Abstract
Changes of quality properties of fermented tofu prepared with two molds like Actinomucor elegans (AE) and Rhizopus oligosporus (RO) and coagulants (CaCl$_2$ and citric acid) were investigated. Moisture and crude protein of fermented tofu were rapidly decreased during fermentation, the contents of crude lipid and crude ash were shown to be slightly increased, ad then total acidity was slowly decreased. The content of reducing sugar of fermented tofu was slowly increased for 7 day of fermentation, but rapidly increased after that time because of rapid hydrolysis of carbohydrate in fermented tofu. The contents of amino and ammonia type nitrogen were quickly increased during fermentation. The highest contents of amino type nitrogen of fermented tofu were found in sample of CaCl$_2$group as a coagulant and RO group as a mold. Contents of minerals in tofu fermented for 14 day were high in order of K>Ca>Mg>Na. Iin conclusion, AE was more effective than RO to enhance the contents of reducing sugar and amino type nitrogen as an indicator of fermentation within 7 day of fermentation, and then RO was more effective than AE after that time. Calcium chloride as a coagulant was more effective than citric acid in tofu fermented with the same strain for 14 day.
균주(Act. elegans, Rhi. oligosporus)와 응고제(CaCl$_2$, citric acid)를 달리하여 제조한 발효두부의 품질특성을 조사하였다. 발효두부의 수분과 조단백질은 발효시간이 증가할수록 빠른 속도로 감소하였으며, 조지방과 조회분은 약간 증가하였다. pH는 발효가 진행됨에 따라 서서히 증가하는 경향을 보였고, 총산은 감소하였으나 시험구간별 뚜렷한 차이점은 없는 것으로 나타났다. 환원당은 발효 7일째가지는 서서히 증가하였으나 그 후 14일째까지 급속히 증가하였고, 아미노태 질소 및 암모니아태 질소 역시 바르게 증가하였다. 무기성분은 K>Ca>Mg>Na 등의 순으로 높게 나타났으며, 각 군별 뚜렷한 차이는 보이지 않았다. 결론적으로 발효도의 지표인 환원당과 아미노태 질소함량을 증가시키기 위해서는 단기발효(7일)에서는 Act. elegans가 Rhi. oligosporus보다 효과적이었고, 장기발효(14일)에서는 반대경향을 나타내었다. 응고제는 동일균주로 장기발효를 할 경우 CaCl$_2$가 citric acid보다 효과적이었다.