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An Overview of the Potential Uses for Coffee Husks

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Abstract

Coffee is one of the top commodities produced and commercialized worldwide, and the processing of coffee generates significant amounts of agricultural waste, ranging from 30% to 50% the weight of the total coffee produced, depending on the type of processing. Coffee husks and pulp are the major solid residues from the processing of coffee, for which there are no current profitable uses, and their adequate disposal constitutes a major environmental problem. Thus, in compliance with the concept of sustainable development, innovative techniques and products for the profitable and adequate use of this type of residue are being sought. Several research works presenting proposals for such endeavors have been published in the literature and are reviewed herein.

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... The bean comprises silver skin, an endosperm, and coffee seed [13,17]. The fruit (berry/cherry) usually bears two coffee beans [18] (Fig. 2). Coffee bean size varies; however, their average size 10 mm long and 6 mm wide [16]. ...
... Authors also indicated the potential of CH hydrolysate to be used as a substrate for bioprocesses. Valorization of CH to produce biogas [18,19], bioethanol, solid biofuels besides composting and vermicomposting [18] has also been reported. Bioethanol production from coffee mucilage [221,226] and coffee pulp [227], coffee residue [228] using Saccharomyces cerevisiae as yeast has been reported. ...
... Authors also indicated the potential of CH hydrolysate to be used as a substrate for bioprocesses. Valorization of CH to produce biogas [18,19], bioethanol, solid biofuels besides composting and vermicomposting [18] has also been reported. Bioethanol production from coffee mucilage [221,226] and coffee pulp [227], coffee residue [228] using Saccharomyces cerevisiae as yeast has been reported. ...
... Coffee is one of the most popular drinks in the world which generates significant amounts of agricultural waste. The amount of waste is ranging from 30% to 50% of the weight of the total coffee produced depends on how coffee was processed [6]. Wet processing of coffee usually produces coffeepulp as the first by-product obtained during processing and represents 29% dry-weight of the whole berry [6]. ...
... The amount of waste is ranging from 30% to 50% of the weight of the total coffee produced depends on how coffee was processed [6]. Wet processing of coffee usually produces coffeepulp as the first by-product obtained during processing and represents 29% dry-weight of the whole berry [6]. A number of method have been developed to utilize this source of biomass including chemical production, bio-fuel and others value added-products such as ethanol, single-cell protein, enzyme, organic acid, amino acid etc [6] [7][8]. ...
... Wet processing of coffee usually produces coffeepulp as the first by-product obtained during processing and represents 29% dry-weight of the whole berry [6]. A number of method have been developed to utilize this source of biomass including chemical production, bio-fuel and others value added-products such as ethanol, single-cell protein, enzyme, organic acid, amino acid etc [6] [7][8]. To our best knowledge, very limited number of work has focused on pyrolysis technology development for coffee-pulp. ...
... It is the second most commercialized product in the world after petroleum. It is so popular due to its aromatic and flavor characteristics as well as its stimulating and refreshing qualities [1][2][3]. Coffee is a high interest product to the agro-industrial sector in Mexico, second only to corn. The south and southeastern regions of Mexico are the second most important coffee producers worldwide thanks to the quality of its final processed product. ...
... In the base case or scenario A (S-A), the residual pulp, generated from the de-pulping process within the wet processing stage for the coffee [1,40], was treated through a composting process to produce a stabilized waste that was proposed to be used as fertilizer in the nursery stage [41,42]. Similarly, the residual straw, a solid sub-product generated during the hulling stage [3,43,44], was considered as fuel to supply hot air for the drying process of the coffee bean [45,46]. ...
... Table 4 shows there are big differences in this category depending on the scope of each study's setting. Through quantification of the mass and energy flow, the conclusion was that the coffee straw, generated from the cleaning sub-process [3,44], was not enough to supply the energy required to evaporate the water contained in the washed coffee bean, since the coffee must reduce from about 45% down to the 11% humidity required of the output product of this sub-stage, which is known as dry parchment coffee [55], as reported by Aguirre and Jacome, and Pozos and Moreno [33,53,56]. Therefore, scenario A included the use of not only the generated coffee straw, but also the use of wood-biomass energy through cutting or renovations from the coffee plant to supply the necessary energy. ...
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Coffee is the beverage resulting from the infusion of roasted and ground seeds of the coffee fruit. It is one of the most commercialized products in the world and represents a high interest agro-industrial product in Mexico. The demand for this product has grown in great measure in the last decade, thus it is becoming more important to make environmental and energetic evaluations of its manufacturing process. In this sense, life cycle assessment (LCA) is a useful tool for the purposes of this study, as it quantifies the wake of environmental impacts associated to the production and supply chain from its inputs and outputs of the product system. Therefore, the impact categories studied were carbon, energetic, and water footprints. The cultivation phase led to global contributions between 61% and 67% in magnitude for energy and carbon footprints, respectively; meanwhile, the coffee benefit process was the phase with the most contributions to the water footprint (54%). The residual biomass from the product system used as the energy supply within the coffee drying sub-phase represented energy savings of around 41% in comparison to the use of conventional fossil fuels, thus reducing the global impact associated to the system’s product.
... Coffee husk is a waste material obtained from coffee processing. Coffee is one of the top commodities produced and commercialized worldwide (Oliveira and Franca, 2015). Ethiopia produces coffee abundantly, 3.93 Â 10 8 kg coffee from an area of 5.32 Â 10 9 m 2 in 2017e2018 (FAS, 2017). ...
... Ethiopia produces coffee abundantly, 3.93 Â 10 8 kg coffee from an area of 5.32 Â 10 9 m 2 in 2017e2018 (FAS, 2017). Coffee processing generates significant amounts of agricultural waste, ranging from 30% to 50% the weight of the total coffee produced (Oliveira and Franca, 2015). Inapplicability of this solid residue can result in disposal and environmental problems. ...
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Various factors can affect the durability of roads, such as the strength of sub-grade, the quality of the sub-base and base course, the environments and properties of the soil used. Particularly, roads built on expansive soil are susceptible to early damage due to the swelling and shrinkage characteristics of this kind of soil under changing moisture conditions. The most common technique used to improve the properties of problematic soil is stabilization with additives. Using waste materials to improve the properties of expansive soil is a recent trend in soil stabilization. This study deals with the treatment of expansive soil with coffee husk ash (CHA). Coffee husk is a by-product of coffee production, and CHA is the resulting ash after burning it. In this study, the bearing capacity and compressibility characteristics of expansive soil (specifically black cotton (BC) soil) stabilized with varying percentages of CHA (5%, 10%, 15%, and 20%) are investigated. Then, scanning electron microscopy (SEM) and energy dispersive X-ray (EDX) were used to analyze the influence of CHA on surface morphology and chemical composition of the studied soil. The results showed that the soil treated with CHA is generally improved in terms of strength. Addition of 20% CHA increases the bearing capacity of the soil by three-fold. In addition, the morphological studies of the soil samples treated with 10% and 15% CHA indicated the formation of hydrated particles and cementitious compounds as a result of the reaction between the soil and CHA. This indicates the potential usage of CHA as a stabilization agent and subsequently, it can address the disposal and environmental concerns related to coffee husk. © 2019 Institute of Rock and Soil Mechanics, Chinese Academy of Sciences
... Coffee is the second largest commodity with its annual production increased from 140 to 152 million 60 kg bags since 2010 [1] [2]. Processing coffee berries yields residual about 30 -50% of its total weight depending on the type of processing [3]. The main residues obtained after removing coffee beans with dry or wet process are coffee pulp and husk. ...
... Uniformity in shape and size makes densified products easy to handle and store using the standard equipment. In general, pressure-assisted densification method can 3 To whom any correspondence should be addressed. [5]. ...
... Coffee pulp represents approximately 40 to 50% weight of the (Rolz et al., 1980;Hernandez et al., 2009; and its composition fluctuates depending on the coffee varieties; for example, wide ranges of macronutrients have been reported (per 100 g of dry matter): 4-12 g of protein, 1-2 g of lipids, and 45-89 g of carbohydrates (Oliveira and Franca, 2014;Salinas-Rios et al., 2014b), including pectin (Hasanah et al., 2019). Minerals such as P, K, Ca and Mg have been reported at 2.48, 25.13, 4.10 and 1.39 g/kg of coffee pulp, respectively, and those for Fe and Mn, at 77 and 46 mg/kg (Fierro-Cabrales et al., 2018). ...
... Minerals such as P, K, Ca and Mg have been reported at 2.48, 25.13, 4.10 and 1.39 g/kg of coffee pulp, respectively, and those for Fe and Mn, at 77 and 46 mg/kg (Fierro-Cabrales et al., 2018). The approximate percentage of caffeine is between 0.12 to 0.26% (Arimurti et al., 2017;Fierro-Cabrales et al., 2018), pectin and tannins range from 1-9 g/100 g of dry matter, or about 6% of the weight (Oliveira and Franca, 2014;Rakitikul, 2017). Coffee pulp also contains caffeic acid at about 16 mg/g dry matter, gallic acid at about 3 mg/g dry matter, and chlorogenic acid at about 62 mg/g dry matter (Salinas-Rios et al., 2014b;da Silveira et al., 2020). ...
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The coffee shell or pulp is the first by-product obtained from the processing of coffee. It represents approximately 40 to 50% of the coffee berry’s weight. Currently, in much of the industry, it is a waste product with a major environmental impact on the water and soil, flora and fauna, and a problem to nearby populations in terms of odor and proliferation of insects and pathogenic microorganisms. This is a review that compiles alternative uses of coffee pulp in agriculture, food and nutrition, medicine and biotechnology. In food and agriculture, for example, the pulp can be used as organic fertilizer to improve degraded soils, in the biological control of plant pathogens, as food or substrate for microorganisms and worms, as feed for chickens, sheep, goats, fish and other animals, and in the productions of foods and beverages for human consumption. In biotechnology, coffee pulp can be used in the cultivation of edible fungi, production of enzymes, substrate for caffeine degrading microorganisms and for microorganisms that produce natural fungicides. Although many of these applications have been proposed and studied, there are also several novel uses that are in the early stages of development; for example, the use of pulp bioactive compounds to make food supplements, or to increase dietary fiber contents in foods and beverages, as well as for the production of biocontainers and biopackaging, alternatives to plastics and their serious environmental impact.
... However, there were some attempts to detoxify it, which were reviewed in other works (Gokulakrishnan et al., 2005;Mazzafera, 2002). Oliveira and Franca (2015) presented an excellent and comprehensive review of the application of coffee husk. They reported multiple agricultural applications, such as the production of silages Neiva Júnior et al., 2007), composts (Degefe et al., 2012;Dzung et al., 2013;Rezende et al., 2012), or soil conditioners (Matos, 2008). ...
... There have been attempts to detoxify it, however, at present, it is still developing the concept and potential technology for the future, so it is essential to utilize it (Londoño-Hernandez et al., 2019). Due to the high organic matter content, it can be con- Oliveira and Franca, 2015;3 -Adams and Dougan, 1987;4 -Murthy and Madhava Naidu, 2012;5 -Porres et al., 1993;6 -Elias, 1979;7 -Bonilla-Hermosa et al., 2014;8 -Ulloa Rojas et al., 2003;9 -Gathuo et al., 1991;10 -Pandey et al., 2000. sidered promising raw material for various microbial processes or as fertilizer (Hughes et al., 2014). ...
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Coffee is one of the most popular beverages in the world, and its popularity is continuously growing, which can be expressed by almost doubling production over the last three decades. Cultivation, processing , roasting, and brewing coffee are known for many years. These processes generate significant amounts of by-products since coffee bean stands for around 50% of the coffee cherry. Therefore, considering the current pro-ecological trends, it is essential to develop the utilization methods for the other 50% of the coffee cherry. Among the possibilities, much attention is drawn to polymer chemistry and technology. This industry branch may efficiently consume different types of lignocellulosic materials to use them as fillers for polymer composites or as intermediate sources of particular chemical compounds. Moreover, due to their chemical composition, coffee industry by-products may be used as additives modifying the oxidation resistance, antimicrobial, or antifungal properties of polymeric materials. These issues should be considered especially important in the case of biodegradable polymers, whose popularity is growing over the last years. This paper summarizes the literature reports related to the generation and composition of the coffee industry by-products, as well as the attempts of their incorporation into polymer technology. Moreover, potential directions of research based on the possibilities offered by the coffee industry by-products are presented.
... Consumption of coffee, one of the most popular beverages in the world, provides health beneficial effects due to these phytochemicals. The role of coffee brew consumption in preventing some severe and prevalent diseases justifies its classification as a functional beverage (Dórea & da Costa, 2005;Oliveira & Franca, 2015). ...
... Despite the attempts and research activities made to utilize the coffee processing residues for several non-food uses, either economic feasibility or associated problems still exist inviting for further research (Oliveira & Franca, 2015). The same bioactive compounds recovered from coffee byproducts and similar food processing residues however demonstrated potential use in cosmetics (Galanakis, Tsatalas, & Galanakis, 2018b;2018aLee et al., 2013Bessada, Alves, & Oliveira, 2018. ...
Article
Research interests in coffee byproducts showed increased attraction. This is partly driven by the increasing annual coffee production, which leads to increased generation of solid residues creating environmental concern. Additionally, compositional profile of coffee byproducts stimulate more investigations into their role of affecting human physiological function. Driven by increased demand of valorizing agro-industrial residues into value added products, many research findings present justifiable importance and possible application of coffee byproducts in food. This extensive review therefore presents up-to-date information with reference to compositional data, potential of incorporating coffee byproducts as ingredients in food formulations and new product development with respect to their biological functionality and technological importance. Reviewed byproducts are coffee husk, pulp, parchment, silverskin and spent coffee ground. Processing steps are elaborated and description of each process with respect to characteristics of starting material and generated main products and resulting residues is made to clearly distinguish the corresponding byproducts. Respective nutritional and phytochemical composition, food formulation and their distinctive characteristics are described. Production of value added products and food product development as well as applications made so far to incorporate the byproducts into food formulation are reviewed. Finally, safety related references and prospective insights of coffee processing byproducts in the current changing economy with possible indication into future trend of the subject matter in universal context are presented.
... The processing of coffee generates significant amounts of agricultural waste, ranging from 30% to 50% the weight of the total coffee produced, depending on the type of processing. Coffee husks are the major solid residues from the processing of coffee, for which there are no current profitable uses, and their adequate disposal constitutes a major environmental problem [2]. Along the several steps of coffee production (from the small producers to the big companies of coffee processing and roasting) a huge amount of residues is generated. ...
... Along the several steps of coffee production (from the small producers to the big companies of coffee processing and roasting) a huge amount of residues is generated. For instance, in Brazil the production of coffee from 2008 to 2013 averaged 2.9 million tons, being generated about 1.4 million tons of wastes each year [2]. In this study, agricultural wastes like coffee husk ash had been used to improve geotechnical properties of a soil. ...
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The economic back ground of Ethiopian mostly dependent of agricultural products. So that in the time of agricultural development production of large amount of wastes requires disposal. In order to reduce the disposal problem, utilization of waste in civil engineering works is very important aspect. Agricultural waste reuse has gained high momentum for achieving sustainable waste management in recent times. Keeping this view in mind this study has been carried out to assess utilization of coffee husk ash for improving expansive black cotton soil to utilize as a subgrade material for road construction. Hence experimental investigations have been made to study the suitability of coffee husk ash to improve properties of expansive soil. The important geo-technical properties test was Specific gravity, Liquid limit, Plastic limit, Plasticity index, dry density and California Bearing Ratio values. Expansive soil covers large portion of Ethiopia, covering nearly 40% surface area of the Country. Jimma town exhibits such kind of soil as a subgrade material. They are characterized by their nature of expansion or shrinkage upon changes in moisture content. According to ERA 2002 this type of soils is poor for subgrade construction. The laboratory work involved sieve analysis along with consistence test to classify the soil sample. The preliminary investigation of the soil shows that it belongs to A-7-5 class of soil in AASHTO and CH in USCS soil classification system. Soils under this class are generally of poor engineering use. Atterberg limits, compaction and CBR tests were used to evaluate properties of stabilized soil. The soil was stabilized with coffee husk ash in stepped concentration of 5%, 10%, 15%, 20%, and 25% by dry weight of the soil. Analysis of the results shows the addition of coffee husk ash improve the geotechnical properties of the expansive black cotton soil. The addition of Coffee husk ash reduces plasticity index, swelling and OMC with an increase in MDD and CBR with all increased coffee husk ash contents. The addition of 20% and 25% of coffee husk ash established an increased CBR value by 252% and 296% respectively, indicating the subgrade class falling under S3. From this study it was found out that coffee husk ash stabilized soil do meet the minimum requirement of ERA pavement manual specification for use as a sub-grade material in road construction. Agricultural waste like coffee husk Ash have significant potential to be used in place of conventional material for various road constructions and should be projected for future construction.
... Currently, from the range of residues in the coffee processing chain, the coffee husks and coffee pulps have both applications as silage, due to their high concentration of potassium and other mineral nutrients, and for composting and vermicomposting [2,9]. For bioenergy generation, coffee husks have been utilized as a solid fuel for heat generation. ...
... For bioenergy generation, coffee husks have been utilized as a solid fuel for heat generation. Coffee pulps, a more abundant resource with higher moisture content, have had more applicability in biogas and bioethanol production [9]. On the other hand, the coffee grounds, obtained from the coffee brewing process, have potential applications in composting, like dietary fibre, and substrate for mushroom cultivation. ...
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The coffee industry constitutes an important part of the global economy. Developing countries produce over 90% of world coffee production, generating incomes for around 25 million smallholder farmers. The scale of this industry poses a challenge with the generation of residues along with the coffee cultivation and processing chain. Coffee stems, obtained after pruning of coffee trees, are one of those abundant and untapped resources in the coffee supply chain. Their high lignocellulosic content, the low calorific value ranging between 17.5 and 18 MJ kg⁻¹ and the low ash content make them a suitable solid fuel for thermochemical conversion, such as gasification. This research evaluates the feasibility of using these residues in small-scale downdraft gasifiers coupled to internal combustion engines for power and low-grade heat generation, using process modelling and the Colombian coffee sector as a case study. The producer gas properties (5.6 MJ Nm⁻³) and the gasifier’s performance characteristics suggest that this gas could be utilized for power generation. A cogeneration system efficiency of 45.6% could be attainable when the system’s low-grade heat is recovered for external applications, like in the coffee drying stage. An analysis of the energy demand and coffee stems availability within the Colombian coffee sector shows that the biomass production level in medium- to large-scale coffee farms is well matched to their energy demands, offering particularly attractive opportunities to deploy this bioenergy system. This work assesses the feasibility of providing coffee stem–sourced low-carbon energy for global coffee production at relevant operating scales in rural areas.
... The coffee pulp is one of the main byproducts derived from the wet processing of coffee; it is rich in carbohydrates, proteins, amino acids, mineral salts, tannins, polyphenols and caffeine (Dorsey and Jones, 2017). It has potentialities that are attractive to be used as raw material in different processes such as: production of bioethanol, bio-fertilizer, production of biogas, animal feed (Gurram et al., 2016;Durán et al., 2017), and as a pure or mixed substrate in the production of edible mushrooms (Oliveira and Franca, 2015). These technologies allow the use of an available and inexpensive substrate, eliminate pollution and in turn generate economic, social and environmental benefits (Chang, 2007). ...
... caffeine, tannins, and polyphenols) that can limit their direct use in soil or feed applications. However, they may be a good source of bioactive compounds that can be extracted and further used in food, cosmetics or pharmaceuticals (Mussatto, Machado, Martins, & Teixeira, 2011;Oliveira & Franca, 2015). Thus, the management and re-use of these high added-value residues can contribute to the sustainable development of the coffee chain itself, the global economy and, simultaneously, to a greener environment. ...
Article
Coffee silverskin is the major by-product of coffee roasting. Among all the coffee by-products, it is a relatively stable product due to its low moisture content. Currently, silverskin is used as direct fuel (e.g. firelighters), for composting and soil fertilization. As it is a natural source of several bioactive compounds that can be extracted and further used for food or dermocosmetic purposes, the valorization of this by-product is of utmost importance, having in view the sustainability and circular economy principles. The aim of this work was to evaluate, for the first time, the influence of different geographical origins (Brazil, Uganda, Vietnam, Cameroon, Indonesia, and India) on the chemical composition of silverskin obtained from Coffea canephora beans. Different parameters were analysed, including ashes, protein, soluble and insoluble fiber, and total lipid amounts; vitamin E, fatty acid and phenolics profiles (by HPLC-DAD-FLD, GC-FID, and HPLC-DAD, respectively); caffeine, 5‑caffeoylquinic acid and hydroxymethyfurfural contents (by HPLC-DAD); and antioxidant profile (total phenolics and flavonoids contents, DPPH[rad] inhibition, and Ferric Reducing Antioxidant Power). Significant differences (p < 0.05) were found between the samples, especially regarding the fatty acid profile and the antioxidant composition. For instance, the Brazilian silverskin was the richest in total lipids and vitamin E, while the Indian silverskin was the poorest in phenolics and antioxidant activity, and presented a higher relative percentage of saturated fatty acids. A Principal Component Analysis allowed to group the studied samples according to their geographical proximity.
... Another important industry waste in India arises from the agriculture sector, i.e. coffee husk, a waste generated from the coffee industry. It is well known that India is responsible for approximately 65% of world coffee production and 6 tonnes of cherry can produce 1 tonne of coffee husk (Franca and Oliveira 2015). The toxic content in the coffee husk limits its use for biofuel/mushroom cultivation. ...
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For the past 2 decades, electrical discharge-based non-thermal plasma is being utilized for the treatment of oxides of nitrogen and other hazardous air pollutants at the laboratory level. The discharge plasma exposure mainly results in oxidation of the gaseous pollutants necessitating usage of additional adsorbent/catalytic treatment. In this paper, the possibility of using the solid wastes from industries as a potential adsorbent for reducing oxides of nitrogen from diesel engine exhaust which is pre-treated with plasma discharges (direct plasma)/ozone mixing (indirect plasma) has been studied. Waste from agricultural industry (coffee husk), waste from marine industry (oyster shell), waste from metal casting industry (foundry sand), waste from aluminium extraction (red mud) and waste from thermal power plant (coal fly ash) have been used in this paper to study their gaseous pollutant adsorption capabilities. More than 90% reduction efficiency of oxides of nitrogen has been observed during the study. A comparative analysis of the industrial wastes has been made, and the synergistic effects have been discussed with respect to the plasma treatments. A new dimension to managing solid industrial wastes can be expected as a possible outcome of this work.
... Coffee cherries are picked from trees and processed to green beans following either the dry or the wet processing method [2]. For the dry method, the cherries are dried for 3 to 4 weeks after picking, before the outer fruit flesh is mechanically separated from the bean as dry husk, which is comprised of the pulp, mucilage and parchment [3]. For the wet method, the red cherries are processed to separate the pulp as one fraction, the mucilage as the second fraction and the parchment as the final one [4]. ...
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In this study, the anaerobic performance and stability of coffee husk and pulp with and without trace element (TE) supplement was investigated, using 20 L mesophilic continuous stirred tank reactors for 140 days of experiment (DOE). The TE was cocktail of trace metals composed of Fe, Ni, Zn, Co, Mn, Mo, Se W and B. The organic loading rate (OLR) was increased stepwise from 2.5 (HRT = 40 d) to 6.0 kg VS m⁻³ d 1(HRT = 16.7 d). The highest methane productivity from pulp with and without TE was 1.272 and 0.965 m³ m⁻³ d⁻¹ at an OLR of 6.0 and 5.0 kg VS m⁻³ d⁻¹; while the husks performed 0.895 and 0.795 m³ m⁻³ d⁻¹ respectively, both at an OLR of 6.0 kg VS m⁻³ d⁻¹. The specific methane yield (SMY) of pulp (at OLR = 5 kg VS m⁻³ d⁻¹) with and without TEs was 217.9 ± 4.7 and 193.1 ± 8.2 L kg−1 VS; while husk yielded 149.2 ± 6.0 and 132.5 ± 4.9 L kg−1 VS, respectively. The effect of TEs on SMY was statistically significant (p < 001) at higher OLRs (5.0 ‐ 6.0 kg VS m⁻³ d⁻¹). The TEs improved the anaerobic stability through an optimum alkalinity ratio (VFA/TIC < 0.3) and suppressed the accumulation of volatile fatty acids. Mono digestion of husks and pulp are prone to lack Mo, Zn, Ni and Fe in long‐term anaerobic fermentation. Further studies on co‐digestion of husk/pulp with animal manure and dry fermentation helps to efficiently use this biomass resource. This article is protected by copyright. All rights reserved
... However, coffee husks, obtained after de-hulling the coffee cherries during dry processing, also constitute a source of lignocellulosic materials, containing ∼57% of cellulosic and ∼22% lignin components (Moreno-Contreras, Serrano-Rico, & Palacios-Restrepo, 2009). Likewise, the coffee (Coffea sp.) crop generates a significant amount of waste, which could be used as a source of different valuable products (Alves, Rodrigues, Nunes, Vinha, & Oliveira, 2017), with a positive impact on the economy of producing countries, such as Brazil, Vietnam, Indonesia, Colombia, Ethiopia, India or Mexico (Oliveira & Franca, 2015). ...
... Estudios previos han presentado resultados de bioadsorción de metales pesados empleando materiales biológicos. Entre algunos de ellos está: cascarilla de arroz [22], cascarilla de café [23], cáscara de papa [24], quitosan de camarón [25], cenizas volantes y catalizador FCC (Catalizador gastado craqueo catalítico) [26,27], corteza de papaya [28], cáscara de huevo [29], cascarilla de garbanzo [30], cortezas de plátano (Musa AAA) [31] y cortezas de naranja (Citrus sinensis) [15]. Todos con eficiencias de remoción de metales pesados en rangos de 70 a 98%. ...
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In order to produce 1000 kg of leather, it is estimated of 85% of chemical input, used by European tanning plants, is discharged as contaminant. Among of them, Cr (VI), this is a toxic compound of easy adsorption. In that sense, the present work is focused on the removal of Cr (VI) in synthetic solution prepared from Cr (VI) estimated concentration found in wastewater sample discharged by tanning industries (Cr (VI): 32,6 mg/kg). Thus, five filters packed with orange (Citrus sinensis) and plantain (Musa AAB) peels were used in laboratory scale (Fa: 100% orange, Fb: 70% orange/30% plantain, Fc: 50% orange/50% plantain, Fd: 30% orange/70% plantain y Fe: 100% plantain). The main results show that among filters with the best performance in adsorption was Fd. Such filter had a removal efficiency of 93%, compare to Fa: 73%, Fb: 90%, Fc: 86% y Fe: 82%. Additionally, the adsorption constants found were between 96 and 132 mg Cr (VI)/gadsorb. Therefore, the combined bio-adsorbents (plantain/orange peels) could be highly recommended for Cr (VI) removal in tanning effluents.
... Brazil is the largest coffee producer and exporter in the world, also the second largest consumer. Coffee processing produces significant amounts of agricultural waste, depending on the type of processing ranging from 30% to 50% of the total weight of coffee produced, (Oliveira & Franca, 2014). Coffee production in Indonesia in 2017 reached 666,992 tons, resulting more than 66 thousand tons of agricultural waste. ...
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Indonesia is one of the coffee-producing countries where production tends to increase from year to year. Currently, residuals from coffee-fruit processing such as coffee-skin and husks are thrown away without any use and this biomass residual contains several toxic chemicals such as alkaloids, tannins, and polyphenols. One of potential uses of coffee-industry by-product is to make activated carbon (ACs), which is made through a carbonation process and followed by an activation process. In this study, chemical activation was carried out using chemical activators ZnCl2 and NaOH. The purpose of this study is to prepare and investigate the characteristics of chemically activated coffee skin bio-char focusing on the surface properties and iodine adsorption capacity. Prior to carbon activation, a purpose built pilot-scale reactor was fabricated and tested at temperatures of 400 °C and 500 °C. The difference in carbonation temperature and variations in activator concentration alter the absorption properties. The results showed that the coffee-skin pyrolyzed at 500 °C and activated by 2% NaOH solution exhibits the highest absorption value of 720.2 mg/g. Lower absorption values were observed in any ZnCl2 activator samples. SEM-EDS analysis result suggests significant changes in composition of the ACs before and after activation. Most of impurities are gone during activation and washing. The value of C atoms increases and the pores structure of the activated carbon are expanding showing suitable properties for adsorbent.
... In general, we can assume that coffee farm economics is dependent upon a wide variety of factors, including productivity, quality, costs of production and waste disposal, price premiums, the latter to achieve quality or sustainability standards. The options for the valorization of the coffee residues, not focusing on waste management in rural areas, have been recently reviewed [1,[3][4][5][6]. ...
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There are two problematic solid residues from agriculture and agro‐industry, produced in vast amounts in rural areas: those from coffee bean production and processing and those deriving from the extraction process of olive oil. Notwithstanding these residues originat‐ ing in different geographical areas, they have striking similarities. They both derive from traditional, conventional and organic agriculture; they have a high content in lignins, cel‐ luloses and (poly)phenols; they are produced in million tonnes annually; they pose rel‐ evant environmental problems for disposal; they contain bioactive compounds; and the approach for their re‐use is often similar, sometimes overlapping. The most promising re‐uses in rural areas are for agriculture, as animal feed and for energy production. There are also minor uses, suitable for the production of added‐value commodities. The re‐use will be dependent on a variety of factors according to the diversity of (a) pedoclimatic areas that include altitude and latitude, soil texture and organic matter content, water regime and availability, (b) level of expertise of the small farmers, (c) social environment that includes training opportunities and availability to create associative forms among producers, (d) access to trade and communication networks and (e) easy access to com‐ munity‐level processing installations. The perspectives of agronomic management and valorization are compatible with the objectives of a regenerative, sustainable agriculture.
... In this case, the one of potential biomass and also wastes of Indonesian agro-industry for methane production is coffee pulp. Coffee is a leading agro-industry commodity in Indonesia that generates significant amount of waste from its processing, ranging from 30-50 % of total weight of coffee produced, depending on the type of processing: wet or dry (Oliveira and Franca, 2016). Coffee husks and Coffee pulp are the major solid waste that can be produced during those processing. ...
Article
Coffee pulp is abundantly available in Indonesia every year, about 1.65 × 10^6 t of coffee pulp were produced during the 2011-2015. However, they have been poorly utilized or dumped in the environment. Meanwhile, utilizing coffee pulp for production of methane (CH4) is one of the most demanding technologies for production of environmentally friendly energy. This study aims to investigate the methane production from coffee pulp by some variables; microorganism existed in cow dung, rumen-fluid, and cow dung/rumen fluid mixture in anaerobic batch reactor with 3.6 L working volume at mesophilic temperature (30-35 °C). Some parameters such as Total Solid (TS), Volatile Solid (VS), Volatile Fatty Acids (VFAs), Chemical Oxygen Demand (COD) conversion and CH4 generated as a function of digestion time were analysed and compared with each variable and another substrate: rice straw. The result showed that the rate of TS, VS conversion of almost all digesters was low during 30 d of digestion. Consequently, a low of CH4 generated was detected, except in cow dung digester which had a higher concentration of CH4 after 20 d of digestion. The highest COD value decreasing was from cow dung reactor of 78.05 % that was converted to VFAs. The VFAs value was represented by acetic acid as the main substrate for generating CH4. The digestion rate was limited by bacteria growth because of the presence of toxic compounds in coffee pulp such as caffeine, tannin, and free phenol. Nevertheless, the conversion of TS, VS, COD and methane production still continued, though with a slower rate. At the final digestion time, the optimum accumulation of CH4 was generated from cow dung digester of 85.1 Ndm 3 /kgCOD removal, but it was approximately ten times as small as optimum accumulation of CH4 from rice straw. This shows that different substrate source can affect the amount of generated biogas.
... The coffee pulp is one of the main byproducts derived from the wet processing of coffee; it is rich in carbohydrates, proteins, amino acids, mineral salts, tannins, polyphenols and caffeine (Dorsey and Jones, 2017). It has potentialities that are attractive to be used as raw material in different processes such as: production of bioethanol, bio-fertilizer, production of biogas, animal feed (Gurram et al., 2016;Durán et al., 2017), and as a pure or mixed substrate in the production of edible mushrooms (Oliveira and Franca, 2015). These technologies allow the use of an available and inexpensive substrate, eliminate pollution and in turn generate economic, social and environmental benefits (Chang, 2007). ...
Article
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The search of the biotechnological ways to the integral use of the wastes generated by the coffee and citric agroindustries, is a current problem. The biotransformation of coffee pulp and orange mesocarp during aerobic and anoxic fermentation with the pectinolític yeast Kluyveromyces marxianus CCEBI 2011 was studied in this research. It was found that coffee pulp is a better substrate to yeast growth, which was evidenced throughout a better conversion of the carbon and energy source. The yeast used in 24 h the reducing and neutral sugars from substrates efficiently, either under aerobic or oxygen-limited cultures. The excretion of the polygalacturonase enzyme by the yeast lead to the increasing in the pectic substances extraction, which reached the 225 % and 33 % for coffee pulp and orange mesocarp, respectively, compared with the amounts which were extracted during substrates sterilization. The enzyme production by the microorganism presented not significantly differences in relation to the substrate used, but the contrary occurred with respect to glucose concentration in the medium. These results point to the promissory use of the K. marxianus CCEBI 2011 yeast strain in the valorization of pectin-rich agricultural wastes by means of their conversion in potential plant elicitors and prebiotics oligogalacturonides-based.
... Several studies have evaluated the use of coffee husks as a dietary supplement for cattle, swine, fish, sheep, chicken, and horses (Oliveira and Franca, 2014). The use of coffee husks as a supplement in cattle diets is considered feasible, with the limits for feed substitution in the range of 30%-40%. ...
Chapter
Approximately 90% of the edible parts of the cherry are discarded during its conversion into coffee brew. This chapter summarizes applications of coffee by-products as novel ingredients possessing biological, nutritional, and technological functions. Coffee cherries and their derivatives have potential as superfoods because they are composed of several phytochemicals with synergic biological effects and nutrients. They also have components with technological interest, which may be used as natural colorants, aromas, and texturizers, among others. Novel food products based on coffee wastes are being welcomed by Western consumers due to their well-known health-promoting and sensorial properties. Nowadays, several tasty foods and beverages from roasted coffee beans and coffee cherry by-products are available for commercialization. The number of commercial products based on coffee by-products has increased in the last few years, with the aim to achieve sustainable production and consumption of the coffee cherry.
... Along the several steps of coffee production (from the small producers to the big companies of coffee processing and roasting) a huge amount of residues is generated. For instance, in Brazil the production of coffee from 2008 to 2013 averaged 2.9 million tons, being generated about 1.4 million tons of wastes each year ( Oliveira and Franca, 2015). Considering all the producing countries, coffee wastes and by-products constitute a source of severe contamination and a serious environmental problem. ...
Chapter
This chapter describes the steps involved in coffee processing from the field to the cup and the respective generation of by-products along the chain. The chemical composition of coffee husks, pulp, immature, and defective beans, coffee silverskin, and spent coffee grounds is detailed and methods for the sustainable management of these by-products are addressed, as well as legislative frameworks and policy recommendations. Although coffee by-products have a high potential of application in different fields, more integrated strategies with the involvement of coffee producers, industries, academic institutions, governmental and nongovernmental organizations are still needed to convert coffee by-products into really profitable substrates.
... Nowadays, almost all countries have been facing the decreasing of fossil energy resource that can be a big problem if it not be solved wisely. A utilization of alternative energy such as bio-methane, hydrogen, biodiesel, bioethanol, solar cell, and etc. is considered as a prominent alternative to solve that problem [1][2][3][4]. One of them can be made from agricultural wastes such as corn, sugarcane bagasse, foliage, trunk, rice husk and coffee pulp as raw materials in their process [4]. ...
Conference Paper
Coffee is an excellent commodity in Indonesia that has big problem in utilizing its wastes. As the solution, the abundant coffee pulp waste from processing of coffee bean industry has been used as a substrate of biogas production. Coffee pulp waste (CPW) was approximately 48% of total weight, consisting 42% of the coffee pulp and 6% of the seed coat. CPW holds good composition as biogas substrate that is consist of cellulose (63%), hemicellulose (2.3%) and protein (11.5%). Methane production from coffee pulp waste still has much problems because of toxic chemicals content such as caffeine, tannin, and total phenol which can inhibit the biogas production. In this case, CPW was pretreated by ethanol/water (50/50, v/v) at room temperature to remove those inhibitors. This study was to compare the methane production by microbial consortium of cow dung and rumen fluid mixture coffee pulp waste as a substrate with and without pretreatment. The pretreated CPW was fermented with mixture of Cow Dung (CD) and Rumen Fluid (RF) in anaerobic co-digestion for 30 days at mesophilic temperature (30-40°C) and the pH was maintained from 6.8 to 7.2 on a reactor with working volume of 3.6 liters. There were two reactors with each containing the mixture of CPW without pretreatment, cow dung and rumen fluid (CD+RF+CPW) and then compared with the CPW with pretreatment (CD+RF+PCPW) reactor. The measured parameters included the decreasing of inhibitor compound concentration, Volatile Fatty Acids (VFAs), Chemical Oxygen Demand (COD), Total Solid (TS), Volatile Solid (VS), Methane and the Calorific value of gas (heating value) were studied as well. The result showed a decrease in inhibitor component concentration due to methanol pretreatment was 90% of caffeine; 78% of polyphenols (total phenol) and 66% of tannins. The highest methane content in biogas was produced in CD+RF+PCPW digester with concentration amounted of 44.56% with heating value of 27,770 BTU/gal.
... To date, several applications have been tested for coffee residues, mainly as biofuels, composts, animal feed, biosorbents and enzymes (Martinez-Saez et al., 2017). However Oliveira and Franca (2015) reported that there is still a need for significant research to make the energy recovery of coffee residues a technically and economically viable option. Since these residues are obtained at their processing facilities, the torrefaction pretreatment can be carried out on-site, decreasing the transportation costs and improving the economic feasibility of the chain. ...
Article
The aim of the present study is to analyze the influence of independent process variables such as temperature, residence time, and heating rate on the torrefaction process of coffee chaff (CC) and spent coffee grounds (SCGs). Response surface methodology and a three-factor and three-level Box-Behnken design were used in order to evaluate the effects of the process variables on the weight loss (WL) and the Higher Heating Value (HHV) of the torrefied materials. Results showed that the effects of the three factors on both responses were sequenced as follows: temperature > residence time > heating rate. Data obtained from the experiments were analyzed by analysis of variance (ANOVA) and fitted to second-order polynomial models by using multiple regression analysis. Predictive models were determined, able to obtain satisfactory fittings of the experimental data, with coefficient of determination (R²) values higher than 0.95.
... caffeine, tannins, and polyphenols) that can limit their direct use in soil or feed applications. However, they may be a good source of bioactive compounds that can be extracted and further used in food, cosmetics or pharmaceuticals (Mussatto, Machado, Martins, & Teixeira, 2011;Oliveira & Franca, 2015). Thus, the management and re-use of these high added-value residues can contribute to the sustainable development of the coffee chain itself, the global economy and, simultaneously, to a greener environment. ...
Article
Coffee silverskin (a coffee roasting by-product) contains high amounts of dietary fibre (49% insoluble and 7% soluble) and protein (19%). Potassium (∼5 g/100 g), magnesium (2 g/100 g) and calcium (0.6 g/100 g) are the major macrominerals. The vitamin E profile of silverskin comprises α-tocopherol), β-tocopherol, ɣ-tocopherol, δ-tocopherol, β-tocotrienol, ɣ-tocotrienol, and δ-tocotrienol. The fatty acid profile is mainly saturated (C16:0 and C22:0), but the total amount of fat is low (2.4%). Caffeine (1.25 g/100 g), chlorogenic acid (246 mg/100 g), and 5-hydroxymethylfurfural (5.68 mg/100 g) are also present in silverskin. Total phenolics and flavonoids are partially responsible for the in vitro antioxidant activity. Silverskin extracts protected erythrocytes from oxidative AAPH- and H2O2-induced hemolysis, but at high concentrations a pro-oxidant effect on erythrocyte morphology was observed.
... Value calculated considering that all rice produced is processed. f The amount of coffee husk and pulp corresponds to 30e50% of the weight of the total production (Oliveira & Franca, 2015). Value calculated considering that all coffee produced is processed. ...
Article
Full-text available
Background Aroma compounds can be produced using three main methods: chemical synthesis, extraction from nature, and biotechnological process (bioaromas). In the latter method, when compared with chemical synthesis and direct extraction from nature, the (bio)aroma compounds obtained present numerous advantages, in such a way that this approach meets two important demands of modern society: the first one refers to products obtained by biotechnological processes, which can be considered as natural, and the second one is related to the concept of sustainable development, since such production processes are aligned with the best practices in environmental preservation. Scope and approach In this review we demonstrate that the technological development of the production of aroma compounds using microorganisms is effectively promising as a process that allows the inextricably approach of the three pillars of sustainability: environment, economics, and social aspects. Key findings and conclusion This review shows that bioaroma production consists of renewable processes that employ mild conditions of operation, do not generate toxic waste, uses biodiversity rationally, and may also avail agro-industrial residues or by-products in a special way. Moreover, biological (e.g., antioxidant, anticancer, anti-inflammatory) activities attributed to some terpene biotransformation products are increasingly being reported, indicating that their applications may transcend food industry.
... The chemical composition of coffee husks and pulp does not differ dramatically, from a quantitative point of view, from that of coffee beans ( Table 3, [12]), except that there is lower content of lipids, different ratios among the glucidic fractions, and a higher content of minerals. However, both husks and pulp still contain caffeine, lignins and tannins. ...
Article
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Over ten million tonnes of solid residues are generated yearly from coffee agro-industry worldwide, along with larger amounts of wastewaters and cultivation residues. Both wastewaters and solid residues, such as defective coffee beans and spent coffee grounds, along with coffee husks (pulp and mucilage) that constitute around 60% of the wet weight of the fresh fruit, represent a relevant source of pollution and environmental threat, particularly from the widely adopted wet processing of coffee berries. Several attempts have been done to re-use the coffee processing solid residues, which include direct use as fuel in farms, animal feed, fermentation studies, adsorption studies, biodiesel production, briquetting, pelletizing, tannin extraction and production of specialty commodities. For the re-use of wastewaters, biogas production and direct delivery on plantations have been proposed or adopted, along with the treatment through infiltration, irrigation or (anaerobic) lagooning, reed bed and aerobic lagooning. In this study, the possible alternatives for the re-use and valorisation of the coffee processing and plantation are critically reviewed, taking into account the experiences with other agro-industrial residues and wastewaters, in the frame of a sustainable agro-industrial development.
... Estudios previos han presentado resultados de bioadsorción de metales pesados empleando materiales biológicos. Entre algunos de ellos está: cascarilla de arroz [22], cascarilla de café [23], cáscara de papa [24], quitosan de camarón [25], cenizas volantes y catalizador FCC (Catalizador gastado craqueo catalítico) [26,27], corteza de papaya [28], cáscara de huevo [29], cascarilla de garbanzo [30], cortezas de plátano (Musa AAA) [31] y cortezas de naranja (Citrus sinensis) [15]. Todos con eficiencias de remoción de metales pesados en rangos de 70 a 98%. ...
... More than 2.3 billion cups of coffee are consumed every day across the globe and the world's coffee production has attained an average of 7.5 million metric tons per year according to the International Coffee Organization [2]. The processing of coffee generates large quantities of agricultural waste, amounting to about 30-50% of the weight of the total coffee produced, depending on the processing method [3]. Coffee pulp and husks are among the largest solid residues resulting from coffee processing. ...
Article
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The utilization of the coffee husk fiber (CHF) from the coffee industry as a reinforcing filler in the preparation of a cost-effective thermoplastic based composite was explored in this study. The chemical composition and thermal properties of the CHF were investigated and compared with those of wood fiber (WF). CHF proved to be mainly composed of cellulose, hemicellulose and lignin, and exhibited similar thermal behavior to WF. High density polyethylene (HDPE) composites with CHF loadings of from 40 to 70% were prepared using melt processing and extrusion. The processing properties, mechanical behavior, water absorption and thermal performance of these composites were investigated. The effect of maleated polyethylene (MAPE) used as a coupling agent on the composite was explored. The experimental results showed that increasing the CHF loading in the HDPE matrix resulted in an increase in the modulus and thermal properties of the composites, but resulted in poor water resistance. The addition of a 4% MAPE significantly improved the interfacial behavior of the hydrophilic lignocellulosic fiber and the hydrophobic polymer matrix.
... In the processing of coffee beans, dehydrated coffee husks and pulp (DCHP) are generated byproducts sold at relatively low prices, mostly for use as chicken bedding. Efforts have been dedicated to identify other uses for DCHP, one being for mulching of different crops (Braham and Bressani 1979;Oliveira and Franca 2015). DCHP is not expected to contain an appreciable number of Gamasina mites, given that the material is kept under dry conditions between its production and use. ...
Article
Full-text available
Mulching of soil beds of strawberry fields is usually done with polyethylene film in southern Minas Gerais state, Brazil. This material is relatively expensive and difficult to discard after use. In some countries, mulching is done with the use of organic material that could have an advantage over the use of plastic for its easier degradation after use, and for favoring edaphic beneficial organisms. Predatory mites (especially Gamasina, Mesostigmata) may be abundant in the soil and could conceivably move to the soil surface and onto the short-growing strawberry plants at night, helping in the control or pest arthropods. The two-spotted spider mite, Tetranychus urticae Koch, is considered an important strawberry pest in that region, where the fungus Neozygites floridana (Weiser and Muma) has been found to infect it. Different mulching types could affect the incidence of this pathogen. Dehydrated coffee husk and pulp (DCHP) is a byproduct readily available in southern Minas Gerais, where could be used as organic mulching in strawberry beds. The temporary contact of that material with the soil of a patch of natural vegetation could facilitate its colonization by edaphic predatory mites helpful in the control of strawberry pests. The objective of this work was to study the effect of mulching type on the population dynamics of the two-spotted spider mite, associate mites and N. floridana, in a greenhouse and in the field. The use of DCHP increased the number of edaphic Gamasina on strawberry plants—Proctolaelaps pygmaeus (Müller) (Melicharidae) and Blattisocius dentriticus (Berlese) (Blattisociidae) were observed on strawberry leaflets, mainly in nocturnal samplings, indicating their possible daily migration from soil to plants. Lower levels of two-spotted spider mite occurred on plants from pots or soil beds mulched with DCHP instead of polyethylene film, possibly because of the slightly higher levels of mites of the family Phytoseiidae and infection by N. floridana. Adding DCHP onto the floor of natural vegetation did not result in higher diversity or levels of gamasine mites on DCHP. Complementary studies should be conducted to find ways to increase diversity and density of those organisms in strawberry beds, in an attempt to improve biological control of strawberry pests. The decision to use DCHP for mulching should also take into account other factors such as strawberry yield, costs and efficiency of weed management, to be evaluated in subsequent studies.
... At the same time that pectic enzymes are produced by fermentation, the coffee pulp is transformed and detoxified (Mazzafera, 2002;Londoño-Hernandez et al., 2020), being also able for some of the uses mentioned above (Murthy and Naidu, 2012b). There is still need for research in alternative and profitable uses of coffee pulp (Oliveira and Franca, 2015) and, for that reason, the use of the pulp for the production of pectic enzymes by solid state fermentation requires further research. In this sense, the objective of this work was the evaluation of the coffee pulp as substrate for polygalacturonase production in solid state fermentation through a study of the physicochemical characteristics of the coffee pulp and its structural cell wall polysaccharides, together with the establishment of the biochemical characteristics of the produced polygalacturonase by an Aspergillus niger strain isolated from the same coffee pulp and coffee bean. ...
Article
Full-text available
The purpose of this research is to evaluate the coffee pulp, a by-product of coffee processing, as substrate for polygalacturonase production by solid state fermentation. In addition, it is a way to take advantage of the coffee pulp. Characterization of the coffee pulp revealed a high content of nutrients for fungi growth, such as reducing sugars (5.4% of dry pulp), proteins (9.4% of dry pulp), pectins (20.5% of dry pulp), which are inducers of pectic hydrolases production and source of carbon after degradation, and caffeine (1.4% of dry pulp), among others. The characterization of the cell-wall of coffee pulp revealed, after polysaccharides fractionation, the content in cell-wall pectins (25.5%), hemicelluloses (11.5%) and cellulosic residue (44%). A strain of Aspergillus niger, called van Thiegem, has been selected as a good producer of polygalacturonases (60 U/ml) using the coffee pulp as the growth substrate. During fermentation, reducing sugars, caffeine and phenolic compounds were consumed till almost exhaustion. A partial characterization of the polygalacturonase using high methoxyl pectin as substrate indicates an optimal pH of 4.0 and 45oC as optimal temperature, which are good values for the use of the enzyme in vegetable processing, including coffee processing.
... Coffee processing can be done by dry or wet routes, generating different types of residues [4]. According to Setter et al. [5], the most used method in Brazil is dry processing, with the main residue generated being the husk obtained with a yield of approximately 50% of the weight of the coffee beans. ...
Article
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Coffee husks (Coffea arabica L.) are characterized by exhibiting secondary metabolites such as phenolic compounds, which can be used as raw material for obtaining bioactive compounds of interest in food. The objective of this study is to evaluate different methods for obtaining the raw material and extracting solutions of bioactive compounds from coffee husks. Water bath and ultrasound-assisted extraction methods were used, using water (100%) or ethanol (100%) or a mixture of both (1:1) as extracting solutions and the form of the raw material was in natura and dehydrated. The extracts were evaluated by their antioxidant potential using DPPH radicals, ABTS, and iron reduction (ferric reducing antioxidant power (FRAP)), and later total phenolic compounds, total flavonoids, and condensed tannins were quantified the phenolic majority compounds were identified. It was verified that the mixture of water and ethanol (1:1) showed better extraction capacity of the compounds with antioxidant activity and that both conventional (water bath) or unconventional (ultrasound) methods showed satisfactory results. Finally, a satisfactory amount of bioactive compounds was observed in evaluating the chemical composition (total phenolic compounds, total flavonoids, condensed tannins, as well as the analysis of the phenolic profile) of these extracts. Corroborating with the results of the antioxidant activities, the best extracting solution was generally the water and ethanol mixture (1:1) using a dehydrated husk and water bath as the best method, presenting higher levels of the bioactive compounds in question, with an emphasis on chlorogenic acid. Thus, it can be concluded that the use of coffee husk as raw material to obtain extracts of bioactive compounds is promising. Last, the conventional method (water bath) and the water and ethanol mixture (1:1) stood out among the methods and extracting solutions used for the dehydrated coffee husk.
... There are no commercially available products containing these potential novel ingredients. It is important for coffee industries to make an effort to valorize CS and SCGs from coffee processing to increase the sustainability of the process, increase economical income and create new jobs in producing countries [11]. ...
Article
Full-text available
To obtain the coffee beverage, approximately 90% of the edible parts of the coffee cherry are discarded as agricultural waste or by-products (cascara or husk, parchment, mucilage, silverskin and spent coffee grounds). These by-products are a potential source of nutrients and non-nutrient health-promoting compounds, which can be used as a whole ingredient or as an enriched extract of a specific compound. The chemical composition of by-products also determines food safety of the novel ingredients. To ensure the food safety of coffee by-products to be used as novel ingredients for the general consumer population, pesticides, mycotoxins, acrylamide and gluten must be analyzed. According with the priorities proposed by the Food Agriculture Organization of the United Nations (FAO) to maximize the benefit for the environment, society and economy, food waste generation should be avoided in the first place. In this context, the valorization of food waste can be carried out through an integrated bio-refinery approach to produce nutrients and bioactive molecules for pharmaceutical, cosmetic, food and non-food applications. The present research is an updated literature review of the definition of coffee by-products, their composition, safety and those food applications which have been proposed or made commercially available to date based on their chemical composition.
... Researches on the use of enzymes in coffee processing has been increasing, since coffee is a beverage with a characteristic aroma and flavor of great popularity in terms of world consumption [1] and is classified as commodities only losing to petroleum in terms of world trade marketed currency [2]. After water, coffee and tea are the two most commonly consumed beverages worldwide. ...
Article
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Coffee, one of the world’s most consumed beverages, is recognized for its peculiar aroma and flavor. Depending on the type of coffee processing, different co-products are generated as lignocellulosic materials that comprise husks, skin, pulp, mucilage, parchment, coffee silverskin and spent coffee grounds. These co-products could be converted into a highly attractive substrate for bioconversion processes, and they can be used due to their high added value. According to the type of coffee co-product and its chemical composition, different enzymatic technologies can be used like enzyme production, enzymatic hydrolysis, enzyme-assisted extraction, and others. The application of enzymatic processes for biomass reuse has been increasingly desired for being an environmentally friendly alternative improving the management of the vast quantity of waste generated by the coffee industry. Graphic Abstract
... A global increase in coffee production also results in a huge number of residues. The residues contain caffeine, polyphenol and tannin that may cause severe contamination and serious environmental problems if not treated properly (Murthy and Naidu, 2012;Oliveira and Franca, 2015;Alves et al., 2017). ...
Article
Full-text available
Coffee pulp which is a by-product of coffee production contains considerable amounts of phenolic compounds that can be valorised to produce cascara as an antioxidant beverage. The fermentation and drying conditions of the coffee pulp have a great influence on the bioactive compounds in the cascara. This study aimed to investigate the effect of natural fermentation with simultaneous aeration on the phenolic content and antioxidant activity of cascara. A systematic study was carried out using a response surface methodology with a face-centered central composite design to determine the effect of fermentation time (0–8 h) and temperature (27–37 °C) on the number of bacteria in the coffee pulp after natural fermentation with simultaneous aeration (an air flowrate of 4 m/s) as well as phenolic content and antioxidant activity of cascara. The experimental dataset was modelled with an empirical model using multi-variable non-linear regression. A good agreement between model and experimental data was obtained. At the optimum conditions (4.2 h, 31.8 °C), the phenolic content was 6.72% whereas the antioxidant activity was 27.6%. Indigenous lactic acid bacteria were also isolated from the coffee pulp and determined as Leuconostoc pseudomesenteroides. The isolated bacteria can be used as a starter for controlled fermentation of coffee pulp as it increased the antioxidant activity up to 15% higher than the antioxidant activity of cascara obtained at the optimum conditions for natural fermentation with simultaneous aeration and 30% higher from the fresh coffee pulp.
... According to the International Coffee Organization (ICO), in 2018, the world coffee production was 168.093 million bags of 60 kg. Its processing generates significant amounts of agricultural waste, ranging from 30% to 50% of the total coffee weight produced, depending on the type of processing (Oliveira and Franca, 2015). According to Mussatto et al. (2011), approximately 50% of the world's coffee production is used to prepare soluble, and the ground coffee residues are in the order of 6 million tons per year, worldwide. ...
Article
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This research aimed to evaluate the adsorption process of cyanide ion (CN-) contained in synthetic aqueous solution, using activated carbon obtained from coffee residue, studying its efficiency and equilibrium and kinetic models. Activated carbon was characterized by Fourier Transform infrared analysis (FTIR), X-ray diffraction (DRX), and iodine number determination. A central composite design (CCD) with three factors adapted to three levels each and six central points was applied to study the effect of pH (A), contact time (B) and adsorbent dosage (C); According to the analysis of variance, the factors A, B, C, and the square AA were significant in the adsorption efficiency of cyanide onto activated carbon, whose maximum value reached was 54.68% and 67.65% for the predictive level. According to the coefficient of determination (R 2), Freundlich's isothermal model (0.954) and the three kinetic equations of pseudo-second order (0.991, 0.993, 0.993) fit the experimental process. From the results obtained, the active carbon prepared from coffee residue can be used as a potential adsorbent of CN-, contained in aqueous solutions of low concentrations. Abstract-This research aimed to evaluate the adsorption process of cyanide ion (CN-) contained in synthetic aqueous solution, using activated carbon obtained from coffee residue, studying its efficiency and equilibrium and kinetic models. Activated carbon was characterized by Fourier Transform infrared analysis (FTIR), X-ray diffraction (DRX), and iodine number determination. A central composite design (CCD) with three factors adapted to three levels each and six central points was applied to study the effect of pH (A), contact time (B) and adsorbent dosage (C); According to the analysis of variance, the factors A, B, C, and the square AA were significant in the adsorption efficiency of cyanide onto activated carbon, whose maximum value reached was 54.68% and 67.65% for the predictive level. According to the coefficient of determination (R 2), Freundlich's isothermal model (0.954) and the three kinetic equations of pseudo-second order (0.991, 0.993, 0.993) fit the experimental process. From the results obtained, the active carbon prepared from coffee residue can be used as a potential adsorbent of CN-, contained in aqueous solutions of low concentrations.
... According to the International Coffee Organization (ICO), in 2018, the world coffee production was 168.093 million bags of 60 kg. Its processing generates significant amounts of agricultural waste, ranging from 30% to 50% of the total coffee weight produced, depending on the type of processing (Oliveira and Franca, 2015). According to Mussatto et al. (2011), approximately 50% of the world's coffee production is used to prepare soluble, and the ground coffee residues are in the order of 6 million tons per year, worldwide. ...
Article
Full-text available
This research aimed to evaluate the adsorption process of cyanide ion (CN-) contained in synthetic aqueous solution, using activated carbon obtained from coffee residue, studying its efficiency and equilibrium and kinetic models. Activated carbon was characterized by Fourier Transform infrared analysis (FTIR), X-ray diffraction (DRX), and iodine number determination. A central composite design (CCD) with three factors adapted to three levels each and six central points was applied to study the effect of pH (A), contact time (B) and adsorbent dosage (C); According to the analysis of variance, the factors A, B, C, and the square AA were significant in the adsorption efficiency of cyanide onto activated carbon, whose maximum value reached was 54.68% and 67.65% for the predictive level. According to the coefficient of determination (R2), Freundlich's isothermal model (0.954) and the three kinetic equations of pseudo-second order (0.991, 0.993, 0.993) fit the experimental process. From the results obtained, the active carbon prepared from coffee residue can be used as a potential adsorbent of CN-, contained in aqueous solutions of low concentrations.
... Africa produces annually approximately 1 million tons of coffee (International Coffee Organization, 2019), the largest coffee exporting countries being located in the sub-Saharan regions of the continent. During processing, agricultural residues such as tree branches and leaves form up to 50 % of the total weight of coffee products (Oliveira and Franca, 2015), and investigations of using these residues to support the sustainable development of sub-Saharan Africa are ongoing. The coffee husk (CH) used in this study was collected from Kenya, where Coffea arabica is the dominant coffee species. ...
Article
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This research was part of the Salutary Umeå Study of Aerosols in Biomass Cookstove Emissions (SUSTAINE) laboratory experiment campaign. We studied ice-nucleating abilities of particulate emissions from solid-fuel-burning cookstoves, using a portable ice nuclei counter, Spectrometer Ice Nuclei (SPIN). These emissions were generated from two traditional cookstove types commonly used for household cooking in sub-Saharan Africa and two advanced gasifier stoves under research to promote sustainable development alternatives. The solid fuels studied included biomass from two different African tree species, Swedish softwood and agricultural residue products relevant to the region. Measurements were performed with a modified version of the standard water boiling test on polydisperse samples from flue gas during burning and size-selected accumulation mode soot particles from a 15 m3 aerosol-storage chamber. The studied soot particle sizes in nanometers were 250, 260, 300, 350, 400, 450 and 500. From this chamber, the particles were introduced to water-supersaturated freezing conditions (−32 to −43 ∘C) in the SPIN. Accumulation mode soot particles generally produced an ice-activated fraction of 10−3 in temperatures 1–1.5 ∘C higher than that required for homogeneous freezing at fixed RHw=115 %. In five special experiments, the combustion performance of one cookstove was intentionally modified. Two of these exhibited a significant increase in the ice-nucleating ability of the particles, resulting in a 10−3 ice activation at temperatures up to 5.9 ∘C higher than homogeneous freezing and the observed increased ice-nucleating ability. We investigated six different physico-chemical properties of the emission particles but found no clear correlation between them and increasing ice-nucleating ability. We conclude that the freshly emitted combustion aerosols form ice via immersion and condensation freezing at temperatures only moderately above homogeneous freezing conditions.
... According to the International Coffee Organization (ICO), in 2018, the world coffee production was 168.093 million bags of 60 kg. Its processing generates significant amounts of agricultural waste, ranging from 30% to 50% of the total coffee weight produced, depending on the type of processing (Oliveira and Franca, 2015). According to Mussatto et al. (2011), approximately 50% of the world's coffee production is used to prepare soluble, and the ground coffee residues are in the order of 6 million tons per year, worldwide. ...
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... It is evident from the literature that carbohydrates and amines are widely used as fuels in the solution combustion synthesis [28,29]. Presence of biomolecules such as carbohydrates (58%-85%), proteins (8%-11%), polyphenols, tannins etc. play an important role as fuel and amine-containing molecules possess good chelating ability and aid in better combustion [30,31]. Despite several reports on the use of various organic compounds as fuels, use of agro-waste extract as a cost-effective and eco-friendly fuel is limited. ...
... tons/year of the coffee pulp (coffee husks) (Yufniati, 2015). Investigation results show that fresh coffee husks is very potential as a source of anthocyanin which can be applied as a natural dye (Oliveira & Adriana, 2015). ...
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... It is abundant where Indonesia is the fourth largest coffee producer country in the world with 620,000 tons production in 2019 [3]. About 30-50% of the total weight of coffee cherries is CPW [4]. ...
... In the case of calcium alginate its ability to adsorb dyes has been studied, where it is suggested that it absorbs and immobilizes these contaminants (Jeon, Lei & Kim, 2008). For agroindustrial matrices it was found that they have the ability to discolor, possibly as calcium alginate has the ability to adsorb the dye (Oliveira & Franca, 2015;Tahir et al., 2016). However, these sorption phenomena do not ensure the breakdown of the chemical bonds of the dyes and this is why biological systems are an attractive alternative for the treatment of wastewater with different contaminants such as dyes (Bai et al., 2010). ...
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... For dry processing, the cherries, regardless of their state of ripeness (ripe, unripe and overripe), are harvested simultaneously by stripping them from the branches, thus demanding less labor than the wet method. The whole cherries are dried for 3-4 weeks to reach a moisture content of 10-11% [3,4]. The husk is mechanically separated from the beans as a single-fraction comprising the outer skin, pulp, mucilage and parchment. ...
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Activated carbons (ACs) with a highly developed porosity have been prepared from a lignocellulosic precursor (coffee husk) for environmental pollutant adsorption. Characterization results show that these materials exhibit a high amount oxygen groups and high specific surface area with micro mesopores. From SEM results we can see the collapse of large pores at longer activation times. The ACs obtained from coffee husk waste is a promising adsorbent material, with high adsorption capacity for the methylene blue dye (MB). Thus, the use of the coffee husk for AC preparation, with porosity development, showed as a good alternative for the waste transformation. Results also showed that the adsorption of MB by the AC-1/1 was much better than commercial AC from Merck.
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Coffee pulp is the main solid residue from the wet processing of coffee berries. Due to presence of anti-physiological and anti-nutritional factors, coffee pulp is not considered as adequate substrate for bioconversion process by coffee farmers. Recent stringent measures by Pollution Control authorities, made it mandatory to treat all the solid and liquid waste emanating from the coffee farms. A study was conducted to evaluate the efficiency of an exotic (Eudrilus eugeniae) and a native earthworm (Perionyx ceylanesis) from coffee farm for decomposition of coffee pulp into valuable vermicompost. Exotic earthworms were found to degrade the coffee pulp faster (112 days) as compared to the native worms (165 days) and the vermicomposting efficiency (77.9%) and vermicompost yield (389 kg) were found to significantly higher with native worms. The multiplication rate of earthworms (280%) and worm yield (3.78 kg) recorded significantly higher with the exotic earthworms. The percentage of nitrogen, phosphorous, potassium, calcium and magnesium in vermicompost was found to increase while C:N ratio, pH and total organic carbon declined as a function of the vermicomposting. The plant nutrients, nitrogen (80.6%), phosphorus (292%) and potassium (550%) content found to increase significantly in the vermicompost produced using native earthworms as compared to the initial values, while the calcium (85.7%) and magnesium (210%) content found to increase significantly in compost produced utilizing exotic worms. Vermicompost and vermicasts from native earthworms recorded significantly higher functional microbial group's population as compared to the exotic worms. The study reveals that coffee pulp can be very well used as substrate for vermicomposting using exotic (Eudrilus eugeniae) and native earthworm (Perionyx ceylanesis).
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Coffee husk and coffee pulp are coffee processing by-products. Coffee husk is obtained when harvested coffee is processed by the dry method, and coffee pulp is produced by the wet method. In Brazil, coffee is usually processed by the dry method, therefore an expressive amount of husk is obtained every year. Some of the husk is used as organic fertilizer but, other applications are very limited, mainly because it is a bulky product. The presence of tannins and caffeine diminish acceptability and palatability of husk by animals. This review discuss degradation of caffeine by microorganisms, with special attention to bacterial, biological decaffeination of coffee husk and pulp and its subsequent use on animal feeding. The known biochemical routes of caffeine degradation by microorganisms are initially discussed; problems concerning physiological effects in animals, focusing on the limitations imposed by caffeine as an antiphysiological component are raised; the use of microorganisms to decaffeinate coffee husk and pulp is discussed. The discussions offer a view on decreasing caffeine content of coffee husk and pulp, which would allow the use of larger amounts of these products in animal feeding, partially replacing traditional components such as cereal grains.
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The objective of this work was to evaluate the feasibility of ethanol production by fermentation of coffee husks by Saccharomyces cerevisiae. Batch fermentation studies were performed employing whole and ground coffee husks, and aqueous extract from ground coffee husks. It was observed that fermentation yield decreased with an increase in yeast concentration. The best results were obtained for the following conditions: whole coffee husks, 3 g yeast/l substrate, temperature of 30 degrees C. Under these conditions ethanol production was 8.49 +/- 0.29 g/100 g dry basis (13.6 +/- 0.5 g ethanol/l), a satisfactory value in comparison to literature data for other residues such as corn stalks, barley straw and hydrolyzed wheat stillage (5-11 g ethanol/l). Such results indicate that coffee husks present excellent potential for residue-based ethanol production.
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Ferric chloride was used as a new activating agent, to obtain activated carbons (AC) from agro industrial waste (coffee husks). This material was compared with two samples from the same raw material: one of them activated by using the classical activating agent, zinc chloride, and the other, activated with a mixture of the two mentioned activating agents in the same mass proportion. The carbonaceous materials obtained after the activation process showed high specific surface areas (BET), with values higher than 900 m(2)g(-1). It is interesting to observe that the activation with FeCl(3) produces smaller pores compared to the activation with ZnCl(2). An important fact to emphasize in the use of FeCl(3) as activating agent is the activation temperature at 280 degrees C, which is clearly below to the temperature commonly employed for chemical or physical activation, as described in the bibliography. All the studied materials showed different behaviors in the adsorption of methylene blue dye and phenol from aqueous solutions.
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The green coffee bean of international commerce constitutes only 50–55% of the dry matter of the ripe cherry (18% on a fresh weight basis). The remaining material is diverted into a variety of low- or negative- value by-products depending on the processing technique used. Here we describe these by-products and the various schemes that have been proposed for their utilisation or disposal, and attempt a critical evaluation of their feasibility. Aspects of this subject have been discussed previously by several authors.1 – 6
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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.
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This 90 days vermicomposting work was conducted to evaluate the performance of epigeic earthworms E.andrei to alter and change four commonly dumped and littered solid wastes in Ethiopian cities and towns in to a high quality vermicompost. All wastes were mixed with cow dung in 3:1 ratio and treated with earthworm E.andrei in the following waste and worm mass proportion. 9kg of vegetable waste treated with 130gm of worms, 9kg of enset waste treated with 130gm of worms, 5kg of coffee husk treated with 70gm of worms, 8kg of khat waste treated with 115gm of worms. Results from all beddings treated by this species of earthworms showed that TKN increased b/n 50.3 - 56%, TK increased between 29.6 - 43.6 %, TP increased between 58.9% - 73.2%, Ca increased between 39.6 % - 61.5%, while TOC decreased between 35% - 38.4 % and the C:N ratio reduced between 60 - 68 %. The findings from this experiment generally indicated that vermicomposting could be one good option to improve solid waste management performance of Ethiopian cities and towns through the production of excellent biofertilizer for agronomic purpose.
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The agro and industrial activities are actually responsible for the production of large amounts of solid wastes in Brazil. The use of industrial wastes as alternative raw materials into ceramic products has been widely developed. The typical materials used in the ceramic formulations present a large diversification of chemical compositions, what allow the incorporation of different types of waste materials in the ceramic mixture. Brazil produces a massive amount of coffee and the lack of adequate landfill areas available to dispose the coffee’s husk ash reject material are causing an ambiental problem for the agro-industry. This work describes research carried out on the thermal characterization and X-ray diffraction of coffee’s husk ash reject and its possible use in the ceramic industry.
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Coffee is one of the popular beverages of the world and second largest traded commodity after petroleum. Coffee is cultivated in about 80 countries across the globe and entangles huge business worldwide. Coffee dispensation requires an elevated degree of processing know how and produces large amounts of processing by-products such as coffee pulp and husk, which have limited applications such as fertilizer, livestock feed, compost and such others. Biotechnological applications in the field of industrial residues management promote sustainable development of country's economy. The objectives pertaining to food processing by-products, waste and effluents include the recovery of fine chemicals and production of precious metabolites via chemical and biotechnological processes. Pre-treatments, followed by recovery procedures endow value-added products (natural antioxidants, vitamins, enzymes, cellulose, starch, lipids, proteins, pigments) of high significance to the pharmaceutical, cosmetic and food industries. With the background of high crop production in the upcoming years, there is an imperative need to counterpart this production with some utilization and industrial application of coffee by-products since coffee industry emerges enormous amounts of coffee by-products which are thriving nutrient resources. The present review highlights explorations of value addition to coffee by-products which can be achieved with valorization strategy, integration of techniques and applications of bioengineering principles in food processing and waste management and secondly conserve environment with disposal problem accelerating both ecological and economical resources.
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Gluconacetobacter, a bacterial cellulose (BC)-producing organism, has ability to utilise pectin and phenolic compounds. The extract of coffee cherry husk (CCH), a high pectin- and polyphenol-containing agro waste was used in the study. Production of endo- and exo-polygalacturonase, polyphenol oxidase and tannase was observed during fermentation. Co-utilisation of glucose and galacturonic acid was observed. Accumulation of rhamnose, arabinose and galactose indicated the breakdown of pectin. Among the phenolic acids, benzoic acid derivatives were found to be degraded faster than cinnamic acid derivatives. Degradation of tannic acid was more pronounced among the bound forms than free forms in the culture broth. In BC, accumulation of free tannic, gentisic and coumaric acids was observed during the 2nd week of fermentation. The present work indicates the ability of the organism to produce BC by the utilisation of agro waste like CCH.
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This paper describes the conventional and microwave-assisted pyrolysis of coffee hulls at 500, 800 and 1000 °C. The influence of the pyrolysis method and temperature on the product yields and on the characteristics of the pyrolysis products is discussed. It was found that the pyrolysis of this particular residue gives rise to a larger yield of the gas fraction compared to the other fractions, even at relatively low temperatures. A comparison of microwave-assisted pyrolysis and conventional pyrolysis showed that microwave treatment produces more gas and less oil than conventional pyrolysis. In addition, the gas from the microwave has much higher H2 and syngas (H2 + CO) contents (up to 40 and 72 vol.%, respectively) than those obtained by conventional pyrolysis (up to 30 and 53 vol.%, respectively), in an electric furnace, at similar temperatures. From the pyrolysis fraction yields and their higher heating values it was found that the energy distribution in the pyrolysis products decreases as follows: gas > solid > oil. Moreover, the energy accumulated in the gas increases with the pyrolysis temperature. By contrast, the energy accumulated in the char decreases with the temperature. This effect is enhanced when microwave pyrolysis is used.
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Activated carbons (Acs) were prepared by pyrolysis of coffee bean husks in presence of phosphoric acid (chemical activities). Husks from Colombian coffee beans were impregnated with aqueous solutions of H3PO4 following a variant of the incipient wetness method. Diffenent concentrations were used to produce impregnation ratios of 30, 60, 100 and 150 wt.%. Activation was carried out under argon flow by heating to 723 K with 1 h soaking time. The porous texture of the obtained ACs was characterized by physical adsorptions of N2 at 77 K and CO2 at 273 K. The impregnation ration had a strong influence on the pore structure of these Acs, which could be easily controlled by simply varying the proportion of H3PO4 used in the activation. Thus, low impregnation ratio led to essentially microporous Acs. At intermediate impregnation ratios, ACs with wider pore size distribution (from micropores to mesopores) were obtained. Finally, high impregnation ratios yielded essentially mesoporous carbons with high surface area and pore volume.
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The tannins contents have been investigated in five samples of beans and the associated pulp, derived from two species of coffee and two associated hybrids. Tannins were not found in any bean sample, and in contrast to previous reports, hydrolysable tannins sensu strictu were not detected in pulp. The presence of soluble condensed tannins in Coffea arabica pulp was confirmed at approximately 1% db. Similar levels were found in pulp from Timor hybrid and Catimor, but Coffea canephora pulp yielded ≈ 2·7% db. In all cases prodelphinidins exceeded procyanidins, but the ratio varied from 2·2 to 6·0:1. Evidence was obtained also for significant amounts of insoluble condensed tannins, but reliable quantification was not possible with the analytical methods currently available.
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Biomethanation of organic waste is one of the preferred methods for producing an alternative fuel. Coffee husk, an important agro-industrial waste, resists biomethanation due to acidic pH and the presence of polyphenols. Coffee husk was treated with thermophilic fungus, Mycotypha in order to enable biomethanation. Mycotypha lowered the acidity of the husk and increased methane production. Initial gas production was delayed for 28days after which there was constant gas production till the end of the experiment. Cow dung was used as control. In two months, 5910ml of gas was produced by treated husk as against 5050ml produced by control. Combination of cow dung and Mycotypha treated husk did not yield promising result. Even though the total anaerobic microbial count was lower in treated coffee husk initially the count was comparable to that of control by 40days of fermentation. Changes in volatile fatty acid, total acidity, volatile solids and non volatile solids were comparable to control whereas total solids were much higher in treated coffee husk. Combination of treated coffee husk and cow dung did not produce any appreciable change in all the parameters analyzed. The spent obtained improved the water holding capacity of the soil and stimulated seed germination.
Article
Combustion mechanisms of two types of coffee husks have been studied using single particle combustion techniques as well as combustion in a pilot-scale fluidised bed facility (FBC), 150 mm in diameter and 9 m high. Through measurements of weight-loss and particle temperatures, the processes of drying, devolatilisation and combustion of coffee husks were studied. Axial temperature profiles in the FBC were also measured during stationary combustion conditions to analyse the location of volatile release and combustion as a function of fuel feeding mode. Finally the problems of ash sintering were analysed. The results showed that devolatilisation of coffee husks (65–72% volatile matter, raw mass) starts at a low temperature range of 170–200°C and takes place rapidly. During fuel feeding using a non water-cooled system, pyrolysis of the husks took place in the feeder tube leading to blockage and non-uniform fuel flow. Measurements of axial temperature profiles showed that during under-bed feeding, the bed and freeboard temperatures were more or less the same, whereas for over-bed feeding, freeboard temperatures were much higher, indicating significant combustion of the volatiles in the freeboard. A major problem observed during the combustion of coffee husks was ash sintering and bed agglomeration. This is due to the low melting temperature of the ash, which is attributed to the high contents of K2O (36–38%) of the coffee husks.
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The potential to remove chromium(VI) from aqueous solutions through biosorption using coffee husk was investigated. The effects of pH, contact time, initial concentration and adsorbent dosage on the adsorption of Cr(VI) were studied. The data obeyed Langmuir and Freundlich adsorption isotherms. The Langmuir adsorption capacity was found to be 44.95 mg/g. The Freundlich constants Kf and n were 1.027 (mg/g (l/mg) n ) and 1.493, respectively. Desorption studies indicated the removal of 60% of the hexavalent chromium. Infrared spectral studies revealed the presence of functional groups, such as hydroxyl and carboxyl groups, on the surface of the biomass, which facilitates biosorption of Cr(VI).
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Pellets of coffee hulls were pyrolyzed at different temperatures using microwave and electrical heating. A comparison of the gas composition obtained by both methods suggests that the different mechanisms of heating that take place in the microwave, in comparison to conventional heating, give rise to the formation of “microplasmas”, which induce self-gasification of the char that is being formed. This hypothesis was corroborated by subjecting the char to reaction with CO2 at different temperatures using both methods of heating. The results showed that, whereas the transition in the reaction mechanism controlling the Boudouard reaction (i.e., chemical or diffusional control) takes place at about 800 °C in conventional heating, in the case of microwave heating the temperature is much lower and the reaction never proceeds under pure chemical control, the differences between microwave and conventional heating being quite significant even at low temperatures.
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Fresh coffee husks, comprised of outer skin and pulp, were investigated as potential sources of anthocyanins for applications as natural food colorants. The extracted pigments were analysed by HPLC with photodiode array detection. Partial hydrolysis and analysis of the resulting fragments were helpful in the characterization procedure. Cyanidin 3-rutinoside was characterized as the dominant anthocyanin in fresh coffee husks and its quantification suggested the fresh coffee husks to be a good candidate as source of this pigment.
Article
The lignocellulosic coffee by-products such as coffee pulp, coffee cherry husk, silver skin, and spent coffee were evaluated for their efficacy as a sole carbon sources for the production of xylanase in solid-state fermentation using Penicillium sp. CFR 303. Among the residues, coffee cherry husk was observed to produce maximum xylanase activity of 9,475U/g. The process parameters such as moisture (50%), pH (5.0), temperature (30 °C), particle size (1.5mm), inoculum size (20%), fermentation time (5days), carbon source (xylose), and nitrogen source (peptone) were optimized and the enzyme activity was in the range of 19,560–20,388U/g. The enzyme production was further improved to 23,494U/g with steam as a pre-treatment. The extracellular xylanase from the fungal source was purified to homogeneity from culture supernatant by ammonium sulfate fractionation, DE32-cellulose with a recovery yield of 25.5%. It appeared as a single band on SDS-PAGE gel with a molecular mass of approximately 27kDa. It had optimum parameters of 50 °C temperature, pH 5.0, K m 5.6mg/mL, and V max 925μmolmg−1 min−1 with brichwood xylan as a substrate. The crude enzyme hydrolysed lignocellulosic substrate as well as industrial pulp. Production of xylanase utilizing coffee by-products constitutes a renewable resource and is reported for the first time. Keywords Penicillium sp. CFR 303–Xylanase–Solid-state fermentation–Coffee husk–Purification
Article
Recent interest in environment-friendly materials has led to the use of agricultural byproducts as raw material for the production of particleboards. The material used in this study are coffee husk and halls which are residues of coffee processing. Today, these materials are burnt on the field or dumped on land or in rivers. However, they contain a great amount of cellulose and hemicellulose which makes them similar to wood. The study showed that a partial replacement of wood up to 50% is possible at the production of particleboards. Depending on the type and amount of resin, the lab-made particleboards fulfil the requirements of European standards with respect to general use in dry conditions and partly in humid conditions. The results of mechanical, thermal, and hygric testing are presented. KeywordsCoffee husk and hulls-Wood-Cellulose-Particleboard-Ecology
Article
The recovery process of the phenolic compounds from the coffee industry by-products and their antioxidant activity were investigated in this work. The coffee by-products (coffee pulp, husk, silver skin, and spent coffee) were obtained from coffee processing industry. The phenolic conserves were extracted using solvent mixture of isoproponal and water. The yield of the conserve was highest in case of silver skin (25%) followed by spent waste (19%) and cherry husk (17%) when pretreated with viscozyme. The conserve enclosed chlorogenic acid as major component when analyzed with high-performance liquid chromatography. The bioactive conserves prepared from coffee by-products possessed 65%–70% antioxidant activity. Apart from these, the coffee by-products encompassed total dietary fiber of 40%–80%. Whereas the soluble and insoluble fiber proportion of the coffee by-product ranged between 16–35% and 18–64%, respectively. The antioxidant activity of coffee by-product fiber ranged from 1.5 to 2.0mmol trolox/100g and is analogous to that of widespread fruits and fresh vegetables. The hydration properties such as water holding capacity of each by-product was strictly related to the amount of insoluble fiber and to the granulometry. This is the first report on the isolation of bioactive and functional compounds from coffee by-products and can be a source of new value-added products such as phenolic antioxidant adjunct for food processing. KeywordsCoffee by-products–Chlorogenic acid–Dietary fiber–Antioxidant activity phenolic compounds
Article
Pleurotus ostreatus fungus forms an edible mushroom that possesses important nutritional and medicinal properties. Selenium (Se) is essential to human diets and it is in low concentration in the soil, and consequently in food. P. ostreatus was grown in coffee husks enriched with various concentrations of sodium selenite. The biological efficiency of P. ostreatus was affected by the addition of high concentrations of Se. The highest level of Se absorption was obtained by adding 51 mg kg1 of sodium selenite. The mushrooms from first flush contained more Se than the further flushes. These results demonstrate the great potential of coffee husks in the production of Se-enriched mushrooms and show the ability of this fungus to absorb and biomagnify Se.
Article
Caffeine is a purine alkaloid and is a major constituent of coffee, tea and other beverages. It acts as a central nervous system stimulant and also has negative withdrawal effects. Decaffeinated beverages are being used to overcome its negative effects. Decaffeination is done by different methods like solvent, water and super critical fluid extraction. These methods apart from being non-specific are expensive and involve the usage of toxic organic solvents. Development of a process involving an enzymatic (specific) degradation of caffeine to non-toxic compound is necessary to solve the problems of chemical extraction of caffeine in food products as well as treating the caffeine containing waste products. The different microbial and enzymatic methods of caffeine removal are discussed in this review. The literature revealed that major caffeine degrading strains belong to Pseudomonas and Aspergillus. Though the enzymes involved in degradation of caffeine by microorganisms are known, in vitro enzymatic studies for caffeine degradation is not yet reported.
Article
When treating municipal wastewater, the disposal of sludge is a problem of growing importance, representing up to 50% of the current operating costs of a wastewater treatment plant. Although different disposal routes are possible, anaerobic digestion plays an important role for its abilities to further transform organic matter into biogas (60–70 vol% of methane, CH4), as thereby it also reduces the amount of final sludge solids for disposal whilst destroying most of the pathogens present in the sludge and limiting odour problems associated with residual putrescible matter. Anaerobic digestion thus optimises WWTP costs, its environmental footprint and is considered a major and essential part of a modern WWTP. The potential of using the biogas as energy source has long been widely recognised and current techniques are being developed to upgrade quality and to enhance energy use. The present paper extensively reviews the principles of anaerobic digestion, the process parameters and their interaction, the design methods, the biogas utilisation, the possible problems and potential pro-active cures, and the recent developments to reduce the impact of the problems. After having reviewed the basic principles and techniques of the anaerobic digestion process, modelling concepts will be assessed to delineate the dominant parameters. Hydrolysis is recognised as rate-limiting step in the complex digestion process. The microbiology of anaerobic digestion is complex and delicate, involving several bacterial groups, each of them having their own optimum working conditions. As will be shown, these groups are sensitive to and possibly inhibited by several process parameters such as pH, alkalinity, concentration of free ammonia, hydrogen, sodium, potassium, heavy metals, volatile fatty acids and others. To accelerate the digestion and enhance the production of biogas, various pre-treatments can be used to improve the rate-limiting hydrolysis. These treatments include mechanical, thermal, chemical and biological interventions to the feedstock. All pre-treatments result in a lysis or disintegration of sludge cells, thus releasing and solubilising intracellular material into the water phase and transforming refractory organic material into biodegradable species. Possible techniques to upgrade the biogas formed by removing CO2, H2S and excess moisture will be summarised. Special attention will be paid to the problems associated with siloxanes (SX) possibly present in the sludge and biogas, together with the techniques to either reduce their concentration in sludge by preventive actions such as peroxidation, or eliminate the SX from the biogas by adsorption or other techniques. The reader will finally be guided to extensive publications concerning the operation, control, maintenance and troubleshooting of anaerobic digestion plants.
Article
This work evaluated the technical feasibility of supercritical CO2 extraction of caffeine from coffee husks, an abundant residue of the coffee industry. Different pre-treatments (initial humidity and milling) and operational conditions (pressure, temperature, time and flow rate) were studied in a CO2 continuous flow laboratory-scale unit. While prior wetting of the coffee husks was needed, milling was not required to extract the caffeine. The use of higher flow rates and/or operational times resulted in higher extraction rates. The process was favoured with increased operational pressure and temperature due to higher solubility. The maximum extraction yield obtained of this alkaloid was 84% when working at 373 K and 300 bar, using 197 kg CO2/kg husks. After water washing, the caffeine was at least 94% pure. Comparing world production data, the initial caffeine content and global extraction yield data of other natural sources, this process could be very advantageous for its technological application.