Changes in flavour and volatiles of full-fat and reducedfat Cheddar cheeses during maturation

Abstract

To determine why reduced-fat (7% fat) Cheddar cheese does not develop full Cheddar flavour, volatiles from four manufactures of full-fat Cheddar (conventional and made by an ultrafiltration process) and reduced-fat Cheddars (1.5 and 2% salt, also made by the ultrafiltration process) were compared at intervals over a 26-week period of maturation. Molecular distillates and headspace volatiles were examined by gas chromatography/mass spectrometry. Headspace volatiles were also analysed for sulphur compounds by gas chromatography with a flame photometric detector. Full-fat cheeses consistently had more flavour than reduced-fat cheeses. For each type of cheese the rate of production of dimethyl sulphide became progressively less as the season advanced from lush spring pastures to dry summer pastures. Overall, there was a steady increase with time of maturation in the level of H 2 S while the concentration of methanethiol rose for the first 8 weeks and then levelled off. The concentration of sulphur compounds in the headspaces was greater generally for the reduced-fat cheeses than for the full-fat cheeses, but when partition coefficients are taken into consideration, the actual concentration of methanethiol in the reduced-fat cheese was about half that in the fullfat cheese. There was a correlation of 0.82 between the intensity of Cheddar flavour and the concentration of methanethiol in the cheeses, indicating that a lack of methanethiol in the reduced-fat cheeses was a major contributor to their lack of flavour. A combination of methanethiol and decanoic acid or butanoic acid in all cheeses gave a better correlation with Cheddar flavour than methanethiol alone.