Understanding the structural, pasting and digestion properties of starch isolated from frozen wheat dough

The multi-scale structure and physicochemical properties (e.g., pasting and digestion features) of starch isolated from native and frozen dough (storage at −18 °C for 10, 20 and 30 days, respectively) were investigated with combined analytical methods. Differential scanning calorimetry revealed increased freezable water contents as the extension of frozen storage time. Results showed that frozen storage treatment disrupted the granular structure but increased the particle size and ordered degree of semi-crystalline lamellae system involving lamellar structure, crystalline structure, short-rang ordered molecular structure and helical structures. And these multi-scale structural alterations were more obvious with the storage time increasing. As for gelatinization and pasting properties of frozen starches, it reflected an improved thermal-stability (e.g., increased Tc and pasting temperature) and decreased viscosity parameters such as peak and final viscosity, which may be due to the rearrangement and ordered packing of starch molecular chains during frozen storage. However, the frozen storage treatment caused increased digestibility of wheat starch by promoting the access and binding of enzymes to starch. Therefore, these results extended the knowledge of starch microstructures and technological properties during frozen storage, which may be beneficial to promote better preservation of frozen foods.