Controlled Cross-Linking with Glucose Oxidase for the Enhancement of Gelling Potential of Pork Myofibrillar Protein.

Differential oxidative modifications of myofibrillar protein (MP) by hydroxyl radicals generated in an enzymatic system with glucose oxidase (GluOx) in the presence of glucose/FeSO4 versus a Fenton system (H2O2/FeSO4) were investigated. Pork MP was modified at 4 °C and pH 6.25 with hydroxyl radicals produced from 1 mg/mL glucose in the presence of 80, 160, or 320 μg/mL GluOx and 10 μM FeSO4. Total sulfhydryl content, solubility, cross-linking pattern, and gelation properties of MP were measured. H2O2 production proceeded linearly with the concentration of GluOx and increased with reaction time. GluOx- and H2O2-dose-dependent protein polymerization, evidenced by faded myosin heavy chain and actin in SDS-PAGE as well as significant decreases in sulfhydryls, coincided with protein solubility loss. Firmer and more elastic MP gels were produced by GluOx than by the Fenton system at comparable H2O2 levels due to an altered radical reaction pathway.