Comparing the multi-scale structure, physicochemical properties and digestibility of wheat A- and B-starch with repeated versus continuous heat-moisture treatment

The effects of continuous heat-moisture treatment (CHM) and repeated heat-moisture treatment (RHM) on multi-scale structure, physicochemical and digestibility properties of wheat A- and B-starch were investigated and compared. Both A- and B-starch granules maintained integrity after repeated and continuous modification. Changes in starch molecules induced the diversification of crystal structure and physicochemical properties. Crystal type of CHM and RHM starches maintained the original A-type while the crystallinity decreased after treatmnt. For wheat A-starch, the RS and RDS contents of RHM starches were obviously lower than native ones while the SDS content increased. Meanwhile, the RDS and SDS contents of treated B-starch were significantly higher than native ones but the RS content was lower. At the same conditions, B-starches exhibited a lower relative crystallinity, lower viscosity parameters, lower T o , T c , T p and ΔH values than A-starches. In general, the repeated heat-moisture treated samples obtained superior characteristics than continuous treated ones, and the results of A- and B-starch varied greatly.