Flash Thermal Conditioning of Olive Pastes during the Oil Mechanical Extraction Process: Cultivar Impact on the Phenolic and Volatile Composition of Virgin Olive Oil

Abstract

The concentration of phenolic and volatile compounds in virgin olive oil (VOO) is closely related to the different operative conditions applied to the mechanical extraction process of the olive oil. However, the great qualitative and quantitative variability of these compounds indicates an important role played by genetic and agronomic aspects. A heat exchanger was placed in front of a traditional, covered malaxer to study the impact of flash thermal conditioning (FTC) of olive paste on the quality of VOO, which is highly influenced by phenolic release and aroma generation. The VOO flash thermal conditioning of five major Italian cultivars showed a higher concentration of phenols (range of increase percentage, 9.9-37.3%) compared to the control trials, whereas the FTC treatment featured a differentiated impact on the volatile fractions, associated with the genetic origins of the olives.

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

“…The evaluation of the volatile molecules present in the headspace (HS) of EVOO samples was performed with a solid-space microextraction (SPME) using a 50/30 µm divinylbenzene/Carboxen/poly(dimethylsiloxane) (DVB/CAR/PDMS) 1-cm-long fiber (Stableflex; Supelco, Inc., Bellefonte, PA, USA) and controlled using a Varian CP 8410 autoinjector (Varian, Walnut Creek, CA, USA). The gas chromatography-mass spectrometry analyses (GC-MS) were performed using a Varian 4000 GC-MS equipped with a 1079 split/splitless injector with a fused-silica capillary column (DB-Wax-ETR, 50 m, 0.32-mm i.d., 1 µm film thickness; J&W Scientific, Folsom, CA, USA) using the method described in Veneziani et al [36], and the data of the main C5 and C6 saturated and unsaturated aldehydes and alcohols and of esters were expressed as micrograms of volatile compound per kilogram of oil.…”

Olive Oil Processing: Current Knowledge, Literature Gaps, and Future Perspectives

“…Recent studies proposed the modification of malaxation equipment and the pretreatment or post‐treatment of the paste to improve process efficiency (Abenoza et al, ; Bejaoui et al, , ; Clodoveo, ; Clodoveo et al, ; Esposto et al, ; Fiori et al, ; Iqdiam et al, ; Leone et al, , , ; Puértolas and Martínez De Marañón, ; Sari and Ekinci, ; Tamborrino et al, ; Taticchi et al, ; Veneziani et al, , ). An approach to reduce the duration or temperature of malaxation is paste preheating using microwave (MW) treatment or high‐power ultrasound or pulsed electric field (PEF) or flash thermal treatment application or megasonic treatment (Abenoza et al, ; Clodoveo and Hachicha Hbaieb, ; Leone et al, ).…”

“…Table presents an overview of the research results on the examination of premalaxation or postmalaxation treatment of the olive paste on the olive oil quality. One of the simplest pretreatment approaches is to heat (to decrease the malaxation time) or cool (to decrease the rate of chemical and enzymatic reactions) the paste prior to malaxation using tubular heat exchangers (Esposto et al, ; Fiori et al, ; Leone et al, ; Veneziani et al, , ).…”

“…Regarding the preheating of the paste approach, different preheating and malaxation time–temperatures were examined (Esposto et al, ; Fiori et al, ; Leone et al, ; Veneziani et al, ). Nevertheless, only two studies report the effect of preheating on extraction yield.…”

“…On the other hand, Leone et al () achieved a reduction of the malaxation time of 10 min by preheating. The effect of preheating on the quality characteristics of the oil was different for the different studies (Table ) possibly depending on the time–temperature profile applied on the paste in each study and trial (Esposto et al, ; Fiori et al, ; Leone et al, ; Veneziani et al, ). In addition, a strong effect of cultivar was observed on the effect of heating on volatiles (Veneziani et al, ).…”