Abstract: Bioactive substances from foods are of great interest to researchers because of their excellent efficacy in health regulation and disease prevention. However, they are easily damaged by environmental conditions and extreme pH in the gastrointestinal tract and thus exhibits extremely low bioavailability in vivo, limiting their applications. Numerous studies have shown that casein modified with polysaccharides by the Maillard reaction has good functional properties and environmental stability and can be used as a delivery system for bioactive substances to improve their stability in the gastric environment and for their targeted release in the small intestine. This paper reviews the structure and properties of casein, the preparation methods for casein modified by the Maillard reaction, the types of casein modified by the Maillard reaction as a delivery vehicle for bioactive substances and its application in delivery systems for bioactive substances, and discusses the release characteristics of bioactive substances in simulated gastrointestinal digestion system. Besides, this article describes future prospects for the application of casein modified by the Maillard reaction in the preparation of delivery systems and discusses the problems to be solved in this field. Hopefully, this review will be helpful to enhance the bioavailability and utilization of food-derived bioactive substances.

Key words: casein; Maillard reaction; preparation method; delivery system; bioavailability