Production of Microbial Exopolysaccharides

Abstract: It is well know that the use of surdough is essential for rye bread making. Some bacterial starter cultures have the abilities to synthesize the homoexopolysaccharides (HoPS) in sourdoughs. The HoPS improve the texture, quality and shelf life of bread, and are known to have prebiotic behavior. The aim of our study was to investigate the abilities of six starter strains of lactic acid bacteria (LAB) to produce HoPS in sourdoughs. Four starter strains from MIUG collection Weissella confusa (UGAL1), Lactococcus lactis ssp. Lactis (UGAL2), Lactobacillus plantarum (15GAL), Lactobacillus brevis (16GAL), and two comercial strains Lactobacillus plantarum and Lactobacillus brevis (DI-PROX MTTX) and Lactobacillus helveticus (LH-B02), were used. The sourdougs were prepared using whole meal rye; the dough yield was 300. After 20 hours of fermentation at 37°C the HoPS were separated, and after acid hydrolysis the monosaccharides were quantified using enzymatic UV method, and by high-performance liquid chromatography. The total water-soluble polysaccharides content from sourdough was determined by phenol-sulfuric acid method. Excepting the 15GAL and 16GAL strains, all other tested LAB are HoPS-producing. The levels of HoPS ranged between 0.88 to 1.75 mg/g of whole rye flour