Changes of Aroma Compounds during Kimchi Powder Production and Encapsulation Effect of β-Cyclodextrin

The aim of this study was to investigate the change of volatile aroma compounds in kimchi during fermentation, before and after drying process. Also, the encapsulation effect of cyclodextrin on volatiles during the drying process was examined. GC-MS was used for detection and identification of volatile compounds. During kimchi fermentation, in the early stage, dimethyl sulfide, carbon disulfide were detected as major compounds and after 7 days several sulfur compounds, dimethyl disulfide, methyl 2-propenyl disulfide, allyl methyl sulfide, and di-2-propenyl disulfide bacame the major volatiles. After vacuum-drying, the kimchi powder lost 11 compounds but still retained 13 volatiles of which major compounds were dimethyl sulfide, acetaldehyde and methanethiol. In order to keep volatiles in kimchi powder along with the drying process, 0.25-1.0% cyclodextrin was added in kimchi and dried-kimchi was prepared by using vacuum dryer. Cyclodextrin acted as an encapsulation agent for aroma compounds and it resulted in less loss of volatiles during drying process. Addition of cyclodextrin will permit industry-scale production of dried-kimchi powder with less loss of aroma compounds.

김치 감압건조 시 향기성분의 변화 및 β-cyclodextrin의 향기성분 포집효과

본 연구는 김치건조분말을 제조하는 과정에서 김치의 발효과정과 건조 전후에서 나타나는 향기성분의 변화를 조사하고, $\beta$-cyclodextrin의 첨가로 인한 향기성분 포집효과를 검증하고자 GC-MS를 이용하여 분석실험을 실시하였다. 김치를 제조하여 $20^{\circ}C$에서 발효시켰을 때, 초기 2일째는 dimethyl sulfide와 carbon disulfide가 생성되었고, 7일이 경과하였을 때, dimethyl disulfide, methyl 2-propenyl disulfide, allyl methyl sulfide, and di-2-propenyl disulfide의 황화합물이 주된 향기성분으로 검출되었다. 본 김치시료를 감압건조 하였을 때, 11개 화합물이 검출되지 않았고 dimethyl sulfide, acetaldehyde and methanethiol를 주로 포함하는 13개 화합물이 잔류하였다. 건조공정 중에서 김치향기성분의 손실을 최소화하고자 0.25-1.0% 농도의 $\beta$-cyclodextrin을 건조보조제로 첨가하였을 때, 향기성분의 포집효과에 의해 건조 김치분말에 잔류하는 향기성분의 함량이 평균 3% 증가하였다. 본 연구결과로 볼 때 cyclodextrin은 건조 김치분말 제조공정뿐만 아니라 건조식품제조에서 건조보조제로 효과적으로 사용할 수 있을 것으로 보인다.