Research Article Centrifugation, Storage, and Filtration of Olive Oil in an Oil Mill: Effect on the Quality and Content of Minority Compounds Alfonso M. Vidal , Sonia Alcal ´ a , Antonia de Torres, Manuel Moya , and Francisco Esp´ ınola Centre for Advanced Studies in Energy and Environment (CEAEMA), Agrifood Campus of International Excellence (ceiA3), Dept. Chemical, Environmental and Materials Engineering, University of Ja´ en, Paraje Las Lagunillas, Edif. B-3, 23071 Ja´ en, Spain Correspondence should be addressed to Alfonso M. Vidal; amvidal@ujaen.es Received 17 August 2018; Accepted 23 January 2019; Published 18 February 2019 Guest Editor: Nabil Ben Youssef Copyright © 2019 Alfonso M. Vidal et al. is is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Centrifugation, storage, and filtration of olive oil were evaluated in an oil mill to determine their effect on the final quality of virgin olive oil. e main functions of these processes are to clarify the olive oil by removing water, solids, and other possible suspended particles. Although some changes were detected in the oil quality parameters after these processes, all the samples were extra virgin olive oil. e phenolic and volatile compound content of the olive oil was influenced by vertical centrifugation processing. Significantly, vertical centrifugation led to a 53% reduction in ethanol content. Oil storage before filtration resulted in a significant increase of around 30% in the peroxide index, while the antioxidant capacity decreased by 78%. Comparison of the results for filtered and unfiltered oil samples revealed that the most significant change was the reduction in the photosynthetic pigment content, with a decrease of around 50% in chlorophyll. Due of all this, the conditions applied in vertical centrifugation and the time of storage of the olive oils should be further controlled, enabling cleaning and decantation but avoiding the reduction of the antioxidant capacity and the content of phenolics compounds. 1. Introduction Virgin olive oil (VOO) is a fat known worldwide for its beneficial properties for human health. e consumption of olive oil in the Mediterranean diet is associated with low mortality from cardiovascular disease [1]. Several health benefits have been associated with certain antioxidant compounds such as phenols [2]. e health claims on “olive oil polyphenols” by the EEC [3] refer to the impact of bioactive phenolic compounds on the protection of blood lipids against oxidative stress [4]. High nutritional quality arises from large amounts of unsaturated fatty acids in the composition of oil, such as oleic acid and linolenic acid. e production of VOO is solely carried out by physical and mechanical extraction processes. Oil washing is a step of the process, which is performed in a vertical centrifuge (VC). After obtaining the oil, it is filtered to eliminate any solids in the suspension. Washing represents an important source of oxidative reactions arising from the contact between water and oil [5]. e distribution of phenolic compounds in the water and oil phases depends on their solubility in the phases [6]; phenolic compounds may thus be found in the wastewater and pomace. Vertical centrifugation has a great effectiveness in clarifying the oil, although this process reduces the con- centration of minor compounds in the extra virgin olive oil (EVOO) [7]. e maximum oxygenation levels have been detected after VC treatment. e oxidation of olive oil during its shelf-life is negatively affected by the concen- tration of dissolved oxygen [8]. Inert gases have been used for oil oxygenation pre- vention and found to significantly extend the oil shelf-life [9]. Other researchers have focused on the effect of the water employed in the VC and on the content of alkyl esters in olive oils [10], where the content of ethyl and methyl esters were found to decrease with the use of water in the VC. Hindawi Journal of Food Quality Volume 2019, Article ID 7381761, 7 pages https://doi.org/10.1155/2019/7381761