2016, 34(1):1-8. DOI: 10.3969/j.issn.2095-6002.2016.01.001
Abstract:Aquatic product freshness evaluation standards were reviewed in this paper, including the traditional freshness evaluation methods and some kinds of new methods in recent years. Meanwhile, shelf-life predicting models of aquatic products were also introduced, including primary shelf-life model, secondary shelf-life model and tertiary shelf-life model. Moreover, the main problems and the research tendency of freshness comprehensive evaluation and establishment of shelf-life model of aquatic products were discussed, aiming to provide the convenience for the future research of aquatic products.
2016, 34(1):9-15. DOI: 10.3969/j.issn.2095-6002.2016.01.002
Abstract:Pasteurized milk is internationally recognized dairy products with fresh flavor and nutrition. In USA, Europe, and other developed countries, pasteurized milk has more than 90% market share of fluid milk products. In China, pasteurized milk has rapidly developed in recent years and has more than 25% annual growth rate.It would become leading dairy products for city consume and new economic growth point of dairy industry in future. In this paper, we review the requirements of pasteurized milk for raw milk, pasteurization processing technology, shelf life, main spoilage microorganism and detection, identification, and the application of microfiltration technology to improve quality and shelf life.
2016, 34(1):16-20. DOI: 10.3969/j.issn.2095-6002.2016.01.003
Abstract:The status of quality and safety issues of fermented dairy products in China was summarized, of which hazard sources were analyzed based on the quality of raw materials, contamination of common microbes and phages, as well as migration of packing materials. Besides, the targeted solutions were proposed correspondingly, while the research interests were further prospected in the safety of fermented dairy products, in order to provide an advisable reference for better quality of fermented dairy products.
2016, 34(1):21-27. DOI: 10.3969/j.issn.2095-6002.2016.01.004
Abstract:Supervised principal component analysis was used to establish the evaluation model of oil-used peanut. K-means cluster analysis was applied to analysis the processing suitability of oil-used peanut. The results showed that the evaluation model of oil-used peanut included the crude fat content, ratio of oleic acid and linoleic acid, and unsaturated fatty acid content. The correlation coefficient between the predicted value and measured value was 0.70. The evaluation model could classify the peanut varieties into three scales and yuanza 9102, luhua 9, xuhua 14, heihuasheng, and haihua 1 were mostly suitable for peanut oil processing. The results are very important to predict the suitability of any unknown varieties.
2016, 34(1):28-36. DOI: 10.3969/j.issn.2095-6002.2016.01.005
Abstract:China is one of the world’s largest countries in potato production and consumption. Cultivar differences have significant effects on the quality and yield of potato products. In order to choose proper potato materials for optimal products’ processing and provide guiding significance for potato processing industry, 8 main quality indicators were tested based on 44 common potato cultivars in domestic. Statistics analysis showed that, there were obvious differences in indicators of different potato cultivars, and the significant correlation was found between most indicators. To reduce the redundancy, principal component analysis (PCA) was used to transform 8 original indicators into 3 irrelevant principal components. The first principal component was represented as the moisture factor. The second principal component was represented as the sugar factor. And the third component was represented as the protein factor. The cumulative percent of 3 principal components reached 75.77% and could effectively reflect the information of the original indicators. Based on PCA scores for 44 potato cultivars, usages of processing or fresh-eating for different cultivars were suggested. Hierarchical clustering with the Ward method was used to divide 44 potato cultivars into 4 categories and the characteristics of each category were analyzed. The result was accordant with PCA scores, and can provide references and uses for different potato cultivars.
2016, 34(1):37-41. DOI: 10.3969/j.issn.2095-6002.2016.01.006
Abstract:The study investigated the characteristics of Xinjiang main green raisin varieties Thompson seedless and Centennial seedless. The total sugar content, total acid content, and aroma components of raisins were determined by the physical and chemical method and GC/MS technology. The results showed that the sensory quality of two kinds of green raisins had differences while there were not differences in nutritional quality between two kinds of green raisins. Aroma substance were obtained in two kinds of green raisins. Centennial seedless raisin and Thompson seedless raisin had 54 and 50 kinds of aroma components, respectively.
2016, 34(1):42-49, 78. DOI: 10.3969/j.issn.2095-6002.2016.01.007
Abstract:The fermentation conditions for producing exopolysaccharides by Lactobacillus plantarum YW11 isolated from Tibetan Kefir were optimized. The experiment factors and levels were firstly selected by the single-factor test. And then, the influences of significant factors were evaluated using a fractional factorial design. Using the yield of exopolysaccharides as the optimization index, a quadratic polynomial regression equation forecasting model was set up by designing a Box-Behnken design involving of three factors and three levels and the method of response surface analysis,thus the optimized extraction conditions were obtained. The optimized results by the single factor test showed that:fermentation time 18 h, carbon source of lactose (15g/L), nitrogen source of soy peptone (15g/L), fermentation temperature of 32℃, inoculation rate of 3% and pH of 6.0. The significant factors at the analysis range were:soy peptone, pH and inoculation rate ,and the fermentation conditions optimized by response surface analysis were as follows:soy peptone concentration of 13.50g/L, inoculation rate of 2.70%, and pH of 6.27.The exopoly saccharides yield under the optimal condition was 131.26mg/L, near the theoretical value (129.915mg/L).
2016, 34(1):50-54. DOI: 10.3969/j.issn.2095-6002.2016.01.008
Abstract:The extraction, separation and purification of non-extractable polyphenols (NEPP) in blueberries were studied and its components were analyzed using HPLC.The results showed that adsorption and desorption rates of HPD-100C were relatively high among seven kinds of macroporous resins. HPD-100C was used for dynamic purification and HPLC was applied for components analysis. The main components of NEPP were delphinidin, cyanidin, petunidin, peonidin, and malvidin, which is similar to those of extractable polyphenols (EPP).
2016, 34(1):55-65. DOI: 10.3969/j.issn.2095-6002.2016.01.009
Abstract:The volatile compounds of Gujinggong liquor were analyzed by liquid-liquid extraction coupled with GC-MS and identified by comparison with authentic standards, NIST 11 library and retention index. Different compounds were extracted by using different organic solvents with various polarities. Compared with diethyl ether and dichloromethane, n-pentane showed better extraction effect for aromatic compounds; alkanes and sulfur-containing compounds, and dichloromethane showed better extraction effect for heterocyclic compounds. A total of 188 volatile compounds were determined in Gujinggong liquor, including 74 esters, 26 alcohols, 25 aromatic compounds, 20 acids, 14 alkanes, 8 aldehydes and ketones, 8 sulfur-containing compounds, 7 acetals,4 heterocyclic compounds, and 2 lactone compounds. About 167 compounds of them were identified by pure standard.
2016, 34(1):66-71. DOI: 10.3969/j.issn.2095-6002.2016.01.010
Abstract:A graphene-chitosan modified glassy carbon electrode was prepared. Electrical conductivity of the modified glassy carbon electrode (GCE) was investigated by cyclic voltammetry (CV). Competitiveelectrochemical immunoassay was performed to detect diethylstilbestrol by differential pulse voltammetry (DPV). Under the optimized conditions, the Δ-value of oxidation peak current was proportional to diethylstilbestrol concentration in the range between 1 and 2500μg/L. The linear equation was ΔI=25.0368+0.00342ρ (R=0.99124), and the detection limit was 0.1μg/L. A good recovery of diethylstilbestrol in the range of 93.2%-106.8% was obtained in pork, beef, duck, and milk powder.
2016, 34(1):72-78. DOI: 10.3969/j.issn.2095-6002.2016.01.011
Abstract:In this paper, the civil liability system about food safety is researched based on the revised “Food Safety Law”.Revised “Food Safety Law” reflects the country's determination to punish illegal acts of food, and unremitting efforts to create a good environment of food safety.The new “Food Safety Law” strengthens the administrative supervision of food safety, which can help the government to better control all aspects of food production and operation.At the same time, the administrative liability and criminal liability are closer, which will have more deterrent forces for food business criminals. For Chinese food safety problems, much more attentions are paid on executive not civil and the role of civil liability has not been given enough attentions. We should realize the necessity of reconstruction of the food safety civil liability system. From the respect of revised “Food Safety Law”, problems in our existing civil liability system are surveyed. We suggest that civil liability should be added in “Food Safety Law” and the fault-presuming principle should be applied. Meanwhile, the detailed rules of public litigation should be definite.