Myofibrillar Protein Cross-Linking and Gelling Behavior Modified by Structurally Relevant Phenolic Compounds

Protein gelation is an important phenomenon in processed meats. The present study investigated the structure-activity relationship of six phenolic compounds, that is, gallic acid (GA), chlorogenic acid (CA), propyl gallate (PG), quercetin (QT), catechin (CC), and (-)-epigallocatechin-3-gallate (EGCG) in a myofibrillar protein (MP) gelling system under controlled oxidative conditions. All phenolics induced unfolding and promoted cross-linking of MP via sulfhydryl or amine groups. At an equal molar concentration, EGCG boosted the elastic MP gel network more than other phenolics except PG. However, all three monophenols (GA, CA, and PG) and the diphenol QT increased the MP gel strength more than CC (diphenol) and EGCG (triphenol). The flavanol structure appeared to interfere with the protein gel structure development. All phenolics retarded lipid oxidation in MP-emulsion composite gels during refrigerated storage with the least polar phenolic compounds, PG and QT, showing the greatest efficacy.