Effect of dual modification by annealing and ultrahigh pressure on properties of starches with different polymorphs

The effects of dual modification by annealing (ANN) and ultrahigh pressure (UHP) on properties of wheat, yam, and potato starches were investigated. Compared with the single UHP treatment (400MPa), ANN-UHP (400MPa) treatment did not alter significantly the ordered structures of wheat starch, indicating that ANN treatment enhanced the stability and resistance of starch granules to the subsequent UHP treatment. In contrast, UHP (400MPa)-ANN treatment resulted in more severe disruption of ordered structures of wheat starch than did the single UHP treatment, showing that UHP-treated starch was more vulnerable to the subsequent ANN treatment. The dual modifications had little effect on granular structures of yam and potato starches. ANN-UHP (300 and 400MPa) and UHP (300MPa)-ANN treatments enhanced greatly the pasting viscosities of UHP-modified starches. Dual modifications altered greatly the pasting properties of yam and potato starches, as observed for the single ANN treatment. From this study, we proposed that ANN treatment enhanced stability of wheat starch by increasing interaction of starch chains in amorphous regions.