Author's personal copy
Journal of Food Engineering 92 (2009) 112–118Contents lists available at ScienceDirect
Journal of Food Engineering
journal homepage: www.elsevier.com/locate/jfoodeng
Improved extraction of virgin olive oil using calcium carbonate as coadjuvant extractant
Francisco Espínola, Manuel Moya, Diego G. Fernández, Eulogio Castro *
Departamento de Ingeniería Química, Ambiental y de los Materiales, Universidad de Jaén, Campus Las Lagunillas, Edif.B-3, 23071 Jaén, Spain
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Olive oil is gaining a growing interest because of its beneﬁcial effects on human health and hence olive oil production is spreading worldwide. As a result, technical improvements in the olive oil extraction process are continuously under study. In this sense, this work deals with the effect of micronized calcium carbonate, anew technological coadjuvant, on the physical extraction of virgin olive oil. The assays were performed with three olive (Olea europaea L.) varieties, Picual, Hojiblanca and Arbequina, according to different experimental designs. The results were compared with those obtained using micronized talc, a coadjuvant authorized by European Union regulations. The use as a technological coadjuvant ofcalcium carbonate, E170 food additive, produced an increase of olive oil extraction yield up to 24% when the mixing temperature was maintained at 30 °C for 55 min. Moreover, micronized carbonate allows a lower temperature to be used without extraction decrease, resulting in higher quality olive oil. Concerning analytical determinations of oils, no signiﬁcant differences were found when comparing oilsobtained with or without carbonate and all of them could be classiﬁed as ‘‘extra virgin olive oil” according to European norms. Finally, in comparison to talc use, no statistical differences were found in terms of extraction yields. Ó 2008 Elsevier Ltd. All rights reserved.
Article history: Received 16 May 2008 Received in revised form 24 October 2008 Accepted 27 October 2008 Available online14 November 2008 Keywords: Olea europaea Coadjuvant Calcium carbonate Talc Physical extraction Extra virgin olive oil Oil quality Oil yield
1. Introduction Olive oil has been claimed to be a healthy food whose consumption is associated, for example, to a low mortality by cardiovascular disease (Covas, 2007). Olive tree cultivation, traditionally established in the Mediterranean countries, hasbeen extended to many other parts in the world. As a result of new plantations and improvements in culture techniques, the production of olive oil has increased by 50% in the last ten years according to the International Olive Oil Council (2008). Among the different types of olive oils that may be produced, virgin olive oil is the most valuable one, as the extraction process preserves itsbeneﬁcial features. The industrial process for obtaining virgin olive oil includes just physical operations (Regulation EEC 1513/2001). The process begins by crushing the olive, the objective is to tear the ﬂesh cells to let the oil run out. Then olive paste has to be mixed; in this stage the droplets of oil merge into larger drops until they form ‘‘pockets” (coalescence) that can be separated into a...