Coffee Grounds Oil Research Articles

Innovative application of coffee grounds oil as an asphalt modifier: Extraction, preparation, and rheological properties

This study innovatively utilized coffee grounds oil (CGO) extracted from waste coffee grounds to modify base asphalt, aiming to promote sustainable reuse of coffee waste. The effects of modifier dosage, type, and aging conditions on the rheological properties of asphalt were investigated. After determining the extraction protocol, coffee grounds oil-modified asphalt (CGOA) and waste cooking oil-modified asphalt (WCOA) were prepared and subjected to short-term aging. Fourier transform infrared spectroscopy (FTIR) analyzed the modification mechanism, while temperature sweep, frequency sweep, bending beam rheometer, and multiple stress creep recovery (MSCR) tests assessed the rheological properties at high and low temperatures. Results showed that before aging, CGO improved thermal stability at medium to high temperatures and enhanced deformation and stress relaxation at low temperatures, though it reduced rutting resistance at high temperatures. After aging, CGOA with a dosage limited to 4 % exhibited rheological properties approaching base asphalt and improved the viscoelasticity of aged asphalt. In comparison, WCOA demonstrated significantly weaker performance, particularly after aging. This study provides practical insights into the novel application of CGO in pavement engineering.

Effect of gamma irradiation in the coffee grounds oil and kernel mango fat properties

Effect of gamma irradiation in the coffee grounds oil and kernel mango fat properties

Characteristics of Arabica and Robusta Spent Coffee Grounds Oil Extract with Different Solvents

Abstract High coffee consumption contributes to waste, such as spent coffee grounds (SCG). SCG contains up to 20 % oil, with the main oil content being linoleic and palmitic fatty acids. So, SCG has the potential to be used in valuable products. This study aims to characterise Arabica and Robusta SCG oil using maceration methods with different solvents (hexane, ethanol, and petroleum benzene) to obtain maximum coffee oil as an alternative. Arabica and Robusta SCG characterisation comprises the composition content, oil yield, fatty acid profile, and viscosity. The results showed that Arabica SCG oil yield was higher than Robusta, with hexane becoming the most efficient solvent to extract the oil, with 28,87% and 25,57%, respectively. The lowest free fatty acid (FFA) found in Arabica SCG oil extract using hexane is 1,95%, which consists of palmitic acid (9.41%), linoleic acid (5.37%), and stearic acid (4.7%). The highest viscosity is Arabica SCG oil extract using hexane, which is caused by the large amount of long-chain fatty acids extracted by the solvent, such as palmitic acid and linoleic acid. The FFA content of Arabica SCG oil extract using hexane has the potential to be edible oil (cooking oil) and biodiesel.

Biodiesel production from spent coffee grounds utilizing pomegranate/orange peel biochar as a green and renewable nanocatalyst: Compression ignition engine performance and emission

In this research, a novel pomegranate/orange peel-derived activated carbon (POPAC) green heterogeneous nanocatalyst was developed for the conversion of spent coffee grounds oil (SCGO) into biodiesel by ultrasonication and its application in diesel engine characteristics. The surface and texture attributes of the POPAC green nanocatalyst were scrutinized employing SEM, EDX, CO2-TPD, XRD, TEM, FTIR, Raman, and BET. Based on the response surface methodology (RSM) outcomes, the highest biodiesel efficiency employing POPAC green nanocatalysts was 95.24 %, which was attained at optimal conditions (i.e., molar proportion of 11.02, nanocatalyst content of 2.56 wt%, ultrasonic time of 30.77 min, and temperature of 60 0C). Moreover, the stability assessment demonstrated the high reusability of POPAC green nanocatalysts, with biodiesel efficiency remaining at 87.43 % even after the 7th round. Further, the kinetic survey exhibited that the biodiesel synthesis is endothermic and the conversion rate is enhanced by boosting the temperature. Besides, the impact of merging biodiesel with the diesel/biodiesel combination at diverse torques was scrutinized on the emission of exhaust output (e.g., UHC, NOx, CO, and CO2) and engine crucial characteristics (i.e., BP, EGT, BTE, and BSFC), and encouraging results were acquired. Briefly, due to special attributes including high catalytic performance, substantial recyclability, and eco-friendliness, POPAC green nanocatalyst are highly suggested for biodiesel generation.

Ester Production Using the Lipid Composition of Coffee Ground Oil (Coffea arabica): A Theoretical Study of Eversa® Transform 2.0 Lipase as an Enzymatic Biocatalyst

The scientific community recognizes coffee grounds (Coffea arabica) as an important biological residue, which led to using the Eversa® Transform 2.0 lipase as an in silico enzymatic catalyst for coffee grounds’ free fatty acids (FFA). Molecular modeling studies, including molecular docking, were performed, which revealed the structures of the lipase and showed the primary interactions between the ligands and the amino acid residues in the active site of the enzyme. Of the ligands tested, 6,9-methyl octadienoate had the best free energy of −6.1 kcal/mol, while methyl octadecenoate and methyl eicosanoate had energies of −5.7 kcal/mol. Molecular dynamics confirmed the stability of the bonds with low Root Mean Square Deviation (RMSD) values. The MMGBSA study showed that methyl octadecenoate had the best free energy estimate, and CASTp identified key active sites for potential enzyme immobilization in experimental studies. Overall, this study provides efficient and promising results for future experimental investigations, showing a classification of oils present in coffee grounds and their binding affinity with Eversa.

Edible/Biodegradable Packaging with the Addition of Spent Coffee Grounds Oil.

Following petroleum, coffee ranks as the second most extensively exchanged commodity worldwide. The definition of spent coffee ground (SCG) can be outlined as the waste generated after consuming coffee. The aims of the study are to produce edible/biodegradable packaging with the addition of spent coffee grounds (SCG) oil and to investigate how this fortification can affect chemical, textural, and solubility properties of experimentally produced films. The produced films were based on κ-carrageenan and pouring-drying techniques in petri dishes. Two types of emulsifiers were used: Tween 20 and Tween 80. The films were analyzed by antioxidant and textural analysis, and their solubility was also tested. Edible/biodegradable packaging samples produced with the addition of SCG oil showed higher (p < 0.05) antioxidant capacity in comparison with control samples produced without the addition of SCG oil. The results of the research showed that the fortification of edible/biodegradable packaging with the addition of SCG oil changed significantly (p < 0.05) both chemical and physical properties of the films. Based on the findings obtained, it was indicated that films manufactured utilizing SCG oil possess considerable potential to serve as an effective and promising material for active food packaging purposes.

Moving towards green lubrication: tribological behavior and chemical characterization of spent coffee grounds oil

ABSTRACT With the EU aiming for net-zero greenhouse gas emissions by 2050, conventional production cycles must be transformed into cradle-to-cradle approaches. Spent coffee grounds are often dumped in landfills, with their potential as high-quality feedstock for biofuel or bio-lubricant production. Spent coffee grounds oil (SCGO) was investigated for its physicochemical properties while having more free acid groups compared to the reference polyalphaolefin 8 (PAO 8), which may cause faster oxidation. TGA results displayed comparable thermal stability of SCGO and PAO 8 for inert/oxidative atmosphere. The oil composition was characterized by ATR-FTIR, elemental analysis, and GC-EI-MS, where a higher oxygen content was found for SCGO, referring to functional ester/acid groups. The tribological behavior of SCGO was studied as lubricant base oil and as a 5% additive in PAO 8. The condition of fresh and tribologically used oils was investigated with High-Resolution-ESI-MS, and the worn surfaces were evaluated by light microscopy and topographic analysis. The results showed a superior friction coefficient of pure SCGO (µ = 0.092) to PAO 8 (µ = 0.129). The 5% SCGO additive in PAO 8 (µ = 0.095) could significantly reduce friction compared to pure PAO 8 on an unpolished 100Cr6 surface.

Influence of the Solvent on the Extraction of Phenolic Com-pounds from the Coffee Grounds by Soxhlet Leaching

In this study, phenolic compounds were extracted from the essential oil of coffee grounds originated in the coffee industry in the city of Guayaquil, Ecuador. The selected method was Soxhlet leaching, with three types of solvents (methanol, ethanol, and hexane), in its conventional form (solid-liquid), with two polar solvents and one nonpolar solvent, and in four extraction periods (30, 60, 90, and 120 minutes). The highest phenolic concentration and the best associative capacity were obtained with ethanol as the solvent for extraction, while the use of methanol yielded the second-best results. The extraction performance regarding the coffee grounds oil obtained higher results when using methanol, but close values were obtained with ethanol. Methanolic extracts obtained from coffee grounds can cause the formation of undesirable substances and be responsible for the methanolysis of gallic depsides. Therefore, the solvent-assisted technique depends on the selectivity and affinity of the compounds, according to their polar covalent character, the molecular geometry of the solvent, its relationship with its dielectric constant, and the null generation of unwanted reactions during extraction.

Performance of alcoholic solvents in the continuous countercurrent spent coffee grounds oil extraction

Ethanol and isopropanol, absolute (ET0, IPA0) and hydrated with 6 and 12 water mass% (ET6, IPA12), were evaluated as solvents in the oil extraction from spent coffee grounds (SCGO). Alcohols' performance evaluation was based on the SCGO partitioning between extract and raffinate phases and the extractor design. An SCGO concentration limit in systems containing ET indicates extract phase saturation. In this case, a Langmuir-type equation provided a satisfactory SCGO partitioning data mathematical description, while the IPA data presented a linear behavior. The increase in temperature from 60 to 80 °C did not affect SCGO partitioning when IPA0 was used as a solvent. ET6 required higher solvent proportions concerning SCG, leading to extractors with a higher number of theoretical stages. The minimum flow rates of ET6 were 1.9 times higher than those required by ET0 and IPA12 and up to 3.2 times higher than the IPA0 flow rate at 60 °C. At 80 °C, the SCGO extraction performance with ET0 and IPA0 was similar. A solvent-to-feed ratio of at least five must be used when an extractor with five theoretical stages operating at 80 °C is considered. In this case, extracts with about 5 mass% of SCGO are obtained.

Optimized cell growth and poly(3-hydroxybutyrate) synthesis from saponified spent coffee grounds oil

Spent coffee ground (SCG) oil is an ideal substrate for the biosynthesis of polyhydroxyalkanoates (PHAs) by Cupriavidus necator. The immiscibility of lipids with water limits their bioavailability, but this can be resolved by saponifying the oil with potassium hydroxide to form water-soluble fatty acid potassium salts and glycerol. Total saponification was achieved with 0.5 mol/L of KOH at 50 °C for 90 min. The relationship between the initial carbon substrate concentration (C0) and the specific growth rate (µ) of C. necator DSM 545 was evaluated in shake flask cultivations; crude and saponified SCG oils were supplied at matching initial carbon concentrations (C0 = 2.9–23.0 g/L). The Han-Levenspiel model provided the closest fit to the experimental data and accurately described complete growth inhibition at 32.9 g/L (C0 = 19.1 g/L) saponified SCG oil. Peak µ-values of 0.139 h−1 and 0.145 h−1 were obtained with 11.99 g/L crude and 17.40 g/L saponified SCG oil, respectively. Further improvement to biomass production was achieved by mixing the crude and saponified substrates together in a carbon ratio of 75:25% (w/w), respectively. In bioreactors, C. necator initially grew faster on the mixed substrates (µ = 0.35 h−1) than on the crude SCG oil (µ = 0.23 h−1). After harvesting, cells grown on crude SCG oil obtained a total biomass concentration of 7.8 g/L and contained 77.8% (w/w) PHA, whereas cells grown on the mixed substrates produced 8.5 g/L of total biomass and accumulated 84.4% (w/w) of PHA.Key points• The bioavailability of plant oil substrates can be improved via saponification.• Cell growth and inhibition were accurately described by the Han-Levenpsiel model.• Mixing crude and saponified oils enable variation of free fatty acid content.

Spent coffee ground oil as a valuable source of epoxides and epoxidation derivatives: Quantitation and characterization using low-field NMR

Coffee waste, commonly referred to as spent coffee grounds (SCG), is currently discarded and has a negative impact on the environment. However, SCG are rich in valuable ingredients including 15–20% oil, which has a profile comparable to the vegetable oils used in the production of epoxides, biobased polyols, and polymers. Our first objective was to evaluate the efficiency of three different methods, namely Soxhlet, pressurized fluid extraction, and supercritical CO2 (scCO2) on SCG oil extraction. Additionally, we aimed to test the potential of low-field (LF) NMR to analyze SCG oil and monitor the formation of epoxides and biobased polyols. Finally, we evaluated epoxidized SCG oil as a plasticizer for improving the properties of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) bioplastic. Overall, SCG showed a promising potential as a source of biopolymer precursors, while LF NMR can be an efficient and economic tool for oil evaluation and reaction monitoring.

Emerging potential of spent coffee ground valorization for fuel pellet production in a biorefinery.

The global market for fuel pellets (FPs) has been steadily growing because of a shift to coal substitutes. However, sustainability and the availability of biomass are the main issues. Various kinds of bio-wastes can be valorized through cutting-edge technologies. In the coffee industry, a valuable organic waste called spent coffee grounds (SCGs) is generated in bulk. SCG can be divided into two components, namely spent coffee ground oil and defatted spent coffee grounds (DSCG). SCG and DSCG can be used to produce FPs with excellent higher heating values. This review highlights that burning FPs composed of 100% SCG is not feasible due to the high emission of NOx. Moreover, the combustion is accompanied by a rapid temperature drop due to incomplete combustion which leads to lower boiler combustion efficiencies and increased carbon monoxide emissions. This was because of the low pellet strength and bulk density of the FP. Mixing SCG with other biomass offers improved boiler efficiency and emissions. Some of the reported optimized FPs include 75% SCG + 20% coffee silverskin, 30% SCG + 70% pine sawdust, 90% SCG + 10% crude glycerol, 32% SCG + 23% coal fines + 11% sawdust + 18% mielie husks + 10% waste paper + 6% paper pulp, and 50% SCG + 50% pine sawdust. This review noted the absence of combustion and emissions analyses of DSCG and the need for their future assessment. Valorization of DSCG offers a good pathway to improve the economics of an SCG-based biorefinery where the extracted SCGO can be valorized in other applications. The combustion and emissions of DSCG were not previously reported in detail. Therefore, future investigation of DSCG in boilers is essential to assess the potential of this industry and improve its economics.Graphical abstract Supplementary InformationThe online version contains supplementary material available at 10.1007/s10668-022-02361-z.

Evaluation of Techniques for Intensifying the Process of the Alcoholic Extraction of Coffee Ground Oil Using Ultrasound and a Pressurized Solvent.

Ultrasound-assisted extraction (UAE) and pressurized liquid extraction (PLE) techniques were evaluated and compared with conventional extraction for obtaining spent coffee ground oil (SCGO). The use of absolute ethanol (ET0) and hydrated ethanol (ET6) as solvents, two levels of SCG mass ratio:solvent, 1:4 (U4) and 1:15 (U15), and ultrasound powers of 0, 200, 400, and 600 W were tested. ET0 and U15 resulted in higher extraction yields of SCGO (YSCGO, 82%). A positive effect of sonication on YSCGO was observed only for condition U4. UAE resulted in defatted solids (DS) with higher apparent density values, corroborating the increase in the amount of smaller diameter particles due to sonication. The micrographs showed changes in the surfaces of the solids from the UAE and PLE, although the crystalline structures of the DS were not altered. UAE and PLE, compared to conventional extraction, did not allow significant gains in terms of YSCGO and, consequently, in the number of contact stages in an extractor configured in cross-currents.

Optimization of Ultrasound-Assisted Extraction of Spent Coffee Grounds Oil Using Response Surface Methodology

Spent coffee grounds (SCGs) generated in coffee processing for beverages and other products are a very significant organic residue that needs to be properly treated. Waste valorization via oil extraction has the potential to obtain compounds that can be used for producing biodiesel or other high-value products, such as polymers. This work focuses on the ultrasound-assisted extraction of SCG oil using n-hexane as a solvent. Three key process parameters are analyzed: temperature, extraction time, and liquid/solid (L/S) rate of solvent, using a central composite rotatable design (CCRD), an analysis that, to the author’s knowledge, is not yet available in the literature. The data were analyzed using the software StatSoft STATISTICA 13.1 (TIBCO Software Inc., Palo Alto, CA, USA). Results show that all parameters have a statistical influence on the process performance (p &lt; 0.05), being the L/S ratio the most significant, followed by extraction time and temperature. An analysis of variance (ANOVA) showed that the empirical model is a good fit to the experimental data at a 95% confidence level. For the range of conditions considered in this work, the optimal operating conditions for obtaining an oil extraction yield in the range of 12 to 13%wt are a solvent L/S ratio of around 16 mL g−1, for a temperature in the range of 50 to 60 °C, and the longest contact time, limited by the process economics and health and safety issues and also, by the n-hexane boiling temperature.

Spent Coffee Ground Oil as a Potential Alternative for Vegetable Oil Production: Evidence from Oil Content, Lipid Profiling, and Physicochemical Characterization

In this work, routinely measured physicochemical indices and lipid profiling of oil extracted from spent coffee grounds (SCG) were evaluated to assess the suitability of SCG as a new candidate for oil production. The obtained results reveal that the oil yield was 18.55±1.5 g/100g. Physicochemical indices were comparable to those of widely consumed vegetable oils in the range set in several studies. The main fatty acids of SCG oil were linoleic acid 43.20±2.19 g/100g, palmitic acid 31.78±2.02 g/100g, and oleic acid 12.68±1.15 g/100g dry basis. For sterol composition, β-sitosterol was the most abundant sterol (44.70±0.01%), followed by stigmasterol (27.57±0.01%) and campesterol (12.16±0.01%). In conclusion, this composition is typical for many other vegetable oils. Therefore, this oil may be considered a good alternative for vegetable oil production for new multi-purpose products such as cosmetic and industrial pharmaceutical uses.

POLIURETAN MINYAK AMPAS KOPI ARABIKA ( Coffea arabica L.)

Polymerization of coffee grounds oil with Diphenyl Methane 4,4 Diisocyanate (MDI), epoxidation with performic acid and H2SO4(p) catalyst at 40-45°C, followed by hydrolysis to obtain polyols. The synthesis was carried out by reacting the polyol with Diphenyl Methane 4,4 Diisocyanate (MDI) with a ratio (polyol: MDI) 9:1; 8:2 ; 7:3 ; 6:4 ; 5:5 (v/v) in dichloromethane solvent. Each was characterized and the density values were 0.9086 gr/cm to 0.4979 gr/cm-1, the tensile strength and elongation values were 0.113 Mpa to 0.299 Mpa and 3.23% to 6.85%, respectively.

Anabolism of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) by Cupriavidus necator DSM 545 from spent coffee grounds oil

Oil extracted from spent coffee grounds (SCG) [yield 16.8 % (w/w)] was discovered to be a highly suitable carbon substrate for the biosynthesis of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) [P(3HB-co-3 HV)] copolymers by Cupriavidus necator DSM 545 in the absence of any traditional 3 HV precursors. Cells cultivated in a 3 L bioreactor (batch) reached a total biomass concentration of 8.9 g L−1 with a P(3HB-co-3 HV) (6.8 mol% 3 HV) content of 89.6 % (w/w). In contrast, cells grown on sunflower oil reached a total biomass concentration of 9.4 gL−1 with a P(3HB-co-3 HV) (0.2 mol% 3 HV) content of 88.1 % (w/w). It is proposed that the organism could synthesize 3 HV monomers from succinyl CoA, an intermediate of the tricarboxylic acid (TCA) cycle, via the succinate-propionate metabolic pathway.

Utilization of Spent Coffee Ground Oil in Eco-Friendly Scouring and Reactive Dyeing Processes for Cotton

In this research, utilizing of Arabica spent coffee ground oil was investigated for textile processing applications including scouring and reactive dyeing for cotton. The spent coffee ground oil was extracted using hexane and its chemical compositions were analyzed. The synthesized biosurfactant from spent coffee ground oil was investigated for use in cotton scouring. The results showed that the biosurfactant could well work as a scouring agent for cotton. Much better water absorption and reduced yellowness on cotton were achieved but higher applied concentration was needed as compared with the commercial wetting agent. It was also found that scouring efficiency of the biosurfactant could be promoted by adding alkali i.e. sodium carbonate, into a scouring bath, resulting in a satisfactory scouring level. A study on utilizing spent coffee ground oil in reactive dyeing process informs that by incorporating the oil into an aqueous dyebath to create oil/water dual-phase dyeing system, the dye exhaustion and color yield of Reactive Red 120 dye obtained on cotton could be enhanced without adding salt. This promotes a development of salt-free reactive dyeing process.

Valorization of spent coffee grounds for biodiesel production: blending with higher alcohols, FT-IR, TGA, DSC, and NMR characterizations

Coffee is a global and popular drink with refreshing properties that is consumed in huge amounts daily. During the brewing process, a valuable dark brown organic waste known as spent coffee grounds (SCG) is generated in bulk. SCG has been classified as a promising raw material for the production of various biofuels and added-value products through biorefineries. This paper aims to valorize SCG into biofuel. Firstly, the oil extracted from SCG (SCGO) has been processed into biodiesel fuel. The oil content of SCG has been found to be ~ 12% (by mass). However, SCGO has an extremely high acid value of ~ 24 mg KOH/g oil. Therefore, biodiesel production was conducted through two steps of acid-catalyzed process followed by alkaline-catalyzed transesterification processes along with methanol and heating at 60 °C. It has been found that the properties of spent coffee grounds oil methyl ester (SCGOME) fulfilled ASTM D 6751 biodiesel standards with cetane number of 54.23, kinematic viscosity of 3.73 mm2/s (at 40 °C), flash point of 137.5 °C, density of 891.9 kg/m3 (at 15 °C), oxidation stability of 5.53 h and higher heating value of 39.37 MJ/kg. This is attributed to its excellent degree of unsaturation of 141.54 and long-chain saturated factor of 6.94. Secondly, the qualities of SCGOME and its binary and ternary blends with Euro diesel and three long-chain alcohols of butanol, pentanol, and octanol were considered in this work. This strategy has resulted in a remarkable improvement in both density and cold flow properties and found very close to Euro diesel. Finally, fast, cheap, and reliable characteristics of DSC, FT-IR, TGA, and NMR were examined for the first time in this work to assess the quality of all blends. Such characteristics proved their quality and reliability. In conclusion, this study supports the ongoing research in valorizing SCG to biodiesel through integrated biorefineries towards sustainable circular bioeconomy. It is recommended to conduct detailed engine, emissions, and combustion tests of the blends in the future studies.

High-pressure fractionation of spent coffee grounds oil using green solvents

Coffee industry generates large amounts of organic waste, including residues obtained during instant coffee production, referred to as spent coffee grounds (SCG). In this work, methods for extraction and fractionation of oil from SCG, focusing on the phenolic compounds content (TPC), were investigated at 333 K and 40 MPa, in one or two steps, with different solvents: pure supercritical CO2 (scCO2), ethanol and supercritical mixture of CO2 with ethanol (90:10 w/w). Fractionation was also evaluated in four separators aligned in series at 323 K at different pressures and ethanol concentrations. The ethanolic extract (E) presented the highest overall yield (25 wt%). Samples from the first separator obtained during fractionation of ethanolic extract showed TPC values up to four times higher than the original extract. Similar TPC enrichment was observed via two-step extraction. The results indicated the methods proposed are efficient to obtain extracts from SCG with higher content of phenolics.