Characterization of Maltese goat milk cheese flavour using SPME-GC/MS

The effect of lactation on the flavour of cheese made with raw milk of Maltese goats bred in Sicily (Italy) was studied. The goat cheese flavour was analyzed for the first time by Solid Phase Microextraction (SPME) coupled with Gas chromatography/Mass Spectrometry (GC/MS). The suitability of the analytical method was determined by calculating the coefficients of variation (CV%). Data were processed using ANOVA in relation to the stage of lactation. Forty four components (methyl ketones, free fatty acids, aldehydes, alcohols, esters, terpenes and lactones) were identified and quantified. The most representative fatty acids were butyric, baproic, baprylic and bapric (from 30 to 75% of the total identified fraction). Many other important cheese odorants were determined giving a substantial contribution to the aroma profile. The highest percentages were, for alcohols: isoamyl and phenethyl alcohols at the 2 month of lactation (6.82% and 2.81%, respectively); as regards ketones, at the 5 and 6 months of lactation: 2-heptanone (7.88% and 10.10%, respectively) and 2-nonanone (18.52% and 14.81%, respectively). The highest percentage of esters (2.5%) was found in the 7 month of lactation. The lactation significantly influenced the flavour components. Good CV percentages were obtained (less than 5.0). This easy and fast method permits a qualiquantitative description of the goat’s cheese flavour in relation to the lactation. The results testify the difficulty in attributing the variations to a single effect so as to standardize this product, even if this analytical method could help to give some indications, before marketing, regarding the consumer’s perception and acceptance. _______________________________________________________________________________________