A comparative study of the semiquantitative analysis of volatile compounds in Hispánico cheese

Abstract

Hispánico cheese is a semi-hard Spanish variety manufactured from a mixture of cows' and ewes' milk. Up to 46 compounds have been identified in its volatile fraction by means of a purge and trap apparatus coupled to gas chromatography-mass spectrometry. The coefficients of variation between duplicate determinations of the concentrations of 20 selected compounds in 48 cheese samples expressed as peak areas and as relative abundances referred to cyclohexanone and camphor, used as internal standards, were compared. The coefficient of variation of the method (peak area) ranged from 5 to 20% for the majority of the volatile compounds. After paired observations comparison of means, the coefficients of variation of 8 compounds were significantly lower for peak areas and relative abundances to cyclohexanone than for relative abundances to camphor. In the case of ethanol coefficients of variation were significantly lower for peak areas, whereas in the case of 2-pentanone they were significantly lower for relative abundances to cyclohexanone. For the other 10 compounds no significant differences between coefficients of variation were recorded. Means of coefficients of variation for the selected 20 volatile compounds in the 48 samples were 15.05, 15.89 and 17.34% for peak area, relative abundance to cyclohexanone and relative abundance to camphor, respectively.