However, the amounts of total nitrogen and amino nitrogen were both higher in soy sauce fermented by A. oryzae HG76 than that by A. oryzae HN3042. After the aging period of 31 days, soy sauce fermented by A. oryzae HG76 contained 1.75% total nitrogen and 0.92% amino
nitrogen, while 1.62% and 0.77% was observed in the control of A. oryzae HN3042, which indirectly revealed the excellence of A. oryzae HG76 in proteolytic degradation than A. oryzae HN3042. The increase in amino nitrogen and total nitrogen indicated that soy sauce contained more protein and amino acids, thereby enhancing the soy sauce quality. In this aspect, our research is agreement with the reports by Cao et al. (2010).