Recent advances in nutraceutical delivery systems constructed by protein–polysaccharide complexes: A systematic review

Most nutraceuticals have low stability and solubility, making it difficult to achieve ideal bioavailability by directly incorporating into food. Therefore, constructing delivery systems to protect nutraceuticals is an essential strategy. Proteins and polysaccharides have become ideal materials for encapsulating nutraceuticals due to their superior nutritional value, edible safety, and physicochemical properties. This review first introduces the binding methods of protein-polysaccharide complexes and analyzes their respective merits, defects, and applications. Then, various protein-polysaccharide complex-based nutraceutical delivery systems are systematically summarized, including emulsions, gels, nanoparticles, microcapsules, complexes, and films, which can improve the stability, encapsulation efficiency, and bioaccessibility of nutraceuticals. In addition to traditional globular proteins mentioned in previous reviews, this review also introduces the advantages of another morphology of proteins (protein fibrils with linear structure) in the formation of protein-polysaccharide complexes and the construction of nutraceutical delivery systems. Next, the affecting factors are analyzed to achieve the precise control of protein-polysaccharide complex-based nutraceutical delivery systems. To improve public acceptability of protein-polysaccharide complex-based nutraceutical delivery systems, the safety and regulatory aspects are also discussed in detail. Moreover, the applications of such delivery systems are presented, including dietary supplements, food ingredients, food packaging, and food detection. Finally, several promising research directions that had not been provided before are innovatively proposed, including cell-cultured meat scaffolds, plant-based meat analogs, three-dimensional printing inks, and "three reductions" foods. Overall, this review provides guidance for designing protein-polysaccharide complex-based nutraceutical delivery systems with customized nutrition and superior bioavailability.