Pulsed Electric Fields for the Treatment of Olive Pastes in the Oil Extraction Process

Abstract

The aim of this study was to evaluate the ability of pulsed electric field (PEF) technology to improve the extractability and enhance the oil quality in an industrial olive oil extraction process. Using a PEF device on olive pastes significantly increased the extractability from 79.5% for the control, up to 85.5%. The PEF system did not modify the primary legal quality parameters or total concentrations of phenols, aldehydes, and esters. On the contrary, the non-thermal treatment slightly enhanced the dialdehydic forms of decarboxymethyl elenolic acid linked to hydroxytyrosol (3,4-DHPEA-EDA) and tyrosol (p-HPEA-EDA), and decreased the total saturated and unsaturated C5 and C6 alcohols of the PEF EVOO (Extra Virgin Olive Oil) compared to the control test. This study confirmed that PEF technology can improve olive oil extraction and quality.

The ultrasound application does not affect to the thermal properties and chemical composition of virgin olive oils

“…Recently, emerging technologies are being applied into the olive paste malaxation process [8] , [9] , such as ultrasound (US) waves [10] , [11] , [12] , [13] , [14] , [15] , [16] , [17] , [18] , [19] , [20] , [21] , [22] , [23] , microwave [24] , [25] , [26] , pulsed electric field [27] , [28] , [29] , [30] , [31] among others [2] , [22] , [32] , [33] . These technologies are being used with the aim to establish an alternative system to the traditional malaxation that allows reducing time and improving the process efficiency [6] , [8] , [9] , [11] .…”

Partial De‐Stoning of Olive Paste to Increase Olive Oil Quality, Yield, and Sustainability of the Olive Oil Extraction Process

“…In order to improve the logic of the process and to optimize the use of the machines for each single phase of the extraction process, in the last few years a new olives de-stoner machine has been developed. [24][25][26][27][28] It is characterized by an innovative system to separate the specific fraction of stone (from 0% to 100% of olive stone fragments) leaving. Thus, it is possible to remove a variable amount of pits from the paste while the remaining amount is retained in the paste to be sent to the next malaxation operation.…”

Impact of Emerging Technologies on Virgin Olive Oil Processing, Consumer Acceptance, and the Valorization of Olive Mill Wastes

“…Electroporation, induced by the PEF treatment, exposes the cell membrane to an electric field, resulting in an increase in the transmembrane potential (accumulation of oppositely charged ions on both sides of the nonconductive cytoplasmic membrane) and the formation of pores in weak areas of the membrane [ 25 , 55 ]. The electroporation leads to leakage of intracellular compounds and increases mass transfer, as shown in Figure 1 .…”

“…Accordingly, in addition to improving the oil extraction yield, a PEF treatment (2 kV cm −1 and frequency of 25 Hz) applied to Arroniz olive paste enhanced the EVOO quality in terms of polyphenol, phytosterol, and tocopherol contents [ 24 ]. A positive effect on extractability was also observed when olive paste from the Nocellara del Belice cultivar was treated with PEF (2 kV cm −1 , 7.83 kJ/kg), leading to a 40.5% reduction in pomace oil loss without affecting the oil quality and causing a slight increase in the amount of oleacein and oleocanthal [ 25 ]. From the health point of view, high contents of secoiridoids are of interest due to their anti-inflammatory activity, which can be significant in many pathologies.…”