响应面优化药食同源基质制曲工艺及酒体成分分析

Optimization of Koji-Making with Culinary Medicinal Matrices by Response Surface Methodology and Component Analysis of Rice Wine

以12 种药食同源物质为制曲基质,研究根霉接种量、基质含水量、培曲时间和培曲温度对实验曲糖化酶和液化酶活力的影响。在单因素试验基础上,采用Box-Behnken试验设计原理,以糖化酶活力为响应值,对制曲工艺条件进行优化。结果表明,最佳工艺条件为根霉接种量0.3%、培曲时间40 h、基质含水量65%和培曲温度28 ℃,在此条件下糖化酶活力预测值为778.65 mg/(g·h)。最佳培曲条件经过3 次验证实验,所得糖化酶活力实测平均值为(779.233±0.577)mg/(g·h),实测值与预测值较为接近,说明此方案可行。且实验曲糖化酶和液化酶活力分别约为传统曲的1.3 倍和2.8 倍。对传统曲酿造米酒和实验曲酿造米酒的33 种酒体成分进行检测,其两种曲酿酒差异最大的物质分别为异戊醇(10.065、109.394 μg/100 mL)、丁酸乙酯(0.867、187.552 μg/100 mL)、乙酸(135.240、560.939 μg/100 mL)、苯酚(0.156、0.858 μg/100 mL)。综合以上结果,实验曲具有良好的发酵性能,所酿造米酒具有更加丰富的滋味,有较好的开发前景。

Twelve kinds of culinary medicinal plant matrices were used as new substrates for making koji. The effect of Rhizopus inoculum size, matrix moisture content, cultivation time and temperature on glucoamylase and liquefaction enzyme activity was examined. Optimization of the process conditions was carried out by the combined use of single factor method and the Box-Behnken design. Glucoamylase activity was used as the response value. The results showed that the optimum process conditions were determined as follows: inoculum size 0.3%, culture time 40 h, matrix water content 65% and culture temperature 28 ℃. Under these conditions, the predicted value of glucoamylase activity was 778.65 mg/(g·h), while the average of three replicate experiments was (779.233 ± 0.577) mg/(g·h). This good agreement indicates that this scheme is feasible. The glucoamylase and liquefaction enzyme activity measured were about 1.3 and 2.8 times higher than that of traditional koji, respectively. A total of 33 volatile components were detected from the two rice wines. Isoamyl alcohol (10.065 versus 109.394 μg/100 mL) and ethyl butyrate (0.867 versus 187.552 μg/100 mL), acetic acid (135.240 versus 560.939 μg/100 mL) and phenol (0.156 versus 0.858 μg/100 mL) showed the greatest differences between the two rice wines. Based on the above results, the new koji had good fermentation performance and the brewed rice wine had a richer taste, showing that this koji to be a promising starter culture for rice wine.