Tea Polyphenols For Frozen Freshwater Fish Biochemical And Functional Characteristics Of Impact Study

As a favored high-protein goods, the nutritional value of freshwater fish is very rich, containing eight essential amino acids, unsaturated fatty acids, especially DHA and EPA, it is important for human health. As a big country of the world’s fisheries, freshwater fish production has been ranked first in recent years. The freshwater fish products exports of our country has shown increasing, the freshwater aquaculture development space will be more broad. According to statistics, nearly10years our country’s freshwater aquaculture average annual growth rate of more than25%, in2008, China’s freshwater aquaculture products output reached48.96million tons, is nearly10times in1978, accounting for70.89%of the total output of aquatic products. Studies have shown that tea polyphenols have anti-cancer, antioxidant, antibacterial, prevention and treatment of cardiovascular disease, and improve the comprehensive immune ability, radiation protection, prevent tooth decay and other health functions. Based on grass carp as the research object, this paper adopts the food chemistry and instrumental analysis methods to study the effect of tea polyphenols on freshwater fish protein, discusses the application prospect of tea polyphenols in freshwater fish fresh. Research methods and results are as follows:(1) Tea polyphenols on the frozen freshwater fish peotein biochemistry charateristics were studied systematically for the first time. The changes were measured by the salt soluble protein extraction, ATPase activity measurement, SDS-page gel electrophoresis, and ultrastructure observation of grass carp fish treated with different concentrations of tea polyphenols and stored at-18℃. The result showed:the salt soluble protein extraction performance and ATP enzyme activity has decreased with the time, these declines were retarded substantially by adding tea polyphenols; the SDS-page results showed that the protein degradation rate was decelerated by adding tea polyphenols, and showed a certain dose relationship; The changes of muscle protein structure by electron microscopy confirmed the above observations, these results showed that biochemical characteristics of the protein has a protective effect by adding tea polyphenols in the grass carp fish, and the optimal concentration was about0.05%～0.07%.(2) Tea polyphenols on the frozen freshwater fish peotein functional propertices were studied systematically for the first time. The protein emulsification, gel property, rheological property of grass carp fish treated with different concentrations of tea polyphenols and stored at-18℃was studied by using visible spectrophotometer, texture analyzer, rheometer. The results showed that the addition of more than0.03%of tea polyphenols can slow down the grass carp protein emulsification ability and emulsion stability,.The higher the concentration, the better the results; The storage and loss modulus G’and G" were the lowest when the tea polyphenols content was0.03%suggesting that the extent of crosslink of proteins was the lowest. The tea polyphenols can improve protein emulsification and gel property.