泡菜发酵过程中硝酸盐还原酶活性的研究

Study on nitrate reductase activity during the fermentation of pickled vegetable

在泡菜进行自然发酵的过程中,无论是泡菜组织内的硝酸盐还原酶,还是卤汁中细菌菌体内的硝酸盐还原酶,两者的活性变化趋势基本相似,即由小逐渐增大,到发酵的第96小时达到最大值,然后迅速下降并维持一较低的水平。其中,泡菜组织内的硝酸盐还原酶活性的最大值为10μg/g,而卤汁中细菌菌体内的硝酸盐还原酶活性的最大值为8μg/g。同时测定泡菜中亚硝酸盐含量的结果表明,泡菜“亚硝峰”出现的时间与酶活最大值出现的时间相吻合,也是在发酵的第96小时。进一步测定发酵液的pH值、卤汁中菌落总数以及泡菜中硝酸盐含量,实验结果表明,泡菜中亚硝酸盐含量不仅与卤汁中的细菌有关,与泡菜原料也有重要关系,为合理控制泡菜中亚硝酸盐的含量找到一条有效的途径。

During the fermentation, both of the vegetable nitrate reductase and the bacteria nitrate reductase showed the same activity pattern. Both enzyme forms′ activity gradually increased and reached a peak at the 96th hour after fermentation and then declined. In the same time, the concentration of nitrite was determined. As forecasted, it showed a similar pattern to the enzymes′, and peaked at the same time. It was proposed that the concentration of nitrite might have a close relationship not only with the bacteria but also with the rough material, suggesting a good way to control the nitrite concentration in pickled vegetables.