Aging Characteristics Of Chestnut Starch And Preparation Of Resistant Starch

In foods containing starch,retrogradation of starch is an inevitable process.It will affect the texture of the product and produce stiff mouthfeel,thus reducing the sensory and shelf life of the product.It is very important to understand deeply the mechanism of starch retrogradation and find effective measures to prolong the quality of starch food.In this paper,chestnut starch was taken as the research object,the effects of starch aging,xanthan gum and guar gum with different concentrations on the properties of chestnut starch were studied,and the preparation of resistant starch was optimized:1.Compared with chestnut starch,the reticular structure of aged starch was destroyed.The amylose deposition of the aged starch is smaller than that of the original starch,but increases with the aging time,from 9.06%to 14.30%.Raw starch has the strongest water absorption capacity,reached 14.56 g/g.When starch is aged,the swelled degree of chestnut starch decreases.The crystallinity of the aged starch is lower than that of the original starch.The longer the aged time,the greater the retrogradated enthalpy of the starch,indicated that the aged degree is also increased.Research on starch digestibility found that the greater the aged degree,the smaller the starch hydrolysis rate,the lower the RDS content,from 39.42%to 29.85%,and the higher the resistant starch content.The analysis of starch molecular mobility shows that the aged of starch will increase the bound water T₂₁1 in starch and decrease the free water T₂₃.2.Compared with the original starch,the swelled degree of chestnut starch added xanthan gum and guar gum increased to different degrees.The larger the amount of colloid added,the greater the swelled degree of starch,which can reach25.83 g/g.At the initial stage of starch aged,the light transmittance of the mixed system decreased rapidly,and decreased gradually after 7 days.Under the same standed time,the supernatant of the mixed system was significantly reduced,slowed down the coagulation and sedimentation rate of starch.Starch added xanthan gum was more stable than guar bean.After the addition of hydrophilic colloid,the enthalpy of regeneration of the compound system decreases,and decreases with the increase of colloid concentration.The addition of xanthan gum to chestnut starch significantly reduced the disintegration value and the final viscosity significantly increased.However,the peak viscosity did not change regularly with the increase of xanthan gum.High concentration of xanthan gum increased the peak viscosity of chestnut starch,while low concentration of xanthan gum decreased the peak viscosity.After guar gum was added,the gelatinization temperature,peak viscosity,disintegration value,retrogradation value and final viscosity of chestnut starch increased significantly,and increased with the increase of added concentration.In general,xanthan gum and guar gum can change many physical and chemical properties of chestnut starch during gelation and retrogradation,and have good inhibitory effect on retrogradation.3.According to response surface analysis,the optimal conditions for prepared resistant starch by autoclave method are as follows:starch milk concentration 21%,autoclave at 119?for 30min.Under these conditions,the content of resistant starch was?43.43±0.5?%.4.Through orthogonal test,the best formula of chestnut resistant starch slices is as follows:28%resistant starch,150s treatment time,20%white sugar and 1%edible salt.