Research Of α-amylase Preparation In Soy Sauce Koji And Fermentation Process

The market of soy sauce is typical of "small product, big market". The annual output ofsoy sauce in China is more than600million tons, more than60%of the world’s annualproduction, but it is still a large gap with Japanese products in quality. It will become the mainproduction mode of high quality, high-grade soy sauce with the technology of high salt dilutedcombined with fermentation metabolic regulation, which had less relevant research, especiallyabout koji metabolic regulation.By the method of adding α-amylase in koji-making, it hadresearched the effects of koji and flavor of soy sauce as well as other physicochemicalproperties. The final method was applied to industrial production which provided certainguiding significance and methods for the improvement of quality of soy sauce andfermentation metabolic regulation.Koji enzyme activity, dry matter loss, spores and the total number of bacteria and otherfactors in koji-making with adding α-amylase were studied. The results showed that theaddition of α-amylase in koji-making could reduce dry matter loss, spores and the totalnumber of bacteria by20.12%,14.57%,22.28%.The acidic protease, amylase activity,carboxypeptidase activity were increased by14.55%,35.02%,13.89%with little effect of theneutral, alkaline protease and reduce of activity of leucine aminopeptidase and cellulase.Physical and chemical properties of the moromi were studied. Results showed that theaddition of α-amylase in koji-making could increase contents of reducing sugar of the soysauce in70days when the reducing sugar contents were2.45g/100mL with an improvementof11.36%. The red index and yellow index of the soy sauce were also increased and in70days experimental group had red index and yellow index of3.30,8.20, with control group3.00,7.60, which respectively raised10.00%and7.89%. More importantly, the utilizationrate of protein and soy production rate were increased by2.75%,4.18%in experimentalgroup.The effects of physicochemical properties by the addition of α-amylase in fermentationunder industrial conditions were researched at the same time with glycos-esterifiablemonascus in koji-making with Aspergillus oryzae.The results showed that the addition of αα-amylase in fermentation process could improve the contents of reducing sugar and solublesalt solids.Besides, mixed koji could improve the quality of high salt diluted soy sauce.