Enzyme Modification Of Yeast β-glucan And Its Application

Yeast β-glucan is an important new resource food,but its water-insoluble nature limits its use in food.In this paper,the physical and chemical properties and structure of oatβ-glucan and yeast P-glucan were compared.Yeast beta-glucan is hydrolyzed to increase the solubility.The enzymatic hydrolysis process was optimized and the product was analyzed and used in the pieces of sugar.The following is the main conclusions of this paper.Based on the determination of the solubility,structure and physicochemical properties of yeast β-glucan and oat β-glucan that the yeast β-glucan’s total sugar was 71.08%,the protein content was 10.09%,the fat content was 0.15%and the water content was 1.33%.The oat β-glucan’s total sugar was 81.35%,the protein content was 2.31%,the fat content was 0.29%and the water content was 6.41%.The solubility of yeast β-glucan was 3.13%by freeze-drying method.And the solubility of yeast β-glucan was 79.89%by oven drying.The enzymatic hydrolysis of yeast β-glucan was optimized by single factor experiment and response surface experiment.The results showed that the optimum conditions for the enzymatic hydrolysis of yeast P-glucan were 1.14 g/100 mL,the concentration of enzyme was 0.16 U/mL,the temperature was 44 ℃ and the pH was 4.20.Under this condition,the yield of water-soluble yeast β-glucan was 39.89%.The effect of time on the yield of water-soluble yeast β-glucan showed that the optimum enzymolysis time was 1.5 h.Through the determination of the triple helix structure of yeast β-glucan before and after enzymatic hydrolysis,it was concluded that the content of yeast β-glucan with the triple helix structure in the yeast β-glucan sample was 18.42%.The content of yeast P-glucan with the triple helix structure in the water-soluble yeast β-glucan sample was 15.55%.Through the thermogravimetric analysis of yeast β-glucan before and after enzymatic hydrolysis,it was showed that the first weight loss peak of yeast β-glucan appeared at about 50 ℃,the weight loss rate was 5.58%,the characteristic decomposition temperature was 360 ℃,the weight loss rate was 94%,and the decomposition temperature was 780 ℃.And the first weight loss peak of yeast β-glucan after enzymatic hydrolysis also appeared at about 50 ℃,the weight loss rate was 6.47%and the characteristic decomposition temperature was 356 ℃.At this time,the mass loss rate was 88%,the decomposition temperature was 740 ℃.Based on the infrared analysis of yeast β-glucan yeast β-glucan before and after enzymatic hydrolysis,it was found that the glycoside bond type of yeast β-glucan before and after enzymatic hydrolysis,even β-1,3 glycosidic bond.The ratio of stevia inulin,aspartame and water-soluble yeast β-glucan was determined by sensory scoring.The results showed that the best ratio was aspartame:stevia inulin:soluble yeast β-glucan 0.4:0.4:5.0.Optimization of the process of the pieces of sugar by single factor experiment and three-factor three-level orthogonal experiment and sensory score method.The results showed that the optimum conditions were the gelatin addition 4%,glycerol addition 25%,pH 4.0,and the normalized sensory score was 0.64 under this condition.By studying the effect of temperature,humidity and time on the storage of the sample,the following conclusions were obtained:With the increase of storage temperature,the tensile strength of the sample and the blank control group increased gradually,and the elongation at break increased.As the storage humidity increases,the tensile strength of the sample and the blank control sample decreases significantly and the elongation at break increases.With the increasing storage time,the tensile strength of the sample and the blank control group were both increase and the elongation at break decrease.