Abstract: Bioactive compounds have potential applications as functional ingredients in many foods and medicines. During processing, storage, and gastrointestinal digestion, bioactive substances are easily degraded, which greatly limits their applications. Therefore, researchers have expressed considerable interest in designing a food-grade delivery system. The Maillard reaction occurs naturally without the addition of chemical reagents and has been widely used to improve the functional properties of proteins. The protein-polysaccharide conjugate prepared by the Maillard reaction has high stability, and it has been widely used to deliver bioactive substances in recent years. This article reviews the effect of the Maillard reaction on the functional properties of proteins, and the applications of the protein-polysaccharide conjugate in delivery systems for bioactive substances such as emulsions, nanoparticles, nanogels, and microcapsules. Also, how the delivery systems change during digestion is discussed. Moreover, the problems to be solved and future prospects for the application of the Maillard reaction in the preparation of delivery systems are discussed.

Key words: Maillard reaction; protein-polysaccharide conjugate; bioactive compound; delivery system