Exploration of Natural Protein–Polysaccharide–Polyphenol Ternary Complexes from Grape Pomace for Clean-Label Pickering Emulsions Through pH Adjustment

Grape pomace represents a major organic solid waste generated by the wine industry, but its application has been largely unexplored. On the other hand, so far, stable and sustainable raw materials for producing stable, edible Pickering emulsifiers suitable for the food industry have been lacking. To solve these problems, this study established a mild but effective co-extraction method to obtain protein-polysaccharide-polyphenol ternary complexes (GPTCs) from grape pomace. Subsequently, these complexes were directly developed into an edible Pickering emulsifier by a pH-controlled method. Results showed that a series of properties related to the Pickering emulsifier, such as particle size, surface charge, wettability, and interfacial adsorption behavior, could be easily controlled by adjusting the solution's pH. Consequently, the GPTC prepared at pH 7.0 exhibited optimal emulsifying performance. The resulting particles had an average particle size of approximately 111 nm, and stabilized Pickering emulsions with a volume-weighted mean oil droplet diameter (D [4,3]) of 9.49 μm, indicating high emulsion stability. Collectively, this study provided an actionable approach for the green, high-value utilization of wine byproducts by establishing a pH-responsive design framework for edible Pickering emulsifiers.