Optimization of acetic acid fermentation parameters for production of persimmon vinegar

In order to study the variation regularity of fruit vinegar production with persimmon pulp and provide theoretical foundation for persimmon processing, response surface methodology was applied to optimize the technical parameters of acetic acid fermentation for producing persimmon vinegar with Diospyros kaki L. as the raw material. The results show that both acetic acid bacillus inoculation quantity and fermentation time have noticeably significant effects on acetic acid content (p<0.01), but fermentation temperature has no significant effect on acetic acid content. The optimal fermentation parameters are as follows: fermentation temperature 33.1℃, acetic acid bacillus inoculation quantity 0.56‰ and fermentation time 110 h. Under these optimized conditions, the acetic acid content of persimmon vinegar is 4.928 g/(100 mL).The results of multivariate regression analysis show that the model for regressing fermentation temperature, acetic acid bacillus inoculation quantity, fermentation time and acetic acid content is remarkable. Practical production of acetic acid content of persimmon vinegar can be forecasted by applying the model.