Study of Fermented Vinegar from Glutinous Rice Koji

Abstract

Vinegar is fermented food product. It has been used as food condiment and also beverage. The aim of this study was to study the production of traditional fermented glutinous rice vinegar. Fermentation of glutinous rice vinegar started from rice koji production using 0.1% (w/w) of Aspergillus oryzae L spore, followed by saccharification at 60 °C. After that, alcohol fermentation using 1% (w/w) of Sacharomyces cerevisiae, and acetic acid fermentation using 10% (v/v) of Acetobacter aceti were processed, respectively. There were 3 types of rice used in the experiment, hang glutinous rice, white glutinous rice, and black glutinous rice. The result showed that black glutinous rice showed high potential to use for fermented rice vinegar. Using black glutinous rice showed high amylase activity at 0.821 unit / g dry weight at 3 days of koji production. It also showed the highest total soluble soid at 20 °Brix after 25 h of saccharification and 14% alcohol content after 5 days of alcohol fermentation. Finally, vinegar from black glutinous rice contained 5.16% of acetic acid after 3 days of acetic acid fermentation. However, all of glutinous rice used in this study could be used as raw material of glutinous rice vinegar fermentation because they can provide product quality reach to the standard.