Biomolecules extraction from coffee and cocoa by‐ and co‐products using deep eutectic solvents

Abstract

BACKGROUND: Coffee pulp (CP), cocoa husk (CH), and pod husk (CPH) are the main agro-residues from coffee and cocoa industries. They are sources of useful biomolecules, such as phenolic compounds, fibers, and alkaloids, among others. In this study, different compositions of deep eutectic solvents (DES) were investigated as a green and sustainable extraction media, with respect to their extraction capacity. The extraction yields were evaluated using heat stirring-assisted extraction (HSE) or ultrasound-probe assisted extraction (UPAE). RESULTS: The results showed an important effect of the DES composition. Choline chloride (ChCl) based-DES were the most effective, specifically lactic acid:ChCl (2:1 mol ratio), and the extraction capacity of DES was higher with UPAE (3 min/constant duty cycle (200 W)), in comparison with HSE (1 h/30 min). Chlorogenic acid, caffeine, and theobromine were identified as the main bioactive compounds. Interestingly, under specific conditions, DES allowed the formation of a molecule, identified as furfural by ultrahigh-performance liquid chromatography mass spectrometry (UPLC-MS), which could not be obtained using conventional extraction solvent (ethanol 70% v/v).CONCLUSION: DES showed a sustainability and high extraction capacity of biomolecules. In addition, their use as extraction solvents could lead to the formation and production of valuable building block molecules from plant biomass.

Innovative Extraction Techniques Using Deep Eutectic Solvents and Analytical Methods for the Isolation and Characterization of Natural Bioactive Compounds from Plant Material

“…In the case of extraction of phenolic acids by the UAE-DES/NADES methods, most authors have found choline chloride:lactic acid-based DES (molar ratio usually 1:2) as the most promising solvent [103][104][105]. The combination of choline chloride with other organic acids such as: p-toluenesulfonic acid [66], oxalic acid [106] and citric acid [107] is also interesting.…”

“… Sugar-based NADES have the highest viscosity, which makes them difficult to handle and consequently limits their use in the commercial extraction processes [ 82 ]. Choline chloride:organic acid-based DES/NADES in combination with UAE is the most effective extraction methodology described for the isolation of phenolic acids from the various plant matrices [ 66 , 105 , 106 , 107 , 126 ]. In the case of the flavonoid class, the results presented in the majority of the papers have identified choline chloride:polyalchol-based DES/NADES as the most promising solvents ( Table 1 and Table 2 ).…”

“…Choline chloride:organic acid-based DES/NADES in combination with UAE is the most effective extraction methodology described for the isolation of phenolic acids from the various plant matrices [ 66 , 105 , 106 , 107 , 126 ].…”

Recovery of Chlorogenic Acids from Agri-Food Wastes: Updates on Green Extraction Techniques

“…NaDES are stable eutectic mixtures composed of a hydrogen bond acceptor (HBA) and a hydrogen bond donor (HBD). Recently, Ruesgas-Ramón et al [ 62 ] tested six different DES using heat-stirring assisted extraction (1 h, 60 °C) to extract CGAs from coffee and cocoa by-products. The extraction yield was compared with the results obtained in the same experimental conditions using 70% ethanol.…”

Use of Deep Eutectic Solvents in the Treatment of Agro-Industrial Lignocellulosic Wastes for Bioactive Compounds

“…Major flavonoids were identified as quercetin, kaempferol, and myricetin. Very recently, Ruesgas-Ramón et al [105] used agro-residues from coffee and cocoa industries to recover biomolecules using DESs. The authors reported that the use of lactic acid-ChCl (2:1) provided higher phenolics extraction with ultrasound-probe-assisted extraction than heat stirring-assisted extraction.…”