양파식초 제조를 위하여 농축시료(A)와 보당시료(B)로 구분하여 알콜 및 초산발효를 2단계 과정으로 구분하여 성분 변화를 조사하였다. 유리당은 농축시료(A)는 glucose 4.1, fructose 4.2 및 sucrose 0.6%이었으며, 보당시료(B)는 각각 3.2, 3.3 및 4.6%로 발효가 진행됨에 따라 유리당의 함량은 점차 감소하는 경향을 나타내었으며, sucrose, glucose, fructose 순으로 모두 소비되었다. 환원당과 총당은 발효기간이 경과됨에 따라 점차 감소하여 알콜발효 36시간에 농축시료(A)에서는 각각 0.5 및 0.8%이었고, 보당시료(B)에서는 각각 0.4 및 0.6%이었으며, 그 이후에는 (A),(B) 두 시료 모두 큰 변화가 없었다. 알콜발효시 알콜함량은 두 시료 모두 발효 12시간부터 급격하게 증가하여 농축시료(A)는 발효 36시간만에 7.0%, 보당시료(B)는 발효 48시간만에 8.2%로 가장 높게 나타난 후 감소하는 경향이었다. 알콜성분은 acetaldehyde, methanol, ethanol, n-propanol, iso-butanol, iso-amylacohol 등이 분석되었다. 유기산은 농축시료(A)와 보당시료(B)에서 모두 acetic acid 함량이 보당시료(B)에 비해 높게 나타났다. 이상의 결과에서 양파를 원료로하여 농축과 보당처리에 따른 양파식초제조시 품질에 따른 차이는 크게 없었으나, 농축시료를 이용한 양파식초는 과잉생산에 따른 양파소비증대 방안으로 적합할 것으로 생각된다.
Changes in components of onion vinegar during two-stage fermentation were investigated. One sample group (A) was prepared with onion juice by extraction and concentration (15 brix), and the other group (B) was prepared using the same method but supplemented with sucrose. Comparison of glucose (4.1%), fructose (4.2%), and sucrose (0.6%) found in A as major sugars with those (3.2, 3.3, and 4.6%, respectively) of B showed a significant difference in sucrose concentration. During alcohol fermentation, S. kluyvery DJ97 consumed these sugars completely. At 36 hr of alcohol fermentation, concentrations of reducing and total sugars decreased to 0.5 and 0.8%, in A, and 0.4 and 0.6%, in B, respectively. No further changes were detected in the concentrations of these sugars thereafter. From 12 hr of fermentation, alcohol concentrations in groups A and B increased markedly, maximizing at 7.0% at 36 hr A and at 8.2% at 48 hr in B, and finally decreased thereafter in both groups. The detected alcohol components were ethanol, acetaldehyde, methanol, n-propyl alcohol, iso-butanol, and iso-amyl acohol. During acetic acid fermentation, the concentration of acetic acid as the major organic also increased significantly in both groups (4,776.72 and 4,894.93 mg% in A amd B, respectively). Other organic acid contents such as malic and succinic acids were higher in A than B. these results indicate that vinegar is better produced in onion extract with no sucrose supplementation based on its organic acid contents.
