Quality characteristics of makgeolli under nutrient deficiency and high-temperature fermentation

The objective of this study was to evaluate the quality characteristics of makgeolli under conditions of nutrient deficiency and high-temperature fermentation. Makgeolli was prepared using rice, water, enzyme (glucoamylase), and yeast (La Parisienne, WB06). These ingredients were mixed and fermented for 6 days at 25°C, followed by 3 days each at 25°C, 35°C, and 45°C. The WB06 treatment resulted in lower alcohol content, with higher temperatures during the last 3 days of the 9-day fermentation process, further suppressing alcohol production. Conversely, the content of reducing sugar was highest when WB06 was fermented at 25°C. Although the lactic acid content of the alcoholic beverage made with WB06 was high, the elevated sugar content resulted in a suitable sugar-acid ratio. Yeast remained viable even when fermented at a high temperature of 45°C. This study demonstrated the feasibility of producing low-alcohol beverages with viable yeast cultures with nutrient deficiency and high-temperature fermentation.