摘要
研究了乳酸质量浓度和p H对清香型大曲酯化酶活力的影响,结果表明,乳酸质量浓度对大曲酯化酶活力有很大影响,当乳酸质量浓度较低时,大曲中的酯化酶表现为合成作用,分别在低于8 g/L和16 g/L时催化乳酸乙酯和乙酸乙酯的合成;当乳酸质量浓度较高时,酯化酶表现为水解作用,将酯分解为相应酸和醇;p H对大曲酯化酶酯分解活力影响显著,在p H值为2.0时,酯的分解主要为化学分解,在p H值为3.0~6.0时,化学分解和酯化酶分解都起作用。实验发现在p H值为4.0时大曲酯化酶催化乙酸乙酯合成的活力最强,100 h时乙酸乙酯质量浓度达188.8 mg/L;p H值为5.0时催化乳酸乙酯合成的活力最强,100 h时乳酸乙酯质量浓度达182.6 mg/L。
The effects of lactic acid concentration and pH on esterifying enzymes activity were discussed. The results showed that, the lactic acid con- centration had great effect on esterifying enzymes activity of Daqu. When the lactic acid concentration was low, the esterifying enzymes showed syn- thesis effect, catalysing ethyl lactate （lactic acid less than 8 g/L） and ethyl acetate （lactic acid less than 16 g/L） synthesis, When the lactic acid concen- tration was high, the esterifying enzymes showed hydrolysis effect, so the ester was decomposed into acid and alcohol, pH showed significant effect on esterifying enzymes decomposition activity of Daqu, the decomposition of the ester was mainly chemical decomposition at pH 2.0, and chemical decomposition and esterifying enzymes decomposition both play a role at pH 3.0-6.0. The optimum pH for ethyl acetate synthesis by esterifying enzymes was 4.0. which nrodueed 188.8 mg/L ethyl acetate at 100 h, and for the pH 5.0 buffer, it produced 182.6 mg/L ethyl lactate at 100 h.
出处
《中国酿造》
CAS
北大核心
2017年第1期35-38,共4页
China Brewing
基金
国家自然科学基金资助项目(3147172)
中国白酒3C计划项目
关键词
清香型大曲
酯化酶
合成
分解
light-flavor Daqu
esterifying enzymes
synthesis
hydrolysis
