Multiscale structural changes and retrogradation effects of addition of sodium alginate to fermented and native wheat starch.

This work investigated the changes in multi-scale structure and retrogradation properties of native wheat starches (NS) modified by sodium alginate (AG) with and without fermentation. AG adhered on the surface of NS granules and fermentation promoted the adhesions. Compared with the addition of AG alone, dual modification by fermentation and AG together showed a greater effect to increase the weight-average molecular weight and reduce the relative crystallinity and double helix degree of NS. Small angle X-ray diffraction results showed a significant increase in amorphous region with dual modification compared with AG alone. Additionally, dual modification greatly slowed the increase of relative crystallinity and the enthalpy (ΔH) of NS paste during storage. The results of this study suggest that dual modification is a more effective approach to modify structures and properties of wheat starch than single AG treatment, and suggest its potential industrial application in starch-based foods.