Enhanced stability and antioxidant activity of pickering emulsions stabilized by chayote tuber starch-tea polyphenol composites

Starch has emerged as a promising Pickering emulsion stabilizer due to its low cost, renewability, and biocompatibility; however, its poor interfacial activity and lack of functional properties have limited its broader applications. In the present work, composites of chayote tuber starch (CTS) and tea polyphenols (TP) were prepared via a co-gelatinization method. The effects of varying TP concentrations (0–20 %) on the physicochemical, structural, and emulsifying properties of the CTS/TP composites as Pickering emulsion stabilizers were systematically investigated. FT-IR and XRD analyses revealed that hydrogen-bonding interactions between TP and CTS disrupted both short-range and long-range molecular order, resulting in a looser and more porous structure. The addition of TP increased particle size while decreasing the ζ-potential, gelatinization enthalpy, and viscosity of the composites. CTS/TP10 composites exhibited optimal interfacial properties, as the interfacial tension decreased from 64.48 to 33.53 mN/m and the contact angle increased from 60.27° to 93.55°. Compared with emulsions stabilized by pure CTS particles, emulsions stabilized by CTS/TP10 composites exhibited significantly superior physical stability. Moreover, TP, as a potent antioxidant, inhibited free radical-induced damage, thereby suppressing lipid oxidation within the emulsion system. Specifically, when the TP concentration in the CTS/TP composites was 10 %, the peroxide value (POV) and thiobarbituric acid reactive substances (TBARS) decreased by 29.95 % and 84.94 %, respectively, after 15 days of accelerated oxidation testing. In conclusion, CTS/TP composites exhibited excellent interfacial properties and antioxidant activity, highlighting their potential as multifunctional emulsifiers capable of inhibiting oil oxidation.