Dextrans have great potential for applications in various food products as conditioners, stabilizers, bodying agents or related uses. They are used in confectionery for improvement of moisture retention, viscosity, and inhibition of sugar crystallization. In gum and jelly candies they are used as gelling agents. In ice cream they are applied as crystallization inhibitors, while in pudding mixes they provide the desirable body and mouthfeel (Whistler and Daniel, 1990; Day and Kim, 1993; Jallali, 2003; Khan et al., 2007). Different ester and ether derivatives of dextran furnish macromolecules with diverse properties and negative, positive, or neutral charges. Dextran has gained wide application in the food industry. Innumerable applications of dextrans in food applications were patented in the 50’s and 60’s (Glicksman, 1982; de Belder, 2003). Dextrans are considered as safe as components of food packaging materials. Dextran can be also used as a non-active ingredient in pharmaceutical formulations. Dextran is an unusually flexible polysaccharide that promotes high solubility and low solution viscosities, its behavior would not be expected to conform to traditional food uses (Whistler, 1973). Dextran could be suitable for certain food use application not associated with thickening or gelling functionalities. Examples include use as a source of dietary fiber, as a cryostabilizer and fat substitute in frozen food systems, as a flavor carrier in fluid foods or as a low calorie bulking agent for sweeteners (McCurdy et. al., 1994).
In food products dextran increase the dietary fiber content and can be used as viscosifiers, stabilizers, emulsifiers or gelling agents to improve physical and structural properties of water and oil holding capacity, viscosity, texture, sensory characteristics and shelf-life.
Over the past few decades, interest in using microbial EPSs – as dextran – in food processing has been increasing because of main reasons such as easy production, better rheological and stability characteristics, cost effectiveness and supply. Dextran also plays a crucial role in conferring beneficial physiological effects on human health, such as the ability to lower pressure and to reduce lipid level in blood. Furthermoredextran exhibits antitumor, immunomodulating, antioxidant and antibacterial properties. The utility of various biopolymers are dependent on their monosaccharide composition, type of linkages present, degree of branching and molecular weight. In the present chapter, an attempt was taken to recapitulate the most important polysaccharides isolated from microorganisms as well as the main methods for microbial exopolysaccharide production, purification and structural characterization. In addition, the functional and healthy benefits of dextran and its applications in food industry were described.