Microbial Exopolysaccharides: A Review of Their Function and Application in Food Sciences

Extracellular polymeric substances are defined as high molecular weight compounds secreted by the microorganisms in the surrounding area. Since these extracellular substances are mainly polysaccharide, they are named exopolysaccharide. Microbial exopolysaccharides as high molecular weight polymers, composed of sugar residue have growing interest as a new class of microbial products which can be used in food, pharmaceutical, and biomedical industries. Microbial derived exopolysaccharides are considered as either good substitute of other synthetic or natural polymers or novel biopolymers which are used in food for thickening, suspending and gelling function. Although, microbial derived compounds have a versatile reputation and the numbers of published articles in this area are increasing, only three exopolysaccharides xanthan, gellan and dextran have been survived the industrial competition. Regarding the importance of these three ones, they have been discussed in detail in this paper. In this review article, the function and application of microbial exopolysaccharides are discussed regarding their physical properties and chemical structure.