`‘Zapping’ May Make Olive Oil Extraction Faster, Cheaper - Olive Oil Times
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‘Zapping’ May Make Olive Oil Extraction Faster, Cheaper

By Julie Butler
Apr. 11, 2012 10:38 UTC


Photo: FDA

‘Zapping’ olive paste via a non-ther­mal tech­nol­ogy called pulsed elec­tric fields (PEF) shows promise in improv­ing vir­gin olive oil yield while reduc­ing energy use and pre­serv­ing qual­ity, two European projects sug­gest.

PEF is already used in food pro­cess­ing for ster­il­iza­tion and preser­va­tion and has been shown to increase yields in the extrac­tion of other juices, such as from oranges. Now research reveals its poten­tial for mak­ing olive oil.

According to European Commission research por­tal CORDIS, the poten­tial spin-offs from one recent EC-spon­sored PEF project include reduc­tion in olive paste tem­per­a­ture dur­ing pro­cess­ing, pro­vid­ing energy and time sav­ings — com­pared to ther­mal or enzyme treat­ment — and improv­ing oil qual­ity while retain­ing yield. PEF also has poten­tial to increase the oil’s phy­tonu­tri­ent con­tent, ​“to improve con­sumer health ben­e­fits and olive oil shelf life,” CORDIS reports.

And last month in ​“Food and Bioprocess Technology”, sci­en­tists from Spain’s University of Zaragoza reported that their own stud­ies had found that PEF allowed the use of lower tem­per­a­tures dur­ing malax­a­tion, the extrac­tion stage where the oil droplets agglom­er­ate.

This is impor­tant because higher tem­per­a­tures increase oil yield but harm qual­ity, and European Union reg­u­la­tions say that to use the term ​“first cold press­ing” or ​“cold extrac­tion”, the oil must be obtained at a tem­per­a­ture below 27°C (80 °F).

In their arti­cle, Effects of Pulsed Electric Field on Yield Extraction and Quality of Olive Oil, the researchers said they tested dif­fer­ent inten­si­ties (0 – 2 kV/cm) of PEF on Arbequina olive paste with dif­fer­ent malax­a­tion times (0, 15, and 30 min) and tem­per­a­tures (15 and 26°C).

They explained PEF as the appli­ca­tion of direct cur­rent, high-volt­age pulses, in short burts rang­ing between micro- and mil­lisec­onds.

In their tests, extrac­tion yield improved 54 per­cent when the olive paste was treated with PEF (2 kV/cm) with­out malax­a­tion.

When com­bined with malax­a­tion at 26°C, PEF treat­ment did not increase the extrac­tion yield com­pared with a con­trol. But at 15°C, PEF of 2 kV/cm improved the extrac­tion yield by 14.1 per­cent — cor­re­spond­ing to 1.7kg more oil per 100kg of olives.

Parameters such as for acid­ity, per­ox­ide, K232 and K270 were not affected by PEF and a sen­sory analy­sis found no bad fla­vor or taste in the oil.

“The appli­ca­tion of a PEF treat­ment could per­mit reduc­tion of the malax­a­tion tem­per­a­ture from 26 to 15°C with­out impair­ing the extrac­tion yield,” the researchers said.


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