가수량에 따른 누룩의 발효기간별 품질 특성

Abstract

To investigate the effects of water contents on the characteristics of Nuruk, three sets of Nuruks were prepared with water contents of 20%, 26%, and 30%. Morphological shapes, internal temperature, physicochemical properties, enzyme activity, metabolites, and volatile chemical patterns were monitored for 30 days. Regardless of the water content, the morphological shapes showed that the mold mycelia were extended to the inside and the weight and size were decreased in the three Nuruks. The internal temperature was the highest (39.7℃) for a water content of 26%. Higher water contents were accompanied by lower pH. α-Amylase activity was increased 1.5-fold in Nuruk containing 30% water. Acidic protease activity was also the highest (1,800 U/g) after 20 days for Nuruk with 30% water content. In addition, the levels of saccharides (glucose, galactose, and fructose) were increased 2.4-, 1.97-, 1.5-fold, respectively, with higher water contents. Organic acid (lactic acid) content was the highest (2.2 mM) in Nuruk containing 30% water. Free amino acid (glutamate and proline) contents in Nuruk with 26% and 30% water contents were higher than those in the 20%. The volatile patterns were different in the three Nuruks with 20%, 26% and 30% water contents. This study suggests that the range of water content of 26-30% might be appropriate for the production of Nuruk with high saccharification and proteolytic activities.