Abstract:In this study, the gels formed by yak muscle myofibril protein (MP) incubated for 24 h in Fenton oxidation systems at different pH values were taken as the research objects. Through examining their characteristics such as whiteness, water retention and texture, the effects of protein oxidation on the gel propertiesat different pH values were explored. The differences in chemical force, rheology and microstructure under the conditions were analyzed. The results showed that the whiteness, water-holding capacity and texture of protein gel decreased significantly with an increase of H2O2 concentration at different pH values (P＜0.05). The hydrophobic interaction force was the main force to maintain the protein gel, followed by disulfide bond, ionic bond and hydrogen bond. With the increase of H2O2 concentration, the hydrophobic interaction force and disulfide bond increase significantly, whilst the ionic bond and hydrogen bond decrease significantly (P＜0.05). When the pH value was 5.0, oxidation had the most obvious effect on the gel characteristics. MP gel had the lowest water holding capacity (77.20%), the worst texture strength (only 53.40 g), the smallest storage modulus, and the weakest intermolecular force between proteins, leading to a loose and disordered microstructure. When pH value was 6.0, oxidation had the weakest effect on gel characteristics. MP gel had the highest texture strength (61.40 g), the largest storage modulus and intermolecular force, with the microstructure being compact and orderly. This study provides a theoretical basis for the control of protein oxidation in yak meat.
