The sourdough microflora - Microbiological, biochemical and breadmaking characteristics of doughs fermented with freeze-dried mixed starters, freeze-dried wheat sourdough and mixed fresh cell starters

Freeze-dried mixed starters, freeze-dried wheat sourdough and mixed fresh-cell starters made with Lactobacillus sanfrancisco CBI, L. plantarum DC400 and. Saccharomyces cerevisiae 141 and/or S. exiguus M14 were used for leavening wheat doughs, and their microbiological, biochemical and breadmaking characteristics were compared with those of Italian traditional doughs produced by baker's yeast. All the doughs fermented with starters had more balanced microbiological and biochemical characteristics than dough started with baker's yeast in which alcoholic fermentation end-products largely predominated. By using starters, the greatest lactic acid bacteria cell number and acetic acid production, were achieved, along with more complete profiles of volatile compounds and greater structural stability of fermented doughs. Fresh-cell starters showed higher microbial functionality and represented the only way to enrich the doughs with S. exiguus M14, some of which survived the freeze-drying process. No differences were detected between the two different types of freeze-dried starters and the subsequent use (10 times) of doughs initially produced with freeze-dried starters eliminated initial differences in the microbial functionality with respect to fresh-cell starters.