연구논문 : 청국장에 대한 ε-Poly-L-lysine 혼합제재의 항 미생물 효과 및 혼합비율의 최적화

The objectives of this study were to evaluate the antimicrobial effects of e-poly-L-lysine mixture (EPM) on cheonggukjang and to determine the optimal mixing ratio in cheonggukjang. Increasing the EPM up to 2% decreased viable cell counts at both 15oC and 30oC storage. The pH of cheonggukjang without EPM increased slowly over the storage periods, but cheonggukjang with EPM showed a slight increasing tendency, with the highest pH at 2% EPM. The sensory scores, such as texture and flavor, were highest in samples containing 2% EPM; however, overall preference was not significantly different when compared to the control. For the optimum cheonggukjang processing conditions, 13 experimental points were selected. Soybean and EPM were chosen as independent variables. Viable cell count, pH, texture, and overall preference were measured. The optimum formulation of cheonggukjang using the numerical analysis was found to be 98.52% soybean and 1.48% EPM, resulting in a 0.722 desirability value.