Study On The Preparation Of Starch Sugar,Rice Protein And Rice Peptide By Enzyme-linked Microfiltration From Broken Rice And Its Optimization

10% to 15% of broken rice will be produced during milling of rice.Broken rice has similar composition with the whole rice but it has lower value than the whole rice.Therefore,it is always the task for the industry researchers to efficiently develop and utilize broken rice.In this study,the technology of enzyme-linked microfiltration was put forward to extract the starch,rice protein and rice peptide in the broken rice.Firstly,the broken rice was enzymolyzed by amylase and the starch syrup was separated by microfiltration with DE value 26-28 as the index.On this basis,orthogonal experiment was designed to optimize the process parameters.Then,the intercepted fluid of the first enzymatic hydrolysis was enzymolyzed by saccharifying enzyme and the starch syrup was separated by microfiltration with DE value 38-40 as the index.On this basis,orthogonal experiment was designed to optimize the process parameter.Then,the intercepted fluid of the second enzymatic hydrolysis was enzymolyzed by protease and the rice peptides was separated by microfiltration with DH value as the index.On this basis,Response surface test was designed to optimize the process parameter.Next,the technology of enzyme-linked microfiltration for the product of starch sugar,rice protein and rice peptide was amplified.Finally,the biological activity of rice peptide was studied.The main research results are as follows:(1)Enzymatic hydrolysis process optimization with DE value 26-28: in order to obtain starch syrup with DE value 26%-28%,Suhong AA Plus 2X,a high-temperature resistant amylase,was used to optimize the process of the broken rice after milled by grain mud ink,including solid-liquid ratio,particle size,hydrolysis temperature,enzymatic hydrolysis time,enzymatic dosage and p H.On the basis of single factor experiment,orthogonal experiment was designed.The optimized conditions were as follows: the ratio of solid-liquid 1:20,grinding 3 times,hydrolysis temperature 75?,hydrolysis time 40 min,enzymatic dosage 0.5‰,p H6.3.(2)Enzymatic hydrolysis process optimization with DE value 37-40: in order to obtain starch syrup with DE value 37%-40%,Suhong? GA III 2X,a saccharifying enzyme,was used to optimize the process to rice after a single enzymatic,including enzymatic hydrolysis temperature,hydrolysis time,enzymatic dosage and p H.On the basis of single factor experiment,orthogonal experiment was designed.The optimized conditions for single factor optimization were as follows:hydrolysis temperature 65?,hydrolysis time 30 min,enzymatic dosage 0.375‰,p H4.3.(3)The optimization with DH value: the process of enzymatic hydrolysis was optimized,including enzymatic types,hydrolysis temperature,enzymatic hydrolysis time,enzymatic dosage and p H.On the basis of single factor experiment,response surface experiment was designed in order to obtain rice peptide with high proteolysis degree.The best conditions is: alkaline protease,enzymatic hydrolysis temperature 58.4?,hydrolysis time 6.9 h,enzymatic dosage 0.29%.The results of response surface optimization were as follows: enzymatic temperature 58.4?,enzymatic hydrolysis time 6.9 h and enzyme dosage 0.29%,and the hydrolysis degree was 44.97%.(4)Amplification experiment: the optimized conditions were magnified and the conditions of obtaining DE value of 26%-28% starch sugar as follows:solid-liquid ratio of 1:20,hydrolysis temperature 75?,enzymatic hydrolysis time 50 min,enzyme dosage 0.5‰,p H6.3.The conditions of obtaining DE value of37%-40% starch sugar were as follows: hydrolysis temperature 65?,enzymatic hydrolysis time 50 min,enzyme dosage for 0.25‰,p H4.3.The conditions of obtaining rice peptide with high degree of proteolysis were as follows: alkaline protease,hydrolysis temperature 60?,hydrolysis time 6 h,enzymatic dosage 0.25%,and the degree of hydrolysis was 41.8%.(5)Biological activity of rice peptide: the liver protection activity of rice peptide was studied.The results showed that rice peptides at low dose(RPL)and high dose(RPH)all could reduce the levelss of ALT,AST,LDH.Furthermore,the groups RPL and RPH also could reduce the contents of TNF-?,IL-1?,IL-6,MDA,and increased the contents of SOD and GST in serum.The results of HE staining showed that the RPL group and the RPH group had less balloon-like liver damage and injury area than the model group.These results indicated that rice peptide had certain hepatoprotective effects,and activities of anti-inflammatory and anti-oxidation.