Effect of heat-moisture treatment on physicochemical properties and digestive characteristics of sweet potato flour

In the present study, the effects of heat-moisture treatment (HMT) on the structural properties, physicochemical properties and in vitro digestibility of sweet potato flour were investigated. Moisture mass fractions of samples were set as 20%, 25%, 30% or 35%, and treated at 110 degrees C for 4 h. Gelatinization characteristics, short-range order, double helix structure, crystallinity and digestive characteristics were studied by test of pasting and thermal, analysis of X-ray diffraction spectra, infrared spectra and in vitro digestion test. The results showed that the structural characteristics of the sweet potato flour with different moisture concentrations were quite different. The viscosity, breakdown value and setback value of HMT-sweet potato flour were all lower than those of the original flour. The content of rapidly digestible starch (RDS) decreased, while the contents of slowly digestible starch (SDS) and resistant starch (RS) increased after HMT. The results showed that HMT-25 had good cold and heat stability, low pasting viscosity and high contents of SDS and RS.