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.
Nextdext® Improves freshness, mouthfeel, softness, crumb texture, loaf volume and shelf life (instead of adding additives).
Dextran-containing sourdough allows to get additive-free bread of high quality. Effect of dextran, weak acidification and the association on gluten dough structure, thermal properties and rheology are improved by the associated dextran.
The incorporation of dextran in bakery products improves yields of production, softness and crumb texture of the final product. The addition of 2% native dextran increases the water absorption of flour dough by about 12% (both, in presence or absence of gluten).
William et al. (1959) reported that dextran displayed unique effects on dough mixing properties.
- Effects of dextran, weak acidification and their combination on starch retrogradation revealed the underlying mechanisms.
Weak acidification is fundamental for the improvement of high Mw dextran on dough elasticity. Recent studies underline that Dextran decreased moisture migration due to high water-binding capacity. Enhancements of amylose aggregation by weak acidification contributed to retardation of amylopectin recrystallization. Dough rheology demonstrated that weak acidification brings to dextran-induced positive dough viscoelasticity. This study indicates a combined anti-firming performance of high Mw dextran and weak acidification, to prolong shelf life of wheat bread.
Celiac disease is an autoimmune, nutrient-induced disorder, triggered in genetically susceptible individuals by ingesting gluten from wheat, rye, barley, and other closely related cereal grains (Goggins and Kelleher 1994). Celiac disease is a major health problem affect around 1% of population in the western world (Mustalahti et al. 2010). Gluten is an important protein-building structure, which contributes to appearance and crumb structure in many bakery products. The replacement of gluten in bread presents a significant technological challenge due to the low nutritional quality, poor sensory characteristics such as dry crumb, poor mouth feel, and off flavors of gluten-free products (Galle et al. 2012; Hager and Arendt 2013). Hydrocolloids are currently used to substitute gluten and to obtain gluten-free bread with acceptable sensory properties (Galle et al. 2010; Hager and Arendt, 2013). Incorporation of sourdough to a gluten-free formula gained interest recently in bread making. Dextran improves dough rheology and bread texture and can be used to replace non-bacterial hydrocolloids, such as guar-gum and hydroxypropyl methylcellulose for the generation of gluten-free soft bread with goodtexture and longer shelf life (Tieking and Ganzle 2005; Galle et al. 2012). Dextran holds potential application in baking industry for the generation of gluten-free food products for patients suffering from celiac disease (Schwab et al. 2008; Galle et al. 2010; Rao and Goyal 2013).
Nextdext® Improves moisture retention and viscosity; inhibits sugar crystallization and as gelling agent in gum and jelly candies. Dextran is used for maintaining flavor, viscosity, moisture, inhibition of sugar crystallization, and asgelling agent in gum and jelly candies in confectioneries (Maina et al. 2011). It is also used in softdrinks, flavor extract, milk beverages, and icing.
Nextdext® Increases viscosity and creaminess; reduces syneresis. The texture of yogurt and yogurt-like products made from milk by fermentation with LAB can be modified by in situ production of EPS (Cerning 1995; Tamime and Robinson 1999). EPS produced by LAB, particularly dextran, positively affected the rheological properties of acidified milk gelswith enhanced viscosity, creaminess, and reduced syneresis because of its water-binding ability (Mende et al. 2013) and hence can replace the commercially used texturizers, xanthan, carrageenan, pectin, guar gum, and b-glucan.
Cryoprotectant (Naessens et al. 2005). Dextran is bland and nontoxic; it is considered to have many advantages over other ice cream stabilizers. Ice cream mixes containing 2–4 % dextran conferred beneficial properties on viscosity (Bhavani and Nisha 2010).
Protection from oxidation and chemical changes and preservation in texture and flavor. The favorable properties of dextran for stabilizing vacuum, air-dried, and freeze-dried or frozen foods enable the use of dextran in fish products, meat, vegetables, and cheese. A fi lm of dextran could protect food from oxidation and other chemical changes and also help to preserve texture and flavor. The increasing demand for fast food in frozen or dried state creates an opportunity for the use of dextran as a preservative, as well as a texture, flavor, and smell enhancer (Bhavani and Nisha2010).
Improves water binding and increases moisture content in the non-fat substances. Reduced-Fat Cheese: The fat reduction in cheese results in many textural and functional defects. The high casein content in reduced-fat cheese imparts a firm and rubbery body and texture. Dextran is a good candidate for making reduced-fat cheese for several reasons. Dextran has the ability to bind water and increase the moisture in the non-fat mass (Awad et al. 2005).
The bacterial exopolysaccharides (EPS) have interesting film-forming properties and may be used to produce edible packaging, as a structural enhancer, a bioactive agent or probiotic carrier in edible films and coatings. In these days, there is a specific demand for food products with reduced addition of artificial additives and from renewable sources, and the EPS- especially dextran – meet these criteria with additional bioactive functions, like antioxidant and antimicrobial activities. This makes dextran good choice for the production of edible food packaging, which highlight the need of investing in this study area.
