Oligosaccharides: Structure, Function and Application

Abstract

Oligosaccharides are carbohydrates of low degree of polymerization (DP) and low molecular weight composed of monosaccharides. Specific types of oligosaccharides, named non-digestible oligosaccharides, resist hydrolysis and absorption in the upper gastrointestinal tract, but can be fermented in the large bowel by gut bacteria. The structural factors of non-digestible oligosaccharides can affect the selective utilization and metabolites produced by gut bacteria. Therefore, some non-digestible oligosaccharides have prebiotic activity, which may promote human health by increasing populations of beneficial microbes and/or their metabolic activity. For this reason, industrial applications for non-digestible oligosaccharides have rapidly increased. The natural sources of non-digestible oligosaccharides cannot meet the high need for industrial applications, but they also can be obtained by either polysaccharide hydrolysis or enzymatic/chemical synthesis from disaccharide substrates. Both natural sources and commercial production of non-digestible oligosaccharides usually contain mixtures with different structures. The gut bacteria can cooperate with each other when they utilize non-digestible oligosaccharides, as they have different oligosaccharide digestive abilities, preferences and metabolic processes.