INTERACTION BETWEEN LACTIC-ACID BACTERIA AND YEASTS IN SOUR-DOUGH USING A RHEOFERMENTOMETER

Rheofermentometer assays were used to characterize the leavening of sour-doughs produced using species of lactic acid bacteria (LAB) and yeasts, alone or in combination, Saccharomyces cerevisiae 141 produced the most CO2 and ethanol whereas S, exiguus M14 and Lactobacillus brevis subsp, lindneri CBI contributed poorly to leavening and gave sour-doughs without porosity, In comparison with that seen in sour-dough produced with yeast alone, yeast fermentation with heterofermentative LAB present was faster whereas that with homofermentative LAB (L. plantarum DC400, L, farciminis CF3) present was slower and produced more CO2, Combining L, brevis subsp, lindneri CBI with S, cerevisiae 141 decreased bacterial cell numbers and souring activity. However, addition of fructose to the sour-dough overcame these problems as well as activating S, cerevisiae 141.