Production of high-acidity peach vinegar by improving the manufacturing process of “Dochobang”

Abstract

According to the method described in the ancient literature "Imwonsipyukji", 'Dochobang' was mainly composed of lactic acid (756.81 mg/100 mL) and acetic acid (473.66 mg/100 mL) as the main organic acids on the 14th day of fermentation. The acidity of 'Dochobang' was 1.09%, resulting in low marketability. Therefore, this study aimed to improve the manufacturing process of peach vinegar and optimize the conditions, including temperature and initial pH, for producing high-acidity vinegar using fermented seeds. We first selected yeasts (Saccharomyces cerevisiae YM27) with excellent alcohol fermentation ability and acetic acid bacteria (Acetobacter oryzifermentans (KACC19301)) with remarkable acid-producing ability and used these in the process-improved two-stage fermentation. The experiment was conducted by 3 treatments of tepmerature(20℃, 30℃ and 35℃) and initial pH(3, 4 and 5) for acetic acid fermentation. 'Dochobang' fermented alcohol and acetic acid at the same time by natural fermentation. on the other hand, peach wine starter and seed vinegar were added before each fermentation step to increase acetic acid production. Wines fermented at 25℃ and 30℃ were found to be 9% alcoholic on days sixth and nine days, respectively. Organic acid analysis revealed that the level of acetic acid in vinegar fermented at pH 4 and 20℃ increased steadily until day 14 (6,171.3 mg/100 mL). The acidity was 7% on the 21st day of fermentation. Furthermore, as the fermentation progressed, the umami and sourness of the peach vinegar increased. We expect that our findings could improve the quality of peach vinegar recorded in the old literature and can be used in small-scale agricultural companies.