Abstract:Tofu is a gelatinous curd formed by adding coagulant to the heat treated soybean milk.The gelation of tofu is the gelation of soy protein, and that is a key part of tofu processing. So soybean protein is closely related to tofu quality characteristics. The tofu formation mechanism and the effect of protein content and components on the quality of tofu were summarized, in order to further clarify the relationship between soybean protein and tofu quality characteristics, improve the properties of tofu gel, and provide the theoretical basis for improving and promoting the tofu quality.

Abstract:Sweeteners, an important food additive, are indispensable in the modern food production industries and can be applied to a variety of foods. Despite the continuous development of safety standards and regulatory systems for food additives in China, some producers still blindly pursue profits due to the rapid development of the sweetener industry. Therefore, there are still a lot of problems about use and production of sweeteners, such as over-and out-of-range use of sweeteners, abuse of complex sweeteners, several sweeteners using together, nonconforming labeling, unacceptable qualities of sweeteners, and masking of food quality defects or doping with sweeteners for adulteration and forgery. Food producers should reasonably regulate the production and use of sweeteners to avoid the harm to consumers' health. Consumers should also rationally perceive sweeteners, purchase products from regular channels, and have rational diet.

Abstract:Artificial sweeteners (AS) are favored by food manufacturing markets and consumers due to their high sweetness, low prices and low calories. At present, 9 kinds of AS are approved in more than 10 categories of food and beverages in China. However, the emerging animal experimental and epidemiological studies have shown that long-term and high consumption may lead to metabolic diseases including hyperglycemia, glucose intolerance and obesity, and cause nervous system abnormalities such as irritabi-lity, depression, memory decline and Alzheimer's disease. Moreover, some AS even are linked to genotoxicity and carcinogenicity. Given the possible health risks of AS, it is necessary to control AS consumption, or to develop new AS with a tendency. Meanwhile, the further safety studies regarding new AS should be enhanced.

Abstract:The yeast with strong ability producing ester was isolated by biochemical reactions in plate from Sichuan bran vinegar starter and identified by 18S rDNA homology analysis. The growth characteristics such as optimal growth pH, alcohol tolerance, assimilation capacity to carbon sources, and nitrogen sources were studied. And metabolites were studied by solid phase microextraction plus GC-MS techniques. The result showed that the yeast isolated from ester transparent ring experiment was Wicherhamomyces sp. Lzcq 2014. The optimal growth pH was about 5.0 to 5.5, and it didn't grow when the alcohol content was 10%. Meanwhile, the ability assimilating carbon source in desending order was glucose, sucrose, maltose, lactose, and starch, and the ability assimilating nitrogen source was yeast extract, peptone, ammonium sulfate, and urea. The main metabolite was ethyl acetate, and the concentration reached 0.64079mg/L. The contents of isoamyl formate, propanoic acid, and phenylethyl alcohol, were 0.04136,0.03943,0.02300mg/L, respectively.

Abstract:Zearalenone (ZEN) is a kind of fungal toxin produced mainly produced by Fusarium, which can easily contaminate food crops. Using the specificity of biological enzyme to destroy the molecular structure of ZEN is an effective method to eliminate ZEN pollution. Through screening, we found a microbial strain that can efficiently degrade ZEN, and the whole genome sequence information of the strain was obtained by the genome sequencing. The sequence alignment of ZEN-degrading enzyme ZHD101 was then performed, and the homologous sequence ZHD795 was obtained. To determine its ZEN-degrading activity, the gene fragment was synthesized chemically and cloned into the E.coli expression system, and the protein was then purified using affinity chromatography. The degradation activity was tested and the HPLC results showed that ZHD795 could degrade ZEN molecule efficiently. At the same time, the level of ZEN degradation activity of ZHD795 and ZHD101 was compared. Under the same conditions, the degradation activity of ZHD795 to ZEN was 2.5 times than that of ZHD101. This research showed that a highly active ZEN degradation enzyme with good application prospect was obtained.

Abstract:In this paper, effects of glycerol on the synthesis and related genes expression of Monascus CG-6 Monacolin K were studied. The yields of Monacolin K and related genes expression were determined by high performance liquid chromatography and real-time PCR. The results showed that the accumulation of intracellular and extracellular Monacolin K increased first and then decreased with the increase of gly-cerol concentration in the range of 0-12% after 9 days of culture. When the concentration of glycerol was 8%, the accumulation of intracellular and extracellular Monacolin K reached the maximum, which was 9474.4μg/g and 7005.8μg/g dry weight. With the prolongation of culture time, the expression of mokA, mokD, mokE, mokG, mokH, and mokI of Monacolin K synthesis genes increased gradually compared with the control group, while the expression of mokB and mokC did not change much, and the expression of mokF decreased gradually; When glycerol concentration was greater than 8% for 9 days, mokB, mokC, mokD, mokE, mokF, mokG, and mokH showed a downward trend. The results provide a reference for studying the effects of carbon sources such as glycerol on the synthesis of secondary metabolites and the expression of related genes in Monascus.

Abstract:Effects of different vegetable oils, such as rice bran oil, sesame oil, and soybean oil, on flavor, texture, sensory quality, and volatile flavor components of japonica rice were investigated. The results showed that edible oil addition significantly increased the hardness and elasticity of rice and reduced the viscosity. During the range of 0-100μL oil/(50g) rice, hardness and elasticity of rice were significantly increased while viscosity was decreased with the increasing addition of rice bran oil. Compared with the control group, the total content of volatile flavor components were reduced by 65.77%, 59.75%, and 74.79%, respectively after adding rice bran oil, sesame oil, and soybean oil. Based on microstructures of rice grains, the addition of edible oil inhibited the volatile release of volatile flavor substances in rice. The sensory evaluation results showed that the addition of edible oil weakened the aroma of rice and retain more flavor substances inside rice grains, making the taste of rice mellower.

Abstract:Artificial antigens against rosin were synthesised with dehydroabietylamine(DHAM) as a hapten, and the multi-clonal antibody was prepared by immunizing New Zealand rabbits. At first, DHAM was reacted with succinic anhydride (SUC) followed by being conjugated to bull serum albumin (BSA) and keyhole limpet haemocyanin(KLH). The artificial antigens (DHAM-SUC-BSA and DHAM-SUC-KLH) were synthesised, and the ratios of conjugation were 21 and 35. Multi-clonal antibody was raised in New Zealand rabbits by injection of DHAM-SUC-KLH, and the titre reached 1.28×10⁵. The IC₅₀ of dehydroabietic acid (DHA) and abietic acid (AA) were 25.1μg/L and 36.4μg/L. The result indicated that the immune antigen was a desired immunogenicity and the multi-clonal antibody showed a good sensitivity against DHA, which paved a way for building enzyme-linked immunosorbent assay (ELISA) of rosin residue in animal products.

Abstract:This research studied the potential of several marine Lactobacillus strains as biopreservative for yellow croaker fish preservation. The results showed that the strains Y12, Y3-1, and Y42 had the stronger antibacterial activities against Listeria monocytogenes, Salmonella enterica, Staphylococcus aureus, Vibrio parahaemolyticus, Serratia marcescens, Acinetobacter spp., and Pseudomonas spp.. There was no significant difference (p>0.05) between the TVBN contents of the freshly-cut fish meat inoculated with the strains Y12, Y3-1, and Y42 and that of the un-inoculated fish meat stored at 4℃ for 8 days, indicating that the strains Y12, Y3-1, and Y42 had no spoilage potential for fish meat. The TVBN values and pH values of sterilized fish juice inoculated with the strain Y12 and Pseudomonas spp. were significantly lower (p<0.05) than those of the sterilized fish juice inoculated with Pseudomonas spp., and the sensory evaluation score of the fish juice co-cultured with two strains was higher than that of the juice inoculated with Pseudomonas spp. alone. The TVBN value of fresh fish meat inoculated with the strain Y12 and Pseudomonas spp. was significantly lower (p<0.05) than that of the fish meat inoculated with Pseudomonas spp.. The results indicated that L. plantarum Y12 had antibacterial and anti-spoilage effect in fish meat.

Abstract:This study evaluated the effects of transport time on stress level and meat quality of Yangzhou goose. Thirty Yangzhou geese were randomly assigned into five treatments with each group having six geese. Transport time with 0,1, 2,3 and 4h was considered as the main factor among which 0h treatment was the control group. The results showed that the contents of adrenocorticotropic hormone and glucose after 2h transport were significantly higher than those of other treatments (p<0.05). After 2h transport, the level of lactic acid in the blood was significantly decreased (p<0.05). The activities of creatine kinase and the plasma lactate dehydrogenase after 2h transport were higher in the control group and 4h transport group (p<0.05). In terms of energy metabolism, the level of lactic acid of breast meat in 2h transport group was higher than the control group, 1h transport group, and 4h transport group (p<0.05). The pyruvate kinase and hexokinase activities in the treatments with 2h transport were higher than the control group and 4h transport group (p<0.05). The content of ATP decreased with the increase of transport time. After transport, the content of ATP was significantly lower than that of the control group (p<0.05). The levels of ADP and AMP increased with the increase of transport time. After 3h and 4h transport, the content of ADP was significantly higher than that of the control group (p<0.05). The level of AMP in the treatments with 2-4h transport was significantly higher than the control group (p<0.05). After 1h and 4h transport, the content of IMP was significantly higher than that of the control group (p<0.05). In terms of meat quality, L* of goose breast and the shear stress after 2h transport were higher than other treatments (p<0.05). a* in the treatment with 2h transport was lowest among all the treatment groups. After 2h transport, the level of stress in Yangzhou goose was highest and the meat quality was significantly decreased.

Abstract:Tartary buckwheat seedlings after germination contain abundant beneficial ingredients, especially flavonoids. In this study, tartary buckwheat seedlings and buckwheat tea juice were fermented by Lactobacillus plantarum. The fermentation conditions and formula were optimized by single factor and response surface optimization experiments, and the flavonoids content, light transmittance and pH of pro-ducts were determined. The results showed that the optimal ratio of tartary buckwheat seedlings to tartary buckwheat tea juice was 1∶6, and the dilution rate of better supernatant was 1∶10. And the total flavonoids content of products could reach (0.193±0.006)mg/mL. The optimal fermentation conditions were 0.6% microbial inoculum, fermentation time 24h, and 6% fructose-glucose syrup. Under this condition, the average sensory score of product was 91.50±0.29 and the optimum pH value was 3.87±0.05. The best stabilizer formula of this beverage was 0.06% xanthan gum, 0.08% CMC-Na, and 0.05% sodium alginate. Under this condition, the average sensory score was 93.60±0.32 and the transmittance was 91.37%±0.45%. After fermentation, this beverage is rich in flavonoid probiotics, and other beneficial ingredients, which had a mellow taste, clear and unique flavor.

Abstract:Watermelon peel accounts about 30% of the total weight of the fruit, which is a byproduct of the processing of watermelon. The chlorophyll of the peel was extracted via the solvent extraction method and ultra high pressure assisted solvent extraction method with the peel as materials. The parameters of the solvent extraction method and ultra high pressure assisted solvent extraction method were optimized and compared. The optimum solvent extraction method extracted the peel via 80% acetone at 50℃ for 1.5h with the solid-liquid ratio of 1∶7g/mL and acquired the chlorophyll yield of 3.92mg/g. The optimum ultra high pressure assisted solvent extraction method extracted the peel via 80% acetone at high pressure of 40MPa for 10min with the solid-liquid ratio 1∶7g/mL, and acquired the chlorophyll yield of 4.46mg/g. Hence, the ultra high pressure assisted solvent extraction method reduced the extraction time for 90% and enhanced the chlorophyll yield of 11.7%, which provides a technical solution for utilization of watermelon byproducts.

Abstract:Exogenous pectin methylesterase was added to low-salted pickled cucumbers. The single-factor experiment and orthogonal test were used to study the amount of calcium lactate and pectin methylesterase added, the enzymatic temperature and the enzymatic action time on low-salt pickled cucumbers.The optimal conditions for the action of exogenous pectin methylesterase were optimized by using the full texture hardness as an indicator. The results showed that the optimized reaction conditions of pectin methylesterase were the calcium lactate addition 0.40g/mL, the enzyme addition 0.40%, the enzyme reaction temperature 50℃, and the enzyme action time 20min. The effects of exogenous pectin methylesterase on the pectin content and texture properties of low-salted pickled cucumbers under optimized conditions were studied. The results showed that the addition of pectin methylesterase improved the texture properties of low-salted pickled cucumbers.

Abstract:In order to realize the fast lossless field detection of apple sugar by portable near infrared spectrometer, the K-S algorithm was used to divide the sample set. The partial least square and the interval partial least square algorithm was used to determine the optimal wavelength range of apple sugar. After compared and analyzed 9 pretreatment combinations, apple sugar's near-infrared prediction model was set up. The results showed that the optimal sugar range was 1198-670cm-1 using the partial least square method, and the model with first-order derivation, S-G convolution smoothing, and standard normalization was the best predictor. The correlation coefficients and RMSEC of the correction set were 0.9223 and 0.423, and the correlation coefficients and RMSEP of the prediction set were 0.9189 and 0.237. The results showed that the apple sugar could be detected quickly and lossless by using the portable spectrometer with low accuracy.

Abstract:In order to explore the differences between lead isotope and related elements in organic farming and conventional culture, the possibility of traceability of organic chicken samples was explored. In this study, two different feeding methods, organic farming and conventional breeding, were used for the same breeds of chickens. The lead isotope ratios and related element contents in organic chicken and common chicken samples were determined by inductively coupled plasma mass spectrometry. The results of variance analysis showed that the lead isotope ratios of ²⁰⁴Pb/²⁰⁶Pb and contents of P, Zn, Fe, Mn, Mg, Ca, Cu, Na, K were significantly different (p<0.05). The principal component analysis showed that Zn, Mn, Mg, Ca, Cu, Na, and K were characteristic inorganic elements in organic chicken and common chicken samples. Meanwhile, cluster analysis could divide chicken samples into two categories:organic farming and conventional breeding, and the initial group correcting rate obtained by discriminant analysis was 100.0%, and the cross validation accuracy was 90.0%. The lead isotope ratios of ²⁰⁴Pb/²⁰⁶Pb, and related element contents (P, Zn, Fe, Mn, Mg, Ca, Cu, Na, K) could be used to identify the effective traceability of organic chickens. The results can provide new identification methods for organic chickens.