Higher Yield and Polyphenol Content in Olive Pomace Extracts Using 2-Methyloxolane as Bio-Based Solvent

Abstract

Despite its severe toxicity and negative environmental impact, hexane remain the solvent of choice for the extraction of vegetable oils. This is in contrast with the constantly growing demand for sustainable and green extraction processes. In recent years a variety of alternatives to hexane have been reported, among them 2-methyloxolane (2-MeOx), which has emerged as a promising bio-based alternative. This study evaluates the possibility of replacing hexane, in the extraction of olive pomace (OP), with 2-MeOx, both dry and saturated with water (4.5%), the latter of which is called 2-MeOx 95.5%. The three solvents have been compared in terms of extraction yield and quality, as well as the lipid and polyphenol profiles of the extracts. The work concluded that both dry 2-MeOx and 2-MeOx 95.5% can replace hexane in OP extraction, resulting in higher yields and extracts richer in phenolic compounds. This study should open the road to further semi-industrial scale investigations toward more sustainable production processes.

Semi-industrial Countercurrent Extraction of Soybean with 2-Methyloxolane for High-Quality Protein and Oil

“…Several studies have reported that 2-MeOx is also an efficient solvent for the extraction of phenolic compounds and yields polyphenol-rich extracts 41 with high antioxidant activity. 25,36,42 In this study, the oil obtained with 2-MeOx contained a significantly higher concentration (p < 0.05) of polyphenols than the oil obtained with hexane. The higher content of UM and phenolic compounds was probably the reason for the longer oxidative stability (induction time >70 h) compared to the hexane-extracted oil.…”

“…Increasing the water content and thus the a w of the solvent favors the transfer of water from the solvent to the matrix, and the more hydrated wet meal retains more solvent, which increases the SRIs. Furthermore, this phenomenon causes swelling of the matrix, 36 which has a significant effect on the extraction kinetics. 25 These results provide a better understanding of the extraction process in its entirety and can be used to modulate water transfer between the matrix and the miscella.…”

“…This is consistent with previous studies that showed higher extraction yields with 2-MeOx. 25,36,39 A general rule is that the peroxide value (PV) should not exceed 10−20 mequiv/kg fat to avoid a rancid taste. 40 The PV of the crude oil extracted with hexane was below this limit, with the oil extracted with 2-MeOx having a higher PV.…”

Leading Edge Technologies and Perspectives in Industrial Oilseed Extraction

“…The 2-MeOx/H 2 O mixture (95.5/4.5% at 55 °C) must be fed to another distillation step to recover the dry 2-MeOx. However, studies have shown that 2-MeOx 95.5% can be used directly for oil extraction, showing a similar efficiency to the dry solvent [ 77 , 78 ]. Using COSMO-RS and Hansen solubility predictions, Sicaire et al [ 66 ] showed that 2-MeOx can be considered the best alternative to n -hexane among all solvents tested, as it can efficiently dissolve the desired compounds.…”

Role of Olive Bioactive Compounds in Respiratory Diseases

“…Hence, EVOO has the highest polyphenol content compared to refined olive oils, which is about 500 mg/L [ 43 , 44 ]. A remarkably high concentration of polyphenols and flavonoids was also reported in olive by-products, i.e., paste, pomace and aqueous extract [ 42 , 45 , 46 ]. Therefore, due to minimal processing, EVOO had higher levels of polyphenols and was more readily absorbed than refined olive oil [ 47 ].…”