Glycation-induced structural modification of myofibrillar protein and its relation to emulsifying properties

In the present study, myofibrillar protein (MP) and dextran (DX) conjugates were prepared via glycation in a liquid solution. The effects of DX molecular weight on structural and emulsifying properties of conjugates compared with those of MP were investigated. The glycation was confirmed by evaluating modification degree of glycation (DG), electrophoresis and Fourier transform infrared spectroscopy. As DX molecular weight increased, the Ca2+-ATPase activity decreased markedly due to modification of MP, and the formation of MP-DX conjugates reduced surface hydrophobicity owing to the unfolding behaviour of MP and covalent attachment of DX. In addition, combined analysis of turbidity and reactive sulfhydryl contents indicated that MP may undergo a conformation unfolding and become looser and more flexible upon glycation. Glycation was able to increase the emulsifying activity and emulsion stability of MP, and MP-DX 70 showed the best emulsifying properties. A good correlation between reactive sulfhydryl contents and emulsifying properties was obtained, and the correlation coefficients were 0.930 for emulsifying activity and 0.961 for emulsion stability. Meanwhile, there was a negative correlation between surface hydrophobicity and emulsifying properties with correlation coefficients of −0.965 and −0.895, respectively. Overall, glycation could alter the structural characteristics and enhance the emulsifying properties of MP.