Morphological characterization and composition of essential oils of Pompia selection, a citrus typical of Sardinia

Pompia is a citrus fruit belonging to the Rutaceae family, widespread almost exclusively in Central-Eastern Sardinia. The origins are not yet completely clear, but it seems that it comes from a hybridization of cedar, lemon and bitter orange. In Sardinia it is mainly used in the confectionery industry for the production of typical sweets and for the production of pompia liqueur. In this work we wanted to deepen the knowledge related to this species by analyzing and characterizing a selection grown in the Biodiversity center located in Surigheddu (SS). Using the pomological data sheets for citrus germplasm, it was possible to catalog the fruits of this selection, which was named ‘Surigheddu’. The following parameters were used for the classification: skin color, shape of the fruit, weight of the fruit, diameter and height of the fruit, thickness of the skin and of the albedo, presence or absence of roughness in the epicarp, the shape of the base and apex of the fruit, the number of seeds, and number of segments. For each replication, the juice yield (%), the content of Total Soluble Solids (°Brix) and the total acidity (%) were determined. In addition, the essential oil of leaves and berries was extracted by hydro-distillation, subsequently, gas chromatographic analysis coupled with mass spectrometry made it possible to trace the composition of the same. The morphological analysis of the fruits showed the presence on the plants of large fruits characterized by sometimes wrinkled and sometimes smooth epicarp, the high acidity of the juice was confirmed. The results showed that the essential oil of the leaves contains a high percentage of geranial (27%), neral (15%) and limonene (12%). While the essential oil of flavedo was made up of 90% limonene.