Stability and lipid oxidation of oil-in-water emulsion stabilized by Maillard conjugates of soybean phosphatidylethanolamine with different polysaccharides

Lipid oxidation and instability in oil-in-water (O/W) emulsion are the main challenges in emulsion-based foods. Polysaccharide-induced Maillard conjugation of soybean phosphatidylethanolamine (SP) holds great potential in improving physicochemical stability of emulsions. This work applied tamarind gum, pectin, inulin and maltodextrin to conjugate with SP to obtain the four Maillard conjugates (MCs), and investigated their difference in interface and anti-oxidant abilities in emulsions. Results showed that lower polymerization degree of polysaccharide moieties (tamarind gum＞pectin＞maltodextrin＞inulin) caused higher glycation degree in MC: inulin-SP-MC＞maltodextrin-SP-MC＞pectin-SP-MC ≈ tamarind gum-SP-MC, which corresponded their color changes. Compared with unconjugated mixtures, interface activity and anti-oxidant abilities of MCs were strengthened. Among the four MCs, tamarind gum-SP-MC (7.77 mN/m) and pectin-SP-MC (8.42 mN/m) could decrease interfacial tension more largely. It was due to the faster interface saturation benefited from broader steric network of tamarind gum and pectin moieties, and stable interfacial absorption facilitated by improved zeta potential and lipophilicity. Pectin-SP-MC also exhibited the highest anti-oxidant ability (DPPH scavenging ability of 97.81% and ferric-reducing antioxidant power of 2.742 A). It was attributed to the combined effects of grafting degree, interface activity and chain length of pectin moiety. As a result, emulsions stabilized by pectin-SP-MC had less water loss, smaller droplet sizes, and lower contents of oxidation products. Maillard reaction between SP and pectin was favorable to produce MCs with higher potential for the improvements of physical and oxidative stability of O/W emulsions. © 2024