A study of some physicochemical properties of high-crystalline tapioca starch

Abstract

Tapioca starch was partially hydrolyzed in hydrochloric acid solution at room temperature for various lengths of time to obtain high-crystalline starches. RVA viscoamylograms of acid-modified starches demonstrated a very low viscosity as compared to that of native tapioca starch. The relative crystallinity of native and acid-modified tapioca starches were measured by X-ray diffraction ranging from 39.53% to 57.75%. The native and acid-modified tapioca starches were compressed into tablets using various compression forces. The % relative crystallinity of starch increased with the increase in hydrolysis time and the crushing strength of the tablet was also increased in line with the crystallinity while the amylose content decreased when the crystallinity increased. These results suggested that the erosion of amylose might cause the rearrangement of starch structure into a new more tightly packed form, which provided the higher crushing strength for the tablets.