Studys On The Preparation Of Low Protein Rice By Enzyme-bacteria Combination Process

The incidence of chronic disease is increasing year by year in the whole world,long-term persist in low-protein diet can effectively control the deterioration of kidney disease.Rice is the staple food of most people in China,which protein belongs to plant protein with low nutritional value.If kidney disease patients intake too much protein like this,it will increase the burden of kidney,reduce the intake of high-quality animal protein as well as affect the nutritional balance and diversity of the body.Therefore,the development of low protein rice is of great significance for the supply of staple food for nephrotic patients.In this paper,the whole rice was treated with Lactobacillus and protease,and the effect of different Lactobacillus and protease on the deproteinization of the whole rice was studied.Combined with univariate test,Plackett-Burman design and Box-Behnken Design,the optimal technology of Lactobacillus and protease was designed,and the technology of low protein rice of both parties combined was studied.The main results are as follows:1.Univariate test and response surface optimization process were used to optimize the degradation process of rice protein by Lactobacillus.It was determined that 20%malic acid was the suitable pretreatment acid solution,the suitable rice was October rice field,and the suitable fermentation strain was Lactobacillus plantarum?L.plantarum SP-1?.The optimum conditions of rice protein degradated by Lactobacillus plantarum were:temperature 37?,solid-liquid ratio 1:2,p H value 6.5,fermentation time 18 h,bacterial age 18 h,viable bacterial number 7.37×10¹⁰CFU,at this time,rice protein degradation rate was 30.35±1.52%.2.Univariate test,PB factorial analysis and response surface optimization process were used to optimize the enzymatic hydrolysis of rice protein.The compound protease I was determined to be the suitable protease.The optimum conditions of rice protein degradated by compound protease I were as follows:temperature 55?,solid-liquid ratio 1:3,enzyme dosage 5%,p H 6.5,enzymolysis time 18 h,and rice protein degradation rate was 57.04±1.35%.3 The optimal technology of low protein rice production by enzyme-bacteria combined is:first,the enzyme hydrolysis is carried out under the optimal condition of compound protease I,then the rice is washed with sterile water,finally continue to ferment under the optimal condition of Lactobacillus plantarum,which protein reduction rate is81.24±2.73%.Scanning electron microscope showed that after different treated methods,the composite starch granules of rice were decomposed,and there were pits and small holes on the surface,which made the close binding between rice and protein loose.The order of the degree of structural looseness of the six treatments was:enzyme treatment after bacteria treatment>enzyme treatment>bacteria treatment after enzyme treatment>bacteria treatment>enzyme bacteria treatment at the same time>acid treatment.Combining with the electrophoretic analysis of the treated samples and the culture medium,we can infer that there are two ways to dissolve the protein:one is to remove protein molecules directly from rice,the other is to decompose protein into small protein molecules or peptide,in which compound protease I mainly degrades glutenin,globulin and prolamin,while Lactobacillus plantarum mainly degrades glutenin and prolamin;It can inhibit each other and weaken the deproteinization when Lactobacillus plantarum and compound protease I are used at the same time;malic acid solution can wash off a small amount of protein,such as glutelin.By comparing the sensory evaluation of direct drying method and direct steaming to make instant rice method,it was determined that the suitable way of preservation was direct steaming to make the instant rice and refrigerate it after vacuum packaging.