mannans

Mannans are polysaccharides composed predominantly of mannose units. They form a diverse family of polymers with backbones of β-1,4-linked mannose residues, and many members bear side chains or include other sugars. The major types are galactomannans, glucomannans, and plain mannans. Galactomannans have galactose side chains attached mainly at the O-6 position of mannose units; common examples include guar gum and locust bean gum. Glucomannans are copolymers of glucose and mannose with β-1,4 linkages, such as konjac glucomannan. Plant and fungal mannans occur in hemicelluloses and on cell surfaces, while yeast and fungal cell walls incorporate mannans in glycoproteins.

Natural occurrence: In plants, mannans are components of hemicelluloses in seeds, wood, and other tissues. In yeasts and fungi they form abundant mannoprotein layers on the cell wall. The structure influences solubility and viscosity, with galactomannans generally being highly soluble and effective as thickeners.

Applications: Mannans are used as thickening and stabilizing agents in foods and beverages, as well as in cosmetics and pharmaceuticals. They serve as dietary fiber and can have prebiotic effects, contributing to gut health. Industrial uses include paper and textile processing due to their rheological properties, and they are valued for biodegradability and compatibility with other ingredients.

Nutrition and digestion: Humans lack most enzymes to hydrolyze β-1,4-mannan backbones; mannans are partially fermented by gut microbiota, producing short-chain fatty acids and gas. Degradation is aided by microbial endo-β-mannanases and β-mannosidases. Safety: generally regarded as safe at typical dietary and industrial usage levels.