The Change Of The Biological Acyivity Ingredient During The Fermentation Of Low-NaCl Soy Food

Eastern Cheese was one kind of new fermented soy food. It was baked after the fermentation of mucor. It had a lot of merits, such as its short fermentation period, low-NaCl, good plasticity contour and so on. In the fermentative process of Eastern Cheese, the change of biological activity ingredient was studied in this article.First, the isoflavone extraction condition was optimized, the determination method of isoflavone content—the method of three wavelengths of two samples was determined, the determination condition of HPLC was optimized to determine the content and composition of isoflavone. In the fermentative process of Eastern Cheese, the change of the content and composition of isoflavone was studied. The result indicated: The content of isoflavone dropped from 34.99μg/mL to 21.73μg/mL, reduced 37.90%. The composition of isoflavone was optimized through the fermentation process, and the biological activity was higher. Aglycone was easy to absorpte in human body , and its biological activity was stronger. The content of aglycone increased from 0.97μg/mL to 18.62μg/mL, enhanced 18.20 times. The percentage of aglycone increased from 2.77% to85.69%, enhanced 29.94 times. And in the fermentative process, the change of the content and composition of isoflavone in 12~24 h period was the most remarkable.Next, the extraction method of soy peptide was determined. In the fermentative process of Eastern Cheese, the change of the content and composition of soy peptide was studied. The result indicated: The content of soy peptide increased from 56.00 mg/g (dry matter) to105.98 mg/g. In 24~48 h period, the enhanced scope was up to 30.28 mg/g, 1.54 times of 0~24 h. In the fermentative process, the molecular weight of soy protein reduced. In 0~24 h period, the maximum molecular weight of soy protein fell from 83.33 kD to 31.27 kD. in 24~48 h period, it fell from 31.27 kD to 26.16 kD. And in the pehtze, the molecular weight of soy peptide distributed continuously. And the content of small-peptide composed by 2~5 amino acids was high, the content of big-peptide which was composed by more than 10 amino acid was low.Finally, the influence of bake on the content and composition of the biological activity ingredient in Eastern Cheese was studied. The result indicated: In the bake process, the content of isoflavone increased from 161.66μg/g (dry matter) to 173.17μg/g. The content of glucoside increased from 23.13μg/g to 37.15μg/g. Corresponding, the content of aglycone reduced from 138.53μg/g to 136.03μg/g. In the bake process, the content of soy peptide increased from 105.98 mg/g to 114.04 mg/g. The composition of soy peptide was optimized through the bake process, in product the percentage of small-peptide composed by 5~7 amino acids increased obviously.