Isolation Of Amylose From Corn And Preparation Of High-amylose Corn Starch Based Films

Starch consists mainly of linear,low branched amylose and highly branched amylopectin.High-amylose corn is a kind of special corn;Because of its high amylose content,the molecular structure and physicochemical properties of it are significantly different from those of normal corn starch.Therefore,there are many special applications in industry,such as the preparation of biodegradable film and the extraction of amylose.However,in China,due to the scarcity of germplasm resources,the research on the breeding of high amylose corn and its starch application and development is still in initial stage.Based on the previous studies,this study used the high amylose corn and normal corn grown by our research group as raw materials.After optimizing the extraction conditions,the effects of different extration methods on the purity and properties of amylose were studied,and an efficient high-purity methodlogy of amyloe extraction was established.On the basis of mentioned above,the effects of different parameters on the preparation and physical properties of high amylose corn starch film was studied.The purpose of this paper is to promote the application of high amylose corn in China.The results of this study are as follows:1.Effects of different methods for the extraction of amylose:1)Improving the amylose content of raw starch was helpful to the improvement of the extraction rate of amylose.2)The extraction methods had significant effects on the extraction rate,purity and structure of amylose.The purity of amylose is negatively related to the extration rate.3)Dimethyl sulfoxide(DMSO)dispersion method and high-rpm precipitation seperation were the most suitable amylose extraction methods for high amylose corn starch.2.Effects of different parameters(gel method,starch concentration,plasticizer)on the properties of high amylose corn starch film:1)The gel method had the most significant effect on transparency,and the high temperature and high pressure method were the best gel methods;2)Starch concentration was of the greatest impact on the thickness,tensile strength,elongation at break and oil solubility of films.The highest thickness and tensile strength were obtained with 10% starch concentration;the highest elongation at break was required for starch concentration of 5%,and the lowest oil solubility was obtained at 2% starch concentration;3)Plasticizer was most important for water solubility,and the effect of xylitol xylitol was better than glycerol.