Analysis of biotechnological processes during the maturation of rye sourdough based on probiotic microorganisms

Probiotic sourdough starters for bakery production influence biochemical processes during the ripening of semi-finished products, enrich bread with valuable nutrients, influence its taste, flavor, prolong shelf life. The aim of the work was to investigate the biotechnological properties of liquid rye sourdough starter with probiotic microorganisms of the genus Bifidobacterium. The research objects were samples of rye sourdough starter prepared according to the Leningrad scheme and rye flour sourdough starter prepared on the basis of Bifidobacterium concentrate and yeast S. Minor. Fermentation of sourdough starter was carried out at temperature regimes - 37 and 42 °C. By changing the temperature parameters of fermentation, it is possible to intensify the processes of accumulation of acids and carbon dioxide, reduce the duration of sourdough maturation. Bifidobacteria-based sourdough, most actively accumulates acidity at 42 °C, reaches a titratable acidity of 10.8 °H after 4 hours, accumulates up to 85 mg/mL of lactic acid, while the Leningrad sourdough is most actively ripening at 27 °C. Sourdough samples B-42 and B-37 were characterized by the best values of the lifting power after 4 hours of fermentation. At fermentation temperature of 42 °C, the viscosity of sourdough starter was the highest and reached values of 165-170 Pa*s. Microscopy of mature sourdough starter based on bifidobacteria revealed clusters of bacilliform curved bacteria variously shaped. In Leningrad sourdough cultures both bacilliform lactococci and streptococci, clusters of yeast cells were observed. The results proved that by changing the composition of microorganisms in sourdough and fermentation temperature, it is possible to effectively manage the rate of sourdough maturation, intensify the accumulation of organic acids and carbon dioxide. The quality of rye sourdough based on bifidobacteria is technologically comparable to the quality of traditional sourdough based on cultures of lactic acid bacteria.