Oxidative stability and in vitro digestion of menhaden oil emulsions with whey protein: Effects of EGCG conjugation and interfacial cross-linking

Abstract

The goal of this study was to improve the chemical stability of menhaden oil and control the lipolysis in emulsions with whey protein during in vitro digestion through EGCG conjugation and genipin-mediated interfacial cross-linking (CL). WPI-EGCG conjugate was successfully synthesized, confirmed by SDS-PAGE, ESI-MS, and phenolic group quantifications (125.3 mg/g), and characterized with far UV CD and ATR-FTIR. Emulsion particle diameter with WPI-EGCG is lower than with WPI. Compared to the native emulsion, WPI CL increased particle diameter and physical stability. Higher oxidative stability was observed for emulsions stabilized with WPI-EGCG conjugate than that with interfacial cross-linking due to the great antioxidant activity. Whereas, WPI CL is more effective than WPI-EGCG conjugate in hindering the rate and extent of lipolysis. The combination of EGCG conjugation and interfacial CL showed both the highest protection of menhaden oil against degradation and highest inhibition on the rate and extent of lipolysis of menhaden oil.

Keywords: Cross-linking; DPPH (PubChem CID: 2735032); Digestion; EGCG; EGCG (PubChem CID: 65064); Emulsion; Gallic acid (PubChem CID: 370); Genipin (PubChem CID: 442424); Menhaden oil; Whey protein; l-ascorbic acid (PubChem CID: 54670067).