Abstract
•BET and SEM were used to observe the changes in the microstructure of MP gel.•Excessive oxidation will lead to the increase of pore diameter of MP gel.•Excessive oxidation can cause changes in the water state in the MP gel.•Moderate oxidation can increase the strength and WHC of MP gel.
The aim of this study was to investigate the effects of oxidation on the structure of pork myofibrillar proteins (MPs) and the water retention mechanism of MPs gel. In a Fenton reaction system, protein oxidation increases (P < 0.05) with hydrogen peroxide (H2O2) concentration (0, 0.5, 1, 3, 5, 10, and 20 mmol/L). The Brunauer–Emmett–Teller surface area of the proteins gel gradually increased (P < 0.05) from 6.17 m2/g to 14.73 m2/g. Low field nuclear magnetic resonance results showed that immobilized water in the gel gradually decreased but free water content gradually increased (P < 0.05). Gel strength and water holding capacity (WHC) increased and then decreased. The results reveal that moderate oxidation contributes to the compact and uniform pore structure, higher WHC of proteins gel as well. However, excessive oxidation leads to increase pores and changes in water states of gel, leading to lower WHC.