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

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Journal of The Science of Food and Agriculture
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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. © 2019 Society of Chemical Industry
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81
Research Article
Received: 20 May 2019 Revised: 11 August 2019 Accepted article published: 22 August 2019 Published online in Wiley Online Library: 6 November 2019
(wileyonlinelibrary.com) DOI 10.1002/jsfa.9996
Biomolecules extraction from coffee and cocoa
by- and co-products using deep
eutectic solvents
Mariana Ruesgas-Ramón,aMirna L Suárez-Quiroz,bOscar González-Ríos,b
Bruno Baréa,c,d Guillaume Cazals,eMaria C Figueroa-Espinozaa* and
Erwann Durandc,d*
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.
© 2019 Society of Chemical Industry
Supporting information may be found in the online version of this article.
Keywords: coffee pulp; cocoa husk; cocoa pod husk; DES (deep eutectic solvents); phenolic compounds; furfural
INTRODUCTION
Coffee and cocoa are important commodities widely distributed
and consumed around the world. Indeed, in 2017/2018 sea-
son, the world production of green coffee and cocoa beans
reached 10.5 and 4.6 million tons, respectively.1,2 However, coffee
and cocoa transformation industries generate large amounts of co-
and by-products.
Coffee pulp (CP) is the main by-product generated after mechan-
ical pressing of the coffee fruit (cerise) in water through a pulper.
CP represents around 40% of the fresh weight of coffee fruits.3
Regarding the cocoa manufacturing, the process starts with the
harvest and then opening of the fruit to remove beans from the
cocoa pod husk (CPH). CPH is the principal generated by-product,
usually left on the harvest fields where approximately ten tons
are generated to produce one dried cocoa bean.4Cocoa beans
are then fermented, roasted, and separated from cocoa husk (CH),
which is the outer portion of the cocoa beans encasing the nibs.
CH is the principal co-product from the cocoa processing and rep-
resents 12% of the dry bean.5
CP has been used for animal feed, organic fertilization, and
ethanol (EtOH) production;6while CPH and CH have been
employed as sources of organic matters (compost) or nutrients
to the soil, or more rarely for its pectin extraction.5,7 How-
ever, the use of CP, CH, and CPH as economic and sustainable
sources for high-added value biomolecules could provide an
Correspondence to: Dr E Durand or MC Figueroa-Espinoza,CIRAD/UMR IATE, TA
B-62 / 16, Maison de la Technologie/ Bât 16, 73 rue Jean-François Breton, 34398
MONTPELLIER Cedex 05, France. E-mail: erwann.durand@cirad.fr (Durand);
maria.figueroa@supagro.fr (Figueroa-Espinoza)
aIATE, Montpellier SupAgro,Montpellier, France
bTecnológico Nacional de México/Instituto Tecnológico de Veracruz, UNIDA,
Veracruz, Mexico
cCIRAD, UMR IATE,Montpellier, France
dIATE, University of Montpellier, CIRAD, INRA, Montpellier SupAgro, Montpellier,
France
eLaboratoire de Mesures Physiques, Service Commun de l’Université´
c
Montpellier 2, Plateau Techniquede l’Institut des Biomolécules Max Mousseron,
Montpellier, France
J Sci Food Agric 2020; 100: 81–91 www.soci.org © 2019 Society of Chemical Industry
... The application of choline-chloride-based DESs for the extraction of coffee and cocoa waste matrices was also carried out by Ruesgas-Ramόn et al. [122]. In this case, the combination of ChCl and lactic acid (2:1 molar ratio) with 10% water was found to be the best choice in terms of the total phenol content detected in cocoa husks (obtaining 52.86 ± 0.78 g GAE/100 g according to the Folin-Ciocalteu method and 0.62 ± 0.08 gGAE/100 g with HPLC) [122]. ...
... The application of choline-chloride-based DESs for the extraction of coffee and cocoa waste matrices was also carried out by Ruesgas-Ramόn et al. [122]. In this case, the combination of ChCl and lactic acid (2:1 molar ratio) with 10% water was found to be the best choice in terms of the total phenol content detected in cocoa husks (obtaining 52.86 ± 0.78 g GAE/100 g according to the Folin-Ciocalteu method and 0.62 ± 0.08 gGAE/100 g with HPLC) [122]. Interestingly, the extraction yields, when still using the same DES as the solvent, increased when the process was coupled with ultrasound-probe-assisted extraction (3 min/constant duty cycle, 200 W, at 72 °C), even compared to heat-stirring-assisted extraction (HSE) (60 °C for 1 h) [122]. ...
... In this case, the combination of ChCl and lactic acid (2:1 molar ratio) with 10% water was found to be the best choice in terms of the total phenol content detected in cocoa husks (obtaining 52.86 ± 0.78 g GAE/100 g according to the Folin-Ciocalteu method and 0.62 ± 0.08 gGAE/100 g with HPLC) [122]. Interestingly, the extraction yields, when still using the same DES as the solvent, increased when the process was coupled with ultrasound-probe-assisted extraction (3 min/constant duty cycle, 200 W, at 72 °C), even compared to heat-stirring-assisted extraction (HSE) (60 °C for 1 h) [122]. The main bioactive compounds identified in the extracts were theobromine, caffeine and chlorogenic acid [122]. ...
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