Stabilization of anthocyanins by simultaneous encapsulation-copigmentation via protein-polysaccharide polyelectrolyte complexes

This study prepared a series of polyelectrolyte complexes (PECs) composed of heated whey protein isolate (HWPI) and different polysaccharides for simultaneous encapsulation and copigmentation of anthocyanins (ATC) and their ultimate stabilization. Four polysaccharides including chondroitin sulfate, dextran sulfate, gum arabic, and pectin were chosen due to their abilities to simultaneously complex with HWPI and copigment ATC. At pH 4.0, these PECs were formed with an average particle size of 120-360 nm, the ATC encapsulation efficiency of 62-80%, and the production yield of 47-68%, depending on the type of polysaccharides. The PECs effectively inhibited the degradation of ATC during storage and when exposed to neutral pH, ascorbic acid, and heat. Pectin had the best protection, followed by gum arabic, chondroitin sulfate, and dextran sulfate. The stabilizing effects were associated with the hydrogen bonding, hydrophobic and electrostatic interactions between HWPI and polysaccharides, conferring dense internal network and hydrophobic microenvironment in the complexes.