Different physicochemical, structural and digestibility characteristics of myofibrillar protein from PSE and normal pork before and after oxidation

PSE pork has a weaker texture than normal pork due to the denaturation by endogenous protease. Changes in the nutritional quality and characteristics of myofibrillar protein (MP) from PSE pork have been scarcely documented. MPs were isolated from both PSE (MPP) and normal pork (MPN) and were oxidized for 12 h at 4 °C by a hydroxyl radical generating system (10 μM FeCl3, 100 μM ascorbic acid, 0.1, 1, and 10 mM H2O2). The MPP had less aggregation and looser structure with higher surface hydrophobicity. The MPP was also less polymeric, as evidenced by intenser bands on SDS-PAGE and fewer carbonyl-NH2 interactions. The MPP particles were of smaller size, caused by the endogenous protease and oxidation, and reached the critical concentration to enhance the solubility. The altered characteristics of MPP enhanced its in vitro digestion rate and overall digestibility. In addition, the in vitro digestion rate of MPN can be enhanced if the oxidative stress is strong enough (10 mM H2O2).