Quality Characteristics of Brown Rice Makgeolli Produced under Differing Conditions

Abstract

In this study we investigated the possibility of preparing brewed brown rice makgeolli, a traditional Korean rice wine, under diverse conditions. For this purpose the physicochemical characteristics of makgeolli brewed at different temperatures, utilizing a variety of nuruks, the traditional Korean fermentation agent, were studied. The alcohol content was seen to be highest when brewing occurred at , with the nuruk TN producing 16.2%. At TN produced 14.1% alcohol content. The alcohol content was therefore higher, by about 2%, for fermentations than fermentations. Similarly, saccharifying activity was influenced by temperature and sugar content, with a higher activity seen at than at . As the fermentations progressed acidification petered out, with titratable acidity being 0.50-0.67% in all end samples. On the Hunter L, a, b scale; the a value decreased slightly, while the b value increased steadily during the fermentation process. Measurements of total organic acids were highest at , with the nuruk AK, at about 550 mg%. The content of citric acid was the highest at , being 230-310 mg% in all samples. However, more lactic acid was detected at than at . Total free amino acid was highest at , with TN at , AK at , and RJ at . Total free amino acid and essential amino acid was shown to be higher at than at . The bioactive substance -aminobutyric acid was also higher at , with TN at . From all of these results, we surmise that brown rice makgeolli manufacturing conditions are optimal at fermentation temperatures and using the nuruk TN for brewing vinegar. In addition, the nuruk used clearly affects the quality of brown rice makgeolli and an appropriate method to determine the best nuruk for various purposes should be pursued.