The Change of Thiocyanate (Goitrogen) Amount, Indolylmethyl Glucosinolate Content and Myrosinase Activity in Redish Kimchi during Fermentation

무우김치 숙성 중 thiocyanate(gitrogen)함량, 기질(indolylmethyl glucosinolate) 함량 및 myrosinase 활성도 변화에 관한 연구

The study on the change of general properties of Kagdugi during dfermentation reveals that around the third day of fermentation, optimum for good flavor, the pH decreased to around or below 4 while the acidity increased gradually. The relative amount of thiocyanate in the radish Kimchi homogenate decreased to 73% after 1 day and after 3 days to 32% of control. And the content of indolylmethyl glucosinolate and total myrosinase activity in the tissue of radish Kimchi decreased gradually and on 3rd day to 25% and 4% of control, respectively. On the other hand the concentration of ascorbic acid in the radish Kimchi was found to vary around 1mM. Based on these results, the gradual decline of thiocyanate formation in the radish Kimchi homogenate is concluded to be caused by the gradual decomposition of indolylmethyl glucosinolate and the decline of myrosinase activity, which are directly affected by the change of pH during fermentation.

깍두기 숙성 중 thiocyanate 함량 및 thiocyanate 생성에 영향을 주는 인자들의 변화를 측정하였다. 관능검사 결과, 숙성 적기는 3일로 판정되었으며, 이 시기의 pH는 3.8, 산도는 16.1mEgNaOH/100g이었다. 무우중의 thiocyanate 함량은 0.44∼2.28mg/100g이었으며 깍두기중의 thiocyanate함랑은 숙성 1일에 73%, 숙성 3일에 32%로 감소하였다. Thiocyanate 생성에 관여하는 indolylmethyl glucosinolate 함량 및 myrosinase 활성도는 깍두기 숙성 중 점차 감소하여 각각 25% 및 4%에 달하였으나, myrosinase의 조효소로 작용하는 아스코르브산의 함량은 숙성기간 중 약 1mM 정도를 유지하였다. 따라서, 깍두기 숙성 중 thiocyanate 생성 감소 현상은 김치 숙성 중 pH 감소에 의한 indolylmethyl glucosinolate의 분해와 myrosinase의 불활성화에 기인되었다.