Production of a vinegar from onion

摘要

Various conditions for onion-juice production, and for alcohol and acetic acid fermentations were investigated to produce a vinegar from onion. In the production of the onion juice, treatments with enzymes such as 0.6% Celluclast 1.5L and 0.2% Viscozyme L increased the yields significantly from 45.0% to 54.5% and 72.5%, respectively. Alcohol and acetic acid fermentations from the onion juice were effectively improved by using the onion juice heated at 80 deg C for 10 minutes, and by adding 0.3% yeast extract, 0.3% MgSO_4 and 0.3% K_3PO_4 as nutrients to the onion juice. At the optimum condition, 5.8% alcohol was produced after five days of fermentation at 30~C from the 14 deg Brix onion juice, which was adjusted by adding sugar. A vinegar with 6.7% acetic acid content was produced after 20 days of fermentation at 30 deg C from 4% alcohol that was adjusted by adding onion juice.