Isolation of yeast strains from Chinese liquor Daqu and its use in the wheat sourdough bread making

Abstract

Two yeast strains, Meyerozyma guilliermondii EH1 and Pichia kudriavzevii EP1, together with Lactobacillus sanfranciscensis DSM20451T were used as mixed starter cultures on sourdough bread making. Both yeast strains isolated from Chinese liquor Daqu were selected among 79 isolates by primary sensory evaluation of bread and growth test with L. sanfranciscensis during sourdough fermentation. High growth rate, resistance to acid and osmotic pressures were observed for both yeast strains. In presence of L. sanfranciscensis, M. guilliermondii EH1 and P. kudriavzevii EP1 exhibited higher growth rates and yields in wheat flour sourdough. Production of organic acids, specific loaf volume, crumb texture, crumb colour, staling rate, and volatile composition of the sourdough bread was evaluated. The results showed that the use of isolated yeast strains led to the higher accumulation of esters, aldehydes and other aroma compounds. Our findings demonstrated improved flavour complexity and increased consumer acceptance of bread using mixed starters.