss of the kumquat, soluble solids, titratable acid, V_C, total sugar and sensory of the treated group were better than the control group. The weight-loss rate, soluble solids, and V_C were all significantly different. At the 30th day, the weight-loss rate of the treated and control groups were 5.92% and 8.35%, the soluble solids were 10.31% and 8.67%, the V_C were 15.77 mg/100 g and 8.32 mg/100 g, respectively. The composite coating of Litsea cubeba essential oil and chitosan reduced the consumption of nutrients, effectively retarded the aging of kumquat and provided a theoretical basis for its application in fresh food preservation.

Abstract:Aiming at the shortcomings of traditional apple defect detection methods such as high labor intensity, low productivity and high false positive rate,the apple defect detection algorithm is proposed based on visible light-infrared light image fusion. The algorithm uses different fusion methods for high and low frequency wavelet coefficients of visible and infrared images to obtain more prominent feature images. The results of simulations show that the recognition rate can reach 96% in the detection of apple fruit with scratches, bumps, fruit stems/flower buds and intact fruits, in addition, the recognition accuracy rate for scratches can reach 92%, and in the detection of fruit stems, flower buds and intact fruit, the accuracy rate can reach 100%. It fully meets the needs of apple's online detection and classification.

Abstract:The study was to accurately evaluate the quality of table grape,18 different varieties of table grapes were selected. 14 basic quality indicators were measured and analyzed by sensory scores and correlation analysis. Principal component analysis was employed to build a composite score mathematical model. The results showed that there was a significant difference in the quality indexes among different grape varieties, among them, hardness difference was largest (coefficient of variation is 51.18%). Correlation analysis showed that there was an independence and a certain degree of correlation between indicators. Principal component analysis was extracted from 4 principal component factors, and cumulative contribution rate reached 88.63%. The comprehensive score comfirmed that the best grape was Black Grape, Shine-Musca, Wink and Jumeigui; The quality of Kyoho Grape, Ruby Seedless and Gold finger were relatively poor.

Abstract:Protamex and alcalase were synergistically used for hyolorlysis of corn protein and the hydrolysates were glycosylated with oligochitosan by Maillard reaction. The antioxidant activities of corn protein hydrolysates (prepared under different protein/enzyme rattios) and glycosylation products were studied. The resultsshowed that both of the enzymatic hydrolysates and glycosylation products had good antioxidant activity, and-the Maillard glycosylation reaction could improve the antioxidant activity of corn hydrolysates. When the protein concentration of glycosylation products was 5 mg/mL, clearance rate of·OH and DPPH· reached to 90.91% and 90.91%, respectively,which increased 48.78% and 32.26%, compared to non-glycosylated hydrolysates.Similarly,when the protein concentration of glycosylation products was 1 mg/mL, ferrous chelating capacity was 83.42%, compared to hydrolysates,which increased 22.63%.

Abstract:The polysaccharides from Zingiber officinale Rosc were extracted by hot water extraction method, ultrasonic ice bath extraction method and complex enzymatic hydrolysis method. The effects of different methods on the extraction were investigated by the UV spectra image and the scanning electron microscope image of ginger residue. The results showed that the polysaccharides extraction rates of the three different extraction processes under optimal extraction conditions were (11.74±0.23)%, (7.00±0.04)%, and (20.93±0.20)%, and the yields were (6.53±0.08)%, (2.56±0.11)%, and (14.67±0.32)%, the purity was (86.53±0.20)%, (59.84±0.06)%, and (73.59±0.19)%. Comparing with three different methods, the enzymatic hydrolysis method had the highest extraction rate and yield of Zingiber officinale Rosc polysaccharides, but in terms of purity, the hot water extraction method was the best. According to the TEM image of ginger residue, found different extraction methods had different degrees of damage to Zingiber officinale Rosc cells, resulting in different extraction rates and yields of polysaccharides.

Abstract:The Optimization of the extraction of polyphenols from Porphyra haitanensis and their antioxidant and antimicrobial activities in vitro were studied. The effects of liquid-material ratio, ultrasonic times and ethanol concentration on the contents of polyphenols from P. haitanensis were investigated. Moreover, the response surface analysis method was applied to determine the optimization of the extraction. The results showed that the optimum condition for the ultrasonic-assisted extraction of polyphenols was as follows: liquid-material ratio 35∶1 (mL/g), ultrasonic times 43 min and ethanol concentration 66%. Under the optimum condition, the contents of polyphenols was (6.85±0.13) mg GAE/g. The research of their antioxidant activity in vitro showed that the polyphenols had the scavenging capabilities of DPPH and ABTS radicals, and their IC₅₀ were (36.67±0.75) and (16.07±0.32) μg/mL, respectively. The value of oxygen radical absorbance capacity (ORAC) was (1 005.1±11.8) μmol TE/g. Meanwhile, their antimicrobial activity in vitro showed that the polyphenols could inhibit the growth of tested microorganisms including Escherichia coli, Staphylococcus aureus, Bacillus subtilis and Sarcina lutea, and their minimal inhibitory concentrations were 1, 1, 1， 2 mg/mL, respectively.

Abstract:The optimization of the flavonoids extraction technique of Coreopsis tinctoria Nutt tea and the vitro antioxidant activity of flavonoids was studied by taking the Coreopsis tinctoria Nutt tea as the raw material, and basing the single factor experiment and Box-Behnken methodology. Results:The optimal extraction conditions of flavonoids from Coreopsis tinctoria Nutt tea were: extraction time 13 min, extraction temperature 98 ℃, the ratio of solid to liquid 1∶78 (g/mL). Under the conditions, the flavonoids extraction rate was (20.39±0.07)%. The half inhibiting concentrations (IC₅₀) to FRAP and DPPH free radical scavenging were (137.98±1.56) μg/mL and (82.40±1.98) μg/mL, respectively. The ORAC value was 1 427.89 μmol TE/g·DW, which indicated that the flavonoids from Coreopsis tinctoria Nutt tea exhibited significant antioxidant activities in vitro.

Abstract:In this study, the bioactive compounds of 6 common edible flowers were extracted by ultrasonic extraction method and their antioxidant activities were assessed. The content of flower active ingredients such as polyphenols, flavonoids, anthocyanins and carotenoids were determined by ultraviolet spectrophotometry and HPLC. The content of these active compounds range from 6.20～63.17 mg GAE/g ·DW, 12.52～180.47 CE /g· DW, 4.17～40.91 mg CyA/g· DW and 0.33～0.68 mg/g ·DW, respectively. The antioxidant activities were assessed by DPPH, FRAP and ABTS assays, range from 45.13～1 092.49, 100.20～2 621.25 and 100.12～1 708.03 μmol TE/g DW respectively.

Abstract:Ultrasonic-assisted hydrodistillation extraction (UAHE) essential oil from lemon peel was investigated. On the basis of single-factor test, response surface methodology was applied to optimize the parameters of extraction, including ultrasonic power, solvent to material ratio, ultrasonic time, and distilling time on the yield of essential oil. Meanwhile, the volatile composition was analyzed by GC-MS. In addition, the microscopic structures of material before and after various extraction methods are observed to clarify extraction mechanisms. The optimal extraction conditions were ultrasonic power of 320 W, solvent to material ratio of 15.5∶1 (mL/g), ultrasonic time of 36 min, distillation time of 140 min. Under this condition, the oil yield was up to 1.97%. Totally 26 compounds were identified accounting for 96.16%, of which limonene was the major constituent. Scanning electron microscopy revealed that ultrasonic technique efficiently promoted the release of essential oil by breaking down the cell structure of lemon peel. Moreover, essential oil extracted by UAHE was quantitatively (yield) and qualitatively (chemical composition) similar to those obtained using hydrodistillation extraction. Therefore, UAHE essential oil of lemon would be an effective method.

Abstract:The paper describes the luminescent bacteria and the mechanism of detecting toxic and harmful substances. This paper reviews the recent advances in the application of luminescent bacteria in toxicity assessment and food safety testing. What’s more, the factors influencing the application of luminescent bacteria in food safety testing are pointed out, and the paper indicates the application research direction in this technical field.

Abstract:The spoilage of aquatic products is mainly caused by microbial activities. In this paper, the Specific Spoilage Organisms (SSO) in aquatic products, Quorum Sensing (QS) signal of microbial molecules, the resource and function methods of QS inhibitors were described, respectively. The existing problems and solutions of current QS inhibitors from plant were proposed as well so as to provide the theoretical reference for the research of preservatives for controlling the QS in aquatic products.

Abstract:Based on the new achievements in the study of the trace components of traditional Chinese liquor, its sources and effects were systematically summarized for the first time. The main sources are three ways: catalytic reactions of microorganisms and enzymes during fermentation, chemical changes during storage, and chemical reactions of special components from raw materials, and which mainly playes three roles: the aroma and flavor-producing, style and aroma type-forming and physiological functions. In the future, the research focuses on the impact of raw materials on the trace components of traditional Chinese liquor, the construction and application of gene bacteria of high-yielding liquor main flavor components, and the in-depth study of liquor functional factors, providing a more complete theoretical basis for the comprehensive and profound understanding of Chinese liquor.

Abstract:Anoectochilus roxburghii polysaccharide (ARP) is a kind of bioactive substance, consisting of monosaccharides polymerized by glycoside bonds. It is extracted from Anoectochilus roxburghii and has effective functions to decrease blood sugar and blood fat, and to protect liver and kidney. It also has excellent effects on sleep promotion, anti-tumor, and immunity enhancement. Based on the research of ARP in recent years, this article reviewes the extraction methods of ARP and mechanism of its biological activity, briefly analyzes the characteristic of its structure, and summarizes the differences in the content of different sources of ARP and the application of ARP in foods.

Abstract:The natural apricot powder was prepared by microwave drying (MD), hot air drying (HAD), microwave vacuum drying (MVD) and microwave convection drying (MCD) and their nutritional, physical, sensory and antioxidant propertieswere compared. Significant differences among the determined quality terms of the four products were observed（P＜0.05）, the MVD and MCD products had the higher total sugar and reducing sugarand the latter had the least loss in total phenol and V_C content while the HAD product the best retention of total acid, the apricot meat powder prepared by MD had the lowest hygroscopicity and caking degree. The apricot meat powder prepared by MCD method had the smallest bulk density and repose angle and the highest sensory score（95.2）. The ability of reducing power, scavenging DPPH, superoxide anion and hydroxyl radical of apricot meat powder showed a significant quantity-effect dependence. The apricot meat powder prepared by MVD showed the strongest DPPH radical scavenging ability while the apricot meat powder by MCD had the highest hydroxyl radical (88.5%) and superoxide anion radical scavenging capacity (85.1%) as well as the maximum reducing power (1.98).

Abstract:In order to enhance the nutritive value and functional activity of quinoa, response surface methodology was employed to optimize the fermentation technology based on the single factor experiment to increase the total phenols. Moreover, the antioxidant and α-glucosidase inhibiting activity of quinoa were compared. The results showed that the optimal fermentation conditions were as follow: yeast 1.7%, fermentation time 80 h, moisture content 16 mL, and the average content of total phenols from fermented quinoa was reached to (5.31±0.11) mg/g under these conditions, which was close to the predicted value with the relative error is only 1.12%. Moreover, compared to unfermented quinoa, the fermentation treatments could obviously increase the content of total phenols, especially quercetin and vanillic acid, which reached to (113.4±8.73) mg/kg and (44.7±2.54) mg/kg, respectively. The activity assay indicated that the scavenging activity against DPPH and ABTS free radicals of the fermented quinoa were remarkably increased, with the IC₅₀ were 16.42 mg/mL and 1.51 mg/mL, respectively. Meanwhile, the α-glucosidase inhibiting activity was averagely increased 12.41%. Therefore, the fermented treatment of quinoa could obviously increase the content of total phenols, and enhance its nutritive value and biological activity.

Abstract:Effects of the addition amount of different thickeners (maltodextrin, xanthan gum, sodium carboxymethyl cellulose) on the quality of freeze-dried Pleurotus eryngii powder were studied by investigating the indexes of bulk density, hygroscopicity and instant solubility. In order to obtain a better product quality, the best combination of thickeners was optimized by single factor, orthogonal experiment and comprehensive analysis method. The results showed that adding three thickeners alone can improve the quality of freeze-dried Pleurotus eryngii powder. The effect of maltodextrin was the most significant, followed by xanthan gum and sodium carboxymethyl cellulose. The best combination was maltodextrin 15%, xanthan gum 0.15% and sodium carboxymethyl cellulose 0.8%.

Abstract:With the activated carbon iodine adsorption and yield as the optimization index, the process of Suaeda sasla carbon taking H₃PO₄-ZnCl₂ as the dual activator was studied. The single-factor test was used to examine the effect of mass fraction of H₃PO₄-ZnCl₂, activation temperature, and the activation time on activated carbon preparation. The optimum conditions for the preparation of S. sasla based activated carbon by orthogonal experiments were as follows: H₃PO₄-ZnCl₂ mass fraction 30%, activation temperature 500 ℃, activation time 80 min. Under these conditions, the iodine adsorption value and yield of the Suaeda carbons were 865.45 mg/g and 43.39%。