Chapter 45 - Exopolysaccharides produced by lactic acid bacteria in food and probiotic applications

Abstract

Microbial exopolysaccharides (EPSs) are polymers associated with the external cell surface, which can be covalently bound forming capsules, or are more loosely attached thereby developing a “slimy” layer. Exopolysaccharides (EPSs) produced by lactic acid bacteria (LAB) have received increasing attention in recent years because of their technological application in dairy products and their potentially beneficial properties for human health. Most of the EPS-producing LAB have been isolated from different fermented foods such as sourdoughs, sausages, table olives, cheeses, yoghurt, kefir, other fermented dairy products, and some traditional foods from nonindustrialized countries. Significant progress in the understanding of EPS synthetic pathways, genetics, kinetics of production, and structure–technological function relationships has been made in recent years. In recent years, EPSs from LAB are receiving a renewed interest because it has been claimed that they have benefits for human health, such as a cholesterol-lowering ability, a prebiotic effect and modulation of the immune response system. Nonetheless, most studies have been performed in vitro and there is a lack of clinical evidence demonstrating these putative probiotic characteristics after oral administration of EPSs in functional foods. In addition, the mechanism(s) and EPS-parameter(s) involved in these biological effects still remain poorly understood.