The Properties Of Salt Soluble Proteins Of Oratosquilla Oratoria

Oratosquilla oratoria is widely distributed,its meat is tender, rich nutrition and popular with consumers.Based on the oratosquilla oratoria salt-soluble protein as the research object,firstly the study optimized the extraction condition for the oratosquilla oratoria salt-soluble protein, the oratosquilla oratoria salt soluble protein extraction process;Second conditions for the oratosquilla oratoria salt-soluble protein of phosphorylation was optimized, and the emulsifying properties and foaming properties of oratosquilla oratoria salt soluble protein after phosphorylation were studied; and then the hydroxyl free radical oxidation system induced structure and function changes of the oratosquilla oratoria salt-soluble protein were studied; finally,effects of different treatment conditions on the reducing power and the scavenging O2- free radical activity of salt-soluble protein from oratosquilla oratoria.This research provides basis for comprehensive utilization of oratosquilla oratoria and controlling protein oxidation in the processing of oratosquilla oratoria. The main research results as follows:1、To optimize the fast extraction condition for the oratosquilla oratoria salt-soluble protein, the best assisted extraction methods was obtained on the basis of single-factor investigation. Results show that the magnetic stirring time,extraction solution concentration of NaCl and material-liquid ratio had significant influence on protein content(p < 0.05).Extraction solution pH value on the protein content was not significant(p > 0.05).The optimize extraction condition was as follow : extraction solution pH of 6.36, extraction solution concentration of NaCl was 0.11 mol/L, material to water ratio at 1∶3, and magnetic stirring extraction-duration of 24 min. The salt-soluble protein content could reach 22.46 mg/g, and the theory predicted value(22.71 mg/g)differs by 0.25 mg/g.2、The oratosquilla oratoria salt-soluble proteins were phosphorylated with sodium tripoly phosphate(STP) to improve the functional properties of the salt-soluble protein. On the basis of single-factor investigation, response surface methodology was employed to establish optimum conditions for the oratosquilla oratoria salt-soluble protein of phosphorylation. Results show that reaction pH value, STP use level, reaction temperature and reaction time had significant influence on the degree of phosphorylation(p < 0.05).The best conditions of phosphorylation was 4% of STP, pH8.5, reaction temperature of 30℃and reaction time of 2.5h The degrees of phosphorylation could reach 4.715μg/mg, the relative error value is 0.15% with the theory prediction value. Compared with not phosphorylation proteins,the emulsifying activity, emulsion stability, foaming properties,foam stability of the oratosquilla oratoria salt-soluble proteins increased by 61.90% 、23.99%、23.99%、61.90% respectively.3、The objective of this study was to investigate the content of carbonyl, sulfhydryl,bityrosine and the surface hydrophobicity, the turbidity, emulsifying of the oratosquilla oratoria salt-soluble protein treated by hydroxyl radical generating systems containing 0.1mmol/L ferric trichloride, 0.1 mmol/L ascorbic acid and 0~20 mmol/L hydrogen peroxide for 1, 3 h and 5 h respectively. The results revealed that the carbonyl content, the bityrosine content, the turbidity and the sulfhydryl increased, while sulfhydryl content, emulsifying activity and emulsion stability decreased. These oxidation-induced structural changes reveal high susceptibility of the oratosquilla oratoria salt-soluble protein to oxidative stress.4、The reducing power and the scavenging superoxide anion free radical activity of salt-soluble protein from oratosquilla oratoria was selected as the index to investigate the effects of heat treatment, solution pH value, food ingredient and metal ions on the antioxidant activity of salt-soluble protein. The results showed that low temperature treatment and the alkali environment were beneficial for increasing the reducing power and the scavenging superoxide anion free radical activity of salt-soluble protein from; to a certain extent, food ingredient and metal ions could reduce the reducing power and the scavenging superoxide anion free radical activity of salt-soluble protein from. The addition of citric acid had considerable impact on the scavenging superoxide anion free radical activity of salt-soluble protein from in the food ingredient; the scavenging superoxide anion free radical activity from remained at a stable level in the presence of Mg2+, but the addition of Zn2+ could reduce the scavenging superoxide anion free radical activity from obviously in medal ions.