Optimization of Fermentation Condition for Onion Vinegar Using Acetobacter orientalis MAK88

Acetobacter orientalis MAK88 균주를 이용한 양파 식초의 발효 최적화

Acetic acid bacteria strains were isolated from a variety of fermented foods and fallen fruits. Among them, the strain MAK88, whose acetic acid fermentation ability, acid-tolerance, and alcohol-tolerance were high, was selected and identified as Acetobacter orientalis. A seed culture of A. orientalis MAK88 was inoculated into onion juice, and the optimum conditions of acetic acid fermentation was investigated. The optimum initial concentration of ethanol in onion juice was 5% (v/v) and in that condition, acidity was 4.31% at 144 h of fermentation. The optimum initial concentration of acetic acid was 1% and the final acidity was 5.32%. The optimum fermentation temperature was determined to be $28^{\circ}C$. The most appropriate preparation method of onion juice was to heat the onion at $121^{\circ}C$ for 15 min and produce juice with pressure followed by filtering, and then sterilization at $121^{\circ}C$ for 15 min. Prepared onion juice was used for fermentation without dilution.

양파를 이용하여 식초를 제조하기 위하여 막걸리로부터 분리된 내산성과 내알코올성이 우수하고 산생성능이 높은 Aectoacter orientalis MAK88를 사용하였다. 양파 추출액에 A. orientalis MAK88의 종배양액을 접종하여 초산 발효를 실시하였을 경우, 발효 최적 조건을 조사하였다. 앙파 추출액 중의 초기 에탄올 농도는 5% (v/v)가 최적이었으며, 발효 144시간에서의 산도는 4.31%이었다. 초기 초산 농도는 1% (v/v)가 최적으로 발효 144시간에서의 최종 산도는 5.32%였다. 최적 발효온도는 $28^{\circ}C$로 확인되었다. 양파 착즙액은 통 양파를 $121^{\circ}C$에서 15분간 가열한 뒤 가압 착즙 후 여과한 다음 $121^{\circ}C$에서 15분간 살균하여 제조한 것이 발효에 가장 적합하였으며, 희석하지 않은 착즙 원액을 사용하는 것이 가장 좋았다.