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Exopolysaccharides from lactic acid bacteria- a world of opportunities
Exopolysaccharides (EPS) are polysaccharides secreted outside the cell wall of microorganisms. Exopolysaccharide-producing lactic acid bacteria are used to modify the textural and functional properties of fermented milk. The selection criteria of EPS-producing cultures depend on the desired physical properties of the fermented product. Exopolysaccharides provide functions that also benefit reduced-fat cheeses. They bind water and increase the moisture in the nonfat portion, reduce rigidity, and increase viscosity of the serum phase. Whey, the cheese byproduct, is concentrated or fractionated by membrane separation, and dried to produce a variety of products. The residual EPS in cheese whey have been demonstrated to enhance the functional properties of whey protein concentrate. On the other hand, application of EPS-producing cultures in cheese making may impact biofouling of whey filtration membranes. Exopolysaccharide can either enhance or prevent biofilm formation, depending upon their characteristics and interaction with the membrane surface. Fermented milks made with some EPS-producing strains have also shown chemopreventive effects against azoxymethane-induced tumors in rats. In conclusion, EPS from lactic acid bacteria can improve body and texture of dairy products and modify functionality of whey protein concentrates. As functional foods are gaining popularity, EPS as natural chemopreventive agents become an attractive choice.
Keywords: Lactic acid bacteria, Exopolysaccharides, Functionality, Dairy