Study on the preparation and physicochemical characteristics of taro starch acetate

Taro starch was esterify with acetate,using acetic anhydride as the reagent. The influences of reaction temperature,p H,the amount of acetic anhydride and reaction time on the acetyl content of the product were studied and the preparation conditions were optimized.SEM and XRD were applied to determine the properties of taro starch acetate,and comparitions were made with taro starch.Reaction temperature,p H,and reaction time had the most significant effect on the acetyl content( p < 0.01),the amount of acetic anhydride( 0.16 ~ 0.37 m L) had significant effect on the acetyl content( p < 0.05),and the amount of acetic anhydride( 0.37 ~ 0.51 m L) had no significant effect on the acetyl content( p > 0.05).In an orthogonal experiment,the optimum technological conditions were determined: reaction temperature 25℃,p H8.0,the amount of acetic anhydride 10% and reaction time 2h.Under the condition,the acetyl content of the resulting product was 3.56%. Physical and chemical properties test showed that the transparency increased by 41.28%,the solubility increased by 12.36% and the expansion increased by 2.94%. XRD spectra indicated that the diffraction diagram of taro starch was concordant with taro starch,and type crystal starch was formed A type. SEM showed taro starch granules were intact,no cracks,the surface was smooth,the morphology of polyhedral,there were many small particles around large granular starch.Taro starch acetate granules were alike with taro starch but porous.