청국장 제조시 기호성 개선과 생리활성 증진의 목적으로 흑마늘을 첨가한 청국장의 항산화 활성과 구성 및 유리 아미노산의 변화를 대조구와 비교 검토하였다. 총 폴리페놀 화합물은 흑마늘 첨가 청국장의 물추출물(BWE)에서 7.03 mg/100 g으로 가장 높았으며, 일반청국장의 물추출물(CWE) 3.64 mg/100 g, 흑마늘 첨가 청국장의 에탄올 추출물(BEE) 2.88 mg/100 g, 그리고 일반 청국장의 에탄올 추출물(CEE)가 0.81 mg/100 g 순 이었다. 전자공여능은 BWE가 91.83%로 가장 높았으며, BEE(37.35%), CWE(25.54%), CEE(14.80%) 순이었다. SOD 유사활성은 BWE가 20.20%로 가장 높았으며, BEE(9.22%), CWE(7.91%), CEE(6.45%) 순이었다. 지질산패억제능(TBARS)을 측정한 결과는 BWE 35.18%으로 가장 높은 활성을 나타내었으며, BEE(28.33%), CWE(17.40%), CEE(14.93%) 순이었다. 일반청국장이 흑마늘 첨가 청국장보다 총 아미노산의 함량이 높았으나 필수아미노산의 비율은 흑마늘 첨가 청국장(43.18%)과 일반청국장(42.27%)에서 뚜렷한 차이를 보이지 않았다. 유리아미노산은 일반 청국장에서는 총 27종, 흑마늘 첨가 청국장에서는 총 23종이 검출되었다. 일반청국장의 유리아미노산은 L-lysin(9.23%)이 가장 높았고, 흑마늘 첨가 청국장의 유리 아미노산 함량은 L-phenylalanine (23.14%)이 가장 높았다. 일반청국장에 함유되어 있는 유리아미노산 중 L-threonine, L-serine, L-sarcosine, L-proline, L-alanine, L-valine, D,L-${eta}$-aminoisobutyric acid는 흑마늘 첨가 청국장에서는 검출되지 않았다.
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-${eta}$-aminoisobutyric acid) were found in CC but not in CCWB. The ${gamma}$-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.
