Effects of glutenin in wheat gluten on retrogradation of wheat starch

Abstract

Retrogradation is the process of starch recrystallization, and it profoundly affects the quality, acceptability and shelf-life of starch-containing foods. The influence of glutelin on the wheat starch retrogradation was studied in this paper. Glutenin was isolated from wheat flour, and its effect on retrogradation of wheat starch, amylose and amylopectin was investigated with UV–Vis (starch-iodine), IR and 13C NMR. The results showed that glutenin probably interacted with amylose during gelation and retrogradation of starch. The results of IR showed that the addition of glutenin to wheat starch reduced the number of hydrogen bonds formed between amyloses during retrogradation. The 13C NMR results suggested that tyrosine (Tyr) of glutenin might combine with amylose at the first carbon atom when they were mixed homogeneously and such combination was strengthened during retrogradation. Glutenin and amylose formed double helix with each other completely and hindered amylose–amylose short-term retrogradation of wheat starch, and glutenin would no longer inhibit the retrogradation of starch when all of the Tyr formed hydrogen bond with amylose. These results suggest that glutenin could play a powerful role in retarding the retrogradation of amylose, which is very important for the food industry.