Characterization of Amaranthus cruentus and Chenopodium quinoa Starch

Starches from amaranth (Amaranthus cruentus) and quinoa (Chenopodium quinoa) were isolated and investigated by using enzymatic assay, Rapid Visco Analysis (RVA), Differential Scanning Calorimetry (DSC), Scanning Electron Microscopy (SEM) and X-ray Diffractometry (XRD). Amylose content measured enzymatically was 7.8 and 11.2 % for amaranth and quinoa starch, respectively. Quinoa starch was much more viscous than amaranth starch and gelatinized at a lower temperature as determined with RVA. DSC demonstrated a wider gelatinization temperature range for amaranth starch (20.6°C) than for quinoa starch (11.1°C). SEM observation revealed polygonal shape of starch granules, and XRD suggested a typical Atype diffraction pattern for both the starches in question. A crystallinity of 45.5 % for amaranth and 35.4 % for quinoa starch, respectively, was also determined from the XRD collected data.