Synergistic effects of the biological and chemical preservatives in dough fermentation

Increasing the shelf life of bread and food security can be achieved through biological (sourdough fermented by microbial strains with inhibitory activity), chemical (calcium propionate, essential oils), and physical (packaging system) methods. There were evaluated the synergistic effects of rye sourdough fermented by Lactobacillus plantarum (strains C71, C78 and C81) and calcium propionate or essential oils (onion, garlic, oregano) on the fermentation of the wheat dough. In relation to the flour amount, preservatives were used in percentage of 0.2% (w/w) for the rye sourdough, 0.1% to 0.2% (w/w) for calcium propionate and 0.1% (v/w) for essential oils. Microbiological (lactic acid bacteria and yeasts), biochemical (pH, total titrable acidity, lactic and acetic acids) and molecular genetics of Lactobacillus plantarum strains testing were performed on bread dough. Microbiological analysis of wheat dough with adding of rye sourdough and calcium propionate or essential oils showed that they do not substantially alter the viability of lactic acid bacteria and yeast strains. Genetic and biochemical stability of C71, C78 and C81 strains of Lactobacillus plantarum, as well as their proportion were not affected by calcium propionate or essential oils. Calcium propionate had an antifungal effect stronger than onion, garlic and oregano essential oils.