Densimetric sorting of olives to control olive oil quality

Abstract

Extra virgin is the most valuable commercial category among olive oils, and its quality is influenced by various factors, among which the olive fruit plays a fundamental role. The olives that enter the mill exhibit significant variability in physical and chemical characteristics, potentially impacting the quality of the extracted oil. Therefore, selecting the olives in post-harvest could be a crucial step, especially for differentiating the final product and producing high-quality oil. This work aimed to conduct post-harvest densimetric sorting of the olives. For this purpose, a saline solution was used with different concentrations of salt over the 3 days of harvesting, which made it possible to divide the initial olive batch into two sub-batches with different densities. The respective oil was extracted from each sub-batch, called low- and high-density oils, respectively, and then appropriate physical–chemical analyses were performed to characterize both the olives and the oils. Although both oils were classified as extra virgin, significant differences were observed, with higher concentrations of phenolic and volatile compounds associated with positive sensory attributes in the low-density oils. Densimetric sorting of olives could represent a novel approach in the field of extra virgin olive oil production, enabling potential differentiation of the final product.

Practical Applications: The results obtained in the study could be applied at an industrial level to classify olives in the post-harvest phase. This could allow to produce extra virgin olive oils (EVOOs) with different chemical and sensory characteristics, particularly in terms of volatile and phenolic compounds. This would make it possible to diversify the production of EVOO, satisfy the diverse needs of consumers, allow producers to be more competitive in the market, and, in general, improve the overall quality of the final product.