589. A chemical investigation of the volatile flavour principle of Cheddar cheese

Diacetyl, acetoin, 2,3-butyleneglycol, 2-butanone and 2-butanol concentrations in ripening Cheddar cheese

Diacetyl, acetoin, 2,3-butyleneglycol, 2-butanone and 2-butanol concentrations have been determined in ripened Cheddar cheese made usingStreptococcus diacetilactisDRC1 orStr. cremorisAM2or HP as starter culture. Diacetyl content was found to be initially higher in the DRC 1 cheese than in the other 2 cheeses, presumably because this starter readily ferments citrate. The disappearance of acetoin appears to be related to the formation of 2,3-butyleneglycol in DRCl and AM2cheeses, but not in HP cheese. Only trace amounts of 2-butanone and 2-butanol were observed in the 3 cheeses even though the concentration of a postulated precursor, 2,3-butyleneglycol, was present in considerable concentration in the DRC1 and AM2cheeses. Analysis of a number of mature AM2and HP cheeses selected at random indicated the presence of 2-butanone in only a few of the AM2cheeses. It is suggested that this compound may have arisen from the presence of a micro-organism which entered the cheese vat at the time of cheese-making.

Some volatile compounds in New Zealand Cheddar cheese and their possible significance in flavour formation: I. Identification of the volatile carbonyl fraction

Flavour concentrates from mature New Zealand Cheddar cheese were prepared by steam distillation methods. Using 2:4-dinitrophenylhydrazine reagent the presence of carbonyl compounds in the distillate was established. By means of paper chromatography, and other methods, the following compounds were identified in the distillate: acetoin, diacetyl, acetaldehyde, acetone, 2-butanone, 2-pentanone, 2-heptanone, 2-nonanone and 2-undecanone, and their approximate concentrations in New Zealand Cheddar cheese were determined. The possible role of these compounds in the formation of Cheddar cheese flavour is discussed.

The authors gratefully acknowledge the helpful advice and criticism of Dr H. R. Whitehead and Dr W. A. McGillivray, and the technical assistance of Mr P. L. McLaughlin.