Processing and quality analysis of pickled Chinese cabbage fermented with low temperature tolerant lactic acid bacteria

At low temperature conditions of 10 ℃,two isolates of low temperature tolerant lactic acid bacteria( LAB) 3m-1( L. plantarum),and 8m-9( L. mesenteroides) were proved to grow simultaneously in Chinese cabbage extract medium without antagonism and thus were selected for fermentation in pickled Chinese cabbage. After the two LAB strains were inoculated alone or simultaneously in processing of pickled Chinese cabbage,the dynamic variation of acid production,nitrite degeneration and fermentation flavor of the pickled Chinese cabbage were analyzed to select starter culture for subsequent study. The results indicated that the quality of Chinese pickled cabbage fermented with LAB starter culture was superior to that from natural fermentation. The nitrite content dropped to a low level compared to natural fermentation. sensory evaluation showed that flavor of pickles fermented with 8m-9 or 3m-1 and 8m-9 mixed with 2∶ 1 ratio was superior to those of the other groups. The orthogonal experiment determined the optimal processing parameters,which were salt addition of 4%,sugar addition of 4%,and 0. 3% of starter culture of 8m-9 strains,or which were salt addition of 5%,sugar addition of 2%,and 0. 3% of starter culture of 3m-1 and 8m-9 at a ratio of 2∶ 1. Using starter culture mentioned above,the physiochemical index,microorganism index and sensory indicator were analyzed at 10 ℃ and 30 ℃. The results showed that pickle had suitable acid content and lower content of nitrite at10 ℃. Although the fermentation period was long,the pickle owned better flavor,and the growth of unfavorable mixed bacteria in the pickle was inhibited at low temperature condition.