2015, 33(3):1-4. DOI: 10.3969/j.issn.2095-6002.2015.03.001
Abstract:Started from food processing, modern food science and food industry have provided the world enormous amount of food and always played a vital role in the development and evolution of human society. To date, food science has systematically studied the food storage, nutrition and sensory characteristics, while the interaction between food and body remains as a puzzle except a few pieces revealed by nutrition science and toxicology. Modern food industry has totally changed the way food is produced and consumed, and more importantly the way food interacts with human body. The ignorance of such changes in food science has made the debates in safety and health risks of industry food even more confusing. Three research topics are proposed for food-body interaction:elucidate the existing status of food compositions; interpret the body response to food; methods to utilise the complementary characteristics of different food compositions. From these new perspectives, some unique approaches and original discoveries of food science ought to be achieved, to provide answers to the major criticism upon food industry and transform food science to an intact science of food, an independent discipline of science.
2015, 33(3):5-8. DOI: 10.3969/j.issn.2095-6002.2015.03.002
Abstract:Tomatoes are known as fruits and vegetables. A growing number of tomato products have been developed in recent years and the innate value of tomato has been greatly increased after the deep processing. Therefore, the quality of tomato products has gained more and more attentions from consumers. This paper described quality control and safety management about tomato breeding, cultivation, harvesting, storage, and sales, and made an evaluation of tomato safety production from the whole industry chain, which provided reasonable basis for the healthy development of the tomato industry.
2015, 33(3):9-12. DOI: 10.3969/j.issn.2095-6002.2015.03.003
Abstract:The quality safety issue of leek, a favorite kind of vegetable in China, was concerned. The factors influencing the quality safety of leek were discussed from pesticide residue, nitrite, and heavy metal aspects. The countermeasures were also proposed to guarantee the quality safety of leek, which were reasonable location,standardization management, ecological prevention and control technology, food safety propaganda, and rigorous inspections and law.
2015, 33(3):13-21. DOI: 10.3969/j.issn.2095-6002.2015.03.004
Abstract:The Typica and Catimor coffee beans in Baoshan, Yunnan province were chosen as the experimental materials to measure the concentrations of main volatile aroma compounds under the different roasting strength. Headspace solid phase microextracion and gas chromatography-mass spectrometry (GC-MS) were applied to analyze the concentrations of pyridine, guaiacol furfuryl alcohol, 2-methylpyrazine, 2,6-dimethylpyrazine, 2-ethyl-3,5-dimethylpyrazine, furfuryl alcohol, 5-methylfurfural, and maltol. According to the result of scanning electron microscope (SEM), the size of micropores in coffee beans increased with roasting strength, improving the release abilities of main aroma compounds.
2015, 33(3):22-27. DOI: 10.3969/j.issn.2095-6002.2015.03.005
Abstract:The organic volatile components in fresh hawthorn were studied using simultaneous distillation extraction and gas chromatography-mass spectrometry (SDE-GC-MS). A total of sixty-one volatile components were identified, including 16 hydrocarbons, 16 alcohols, 10 aldehydes, 9 esters, 4 phenols, 3 ethers, 2 ketones, and 1 acid. These components were determined by MS and conformed by comparison of the retention times of the separated constituents with those of authentic samples and by comparison of retention indexes of separated constituents with the RIs reported in the literature. The predominant volatile component (over 2%) in fresh hawthorn was cis-3-hexenyl acetate (16.08%), followed by furfural (10.97%), α-terpineol (7.02%), 1,4-butanediol (5.92%), hexyl acetate (3.55%), eugenol (3.55%), and 1-methyl-4-(1-methylethenyl)-benzene (2.53%). From the odor characteristics of identified components, it can be known that the ester compounds, alcohol compounds, and aldehyde compounds were the characteristic volatile components of fresh hawthorn.
2015, 33(3):28-34. DOI: 10.3969/j.issn.2095-6002.2015.03.006
Abstract:The enzymatic hydrolysis of laver and preparation technology of seafood flavor were studied using Porphyra yezoensis as raw materials. By comparing the hydrolyzing ability of different enzymes and the flavor of hydrolyzates, the best enzyme was screened. The hydrolysis conditions were optimized through the orthogonal experiments using the degree of hydrolysis and sensory evaluation as the reference standard. The optimum hydrolysis conditions were temperature 55℃, time 3h, and the addition of enzyme 3%. Then the hydrolyzate was used to make seafood flavor by the Maillard reaction. With the sensory evaluation as the reference standard, the optimum formulations and optimum conditions of the Maillard reaction were determined through response surface experiments:glutamate 1mg/mL, glycine 0.5mg/mL, cysteine 0.15mg/mL, xylose 8mg/mL, glucose 4mg/mL, thiamine 0.4mg/mL, the reaction temperature 110℃, pH6, and the time 50min. The product showed fine seafood flavor and the flavor was evident. The amino acid composition analysis showed that glutamate and alanine contents were significantly increased in the hydrolyzate. The amino acids in the Maillard reaction were mainly glycine, glutamic, and cystine. About 41 volatile organic components were detected by GC-MS.
2015, 33(3):35-42. DOI: 10.3969/j.issn.2095-6002.2015.03.007
Abstract:Four protein fractions (albumin, globulin, prolamine and glutelin) were fractionated from peanut meal and their surface structures were observed using scanning electron microscope. The result showed that the optimum extraction condition for albumin was temperature 50℃, extraction time 12min, and the ratio of material to solvent 1∶12. The extraction yield and purity of albumin was 53.59% and 72.14%. The optimum extraction condition of globulin was temperature 50℃, concentration of NaCl is 0.4g/L, and the ratio of material to solvent 1∶10. The extraction yield and purity of globulin were 9.03% and 73.20%. The optimum extraction condition of prolamine was concentration of ethanol 70%, extraction time 12min, and the ratio of material to solvent 1∶6. The extraction yield and purity of prolamine were 8.62% and 64.28%. The optimum extraction condition of glutelin was extraction temperature 45℃, extraction time 15min, pH 8, and the ratio of material to solvent 1∶10. The extraction yield and purity of glutelin were 4.85% and 68.79%. The result of scanning electron microscope showed that the surface of the four protein fractions was different.
2015, 33(3):43-48. DOI: 10.3969/j.issn.2095-6002.2015.03.008
Abstract:Chitosan, sodium alginate, activated carbon,and graphene oxide were selected to immobilizenaringinase. By comparing the activities of immobilized naringinase and the enzyme-carrying rates of the enzyme carriers, it was found that graphene oxide was the optimal material. The enzyme-carrying rate of graphene oxide was 85.61% and theenzyme activity of graphene oxide immobilized naringinase was 410.50U/g. The enzyme activity remained 72.38% relative activity after 7 times using. Simultaneously, the effects of different conditions on catalytic activity of graphene oxide immobilized naringinase were studied. It was obtained that the optimal load amount of naringinase per gram of graphene oxide 60mg, optimal temperature 20℃, optimal pH 4.0, and immobilization adsorption time 9h. The activity of graphene oxide immobilized naringinase reached 433.70U/g under the optimized conditions, which remained 78.62% relativity activity after 7 times using.
2015, 33(3):49-55. DOI: 10.3969/j.issn.2095-6002.2015.03.009
Abstract:The sensory evaluation of imported dry red wines aims at selecting the characteristics that influence the ultimate sensory quality. Well-selling wine samples belonging to the price category of 100-600 ￥ were selected randomly from the imported wine market of Shanghai. The 30 trained panelists of wine-tasting group were asked to quantify the sensory characteristics by five-point scale and then grade the overall sensory quality. The value of each sensory character was the geometrical mean of its frequency and intensity. Principal component analysis (PCA) showed twenty-three sensory characteristics were significantly contributed to sensory quality. And the overall quality could be satisfactorily explained by the partial least square regression (PLSR) model with twelve important characteristics. The results showed that there were characteristics differences among sample wines. The wine overall quality was related with the price positively, and the overall quality could be regressed with some sensory characteristics.
2015, 33(3):56-58. DOI: 10.3969/j.issn.2095-6002.2015.03.010
Abstract:Elements had different chemical and biological effects due to the different forms, which caused different chemical behaviors in the ecological environment and organisms. The study of element forms was important for the ecological environment and human health. This study focused on the application of the elemental speciation analysis method in the agricultural products, seafood, tea, health care products, and so on.
2015, 33(3):59-63, 69. DOI: 10.3969/j.issn.2095-6002.2015.03.011
Abstract:The tocopherol contents in 8 kinds of edible vegetable oils (total 24 samples) were determined by HPLC and the extraction conditions were optimized. Tocopherol was extracted three times by the ultrasonic method and the extraction conditions were liquid material ratio 1∶1.25 and extraction time 20min. The results showed that the correlation coefficient R2 was 0.9992-0.9994 within the scope of 0.05-1.00g/L. The detection limits of α-tocopherol, γ-tocopherol, and δ-tocopherol were 0.5,2.0,1.2mg/L, respectively, and the recovery average was 92.1%-99.8%. Meanwhile, the relative standard deviation (RSD, n=3) was between 2.5%-8.5%. Sunflower seed oil had the highest α-tocopherol content (4.2349×10-4) while soybean oil had the highest β/γ-tocopherol (7.3713×10-4), δ-tocopherol (1.6215×10-4), and total tocopherols (9.8836×10-4) contents.
2015, 33(3):64-69. DOI: 10.3969/j.issn.2095-6002.2015.03.012
Abstract:To determine the efficacy of chitosan, sodium alginate, and konjac glucanmannan on the shelf-life and overall quality of strawberry fruits, we repeatedly estimated the weight loss, decay percentage, sensory evaluation, hardness, soluble solid content (TSS), ascorbic acid content, titratable acid (TA) content, and antioxidant activity of strawberry fruits coated with these three polysaccharides during the storage period. Results demonstrated that chitosan, sodium alginate, and konjac glucanmannan could significantly delay the main changes of strawberry fruits. Among the three polysaccharides, chitosan was especially useful for extending the shelf-life and maintaing quality of strawberry fruits, and konjac glucanmannan was best for the maintenance of the TA content.
2015, 33(3):70-73, 78. DOI: 10.3969/j.issn.2095-6002.2015.03.013
Abstract:The research introduced the process of a kind of compound beverage using the materials of ginger extract, red jujube, and brown sugar. The optimum formula was obtained by the orthogonal test with sensory evaluation as the index, which was ginger extract 0.06%, jujube juice concentrate 0.4%, brown sugar 3.0%, and sugar 4.0%. Meanwhile, the stability of the compound beverage was studied. The results showed that the composite stabilizer including 0.1% CMC-Na and 0.05% gelatin had the best effects.
2015, 33(3):74-78. DOI: 10.3969/j.issn.2095-6002.2015.03.014
Abstract:In order to detect the problems of food safety in time and reduce the incidence, a food safety supervision of real-time analysis and prediction model based on the storm cloud platform and the Elman neural network optimizing by the bat algorithm was constructed from the perspective of food supply chain. Through analyzing the factors affecting food safety, the model was used to analysis the food safety data in real-time. By the analysis of the model, an effective food safety supervision mechanism in real time was formed to further reduce the food safety hazards.