Interaction of non-culture microbial flora on dough fermentation

Abstract

The interaction between the microbial flora associated with the bread baking process was investigated. The fermentative abilities of each of the different microbial genera isolated from bread dough, were compared by means of carbon dioxide production in a fermento-manometer by adding a corresponding proportion (similar to normal dough) of living cells to pre-sterilized bread dough. The behaviour of the different bacteria and yeast genera (with the addition of a commercial culture of Saccharomyces cerevisiae) was evaluated under standard conditions. The fermentative ability of the yeast strain Saccharomyces cerevisiae (CSIR-Y2) in bread dough, was used as reference to determine the contribution of the non-culture organisms to fermentation. The Gram-positive bacteria had a stimulatory effect on fermentation, while the Gram-negative bacteria inhibited fermentation. The addition of Lactobacillus spp. and wild species of the genus Saccharomyces resulted in the most significant improvement in the performance of carbon dioxide production. The cumulative effect of a mixture representing all the microbial flora usually encountered in bread dough, however, also resulting in an increase in fermentation ability. For purposes of optimizing fermentation and obtaining optimum taste, texture and shelf-life of bread, the goal, however, should be to decrease the number of undesirable organisms.