Acetobacter pasteurianus NPUST S21之生長條件及醋酸發酵之探討

Abstract

Vinegar, also known as xi, is regarded as the herbal medicine, which can disinfect and digestive role in China. Nowadays, many people work hard for long time and get stressful, who could easily get tired because of the accumulation of lactic acid and pyruvic acid. In the recent study reported the healthy benefits about the fermented vinegar containing organic acids which support TCA cycle. In this research, isolated the strain which had the strongest activity named Acetobacter pasteurianu NPUST S21. To improve the way of traditional fermentation starters, we use immobilization for applying, and developing the new product of solid-state fermented vinegar. The optimal medium contained 2% glucose, 1% yeast extract, 0.1% sodium acetate, 0.2% glycerol, alcohol 6%. The fermentative conditions were that medium initial pH 5.0 ± 0.5, inoculum size 3%, temperature 33℃and shaking speed 125 rpm in flask. After 48 hours fermentation, the maximum concentration of acetic acid was 6.4% (w/v). Comparing the acetification and survival rate , the best immobilized condition was that used corncobs as a substrate soaked in 20% alcohol solution for 5 hours, and immobilized the bacteria at 30℃, 150 rpm, for 12hours, respectively. In solid-state fermentation, red sorghum, buckwheat and wheat as materials, which adjusted 50% of initial moisture content and then mixed with 20% crops. The vinegar was fermented in 30℃, inoculum size 30%, for 40 days. After 3 months aging, the vinegar will be analyzed and sensory test. The results shows that solid-state fermented vinegar is better acceptance than others.