Characterisation of pear distillates from wild and cultivated varieties in Sardinia

The aroma fraction of Italian distillates of wild (Pyrus amygidaliformis, Vill., namely ‘Pirastru’) and cultivated (Pyrus communis, L. cvs. ‘Coscia’, ‘Precoce di Fiorano’ and ‘Butirru de Austu’) pear varieties grown in the northern part of the island of Sardinia was investigated. Distillates from fermented mashes were obtained from the same producer and, in most cases, for 3 years following the same production process. Aroma analyses were performed by GC-FID and GC-MS techniques with direct GC injection of full proof distillates. Differences were found in the aromatic profile of all the distillates depending on their varietal origin. Wild Pirastru pear distillates were the richest in isoeugenol (0.186 g hL−1 a.a.), ethyl benzoate (0.388 g hL−1 a.a.) and ethyl phenylacetate (0.12 g hL−1 a.a.) but the poorest in 1-hexanol (2.69 g hL−1 a.a.), n-hexyl acetate (0.07 g hL−1 a.a.), Σ-farnesene isomers (0.80 g hL−1 a.a.) and citronellol (0.007 g hL−1 a.a.). Pirastru distillates were also the poorest in methyl and ethyl unsaturated decanoate isomers, the so-called Williams pear esters (0.002 g hL−1 a.a.). On the contrary, these compounds that characterise the aroma of Williams pear distillates were abundant in Coscia spirits (1.032 g hL−1 a.a.). The latter, together with Precoce di Fiorano, were rich in farnesene isomers (6.48 and 9.26 g hL−1 a.a. respectively). Evaluation of the data by univariate (anova and Kruskal–Wallis) and multivariate (PCA and HCA) statistical analyses revealed that some components (the classes of acetates, farnesene isomers, methyl and ethyl unsaturated decanoate esters and citronellol) are relevant in discriminating the distillates according to variety.