Identification of Volatile Off-flavors in Reduced-fat Cheddar Cheeses Containing Lecithin

Volatile components of 6 mo. 33% reduced-fat Cheddar cheeses and reduced-fat cheeses containing deoiled granular soy lecithin, ca 2 g/100 g of cheese, were isolated by vacuum distillation-solvent extraction. Extracts were separated into neutral/basic and acidic fractions. Volatile constituents in each fraction were analyzed by gas chromatography/olfactometry and gas chromatography/mass spectrometry. A side-by-side comparison of neutral/basic fractions from the two cheeses revealed many alkanals, alkenals, and dienals present when the lecithin was added. Among these, (E,E)-2,4-nonadienal (fatty/sweet), (E,Z)-2,4-decadienal (corn chip/stale/hay), (E,E)-2,4-decadienal (fatty/fried), and (E)-2-nonenal (stale/bitter) were detected at high odor intensities. Based on the quantitative data, (E,Z)-2,4-decadienal and (E,E)-2,4-decadienal were the main compounds contributing to the off-flavors in reduced-fat Cheddar cheeses when lecithin was added.