Exopolysaccharides of Lactic Acid Bacteria: Functions and Research Methods

Most lactic acid bacteria synthesize exopolysaccharides during fermentation. Exopolysaccharides improve the stability and sensory profile of finished products by acting as thickeners or prebiotics. Exopolysaccharides are biologically active: they have antioxidant, immunomodulatory, and antitumor properties, as well as improve intestinal microbiota and reduce cholesterol. Polysaccharides of lactic acid bacteria meet the growing global demand for natural functional foods. Modern starter cultures can improve the sensory and rheological characteristics of the product. Exopolysaccharideproducing bacteria improve the quality of starter cultures. The nutrient medium composition (carbon, nitrogen, vitamins, minerals) and cultivation conditions (temperature, pH) affect the biosynthesis and yield of exopolysaccharides. They depend on the genus and species of lactic acid bacteria. Exopolysaccharides of lactic acid bacteria intensify dairy fermentation and reduce curd formation time, as well as stimulate the growth of associated probiotic microflora and the synthesis of beneficial metabolites. Studies of molecular composition and structure of exopolysaccharide-producing bacteria make it possible to explore the beneficial properties of polysaccharides, apply them in medicine, develop new functional starters, improve food quality, etc. This article reviews the most popular methods of exopolysaccharide studies, including their structure and monosaccharide composition.