Quality characteristics of Kujippong (Cudrania tricuspidata) vinegar fermented by various acetic acid bacteria

Abstract

In this study was we investigated the optimum conditions for the fermentation of Kujippong (Cudrania tricuspidata) vinegar by various acetic acid bacteria (Acetobacter pasteurianus A26, A37, B7) and its quality characteristics. Fermentation at various initial acidities (pH 2, 3, and 4) and temperatures (20°, 30°, and 35°) revealed that A. pasteurianus A37 and B7 produced the most acetic acid when fermented at pH 4 and 20°. The acidities of the Kujippong fermented vinegars prepared with the A37 and B7 strains increased by 6.3% and 6.1%, to pH 2.45 and pH 2.43, respectively. Meanwhile, the vinegar produced by the A26 strain showed low acidity under all conditions. At the end of fermentation period, the acetic acid content of the main organic acid had increased by a factor of ten from day 0, to values of 37.34 mg/mL for A. pasteurianus A37 and 39.34 mg/mL for B7. The A37 and B7 strains produced 37.5% and 59.2% volatile components, respectively, which were mainly acetic acid and its ethyl ester, among a relatively diverse range of volatile compounds produced. Therefore, the good aceitc acid production of farm-made Kujippong-fermented vinegar is expected to promote the consumption of local agricultural products and and increase in farm income.