Effect of heat-moisture treatment (HMT) on the physico-chemical, structural, and functional properties of Ethiopian potato starch and flour

This study evaluated the physicochemical, morphological and functional properties of starch and flour of Ethiopian potato (EP) subjected to heat-moisture treatment (HMT) at varying moisture levels (20 %, and 30 %) and a temperature of 100 °C for 6 h. The results revealed significant variations ( p ≤ 0.05) in the physicochemical properties of starch and flour samples, including colour, amylose content, and crystallinity. HMT notably affected these properties, leading to a decrease in lightness (L*) and whiteness values, particularly for HMT-treated samples, which were attributed to Maillard reactions. The amylose content increased from 23.02% in untreated starch to 23.95 % in HMTS-30, indicating that higher moisture content during HMT enhances amylose levels. X-ray diffraction analysis demonstrated the retention of B-type crystalline structure despite a reduction in overall crystallinity (1.99 % for starch and 2.62 % for flour) after HMT, attributed to disruption of the crystalline arrangement. Fourier Transform Infrared (FTIR) spectroscopy confirmed no significant shifts in characteristic absorption peaks between native and HMT-treated samples, indicating structural integrity. Pasting properties showed a significant reduction in viscosity parameters, with peak viscosity decreasing from 8346.15 mPa.s (NS) to 3950.79 mPa.s (HMTS-30) in starch. The thermal properties indicated the To, Tp, and Tc values of HMT samples, both starch and flour, were higher than those of the native EP flour and starch. This study highlights the impact of modification on the physicochemical, structural, functional characteristics of EP flour and starch, providing valuable insights for its application in food products.