Effects of Oxidation on Water Distribution and Physicochemical Properties of Porcine Myofibrillar Protein Gel

Abstract

The effects of hydroxyl radicals induced oxidation on water distribution of porcine myofibrillar protein (MP) gels were investigated using nuclear magnetic resonance (NMR) and magnetic resonance imaging (MRI), and relationship between MP gel properties and water distribution was analyzed with Pearson’s correlation. Results of NMR spin-spin relaxation time (T2) and MRI suggested that, comparing with unoxidized MP gel, the population of immobile water of gel (P22) decreased by 18.81 %, while that of free water (P23) increased by 85.56 %, and grey scale value decreased by 18.52 %, after being oxidized with 20 mM H2O2, respectively. Images of scanning electron microscope (SEM) showed the highest degree of oxidation led to the most coarse and porous gel-network. Gel properties including WHC, whiteness and strength of MP gels decreased by 14.65 %, 2.83 % and 52.74 % after being oxidized with 20 mM H2O2 (p < 0.05), respectively. Pearson’s correlation analysis showed oxidation, gel-properties and NMR results were highly correlated (p < 0.05). Therefore, we hypothesized that hydroxyl radicals induced oxidation resulted in immobile water shifting to free water partly, thus reduced the abundance of water and gel properties of gels.