Homooligosaccharides

Homooligosaccharides are oligosaccharides composed entirely of a single type of monosaccharide residue. They typically contain two to about ten sugar units (degree of polymerization, DP), though longer oligomers can occur in some contexts. This contrasts with heterooligosaccharides, which consist of more than one monosaccharide species.

Common examples include cello-oligosaccharides, which are built from glucose units linked by β-1,4 bonds; chito-oligosaccharides, from N-acetylglucosamine with β-1,4 links; galacto-oligosaccharides, formed from galactose units with various β-linkages; xilo-oligosaccharides, based on xylose with β-1,4 connections; and manno-oligosaccharides, composed of mannose units with β-1,4 linkages. The precise linkage and DP influence properties such as solubility, digestibility, and fermentability.

Natural occurrence and production methods: homooligosaccharides arise from partial hydrolysis of larger polysaccharides such as cellulose, chitin, xylan, galactan, or mannan, and can also be produced by targeted enzymatic breakdown using glycosidases or by controlled acid hydrolysis for research or industrial use.

Properties and applications: because they consist of a single sugar type, most homooligosaccharides are not readily digested by humans and can contribute dietary fiber-like effects. They are used as prebiotic ingredients, texture modifiers, or carriers in food, pharmaceutical, and cosmetic formulations. Their simple composition also makes them useful reference standards in structural and analytical studies.

Analytical considerations: characterizing homooligosaccharides typically involves determining DP distribution and glycosidic linkage types, using techniques such as high-performance liquid chromatography, mass spectrometry, and nuclear magnetic resonance spectroscopy, often complemented by enzymatic digestion profiles.