The Effect Of Extrusion And Enzymatic Hydrolysis On Structure Of Zein And The Antioxidation Activity Of Corn Gluten Meal Hydrolysates

Corn gluten meal (CGM) is a major by-product of corn wet milling,it is very importantfor industry to further processing CGM.In this paper,CGM was pretreated by puffing,enzymatic hydrolysis and microbial fermentation,then extract and purify the zein from thepretreated CGM,and then investigate the surface morphology by SEM andAFM.Furthermore,we evaluated the antioxidant activity of the enzymatic hydrolysis of corngluten meal by a variety of in vitro experimental methods and animal experiment.In thispaper,the projects have been investigated as follow:Corn gluten meal (CGM) as raw material,puffing, enzymatic hydrolysis and microbialfermentation,different conditions,extract zein,and different conditions of gliadin were isolatedand purified,and then to study the surface morphology, using a variety of in vitroexperimental methods and animal experimental evaluation of the antioxidant activity of theenzymatic hydrolysis of corn gluten meal, for scientific and rational development of deepprocessing of corn gluten meal to provide a theoretical basis.The main content of the paper isas follows:1.We extracted the zein under different conditions,including unprocessing,puffing,puffing-protease enzymatic hydrolysis,puffing-alkaline enzymatic hydrolysis and puffing withBacillus natto fermentation.And then flask fermentation the beans bacteria by expandingtreatment of corn gluten meal,select a good strain.The fermentation time was4hours,whichwas determined by measuring the culture medium soluble protein content and antioxidantactivity and gel electrophoresis. The optimum liquid culture process conditions of Bacillusnatto fermentation of extruded corn gluten,lastly,conditions for puffing includes initial pH of7.0, temperature at34°C,spinning frequency at200r/min,4hours for fermentation processand minimum soluble protein content and antioxidative activity of12.74mg/mL and725.71U/mL respectively.2.Gliadin extracted by different methods were used to separate and purify by stepreversed-phase chromatography,and compared the effects of reverse phase column andgradient elution on the separation of zein,the results of reversed phase chromatographyconclude that different extraction method lead to varying degree of changes on the structureof zein.And two-step separation was used to separate gliadin, firstly pigments and someimpurities were removed by the gel column, and then separated it by reversed-phase chromatography,results showed that higher purity gliadin can be separated by electrophoresisanalysis,the molecular weight of zein is distributed in the range of20.1KDa-31.0Kda.3.The surface morphology of gliadin proteins were investigated by scanning electronmicroscopy(SEM)and atomic force microscopy(AFM).SEM imaging figures showed thatpretreated corn gluten meal have a significant effects on the the surface structure of theextracted gliadin.Puffying treatment can cause a looser state of zein;the enzymolysis make thegliadin spherical,in a constant time,the longer the hydrolysis time,the rounder of the structureof the zein,and the large sphere is very easy to be hydrolyzed into a smallsphere.Moreover,we can conclude the influence of pretreatment on the surface structure ofzein by the results of AFM,furthermore we can also concluded the forming process of zein toa mold.4.The results of vitro and in vivo indicated that the corn gluten meal contain someantioxidant activity,and pre-treatment with enzyme can enhance the in vitro antioxidantactivity,DPPH radical scavenging rate of67.68%.The results of animal experiments alsoshowed that the hydrolysis of corn peptide has a strong antioxidant activity,which cansignificantly increased the activity of SOD and GSH-Px activity of plasma and liver ofmice,and significantly reduced MAD concentration. Therefore,these results showed that cornpeptide is an excellent anti-oxidant.