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The aim of this work was both the monitoring of selected indices, directly connected to biochemical phenomena of olive oil fruit ripening, and the processing of experimental results to choose the most appropriate harvesting time for olives. Two different olive cultivars (Frantoio and Moraiolo) in two different olive orchards were studied, picking olives by hand once a week from the beginning of September to the beginning of December. Olive samples were analyzed for average weight, pulp/stone ratio, and Maturity Index. A homogeneous batch of olives was crushed, and the olive paste was used for the measurement of water, oil, sugar, and phenolic compounds contents in olive oil fruits. Formally similar kinetics of oil and sugar contents were obtained for both studied cultivars and orchards. Oil contents showed an increasing sigmoidal trend tending to an asymptote; sugar contents showed an opposite behavior with a decreasing sigmoidal trend tending to an asymptote. The total phenolic compounds content showed a decreasing trend during ripening. The secoiridoids oleuropein aglycon and oleuropein were among the most abundant phenolic compounds. Their contents showed a linear decrease during olive ripening, modelled by a significant pseudo‐zero order kinetics; trends were cultivar‐dependent, though similar for both orchards. Practical applications: Both monitoring and processing of chemical ripening indices in olive oil fruits may be useful to define an adequate ripening degree and to predict harvest time. Modeling of oil and sugar content kinetics during ripening may improve the prediction approach to harvesting time of olive oil fruits, as compared to the common Maturity Index method. For instance, the harvest target of maximizing processing yield may be attained on the basis of the following phenomenological evidence: A constant maximum value for oil content corresponds to attainment of a constant minimum value of sugar content. A sensible choice of the most appropriate harvesting time for olives may be made by performing a combined evaluation of kinetics for oil, sugar, and phenolic compounds contents. An example to understand how a change in harvesting time may affect olive composition and, potentially, the quality of oil to be extracted, was reported in this paper. An example of combined kinetic trends of the sugar (·····), oil (—), and oleuropein (‐‐‐‐) contents to choose the harvesting time of olive oil fruits for Frantoio cultivar on one of the orchards studied.

The aim of this work was to study, under different conditions, degradation of secoiridoids during extraction of extra virgin olive oil by following the effect of ascorbic and citric acid addition. Their effect was evaluated on oil obtained from both damaged olives and undamaged fresh olives. Addition of enzyme inhibitors to damaged olives during olive milling allowed us to obtain oil with a higher phenolic compound content. Conversely, addition of the same inhibitors to undamaged fresh olives, during oil milling, resulted in no significant improvement in the phenolic compound content of oil. A high presence of PPO was thus indirectly confirmed, as damaged olives were only found to be sensitive to action of inhibitors. Ascorbic acid was found to be more effective than citric acid in preserving phenolic compounds of oil. Trials on undamaged fresh olives confirmed occurrence of hydrolytic transformation phenomena for secoiridoids during extra virgin olive oil production process. In particular, the quantitatively most representative component for Frantoio cultivar was found to be 3,4‐DHPEA‐EDA. This compound may be considered a direct marker for the degree of transformation of secoiridoids during production process.Practical applications: The processing of undamaged olives resulted in the extraction of extra virgin olive oil with a higher phenol content. It could be indirectly inferred that a reduced activity of PPO caused a low secoiridoid degradation both before and after malaxation. Lightly scratched, overripe olives could be used in those markets where the addition of oxidation‐inhibiting substances is allowed. Using inhibitors can be suggested for olive washing step.

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