Influence of Cross-Linking by Microbial Transglutaminase on Physicochemical Properties of Eggshell Membrane Collagen

Abstract

Collagen from eggshell membrane (EM) was stabilized via a cross-linking procedure using microbial transglutaminase as an alternative, nontoxic cross-linking reagent for its low stability and low mechanical strength. The physicochemical features of collagen solutions (5 mg/mL), which were cross-linked by different concentrations of MTG (30, 40, 50, 60, and 70 U/g collagen), were examined. The SDS-PAGE, differential scanning calorimetry (DSC), residual amino group content, scanning electron microscopy (SEM), and viscosity of solutions were evaluated. The results revealed that applying higher concentrations of MTG in cross-linked collagen solutions leads to an increase of about 32°C–39°C in denaturation temperatures (T_d) and a 75.76% decrease in residual amino group content. The simultaneous effect of different temperatures and concentrations of MTG on viscosity illustrated an improvement of approximately 30 Pa·s in the viscosity of cross-linked collagen at 50°C. The enzymatically cross-linked porous structures displayed finer microstructure with interlinked micron-sized pores, exhibiting a 74% reduction in size compared to the uncross-linked collagen. These results suggest that combining MTG and EM as sources of collagen represents an innovative potential route for the safe cross-linking of collagen-based matrices. This innovation could have practical applications in reducing waste EM, which is a by-product of egg breaking in industrial and domestic settings, and utilize them to produce firmness and stabilize collagen.