BIOCHEMICAL AND TECHNOLOGICAL CHARACTERISTICS OF FROZEN MICROBIAL CONCENTRATES FOR BREADMAKING

Three microbial starters were formulated from different combinations o f pure cultures of yeasts and lactobacilli: A (Saccharomyces cerevisia e, Lactobacillus brevis and L. plantarum), B (S. cerevisiae. S. fructu um and L. brevis), and C (S. cerevisiae, Candida boidinii and L. plant arum), and a fourth including commercial dry yeast and both lactobacil li D. Biomass of each mixture was frozen, to obtain frozen concentrate s that were inoculated afterwards to wheat flour doughs. The quality o f the starters was determined on the basis of: biochemical characteris tics (organic acids and sugars), technological properties (pH, total t itratable acidity, gassing power, extensigram, maturogram and impulsog ram), and breadmaking quality (bread volume, pH, total titratable acid ity and acids and sugars contents of breads, and sensory analysis). Sa mples A and D showed very similar gassing power, rheological propertie s and breadmaking quality. In every case values pointed to a higher fe rmentative activity and technological quality than those observed with the other concentrates (samples B and D). No differences among sample s were noticed for pH and total titratable acidity of doughs and bread s, nor in organic acids or sugars contents. However, sample C, contain ing C. boidinii, showed different trends in sugar consumption, and a s ynergistic effect on acidification ability of dough when compared with the activity shown by each yeast strain.