Abstract

Red sorghum starch was physically modified by annealing and heat moisture treatment. The swelling power and solubility increased with increasing temperature range (60-90°), while annealing and heat-moisture treatment decreased swelling power and solubility of starch. Solubility and swelling were pH dependent with higher values obtained at pH 12 in both native and modified starches. Water absorption capacities of both annealed and heat-moisture treated starches increased with increasing levels of moisture treatment while highest value was observed in annealed starch. Oil absorption capacity of annealed starch was increased which was contrast to heat-moisture treated starches which decreased from 160 glg in native starch to 140 glg in HMR₁₈ and HMR₂₇. Pasting analysis in the Rapid Visco Analyser (RVA) revealed that both annealing and heat-moisture treatment increased pasting temperature, while alkaline water retention improved after physical modification.

Key words: Red sorghum starch, heat moisture treatments, annealing, functional properties.