2-Methyloxolane as a Bio-Based Solvent for Green Extraction of Aromas from Hops (Humulus lupulus L.)

Abstract

The potential of using the bio-based solvent 2-methyloxolane, also known as 2-methyltetrahydrofuran or 2-MeTHF, as an alternative to petroleum solvents such as hexane, was investigated for the extraction of volatile compounds from hop cones (Humulus lupulus L.). Lab scale extractions were coupled with in silico prediction of solutes solubility to assess the technical potential of this bio-based solvent. The predictive approach was performed using the simulation software COSMO-RS (conductor like screening model for real solvants) and showed that the 2-methyloxolane is as good as or better than hexane to solubilize the majority of aromas from hop cones. The experimental results indicated that the highest aroma yield was obtained with 2-methyloxolane with 20.2% while n-hexane was only able to extract 17.9%. The characterization of aromas extracted by the two solvents showed a similar composition, where lupulone was the main component followed by humulone. No selectivity of the solvents was observed for any of the major analytes. Finally, a sensory analysis was performed on the extracts, showing that both concretes using 2-methyloxolane and hexane have similar olfactory profiles. The results indicate that 2-methyloxolane could be a promising bio-based extraction solvent for hexane substitution.

Dry and Aqueous 2-Methyloxolane as Green Solvents for Simultaneous Production of Soybean Oil and Defatted Meal

“…Predicted solubilities of some selected solutes usually found in soybean oil were determined in 2-MeOx, 2-MeOx 95.5%, and n -hexane, using the conductor-like screening model for real solvents (COSMO-RS). Briefly, COSMO-RS is a calculation method developed by Klamt using a quantum chemistry model, which has been applied since 2000 for solubility prediction in the context of natural products extraction. , More detailed explanations are presented in our previous studies. , Calculations were performed using the COSMOThermX software (Version 18.0.2, COSMOlogic GmbH & Co., Leverkusen, Germany), at 55 °C, using the “iterative” mode, considering that solutes and solvents are pure and in a liquid state.…”

Alternative and sustainable solvents for green analytical chemistry

“…At optimum conditions, it was found that 2-MeOx outperformed hexane by increasing limonene extraction yield by 40%. The following year, its ability to extract volatile compounds from hop cones was also demonstrated[21]. This time again the aroma yield obtained with 2-MeOx (20.2%) was higher than what was obtained with n-hexane (17.9%) and both extracts had similar compositions and olfactory profiles.2-MeOx appears to be an efficient bio-based solution for preparation of color samples as well, particularly in the case of carotenoids.…”

2-Methyloxolane (2-MeOx) as Sustainable Lipophilic Solvent to Substitute Hexane for Green Extraction of Natural Products. Properties, Applications, and Perspectives

“…Hexane is typically one of the main solvents used to recover aromatic compounds from natural products. Considering its hazardous characteristic to human health and environment, a lot of efforts are made to find a suitable alternative applicable in the industry [ 30 , 31 , 39 , 40 ].…”

“…The results of this analysis support the suitability of replacing hexane with 2-MeOx to develop sustainable processes. Recently, we investigated the potential of using 2-MeOx for the extraction of volatile compounds from hop cones [ 40 ]. Again, the crude yields provided by 2-MeOx either after maceration or Soxhlet procedure were higher than that of hexane (16.6 and 20.2% against 12.7 and 17.9%).…”