Volatile profile differences between spontaneous and cultivated Hyblean pasture

The Hyblean area is the major dairy producer of southeastern Sicily. This current study was undertaken to investigate the aroma-active compounds in order to detect any differences in the flavor profiles of two Hyblean pasture types of forage: cultivated vs. spontaneous. Forage samples were collected twice, at the beginning (Period I) and at the end (Period II) of April. Odor-Active Compounds (OACs) were extracted from the samples using a steam distillation technique. OACs were then detected and identified by gas chromatography/mass spectrometry/olfactometry (GC/MS/O) and grouped into 7 chemical classes: alcohol, aldehyde, ester, ketone, pyrazine, sulfur and terpene. The data was subsequently analyzed statistically by applying the Chi-square test, using a significant level of α = 0.05. Overall, forage samples from spontaneous pasture showed a significant difference higher (P < 0.01) in the number of OACs compared to those from cultivated pasture. Reflecting the growth trend in natural forage, OACs were higher in Period I compared to Period II in each pasture type, but was only significantly higher (P < 0.05) in the spontaneous pasture samples. In both pasture types, the chemical classes of OACs found were of significant difference, (P < 0.0001): alcohol, aldehyde, ketone and terpene classes presented a higher number of OACs compared to pyrazine, sulfur and not identified (NI) classes similar to esters. In conclusion, analysis of samples collected from spontaneous pasture revealed a richer odor profile than those from cultivated pasture, confirming that this type of forage is an important marker tied to the high Hyblean production area and possible influence on the aroma properties of milk and dairy products.