Insights into the multiscale structure and pasting properties of ball-milled waxy maize and waxy rice starches.

The effects of ball-milling on the pasting properties of waxy maize starch (WMS) and waxy rice starch (WRS) were investigated from a multiscale structural view. The results confirmed that ball-milling significantly destroyed the structures of the two waxy starches (especially WMS). Specifically, ball-milling led to obvious grooves on the surface of starch granules, a decrease in crystallinity and the degree of short-range order, and a reduction in double-helix components. Meanwhile, small-angle X-ray scattering results indicated that the semicrystalline lamellae of starch were disrupted after ball-milling. Ball-milling decreased the pasting temperatures. Furthermore, ball-milled starches exhibited lower peak and breakdown viscosity and weakened tendency to retrogradation. These results implied that ball-milling induced structural changes in starch that significantly affected its pasting properties. Hence, ball-milled starch may serve as food ingredients with low pasting temperature and paste viscosity as well as high paste stability under heating/cooling and shearing.