凤型大曲酯化力测定方法研究

Study on Determination Method of Esterifying Ability of Feng-flavour Daqu

以乙酸为底物酸,通过单因素试验考察了大曲量、乙酸浓度、乙醇浓度、酯化温度、酯化时间对凤型大曲酯化力测定结果的影响,并采用正交试验法进行了条件优化。结果表明:酯化力测定最佳条件为:大曲量20 g、乙酸浓度2.0%、乙醇浓度20%、28℃酯化5天;该条件下酯生成量为7.33±0.03 g/L,酯化力为915.66±3.43 U。该方法日内、日间精密度(relative standard deviation,RSD)分别为2.63%和2.24%,且应用于8种不同凤型大曲时RSD值均小于5%,重复性和稳定性较好。研究首次探究了凤香型大曲的酯化酶特性,也为不同香型大曲酯化力测定方法的选择提供了技术参考。

The effects of Daqu amounts,acetic acid concentration,ethanol concentration,esterification temperature and esterification time on ester production were investigated by single factor experiment with acetic acid as substrate acid;then the method was optimized via orthogonal test.The results showed that:The optimum esterification conditions were:Daqu 20g,acetic acid concentration 2.0%,ethanol concentration20%,esterification at 28℃for 5 days;at that conditions ester production and esterifying ability of Feng-flavour Daqu were 7.33±0.03 g/L and 915.66±3.43 U,respectively.The intra-day and inter-day precision(relative standard deviation,RSD)of this method were 2.63%and2.24%,respectively;and the RSD value of this method were all less than 5%when it was applied to 8 types of Feng-flavour Daqu,which exhibited a good repeatability and stability.This work explored firstly the esterase characteristics of Feng-flavour Daqu,which also provided a technical reference for the determination methods selection of esterifying ability of Daqu with various flavors.