Study On Extraction And Modification Of Chickpea Starch

Chickpea(Cicer arietinum L.)is a legume plant,which has high nutritional value and health care function.,among which starch as one of the main carbohydrates of chickpea,has a low degree of development and utilization.At present,the research on chickpea starch at home and abroad mainly focuses on its physical and chemical properties and functional characteristics,while the research on modification of chickpea starch is less.Therefore,taking chickpea as the research object,this paper determined the best extraction technology of chickpea starch,and determined its main components.Through physical(wet-heat)and chemical(acetylation)modification of chickpea starch,the changes of physicochemical properties and in vitro digestibility of chickpea starch after modification were studied.The main results are as follows:(1)The concentration of NaOH was 0.3%,the ratio of material to liquid was 1:4(w/v),and the extraction time was 240 min.Under these conditions,the extraction rate of chickpea starch was 83.23%,and the purity was 86.52± 0.46%.The extraction method was feasible,and the water content was 8.25±0.27%.In the normal range of starch storage,the amylose content was 37.20±0.20%.(2)After the chickpea starch was treated with damp heat,it was found that the surface of the starch granules was severely dented and damaged.The crystalline form of chickpea starch has not changed,and it is still C-type structure,but its relative crystallinity is reduced,with the lowest being 19.59%.The absorption peak position of the infrared spectrum has not changed obviously,and no new functional groups have been found.With the increase of moisture content in hot and humid treatment,the amylose content of chickpea starch increased to 39.33%.The gelatinization temperature increased from 75.8? to 90.55?,indicating that its thermal stability was enhanced.However,the solubility,swelling power,transparency,freeze-thaw stability,viscosity characteristics,texture characteristics and fast digestible starch content of chickpea starch decreased with the increase of moisture content in hot and humid treatment.The content of slow-digestible starch and resistant starch increased to 16.29% and 14.32% respectively,which indicated that its anti-digestibility was strengthened,which was beneficial to people with hypertension and diabetes.Correlation analysis showed that different moisture contents in moist heat treatment were positively correlated with amylose content and water-separating rate,and negatively correlated with solubility,swelling power,peak viscosity,final viscosity,retrogradation value,hardness,adhesiveness and chewiness.(3)After acetylation of chickpea starch,the surface part of the starch granules appeared grooves,and when the degree of substitution increased continuously,some granules were agglomerated.The crystalline form of chickpea starch has not changed,and it is still a C-type structure.The solubility,swelling power,transparency and freeze-thaw stability of chickpea starch all showed an upward trend with the increase of substitution degree.The viscosity and gel texture characteristics of chickpea starch decreased with the increase of substitution degree.Fourier transform infrared spectroscopy showed that acetylated starch had three new absorption peaks,namely,C=O,C-O,and-CH3,which proved that-COCH3 group was formed in the esterification process,indicating that esterification reaction occurred.Correlation analysis shows that the degree of substitution is positively correlated with the swelling power,transparency and viscosity of starch paste,and negatively correlated with the rate of water separation,peak viscosity,valley viscosity,disintegration value,final viscosity,hardness and adhesiveness.