Effect of heat-moisture treatment on the functional and rheological characteristics of cassava (Manihot esculenta) starch

The major drawback of most starchy food is its inability to withstand high-temperature conditions, shearing force and acidity, which limits its usage in the food industry. This study investigates the effect of heat-moisture treatment (HMT) at varying moisture content (10–30% wet basis), drying temperature (80–100 °C) and time (2–8 h) on the functional and rheological properties of cassava starch using response surface methodology (RSM) by adopting a Box–Behnken design method. Cassava roots were processed into modified starch under various processing conditions. Results showed an increase in the water absorption index, solubility and swelling power while there was a slight reduction in the loose bulk density and tapped bulk density. The starch viscosity ranged between 4182 and 4268 Cps. Consistency ranged between 2.51 and 2.56 g/mL and the flow behaviour index ranged between 2.70 and 2.82. Optimal processing conditions for cassava starch were achieved with a moisture content of 30%, drying temperature of 90 °C and time of 2 h. These variables are important to consider for processing of cassava starch with improved consumer acceptability and potential large-scale production of baked foods, gel formation and custard production.