Enhancement of soy protein functionality by conjugation or complexation with polysaccharides or polyphenols: A review

Soy proteins have good nutritional quality and exhibit a range of useful functional attributes, making them a viable option for replacing animal proteins in the development of more sustainable and eco-friendly plant-based food products. Nevertheless, soy proteins are prone to denaturation and/or aggregation under conditions they encounter in some food and beverage products (including certain pH, ionic, and thermal conditions), which adversely impact their functional performance. This problem can often be overcome by covalently (conjugation) or noncovalently (complexation) linking the soy proteins to polysaccharides or polyphenols, thereby expanding their application scope. Compared to soy proteins alone, these conjugates or complexes exhibit enhanced technofunctional performance, including improved solubility, emulsification, foaming, gelling, antimicrobial properties, and antioxidant capacities. Conjugates are typically more stable than complexes, which may be an advantage for some food applications. However, complexes do not require additional regulatory approval, which makes them more suitable for most food applications. This review aims to comprehensively examine the enhancement of soy protein functionality through conjugation or complexation with polysaccharides or polyphenols. The research focuses on how these modifications enhance solubility, emulsification potential, foaming, gelling, and antioxidant properties, reduce the allergenicity of soy proteins, and enable their potential applications in plant-based food development, 3D food printing, fat substitutes, functional food carriers, and hypoallergenic foods.