Advanced Materials Research Vols. 781-784

Abstract: The rheological properties of κ-Carrageenan-Konjac Gum Mixed Gel were investigated by using dynamic rheological analysis. Results showed that the mixture of κ-Carrageenan and Konjac Gum had higher modulus of elasticity than single κ-Carrageenan or Konjac Gum. Blends solution has a good pseudo-plastic behavior at low concentrations, viscosity declined rapidly with shear rate increased. K⁺ and Ca²⁺ participated in the gelatin process and under the controlled condition might enhance force among molecules. With the temperature increasing G' and G" increased, and G' and G" presented suddenly change at 60-70 °C. Small amplitude oscillatory tests in the linear domain of viscoelasticity showed that κ-Carrageenan played the major role in the viscoelasticity of the mixture, and Konjac gum strengthened the gel-net configuration and stability.

Abstract: Two strains with nitrite degradation ability were obtained from Kimchi. According to morphology, Gram-stain, physiological tests, the isolates were identified primarily as Lactobacillus brevis and Lactobacillus plantarum, respectively. Comparing the nitrite degradation rate of two strains, the strain L. plantarum Z1 with higher degradation rate was utilized to investigate effects on sodium nitrite degradation (NaNO₂) during pickle fermentation. The strain L. plantarum Z1 was inoculated to 200mL MRS medium including 120μg/mL NaNO₂ with inoculum of 1% after culturing at 30°C for 18 h. Several experiments that involved different temperature, pH, substrate concentration were carried out. Nitrite degradation ability of L. plantarum Z1was estimated from detection of the residue concentration of NaNO₂. The optimal conditions for nitrite degradation were: growing temperature at 30°C, initial pH at 5.5 and substrate concentration of 400μg/mL. Under these conditions, the nitrite degradation efficiency was up to 96% with residue of 4.8μg/mL which is below the content of National Standards. The ability to degrade sodium nitrite provided a tool for LAB (Lactic acid bacteria) application to improve their industrial performance.

Abstract: This study aims to investigate the Chongqing office workers cognition on food safety when eating out, then to provide basic reference about the food safety education for the office workers. A questionnaire survey was conducted among 2637 office workers in eight commercial centers of Chongqing municipal main urban districts by street interview, using self-designed questionnaire of Chongqing main urban office workers cognition on food safety when eating out. 2400 valid questionnaires were analyzed. 64.41%(1540/2391) of the office workers would pay attention to food safety problem. 14.73% (352/2390) of the office workers were aware of food safety grade rating, and the awareness rates of male are significant higher than female. When meeting with food safety problems, 80.87% (1936/2394) of the office workers would choose to exchange the dishes, 30.95% (741/2394) of them would remind friends not to consume, 23.73% (568/2394) of them would refuse to pay for the dishes, 10.74% (257/2394) of the office workers would claim for compensation, 9.36% (224/2394) of them would report it to the department concerned, 9.19% (220/2394) of them thought they had bad luck,2.92% (70/2394) of the office workers would choose to disclose it by media. The main channels of food safety information were TV (85.54%, 2087/2385), newspapers (68.60%, 1636/2385), network (55.89%, 1333/2385), and magazines (24.70%, 589/2385). The attention that office workers paid to food safety and the relevant laws, regulations and measures is low, and the office workers lack of right-protection awareness, Besides TV and newspapers, network has become the main sources of information on food safety.

Abstract: Experiment was studied on water soluble compounds of grass carp (dorsal meat) with different heat treatment. The result showed that different heat treatment can cause the difference of water soluble compounds. IMP is one of degradation products of ATP, the content would increase with ATP degradation in a certain period. K value of fresh sample was 1.83%, it had no obvious difference after in the refrigerator of-20°C for 48 hours, but it increased compared with fresh sample when heated and reheated. In the dorsal meat, the contents of glycine (Gly) alanine (Ala) and histidine (His) were higher than others. The contents of total free amino acids (TFAA) contents reached maximum when reheated for fresh sample. The contents of TFAA in grass carp had no obvious regularity changes with different heat treatment.

Abstract: The effect of mixture material with different levels which consisted in soybean residue, soy protein isolate and wheat gluten(0/65/35%-60/5/35%) during high-moisture extrusion, using a laboratory size co-rotating, twin screw food extruder under 50%-60% feed moisture content and 130-150 °C cooking temperature on selected extruder responses, color and textural properties of extruded products was studied. The results show that soybean residue content and feed moisture is negative correlation (r=-0.666 and -0.601) with the hardness of fibrous meat analogs. But cooking temperature has not significant correlation (P>0.05) with the changes of extruder response, color or textural properties of meat analogs.

Abstract: The microbiological characters and composition of bacterial flora in fresh turbot Scophthalmus maximus were observed with qualitative and quantitative analysis. Samples of turbot fish were collected in the spring, summer and autumn of one year. The total amounts of bacteria from the culturing water, gills and skin were quantified as 3.46±2.4-3.82±1.2 log₁₀cfu·ml^-1, 5.19±2.3-6.28±1.7 log₁₀cfu·ml^-1 and 2.70±1.1-2.95±2.8 log₁₀cfu·ml^-1, respectively. The isolated strains and bacterial flora were identified and classified. The results showed that among 206 isolated strains, Gram-positive bacteria accounted for 18.9% of the total flora, and Gram-negative bacteria formed 82.4%, including predominant bacteria such as Staphylococcus aureus (12.6%), Serratia liquefaciens (10.7%), Enterobacter (19.4%) and Pseudomonas (8.3%). A large number of isolated Enterobacter indicated that the culturing water was polluted. We report here for the first time the microbial flora in the turbot cultured in deep well seawater of Liaodong Penisula, which provides a preliminary basis for the subsequent study on the specific spoilage organisms from chilled turbot fish.

Abstract: Cholesterol-lowering effect of lactic acid bacteria is well-known. In this study, nine cholesterol-lowering Lactobacillus strains from Chinese traditional cheese, pickle and yoghurt were screened and characterized for their potential use. The microbial content of all the strains was significantly decreased at pH 1.5, but the residual counts of L. casei subsp. casei GL-03, L. plantarum ZP-Z, L. plantarum ZP-05 and L. brevis ZP-04 were more than 107cfu/mL after 6h of incubation. All the nine strains of Lactobacillus indicated good tolerance to bile at concentration less than 0.2% after 2 or 6 h of incubation. L. plantarum ZP-W had maximum hydrophobicity towards xylene while GL-03 strain possessed maximum hydrophobicity for both hexadecane and octane. ZP-05 strain had more effective inhibitory activity against Escherichia coli, Staphylococcus aureus, Bacillus subtilis and Shigella dysenteriae than other eight strains. These results suggest that L. casei subsp. casei GL-03 may be effective as a probiotic with cholesterol-lowing activities.

Abstract: Virus-induced gene silencing (VIGS) is a powerful tool for the study of gene function and down regulate specific gene expression in plant. The RIN transcription factor is an important developmental regulator in tomato fruit ripening. In this work, the TRV-LeRIN infiltrated fruit significantly developed green color phenotypes, whereas the control fruit would turn red normally. Dissection of silenced areas for analysis identified whether the LeRIN gene is silenced or not. Taken together, we successfully applied syringe infiltration method of VIGS to silence the LeRIN gene in tomato fruit. These results are critical for understanding the mechanism of tomato fruit ripening.

Abstract: The antioxidant activity of Polyrhachis vicina wine extract was investigated: The IC₅₀ of scavenging effect on superoxide radical generated by Pyrogallol autoxidation was 0.37 mg/mL; the maximum scavenging rate was 81.4%. The IC₅₀ of scavenging effect on hydroxyl free radical generated by Fenton reaction was 0.66 mg/mL; the maximum scavenging rate was 91.8%. The IC₅₀ of DPPH· scavenging effect was 0.48 mg/mL; the maximum scavenging rate was 91.4%. The results indicated that Polyrhachis vicina wine extract showed activity both in scavenging free radicals and antioxidation.

Abstract: To prepare an immuno-affinity column (IAC) for Sudan I, Sepharose 4FF was activated by epichlorohydrin, and the density of epoxy is 80 μmol/g. Then it was coupled with 6-aminocaproic acid. The Sudan I immunoaffinity column was prepared by carbodiimide method in which modified Sepharose 4FF was used as carrier to couple with monoclonal antibody against Sudan I. A reversed-phase high performance liquid chromatographic method was used to determine the samples elution after the IAC cleaning up. Sudan I was determined by HPLC with a retention time of 5.82 min (flow rate of 1 ml/min). The column capacity is 1582.8 ng Sudan I when using 0.3 g Sepharose 4FF. Average recoveries of Sudan I from red chili powder spiked at levels of 0.25-3 mg/kg range from 44.52% to 77.40%. The coefficient of variation is 4.6% to 8.3%. The IAC method was found to be highly effective, sensitive and convenient for isolating the target analyte from sample.