Chitin oligosaccharides for the food industry: production and applications

Chitin oligosaccharides (CHOS), high-value-added oligomers linked by N-acetyl-d-glucosamine (GlcNAc, NAG), and a small amount of d-glucosamine (GlcN, GA), have aroused increasing interest due to their excellent biological properties, including antibacterial, anti-inflammatory, and immunoprotective activities, and intestinal regulation. The efficient production and utilization of CHOS with high performance can solve problems from chitin as biowaste. However, the large-scale production of well-defined CHOS has not been fully accomplished due to the limited biotechnology and separation methods, thus impeding the research on their biological functions as well as their accurate applications. In this review, we comprehensively summarize the current preparation methods of CHOS, including the chemical, physical, enzymatic and biosynthetic methods. The advantages and disadvantages of the methods are discussed in terms of efficiency, economy, and environmental effects. Furthermore, the applications of CHOS in the food industry and their contributions to human health based on their excellent bioactivities are expounded. It is hoped that this review will help in providing new insights into the production of CHOS with high precision, and support the application of CHOS in serving the food industry as nutritional supplements or foods for special medical purposes.