Physicochemical and functional properties of heat-moisture treated purple sweet potato (ipomoea batatas) and yam (dioscoreacea alata) starches +CD

Abstract

Heat-moisture treatment is considered as a hydrothermal treatment that improves resistant starch (RS) content of starch which has potential application in production of the starch-based food with high-health benefit effects. In this study, the starches extracted from purple sweet potato (Ipomoea batatas) and yam (Dioscorea alata) were hydrothermally modified by heat moisture treatment (HMT) to improve RS contents of these starches. The starches were adjusted to 30% moisture content by adding of 0.2M acetic, citric, lactic acid and then were heated at 100 C for 8 hours. o After treatment, the impact on yields of RS, physicochemical and functional properties were investigated. The RS contents of treated starches significantly increased in comparison with native starch, in which yam treated starches had higher RS level than treated purple sweet potato starches. When heated in temperature ranged of 40-90 C, swelling power and solubility of native and heat- 0 moisture-treated starches increased with increasing temperature. X-ray pattern shows that native purple sweet potato and yam had A-type and B-type, respectively. These crystalline structures did not change after HMT with addition of 0.2M acetic, lactic or citric acid. The findings provide that functionality of purple sweet potato and yam starch can be altered to suit with particular industrial need. Key words: purple sweet potato starch, yam starch, resistant starch, functional properties, physicochemical properties, heat moisture treatment, organic acids.