# Evaluation of Garlic Landraces from Foggia Province (Puglia Region; Italy)
## 3 Results and Discussion
### Volatile Compounds
Apart from the genotype, other factors such as 'environment' may affect volatile compound concentrations, as widely proved in the specific literature on garlic [1; 33]. The large difference in concentration of (S)-volatile compounds between the CG and landraces could be imputable to different pre- and/or post-harvest management. It is well known that (S) fertilization is strictly correlated to the accumulation of garlic volatile S-compounds [34] and of organo-sulfur-compounds [35], precursors of volatile S-compounds [36]. The collected landraces might have accumulated lower (S) volatile compounds, probably due to the poor S availability in the marginal soils where these plants are collected, also characterized by a low organic matter content and no fertilizer application (in normal growing conditions various fertilizers are used containing significant amounts of sulfur, thus improving S availability). The different post-harvest storage time between the CG and landraces could have also affected their volatile (S)-compound contents. Several studies report that the concentrations of volatile [37] and non-volatile [38] S-compounds are higher in stored than in fresh material. The total amount of volatile (S)-compounds was lower than that found in other studies [4; 39]. The allicin in our landraces, representing less than 1% of the total volatile compounds and of the S-compounds, was slightly lower than that found in five endemic Italian varieties [6] and much lower than that found in red garlic from Argentinian germplasm [40] and in Croatian garlic [8]. The qualitative profile of the volatile component in the current study was instead in line with that found in numerous studies reported in the garlic literature [4; 32; 37; 39; 41; 42]. Genotype and/or 'environment' are also the main determinants of the composition of volatile compounds [1; 33]. In the current study, in the examined landraces the five most abundant S-compounds (representing 93% of the S-compounds) were 'di-allyl-trisulphide' (DATS) (0.67 mg kg\({}^{-1}\) dw; 32% of S-compounds), followed by 3-vinyl-1,2-dithyocyclohex-5-en' (0.47 mg kg\({}^{-1}\) dw; 23% of S-compounds), di-allyl-disulphide (DADS) (0.36 mg kg\({}^{-1}\) dw; 18%), 3-vinyl-1,2-dithiin (0.32 mg kg\({}^{-1}\) dw; 15%), and methyl-allyl-tri-sulphide (0.10 mg kg\({}^{-1}\) dw; 5%). The quantitative analysis in the CG showed that five compounds represented 85% of the total S-compounds: 3-vinyl-1,2-dithyocyclohex-5-ene (40% of the total), 3-vinyl-1,2-dithiin (18%), DATS (10%), and DADS (8%) and methyl-2-propenyl-di-sulphide (8%). The sulphide S-compounds were prevalent in the collected landraces, while the S-compounds belonging to the 'Vinyldithiins' family were prevalent in the CG. Although initially controversial, the S-compounds belonging to the 'Vinyldithiin' family are now considered the major components of fresh garlic and some of them have been found to have a very high flavour dilution factor (FD \(\geq\) 1) indicating an intense pungent odour [32; 43]. Accordingly, the CG should have a more pungent aroma than the collected landraces. It can be not excluded that the examined landraces were selected over the time as a conscious and intentional aim by growers to reduce the volatile (S)-compounds, responsible for breath and sweat smelling of garlic, which can last for days. Thus, landraces showed this drawback to a more limited extent.