Excellent Kimchi Fermentation Agent Screening And Preliminary Study

Pickle is a traditional vegetable production with lactic acid fermention, which has a long history. For pickle has unique and delicious flavor and a lot of nutrition effection, people enjoy it very much all over the time. The objective of this thesis was to select the superior strains,so as to improve the quality of domestic pickle.In this research,six strains were isolated from many sorts of pickles for the superior characteristics in acid production ,degradation of nitrite and fermentation flavor. With the morphologic character, physiological and biochemical experiment and sugar fermentation , strain 6 and strain 25 were identified as Lactobacillus brevis; strain 9 was Lactobacillus minor; strains 17,19 and 22 were identified as Leuconostoc gelidum. The growths of strains 17,19 and 22 were restianed at the condition at which the pH was lower than 3.0 or the salty concentration was higher than 10%, while strains 6, 9 and 25 could grow at the condition at which the pH was lower than 2.5 or the salty concentration was higher than 14%. The proper growth temperture of strains 6, 9 and 25 was during 30℃to 37℃; the proper growth temperture of strains 17, 19 and 22 was during 25℃to 30℃.By the fermenting of turnip inoculated with different compound bacteria as fermentation agent , the results showed that: the compounds contianed strain 22 produced acid more quickly than other compounds at the prophase, while the compounds without contianed produced acid more and quicker at the anaphase of fermentation. But all of the compounds had a fluctuation of pH at the anaphase of fermentation. Maybe it was for their growth cycles and accumulation of metabolites. The content of amino acid was higher and Vc was affluent in the turnip pickle, meanwhile they lost little during the process of fermentation. Overall, compound 3 and coupound 15 were selected as excellent fermenting agent.Compared to the fermentation of both excellent fermenting agents , it appeared that inoculated fermentation was best at 12℃to 15℃. Though the cycle of fermentation was longer at the lower temperture, it could avoid rancidification and restrain other microbe to grow. Importantly. It can prolong the guarantee period. The nitrite content of turnip inoculated was lower evidently than that of natural fermentation.Through the analysis, the flavor of pickle was decided by the interaction of every component , not by one kind or one flavor substance. And it is a important study of fermenting vegetable that which flavor component has a prominent effect to the flavor of pickle.