Effect of heat-moisture treatment on morphological, structural and functional characteristics of ball-milled wheat starches

The effect of heat-moisture treatment (HMT) on the physicochemical properties of ball-milling (BM) modified wheat starch was investigated. The results showed that the damaged starch (DS) content and swelling power of BM modified starches decreased while their solubility increased by HMT. The gelatinization temperature of all the treated starches increased on HMT. However, the ball-milling-heat-moisture treatment (BM-HMT) starches had lower gelatinization temperature than the HMT starch without BM pretreatment. In addition, the BM-HMT starches displayed biphasic endotherms that differed from the BM starches. The crystallinity of starches milled for 0 to 1, 3, and 5 h increased by 5.50, 7.90, 3.50, and 10.30% on HMT, respectively, indicating that a certain degree of granule damage caused by BM treatment prior to HMT can enhance the mobility and realignment of resulting chains during HMT. The viscosities of the BM starches decreased on HMT, indicating enhanced shear stability and reduced retrogradation, which was similar to the effect of HMT on native starch. However, the peak, trough, and final viscosities of BM starches showed a smaller decline than that of native starch by HMT. These results demonstrate that BM-HMT can be a potential and beneficial method for wheat starch modification, providing desirable properties for food industries.