大曲热风干燥工艺的优化

Process Optimization for Hot-air Drying of Daqu

本项目采用均匀优化试验设计方法优化了大曲分阶段变温干燥工艺,探究了工艺参数对大曲能耗指标、质量指标、挥发性风味指标和微生物指标的影响。研究结果表明:干燥第一和第二阶段温度的交互作用对大曲能耗的影响最大,而第一与第二阶段风速的交互作用对大曲质量指标的影响最大,第一阶段温度与第二阶段风速的交互作用对大曲挥发性风味指标的影响最大,且微生物指标很容易受干燥工艺参数的影响;通过评价函数法将大曲各个评价指标进行综合规范化,发现干燥第一与第二阶段风速的交互作用对大曲综合指标函数的影响最大,大曲综合指标函数得分最高值为1.367分,此时最佳大曲干燥工艺参数为:干燥第一阶段温度为47.8℃、第一阶段风速为1.3 m/s、水分含量转换点15.5%、第二阶段温度为45.0℃、第二阶段风速为0.3 m/s。最终获得的成品曲曲香纯正浓郁,断面整齐,菌丝生长良好,达到优质曲要求。

In this project, the uniform optimization experiment design method was used to optimize the staged temperature-variable drying process of Daqu, and the influence of process parameters on the energy consumption, quality, volatile flavor and microbial indices of Daqu was explored. Results showed that the interaction of the first stage temperature and the second stage temperature had the greatest impact on the energy consumption of Daqu, the interaction between the first stage wind speed and the second stage wind speed exerted the greatest impact on the Daqu quality indices, the interaction between the first stage temperature and the second stage wind speed had the greatest impact on Daqu＇s volatile flavor index, and the microbial index was easily affected by drying process parameters; Through function evaluation, the evaluation indices of Daqu were comprehensively standardized, and it was found that the interaction between the first stage wind speed and the second stage wind speed had the greatest influence on the comprehensive evaluation indices of the Daqu. The highest comprehensive index function score of Daqu was 1.367, where the optimal Daqu drying process parameters are： The first stage temperature was 47.8 ℃, the first stage wind speed was 1.3 m/s, the water content conversion point was 15.5%, the second stage temperature was 45.0 ℃, and the second stage wind speed was 0.3 m/s. The finished Daqu product was pure and rich in flavor with a neat section and well-grown mycelium, thus, met the requirements of high quality Daqu.