반응표면분석을 이용한 청국장 제조시 마늘의 첨가조건 최적화

Abstract

This study was performed to determine the optimal composition of Cheonggukjang added with garlic. The experiment utilized a centralcomposite design (CCD). The evaluation was carried out by means of response surface methodology (RSM), which included 18 experimentalpoints with three independent variables : the content of the garlic (1.3∼9.7%, X1), the steaming time of garlic (0∼15.1 min, X2), and thefermentation time of Cheonggukjang (48.2∼71.8 h, X3). The viscous substance (Y1), acidity (Y2), amino-type nitrogen (Y3), γ-GTP activity (Y4)and ABTS radical scavenging activity (Y5). were assessed in four replicates with five dependent variables. The maximum content of theviscous substance was 13.02% at 6.53% (X1), 6.81 min (X2) and 55.18 h (X3). The acidity was increased when the fermentation time waslonger, and the minimum acidity point was 0.50% at 7.75% (X1), 3.42 min (X2) and 58.60 h (X3), respectively. The content of the amino-typenitrogen at the experimental range studied was was 80.58∼158.82 mg%, and the stationary point was at saddle point. Using ridge analysis,the maximum point was 156.97 mg% at 6.21% (X1), 14.85 min (X2) and 58.04 h(X3). The optimum conditions of γ-GTP activity was 5.73%(X1), 6.99 min (X2) and 57.96 h(X3), respectively, at the maximum point was 353.66 mU/mL. The maximum point of ABTS radical scavengingactivity was 76.43% at 3.78% (X1), 14.28 min (X2) and 57.99 h(X3) at the saddle point, when the garlic steaming time was longer.