Changes in lipid component and quantitative measurement of carbonyl compound during Doenjang fermentation

된장 숙성 중 지질의 변화 및 카보닐 화합물의 함량 변화

Conventional Doenjang, improved Doenjang prepared with Asp. oryzae were made to investigate the changes in the lipid content, and the carbonyl compounds during fermentation. Total lipid contents of conventional Doenjang increased slowly during fermentation, and that of the improved Doenjang increased at first, but showed sharp decrease at moment and then increased. Triglyceride contents of all samples decreased remarkedly during fermentation. Conversely, free acid contents increased. From the result of quantitative analysis of fatty acid by gas chromatography, saturated fatty acid ratio of total lipid in conventional Doenjang increased at early stages and then decreased, but unsaturated fatty acid ratio showed the reverse phenomenon. Saturated fatty acid in improved Doenjang increased during the fermentation but unsaturated fatty acid decreased by degrees. The concentration of total and monocarbonyl compounds in the fermented Doenjang were comparably higher than that found in raw Boenjang. Sensory evaluation revealed that off flavor had a negative effect on overall eating quality of Doenjang and total carbonyl content was related to the off flavor.

본 연구에서는 재래식 된장, AsP. oryzae를 이용한 개량식 된장을 만들어 숙성과정 중 지질의 변화와 카보닐화합물의 함량변화를 측정하였다. 1 재래식 된장의 총지질 함량은 숙성에 따라 점차 증가하였고 지질 중의 중성지방은 감소하였으나 유리지방산은 증가하였다. 2. 지방산 조성을 GC로 분석한 결과 포화지방산이 증가하고 불포화 지방산은 감소하였다. 3. 숙성 후 hexane으로 추출한 카보닐의 함량은 증가하였고 monocarbonyl 중 methyl ketone과 alkanal만이 검출되었고 그 함량은 숙성 후 증가하였다.