Effect of H2O2 and pH on properties of myofibrillar proteins from Yak muscle during thermal gelation process

This paper examined the thermal gelation of yak myofibrillar protein (MP) incubated in a Fenton oxidation system at different pH values for 24 h. The effect of protein oxidation on the gel properties at different pH levels was explored by studying the water-holding capacity (WHC), solubility, texture, and other characteristics, while the chemical force, rheological, and microstructural variation in these conditions were analyzed. The results showed that protein oxidation negatively impacted the yak meat MP gel characteristics (p < 0.05). Increasing the H₂O₂ interval at different pH levels significantly decreased (p < 0.05) the WHC, solubility, and texture of the protein gel, the average reduction was 7.5%, 27.5%, 12.5% respectively. The H₂O₂ concentration and pH level substantially affected ionic and hydrogen bond formation (p < 0.05). Oxidation had the most obvious impact on the gel characteristics at pH 5.0. The MP gel displayed a loose, disordered microstructure with the lowest WHC, textural strength, storage modulus (G'), and intermolecular protein force. Oxidation had the least impact on the gel properties at pH 6.0. The MP gel exhibited the highest textural strength, G', and intermolecular forces, characterized by a compact, orderly microstructure with small, uniformly distributed pores. The gel displayed the best WHC after oxidation at pH 8.0.