Effects of Purslane Extract on the Gel Properties of Isolated Porcine Myofibrillar Proteins Under Oxidative Stress

This study investigated the effects of varying concentrations of purslane extract (PE) (0, 0.05, 0.10, 0.15, 0.20, and 0.40 mg mL −1 ) on the gelling properties of pork myofibrillar proteins (MPs) under a Fenton oxidation system, with 0.02 mg g −1 BHA as a positive control. Both BHA and PE alleviated the deterioration of gel properties induced by oxidation, as evidenced by suppressed cooking loss, improved water-holding capacity (WHC), and enhanced texture characteristics. Notably, PE at 0.20 mg mL −1 exhibited the most pronounced effects, leading to increased elasticity, cohesiveness, gumminess, and resilience, as well as maximal storage ( G ′) and loss ( G ″) modulus. LF-NMR analysis revealed that oxidation promoted the migration of water from immobilized to free states, a trend reversed by BHA and PE. The immobilized water content was significantly higher at 0.20 mg mL −1 PE than in the oxidized and BHA groups ( P  < 0.05), indicating an improved gel network. Microstructural analysis further confirmed that the addition of 0.20 mg mL −1 PE under oxidative conditions significantly improved the three-dimensional network structure of MPs gels. However, further increasing the PE concentration to 0.40 mg mL −1 deteriorated all gel properties, highlighting a concentration-dependent regulatory effect. Therefore, optimizing PE concentration is critical for practical applications. These findings provide a theoretical basis for using PE as a natural antioxidant in gel-type meat products.