Optimization of dextran production by Leuconostoc mesenteroides in dairy fermented beverage

Some of lactic acid bacteria are able to produce extracellular polysaccharide through fermentation process. In the food industry, these polysaccharides are frequently used in beverages due to their water binding capacity and increasing viscosity. In addition to technological benefits, certain exopolysaccharides (EPS) have health effect on human, such as cholesterol lowering effect, immune-stimulatory effect and prebiotic activity. In this study, EPS (Dextran) production in dairy fermented beverage by leuconostoc mesenteroides and Synergistic efficacy of lactococcus lactis on dextran production have been investigated. Production of dextran in milk was optimized using response surface methodology with four independent factor, including: fermentation temperature (20-40 °C), fermentation time (15-35 hours), L.mesenteroides-L.lactis inoculation ratio (10:90 - 90:10) and percent of sucrose (0-6%).
According to the findings 20 °C, 20 hours, 4.5% sucrose and inoculation ratio of L.mesenteroides-L.lactis 50:50 was optimum condition for dextran production and the experimental results confirmed the predicted amount of dextran production in optimum condition.