METABOLISM OF YEASTS AND LACTIC-ACID BACTERIA DURING DOUGH FERMENTATION RELATING FUNCTIONAL-CHARACTERISTICS OF FERMENTED DOUGHS

Properties of fermented wheat doughs inoculated with compressed yeast and pure and associated cultures of Saccharomyces cerevisiae and Lacto bacillus brevis, Lactobacillus plantarum and Enterococcus faecium were studied. Samples with yeast and samples without yeast (including unin oculated doughs) were clustered separately. As a general trend, the mo re heterogeneous the starter, the better the functional characteristic s. Differences during the fermentation step in contents of low molecul ar nitrogen metabolites (peptides and amino acids) were analysed. Star ters were categorized in two groups depending on the presence of yeast (with a net uptake of these metabolites) or the absence of yeast (wit h net accumulation) on the basis of their metabolism during fermentati on. Relationships between functional and biochemical parameters were e stablished in order to determine the dependency between starter metabo lism and technological quality. Results evidenced some good correlatio ns between energy, extensibility, volume, oven rise and elasticity, an d the changes in free amino acid and peptide contents during proofing under the experimental conditions used.