Advanced Materials Research Vols. 1033-1034

Abstract: During cold preservation, the pH and moisture of beef decreased slowly. Changes in ash and protein content had no obvious rules, but the data analysis results showed that the effect of drugs on these indexes was significant. Ca, Fe content decreased, Zn content increased, TBARS values were significantly higher than those in the blank , and violent fluctuation. SAR and DIF had obvious bacteriostasis effect. Cold preservation had no palpable effect on fluoroquinolones residues.

Abstract: Changes in physical, chemical, microbiological and sensory qualities of cooked crayfish (Procambarus clarkia) meat, treated at different freezing rate (-30°C,CPF; -60°C,ULTF; -196°C,LNM), were investigated during storage at -20°C for up to 6 months. pH value increased in all treatments with the sharp reduction after 3 months. Increase in weight loss of LNM was slower than that of CPF and ULTF cooked crayfish. During frozen storage, thiobarbituric acid value (TBA value) fluctuated in all treatments, but lipid oxidation did not affect the quality of crayfish meat because of its lower fat contents. Total volatile basic nitrogen (TVB-N) increased with storage time, with the reduction of TVC and sensory score. Freezing rates could not cause significant changes in chemical qualities (pH value, total volatile basic nitrogen, thiobarbituric acid value), sensory quality and microbiological quality for all three treatments during storage. In spite of decrease of quality of cooked crayfish meat in all treatments, good edibility was kept throughout the storage.

Abstract: The flesh firmness of AC and rin mutant tomato fruits picked freshly were the largest. Respiration rate and ethylene production were very low at this time. With ethylene production increase, fruit firmness began to decline. 100μL/L ethephon significantly increased AC tomato fruit ethylene release, respiration rate, ACS activity and ACO activity, and decreased flesh firmness. However, there were no significant differences in rin mutant between control and ethephon treatment. It was shown RIN transcription factor regulated ethylene biosynthesis by ACC synthase and ACC oxidase.

Abstract: The moisture sorption characteristics of salted largehead hairtail (Trichiurus lepturus) were investigated within the limits of water activity (0.11-0.98) at 25 and 35°C using a self-made instrument for the measurement of the equilibrium moisture content according to the static gravimetric method. The shape of the sorption isotherms was sigmoidal. The moisture sorption isotherms exhibited significant hysteresis. The hysteresis of salted fish may be due to the salt permeating into the body of the fish as a result of desorption and adsorption processes. Seventeen mathematical models were fit to the experimental data for the equilibrium moisture content at different water activity levels. The Ferro-Fontan equation provided the best fit for the experimental data of the equilibrium moisture content among the 17 models assessed for the sorption isotherms at 25 and 35°C. The net isosteric heats of sorption decreased gradually with increases in moisture content. The isosteric heats of sorption ranged from 44.59 kJ/mol to 45.61 kJ/mol between the moisture contents of 22.22% and 43.25% for salted largehead hairtail.

Abstract: Non-enzymatic browning often occurs in the processing of chestnut kernel.Chemical components of chestnut kernel that related to the browning have been studied in this paper in order to control the browning. Results were showed as followed: after the non-enzymatic browning in processing,the protein content of the cooked chestnut kernel decreased by 30.34%, reduced sugar content decreases by 38.44% and ascorbic acid content decreases by 85.81%. Therefore, Maillard reaction and ascorbic acid oxidation were the main reactions resulting in the browning of cooked chestnut kernel. In addition, the influence of pH is significant while sucrose and sodium chlorine had no effects on the non-enzymatic browning. Solution with pH of 3,4,or 5 displayed rather good effects on inhibiting the browning of cooked chestnut kernel.

Abstract: The influences of 1-MCP on AC tomato fruit softening were investigated. Ethylene production, flesh firmness, protopectin content, soluble pectin content and polygalacturonase (PG) activity were used to evaluate the quality of tomato fruit. It was shown that 1.0 and 1.5 μL/L 1-MCP treatment significantly decreased the levels of ethylene production, and inhibited flesh firmness and protopectin content decline and polygalacturonase activity increase. At last, it was concluded 1.0 μL/L 1-MCP treatment on AC tomato fruit was the best determining economy.

Abstract: This study evaluated the nutritional characteristics and percentage of released nitrogen (%) of silkworm pupae proteins and peptides after simulated gastric and intestinal digestion, with a view to use in animal feeds or human nutritional support. Distribution of molecular mass and amino acids in the processed protein were analysed and the amino acid score, chemical score, and essential amino acid index (EAAI) calculated. Differential scanning calorimetry and simulated in vitro gastrointestinal digestion were used to analyse the denaturation temperature and absorption characteristics of samples. The denaturation temperatures suggested that silkworm pupae proteins and peptides were stable at room temperature. Silkworm pupae proteins and peptides contained all amino acids required by humans, and the composition was reasonable. Simulated gastrointestinal digestion resulted in about 90% nitrogen release amount. All data indicate that this protein may be useful as an economic, high quality supplement in animal feeds and for human nutritional support.

Abstract: The effects of maltodextrin concentration,inlet air temperature and outlet air temperature on the anthocyanins extraction from blueberry pomace by spray-drying technology were studied by response surface methodology. Based on single factor experiment, the quadratic regression model of the powder yield and loss rate of anthocyanins were deduced, then variables were analyzed with response surface methodology (RSM) by Box - Benhnken experiment. Results showed that the optimal technological conditions for spray drying the anthocyanins extraction from blueberry pomace were obtained as follows: maltodextrin concentration was 25.15% , inlet air temperature was 183.03°Cand outlet air temperature was 60.00°C.

Abstract: Using ultrasonic-extraction technology, the condition of extracting the active compounds-flavonoids and rosmarinic acid of Perilla was studied. The effects of four main factors include ultrasonic power, temperature, time and solid-liquid ratio on the extraction-rate of the flavonoids and the rosmarinic acid of Perilla were reviewed by single factor experiments,and the flavonoids and the rosmarinic acid was determined by NaNO₂-Al (NO₃)₃-NaOH method and FeSO₄ method. On the base of single factor experiments, the extraction technique was optimized in the orthogonal test. The result showed that temperature was the most important factor in the influencing factors on the extraction-rate. The subsequence of importance was temperature > time > solid-liquid ratio > ultrasonic. The optimal extraction conditions were: extraction solvent 3%borax, solid-liquid ratio 1:50(w/v), ultrasonic power 300W, time 90min , temperature 75°C. Under the optimum technological conditions, 34.64mg/g of flavonoids and rosmarinic acid from Perilla could be obtained.

Abstract: Subcritical 1, 1, 1, 2-tetrafluoroethane (R134a) extraction was applied to remove cholesterol from spray-dried Sthenoteuthis oualaniensis egg powder. Response surface methodology (RSM) was applied to optimize the parameters of subcritical R134a extraction (pressure, temperature, and extraction time) on removal rate of cholesterol. Response surface analysis showed that the data came to a precise fitting to a second-order polynomial model. The quadratic terms of pressure and temperature had high significant negative effects (p＜0.001) on removal rate. The optimum parameters of the variables were 8.6 MPa, 55.4 °C, 50 min. Under these conditions, removal rate of cholesterol was predicted to be 101% and experiments gave out the removal rate of 99.16%, which concurred with the model prediction. Furthermore, the removal efficiency of cholesterol by R134a was higher than those achieved by using supercritical carbon dioxide(SC-CO₂)and β-cyclodextrin extraction methods.