| Cooking lead to enzyme inactivation, pathogenic bacteria, bacteria and parasites commonly death for mutton, but its it is beneficial to the growth of microorganisms for rich nutrition and easy deterioration during storage. Therefore, people use various methods to prevent deterioration, such as sterilization, low temperature preservation, isolated from the air, drying, use of preservatives, etc. With the improvement of living standards, consumers not only demand of food nutrition and health, also calls for flavor, taste, color, texture, etc. So this thesis research how can you keep cooked mutton products to keep the original flavor and taste, but also can prolong the shelf life. The research methods and conclusions are as follows:(1) By single factor experiment, we research the effects of sterilization time on microwave sterilization, the effects of pressure duration on ultra-high pressure sterilization, the effects of sterilization temperature on pasteurization. We optimize the sterilization conditions are as follows: microwave sterilization (40s/3times/interval of10s), ultra-high pressure sterilization (600MPa/20min), pasteurization (90℃/30min/rapid cooling).(2) We measured some index of the cooked mutton during storage (Oweek,2weeks,4weeks), such as pH, total number of colonies, TVB-N, TBA, red value, hardness, elasticity, glue viscosity and chewiness after sterilization with different sterilization methods. We studied quality change in storage of cooked mutton through the factor analysis method,, and concluded the best sterilization method is microwave sterilization.(3) We analyze the colony of vacuum packaging cooked mutton in storage through a series of experiment and identified the types of microorganisms according to Brown, MH (1982) recommended. We draw the conclusion:lactic acid bacteria, brochothrix thermosphacta, enterobacteriaceae, pseudomonas bacteria were the major colony in storage (20℃); Lactic acid bacteria were dominant bacteria.(4) We explored the effects of compound preservatives for cooked mutton through three factors quadratic orthogonal rotation combination design of experiment. Results show that the optimal compound preservative recipe were0.2819%Nisin,0.1647%ε-poly lysine,2.925%sodium lactate; Single factor effect order as:Nisin>sodium lactate>ε-poly lysine; there is interaction effect between Nisin and ε-poly rysine,ε-poly lysine and sodium lactate。... |
