The Research And Application Of Biological Preservatives In Pseudosciaena Crocea

The paper analysed the bacterial phase and dominated spoilage bacteria at the end of shelf life of Pseudosciaena crocea , studied the antibacterial ability of tea polyphenols,chitosan,ε–PL,Nisin, citric acid,the extraction of clove and cinnamon.The optimum combinations of the several preservatives were researched by using the response surface methodology.The effects of the optimum combination of the preservatives for the preservation of Pseudosciaena crocea were also researched,the results included several parts as follows:1. 126 strains microorganisms of Pseudosciaena were isolated and preliminary identified. Including 68 strains Shewanella putrefacens, 27 strains Pseudomonas, 9 strains Flavobacterium,7 strains Alcaligenes and 15 strains unidentified. Shewanella putrefacens and Pseudomonas is dominated spoilage bacterial, of each accounted 54.0% and 21.4%.2. The result of the experiment of minimum inhibitory concentration and filter paper discagar diffusion showed that tea polyphenols,chitosan,ε–PL,nisin,citric acid,the extraction of clove and cinnamon showed the different degrees of antibacterial ability.The growth of spoilage bacteria could be effectively inhibited by tea polyphenols,chitosan,ε–PL and citric acid,the extraction of clove and cinnamon taked second place, while nisin couldnot inhibite the growth of spoilage bacteria.3. The species and concentration of preservatives were determined by single factor experiments.The optimization of the combination of the preservatives was focused on the preservation of fish by Response surface methodology.Quadratic polynomial equation was obtained through multiple regression analysis.The predicted model was proved adequate when tested by the lack of fit and coefficient of determination.There was a significant synergy between chitosan and citric acid (P<0.01).The results of regression analysis showed that the optimum proportion of the combination of tea polyphenols,chitosan and citric acid was 4.48g/L,15.92g/L and 3.58g/L.4. The effects of the optimum combination of the three preservatives for the preservation of Pseudosciaena crocea were evaluated with microbial qualities,physical and chemical qualities and sensory qualities. The fish stored at 4℃and treated using the compound preservative was 13 days respectively,while the contrast could preserve 6 days.