Soluble Coffee Industry Research Articles

Eye Cosmeceutical Formulations with Roasted Coffee Oil in Free and Microencapsulated Forms: Development and Preliminary Stability Study

AbstractThis research aims to develop eye cosmeceutical formulations with roasted coffee oil. Oil is used in form and microencapsulated forms. A preliminary stability study is performed, and base formulation (BF) is used for comparison. All formulations are stable and firm. Formulations with oil in free (OF) or microencapsulated (MOF) form show color and aroma of coffee. Initially, MOF is the most acid, and BF shows the highest peroxide value (PV) and the lowest sun protection factor (SPF) values and no antioxidant activity (AA). OF and MOF show AA and high SPF ; these parameters are little affected by storage, and an increase in PV is observed only for BF. Cosmeceutical formulations with roasted coffee oil present stability and good potential for dermocosmetic products.Practical Applications: Coffee oil is known for its AA and protection against sunlight UV radiation, so it fits the interest of cosmetics and personal care producers for bioactive ingredients from natural sources. The cosmetics industry uses green coffee oil; however, roasted coffee oil is of more interest since it is a coproduct of the soluble coffee industry. The authors are unaware of studies proposing the use of microcapsules (produced by complex coacervation) of roasted coffee oil in cosmeceutical formulations.

Experimental studies on mass transfer during convective drying of spent coffee grounds generated in the soluble coffee industry

Drying is a very important stage in the treatment of spent coffee grounds destined to biofuels production. The mass transfer during the convective drying of spent coffee grounds generated in the soluble coffee industry is analyzed. An experimental design from sixteen isothermal drying experiments for different sample thicknesses (5 mm, 10 mm, 15 mm and 20 mm) and drying air temperatures (100 °C, 150 °C, 200 °C and 250 °C) using a drying air velocity of 1 m s−1 was proposed. Drying times, drying rates and effective diffusivity coefficients were obtained. Drying curves were fitted with the main mathematical model proposed in the literature, and the drying rates were studied from the moisture ratio and the drying air temperature. Constant and time-dependence effective diffusivity was evaluated using polynomial surface models. Drying times range between 18 min (test at 5 mm and 250 °C) and 3 h (test at 20 mm and 100 °C). Drying rate and effective diffusivity values were found between 0.0000226 and 0.001722 s−1 and 1.79 × 10−9 and 29.1 × 10−9 m2 s−1, respectively. The main differences between these experiments and those carried out by the same authors about the drying of spent coffee grounds obtained in the services sector were studied and analyzed.

Polysaccharide-rich fraction of spent coffee grounds as promising biomaterial for films fabrication

Spent coffee grounds are wastes generated annually worldwide in significantly large amounts in the soluble coffee industry and in household and commercial beverage preparation. Although spent coffee grounds are rich in several classes of compounds, predominantly polysaccharides, profitable applications have not yet been effectively implemented for such wastes. Thus, it was the aim of this study to verify the feasibility of producing biopolymeric films from the polysaccharide-rich fraction of spent coffee grounds, obtained by alkaline hydrogen peroxide treatment of the coffee waste. Produced films were characterized for their physicochemical, barrier and mechanical properties and these properties were comparable to those of similar polysaccharides films from the literature.

Analysis of the performance of an L-valve feeding spent coffee ground powders into a circulating fluidized bed

Waste biomass powders are appealing to generate renewable energy and to reduce the dependence on fossil fuels, however, feeding reactors in processing is still a challenge. This paper examines the performance of a non-mechanical L-valve to feed dry and moist Spent Coffee Ground (SCG) powders into a circulating fluidized bed under a broad range of conveying and aeration flowrates. The L-valve performed as a robust feeder, providing stable solids circulation rate (WS) for most of the tested conditions. Solid mass flowrates were not affected by fluctuations in the riser air flowrate up to ±15%. We verified that the L-valve performance is limited by a deterioration of powders' flowability. Lower values of WS and narrower operating ranges were observed when feeding dry SCGs powders and samples containing fine particles. Nevertheless, the feeder can be considered a good option to handle SCGs with moisture content close to 30% w.b. and a mean particle size of 400 μm. This is an appealing result since the moisture content of SCGs burned in the soluble coffee industry ranges from 25 to 50%. Solids feeding was stable and operation was smooth in a range of 1.2 < WS < 10.0 g/s. Finally, a correlation to predict Ws from the pressure drop in the L-valve is proposed, which fitted our data better than other equations available in the literature.

Thermoeconomic analysis for a trigeneration system in a soluble coffee industry

Considering that a trigeneration system tends to result in higher thermal efficiency than electricity, heating and cooling generation in separated ways, the purpose of this study is to perform a thermoeconomic analysis of a trigeneration system in a soluble coffee industry in order to improve its energy and economic performance. The current thermal system has a steam generator that provides heating utility for the soluble coffee production, including a refrigeration plant using ammonia/water absorption, while the electricity is bought from the energy concessionary. The proposal is to include an extraction-condensing steam turbine providing 5100 kW of electricity to the industrial plant, besides keeping the same energy demands in the current plant. Heat, cold and power were evaluated for their costs per unit of exergy in the current plant and compared to the proposal of the trigeneration system. The results show that the proposal to integrate a turbo-generator is technically and economically viable, resulting in reduction in the costs for heating, cooling and electricity of up to 72% in a payback period of only 24 months.

Production and Characterization of the Bio-Oil Obtained by the Fast Pyrolysis of Spent Coffee Grounds of the Soluble Coffee Industry

Agro-industrial wastes are abundant and low-cost sources of energy and chemicals. Biomass account for 14% of the world’s energy production. Industrial residues of production of soluble coffee (spent coffee grounds - SCG) have great potential due to its large-scale production and can be transformed by pyrolysis, in liquid, solid and gaseous products with applications from energy to chemicals. This work has the objective of producing bio-oil from the pyrolysis of industrial SCG, characterize it by chromatography and indicate its possible applications. As SGC contains a large amount of glycerides, they were extracted from SGC before the pyrolysis, aiming to obtain a better bio-oil from the residue. The yield in vegetable oil was 5.2% and its analyses showed that 50% are saturated acids (mainly palmitic 27.6%) and other 50% are unsaturated ones (mainly linoleic acid 35.3%). This composition qualifies this oil for biodiesel purposes. The residue (SGC after extraction) was submitted to pyrolysis, yielding 30% in liquid products, being 6% bio-oil. The bio-oil was analyzed by gas chromatography being identified free fatty acids, hydrocarbons, phenols and N-compounds. The heteroatomic compounds limit the use as biofuel but can be interesting for the pharmaceutical, agrochemical and fine chemicals industries.

Spent coffee grounds as a renewable source of energy: An analysis of bulk powder flowability

The main use for spent coffee grounds (SCG) produced in the soluble coffee industry is thermal energy generation in the industry itself. The SCG are processed using operations that are strongly dependent on powder flow behavior. In this study, we evaluated two classical flowability indices of non-consolidated SCG powders: the angle of repose (AoR), and the Hausner ratio (HR). The influences of the mean particle diameter, particle size distribution (PSD), and water content on the AoR and HR values of SCG were analyzed for powders with a mean particle size range of 225–550μm. For powders with a mean particle size close to 350μm and for mixtures containing more than 40% fine particles, the HR (>1.35) and AoR (>45°) values were characteristic of poor flowability. The AoR was sensitive to the powder PSD, and powders with similar mean particle sizes had higher AoR values when the PSD was larger. For powders with water contents up to 50%, the flowability indices were not greatly affected by the water content. A modified linear-mixture packing model was used to predict the packed bed void fractions for binary and ternary mixtures of the three base powders. The model was used to construct a ternary diagram to estimate the HR values of the mixtures. An equation was fitted to correlate HR and AoR. The proposed diagram and the equation provide insight into flow behavior and could be used for process design of industrial plants that handle SCG.

Performance and emissions characteristics of compressed spent coffee ground/wood chip logs in a residential stove

Spent coffee grounds (SCG), a processing by-product from the soluble coffee industry, was evaluated as a potential feedstock for preparing compressed logs for energy production. Hence, a blend of SCG/wood chips was transformed into densified logs using an industrial press. Chemical properties such as calorific value, ash content and elemental analysis were obtained. Combustion tests were carried out with a five-star–labeled stove in a French industrial research and development laboratory. Three different configurations were tested: a densified log containing 20wt% of SCG blended with pine wood chips, another containing a mixture 50/50wt% of SCG/pine wood chips and a classical beech log. This study is the first one that focuses on the potential of compressed logs as a new biocombustible for wood stoves. The obtained results show that the combustion of logs containing SCG leads to better yield of combustion. Nevertheless, CO and particle emissions increase when increasing the rate of SCG although the exhaust gas emissions and combustion yields always lead to the “five-star Flamme Verte” label achievement. Such attainment is essential to sell these densified biofuel logs in the French market. Results indicate that the blended densified logs are combusted rapidly leading to higher stove efficiency and therefore good heat recuperation from the stove walls. On the contrary, the addition of SCG leads to lower CO2 concentrations (7.7% and 9.05% for 20wt% and 10wt% of SCG, respectively). This behavior indicates that the combustion of compressed logs is not suitable for the stove design and may lead to an uncomfortable heating. One should be reminded that the evaluated stove was designed for the combustion of conventional wood logs (with respect to the NF Bois de Chauffage standard). This means that the results obtained during this study with the different densified fuel logs could be improved after an adjustment of the stove conception.

Utilização de Resíduos de Borra de Café e Serragem na Moldagem de Briquetes e Avaliação de Propriedades

Este trabalho envolveu a moldagem de briquetes com utilização de resíduos de pó borra de café e serragem de madeira de eucalipto. Os briquetes produzidos a partir de biomassa vegetal podem ser aplicados como substituintes de outros combustíveis utilizados em caldeiras de processos industriais ou até mesmo para aquecimento de residências, em regiões frias, com utilização de equipamentos mais simples. No Brasil e em muitos países uma grande quantidade de resíduos de borra de café é produzida e desperdiçada no cotidiano e em indústrias de café solúvel. A serragem de madeira também é um resíduo bastante comum no Brasil, principalmente, em algumas cidades que concentram grande número de empresas que processam madeira. Assim, a moldagem de briquetes com estes resíduos sólidos é uma oportunidade de reaproveitar os resíduos para produzir um tipo de combustível proveniente de fonte renovável, contemplando também aspectos relacionados à bioenergia e Produção Mais Limpa (P+L). Desta forma, no presente trabalho foram realizadas moldagens de briquetes utilizando o pó da borra de café e serragem de madeira em diferentes proporções destes materiais para avaliar propriedades mecânicas de compressão diametral. Também foram realizadas análises para determinar os teores de umidade, voláteis e cinzas, além da determinação do poder calorífico superior (PCS). Todas as composições de briquetes contendo serragem ocasionaram acréscimos nos valores das médias das propriedades de resistência máxima à compressão diametral e módulo de elasticidade, quando comparados aos valores destas propriedades dos briquetes moldados apenas com a borra de café. As diferentes composições de briquetes contendo serragem apresentaram valores próximos de resistência à compressão diametral. Considerando os valores do poder calorífico (PCS), todas as amostras apresentaram resultados semelhantes em comparação com a literatura. Os briquetes contendo somente borra de café na composição apresentaram resultados de teores de cinzas, voláteis e PCS similares aos das amostras contendo serragem. Porém, os briquetes contendo somente borra de café apresentaram valores inferiores de resistência máxima à compressão quando comparados a todos os outros briquetes moldados também com serragem.

The chemical composition of exhausted coffee waste

The chemical composition of exhausted coffee waste generated in a soluble coffee industry was investigated. The chemical characterization included elemental analysis, mineral composition and ash content, summative composition; acidic functional groups, lipophilic extractives, total polyphenols, condensed tannins determination and FTIR analysis. The spent coffee samples showed high carbon (>58%), low nitrogen (<2%), and low ash (<1%) contents and low polarity coefficient (O+N)/C (<0.5). The summative composition reveals that extractives are the main components of exhausted coffee wastes (54%). This percentage includes lipophilic fractions (24%), ethanol and water soluble compounds (5%), and compounds solubilized in 1% NaOH (26%). Lignin and polysaccharides were found in a similar proportion between 20 and 26%. The GC analysis of monosaccharide showed about 60% glucose and 40% mannose. The main components in the lipophilic extractives are free fatty acids (>60%) of which more than 30% was identified to be n-hexadecanoic acid. Total polyphenols and tannins represent <6% and <4% of the exhausted coffee wastes, respectively. Assignments of the bands of the obtained FTIR spectra confirm the presence of lipids, polysaccharides and chlorogenic acid. Exhausted coffee wastes showed characteristics for various potential applications such as biodiesel production, as a source of antioxidants and as a biosorbent of hydrophobic pollutants.

Spent Coffee Grounds as a Renewable Source of Bioactive Compounds

Spent coffee grounds (SCG) are the main residues from the soluble coffee industry. The objective of this work was to evaluate different extraction methods of oil and diterpenes (kahweol and cafestol) from SCG, such as solid–liquid extraction, supercritical extraction or direct saponification, as well as to determine the phenolic composition and antioxidant capacities (by radical scavenging activity, inhibition of linoleic acid oxidation and -carotene bleaching method) of SCG and defatted SCG. Among assayed oil extraction methods, the Soxhlet extraction process recovered the highest oil amounts (26.4%). The free fatty acid profile showed a high content of polyunsaturated fatty acids (50%) for the lipid fraction extracted from SCG by each method used, mainly linoleic and palmitic acids (about 45 and 30%, respectively). SCG was found to be an important source of polyphenolic compounds, showing 255 and 273 mg GAE/g dm in ethanolic extracts from SCG and defatted SCG, respectively, and was active as an antioxidant. The method that reached the highest level of diterpenes (214 mg/100 g SCG for kahweol and 466 mg/100 g SCG for cafestol) was direct saponification compared with the saponification of oil extracted by solid–liquid extraction or supercritical extraction. Finally, the presence of bioactive compounds of SCG identified in this study could be of great interest for the food, cosmetic and pharmaceutical industries, giving added value to a residue generated from instant coffee industrial processing, readily available in large quantities.

Effect of temperature on thermochemical property and true density of torrefied coffee residue

Torrefaction is a mild pyrolysis process in the relatively low temperature, which aims to upgrade the thermochemical and physical properties of biomass as a high energy-density fuel. In this study, coffee residue, a processing by-product from the soluble coffee industry, was torrefied at the temperature range of 503–623K with residence time of 10min by a commercial electric oven. The thermochemical properties of the torrefied biomass, such as elemental analysis and calorific value, were investigated. Furthermore, the information about microscopic and structural characteristics was also obtained by means of scanning electron microscopy (SEM) and true density. It was found that the calorific value of the torrefied biomass increased with temperature, while its maximal increase occurred at around 563K. This result was in high agreement with the observation from the thermogravimetric analysis (TGA) of coffee residue. More consistently, the carbon content of torrefied coffee residue increased significantly as temperature increased from 563 to 593K, which should be the temperature window of torrefaction for this biomass. By contrast, the contents of hydrogen and oxygen decreased slightly due to the devolatilization as a result of thermal decomposition reactions like dehydration and depolymerization. On the other hand, the true density of torrefied coffee residue increased with temperature at above 563K, making it more observable in the structural shrinkage as also depicted in the SEM. However, it may involve light gases released and loose structure remained at temperature of below 563K, leading to decreased true density with temperature from 503 to 563K.

Espresso Coffee Residues: A Valuable Source of Unextracted Compounds

Espresso spent coffee grounds were chemically characterized to predict their potential, as a source of bioactive compounds, by comparison with the ones from the soluble coffee industry. Sampling included a total of 50 samples from 14 trademarks, collected in several coffee shops and prepared with distinct coffee machines. A high compositional variability was verified, particularly with regard to such water-soluble components as caffeine, total chlorogenic acids (CGA), and minerals, supported by strong positive correlations with total soluble solids retained. This is a direct consequence of the reduced extraction efficiency during espresso coffee preparation, leaving a significant pool of bioactivity retained in the extracted grounds. Besides the lipid (12.5%) and nitrogen (2.3%) contents, similar to those of industrial coffee residues, the CGA content (478.9 mg/100 g), for its antioxidant capacity, and its caffeine content (452.6 mg/100 g), due to its extensive use in the food and pharmaceutical industries, justify the selective assembly of this residue for subsequent use.

Preparation and fuel properties of biochars from the pyrolysis of exhausted coffee residue

Exhausted coffee residue (ECR), a processing by-product from the soluble coffee industry, was evaluated as a potential feedstock for preparing biochar fuel. Its thermochemical characteristics were first investigated using the standard methods, showing that the biomass obviously comprises a large percentage of volatile matter and less amount of ash. Its molar ratio of hydrogen to carbon (H/C) is about 1.59, which is close to the cellulose (H/C = 1.67) and hemicellulose (H/C = 1.60). Under the pyrolysis temperature of 673–973 K and the heating rate of about 10 K/min studied, the yields and calorific values for the resulting biochar products reached to the maximum at the condition of around 673 K. The calorific value (around 31.9 MJ/kg) of the optimal biochar from ECR was relatively high as compared to that of coal. However, the resulting biochar has greater nitrogen content, which may contribute to greater nitrogen oxides (NO x ) emissions during combustion or co-firing. On the other hand, the resulting biochars were characterized using helium-based solid density (true density), showing that the density increased with increasing pyrolysis temperature in accord with the conversion of low-density disordered carbon to high-density turbostratic carbon.

Kinetics and equilibrium studies of methylene blue adsorption by spent coffee grounds

Spent coffee grounds (SCG), a residue from the soluble coffee industry, was evaluated as an adsorbent for the removal of methylene blue (MB) from aqueous solution. Batch adsorption tests were performed at 25 °C and the effects of contact time, adsorbent dosage, and pH were investigated. Adsorption kinetics was determined by fitting first and second-order kinetic models to the experimental data, with the second-order model providing the best description of MB adsorption onto spent coffee grounds. The typical dependence of dye uptake on kinetic studies indicated the adsorption process to be both chemisorption and diffusion controlled. The experimental adsorption equilibrium data were fitted to Langmuir, Freundlich and Tempkin adsorption models. The experimental data obtained in the present study indicate that spent coffee grounds are suitable candidates for use as adsorbents in the removal of cationic dyes.

Production, partial purification and properties of β‐mannanases obtained by solid substrate fermentation of spent soluble coffee wastes and copra paste using Aspergillus oryzae and Aspergillus niger

In order to achieve a higher added value of two galactomannan-containing wastes, copra paste and spent coffee from the soluble coffee industry (SCW), solid substrate fermentation (SSF) was used. Filamentous fungi Aspergillus oryzae and A niger were used to evaluate the feasibility of producing β-mannanase by SSF. A 23 factorial design was used to select the best interaction among the two fungi, the two substrates and two fermentation times. The treatment ‘A niger–copra–2.5 days’ produced a significantly higher (p < 0.05) β-mannanase activity, having five different isoforms of the enzyme, one of which was partially purified to a specific activity of 764 U mg−1 (U = nmol of mannose released per second from a galactomannan substrate). Copra paste had a higher mannose/galactose ratio (14:1) than SCW (6:1), and low oil content, which led to higher β-mannanase production from SSF. A β-mannanase from SSF of copra produced by A oryzae was highly purified using acetone precipitation and cation exchange and size exclusion chromatographies. This enzyme had an MW of 110 kDa, a pI between 3.5 and 4.5 and a specific activity of 1760 U mg−1; purification achieved was 90.7 times. The temperature and pH for optimal activity were 40 °C and 6.0 respectively. The optimal temperature was lower and the optimal pH higher than others previously reported (produced by submerged fermentation), which could be important for viscosity reduction of concentrated coffee extract in instant coffee manufacture. Copra is an interesting alternative for β-mannanase production, since it is readily available in Mexico; moreover, the residue after SSF has a reduced galactomannan content and may be used for monogastric animal feed. © 2000 Society of Chemical Industry

99/01367 The use of biomass residues in the Brazilian soluble coffee industry : Silva, M. A. et al. Biomass Bioenergy, 1998, 14, (5–6), 457–467

99/01367 The use of biomass residues in the Brazilian soluble coffee industry : Silva, M. A. et al. Biomass Bioenergy, 1998, 14, (5–6), 457–467

THE USE OF BIOMASS RESIDUES IN THE BRAZILIAN SOLUBLE COFFEE INDUSTRY

The objective of this paper is to discuss the use of coffee grounds in the Brazilian soluble coffee industry. This residue is used as a fuel in the boilers of the same industry; so, data about their utilization are presented and analysed, discussing the actual technology and the advantages of improving the drying of the biomass with the exhaust combustion gases. After that, an experimental study is reported on the characteristics of this material, which are important for the combustion process, including the transport, storage and drying, the mean diameter of the particles, talus angle, apparent and real density, sphericity, surface area, terminal velocity, spontaneous ignition temperature and heat of combustion.

The distribution of solar radiation throughout southern Africa : Drummond, A. J. and Vowinckel, E., J. Meteor. 14 (4): 343-53, Aug. 1957. Illus.

Spent coffee grounds (SCG), a processing by-product from the soluble coffee industry, was evaluated as a potential feedstock for preparing compressed logs for energy production. Hence, a blend of SCG/wood chips was transformed into densified logs using an industrial press. Chemical properties such as calorific value, ash content and elemental analysis were obtained. Combustion tests were carried out with a five-star–labeled stove in a French industrial research and development laboratory. Three different configurations were tested: a densified log containing 20 wt% of SCG blended with pine wood chips, another containing a mixture 50/50 wt% of SCG/pine wood chips and a classical beech log. This study is the first one that focuses on the potential of compressed logs as a new biocombustible for wood stoves. The obtained results show that the combustion of logs containing SCG leads to better yield of combustion. Nevertheless, CO and particle emissions increase when increasing the rate of SCG although the exhaust gas emissions and combustion yields always lead to the “five-star Flamme Verte” label achievement. Such attainment is essential to sell these densified biofuel logs in the French market. Results indicate that the blended densified logs are combusted rapidly leading to higher stove efficiency and therefore good heat recuperation from the stove walls. On the contrary, the addition of SCG leads to lower CO2 concentrations (7.7% and 9.05% for 20 wt% and 10 wt% of SCG, respectively). This behavior indicates that the combustion of compressed logs is not suitable for the stove design and may lead to an uncomfortable heating. One should be reminded that the evaluated stove was designed for the combustion of conventional wood logs (with respect to the NF Bois de Chauffage standard). This means that the results obtained during this study with the different densified fuel logs could be improved after an adjustment of the stove conception.

Temperature consideration in solar battery development : Halsted, R. E., J. App. Phys. 28 (10): 1131, Oct. 1957. Illus.

Spent coffee grounds (SCG), a processing by-product from the soluble coffee industry, was evaluated as a potential feedstock for preparing compressed logs for energy production. Hence, a blend of SCG/wood chips was transformed into densified logs using an industrial press. Chemical properties such as calorific value, ash content and elemental analysis were obtained. Combustion tests were carried out with a five-star–labeled stove in a French industrial research and development laboratory. Three different configurations were tested: a densified log containing 20 wt% of SCG blended with pine wood chips, another containing a mixture 50/50 wt% of SCG/pine wood chips and a classical beech log. This study is the first one that focuses on the potential of compressed logs as a new biocombustible for wood stoves. The obtained results show that the combustion of logs containing SCG leads to better yield of combustion. Nevertheless, CO and particle emissions increase when increasing the rate of SCG although the exhaust gas emissions and combustion yields always lead to the “five-star Flamme Verte” label achievement. Such attainment is essential to sell these densified biofuel logs in the French market. Results indicate that the blended densified logs are combusted rapidly leading to higher stove efficiency and therefore good heat recuperation from the stove walls. On the contrary, the addition of SCG leads to lower CO2 concentrations (7.7% and 9.05% for 20 wt% and 10 wt% of SCG, respectively). This behavior indicates that the combustion of compressed logs is not suitable for the stove design and may lead to an uncomfortable heating. One should be reminded that the evaluated stove was designed for the combustion of conventional wood logs (with respect to the NF Bois de Chauffage standard). This means that the results obtained during this study with the different densified fuel logs could be improved after an adjustment of the stove conception.