Changes in physicochemical properties and in vitro digestibility of common buckwheat starch by heat-moisture treatment and annealing

•HMT and ANN improved thermal stability of common buckwheat starch (CBS).•HMT and ANN significantly increased the amylose content in CBS.•HMT and ANN elevated slowly digested starch and resistant starch.•HMT and ANN decreased rapidly digested starch, starch hydrolysis and viscosity.•Modifications did not change the ‘A’-type crystalline pattern of CBS. Heat-moisture treatment (HMT) and annealing (ANN) were applied in the test to investigate how they can affect the physicochemical properties and in vitro digestibility of common buckwheat starch (CBS). In the practice, these two modification methods did not change typical ‘A’-type X-ray diffraction pattern of CBS. However, the gelatinization temperature, amylose content, and relative crystallinity increased and peak viscosity value and gelatinization enthalpy of CBS declined significantly. Both the solubility and swelling power, which were temperature dependent, progressively decreased along with the treatments. Remarkable increase in slowly digested starch and resistant starch level was found at the same time. Besides, the decreases of rapidly digested starch and total hydrolysis content by using HMT were greater than by using ANN. The results indicated that the ANN and HMT efficiently modified physicochemical properties and in vitro digestibility of CBS and were able to improve its thermal stability, healthy benefits and application value.