The Optimization Of Preparation Conditions Of Buckwheat Microporous Starch And Improvement Of Its Absorption Properties

Starch is the main composition of buckwheat grains. Compared with other grain starchy feeds, buckwheat starch has the features of higher peak viscosity, heat viscosity and ultimate cold viscosity, lower aging rate and lower gel dehydration contractility as well as good freeze-thaw stability, etc., which is a new starch resource. To grasp the preparation condition of microporous starch and its absorption ability, with buckwheat starch used as material, the research is to systematically analyze the factors which affect the formation of buckwheat microporous starch, to optimize the technological condition for preparation of buckwheat microporous starch using acid and enzyme, and to illustrate the influence of crosslinking treatment on the absorption property performance of buckwheat microporous starch. The main research results are as follows:(1) Under the condition of acid hydrolysis, with the increasing dosage of hydrochloric acid and the extension of reaction time, the hydrolytic rate of buckwheat starch appeared a tendency of leap increase. The buckwheat microporous starch had a strong absorption ability on carmine within the hydrolysis rate of the range of 2.0%-8.0%, less than 1.0% or too high is not propitious to the absorption on carmine. The production technological parameter of the method of using acid to prepare buckwheat microporous starch is of 12% hydrochloride concentration, hydrolyzed for 6 h at the temperature of 50℃, with its hydrolysis rate 3.0%-5.0%.(2) According to the comparison of the action effect ofα-amylase, fungusα-amylase, pullulanase enzyme and compound enzyme ofα-amylase and fungusα-amylase on buckwheat starch, the fungusα-amylase has a higher enzyme activity and has a better treatment effect on buckwheat starch, and the buckwheat microporous starch prepared by fungusα-amylase has a higher water and oil absorption rate as well as a lower stacking density, etc.. The buckwheat microporous starch has a higher water and oil absorption rate and a lower stacking density under the preparation condition of reaction temperature of 40℃, pH value 6.2, reaction time 14 h, fungusα-amylase dosage of 2%.(3) By crosslinking treatment on buckwheat microporous starch with epichlorhydrin (ECH), the order of the factors affecting water absorption rate is crosslinking temperature, pH value, reaction time and crosslinking agent dosage, the order of factors affecting oil absorption rate is crosslinking agent dosage, pH value, crosslinking temperature, reaction time. The suitable condition to prepare buckwheat crosslinking microporous starch is the reaction temperature of 55℃, pH value 9, reaction time 180 min, crosslinking agent dosage of 4 mL. Crosslinking treatment makes the water and oil absorption rate of buckwheat starch increase by 34.69 % and 12.56 % respectively, moderate crosslinking treatment is benefit to improve the absorption ability of buckwheat microporous starch. With buckwheat starch used as material, through the technology of using enzyme and crosslinking treatment, the buckwheat microporous starch has good absorption ability.