大米精白度对酶法酿造米酒风味品质的影响

Effect of Rice Polishing Degree on Flavor Quality of Enzymatically Brewed Rice Wine

摘要:

不同精白程度的大米在营养成分上有显著差异。为探究大米精白度对酶法酿造米酒风味品质的影响，使用5种不同精白度的大米（0、10%、20%、30%、40%）进行酶法酿造米酒，并从理化指标、游离氨基酸质量浓度、挥发性风味物质质量浓度和感官评价4个方面分析米酒风味品质的变化。结果表明，随着大米精白度的增加，米酒乙醇体积分数和总糖质量浓度升高，氨基酸态氮质量浓度下降；游离氨基酸质量浓度和高级醇质量浓度分别由1 346.17 mg/L和4 033 μg/L降至1 063.85 mg/L和3 119 μg/L，同时醇酯比也由1.24降至0.98，有利于提升米酒的口感；含硫氨基酸蛋氨酸和半胱氨酸质量浓度分别减少了50.8%和59.3%，有助于提高米酒储藏稳定性并改善其新鲜度；乙酸异戊酯质量浓度由254.19 μg/L提高至406.91 μg/L，改善了米酒的风味。最后，通过感官评价验证了上述结论，发现适度精白的大米所酿造的米酒具有更丰富的花香和果香，其口感也更加柔和。综上所述，适度提高大米的精白度能够有效改善米酒的气味和滋味，从而提升其整体风味品质。

Abstract:

Rice with different polishing degrees shows significant differences in nutritional composition. To explore the effect of rice polishing degree on the flavor quality of enzymatically brewed rice wine, five kinds of rice with different polishing degrees (0, 10%, 20%, 30%, 40%) were used to brew rice wine by enzymatic fermentation. The changes in rice wine flavor quality were analyzed from four aspects: physical and chemical indexes, free amino acids mass concentrations, volatile flavor substances mass concentrations, and sensory evaluation. The results showed that with the increase in rice polishing degree, the ethanol volume fraction and total saccharide mass concentration in the rice wine increased, while the amino acid nitrogen mass concentration decreased. The mass concentrations of both free amino acids and higher alcohols decreased from 1 346.17 mg/L and 4 033 μg/L to 1 063.85 mg/L and 3 119 μg/L, respectively, while the alcohol-to-ester ratio dropped from 1.24 to 0.98, which contributed to an improved flavor profile of the rice wine. The mass concentrations of sulfur-containing amino acids methionine and cysteine decreased by 50.8% and 59.3%, respectively, which helped improve the storage stability and freshness of the rice wine. The mass concentration of isoamyl acetate increased from 254.19 μg/L to 406.91 μg/L, improving the volatile flavor of the rice wine. Finally, sensory evaluation confirmed the above conclusions, revealing that the rice wine brewed from moderately polished rice exhibited richer floral and fruity aromas, with a smoother taste. In summary, moderately increasing the rice polishing degree can effectively improve the aroma and taste of rice wine, thereby enhancing its overall flavor quality.