Changes in fatty acid composition of various lipid components of Zygosaccharomyces rouxii as influenced by solutes, potassium sorbate and incubation temperature.

The effects of water activity (aw), solutes, potassium sorbate and incubation temperature on the fatty acid methyl ester composition of the total extracted lipid, triacylglycerol, phospholipid, free fatty acid and steryl ester components of Zygosaccharomyces rouxii were determined. Oleic (C18:1) and linoleic (C18:2) acids were the major components of the total fatty acid fraction, regardless of culturing conditions. Cells grown at 35 degrees C contained a significantly higher percentage of C18:1 and a lower percentage of C18:2 than did cells grown at 21 degrees C. At both temperatures, cells cultured in low-aw (0.93) media contained a significantly higher percentage of C18:1, with a corresponding decrease in C18:2 content than did cells grown at aw 0.99, regardless of the addition of glucose, sucrose, or NaCl to suppress the aw. At 21 degrees C, cells cultured in high-aw (0.99) media supplemented with 300 micrograms sorbate per ml contained higher percentages of C18:1 than did cells cultured in media not supplemented with sorbate. Cells grown at 35 degrees C in low-aw media supplemented with sorbate contained substantially more C18:1 than did cells cultured without sorbate.