Study On Physicochemical Properties And Aging Mechanism Of Chestnut Starch

Retrogradation has more adverse effects on the quality of starch food.And it is of great significance to study the mechanism of starch aging in the storage process to ensure the quality of starch food.This paper respectively to three kinds of chestnut starch of 14 species of the genus nuts with different aging time after processing of chestnut starch as the research object.Structural and physicochemical properties of starches were characterized by means of scanning electron microscopy(SEM),X-ray diffraction(XRD),differential scanning calorimeter(DSC),rapid visco analyser(RVA)and the correlation analysis.To explore the related retrogradation mechanism of chestnut starch.The molecular structure of starch after aging and the change rule of resistant starch were analyzed.Through the study on the characteristics of starch of 14 main cultivars of chestnut in north and south China,the differences of the characteristics of different cultivars were analyzed.The amylose content of different samples varied greatly,with a distribution range of 13.9?27.8%.The granule surface is smooth,the granule size of the same starch varies greatly.And all starches are C-type crystals.The starch of 14varieties had good freeze-thaw stability.At 90?,the sample expansion degree is17.55?22.27g/g.The gelation temperature of castanea chinensis starch was lower,the viscosity characteristics vary greatly.After 3h,1d,3d,7d and 14d treatment,the amylose content of the aged chestnut starch increased with the extension of aging time.The aged starch was still lower than the original starch after 14d treatment.After the aging treatment,the chestnut starch was polygonal,the surface was not smooth with slight wrinkles and no obvious shape.The crystal type was still C,and the crystallinity of the aged samples was far lower than that of the original starch.The two crystal peaks of the original starch in C1 region were Cb-type crystalline starch.After aging treatment,there was only one obvious crystal peak in C1 region,and several weak crystal peaks were Ca-type crystalline starch.The results were consistent with those measured by XRD.There was no significant change in the trend of infrared spectrum,and the peak intensity ratio of(1047/1022)cm^-1decreased.During the aging process,the unstable crystalline part of starch was destroyed and the gelation enthalpy decreased.The initial gelation temperature of the aged starch was higher than that of the original starch.The gelatinization temperature of original starch was the highest,while that of aged starch was lower.In the heating process,the maximum value of G?was higher than the maximum value of G??,indicating that the elasticity value of the aged chestnut starch paste was greater than the viscosity value.As the extension of the ageing time?H increases gradually,but 14d?H is still less than the original starch.The RS content of chestnut starch decreased significantly after aging treatment.