Modification Of Whey Protein By Transglutaminase In The Presence Of Oligochitosan

The paper modified the whey protein synergy with oligochitosan by using of the advantage of abundant free amino of oligochitosan and the function of the TGase, and discussing preliminarily the reaction conditions. Studying the modified whey protein functional characteristics, which the aim is to provide reference of research and development of functional food material and additive.To investigate the occurrence of modification. Confirming qualitative by utilizing SDS-PAGE, FT-IR, and HPLC quantitative analysis of protein modification of oligosaccharide, and their relative contents were determined, in order to further prove the occurrence of modification.The modification conditions of whey protein-oligochitosan modified protein were optimized, and the effects of reaction time, the concentration of whey protein, the pH and the ratio of substrate to four factors on the modification were studied. The optimum conditions were determined by single factor experiment, the optimum conditions were as follows: the reaction time was 2 h, the concentration of whey protein was 3%, the reaction pH 6.0, whey protein and the quality of chitosan oligosaccharide=3:1. The glycosylation degree of the modified protein was 371.86 mg/g under the optimum conditions.The solubility, emulsifying ability, thermal stability, fluorescence property, rheological property and rheological property of whey protein were improved after the modification of the enzymatic action. Which dissolved in partial acidic conditions was better, and in the partial alkaline conditions had lower solubility; and the emulsifying activity was decreased with the increase of substrate concentration, emulsion stability in protein concentration for 0.8% is the highest; the thermal stability of the modified proteins with small amplitude enhancement and fluorescence intensity is increased slightly, and the surface viscosity increases with the increase of the concentration of substrate.The films of whey protein after modification, its tensile strength and elongation at break and the thermal stability were significantly increased, and the water-soluble of films have marked lower compared to pure whey protein membrane, which has a certain superiority forthe practical application of membrane. But the water vapor transmittance and the light transmittance of modified protein membrane were slightly higher than that of protein membrane, which may be limit its application in the field of production.