Promotion of fishy odor release by phenolic compounds through interactions with myofibrillar protein

Abstract

Phenolic compounds are effective means of promoting the release of fishy odor compounds, thereby significantly decreasing the fishy odor of fish products. In this study, the mechanisms underlying the promotion of fishy odor release by three phenolic compounds, rosmarinic acid (RA), carnosic acid (CA), and carnosol (CS), through interactions with the myofibrillar protein (MP) of silver carp were investigated. The addition of phenolic compounds (5, 25 and 125 μmol/g protein) was found to significantly alter the conformation of MP and decrease the fishy odor compound binding sites through the formation of phenolic compound-protein complexes. Of note, both sensory evaluation and gas chromatography analysis revealed a significant facilitation of fishy odor compound release by phenolic compounds in the presence of MP. In MP treated with 125 μmol/g protein of RA, the contents of fishy odor compounds increased from 30% to- 37%, with an increase of fishy odor score of 58%, compared to the un-treated control. Similar changes were observed when treating MP with CA or CS. These changes were likely due to the enhancement of protein-protein interactions caused by phenolic compounds and competition between fishy odor and phenolic compounds for hydrophobic binding sites in MP. The release of fishy odor compounds increased as the amount of phenolic compounds utilized increased with RA being the strongest promoter of fishy odor compounds, followed by CA and CS.

Keywords: Binding sites; Fishy odor compounds; Myofibrillar protein; Phenolic compounds; Protein structure.