Complexation and conjugation between phenolic compounds and proteins: mechanisms, characterisation and applications as novel encapsulants

Food phenolic compounds (PCs) and proteins interact and react via non-covalent and covalent routes to form phenolic compound–protein (PCP) complexes and conjugates. In the last decade, increasing research has focused on protein modification based on these interactions in various food systems. This review provides the mechanism of PCP complexation and conjugation and relevant analytical techniques for detection and quantification purposes. Moreover, key functional properties of PCP complexes and conjugates, including solubility, emulsifying property, antioxidant activity, thermal stability, anti-microbial activity and digestibility, are discussed. The applications of the complexes and conjugates as novel encapsulants to stabilise bioactive but sensitive as novel food ingredients are also overviewed. It is worth noting that the correlation between PCP complexation and conjugation and these functional properties are not fully understood. There is still research paucity exploring the applications of PCP complexes and conjugates as promising encapsulants. Future research is required to advance the science in this area and facilitate application.