Exopolysaccharides from lactic acid bacteria: Technological bottlenecks and practical solutions

Microbial exopolysaccharides are added to or occur in a wide variety of food products, where they serve as viscosifying or gelling agents. Exogolysaccharides with different composition, size and structure are synthesized by several strains of lactic acid bacteria. Structural analyses combined with rheological studies reveal that there is considerable variation among the different exopolysaccharides; some of them exhibit remarkable thickening and shear-thinning properties and display high intrinsic viscosities. Hence, several slime-producing lactic acid bacterium strains and their biopolymers have interesting functional and technological properties, which may be exploited towards different products. However, the production of exopolysaccharides from lactic acid bacteria is low and often unstable, and their downstream processing is difficult. Strain improvement, enhanced productivities and advanced modification and production processes (both enzyme and fermentation technology) may contribute to their economic soundness.