Change in quality during ripening of olive fruits and related oils extracted from three minor autochthonous Sardinian cultivars

Abstract

Ripening stage is one of the key factors in determining quality of olive fruits and related oils. This research, thus, was aimed to study the influence of three different harvesting times on the quality parameters of olives and related oils of three autochthonous Sardinian cultivars, Sivigliana da olio, Semidana, and Corsicana da olio. We evaluated several parameters in olive fruits (dry matter, oil content, total soluble solids, total polyphenol and antioxidant activity) and oils (legal indices, total chlorophylls and tocopherols, single polyphenols and volatile compounds, antioxidant activity). The results obtained in olive fruits showed that all the parameters changed significantly during ripening and seem to confirm that the best harvesting time is that selected by the growers, that is when 70% of olives has just turned dark-colored and the rest is green. Results on oil evidenced that all the samples fulfilled the requirements of the European community for extra-virgin olive oils and showed a decrease in total chlorophylls and tocopherols, simple phenols and antioxidant activity during ripening, except for Sivigliana da olio oils, which evidenced an increase in simple polyphenols at the last sampling. A total of 17 volatile compounds were found on oils and those responsible for the green notes of the oils increased during ripening. PCA analysis well distinguished Sivigliana da olio olives from the other two cultivars and, in general, the genetic factor better explained variability, with respect to the ripening degree.

Integrated Study of Qualitative Olive and Oil Production from Three Important Varieties Grown in Calabria (Southern Italy)

“…The obtained results denoted that all the olive oil productions of October were classified as extra virgin according the official regulations. The total free acidity value of olive oils tended to increase during the harvesting time, due to the enhancement of lipase activity, in agreement with what was reported by Conte et al . The limit for extra virgin olive oil (0.8%) was exceeded in Ottobratica and Grossa di Gerace oils: the first ones, in particular, showed variations of the mean values from 0.31 to 0.88%, but some samples produced in November in both crop years were below the legal value.…”

Bioactive compounds and quality evaluation of ‘Wonderful’ pomegranate fruit and juice as affected by deficit irrigation

“…The physical attributes mentioned above differ depending on the cultivar, growing region, maturity, climate, age of trees, fruit maturity, storage circumstance, and agronomic practices, among which irrigation is crucial. 16 Different authors have reported that regular drip irrigation throughout the season had a positive effect on fruit yield and fruit weight. 16,17 Different studies have also been conducted on pomegranate tree performance under deficit irrigation (DI), which involved reducing the amount of water provided to the crop during the growing season to a level below that needed for maximum plant growth.…”

“…16 Different authors have reported that regular drip irrigation throughout the season had a positive effect on fruit yield and fruit weight. 16,17 Different studies have also been conducted on pomegranate tree performance under deficit irrigation (DI), which involved reducing the amount of water provided to the crop during the growing season to a level below that needed for maximum plant growth. The results of these studies, especially those regarding fruit quality characteristics, are contradictory.…”

Conservation of Native Wild Ivory-White Olives from the MEDES Islands Natural Reserve to Maintain Virgin Olive Oil Diversity

“…Indeed, even the Marfil variety of ivory olives has larger fruits (2.2 g) with a higher fat content (40% db) [ 15 ]. Though fruit size and fat content can change along the ripening process [ 32 ], the very low values observed, at a relative high ripe index, makes unexpectable to reach those values typical for traditional cultivated varieties. This means that possibly we are facing a real wild olive population.…”