Study On Analysis Of The Amylose Content In Corn Starch

The purity of starch has a significant influence on its various physicochemical propertise and application,so it is important to improve its purity.This article mainly uses single-wavelength spectrophotometry,dual-wavelength spectrophotometry and gel chromatography to determine amylose and amylopectin content in corn starch.The detection range and applicability of different corn starch of three ways were obtained.The major conclusions were as follows.The corn starch was precipitated multiple times by n-butanol precipitation to obtain the crude amylose and amylopectin,then we purify amylose and amylopection by high-pressure column chromatography system.The blue value and iodine affinities of crude amylose were 0.93 and 19.26% respectively.The blue value and iodine affinities of crude amylopectin were 0.20 and 0.35%,respectively.The blue value and iodine affinity of purified amylose were 1.06 and 19.36%,respectively.The blue value and iodine affinity of the amylopection were 0.93 and 0.41%,respectively.The purity of the extracted amylose was 97.14%,and the purity of amylopectin was98.21%.When analyzing amylose used gel chromatography,the best pretreatment conditions for waxy corn starch were adding urea and boiling for 20 minutes.The optimal conditions for the pretreatment of high amylose corn starch and common corn starch were boiling water bath for 10 minutes.When amylose was analyzed by dual-wavelength spectrophotometry,the optimal conditions for the pretreatment of high amylose corn starch and waxy corn starch were high amylose corn starch was heated at 130? for 25 min.The optimal conditions for the pretreatment of waxy corn starch was heated at 115? for 25 min.The valid range of amylose content determinated by single-wavelength spectrophotometry ranged from 0% to 85%.It was suitable to determinate amylose content of corn starch.The valid range of amylose content and amylopection content determined by the dual-wavelength spectrophotometry ranged from 0% to 85% and45% to 100%,respectively.It was suitable to determinate amylose content of waxycorn starch and high amylose corn.The valid range of amylose content and amylopection content determinated by gel chromatography ranged from 0% to 85%;and 6% to 85%,respectively.And gel chromatography was suitable to determinate amylose content.The amylose contents in five samples of waxy corn starch,normal corn starch 1,normal corn starch 2,normal corn starch 3,and high amylose corn starch were determined by three different analytical methods.The results of single wavelength spectrophotometry were 7.488%,31.882%,31.139%,32.220%,70.731% respectively,the results of dual-wavelength spectrophotometry were 5.109%,28.707%,27.937%,27.032%,68.630%,and the results of gel chromatography were 2.906%,29.419%,30.288%,28.958% and 81.075%,respectively.