Effect of exopolysaccharides produced by Lactobacillus sanfranciscensis on the processing properties of wheat doughs

The effect of crude exopolysaccharides (EPS) of Lactobacillus sanfranciscensis strains on processing properties of wheat doughs was investigated and compared to the commercial available hydrocolloids guar gum and xanthan using straight dough method. In addition, the effect of swelling process occurring during fermentation and of in situ formation of levan on dough and bread properties was determined. The doughs supplemented with levan showed higher water absorption and lower stickiness than those supplemented with guar gum and xanthan. However, F(max) and l(max) resulting from extensibility measurements as well as peak viscosity during gelatinization were less affected. The use of chemically acidified sponge doughs resulted in increased stickiness and changes in the extension properties of the wheat doughs with decreasing pH. These negative effects were compensated by the addition of crude levan extracts. Addition of sourdoughs markedly decreased their stickiness but not their F(max) and l(max) resulting from extensibility measurements, as compared with chemically acidified sponge doughs. Enhanced in situ production of levan increased dough stickiness as well as increased resistance and decreased extensibility. This effect could be traced back to an enrichment of sugar or metabolites due to an altered metabolism of the bacteria. Breads produced from straight doughs supplemented with levan showed higher volumes as compared to commercial hydrocolloids.