Biotinylated caffeic acid covalent binding with myofibrillar proteins in alkaline conditions: Identification of protein-phenol adducts and alterations in protein properties.

Abstract

In this study, the effects of covalent interactions between myofibrillar proteins (MP) and caffeic acid (CA) were investigated. Protein-phenol adducts were identified by biotinylated caffeic acid (BioC) used as a substitution of CA. The total sulfhydryls and free amines content were decreased (p<0.05). The α-helix structure of MP increased (p<0.05) and MP gel properties enhanced slightly at low dosages of CA (10 and 50μM), and both were impaired significantly (p<0.05) at high dosages of CA (250 and 1250μM). Two prominent adducts of myosin heavy chain (MHC)-BioC and Actin-BioC were identified by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE), which gradually increased at low concentrations of BioC (10 and 50μM), and raised significantly at the concentration of 1250μM. According to the correlation analysis, MHC-BioC and Actin-BioC adducts showed a significant negative correlation with gel properties, such as G', hardness, and water holding capacity (WHC) (p<0.01), which indicated that the covalent interactions between MP and CA significantly affected the quality of meat products.