Structural, thermal and rheological properties of starches isolated from Indian quinoa varieties.

In this study starches isolated from Indian quinoa varieties were examined for physicochemical, morphological, thermal and rheological properties. Among isolated starches V showed higher starch yield and lower purity (48.45% and 98.32%) than V (41.28 and 98.53%). The amylose content was higher for V (12.10%) than V (9.46%). Swelling powers and solubility of the starches increased with increasing temperature. Peak viscosity (386.4 RVU) was higher for V. In contrast V showed higher pasting temperature (72.85°C). Low setback viscosity of the starches suggests that they can be profitably used in frozen and refrigerated foods. Starch granules from both varieties were irregular, angular and polygonal in shape. The starch granule size obtained by SEM was 1.23μm for V and 1.19μm for V. Both starches showed a typical A-type diffractrometric pattern with varying crystallinity. Further V showed lower transition temperatures (To, Tp and Tc) than V. FTIR spectroscopy showed higher intensity and broader shape of V at OH stretch which can be due to its higher crystallinity. Increased interest is shown in quinoa starch because of its unique microcrystalline granules. Higher yield and purity values suggest that both varieties can be exploited for commercial starch utilization.