Research On Production Of Waxy Rice Flour By Aqueous Enzymatic Method And Enzymolysis Process Of Waxy Rice Protein

Waxy rice is the species of viscosity variations from rice and it has high nutritional value. Besides, waxy rice flour is the main raw material for sticky snacks, such as Yuanxiao and rice cakes. At the moment, the production of glutinous rice flour usually adopts the process of grind grain to produce a large amount of waste water. Moreover, waste water contains some water soluble proteins, if it can’t be recycled, not only causes protein waste of resources, but pollutes the environment. The waste water treatment system adopted by companies can increase the processing cost and the burden of enterprises.This study was based on not changing the characteristic of the waxy rice flour as main products, improved the production process of traditional waxy rice flour according to the enzyme technology and makes use of waste water synthetically. This research utilized the enzymolysis technology such as neutral protease to improve the process of waxy rice flour. On the basis of one-factor test, a quadratic regression equation was built by using the method of response surface analysis with SAS data analysis software. The optimum enzymolysis conditions was obtained. This new process improved protein contents in the waste water and studied amino acid composition from waxy rice protein by enzymatic hydrolysis. Through these methods, the waste water could be recovered directly for the by-product development. The development of a new type of waxy rice beverage by using enzymolysis liquid had a certain practical significance. Specific research contents were as follows:1. With waxy rice protein extraction rate as investigation target, the neutral protease enzyme was chosen to use for extraction. It was advantageous to improve the glutinous rice protein dissolution and increase the destruction of the reaction conditions on the glutinous rice starch. This research selected bath mixing method as extraction method and gets the optimal enzymatic hydrolysis conditions through single factor experiment: hydrolysis time was4h,liquid ratio was1:10,hydrolysis temperature was50℃,enzyme dosage was5000U/g, and the actual measured protein extraction rate was about68%.2. Using SAS9.2software for data processing, the mathematical model of the effects of the protein extracting rate from waxy rice on hydrolysis time, liquid ratio, hydrolysis temperature, enzyme dosage was built based on the single factor test of enzyme hydrolysis. The fit of the model was better through the variance and reliability analysis. The optimal enzymatic hydrolysis conditions were as follows:enzyme dosage was4000U/g, liquid ratio was1:9, hydrolysis temperature was40℃, hydrolysis time was4.5h, and the actual measured protein extraction rate was78.75%. Verification test showed that protein extraction rate model could completely neutral protease enzymolysis process of rice protein.3.The waxy rice flour prepared by the optimal enzymatic hydrolysis conditions kept the traditional texture properties of glutinous rice flour, the curves of its firmness, consistency, cohesiveness and index of viscosity identified with traditional waxy rice flour. It showed that waxy rice flour prepared by this process can satisfy traditional foods’ demands for texture properties.4. Based on the amino acid composition analysis of waxy rice enzymatic hydrolysate under the optimal enzymatic hydrolysis conditions, waxy rice enzymatic hydrolysate contained17kinds of amino acids (Asp, Thr, Ser, Glu, Gly, Ala, Cys, Val, Met, Ile, Leu, Tyr, Phe, Lys, His, Arg, Pro), including7kinds of essential amino acids and10kinds of non-essential amino acids and the content of essential amino acids which were not able to be made by body is50.36%. Waxy rice enzymatic hydrolysate has high nutritional value and can be developed as beverages and other products.5.The best formulas for glutinous rice beverage were as follows:enzymatic hydrolysate was900mL, sugar was30g, non-dairy powder was10g, maltodextrin was60g, casein protein was4.5g, glycerol monostearate was1g, purer sucrose esters was0.5g, alginate sodium was0.3g, xanthangum was0.05g, above all of these mixtured1000mL at around70℃. Homogeneous conditions were that the first stage pressure was25MPa, the second stage pressure was40MPa.6. The related properties of waxy rice milk beverage after homogeneous-filling-sterilization has been analyzed:protein content was3.85%to suit the requirements of containing milk beverage sanitary standard of1%; presents the yellowish, glossy, a typical rice fragrance, diverse flavors, no bad smell, soft flavor, flow of the liquid, no precipitation and suspended solids; the average particle size of402.4nm, quality of a material is uniform, and has a good health care function.