Physical and structural properties of peanut protein isolate-gum Arabic films prepared by various glycation time

Peanut protein isolate (PPI) was glycated with gum Arabic for 3, 6 and 9 days respectively to study the effect of different degree of graft on the physical and structural properties of glycated films. As the glycation continued, the degree of graft of PPI-gum Arabic conjugates increased gradually, the degree of crosslinking between PPI and gum Arabic in films also increased. Compared to PPI films, glycated films had increased tensile strength, decreased water vapor permeability (WVP), but decreased elongation. As the glycation proceeded from 3 to 9 days, the tensile strength of glycated films decreased, the WVP and the elongation increased gradually. This phenomenon may be caused by the decreased crystalline and increased amorphous structure of glycated films with the glycation time, which was confirmed by X-ray diffractometry and scanning electron microscopy. Disulfide bonds were the predominant interactive forces involved in all film networks. The result suggested that as the glycation continued, the level of disulfide bonds in PPI-gum Arabic films reached equilibrium after 6 days glycation.