Studies On The Extraction Using Enzyme And Application Of Rice Proteins

This assay is to systematically do some researches on the process of the abstraction of protein using enzyme, protein function, nutrition and enzymatic modification. Indica rice with poor character is used as the raw material. The aim is to prepare high purified rice protein by enzyme, improve the functional character and then exploit a rice protein product. It provides gist and technological bases for the further development and utilization of rice resources. The main results are as follows:The six enzymes from animals, plants and microbe which have already been commercial at the nowadays stage in China are used to abstract the rice protein. The results demonstrate microbe enzyme has the strengths of high activity, low price, and industrialized ability. It has wide applying foreground. Results of best technics by Alcalase are as follows:temperature:55℃,pH value:8.0,the material-liquid ratio:8:1,enzyme/substract:0.8%,the time:4h with the 30min ultrasonic help. The ratio of abstraction can reach 82.50%, and the purification can reach 66.53%. So it can get the aim of concentrating protein.To get the high purified rice protein by wiping off nearly 80% starch from raw materials, the effect of thermo-stableα-amylase,glucoamylase,wash and carbohydrases to the purification of rice protein were systematically researched. The final technics were:(1)thermo-stableα-amylase 90℃,pH 6.2~6.3,the amount of enzyme 15μ/g rice powder,0.2% calcium chloride,the material-liquid ratio 9:1,time 1h. Then the temperature was decreased to 55℃,the pH was altered to 4.5,glucoamylase was added with the amount of 25μ/g rice powder for 2h.Then enzyme was inactivated, and the liquid was centrifuged.(2)depositions were washed by water at 50℃,and at the ratio of 5 to 1 of material to liquid ,and churned up with water washing once in 1 hour.(3)centrifugal deposited after water washing, and Cellulase and Viscozyme were used for 2h,with the amount of enzyme of 0.5%,0.2% respectively at 50℃,and pH4.5. The purification degree of rice protein can reach 82.73%,which is similar to rice protein isolates.The influences of pH and temperature on rice protein functional property such as solubility,emulsification,foaming activity were studied. The partial functional properties of three kinds of rice protein by different preparation ways were compared. They provide the gist for the development and application of rice protein. And enzymatic modification of rice protein were studied. The conditions by using enzyme were protein concentration :10%, choosing Alcalase, addition of enzyme(E/S)0.4%,hydrolyzing condition at 55℃, pH8.0 for 90 minutes. So at the condition of 7% DH, the functional properties of hydrolyzed rice protein are idealest. On the bases of researches on rice protein properties and modification, the rice protein and whey protein powder were mixed at the ratio of 65 to 35 according the rule of...