Protein–Polysaccharide Complexes for O/W Emulsions: Structural Engineering and Their Relevance to Food Stability and Safety

Natural protein–polysaccharide complexes (PPCs) have emerged as promising next-generation emulsifiers for oil-in-water (O/W) emulsions, simultaneously meeting functionality and safety requirements in contemporary food systems. As consumer and regulatory focus intensifies on clean-label formulations, nutritional enhancement, and environmental sustainability, PPC-based emulsifiers offer a biocompatible alternative to synthetic or single-component stabilizers. These complexes improve the texture and sensory quality of emulsified foods, while also contributing to food safety by improving stability and potentially reducing the need for synthetic additives. This review comprehensively evaluates the interfacial behavior and emulsification performance of PPCs, emphasizing how the choice of source materials, molecular interactions, and structural modulation techniques influence functionality. Special attention is given to emerging technologies that facilitate the design of PPCs with targeted release, improved allergenicity profiles, and improved microbial stability, leading to safer and more resilient food matrices. Additionally, it explores opportunities to scale PPC technologies by utilizing underutilized protein/polysaccharide sources, aligning with the goals of sustainable food production. These advances position PPCs not only as multifunctional emulsifiers but also as strategic components in the development of safe, nutritious, and future-ready food products.