Biochemical and molecular profiling of unknown olive genotypes from central Italy: determination of major and minor components

Abstract

The phenotypic and genetic variability of local olives in a perspective of diversity conservation should be maintained and preserved. Fourteen unknown olive genotypes were selected from abandoned and isolated plants in Umbria region and characterized by ten SSR markers. The molecular analysis led to identify ten previously unknown genotypes within the patrimony of the region, made up by about 10 main cultivars and more than 100 minor ones. Fruit samples were randomly collected from the selected plants during two growing seasons and oil was extracted from each sample. Analyses of fatty acid composition, phenolic profile (flavonoids, phenolic acids, phenolic alcohols and lignans), tocopherols, squalene and sterols were performed on these oils. Significant differences were observed in terms of main fatty acids (e.g. oleic acid from 71.83 to 76.73%), but not for the minor ones. The important differences were instead obtained on the amount of α-tocopherol, ranging from 149 to 583 mg kg−1, and on squalene, spanning from 1059 to 5447 mg kg−1. Evaluation of major and minor compounds with the principal component analysis of the main oil quality parameters revealed differentiation according to the genotypes. The analysis of neglected olive genotypes from a small area of cultivation has led to the identification of a promising source of variability for most sought-after traits, which could be exploited for new olive plantations and to magnify the spectrum of local olive oils.