Identification of volatile off-flavors in reduced-fat cheddar cheeses containing lecithin

Volatile components of 6 mo. 33% reduced-fat Cheddar cheeses and reduced-fa t cheeses containing deoiled granular soy lecithin, ca 2 g/100 g of cheese, were isolated by vacuum distillation-solvent extraction. Extracts were sep arated into neutral/basic and acidic actions. Volatile constituents in each fraction were analyzed by gas chromatography/olfactometry and gas chromato graphy/mass spectrometry. A side-by-side comparison of neutral/basic fracti ons from the two cheeses revealed many alkanals, alkenals, and dienals pres ent when the lecithin was added. Among these, (E,E)-2,4-nonadienal (fatty/s weet), (E,Z)-2,4-decadienal (corn chip/stale/hay), (E,E)-2, 4-decadienal (f atty/fried), and (E,E)-2-nonenal (stale/bitter) were detected at high odor intensities. Based an the quantitative data, (E,Z)-2, 4-decadienal and (E,E )-2, 4-decadienal were the main compounds contributing to the off-flavors i n reduced-fat Cheddar cheeses when lecithin was added. (C) 1999 Academic Pr ess.