This study studied the brewing suitability of Baromi2 as a raw material for fermented liquor by analyzing the quality characteristics of Nuruk using Baromi2, a powdered rice variety developed by the government, and the quality characteristics of ferme...
This study studied the brewing suitability of Baromi2 as a raw material for fermented liquor by analyzing the quality characteristics of Nuruk using Baromi2, a powdered rice variety developed by the government, and the quality characteristics of fermented liquor to which it was applied. By manufacturing Nuruk with different mixing ratios of Baromi2 and Samgwang, various microbial communities such as product temperature change, pH, acidity, saccharogenic power, enzyme activity, and microbial community. Based on this, optimal Nuruk was selected, and fermentation and aging characteristics were analyzed by manufacturing fermented liquor with Samgwang and Baromi2 as the main ingredient.
Nuruk using Baromi2 decreased after peaking at 43.5 °C to 46.5 °C after 72 hours due to an increase in product temperature on the 2nd to 3rd day of fermentation. The saccharogenic power was the highest in Nuruk, a mixture of Baromi2 and Samgwang at 70:30, and the proteinase activity was the highest in 100% Nuruk of Baromi2 but showed a level similar to that of commercial Nuruk. α-amylase and β-amylase activity were the highest in commercial Nuruk, and amyloglucosidase activity was excellent in the 50:50 mixed group. The pH showed a low value at the beginning of fermentation and then gradually stabilized in the weak acidity range, and the total acidity was about 1.00, showing no significant change during the fermentation period. As for the microbial community of Nuruk using Baromi2, Saccharomycopsis fibuligera showed a high dominance rate, while Rhizopus microsporu, Rhizopus arrhizus, and Aspergillus tubingensis also showed a high dominance rate. By combining these results, Nuruk obtained by mixing the separated Baromi2 and Samgwang at 70:30 was selected as the optimal Nuruk.
Fermented liquor was prepared with Samgwang and Baromi2 using the selected Baromi2 Nuruk. After a rapid increase in product temperature and alcohol content in the early stages of fermentation, there was a tendency to stabilize during and late fermentation. In both samples, the sugar content decreased at the beginning of fermentation and then increased again in the second half, finally showing a similar level, and the Baromi2 fermented liquor maintained a relatively high acidity compared to the Samgwang fermented liquor. As a result of organic acid analysis, citric acid, malic acid, succinic acid, acetic acid, and lactic acid were detected, especially in the Baromi2 fermented liquor, the content of citric acid continuously increased during the fermentation period. As a result of the analysis of volatile fragrance components, a total of 16 fragrance components, including 5 alcohols, 10 esters, and 1 acid, were detected in the Samgwang fermenter, and a total of 14 types were identified in the Baromi2 fermenter, including 5 alcohols and 9 esters. During fermentation and aging, the content of ethanol continued to increase, 1-propanol and acetic acid were detected, and ethyl palmitate showed high values in the early stages of fermentation and then decreased significantly during the aging process. On the other hand, the Baromi2 fermenter showed a slight decrease in ethanol content and a partial increase in isobutyl alcohol, and some ester components, including ethyl palmitate, tended to be relatively stable or increase even after aging. As a result of sensory evaluation, the Samgwang fermenter showed a relatively high preference compared to the Baromi2 fermenter in terms of color, sweetness, sourness, complex taste, and body texture, and the overall preference was also high. However, the preference of both fermenters was above average, and no significant difference was found between the fermenters.
Through this study, the highest saccharogenic power was found in Nuruk, which was a mixture of 70 % Baromi2 and 30 % Samgwang, and various microbial communities were stably distributed, showing excellent characteristics throughout fermentation, such as sugar metabolism, organic acid production, and fragrance component formation. When preparing a fermented liquor, there were some differences in the quality characteristics depending on the raw material, but similar trends were confirmed in sugar decomposition and organic acid and fragrance composition, suggesting the possibility of replacing the raw material of Baromi2. As a result of sensory evaluation, the Samgwang fermented liquor showed a relatively high preference, but the Baromi2 fermented liquor also showed more than normal preference, confirming the stability of the sensory quality. Through this, Baromi2 is considered to have sufficient applicability and application potential as a raw material for brewing fermented liquor that can replace ordinary rice.