STUDIES ON PHYSICAL PROPERTIES OF NATIVE, GELATINIZED AND ACETYLATED RICE STARCHES

Abstract

The physico-chemical properties of native, acetylated and gelatinized starches from commercial rice exhibited that, the gelatinized starch showed higher amylose content in comparison to acetylated one which showed no significant increasing in amylose compared with native rice starch. The swelling power in acetylated and gelatinized starches are high compared to unmodified starch. The gelatinized starch (GS) showed the highest amylase content, followed by acetylated one, which have not a significant difference in comparison to native rice starch. Its well known that, native starch have a poor solubility, however, acetylated one showed a higher solubility, and the gelatinized is the superior compared to them. The scanning electron spectroscopy did not show any significant difference between the external morphology of native and acetylated starches but in GS the starch granules size increased greatly. onset temperature (To) and peak temperature (Tp ) increased for acetylated starch, while conclusion temperature (Tc) decreased but gelatinized starche recorded a decreasing in onset temperature (To) and increasing in Tp , Tc. enthalpies of gelatinization ∆Hgel values increased for all modified starches in comparison to native starch.