Pulsed Electric Field-Assisted Extraction of Aroma and Bioactive Compounds From Aromatic Plants and Food By-Products

Abstract

In this work, the effect of pulsed electric field (PEF) pre-treatment on the extractability in green solvents (i. e., ethanol–water mixture and propylene glycol) of target aroma and bioactive compounds, such as vanillin from vanilla pods, theobromine and caffeine from cocoa bean shells, linalool from vermouth mixture, and limonene from orange peels, was investigated. The effectiveness of PEF as a cell disintegration technique in a wide range of field strength (1–5 kV/cm) and energy input (1–40 kJ/kg) was confirmed using impedance measurements, and results were used to define the optimal PEF conditions for the pre-treatment of each plant tissue before the subsequent solid–liquid extraction process. The extracted compounds from untreated and PEF-treated samples were analyzed via GC-MS and HPLC-PDA analysis. Results revealed that the maximum cell disintegration index was detected for cocoa bean shells and vanilla pods (Zp = 0.82), followed by vermouth mixture (Zp = 0.77), and orange peels (Zp = 0.55). As a result, PEF pre-treatment significantly enhanced the extraction yield of the target compounds in both solvents, but especially in ethanolic extracts of vanillin (+14%), theobromine (+25%), caffeine (+34%), linalool (+114%), and limonene (+33%), as compared with untreated samples. Moreover, GC-MS and HPLC-PDA analyses revealed no evidence of degradation of individual compounds due to PEF application. The results obtained in this work suggest that the application of PEF treatment before solid–liquid extraction with green solvents could represent a sustainable approach for the recovery of clean labels and natural compounds from aromatic plants and food by-products.

Antioxidant and Anti-Inflammatory Effects of Extracts from Pulsed Electric Field-Treated Artichoke By-Products in Lipopolysaccharide-Stimulated Human THP-1 Macrophages

“…PEF treatments of artichoke stems were performed using a laboratory-scale batch system previously described [ 30 ]. Briefly, the apparatus consisted of a high-voltage pulsed power (25 kV–500 A) generator (Modulator PG, Scandi Nova, Uppsala, Sweden) capable of delivering monopolar square wave pulses (3–25 µs, 1–450 Hz) to the plant matrix placed between two plane parallel electrodes of stainless steel separated by a Teflon spacer (4 cm electrode gap, 75 cm 2 electrode area).…”

“…The high-performance liquid chromatography–photodiode array detection (HPLC–PDA) analysis for the identification of phenolic compounds in the extracts from both untreated and PEF-treated artichoke stems was performed using a Waters 1525 Separation Module coupled to a photodiode array detector, Waters 2996 (Waters Corporation, Milford, MA, USA), following a modified method reported by Carpentieri et al [ 30 ]. Analytical separation of the identified compounds was carried out in a Waters Spherisorb C18 reverse-phase column (5 μm ODS2, 4.6 × 250 mm, Waters Corporation, Milford, MA, USA).…”

“…During PEF treatment, plant biomass in wet form is placed between two electrodes of a treatment chamber and is exposed to an electrical treatment of moderate electric field intensity (0.5–10 kV/cm) and relatively low energy input (1–10 kJ/kg), which induces the permeabilization of cell membranes by pore formation, known as electroporation or electropermeabilization [ 27 ]. The PEF-assisted extraction process has shown great potential to selectively recover target intracellular compounds with high yield from a wide range of food-processing wastes and by-products [ 28 ], while reducing energy costs, solvent consumption and shortening treatment times [ 29 , 30 , 31 , 32 ].…”

Bioactive Compounds of Verbascum sinuatum L.: Health Benefits and Potential as New Ingredients for Industrial Applications

“…The drawback of this technology is the damage produced in the cell membrane when the following conditions are applied—between 500 and 1000 V/cm, for 10-4-10-2 s—due to a minor expansion in the temperature. However, PEF is a highly selective method with low energy cost, low time of extraction, and low quantity of solvent requirement [ 15 ]. Moreover, a study has shown that, in this technology, the plant cells are destroyed, allowing an increase in the extraction yield of bioactive compounds from plant tissues.…”

Impact of Non-Thermal Technologies on the Quality of Nuts: A Review

“…There are no data on nut aromas, although the positive effect of this treatment on the extraction of aroma in plants or the preservation of these aromas in food processing, fruits juices and vegetables has been demonstrated. These changes could be possible due to the fact that PEF induces cell permeabilization, facilitating enzyme-substrate reactions after the treatment [ 49 , 50 , 51 , 52 , 53 , 54 ].…”