Effect of transglutaminase on the structure, properties and oil absorption of wheat flour.

The structure, properties, as well as the oil absorption characteristics of wheat flour (WF) treated with varying concentrations of transglutaminase (TG) (0 U/g ∼ 50 U/g) were characterized. The content of free amino groups in WF modified by TG (TG-WF) decreased and protein aggregated. The isopeptide bonds and disulfide bonds played important roles in protein crosslinking. The thermal stability, the peak viscosity after gelatinization and protein secondary structure stability of TG-WF were improved. In addition, the oil absorption and surface oil content of TG-WF after frying were reduced. TG enhanced the protein-protein interactions in WF, so that protein played barrier roles in the process of high-temperature frying, protecting the starch particles covered by them from the infiltration of oil, thus reducing the oil absorption of TG-WF during frying. Among them, the oil content of TG-WF-30 U/g after frying was the lowest, which decreased by 10.73 % compared with the control group. [Display omitted] • TG can catalyze protein cross-linking to form network structure. • TG changed the content of inter-molecular forces and secondary structures of protein. • The modification of WF by TG occurred in non-gelatinizing and non-dough system. • The thermal stability and peak viscosity of TG-WF were improved. • The oil content of WF modified by TG were decreased after frying. [ABSTRACT FROM AUTHOR]