Dairy Industry Association of Australia

Fat plays a critical role in the flavour and flavour development of cheddar cheese. Fat reduction below 50% results in loss of desirable flavour and increased intensities of off-flavours. Removal of fat from an aged full-fat cheddar cheese demonstrates that nonpolar flavour-active volatiles remained in the cheese matrix rather than partitioning into the fat. Previous work has also demonstrated volatile compound profile differences between commercial full-fat and reduced fat cheeses. These studies collectively suggest that fat removal alters cheese biochemistry, resulting in distinct sensory flavour profiles rather than sensory effects solely due to partitioning and matrix effects. Recently, a replicated controlled study with full-fat, 50% and 83% fat reduced cheddar cheeses was applied to directly evaluate the impact of fat reduction on cheese flavour and flavour development. Flavour and volatile components of lowfat cheddar cheeses were distinct from full-fat cheeses (p<0.05). Decreases in fat content resulted in decreases in milkfat flavour, higher whey flavour and a decrease in the rate of aged cheese flavour development compared to full-fat cheeses. Sensory thresholds of isolated key compounds revealed greater than 100-fold increases for some compounds in a fat-based matrix (fullfat cheese) compared to a water-based matrix (83% fat reduced cheeses) (p<0.05). As a result, odour activity values for certain compounds including homofuraneol and phenylacetaldehyde increased in low-fat cheese compared to full-fat cheeses. These results demonstrate that fat reduction in cheddar cheeses alters volatile compound production as well as volatile compound release to collectively impact flavour perception.