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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 mole ratio), and the extraction capacity of DES was higher with UPAE (3 min/constant duty cycle (200 W)), in comparison with HSE (1h / 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 UPLC-MS, which could not be obtained using conventional extraction solvent (EtOH 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. This article is protected by copyright. All rights reserved.
... Moreover, such constituting compounds have been approved as food additives or supplements for human consumption because of their practically zero toxicity (Saini et al., 2022). Thereby, Ruesgas-Ramón et al. (2020) prepared six different DESs by using choline chloride, betaine, lactic acid, glycerol, and 1,4-butanediol to extract bioactive compounds from CP under heat-stirring assisted conditions for 1 h at 60 • C. Results exhibited the notable influence of extraction media composition on the recovery of phenolic compounds at both quantitative and qualitative levels. The mixture of choline chloride, lactic acid, and water (CCLA) at 1: 2: 1.5 mol ratio resulted the most efficient solvent for chlorogenic acid and caffeine recovery (4.1 and 3.9 mg/g CP, respectively) compared to the other tested DESs. ...
... The mixture of choline chloride, lactic acid, and water (CCLA) at 1: 2: 1.5 mol ratio resulted the most efficient solvent for chlorogenic acid and caffeine recovery (4.1 and 3.9 mg/g CP, respectively) compared to the other tested DESs. Moreover, similar total phenolic content was found for CCLA DES (9.6 mg GAE/g CP) and a 70% ethanolic extraction following the described HPLC-MS quantification methodology, although a notably decrease of chlorogenic acid (25.5%) and caffeine (33.9%) content was noticed for CCLA DES (Ruesgas-Ramón et al., 2020). In addition, high concentrations of DES aqueous solution, composed by diluted mixtures of choline chloride and glycerol, were observed to impair the extraction efficiency of caffeine from CP, which was attributed to the reduced mass transfer caused by the higher densities of the concentrated eutectic mixtures. ...
... However, as already pointed out by Ruesgas-Ramón and coworkers (2020), it is important to note the influence of the analytical methodology applied to the determined certain compounds in DES extracts e.g., total phenolic compounds by Folin-Ciocalteu methodology. Inconsistent results were found when comparing data from the latest colorimetric technique to those obtained by HPLC-MS quantification, which might be due to the analytical interferences exerted by the formation of insoluble salt precipitates induced by the choline chloride-based solvent (Ruesgas-Ramón et al., 2020). This limitation is one of the disadvantages recognized for DES (i.e., hindering analytics) however, other aspects must be considered such as the increased complexity of the reaction system, the large number combinations of HBA and HBD, the time-consuming relative to the recommended chemical characterization of the obtained DES prior carrying out the extraction process or the more arduous work to isolate the extracted compounds from the media when needed (Fig. 2). ...
Coffee pulp is an underutilized by-product of coffee industrial production rich in bioactive compounds such as phenolic compounds, caffeine, and dietary fiber. The widely known antioxidant, anti-inflammatory, anti-aging, antimicrobial and hepatoprotective health-promoting properties attributed to mentioned compounds enhance the use of coffee pulp as a bioactive food ingredient. Furthermore, the application of green sustainable extraction techniques pursuing highly efficient and selective extraction processes promotes this by-product exploitation in food science. Hence, this review gathers the available information relative to the impact of the extraction processes on the bioactive compound's recovery from coffee pulp, providing an overview of the most recent advances. An in-depth comparison workout between conventional and alternative extraction methods was performed to identify the most suitable techniques for coffee pulp valorization as functional ingredient until date. A critical discussion focused on advantages and drawbacks of the extraction methods applied to coffee pulp was included together a prospective of emerging extraction techniques.
... The use of NADES has been selected as the most convenient green method for coffee extraction, which is combined with other extraction methods i.e., ultrasonic, microwave, supercritical fluid to extract phenolics and caffeine . [45,46] Green extraction methods must maximize profits, while being safe, cheap, and robust. For decaffeination of coffee and for full utilization of polyphenols in nutraceuticals, an appropriate extraction method is required for caffeine and polyphenols as well as other secondary metabolites. ...
... [162] On the other hand, choline chloride-lactic acid at the molar ratio 1:2 showed highest extractability of CGA and caffeine from coffee pulp. [46] Asides, formation of a new compound also tentatively identified as furfural was noted upon extraction with this solvent, which could be due to the reaction between carbohydrates in the coffee pulp and acid in NADES. [43,161] NADES with organic acids and sugars were also studied for the extraction of coffee compounds. ...
... Nonconventional methods, such as SWE, UAE, MAE and NADES produced higher CGA and caffeine content in coffee extracts compared to conventional methods. [45,46] This is related to improved extraction effectiveness due to cell wall breakage and the release of CGA, and caffeine from the cells by non-conventional methods, and in accordance with previous results recorded on eggplants for CGA extraction from a different matrix . [165] The combination of extraction methods showed significantly (p < 0.05) higher CGA and caffeine levels compared to traditional methods, with an additional advantage of shorter extraction time. ...
Coffee is recognized worldwide as a top beverage owing to its several associated health benefits mediated by a complex mixture of unique bioactive substances. Chlorogenic acids are the key components of the phenolic fraction in green coffee seeds, accounting for up to 14% of the dry matter. The manufacturing of decaffeinated coffee demands efficient caffeine extraction from seeds and spent without solvent history effect for safety considerations. This has prompted researchers to investigate eco-friendly and cost-effective extraction technologies. Current extraction processes are not environmentally sustainable and have harmful consequences on humans. To date, developing a single standard method for effective extraction of certain complex compounds from coffee seeds remained a challenging procedure. The current review aims to give updated technical information regarding coffee plant green extraction methods, their advantages and disadvantages, and factors affecting efficacies for the recovery of bioactive compounds in coffee seeds and coffee spent. A comparative review of the uses of innovative green extraction techniques for coffee bioactive substances is introduced to present alternatives to conventional extraction methods. The most interesting finding was that the maximum total extractions of catechin (50.6 g/100 g) and caffeine (46.2 g/100 g) were achieved with enzymes in pressurized liquid extraction (PLE), and PLE-assisted with enzymes exhibited an enhancement in total phenolics and overall antioxidant compared to 50% hydro-ethanolic solutions. In addition, it has been claimed that the ultrasonic extraction can cut extraction time by 37% and temperature by 13%. These green extraction techniques represent favorable approaches to the exploitation of coffee chemicals as bioactives to explore their wide-reaching applications at an industrial level and for their valorization
... Mycorrhizal associations can overcome nutrient limitations to plant growth by increasing the availability of phosphorus. Fungi can release phosphorus into the soil solution from organic phosphates with the help of phosphatases, thereby providing access for plants to otherwise insoluble forms of phosphorus [105]. The greater availability of phosphorus to the mycorrhizal plant host is dependent on the ability of its symbiont to absorb and translocate inorganic phosphates to the host roots and to access the forms of phosphorus 'locked up' in organic debris [106,107]. ...
... There are three types of pistillate line, i.e., N, S, and NES, which could be used for hybrid production. In the N type, the occurrence of only female flowers is controlled by a recessive gene (ff); in the S type, the production of only female flower is controlled by a polygenic complex with dominant and epistatic effects; and in the NES type, the induction of female is also controlled by a recessive gene (ff), but sexual reversion occurs when the air temperature is more than 31°C [105][106][107]. The seed yield and seed oil content are usually inherited by quantitative manner. ...
... 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. ...
It is currently well known and widely accepted that farmers are the general managers
of the Earth’s land surface worldwide. Furthermore, they will continue to shape
agricultural environments in the coming decades. The generation of increased and
improved innovative methodologies and approaches that guarantee the sustainability
of crop production, simultaneously with ecosystem services, is a challenging
scientific area, largely led by ecologists, agronomists, and theoreticians, who must
address this task as a joint effort. Agricultural ecosystems offer a variety of benefits
to the global population, and these are recognized as Ecosystem Services. In this
context, it has been acknowledged that ecosystem services are both actively or passively
engaged in enhancing the well-being of the global population. Accordingly, as
defined in the Millennium Ecosystem Assessment (2005), the main role of agricultural
practices is to support provisioning ecosystem services, mainly through the
manufacture of supplies and educational management. The ecological tools underlying
ecosystem services take into account the complexity of the many possible relationships
between species of economic importance and the characteristics of local
ecosystems. Furthermore, the consequences of biodiversity on the mechanisms
underlying most ecosystem services are nowadays well recognized and known in
most cases, both empirically and theoretically. In an ideal condition, most, if not all,
ecosystem services should also be considered when resource management decisions
are taken and should be included at different scales, both spatial and temporal. It
is also important to avoid overlooking the interactions between biodiversity and
stakeholders, in order to maximize the benefits derived from such practices and
minimize the cost through appropriate decisions. However, relationships between
agricultural practices and ecosystem services are, in most cases, not totally understood.
The ecological mechanisms underlying ecosystem services include multifaceted
interactions not only between organisms, but also among different types of
organisms, and cultural practices and stakeholder strategies can either inhibit or
enhance the ecosystem services. In reality, mechanistic modeling tools examining
the consequences of management options on the provisions of most of the various
ecosystem services are still lacking. There is a need for innovative cropping systems
to be designed at field and landscape scales, and an even larger scales, to aid future
planning, organization, and strategies, in which the complexity of the interactions
encompassed by ecological and decisional networks must be included.
Today, it is accepted worldwide that an AGROECOSYSTEM represents a very
complex environmental system in which many species interact, driving a variety of
ecological processes at different spatial scales. In addition, agroecosystems are characterized
by strong and interrelated interactions among ecological and soil management
processes. These interactions encompass, in a general conceptual framework,
the relationships between ecological and food webs, hosts and pathogens, and
those involving spatial interdependence between localities. Under this scenario, an
“interaction networks” model enables researchers in the field to (1) analyze and
understand the emergent properties of complex systems, and (2) develop universal
rules that allow individual stakeholders to make decisions regarding the outcomes
of the ecosystem.
IV
This book, “Agroecosystems – Very Complex Environmental Systems,” aims to present
an update on different aspects associated with the importance of sustainable agriculture.
It was our intention to gather information from diverse sources in this volume
and to give some real-life examples, extending the appreciation of the complexity of
this subject in a way that may stimulate new approaches in relevant fields.
This book includes seven general chapters highlighting different aspects of agroecosystems
worldwide. The first chapter describes the fungal endophytes of Australian
orchid species; these endophytes exploit large areas of the soil, to which orchid
roots have no access, and acquire both organic and inorganic nutrients beyond
the depletion zone at low carbon cost. Several integrated approaches have been
developed for the conservation, management, and restoration of these terrestrial
orchids in the wild because appropriate conservation priorities need to be established
urgently to prevent the loss of habitats for these endangered species. This
chapter also focuses on the protection of these endangered Australian orchid species
by developing an understanding of the nutritional behaviour of their endophytes.
The second chapter aims to describe the impact of the plant hormone brassinolide
on two varieties of fig from Indonesia and Malaysia, stressing the significant effect
of interactions between brassinolide and diversity on fig growth and physiological
changes, except in respect of plant height and dry biomass. The third chapter documents
the relationship between resistant varieties of hybrid strawberries Fragaria
× ananassa Duch. and negative environmental conditions. These conditions include
physiological and biochemical indicators of resistance during autumn hardening
and after temperature stress in winter that resulted in changes in the antioxidant
system, interruptions of the protein-carbohydrate complex, accumulation of
membrane lipoperoxidation products, and changes in the fractional composition
of water in the leaves. The fourth chapter has been written to provide botanical
descriptions of the castor bean or castor oil plant, belonging to the monotypic
genus Ricinus, describing its ecology, agro-technology, and many industrial uses. At
present the plant is in increasing demand in the international market for its more
than 700 uses, ranging from medicine and cosmetics to biodiesel, plastics, and
lubricants. The fifth chapter is focused on the development of a defined, highlyreliable,
and integrated methodology for identifying the causes of contamination
of agroecosystems in southern Italy, namely asbestos and illegal burial of waste,
in the soil as well as microplastic pollution. This chapter also discusses innovative
and high-speed approaches to obtaining ever more precise data on environmental
degradation. The sixth chapter is an update on the literature regarding the use of
deep eutectic solvents to treat lignocellulosic wastes within the field of biomass
valorization. Therefore, this chapter emphasizes how the preparation of novel deep
eutectic solvents and improving treatment conditions will help to solve the environmental
problems originating from agro-industrial wastes and also to develop new
platforms for the production of valuable products such as chemicals, biofuels, and
bioactive phenolic compounds. Finally, this book includes a chapter that discusses
the effects of the application of blue-green algae, which enhances the morphological
and photosynthetic efficiency of the rice plant under greenhouse conditions,
stressing that the application of such a bio-mixture in agriculture not only increases
crop yield but also maintains our environment sustainably.
Finally, as indicated in a book we published some years ago, entitled “Organic
Fertilizers – From Basic Concepts to Applied Outcomes”, it seems obvious “that future
agricultural practices will irreversibly shape the Earth’s land surface, including its
species, geochemistry, and disponibility of surface to the people living on it”. We
hope that the information presented in this book will be of value to those directly
XIV
V
engaged in the management and use of agroecosystems, and that this book will
continue to meet the expectations and needs of all those interested in the different
ways that agroecosystems can be directed to achieve sustainable agriculture without
compromising environmental integrity.
The chapters provided by the authors in this field of research are gratefully
acknowledged. The publication of this book is orientated to those researchers, scientists,
engineers, teachers, graduate students, agricultural agronomists, farmers,
and crop producers who can use these different results to develop an understanding
of the complexity of an agroecosystem and the different aspects and relationships
among the different entities involved. The concepts of agroecosystems and ecosystem
services can help scientists determine how much of each service is provided
throughout the many scales of the networks (field, farm, and/or landscape) at the
different ecological levels (individuals, species, communities, and ecosystems),
allowing innovative strategies to be developed in ecosystem services management
and the damage caused by agroecosystems to be minimized.
... It was found that the water content in different choline chloride-based DES influences the oxidation, while the extraction time and temperature showed no significant impact. Heat-stirring assisted extraction (HSE) or ultrasound probe-assisted extraction was used along with deep eutectic solvents for preparing extracts rich in phenolics and alkaloids [14]. It was found that ultrasound (3 min, 200 W) DES (lactic acid:ChCl) was superior in extracting the compounds (chlorogenic acid, caffeine, and theobromine) compared to HSE. ...
... These bioactive compounds showed remarkable biological activities, which could provide functionality to food products ( Figure 2). R PEER REVIEW 9 of 15 extraction was used along with deep eutectic solvents for preparing extracts rich in phenolics and alkaloids [14]. It was found that ultrasound (3 min, 200 W) DES (lactic acid:ChCl) was superior in extracting the compounds (chlorogenic acid, caffeine, and theobromine) compared to HSE. ...
Cocoa husk is considered a waste product after cocoa processing and creates environmental issues. These waste products are rich in polyphenols, methylxanthine, dietary fibers, and phytosterols, which can be extracted and utilized in various food and health products. Cocoa beans represent only 32–34% of fruit weight. Various extraction methods were implemented for the preparation of extracts and/or the recovery of bioactive compounds. Besides conventional extraction methods, various studies have been conducted using advanced extraction methods, including microwave-assisted extraction (MAE), ultrasonic-assisted extraction (UAE), subcritical water extraction (SWE), supercritical fluid extraction (SFE), and pressurized liquid extraction (PLE). To include cocoa husk waste products or extracts in different food products, various functional foods such as bakery products, jam, chocolate, beverage, and sausage were prepared. This review mainly focused on the composition and functional characteristics of cocoa husk waste products and their utilization in different food products. Moreover, recommendations were made for the complete utilization of these waste products and their involvement in the circular economy.
... A biorefinery approach was engaged by Ruesgas-Ramón et al., to isolate phenolic acids from coffee and cocoa by-products. [39] Coffee and cocoa consumption generates solid wastes, such as pulp and husk, which represents million tons of waste. Coffee pulp represents around 40% of the fresh weight of coffee fruits, whereas cocoa husk and cocoa pod husk are the main co-products from the cocoa manufacturing. ...
... The study carried out by Ruesgas-Ramón et al. [39] focused on the investigation of six NaDES based on Choline Chloride or Betaine as HBA for polyphenol extraction. Two different extraction conditions were compared: ultrasound-probe assisted extraction and heat stirring-assisted extraction. ...
With the growing interest in more environmentally friendly solvents and processes, the introduction of Natural Deep Eutectic Solvents (NaDES) as low cost, non-toxic and biodegradable solvents represent a new opportunity for green and sustainable chemistry. Thanks to their remarkable advantages, NaDES are now arousing growing interest in many fields of research such as food, health, cosmetics and biofuels. Around the world, NaDES are seen as a promising alternative to commonly used petrochemical solvents. The objective of this review is to draw up a panorama of the existing skills on NaDES in French laboratories and industries for the valuation of natural products. This review therefore focuses on current applications, skills and perspectives, in order to analyze the place of French research in the use of NaDES for the valorization of biomass since 2015.
... Silva et al. [15] extracted phenolic compounds with ethanol and water: ethanol mixtures. Ruesgas-Ramon at al. [46] used deep eutectic solvents, whereas Andrade et al. [47] employed supercritical fluids to extract phenolic compounds from the coffee husk. The aqueous extract presented concentrations similar to those obtained with eutectic solvents but much lower than those obtained with ethanol and supercritical carbon dioxide. ...
... A comprehensive analysis was carried out to find 18 compounds, including hydroxybenzoic, hydroxycinnamic, phenylacetic acids, monomeric and dimeric flavan-3ols, and flavonols. Previous studies have been focused on the main phenolic compounds (chlorogenic, protocatechuic, gallic, and caffeic acids) and the caffeine content [15,46,47]. ...
This study aimed to model and optimize a green sustainable extraction method of phenolic compounds from the coffee husk. Response surface methodology (RSM) and artificial neural networks (ANNs) were used to model the impact of extraction variables (temperature, time, acidity, and solid-to-liquid ratio) on the recovery of phenolic compounds. All responses were fitted to the RSM and ANN model, which revealed high estimation capabilities. The main factors affecting phenolic extraction were temperature, followed by solid-to-liquid ratio, and acidity. The optimal extraction conditions were 100 °C, 90 min, 0% citric acid, and 0.02 g coffee husk mL−1. Under these conditions, experimental values for total phenolic compounds, flavonoids, flavanols, proanthocyanidins, phenolic acids, o-diphenols, and in vitro antioxidant capacity matched with predicted ones, therefore, validating the model. The presence of chlorogenic, protocatechuic, caffeic, and gallic acids and kaemferol-3-O-galactoside was confirmed by UPLC-ESI-MS/MS. The phenolic aqueous extracts from the coffee husk could be used as sustainable food ingredients and nutraceutical products.
... 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. ...
... 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]. ...
The growing interest of the food, pharmaceutical and cosmetics industries in naturally
occurring bioactive compounds or secondary plant metabolites also leads to a growing demand for
the development of new and more effective analysis and isolation techniques. The extraction of
bioactive compounds from plant material has always been a challenge, accompanied by increasingly
strict control requirements for the final products and a growing interest in environmental protection.
However, great efforts have been made in this direction and today a considerable number of
innovative extraction techniques have been developed using green, environmentally friendly solvents.
These solvents include the deep eutectic solvents (DES) and their natural equivalents, the natural
deep eutectic solvents (NADES). Due to their adjustable physical-chemical properties and their green
character, it is expected that DES/NADES could be the most widely used solvents in the future,
not only in extraction processes but also in other research areas such as catalysis, electrochemistry or
organic synthesis. Consequently, this review provided an up-to-date systematic overview of the use
of DES/NADES in combination with innovative extraction techniques for the isolation of bioactive
compounds from various plant materials. The topicality of the field was confirmed by a detailed
search on the platform WoS (Web of Science), which resulted in more than 100 original research papers
on DES/NADES for bioactive compounds in the last three years. Besides the isolation of bioactive
compounds from plants, different analytical methods are presented and discussed.
... ChCl:Malic acid Water HPLC-DAD Phenolic compounds 49.70 mg g [219] coffee and cocoa 44.2 ± 1.09 g/100 g [220] Rosmarinus officinalis L. [221] Extra-virgin olive oil mg/g [222] Moringa oleifera L. [223] Chinese dark tea ChCl:Lactic acid 70 wt% DELs aqueous solution. ...
Deep Eutectic Liquids (DELs) fall among the rapidly evolving discoveries of the 21st century, and these liquids are considered as alternative solvents to toxic and volatile organic liquids. Nevertheless, the emerging trend regarding the use of DELs in every field of physical and biological sciences, a lot of ambiguities and misconceptions exist about their formation, mechanism, and efficiencies observed or projected. A review of available technical data makes it obvious that these liquids have the potential to revolutionize the underdeveloped areas of analytical chemistry particularly the extraction/enrichment of analytes. To ensure the green and sustainable use of DELs, the researchers need to have a thorough understanding of DELs, their classification, chemistry, the nature and strength of molecular entanglements, and their tailorable features. Many researchers have declared these liquids recyclable but more attentive trials are needed to develop an authentic and straightforward DELs recycling methodology. The present review covers sound background knowledge and expert opinions about the technical definition of DELs, their classification, formation, recyclability, and tailorable features for their application as extraction solvent/sorbent in analytical chemistry.
... Hence, the optimal ratio between water and ethanol is often a subject of UAE optimization. Recently, there has been increasing interest to extract polyphenols using natural deep eutectic solvents, considered as promising green solvents (Ruesgas-Ramón et al., 2020;Zurob et al., 2020). ...
Phenolics are among the most studied compounds due to their beneficial implications in human health. The conventional methods applied in the extraction of these compounds include maceration, distillation, Soxhlet, among others, and the extraction capacity depends on several factors, such as the extraction solvent and respective concentration, time, and temperature. The incorporation of green chemistry in the development of more sustainable products and processes has promoted the use of new solvents that would replace conventional ones and the application of more eco-sustainable technologies (e.g., supercritical fluids, pulsed electric fields, and ultrasounds). Green solvents, coupled with conventional extraction methods, present excellent stability for food, pharmaceutical, and cosmetic industries because they are non-toxic, non-volatile, recyclable, biodegradable, and imply lower energy cost of synthesis. In this chapter, traditional and eco-sustainable methods based on solid–liquid extraction will be revised, as well as safety issues, life-cycle assessment, and economic aspects.
... Após a colheita, os frutos são abertos ou quebrados, ainda no campo, e os grãos são retirados junto com a polpa (ROJO-POVEDA et al., 2020). Da pós-colheita à produção de grãos secos, a indústria do cacau gera uma quantidade significativa de resíduos agroindustriais, como a casca de vagem, polpa e casca de sementes (RUESGAS-RAMÓN et al., 2019). A busca por subprodutos do cacau por parte de empresas ao redor do mundo representa um novo segmento industrial, direcionado ao reaproveitamento do resíduo para o desenvolvimento de diversos produtos para diferentes fins, como nutrição animal, fertilizantes e suplementos (Okiyama;NAVARRO;RODRIGUES, 2017). ...
Os produtos à base de cacau são classificados como altamente energéticos, estimulantes e antioxidantes devido ao alto teor de gordura e compostos bioativos. Por conta disso, o presente trabalho tem como objetivo investigar o potencial para o desenvolvimento de novas bebidas fermentadas funcionais contendo cacau por meio do levantamento de patentes. Para isso, uma pesquisa foi realizada a partir da combinação de palavras-chave com o Código Internacional de Patentes (CIP) no banco de dados do Derwent (DWPI). O ano de 2019 demonstrou o maior registro de publicações, ampliando as buscas de produtos com efeitos funcionais para a saúde. A Organização Mundial da Propriedade Intelectual (OMPI) e o Escritório Europeu de Patentes (EP) possuem a maior quantidade de proteção patentária, os quais incluem registros em diferentes países. Além disso, observou-se que grande parte dos documentos de patentes encontra-se relacionada a compostos em pó para aplicação em produtos farmacêuticos, nutracêuticos ou bebidas.
... Coffee is one of the most popular hot drinks in the world, with three times as much coffee consumed as cocoa and four times as much as tea (Ruesgas-Ramón et al., 2020). In 2016, the coffee yield was 1.60 × 10 8 kg and the export of beans was 8.27 × 10 7 kg (export value of USD 9.04 × 10 8 ) in China (Liu et al., 2018). ...
Reasonable water and light management technology can improve economic benefits, coffee yield, and quality. We used cluster analysis and principal component analysis to evaluate and optimize the water and light management technology with high coffee yield, quality, and economic benefits in a subtropical monsoon climate region of China. The experiment was arranged in a randomized complete block design with two factors (3 irrigation levels × 4 shade cultivation treatments) replicated four times during 2016–2017. The irrigation levels consisted of full irrigation (FI) and two deficit irrigations (DIL: 75% FI, DIS: 50% FI). The shade cultivation treatments consisted of no shade cultivation (S0) and three shade cultivation modes (SL: intercropping with four lines of coffee and one line of banana; SM: intercropping with three lines of coffee and one line of banana; SS: intercropping with two lines of coffee and one line of banana). The results showed that the effects of irrigation level and shade cultivation mode on growth, crop yield, most of the photosynthetic characteristics, and nutritional quality were significant (p < 0.05). Regression analysis showed that the leaf radiation use efficiency (RUE) showed a significant negative exponential relation or logistic-curve variation with photosynthetically active radiation (PAR). The bean yield increased with an increase of the shade degree when water was seriously deficient, whereas it first increased and then decreased with an increase of the shade degree under FI and DIL. Based on both cluster analysis and principal component analysis, the FISS treatment resulted in the highest comprehensive quality of coffee, followed by the FISM treatment; the DISS0 treatment obtained the lowest quality. Compared with the FIS0 treatment, the FISM treatment increased the 2-year average bean yield and net income by 15.0 and 28.5%, respectively, whereas the FISS treatment decreased these by 17.8 and 8.7%, respectively. To summarize, FISS treatment significantly improved the nutritional quality of coffee, and FISM treatment significantly increased the dry bean yield and economic benefits of coffee. The results of the study could provide a theoretical basis for water-saving irrigation and shade cultivation management of coffee in a subtropical monsoon climate region of China.
... Previous studies have also investigated the extraction of compounds from coffee by-products using ultrasound-assisted and supercritical extractions and organic or deep eutectic solvents. Similarly, the major phenolic compounds found were chlorogenic, protocatechuic, gallic, and caffeic acids, and the caffeine content was remarkable (35)(36)(37). Thus, the primary bioactive compounds present in CSE and CHE were considered as treatments used in the form of standard solutions for the following analyses (kaempferol was tested as aglycone, being the latter the bioavailable form). ...
Coffee by-products contain bioactive compounds that have been shown to have the capacity to modulate human metabolism. The goal of this study was to investigate the effects of the main bioactive compounds in coffee by-products and two aqueous extracts from the coffee husk and silverskin on the activation of fibroblast growth factor 21 (FGF21) signaling and the subsequent regulation of mitochondrial bioenergetics and lipid and glucose metabolism. HepG2 cells treated with palmitic acid (PA) were used in a non-alcoholic fatty liver disease (NAFLD) cell model. The bioactive compounds from coffee by-products (50 µmol L −1) and the aqueous extracts from the coffee silverskin and coffee husk (100 µg mL −1) increased ERK1/2 phosphorylation and the secretion of FGF21 (1.3 to 1.9-fold). Coffee by-products' bioactive compounds counteracted inflammation and PA-triggered lipotoxicity. Oxidative stress markers (ROS, mitochondrial superoxide, and NADPH oxidase) and the activity of antioxidant enzymes (superoxide dismutase and catalase) were modulated through the activation of Nrf2 signaling. Mitochondrial bioenergetics were regulated by enhancing respiration and ATP production via PGC-1α, and the expression of oxidative phosphorylation complexes increased. Coffee by-products' bioactive compounds decreased lipid accumulation (23-41%) and fatty acid synthase activity (32-65%) and triggered carnitine palmitoyltransferase-1 activity (1.3 to 1.7-fold) by activating AMPK and SREBP-1c pathways. The GLUT2 expression and glucose uptake were increased (58-111%), followed by a promoted glucokinase activity (55-122%), while glucose production and phosphoenolpyruvate carboxykinase activity were reduced due to IRS-1/Akt1 regulation. The bioactive compounds from coffee by-products, primarily chlorogenic and protocatechuic acids, could regulate hepatic mitochondrial function and lipid and glucose metabolism by activating FGF21 and related signaling cascades.
... The aqueous phase of the Folch extraction was evaporated with nitrogen flow, resuspended with 1 mL of MeOH/water (2:1, v/v), and filtered (0.45 µm, cellulose filter). Samples (40 µL) were injected in the HPLC (LC-20 CE equipped with oven CTO-10ASvp and detector DAD SPO-M20, Shimadzu, Noisiel, France) [32] with the gradient method (mobile phase A: MeOH and B: water, both with 0.1% acetic acid): 0-5 min: isocratic at 10% of B; 5-20 min: linear gradient up to 100% B; 20-30 min isocratic at 100% B; 30-35 min linear gradient up to 10% B; 35-42 min: equilibration at 10% B. The detection was performed at 280 nm and 330 nm. Gallic acid (GA) was used for the calibration curve quantification, and data were expressed in mg eq of GA. ...
Natural Deep Eutectic solvents (NaDES) was used to produce, after sequential one-pot extraction and biotransformation of naturally pigmented rice bran (RB), ready-to-use extracts that improve the oxidative stability of lipids in an oil-in-water emulsion. Two NaDES-based strategies were implemented. Extraction of phenolics content varied according to the NaDES. The shiftable NaDES (obtained from the acidic-NaDES based on ChCl and xylitol) stands out by showing content of 1525 mg eq gallic acid/100 g RB. The sequential one-pot biotransformation with immobilized Candida antarctica lipase B after increasing pH, was marked by a decrease in phenolics content and a lipids profile variation. These enriched extracts could be used as natural additives or ready-to-use extracts, as confirmed by the encouraging antioxidant results observed in emulsion. Omics tools should be applied to elucidate the structural rearrangement between compounds and the pool of extracted antioxidant molecules that may explain the protection against lipid oxidation.
... Caffeine and theobromine were identified in the extracts of coffee pulp and cocoa hush, promising results were obtained using choline chloride: lactic acid:water (1:2:1.5), with yields of 0.53 g of caffeine/100 g of coffee pulp and 0.65 g pf theobromine/100 g cocoa hush, respectively (Ruesgas-Ramón et al., 2020). ...
A new methodology for the selective extraction of antioxidants from mate tea leaves (and decaffeinated mate tea leaves), using different natural deep eutectic systems (NADES), is reported in this paper. A fractionated extraction was carried out and the optimization of the extraction conditions such as solid/liquid ratio, temperature, time, stirring and the use of ultrasound assisted extraction (UAE) technology was performed. The results demonstrate that a sequential extraction using, in a first step, an hydrophobic system Men:Lau (2:1) and, in a second step, an hydrophilic lactic acid-based NADES, leads to two distinct extracts: the first one rich in pigments and the second one rich in polyphenols.
NADES systems were able to extract 30% more of the polyphenolic components of the mate tea leaves matrices, when compared with traditional solvents/techniques. Moreover, it has been shown that the incorporation of the extract in the NADES, compared to the same extract in aqueous medium was beneficial for the stabilization of the antioxidants. It maintains their functionality at least for three months, reaching 41% more versus the extracts obtained by traditional solvents/techniques. The absence of caffeine in the extracts did not shown to have any effects on the stability results.
... 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. ...
The agri-food sector produces a huge amount of agri-food wastes and by-products, with a consequent great impact on environmental, economic, social, and health aspects. The reuse and recycling of by-products represents a very important issue: for this reason, the development of innovative recovery and extraction methodologies must be mandatory. In this context of a circular economy, the study of green extraction techniques also becomes a priority in substitution of traditional extraction approaches. This review is focused on the recovery of chlorogenic acids from agri-food wastes, as these compounds have an important impact on human health, exhibiting several different and important healthy properties. Novel extraction methodologies, namely microwave and ultrasound-assisted extractions, supercritical fluid extraction, and pressurized-liquid extraction, are discussed here, in comparison with conventional techniques. The great potentialities of these new innovative green and sustainable approaches are pointed out. Further investigations and optimization are mandatory before their application in industrial processes.
... From an environmental point of view, chemicals from natural sources such as organic acids (Choi et al., 2011), sugars and sweeteners (Carter et al., 2004;Nockemann et al., 2007) and amino acids (Kagimoto et al., 2006), have been considered in DESs composition as starting materials. DESs can be used for many applications including the separation of mixtures (Jiao et al., 2019), desulfurization of fuels (Ahmed Rahma et al., 2017;Li et al., 2019), and extraction of interesting compounds from biological tissues (Benvenutti et al., 2020;Cai et al., 2019;He et al., 2020;Kanberoglu et al., 2019;Ruesgas-Ramón et al., 2020;Saha et al., 2019). ...
Leptospermum scoparium (Manuka) is a small indigenous shrub belonging to the family of Myrtaceae, which is equivalent to a tea tree (Melaleuca alternifolia) in Australia. Manuka leaves are rich in bioactive terpenes such as β-caryophyllene, which are scientifically proven to have potential activities in different areas including antimicrobial, anti-inflammatory, antitumour, antioxidant, and anaesthetic. This research considers for the first time the application of deep eutectic solvents (DESs) as green and sustainable solvents for the extraction of β-caryophyllene (β-CAR) from New Zealand Manuka leaves. The extraction was carried out using twenty-six types of hydrophilic and hydrophobic DESs. Menthol: Lactic acid DES was found to have higher extractability of β-caryophyllene than n-hexane, methanol, and ethanol as reference solvents. Moreover, Menthol: Lactic acid DES at 1:2 molar ratio was more efficient than conventional steam distillation and Soxhlet extraction. Furthermore, β-caryophyllene showed a good stability in menthol: lactic acid DES over 9 days of storage. The final β-caryophyllene concentration (β-CAR= 8.713605 mg/g Manuka leaf) after 4 cycles of extraction suggests a good reusability of the potential DES. The extraction of β-caryophyllene using this DES was further optimised using RSM (response surface methodology) combined with BBD (Box-Behnken design). The optimum experimental conditions were as follows: temperature 25.07 °C, stirring time 1.09 h, and % w/v biomass of 14.99%, which gave an extraction yield of 10.25 mg of β-caryophyllene/g Manuka leaf.
... Due to their excellent properties such as high biodegradability, low toxicity as well as simple and inexpensive preparation, NADESs have already found applications in different research areas, in organic synthesis and biosynthesis (Wu et al., 2019b), electrochemistry (Brett, 2018) and materials science (Tomé et al., 2018). Furthermore, recent publications have shown that NADESs can be successfully used in combination with UAE for the enhanced and greener extraction of phenolics from various matrices: wine less and grape skin (Cvjetko Bubalo et al., 2016), olive pomace (Chanioti and Tzia, 2018), citrus and pomegranate peels (Xu et al., 2019), rosemary (Barbieri et al., 2020), food by-products (Fernández et al., 2018;Ruesgas-Ramón et al., 2020) and others Ş ahin, 2019). Certainly, one of the main advantages of NADESs is their diversity and tunability as they can be prepared by many combinations of hydrogen donor/ hydrogen acceptor pairs, resulting in tailor-made solvents for the selective extraction of the target compound groups (Xu et al., 2019). ...
In the present study, an analytical methodology based on natural deep eutectic solvents (NADESs) and ultrasound-assisted extraction (UAE) is demonstrated as an environmentally friendly protocol for the isolation of valuable phenolic compounds from inflorescences of Helichrysum arenarium L. For this purpose, 11 different NADESs containing choline chloride and selected hydrogen bond donors, including organic acids, polyols, sugars and an amide, were tailored and evaluated based on the content of individual compounds determined by HPLC-PDA-MS n. Choline chloride-lactic acid based NADES (NADES 1) showed the most promising extraction effi-ciencies for flavonoids (15.34 ± 0.10 mg g − 1) and phenolic acids (5.10 ± 0.12 mg g − 1) as the efficiencies were comparable to those obtained with 80 % methanol (15.60 ± 0.09 mg g − 1 and 5.32 ± 0.18 mg g − 1 , respectively) and up to 54 % higher compared to water (9.94 ± 0.13 mg g − 1 and 5.47 ± 0.22 mg g − 1). Furthermore, three essential parameters of the proposed NADES 1 methodology (UAE time, water content in NADES, and NADES hydrogen donor/acceptor molar ratio) were optimized by Box-Behnken experimental design. Based on the statistically evaluated results the following conditions were determined to be optimal: an UAE time of 85 min, 38 % water in NADES 1, and a molar ratio of choline chloride:lactic acid of 1:4. The developed approach allows easy transfer of the proposed methodology to large-scale extraction, enabling clean production with minimal environmental impact.
... It observed that lactic acid:choline chloride (2:1 mol ratio) was the most promising DES. It also found a higher extraction yield using ultrasound-probe assisted extraction at 200 W than the heat stirringassisted extraction (Ruesgas-Ramón et al., 2020). A series of DESs (e.g. ...
Food processing industries produce a huge amount of heterogeneous by-products in different processing operations while converting raw materials into final products. The extraction-based value addition of these by-products is an important step for waste minimization. In this context, it is desirable to approach greener extraction alternatives using smart solvents like ionic liquids and deep eutectic solvents. These solvents may potentially replace conventional solvents due to their biocompatibility, low toxicity and recyclability. Also, these solvents have tunable properties needed for specific selectivity of a particular bioactive compound. This paper delivers information regarding different types of neoteric solvents (fluorous solvents, ionic liquids and deep eutectic solvents) and their application in the extraction of high-value compounds from food processing by-products.
... 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. ...
Lignocellulose is the most abundant component in nature since it refers to plant material. Beyond the enormous utilization of lignocellulose by human being, unignorable amount of waste is also formed simultaneously. Agro-industrial lignocellulosic wastes can cause environmental pollutions if not processed before discharged. An innovative approach for lowering the detrimental influences of lignocellulosic wastes is to consider them as a source of useful products rather than a waste to be decontaminated. Beyond the conventional techniques for evaluation of the wastes, new emerging techniques and the use of new solvents have drawn attention recently. Among new generation solvents, deep eutectic solvents (DESs) have been increasingly used in the treatment of lignocellulosics to produce value-added products such as biofuels, chemicals, and solvents and also used for the recovery of bioactive phenolic compounds. DESs are used extensively for fractionation of lignocellulosic wastes, often in combination with enzymatic hydrolysis of the biomass. On the other hand, extraction and recovery of bioactive compounds are also under research using DESs. This mini review summarizes the very recent literature reports on the use of DESs in treating agro-industrial wastes within the concept of valorization of biomass.
... There are several methods and procedures to change the composition of the original lignocellulosic matrix aimed at eliminating one of its components (lignin or polysaccharides), thus obtaining new products (pulp, microcrystalline cellulose, nanocellulose etc.), and valorizing the biomass. These include processes such as solubilisation, extraction, fractionation, deconstruction, delignification, and post-delignification [1,13,28,[33][34][35][36][37][38][39][40][41]. Value-added substances and compounds are isolated from biomass by extraction techniques using predominantly water and common organic solvents, and, to a minor extent, eco-friendly green solvents represented by deep eutectic solvents [13]. ...
Extracts from spruce bark obtained using different deep eutectic solvents were screened for their total phenolic content (TPC) and antioxidant activities. Water containing choline chloride-based deep eutectic solvents (DESs) with lactic acid and 1,3-propanediol, 1,3-butanediol, 1,4-butanediol, and 1,5-pentanediol, with different molar ratios, were used as extractants. Basic characteristics of the DESs (density, viscosity, conductivity, and refractive index) were determined. All the DESs used behave as Newtonian liquids. The extractions were performed for 2 h at 60 °C under continuous stirring. TPC was determined spectrophotometrically, using the Folin-Ciocalteu reagent, and expressed as gallic acid equivalent (GAE). The antioxidant activity was determined spectrophotometrically by 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging assay. The TPC varied from 233.6 to 596.2 mg GAE/100 g dry bark; radical scavenging activity (RSA) ranged between 81.4% and 95%. This study demonstrated that deep eutectic solvents are suitable solvents for extracting phenolic compounds from spruce bark.
The green solvents and eco‐extraction methods are gaining increasing interest in chemical analysis for bioactive compounds in food matrices. Deep Eutectic Solvents (DES) developed as a greener and more sustainable alternative to organic solvents, owing to their non‐toxic, highly stable, and biodegradation‐friendly nature. DES application for polyphenols and antioxidant compounds extraction in dark chocolate samples has been evaluated in an integrated study for sustainability assessment, based on multivariate analysis and Life Cycle Assessment (LCA) methodology. A green extraction method based on DES was proposed testing different HBA:HBD pairs (ChCl:Fru, ChCl:Teg, Bet:Fru, and Bet:Teg). DES Bet:Fru resulted in the highest extraction yield in terms of both total polyphenols (0.34‐3.37 g GAE/100g), and flavonoids (1.13‐8.32 g RUT/100g), p<0.05. Furthermore, the environmental performances of green and conventional solvents (MeOH:H2O, H2O, and MeOH) were evaluated by applying a comparative LCA (c‐LCA). The c‐LCA study highlighted that conventional extraction for polyphenols in dark chocolate was 60% more impactful than DES. DES pairs analyzed quantitatively lowest impacted than conventional methods, considering the macro‐categories Human Health (9.99 x 10‐8 ÷ 1.54 x 10‐7 DALYs), Ecosystem (2.29 x 10‐10 ÷ 3.57 x 10‐10 species.yr), and Resources (6.57 x 10‐3 ÷ 8.96 x 10‐3 USD2013).
This review article aims to study how phytochemists have reacted to green chemistry insights since 1990, the year when the U.S. Environmental Protection Agency launched the "Pollution Prevention Act". For each year in the period 1990 to 2019, three highly cited phytochemistry papers that provided enough information about the experimental procedures utilized were sampled. The "greenness" of these procedures was assessed, particularly for the use of solvents. The highly hazardous diethyl ether, benzene, and carbon tetrachloride did not appear in the papers sampled after 2010. Advances in terms of sustainability were observed mainly in the extraction stage. Similar progress was not observed in purification procedures, where chloroform, dichloromethane, and hexane regularly have been employed. Since replacing such solvents in purification procedures should be a major goal, potential alternative approaches are discussed. Moreover, some current initiatives toward a more sustainable phytochemical research considering aspects other than only solvents are highlighted. Although some advances have been achieved, it is believed that natural products chemists can play a major role in developing a novel ecological paradigm in chemistry. To contribute to this objective, six principles for performing natural products chemistry consistent with the guidelines of green chemistry are proposed.
The need to reduce the ecological impact of the extraction and analysis processes waste has led to use alternative green solvents. Therefore, the use of solvents such as deep eutectic solvents (DESs), natural deep eutectic solvents (NADESs), and low transition temperature mixtures (LTTMs) has increasingly applied to extraction and recovery of bioactive molecules. DESs show superior extraction capabilities compared to common organic solvents, both in terms of extraction yield and nature of extractable molecules with a single solvent. However, one of the major problems with this type of solvents is the difficulty to remove them from the extracted mixture due to their low vapor pressure and thus recovering analytes to be used. This review aims to provide an overview of the methods for recovery bioactive molecules from extracts obtained by the application of DESs and NADESs to various food and plant matrices. Methods are critically presented both concerning efficacy and eco-compatibility.
Across the world, an enormous amount of agricultural waste is generated in the excess of 2 billion tons. Such waste with diverse characteristics is the good source of bioactive compounds that are extracted without altering their properties through deep eutectic solvents. The deep eutectic solvents are composed of two or three components which are capable of self-association with a melting point lower than that of each individual component which develop the interest as a good alternative to organic solvents. These solvents are becoming greener alternatives for the extraction because of their tailor-made properties like the possibility of the formulation according to specific applications. In this review, we summarize the main contributions of DESs as sustainable benign diluents to extract bioactive components such as polyphenols, proteins, carbohydrates, alkaloids etc. from the agro-industrial by-products. This work also presents the physicochemical properties, factors affecting the extraction process along with safety and environmental effects of DESs.
In this chapter, an updated overview on the applications of ultrasound (US) technology (as pretreatment or during the extraction process) to recover valuable phenolic compounds from agro-food by-products and wastes is presented. The principle of sonication, its effects on vegetal matrix and extraction mechanisms provoked by US application, the types of equipment used for ultrasound-assisted extraction (UAE), as well as the advantages and the limits of this technology, especially regarding green extraction principles, are presented. Parameters influencing UAE efficiency, as well as modeling and optimization of the process, are also discussed. Then we focus on the application of UAE for polyphenols recovery from various by-products and wastes. Aspects related to the safety and environmental issues and scale-up of UAE process are also presented. Finally, future trends for application of US technology for valorization of agro-food wastes by extracting valuable phenolics are discussed.
The objective of this work was the development of a green extraction method based on the use of a deep eutectic solvent (DES) to extract caffeine from coffee pulp (CP). Choline chloride and glycerol were used as hydrogen bond acceptor and hydrogen bond donor, respectively. ATR-FTIR and viscosity measurements were conducted for the characterization of DES mixtures. The effects of DES mixtures concentration (CDES), liquid-to-solid ratio (L/S), extraction temperature (T) on caffeine extraction yield (CCaf) and extract antiradical activity (AAR) were studied, and the extraction process was optimized. The optimum of extraction was achieved at a temperature of 55 °C, a solvent/pulp ratio of 47 mL/g, and a DES concentration of 70% w/v in aqueous solution. In addition, a mathematical model to describe the kinetic mechanisms of the extraction was developed, whereas the dependence of the best descriptive model constants on extraction variables was expressed by an appropriate model. These results would offer scientific reference for promoting the valorization of coffee pulp.
Bio-oil is an important candidate to replace oil-derived products since it origins from renewable sources such as biomass. However, oxygenated bio-oil-based compounds require upgrading and further separation and purification for obtaining valuable compounds. Guaiacol is an important lignin derivative obtained from bio-oil, and it is a precursor for obtaining high-value-added molecules through heterogeneous catalysis. Alkanes are typical solvents for the guaiacol catalytical upgrading, so it is important to understand the extraction of guaiacol or guaiacol-like molecules from alkanes systems. This work reports the potential applicability of glycols and their corresponding eutectic mixtures with choline chloride as liquid-liquid extracting agents of guaiacol from n-hexane. The liquid-liquid equilibrium of six ternary systems composed of guaiacol + n-hexane + glycol or eutectic mixture is reported at 313.15 K and 101.3 kPa. Glycols selected as hydrogen bond donors were ethylene glycol, 1,2-propanediol, and 1,4-butanediol, while choline chloride was chosen as the hydrogen bond acceptor for preparing three eutectic mixtures using the glycols mentioned earlier. Density and viscosity of pure components and binary mixtures composed of guaiacol + glycols or guaiacol + eutectic mixture were measured at temperatures between 293.15 K and 333.15 K at 101.13 kPa. Density and liquid-liquid equilibrium data were modeled with PC-SAFT, and binary parameters were only used between the studied glycols and guaiacol. The results showed that the constituents of the eutectic mixtures did not distribute in the n-hexane phase, which was validated by NMR and GC. The viscosity of the pure components was correlated using PC-SAFT + Free Volume Theory, which allowed predicting the viscosity of mixtures by using binary parameters that were fitted to viscosity-independent data. The results obtained show that there is a high affinity between the guaiacol and the eutectic mixtures, based on observations about the negative excess volumes and the liquid-liquid equilibria. The eutectic mixtures are better for extracting guaiacol than their respective glycol-based constituents since they have higher selectivity and distribution coefficients and are larger miscibility gaps with the n-hexane phase compared to the studied glycols.
O objetivo deste trabalho foi avaliar a composição nutricional, caracterizar e correlacionar os parâmetros de qualidade da polpa do cacau. A amostra analisada foi a polpa dos frutos do cacaueiro dos genótipos CCN51 e CEPEC 2005, denominada comercialmente de blend. Foram avaliadas a composição centesimal aproximada, valor calórico, características físicas, físico-químicas, químicas e correlação dos parâmetros analisados. A polpa apresentou baixo valor calórico (56,19 Kcal), alto teor de sólidos solúveis (20,40ºBrix), ratio (32,45) e potássio (128,61mg/100g). Além de correlações muito forte (r±0,91 a ±1,00) e forte (r±0,71 a ±0,90) ao nível de 5% de significância entre as características ratio, sólidos solúveis, Aw, açúcares totais, amido, densidade e vitamina C. A amostra apresenta potencial de utilização para desenvolvimento de produtos alimentícios, pois contém importante composição centesimal, resultados expressivos para o teor de sólidos solúveis, ratio, açúcares totais e redutores e valor calórico relativamente baixo, podendo ser adicionada em dietas, suplementação alimentar, como também em processamentos tecnológicos.
During cocoa processing, a large amount of residual biomass is generated from cocoa pod husks, mucilage exudate, and seed husks. Lack of treatments for its recovery causes serious sustainability problems and means losing products with high commercial and technological potentials. This chapter aims to characterize not only the chemical composition of the residual cocoa biomass but also the different strategies that exist for its recovery. The results indicate that the three above components are a source of essential nutrients rich in valuable compounds (polyphenols, organic acids, methylxanthines, etc.). Based on this composition, valuation strategies applied to different fields, such as the food industry, human health, cosmetics, and bioremediation, are proposed for each one. These advances would help improve some socio-economical and environmental indicators and promote the sustainability of the world’s cocoa production chain.KeywordsResidual biomassPod husksMucilage exudateBean shellsBioactive compoundsRecoveryBiotransformation
The presence of bioactive compounds in winery waste streams represents a great opportunity to revalue these effluents that constitute a challenging environmental and economic problem. The main objective of this research is to develop an efficient and environmentally friendly liquid-liquid extraction process for the recovery of phenolic antioxidants from winery wastewater. Two bio-based solvents, 2-methyltetrahydrofuran (2-MeTHF) and cyclopentyl methyl ether (CPME), were evaluated as potential extractants along with ethyl acetate (EA) as benchmark organic solvent. Extraction efficiencies were maximized by testing several operation factors such as stirring time, solvent to feed ratio, concentration and alcohol effect. Subsequently, the extracted phenolic compounds were quantified by spectrophotometric (using the Folin-Ciocalteu assay, the flavonoid-aluminum chloride complexation assay and the DPPH free radical assay) and chromatographic (HPLC-DAD) methods. Overall, 2-MeTHF showed the highest extraction efficiency of target antioxidants, yielding up to 96.46% for gallic acid, 87.44% for protocatechuic acid, 80.82% for 4-hydroxybenzoic acid, 92.24% for caffeic acid, 75.18% for vanillic acid and 38.19% for syringic acid. In the interest of full sustainability, the isolation of the phenolic compounds as a solid fraction from the extraction solvent was efficiently accomplished, while the recyclability of 2-MeTHF was successfully demonstrated.
Cocoa beans are produced through on-farm processing where residual biomass is discarded, including cocoa pod husks (CPH), cocoa bean shells and cocoa sweatings. CPH represents about 80% of these residues that are generated during the initial cocoa bean processing steps and their disposal occupies large areas, causing social and environmental concerns. In the last decades, the lignocellulosic composition of CPH has attracted the attention of the scientific and productive sector. Recently, some studies have reported the use of CPH in the production of medium to high value-added molecules, with potential applications in food and feed, agriculture, bioenergy, and other segments. This review presents biotechnological approaches and processes for the exploitation of CPH, including pre-treatment methods for the production of different biomolecules. Great perspectives and innovations were found concerning CPH exploitation and valorisation, but still more efforts are needed to valorise this potential feedstock and give support to producers in-development countries.
Agri-processing industries produce enormous quantities of waste, causing environmental deterioration and degradation. The by-products from these industries, such as pomace from juice production, typically require disposal, however, they may be a valuable source of phytochemical compounds. These compounds can exhibit bioactive properties which can be further exploited as natural pigments and antioxidants for use as functional food ingredients and nutraceuticals. Conventional organic solvents for the extraction of natural compounds are toxic and hazardous, thus alternatives that are safer to handle and more environmentally friendly are sought. Natural deep eutectic solvents (NADES) have attracted much attention recently for their favorable solvent properties and benign composition consisting of naturally occurring compounds that are commonly involved in biological processes. In this chapter we discuss the extraction of natural pigments and antioxidants from fruit and vegetable processing by-products using NADES as an innovative, sustainable approach.
In this chapter, the main approach is focusing on the biorefinery of the different
structural layers of coffee waste, rather than selecting a main type of waste. Through this attempt, a circular economy with financial and environmental impacts can be achieved with implications for the coffee industry at different levels. Therefore the use of coffee waste is based on its promising chemical composition, as described in the next section, which can contribute to a sustainable development by means of obtaining high value-added products, which are explored in this chapter.
In the last decade, natural deep eutectic solvents (NADESs) have gained more and more attention due to their green, convenient preparation, low toxicity and biodegradability. It is widely used in various fields, especially in the extraction of active components from plants, formed by the combination of hydrogen bond donors (HBDs) and hydrogen bond acceptors (HBAs) at a certain condition. In this article, six preparation methods of NADESs were summarized and the interactions that occur in the eutectic behavior of NADES including hydrogen bonding, electrostatic interaction and van der Waals force were also reviewed. What is more, its significant extraction capacity on flavonoids, phenols, alkaloids and plant pigments endows its extensive applications in the extraction of active components from medicinal plants. Extraction factors including solvents properties (viscosity, carbon chain length, number of hydroxyl groups), extraction condition (water content, extraction temperature, extraction time, solid-liquid ratio), extraction method and recycling method were discussed. In addition, NADESs can also be combined with other technologies, like molecular imprinting, monolithic column, to achieve efficient and specific extraction of active ingredients. Further systematic studies on the biodegradability and biotoxicity are put forward to be urgent.
The global cocoa and chocolate market is projected to reach EUR 169 billion by 2026 due to factors such as the growth of confectionery products in Asian countries and increased demand for premium cocoa-based products. In addition, there is an increasing demand for products with high cocoa content and organic chocolates. International commodity price fluctuations and the COVID-19 pandemic have had negative impact on global market prices also influencing the efficiency of circular economy. Therefore, cocoa production chain faces the challenge of finding sustainable ways to increase production while meeting the demands of modern society. Innovative developments in this area include adding value to residues, which account for approximately 80% of the fruit. Cocoa honey is a translucent juice produced during the cocoa fermentation process, with chemical and sensory characteristics similar to cocoa pulp. This juice has high contents of pectin, minerals, and fructose and technological potential to develop new products is foreseen. Its sweet taste, for instance, can be exploited in food preparations as a natural substitute for refined sugar. This review aimed to elucidate the nutritional, technological, and economic importance of the use of this edible underutilized by-product through innovative applications in the food and beverage industry.
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Introduction:
In the present study, ternary deep eutectic solvent-based ultrasound-assisted extraction was developed for the efficient extraction of plantamajoside, acteoside, quercetin and kaempferol from Plantago asiatica L.
Methodology:
Six kinds of choline chloride-based ternary deep eutectic solvents (TDESs) were prepared as potential extraction solutions. In order to obtain optimal extraction efficiency, a series of extraction conditions were investigated by single-factor test and orthogonal test.
Results:
The extraction efficiency of choline chloride/lactic acid/ethylene glycol (ChCl-LA-EG) was much higher than that of other TDESs. ChCl-LA-EG-11 synthesised with choline chloride, lactic acid and ethylene glycol (1:4:2) was considered to have a higher extraction efficiency. The optimal ultrasound-assisted extraction conditions were as follows: water content in ChCl-LA-EG-11, 50%; extraction temperature, 70°C; ratio of solid/liquid, 20 mg/mL; ultrasonic power, 60 W; extraction time, 35 min; pH of the solution, 8. Under the optimal extraction conditions, the extraction efficiencies of plantamajoside, acteoside, quercetin and kaempferol were 3.83 ± 0.41, 4.23 ± 0.45, 0.56 ± 0.15 and 0.19 ± 0.08 mg/g, respectively. The extraction efficiency of the total target components was 9.21 ± 0.63 mg/g, which was much higher than that of conventional solvents (water, methanol, ethanol, 50% methanol, 50% ethanol). The target components were isolated efficiently from the TDES solution by an AB-8 macroporous resin column with a recovery rate of 95.6%.
Conclusion:
This study demonstrated that TDESs possessed excellent physical and chemical properties and had enormous potential for active component extraction of traditional Chinese medicinal materials.
O mel de cacau é um subproduto da produção de cacau, cujo volume vem aumentando com o crescimento da indústria de chocolates e derivados. Este líquido produzido naturalmente durante a pós-colheita do cacau tem sabor agridoce e cor clara, possui compostos bioativos, açúcares, vitamina C e fibras dietéticas de importância para a indústria de alimentos. Sua aplicação industrial ainda requer estudos aprofundados e desenvolvimento tecnológico, porém, a literatura já aponta pesquisas para desenvolvimento de novos produtos contendo mel de cacau como sorvetes, geleias mistas, vinagres e bebidas alcoólicas. Atualmente o aproveitamento do mel de cacau ocorre de forma tímida, muitas vezes artesanal, limitada às propriedades produtoras de cacau devido a restrições para seu uso industrial e questões como sua conservação, que hoje em dia ocorre basicamente pelo processo de congelamento. Com os atuais esforços para fortalecimento da bioeconomia e de exploração sustentável das cadeias produtivas, há uma grande necessidade de desenvolvimento de produtos a partir de mel de cacau, de forma a evitar seu descarte e agregar renda para os produtores. Esta revisão descreve a obtenção, a composição físico-química, o potencial bioativo e tecnológico do mel de cacau, dentro da cadeia de beneficiamento do cacau.
Although coffee is one of the most valuable and widely traded agricultural commodity in the world (US$83 billion in 2017 revenue), little information exists in the scientific literature regarding coffee bean postharvest processing. In particular, sustainability analyses require information on the coffee bean mass and property changes during processing, from harvest to final consumption. In this study, a detailed analysis of the washed or wet-processed method for coffee postharvest processing is provided. Mass flow data were collected through site visits, surveys, laboratory measurements, and interviews with coffee wet and dry mill operators in several countries throughout Central America and Mexico, as well as roasters and cafés in the United States, to establish representative mass flow rates and process flow diagrams from harvest to cup. Results indicate that 100 kg of harvested coffee cherries will on average yield 2.6 kg of mass consumed by humans as exported coffee, equivalent to approximately 839 metric cups (250 ml) of drip brew coffee or 897 metric shots (30 ml) of espresso. The remaining 97.4 kg provide opportunities for development of alternative products, and other economic uses. Importantly, the data suggests that more mass is lost during depulping in practice than previously indicated by laboratory measurements. This study provides a foundation for further investigations in the fields of equipment improvement, byproduct utilization, and environmental and economic sustainability of the coffee processing and distribution chain.
The ever-growing cocoa-product market has driven the cocoa industry to massive levels of production, thus causing excessive waste and by-product generation. Cocoa bean shells (CBS) and pod husks (CPH) are the main cocoa-industry by-products that possess substantial amounts of high added-value compounds. Polyphenols may be the most interesting compounds because of their widely known beneficial effects on human health. Over last decade, both science and industry have focused on finding new cost-effective technologies for phytochemical recovery that are able to lower extraction times, energy consumption and environmental impact. Ultrasound, microwave, pulsed electric field, and subcritical and supercritical fluid are some of these technologies. This review summarizes successful CBS and CPH polyphenol extraction processes that make use of the above-mentioned emerging methods. Moreover, the integration of novel business paradigms, in particular the circular economy and industry 4.0, can help sustainability to be achieved in the cocoa industry.
Industrial relevance text
Industrial cocoa by-products have become a massive burden since their inadequate disposal leads to a series of environmental issues. Value-added compounds recovery from CBS and CPH by means of enabling technologies assistance can lead to significant economic and environmental advantages. This approach, coherent with circular economy paradigm, can be integrated with a design of Industry 4.0 driving the development of new products and businesses.
The current study encompasses the development of a combined pretreatment strategy using deep eutectic solvent (DES) i.e. choline chloride (ChCl)/glycerol and ultrasonic waves for the digestibility of sugarcane bagasse (SCB). Pretreated biomass was saccharified by an enzyme cocktail produced in house from a novel fungus Aspergillus assiutensis VS34. Combined ChCl/glycerol and ultrasound pretreatment yielded higher sugars (276.8 mg/g biomass) than either of the individual pretreatments i.e. ChCl/glycerol (235.3 mg/g biomass) or ultrasound (174.5 mg/g biomass). Optimization of pretreatment process variables (biomass loading, sonication amplitude and pretreatment time) by Design of Experiment enhanced sugar yield by 1.12-fold. Sugar hydrolysate obtained was fermented by dual yeast cultures i.e. Saccharomyces cerevisiae and Pichia stipitis to get an ethanol yield of 142.09 mg/g biomass. To understand the molecular mechanism of combined DES/ultrasound pretreatment which led to eased hydrolysis, and enhanced sugar yield, the pretreated biomass was studied by SEM, FT-IR, XRD and ¹H NMR analysis for various structural aberrations that made the biomass more amenable to enzymatic hydrolysis. Insights of underlying functional mechanisms of pretreatment may help in developing new/novel designer pretreatment approaches for proficient biomass conversion.
Levodopa (L-dopa) is an amino acid precursor of the catecholamines dopamine, norepinephrine and epinephrine, which can be used in the treatment of Parkinson's disease. Levodopa is present in several vegetable sources, such as Mucuna pruriens seeds. However, the extraction of levodopa from vegetable matrices is usually carried out with volatile organic solvents (methanol, hexane and chloroform). In this work we demonstrate that aqueous solutions of eutectic solvents (ES) can be used as alternative solvents for the extraction of levodopa. Eutectic solvents based on carboxylic acids or polyols combined with cholinium chloride ([Ch]Cl) were studied. Experimental conditions such as temperature, solid-liquid (solvent-biomass) ratio and ES concentration in aqueous solution were optimized by a response surface methodology, with the aim of maximizing the levodopa extraction yield. Extraction yields up to 9.9 ± 1.0 wt.% (levodopa per dry weight of Mucuna pruriens seeds) were obtained at a temperature of 56 °C, solid-liquid ratio of 1:7 and ES concentration close to 35 wt.%. The recovery of levodopa from the ES aqueous solutions was achieved by a subsequent solid-phase extraction step, allowing to recover 87% of the extracted levodopa with high purity. This step further allowed the solvent recovery and reuse, demonstrating that the solvent can be reused at least three times without compromising the extraction yield for levodopa. This work shows the remarkable capacity of ES aqueous solutions to extract the value-added compound levodopa from biomass and the possibility of applying reusable solvents, paving the way for their use as alternative solvents to extract bioactive compounds from natural sources.
The growing social concern regarding the use of more environmentally friendly processes is compelling the search of more biocompatible solvents able to overcome the drawbacks associated to the conventional ones. Thus, in this work, a Deep Eutectic Solvent (cholinium chloride:urea) was demonstrated to act as salting out agent in aqueous solutions of a model non-ionic surfactant (Triton X-100). Thus, the immiscibility region was thoroughly mapped in a range of temperatures, from T 293.15 to 323.15 K. The experimental data for each solubility curves were fitted to different empirical models based on exponential and polynomial equations. Furthermore, Othmer-Tobias and Bancroft equations have been used to correlate the tie-line data, and to provide a clearer picture of the role of these solvents as phase promoters in surfactants solutions. Finally, the extraction capacity of this system at 303.15 K was assessed for removing textiles dyes from aqueous streams, in order to demonstrate the suitability of DESs to be used as adjuvants in the remediation of industrial effluents.
Chemical reactions and many of the procedures of separation and purification employed in industry, research or chemistry teaching utilize solvents massively. In the last decades, with the birth of Green Chemistry, concerns about the employment of solvents and the effects on human health, as well as its environmental impacts and its dependence on non-renewable raw materials for manufacturing most of them, has drawn the attention of the scientific community. In this work, we review the concept of green solvent and the properties and characteristics to be considered green. Additionally, we discuss the different possible routes to prepare many solvents from biomass, as an alternative way to those methods currently applied in the petrochemical industry.
The nanostructure of a series of choline chloride-urea-water deep eutectic solvent mixtures was characterized across a wide hydration range, using neutron total scattering and empirical potential structure refinement (EPSR). Since structure is significantly altered, even at low hydration levels, reporting DES water content is important. However, DES nanostructure is retained to a remarkably high level of water (10w, ~42 wt.% H2O) because of solvophobic sequestration of water into nanostructured domains around cholinium cations. At 51 wt. % / 83 mol % H2O this segregation becomes unfavorable, and the DES structure is disrupted, instead dominated by water-water and DES-water interactions. At and above this hydration level, the DES-water mixture is best described as an aqueous solution of DES components.
The green chemistry era has pushed the scientific community to investigate and implement new solvents in the phenolic compounds (PC) extraction, as alternative to the organic solvents which are toxic and may be dangerous. Recently, Deep Eutectic Solvents (DES) have been applied as extraction solvents of PC. They have the advantages to be biodegradable, easy to handle with very low toxicity. Nevertheless, the extraction process is affected by several factors: affinity between DES and the target compounds, the water content, the molar ratio between DES’ starting molecules, the liquid:solid ratio between the DES and sample, and the conditions and extraction method. On the other hand, the PC recovery from DES is a challenge; since they can establish a strong hydrogen bonds network. Alternatively, another possibility is to use DES as solvent extraction as well as formulation media. In this way, DES can be suitable for cosmetics, pharmaceutical, or food applications.
Several novel applications of Deep Eutectic Solvents (DESs) have emerged recently. With a growing interest in the field, there is an urge to understand formation and functioning of these solvents at molecular level, which in turn would assist in further designing of DESs. We herein performed molecular dynamics simulations on three of the commonly used type III DES, viz, reline, ethaline, and glyceline, which are mixtures of urea, ethylene glycol, and glycerol with choline chloride at eutectic composition. Our results explain the role of inter-molecular and intra-molecular hydrogen bonding and energies on formation of these DESs. Furthermore, the ability of these DESs to be altered in a desired way through a simple addition of water makes it versatile solution for several other applications. Hence, simulations are also performed on the aqueous DES solutions, which reveal the effect of water on intermolecular network of interaction existing within these DESs.
Several abundant agri-food wastes, including lemon peels, olive leaves, onion solid wastes, red grape pomace, spent filter coffee and wheat bran, were used to test the efficiency of some novel glycerol-based natural eutectic mixtures to extract polyphenolic compounds. Extractions were performed under specified ultrasonication conditions and the eutectic mixtures, tested as 90 % (v/v) aqueous solutions, were glycerol:choline chloride, glycerol:sodium acetate and glycerol:sodium–potassium tartrate:water, with corresponding molar ratios of 3:1, 3:1 and 5:1:4. The latter two mixtures are reported for the first time. Water and 60 % (v/v) aqueous ethanol were also used as control solvents. The results obtained evidenced that glycerol:choline chloride exhibited high efficiency, which was comparable or even surpassed that of aqueous ethanol, but in some instances the same was observed for glycerol:sodium acetate too. In general, glycerol:sodium–potassium tartrate:water displayed lower efficiency in extracting polyphenols. The data also suggested that extracts with high polyphenol concentration may also possess higher antiradical activity and reducing power. The findings of this study were interpreted on the ground of assumptions regarding the polarity of the eutectic mixtures tested.
Coffee pulp contains natural antioxidants like hydroxycinnamic acids, most of which are covalently linked to the cell wall. These compounds can be released by fermentation or enzymatic processes. In this study, the antioxidant properties of fermented and nonfermented
coffee pulp have been evaluated. Coffee pulp was fermented by solid-state fermentation using the fungus Aspergillus tamarii. Fermented and nonfermented samples of coffee pulp were extracted with aqueous methanol followed by alkaline hydrolysis. In both cases, the total polyphenol concentration was quantified by Folin-Ciocalteu method, then hydroxycinnamic acids were concentrated using ethyl acetate and quantified by HPLC. The antioxidant properties of samples were determined by radical monocation of 2,2’-azinobis-(
3-ethylbenzothiazoline-6-sulphonic acid) [ABTS]·+: the antioxidant activity was determined by kinetic parameters known as ED50, tED50 and antiradical efficiency (AE). Fermented extracts containing free hydroxycinnamic acids showed better antiradical activity against [ABTS]·+ than the other nonfermented ones. There were no significant differences in the total content of polyphenols in fermented and nonfermented coffee pulp, but the content of total hydroxycinnamic acids was higher in the nonfermented coffee pulp extracts (47.1 g/kg) than in the fermented coffee pulp (30.9 g/kg). Nevertheless, the fermentation process increased the fraction of free hydroxycinnamic acids (47 %) and consequently decreased those covalently linked to the cell wall. The results of the antioxidant
activity assays could be explained by the presence of free hydroxycinnamic acids. Fermented coffee pulp assays showed that free hydroxycinnamic acids were metabolised by A. tamarii. This study shows the potential of using coffee pulp as a natural source of antioxidants.
Recently, furfural, “the sleeping beauty bio-renewable chemical” has gained a renewed attention as a potential chemical for the production of biofuels and biochemicals. Furfural is the most commonly produced industrial chemical because its production is very flexible. It is one of the top value-added chemicals that can be produced from biomass. Furfural and its derivatives have been extensively used in plastics, pharmaceutical and agrochemical industries. Furfural is a natural precursor to a range of furan-based chemicals and solvents such as dihydropyran, methyltetrahydrofuran, tetrahydrofuran, methylfuranfurfuryl alcohol, tetrahydrofurfuryl alcohol and furoic acid. Furfural and its derivatives have been widely applied as fungicides and nematicides, transportation fuels, gasoline additives, lubricants, resins, decolorizing agents, jet fuel blend stocks, drugs, insecticides, bio-plastics, flavor enhancers for food and drinks, rapid all-weather repair system for bomb-damaged runways and pot holes and also for wood modification and book preservation.
The present investigation demonstrated pretreatment of lignocellulosic biomass rice straw using natural deep eutectic solvents (NADESs), and separation of high-quality lignin and holocellulose in a single step. Qualitative analysis of the NADES extract showed that the extracted lignin was of high purity (>90 %), and quantitative analysis showed that nearly 60 ± 5 % (w/w) of total lignin was separated from the lignocellulosic biomass. Addition of 5.0 % (v/v) water during pretreatment significantly enhanced the total lignin extraction, and nearly 22 ± 3 % more lignin was released from the residual biomass into the NADES extract. X-ray diffraction studies of the untreated and pretreated rice straw biomass showed that the crystallinity index ratio was marginally decreased from 46.4 to 44.3 %, indicating subtle structural alterations in the crystalline and amorphous regions of the cellulosic fractions. Thermogravimetric analysis of the pretreated biomass residue revealed a slightly higher T dcp (295 °C) compared to the T dcp (285 °C) of untreated biomass. Among the tested NADES reagents, lactic acid/choline chloride at molar ratio of 5:1 extracted maximum lignin of 68 ± 4 mg g(-1) from the rice straw biomass, and subsequent enzymatic hydrolysis of the residual holocellulose enriched biomass showed maximum reducing sugars of 333 ± 11 mg g(-1) with a saccharification efficiency of 36.0 ± 3.2 % in 24 h at 10 % solids loading.
This study presents a review of the Folin-Ciocalteu (F-C) assay for total phenolic content (TPC) determinations and describes different approaches to improve its specificity. Phenolics are regarded as the molecules with the highest potential to neutralize free radicals. Therefore, their quantification is a common practice in different areas of food research. However, when determining TPC in plant food extracts, the presence of reducing interferants [ascorbic acid (AA)] produces inaccurate estimations of TPC values. Different methodologies have been proposed to improve the specificity of the F-C assay. These methodologies include: (i) the use of solid phase extraction (SPE) cartridges to separate interferants from phenolics; (ii) the calculation of a corrected TPC value based on the AA reducing activity present in the extract; and (iii) the pre-treatment of extracts with oxidative agents prior to TPC quantification. These methods are described in detail in the present study. Likewise, their advantages and disadvantages are discussed based on new experimental data. A simple modification of the F-C assay procedure is proposed to quantify both the TPC value and the AA reducing activity in plant food extracts. Values obtained by the modified F-C assay can be used to estimate a corrected TPC value.
Green and efficient extraction of natural products from biomass is considered an important field in the pharmaceutical and biochemical industries. Recently, deep eutectic solvents (DESs) have been growing in interest as sustainable and safe solvents. In this study, we aimed to provide a practical example using a popular traditional Chinese medicine, Flos sophorae, showcasing the tuneability of DESs as designer solvents to selectively and efficiently extract bioactive compounds from biomass. As a result, a solvent called PG-1 that was tailor-made from a 2:5 mixture of L-proline and glycerol using freeze-drying method, was more effective than methanol for extraction of quercetin, kaempferol, and isorhamnetin glycosides from Flos sophorae. With PG-1-based ultrasound-assisted extraction (UAE), operational conditions including the DES content in the extractant, extractant-to-sample solid ratio, and ultrasound irradiation time for UAE were statistically optimized using a central composite design combined with response surface methodology. The resulting extraction method in which 50 mg of sample powder was extracted by UAE for 45 min using 1.00 mL of aqueous solution containing 90% w/w PG-1 was found to be a greener and more efficient process than common extraction methods such as methanol-based UAE and heat reflux extraction that are generally environmentally harmful. Based on the antioxidant activity measured by DPPH assay, the tailor-made extractant exhibited additive activity arising from its component, L-proline. Recovery of extracted flavonoids from the DES, which was assessed from rutin, since it is the major flavonoid extracted, was 75% with the use of water as an anti-solvent, and could reach as high as 92% with the simple application of C18 solid phase extraction (SPE). In comparison, the recovery efficiency of the anti-solvent method was significantly reduced for the flavonoid glycosides from the real Flos sophorae extracts, while the efficiency of the SPE method was reasonably high (81-87%). The present study suggests that DESs are truly designer solvents that can be used as sustainable and safe extraction media for pharmaceutical and biochemical applications.
The research into ionic liquids (IL) has escalated in the last two decades, ever since the potential for new chemical technologies was realized. In the period covered by this review, approximately 6000 journal articles have been published on the topic. Compared to classical ILs, the research into DESs is comparatively in its infancy, with the first paper on the subject only published in 2001. DESs contain large, nonsymmetric ions that have low lattice energy and hence low melting points. They are usually obtained by the complexation of a quaternary ammonium salt with a metal salt or hydrogen bond donor (HBD). A majority of ionic liquids which are fluid at ambient temperatures are formed using an organic cation, generally based around ammonium, phosphonium, and sulfonium moieties. The second generation of ionic liquids are those that are entirely composed of discrete ions, rather than the eutectic mixture of complex ions seen in the first generation ionic liquids.
Green technology actively seeks new solvents to replace common organic solvents that present inherent toxicity and have high volatility, leading to evaporation of volatile organic compounds to the atmosphere. Over the past two decades, ionic liquids (ILs) have gained enormous attention from the scientific community, and the number of reported articles in the literature has grown exponentially. Nevertheless, IL “greenness” is often challenged, mainly due to their poor biodegradability, biocompatibility, and sustainability. An alternative to ILs are deep eutectic solvents (DES). Deep eutectic solvents are defined as a mixture of two or more components, which may be solid or liquid and that at a particular composition present a high melting point depression becoming liquids at room temperature. When the compounds that constitute the DES are primary metabolites, namely, aminoacids, organic acids, sugars, or choline derivatives, the DES are so called natural deep eutectic solvents (NADES). NADES fully represent green chemistry principles. Can natural deep eutectic solvents be foreseen as the next generation solvents and can a similar path to ionic liquids be outlined? The current state of the art concerning the advances made on these solvents in the past few years is reviewed in this paper, which is more than an overview on the different applications for which they have been suggested, particularly, biocatalysis, electrochemistry, and extraction of new data. Citotoxicity of different NADES was evaluated and compared to conventional imidazolium-based ionic liquids, and hints at the extraction of phenolic compounds from green coffee beans and on the foaming effect of NADES are revealed. Future perspectives on the major directions toward which the research on NADES is envisaged are here discussed, and these comprised undoubtedly a wide range of chemically related subjects.
Several methods have been described for the determination of phenolic compounds in animal and plant products using the Folin-Ciocalteu (FC) assay. Most of these methods describe the use of this reagent and sodium carbonate in spectrophotometric methods. The macro FC assay was compared with two micro FC assays carried out on a microplate reader. Excellent correlation was obtained among the three assays with a molar extinction coefficient of 5.228±0.187x103 M−1 cm−1. The micro assay may serve as a high throughput method for the rapid determination of polyphenols in various samples.
This work reports the first lipase-catalyzed reactions between substrates of different polarities using deep eutectic solvents as a medium. The model reaction consisted of a lipophilization process based on the alcoholysis of phenolic esters using immobilized Candida antarctica lipase B as a biocatalyst. Results showed that water could dramatically improve the lipase activity and change the reactivity of phenolic substrates. Indeed, very low conversions (<2%) were observed in pure DES, whereas in DES–water binary mixtures, quantitative conversions were achieved. After investigating the role of various parameters, such as the substrate concentration and ratio, pH or thermodynamic activity of water, the effect of the presence of water in pure DES based on urea or glycerol was discussed. In this paper, we propose new perspectives for the enzymatic modification of polar substrates using this novel generation of green, inexpensive and easy-to-handle solvents.
Cocoa Pod Husk (CPH) is a major by-product from the cocoa industry in Ghana. Using CPH as a lowcost unconventional feedstuff is hampered by its poor nutrient composition due to high level of nonstarch polysaccharides including cellulose, pectin and hemicellulose, which are indigestible in monogastric livestock such as poultry. An in vitro enzyme treatment study was conducted to test the effect of various combinations of selected exogenous fibrolytic enzymes on the digestibility of CPH feedstuff. Concentrations of 0.8, 0.6 and 0.8% w/w respectively for Pentopan®MonoBG, Viscozyme®L and Pectinex®5XL were observed as appropriate levels for supplementing CPH feedstuff. Among the enzyme combinations tested, the Pentopan®MonoBG + Viscozyme®L, Viscozyme®L + Pectinex®5XL and Pentopan®MonoBG + Viscozyme®L + Pectinex®5XL formulae were most effective in maximising sugar release from CPH feedstuff by 42 - 53% increase with a corresponding reduction (7 - 14%) in crude fibre and non-starch polysaccharide fractions (P < 0.05). The present results suggest that supplementation with multi-enzymes or blends of exogenous NSP-degrading enzymes may enhance the capacity of poultry to efficiently digest and utilise dietary CPH.
Developing green solvents with low toxicity and cost is an important issue for the biochemical industry. Synthetic ionic liquids and deep eutectic solvents have received considerable attention due to their negligible volatility at room temperature, high solubilization ability, and tunable selectivity. However, the potential toxicity of the synthetic ionic liquids and the solid state at room temperature of most deep eutectic solvents hamper their application as extraction solvents. In this study, a wide range of recently discovered natural ionic liquids and deep eutectic solvents (NADES) composed of natural compounds were investigated for the extraction of phenolic compounds of diverse polarity. Safflower was selected as a case study because its aromatic pigments cover a wide range of polarities. Many advantageous features of NADES (such as their sustainability, biodegradability combined with acceptable pharmaceutical toxicity profiles, and their high solubilization power of both polar and non-polar compounds) suggest their potential as green solvents for extraction. Experiments with different NADES and multivariate data analysis demonstrated that the extractability of both polar and less polar metabolites was greater with NADES than conventional solvents. The water content in NADES proved to have the biggest effect on the yield of phenolic compounds. Most major phenolic compounds were recovered from NADES with a yield between 75%-97%. This study reveals the potential of NADES for applications involving the extraction of bioactive compounds from natural sources.
Developing new green solvents is one of the key subjects in Green Chemistry. Ionic liquids (ILs) and deep eutectic solvents, thus, have been paid great attention to replace current harsh organic solvents and have been applied to many chemical processing such as extraction and synthesis. However, current ionic liquids and deep eutectic solvents have still limitations to be applied to a real chemical industry due to toxicity against human and environment and high cost of ILs and solid state of most deep eutectic solvents at room temperature. Recently we discovered that many plant abundant primary metabolites changed their state from solid to liquid when they were mixed in proper ratio. This finding made us hypothesize that natural deep eutectic solvents (NADES) play a role as alternative media to water in living organisms and tested a wide range of natural products, which resulted in discovery of over 100 NADES from nature. In order to prove deep eutectic feature the interaction between the molecules was investigated by nuclear magnetic resonance spectroscopy. All the tested NADES show clear hydrogen bonding between components. As next step physical properties of NADES such as water activity, density, viscosity, polarity and thermal properties were measured as well as the effect of water on the physical properties. In the last stage the novel NADES were applied to the solubilization of wide range of biomolecules such as non-water soluble bioactive natural products, gluten, starch, and DNA. In most cases the solubility of the biomolecules evaluated in this study was greatly higher than water. Based on the results the novel NADES may be expected as potential green solvents at room temperature in diverse fields of chemistry.
Ultrasound assisted extraction (UAE) process enhancement for food and allied industries are reported in this review. This includes herbal, oil, protein and bioactives from plant and animal materials (e.g. polyphenolics, anthocyanins, aromatic compounds, polysaccharides and functional compounds) with increased yield of extracted components, increased rate of extraction, achieving reduction in extraction time and higher processing throughput. Ultrasound can enhance existing extraction processes and enable new commercial extraction opportunities and processes. New UAE processing approaches have been proposed, including, (a) the potential for modification of plant cell material to provide improved bioavailability of micro-nutrients while retaining the natural-like quality, (b) simultaneous extraction and encapsulation, (c) quenching of the radical sonochemistry especially in aqueous systems to avoid degradation of bioactives and (d) potential use of the radical sonochemistry to achieve targeted hydroxylation of polyphenolics and carotenoids to increase bioactivity.
Within the framework of green chemistry, solvents occupy a strategic place. To be qualified as a green medium, these solvents have to meet different criteria such as availability, non-toxicity, biodegradability, recyclability, flammability, and low price among others. Up to now, the number of available green solvents are rather limited. Here we wish to discuss a new family of ionic fluids, so-called Deep Eutectic Solvents (DES), that are now rapidly emerging in the current literature. A DES is a fluid generally composed of two or three cheap and safe components that are capable of self-association, often through hydrogen bond interactions, to form a eutectic mixture with a melting point lower than that of each individual component. DESs are generally liquid at temperatures lower than 100 °C. These DESs exhibit similar physico-chemical properties to the traditionally used ionic liquids, while being much cheaper and environmentally friendlier. Owing to these remarkable advantages, DESs are now of growing interest in many fields of research. In this review, we report the major contributions of DESs in catalysis, organic synthesis, dissolution and extraction processes, electrochemistry and material chemistry. All works discussed in this review aim at demonstrating that DESs not only allow the design of eco-efficient processes but also open a straightforward access to new chemicals and materials.
Recently, deep eutectic solvents (DESs) have been recognized as a novel class of sustainable solvents to replace common organic solvents. In this study, a highly and efficient extraction technique for determination of four bioactive flavonoids from Pollen Typhae using a combination of ultrasound-assisted extraction and natural deep eutectic solvents (NADESs) was developed. A series of DESs containing various hydrogen bond acceptors combined with different hydrogen bond donors were synthesized and screened for high extraction efficiencies based on the flavonoids extraction yields. The extraction conditions including composition of DES, water content in DES, liquid-solid ratio, and extraction time were statistically optimized by single-factor experiment. As a result, DES composed of choline chloride and 1,2-propanediol (ChPri) at 1:4 M ratio, 30% of aqueous solution, 50:1 mg mL-1 for solid-liquid ratio, and 35 min for extraction time were selected as the most effective process for extraction of flavonoids in Pollen Typhae. Under the optimal conditions, the target compounds recoveries were in the range of 86.87%-98.89%. Meanwhile, DESs showed greater extraction efficiency for extraction of quercetin, naringenin, kaempferol and isorhamnetin from Pollen Typhae comparing with conventional solvents such as methanol and 75% of aqueous ethanol. Comparing DESs to the conventional organic solvents, in addition to their reduced environmental impacts, they proved to provide higher extraction efficiency for flavonoids, and therefore have a great potential as possible alternatives to those organic solvents in extraction of Chinese herbal medicines.
The scientific community, experts in technology and marketing have been seeking cost-competitive and green solvents with good dissolving capacity for the valorisation of biomass and biowaste. Along with traditional solvents and techniques, deep eutectic solvents (DESs) and their bio-analogues, natural deep eutectic solvents (NADESs) are currently emerging as a new class of promising liquid media. In this review, a comprehensive summary of recent contribution of DESs to the processing and valorisation of various kinds of plant and animal based biomass and biowaste is provided. In the field of food industry based and agro-forest waste valorisation, through treatment of the waste, by-products, and natural materials by DESs, several types of compounds, such as flavonoids and other plant phenolics, phenolic acids, stilbenes, tannins, lignans, and lignin were obtained. Extraction of algae by DESs led to isolation mainly of proteins, carbohydrates, lipids and nucleic acids. Vegetable oils, spent oils, residues and by-products of their processing are a rich source of phenolic compounds such as phenolic acids and phenolic alcohols, secoiridoid derivatives (aglycone and ligstroside), lignans (pino and acetoxypinoresinol), flavones (luteolin and apigein), tocopherols and tocotrienols. Dietary fibre serves as a source of lignin, pectic substances, gums, resistant starch, inulin, as well as non-carbohydrate components, e.g., polyphenols, waxes, saponins, cutin, phytates, resistant proteins. Valorisation of wastes originated from animal processing by DESs means obtaining high-value chemicals including amino acids, proteins, bioactive peptides, collagen peptides, albumin etc. Through the valorisation of the mentioned waste types value-added products with potential applications in the pharmaceutical, food and cosmetic industries are produced. The paper gathered data on the used DESs, treated substances and obtained products, together with treatment conditions and the products yields. The evaluation of the state-of-the-art in the field of biowaste valorisation using DESs and NADESs led to conclusions and indication of future prospects and predicted development in this field.
Extraction of polyphenolic compounds from orange peel (OP) via solid-liquid extraction (SLE) using deep eutectic solvents (DES) was investigated in this work as a means to develop sustainable separation processes to recover natural antioxidants from food waste biomass. In particular, choline chloride-based DES paired with glycerol and ethylene glycol were explored as potential extractants to evaluate the effect of the solvent structure (i.e. number of hydroxyl groups and hydrogen bond acceptor/donor ratio) on the polyphenol extraction efficiency. Afterwards, the effect of different operating parameters (i.e. solvent concentration, temperature, time and solid/liquid ratio) were further evaluated to determine the optimal extraction conditions for polyphenols recovery in terms of total phenolic content (TPC) and antioxidant activity based on DPPH radical scavenging method. Under optimum conditions (DES 10 wt.% water, temperature of 333.15 K, 1:10 solid/liquid ratio and extraction time of 100 min), choline chloride-based DES outperformed the benchmark solvent (aqueous (aq.) ethanol 30 wt.% water) for the extraction of polyphenolic compounds from OP, with [Ch]Cl:EG 1:4 providing the highest TPC (3.61 mg gallic acid equivalent per gram of orange peel (GAE/g OP) and antioxidant potential (30.6 µg/ml). Although ethylene glycol (EG) has provided the highest TPC (5.84 mg GAE/g OP), DES have proved more selective towards target polyphenolic compounds. Additionally, Scanning Electron Microscopy (SEM) was performed to illustrate the structural modifications occurred on the biomass before and after the extraction process, supporting DES as efficient solvents for cell wall dissolution. Lastly, characterization and quantification of individual polyphenolic profiles in the extracts were completed via high performance liquid chromatography (HPLC), displaying ferulic acid as the most abundant compound followed by ρ-coumaric acid and gallic acid.
Natural deep eutectic solvents (NADESs) have been postulated as alternative green solvents for the isolation of valuable bioactive compounds from Lippia citriodora. Thus, 11 different NADESs, based on choline chloride (ChCl) as the hydrogen bond acceptor in combination with different hydrogen bond donors (organic acids, polyalcohols, sugars, and urea) were tested. According to the results obtained, ChCl-lactic acid exhibited the highest extraction yield for iridoids, 7.25 mg g⁻¹, phenylpropanoids, 17.23 mg g⁻¹, and flavonoids, 9.02 mg g⁻¹ being significantly greater than phenylpropanoid and flavonoid yields, 15.63 and 5.43 mg g⁻¹ respectively, extracted with methanol as conventional solvent. Subsequently, in order to optimise the most influential microwave assisted extraction (MAE) parameters, a Box-Behnken design paired with a response surface methodology were implemented. Temperature and water content showed a strong effect on the extraction of polyphenol sub-classes, while the effect of irradiation time was less noticeable on extraction yields. Temperature of 63.68 °C, a water content of 32.19% and a microwave irrdiation time of 17.08 min were the optimum conditions provided by the statistical program. The use of NADESs showed potential to facilitate the design and customisation of green tailor-made solvents which have greater extraction capacity than conventional organic solvents.
Spent coffee grounds (SCGs) are viewed as a valuable resource for useful bioactive compounds, such as chlorogenic acids and flavonoids, and we suggest an eco-friendly and efficient valorization method. A series of choline chloride-based deep eutectic solvents (DESs) were tested as green extraction solvents for use with ultrasound-assisted extraction. Extraction efficiency was evaluated based on total phenolic content (TPC), total flavonoid content, total chlorogenic acids, and/or anti-oxidant activity. A binary DES named HC-6, which was composed of 1,6-hexanediol:choline chloride (molar ratio 7:1) was designed to produce the highest efficiency. Experimental conditions were screened and optimized for maximized efficiency using a two-level fractional factorial design and a central composite design, respectively. As a result, the proposed method presented significantly enhanced TPC and anti-oxidant activity. In addition, phenolic compounds could be easily recovered from extracts at high recovery yields (>90%) by adsorption chromatography.
Sustainable solvents are a topic of growing interest in both the research community and the chemical industry due to a growing awareness of the impact of solvents on pollution, energy usage, and contributions to air quality and climate change. Solvent losses represent a major portion of organic pollution, and solvent removal represents a large proportion of process energy consumption. To counter these issues, a range of greener or more sustainable solvents have been proposed and developed over the past three decades. Much of the focus has been on the environmental credentials of the solvent itself, although how a substance is deployed is as important to sustainability as what it is made from. In this Review, we consider several aspects of the most prominent sustainable organic solvents in use today, ionic liquids, deep eutectic solvents, supercritical fluids, switchable solvents, liquid polymers, and renewable solvents. We examine not only the performance of each class of solvent within the context of the reactions or extractions for which it is employed, but also give consideration to the wider context of the process and system within which the solvent is deployed. A wide range of technical, economic, and environmental factors are considered, giving a more complete picture of the current status of sustainable solvent research and development.
Is hydration the solution to the viscosity of deep eutectic solvents (DESs)? In their Communication (DOI: 10.1002/anie.201702486), K. J. Edler and co-workers determine the nanostructure of DES/water mixtures over a wide hydration range by neutron diffraction and atomistic modeling. The mixture retains the characteristics of the DES structure up to remarkably high water levels and is then converted into a state best described as a simple aqueous solution of the DES molecular components.
Cocoa shell is removed from the cocoa bean before or after the seeds are roasted; it is considered a by-product of the cocoa industry that is usually underutilized or considered waste. Some studies and patents have been developed in order to give a nobler destination to this material. Interest in cocoa shell is due to its high nutritional value owing to the presence of a variety of biocompounds, such as phenolic compounds, dietary fibers, theobromine and a lipid profile similar to that of cocoa butter, besides its chocolate color and flavor.
The disintegration of orange peel waste in deep eutectic solvents and diluted organic acids is presented in this work. The albedo and flavedo layers of the peel were studied separately, showing faster disintegration of the latter. Addition of water to the deep eutectic solvents lowered the amount of remaining solids and improved the disintegration times. These improvements are subscribed to a decrease in viscosity upon deep eutectic solvent dilution. Each of the individual deep eutectic solvent components were diluted and subjected to the same disintegration tests. The corresponding diluted organic acids showed similar orange peel disintegration performance as the tested deep eutectic solvents, whereas dilutions of the other counterparts did not show any activity. Hence, the active deep eutectic solvent components during orange peel treatment are considered to be their organic acids. Flavonoids and essential oils were released during the treatment, offering new opportunities for the development of orange peel waste valorisation routes.
Cocoa crops development presents challenges concerning the proper disposal of waste generated by this activity, and the obtaining of value-added products. Thus, the aim of this study was to obtain pectin from cocoa pod husk (Theobroma cacao L.). Infrared spectrum results showed peaks of galacturonic acid functional groups, indicating the presence of pectin in the cocoa husk. In extraction stage was carried out acid hydrolysis with citric or acetic acid at different pH (2, 2.5 and 3), 90°C temperature and 90 minutes, and was evaluated its influence on yield, methoxyl and galacturonic acid content. From the established extraction conditions, aqueous citric acid at pH 2.0 provided the highest yield and methoxyl content, 18.12% and 15.5% respectively. While the galacturonic acid content showed better results with acetic acid at pH 3 with an 83.1%. Finally, it was concluded that cocoa pod husks are suitable to obtain pectin, and a marked influence of the type of acid on response variables in the pectin extraction process was observed.
In this Minireview, the state of the art in the use of ionic liquids (ILs) and deep eutectic solvents (DESs) as alternative reaction media for biocatalytic processes and biomass conversion is presented. Initial, proof-of-concept studies, more than a decade ago, involved first-generation ILs based on dialkylimidazolium cations and non-coordinating anions, such as tetrafluoroborate and hexafluorophosphate. More recently, emphasis has switched to more environmentally acceptable second-generation ILs comprising cations, which are designed to be compatible with enzymes and, in many cases are derived from readily available, renewable resources, such as cholinium salts. Protic ionic liquids (PILs), prepared simply by mixing inexpensive amines and acids, are particularly attractive from both an environmental and economic viewpoint. DESs, prepared by mixing inexpensive salts with, preferably renewable, hydrogen-bond donors such as glycerol and amino acids, have also proved suitable reaction media for biocatalytic conversions. A broad range of enzymes can be used in ILs, PILs and DESs, for example lipases in biodiesel production. These neoteric solvents are of particular interest, however, as reaction media for biocatalytic conversions of substrates that have limited solubility in common organic solvents, such as carbohydrates, nucleosides, steroids and polysaccharides. This has culminated in the recent focus of attention on their use as (co)solvents in the pretreatment and saccharification of lignocellulose as the initial steps in the conversion of second-generation renewable biomass into biofuels and chemicals. They can similarly be used as reaction media in subsequent conversions of hexoses and pentoses into platform chemicals.
This paper reports a new method of applying Deep Eutectic Solvents (DES) for extracting lignin from woody biomass with high yield and high purity. DES mixtures prepared from Choline Chloride (ChCl) and four hydrogen-bond donors–acetic acid, lactic acid, levulinic acid and glycerol–were evaluated for treatment of hardwood (poplar) and softwood (D. fir). It was found that these DES treatments can selectively extract a significant amount of lignin from wood with high yields: 78% from poplar and 58% from D. fir. The extracted lignin has high purity (95%) with unique structural properties. We discover that DES can selectively cleave ether linkages in wood lignin and facilitate lignin removal from wood. The mechanism of DES cleavage of ether bonds between phenylpropane units was investigated. The results from this study demonstrate that DES is a promising solvent for wood delignification and the production of a new source of lignin with promising potential applications.
Deep eutectic solvents (DESs) are emerging as green and sustainable solvents for efficient extraction of bioactive compounds or drugs. This work aimed to comprehensively evaluate the potential and effectiveness of DESs for extraction of different types of natural compounds from biomass. Five Chinese herbal medicines including Berberidis Radix, Epimedii Folium, Notoginseng Radix et Rhizoma, Rhei Rhizoma et Radix, and Salviae Miltiorrhizae Radix et Rhizoma were selected to assess the efficiency of DESs on extraction of alkaloids, flavonoids, saponins, anthraquinones, and phenolic acids, respectively. Totally 43 types of choline chloride-, betaine- and L-proline-based DESs with different polarity, viscosity, composition, and solubilization abilities were tailored to test their extraction efficiency, and the operation conditions were statistically optimized using response surface methodology to produce the most efficient process. In this work, DES solvents were firstly introduced to extract alkaloids and anthraquinones. The results indicated that most prepared DESs proved to be efficient solvents for extraction of alkaloids, but lower extractability for anthraquinones. The extraction capacity of DES may be correlated with their physical-chemical properties, including H-bonding interactions, polarity, viscosity and pH. This study demonstrated that DESs were suitable green extraction solvents for selectively and efficiently extracting bioactive compounds from biomaterials.
At the coffee production sites (farms and estates), two different main methods of processing are used to obtain intermediate products that will subsequently be treated in exactly the same way to provide the coffee beans of commerce. These methods are dry processing, which produces dried cherry coffee and wet processing, which produces (dry) parchment coffee. Dry processing is generally used for robusta coffee, but is also used in Brazil for the majority of arabica coffees. Wet processing, on the other hand, is used for arabica and results in so-called mild coffee, when fermentation is included in the preparation process. Dry processing is very simple and, most important of all, is less demanding in respect of harvesting, since all the berries or cherries are dried immediately after harvest. In contrast, wet processing requires more strict control of the harvesting as unripe berries or berries that have partly dried on the tree cannot be handled by the pulping machines.
