Effect of wheat grain germination time on physicochemical and texture properties, starch digestion, and protein hydrolysis rate in bread making

Abstract

Currently, consumers exhibit heightened interest in the nutritional quality of baked foods. The germination process of wheat affects the chemical composition of flours, the morphological characteristics of starches, and the digestibility properties of proteins and starches. Wheat grains were germinated (GG) for periods of 12 and 48 h. Mixtures were prepared using the germinated flour with different proportion of ungerminated (UG)flour for bread production. The germination time of the wheat grains resulted in alterations in lipid, protein, and carbohydrate content of the flours. Germination of wheat for 12-h (GG-12 h) caused a reduction in the values of maximum extension resistance (0.28 N–0.11 N) and maximum extensibility (10.19 mm–4.15 mm) in the dough, when compared to the UG wheat dough. Breads made with germinated flours exhibited a higher specific volume and a lower hardness compared to breads made with ungerminated flour. This is attributed to the enhanced gas retention capacity during fermentation and the interaction of gluten proteins modified by germination. Rapid digestibility of starch (RDS) value in the GG-48 h bread, was lower, 38.18%, compared to UG bread, 44.51%. Conversely, the slow digestibility of starch (SDS) value in the GG-48 h bread was higher, 13.15%, compared to UG bread, 3.32%. Also, the in vitro protein digestibility value in the GG-48 h was higher, 80.32% compared to UG bread, 76.61%, which indicated that the germination process favors the quality of the bread.