흑마늘 첨가에 따른 청국장의 항산화 및 아미노산의 변화

The antioxidant activity and amino acid composition of various Cheonggukjang extracts, such as the water extract from Cheonggukjang (CWE), the alcohol extract from Cheonggukjang (CEE), the water extract from Cheonggukjang with black garlic (BWE) and the alcohol extract from Cheonggukjang with black garlic (BEE), were examined to investigate the effect of black garlic on the sensory quality and functional properties of Cheonggukjang. The total polyphenol contents of various extracts were 7.03 mg/100 g (BWE), 3.64 mg/100 g (CWE), 2.88 mg/100 g (BEE) and 0.81 mg/100 g (CEE). The radical scavenging activity of the DPPH radical was highest in BWE (91.83%), followed by BEE (37.35%), CWE (25.54%) and CEE (14.80%), in that order. The SOD-like activity was highest in BWE (20.20%), followed by BEE (9.22%), CWE (7.91%) and CEE (6.45%). The thiobarbituric acid reactive substances (TBARS) were highest in BWE (35.18%), followed by BEE (28.33%), CWE (17.40%) and CEE ((14.93%). The total amino acid content of Cheonggukjang (CC) was higher than that of Cheonggukjang with black garlic (CCWB), but the essential amino acid content of CCWB (43.18%) was higher than that of CC (42.27%). The 27 kinds of free amino acid were found in CC, but only 23 kinds were found in CCWB. The L-lysine content was highest (9.23%) in CC, and the L-phenylalanine content was highest (23.14%) in CCWB. The free amino acids (L-threonine, L-serine, L-sarcosine, L-proline, L-alanine, L-valine and D,L-β-aminoisobutyric acid) were found in CC but not in CCWB. The γ-amino-n-butyric acid (GABA) was found in CCWB but not in CC. These results suggest that the addition of black garlic has beneficial effects on the functionality of Cheonggukjang without decreasing its sensory characteristics.