The Effect of Low Temperature Storage on the Lipid Composition of Baker\u27s Yeast

Production of frozen dough demands the usage of freezing/thawing resistant strains of baker\u27s yeast that can adapt to low temperature and preserve fermentative performance, which is closely related to the lipid composition of their cells. In order to determine the effect of low temperature storage on the baker’s yeast, we have analysed lipids of compressed commercial baker’s yeast of Saccharomyces cerevisiae strain maintained at 4 °C (7 and 14 days) and -20 °C (7, 14 and 120 days). In the phospholipid composition of all groups the most abundant was phosphatidylcholine (42 – 56 % of total phospholipids), followed by phosphatidylinositol (21 – 28 %). Phosphatidylcholine to phosphatidylethanolamine ratio, one of the parameters of the adaptation capability to extracellular changes, was high (2.4 – 3.3). Sterol esters and ergosterol were the most abundant neutral lipids in all groups. Oleic and palmitoleic acids were by far the most abundant fatty acids in all groups (39 – 48 % and 33 – 38 % of total cell fatty acids, respectively). Compared to the fresh yeast, considerable differences were found in the composition of all three lipid classes in the samples maintained at both temperatures. The major changes were observed after 14 days of exposure to -20 °C