Alginate properties and applications

Alginates are linear biopolymers of 1,4-linked β-D-mannuronic acid (M) and 1,4 α-L-guluronic acid (G) residues, which are arranged in homogenous (poly-G, poly-M) or heterogenous (MG) block-like patterns. The physiological and chemical characteristics of alginates depend on this arrangement of residues. Alginates are very abundant in nature. In brown algae, they are produced as the skeletal component of their cell walls, comprising up to 40% of dry weight. Some bacteria can also synthesize alginates. Alginates have excellent biocompatibility, biodegradation, stable structure, and nontoxicity. Accordingly, they are widely used in biomedicine (such as shaped tablets, dentistry, and wound dressing), food industry (such as ice cream, jelly, lactic beverage, dressing, instant noodle, and beer), animal feed, textile printing industry, papermaking, cosmetic industry, sewage treatment, and daily chemicals. As attractive compounds, alginates have attracted increasing attention in the research world. This chapter summarizes their structures, properties, the modification of alginates, various characterization techniques, processing methods, and dynamic properties. The wide applications of alginates in biomedicine, food, industrial and environmental sciences are reviewed. The future development targets in various fields are prospected.