New generation decanters allow operators to make real-time adjustments during the virgin olive oil extraction process in order to gain the best performance possible. However, the opportunity to act in line requires a deep understanding of the consequences of changing machine parameters. To this purpose, an experiment was carried out at industrial scale. The decanter feed rate (Fr), ranging from 4075 to 5820 kg h−1, the bowl/screw conveyor differential speed (∆n), set at 18 and 22, and two ripening degrees of the olives were considered as process variables. Two combinations Fr-∆n, namely 4620 kg h−1 at ∆n-18 and 5210 kg h−1 at ∆n-22, were found to similarly maximize the process efficiency, regardless the raw material features. After pointing out the best working settings, the corresponding virgin olive oils were compared. The analysis of variance showed that peroxide value, K232, K270, phenols, chlorophylls, β-tocopherol, fruity and bitter notes, and C6 volatile compounds were significantly affected by the machine parameters. An inverse proportionality was observed between the combination Fr-∆n and the phenolic compounds. On the whole, the sampling factor exerted a larger influence on the product quality than the decanter set-up.
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