Albumins, globulins, gliadins, and glutenins were isolated from wheat flour and the effects of those proteins on retrogradation of wheat starch were investigated. The results showed that only glutenins retarded retrogradation of wheat starch and other 3 proteins promoted it. The results of IR spectra proved that no S–S linkage formed during retrogradation of wheat starch blended with wheat proteins. Combination of wheat starch and globulins or gliadins through glucosidic bonds hindered the hydrolysis of wheat starch by α-amylase. The melting peak temperatures of retrograded wheat starch attached to different proteins were 128.46, 126.14, 132.03, 121.65, and 134.84 °C for the control with no protein, albumins, glutenins, globulins, gliadins groups, respectively, and there was no second melting temperature for albumins group. Interaction of wheat proteins and starch in retrograded wheat starch greatly decreased the endothermic enthalpy (△H) of retrograded wheat starch. Retrograded wheat starch bound to gliadins might be a new kind of resistant starch based on glycosidic bond between starch and protein.
The main finding in the paper is uncovering the different effects of proteins in wheat flour on retrogradation of wheat starch. Those proteins could be used to control retrogradation of wheat starch, such as glutenins retard retrogradation of wheat starch, albumins, globulins, and gliadins promote retrogradation of wheat starch. Glycosidic bond formed between wheat starch and gliadins might greatly resist hydrolysis of wheat starch by amylase. Such retrograded wheat starch would possibly become a new kind of resistant starch.