Coffee Grounds Oil Research Articles

Optimization and characterization of n-hexane extracts of arabica coffee ground (Coffea arabica L.) fromgayo plateau as source of natural antioxidant

Arabica coffee is a major commodity crop in the Gayo Plateau, Aceh Province. Utilization of coffee in the area only as a raw material for making coffee drinks and produce waste that is not utilized. The aim of this study is optimization and characterization of n-hexane extract of Arabica Gayo coffee ground (Coffeaarabica L.) as a source of natural antioxidant. The extraction process used soxhlet method with n-hexane solvent. Characterization of arabica coffee ground oil consist ofanalysis of functional group using FTIR, component analysis using GC-MS and antioxidant analysis using DPPH method. The optimum time of the soxhletprocess of Arabica coffee is 180 minutes with rendement of 9,54%, analysis of functional group shows CH2 asymmetric stretch at 2922 cm−1, CH2 symmetric stretch at 2853 cm−1, C=O asymmetric stretch at 1741 cm−1, CH2 bending at 1458 cm−1, C-CH3 vibration at 1159 cm−1 and CH vibration at 718 cm−1. The main component of Arabica Gayo coffee ground oil is 1,2-benzenedicarboxylic acid, bis(2-ethylhexyl) ester with an area of 18.09%, antioxidant activitiy of Arabica Gayo coffee ground oil is very weak with IC50 value = 1222,31 ppm.

Enhanced extraction of spent coffee grounds oil using high-pressure CO2 plus ethanol solvents

This work reports the extraction of spent coffee grounds (SCG) oil using supercritical CO2 plus ethanol (scCO2+EtOH) solvent in semi-batch process as an alternative approach to the use of organic solvent extraction. In addition, the results are compared to supercritical carbon dioxide (scCO2) and pressurized ethanol (EtOH). Soxhlet was performed and used as a standard extraction method. The extraction yield, fatty acid profile, total phenolic content (TPC), antioxidant activity (AA by ABTS and DPPH methods), phenolic compounds and caffeine content were determined, as well the overall extraction curves. The highest extraction yield of 15.9% was obtained using scCO2+EtOH using an ethanol to SCG ratio mass of (2:1), 80 ºC, 20 MPa in 25 min of extraction time. Major fatty acids present in the oil were linoleic (45%) and palmitic (31%). The oil obtained with scCO2+EtOH (2:1) presented high TPC values (294.47 to 392.96 mg GAE/100 g oil), similar to those obtained by pressurized ethanol extraction. High values of AA by ABTS and DPPH methods were also found in the oil from scCO2+EtOH extraction. The main phenolic acids found were dihydroxybenzoic acid and caffeic acid. The highest concentrations of dihydroxybenzoic (17.66 mg/100 g oil) and caffeic acid (9.36 mg/100 g oil) were obtained with scCO2+EtOH (2:1) at 80 ºC and 10 MPa. The highest caffeine content (711.70 mg/100 g oil) was obtained with scCO2+EtOH (0.5:1) at 60 ºC and 15 MPa. The results obtained in this work provided higher extraction yield when compared to scCO2 and similar to compressed ethanol, however in a shorter extraction time and using lesser organic solvent amounts. The results are promising and demonstrate the technical feasibility of SCG oil extraction using scCO2+EtOH to obtain valuable a product from an agricultural and urban waste biomass.

Transesterification of high-acidity spent coffee ground oil and subsequent combustion and emissions characteristics in a compression-ignition engine

Lipids extracted from spent coffee grounds (SCG) are a potentially promising feedstock for biodiesel production if the relatively high free fatty acid (FFA) portion of the oil can be successfully converted into methyl esters, and the resulting biodiesel found to have acceptable combustion and emissions performance. This study presents experimental results obtained from transesterification of SCG-extracted oil with a FFA content of ∼30% w/w through a two-step process, followed by fuel characterization and combustion experiments with SCG-derived biodiesel, pure and blended with fossil diesel, and untreated SCG oil in a single cylinder research compression-ignition engine. The acid-catalyzed pretreatment reduced the FFA content of the oil below 1.5% w/w, with minor losses, and showed the methanol-to-FFA molar ratio to be more significant relative to the quantity of sulphuric acid used as a catalyst within the range of investigated conditions, while the subsequent base-catalyzed step converted ∼87% of the pretreated oil into biodiesel with a higher heating value (HHV) of 39.7 MJ/kg. The combustion and emission characteristics of pure and blended SCG biodiesel revealed similarities with those of commercial rapeseed and soya biodiesel samples tested. While ignition delay decreased with increasing SCG biodiesel content, the comparatively higher CO, total hydrocarbon (THC) and particulate emissions of the SCG biodiesel were attributed to higher fuel kinematic viscosity (KV). Combustion of the untreated SCG oil produced low in-cylinder peak pressure and peak heat release relative to other samples tested despite a longer ignition delay, suggesting that the oil physical properties were more important in determining combustion performance.

Integrated valorization of waste cooking oil and spent coffee grounds for biodiesel production: Blending with higher alcohols, FT–IR, TGA, DSC and NMR characterizations

This work deals for the first time with recycling a binary blend of waste cooking oil (WCO) and spent coffee grounds oil (SCGO) (50/50% by volume) into biodiesel. Additionally, this work aimed at valorizing both wastes while improving fatty acids composition to obtain a stabilized product due to low degree of unsaturation of SCGO besides, reducing its high acid value. Furthermore, blending with Euro diesel and higher alcohols of butanol, pentanol and hexanol to improve some biodiesel properties was investigated. Furthermore, FT–IR, UV–vis., TGA, DSC and NMR analyses to assess the blends quality was examined. Results have proved the advantage of pre-blending and higher alcohols addition to improve the fuel properties. The biodiesel exhibits excellent cetane number of 56.64, oxidation stability of about 6.51 h and iodine value of 83.71 (g iodine/100 g) due to the low degree of unsaturation (89.02). Blending with higher alcohols improves density and cold flow properties while keeping acceptable level of cetane number, flash point and higher heating value (HHV) rather than lower alcohols. Consequently, this opens new gates for biodiesel research area. In conclusion, this work reinforces that blending of WCO and SCGO improves biodiesel properties and add to the economy of this industry. Therefore, further examination on the blends effect in compression ignition diesel engines through engine emissions and combustion characteristics is recommended.

Recovery of spent coffee grounds oil using supercritical CO2: Extraction optimisation and physicochemical properties of oil

ABSTRACTSoxhlet and accelerated solvent extraction, using propanol as a solvent, and supercritical CO2 extraction methods presented statistically insignificant differences in the crude oil yield obtained from spent coffee grounds. Supercritical CO2 extraction method was selected to recover the oil. The optimal extraction condition for a high crude oil yield, low acid value, percentage of free fatty acids, peroxide value and thiobarbituric acid reactive substances (TBARS) value, and high iodine and saponification values, was obtained simultaneously at 50°C, 200 bar and 2 h. Under this condition, the experimental data obtained, namely 12.14% oil yield, acid value 3.89 mg KOH/g oil, 2.11% free fatty acids, iodine value 90.70 g I2/g oil, saponification value 212.05 mg KOH/g oil, peroxide value 3.77 mEqO2/kg oil and TBARS value 0.76 mg malondialdehyde/kg oil, were reasonably close to the predicted values. Additionally, the oil from spent coffee grounds is a precious source of palmitic and linoleic acids.

The flash points and thermal behaviors of diesel blends with biodiesels, α-pinene, d-limonene and caffeic acid as antioxidants

The present study assessed the effects of antioxidants on the flash point and thermal behavior of diesel fuel blended with 3–10 vol% biodiesel made from spent coffee grounds oil (SCGO) or Jatropha seed oil (JSO) extracted using with n-hexane or acetone, with or without α-pinene and d-limonene (as volatile antioxidants) or caffeic acid (as a non-volatile antioxidant). Effects were evaluated by assessing flash points and by thermogravimetry/differential thermogravimetry and differential thermal analysis (DTA). The flash points of the JSO and SCGO biodiesels obtained from oils extracted using n-hexane were higher than those extracted using acetone, and the addition of 10 vol% JSO or SCGO biodiesel made using acetone extraction increased the flash point by up to 2 °C. The DTA results for JSO and SCGO biodiesels also changed according to the extraction solvent. The flash points of diesel/α-pinene/d-limonene mixtures decreased as the amount of α-pinene was increased up to 10 vol%. TG peaks obtained from 10% α-pinene/d-limonene (50 vol%/50 vol%) in diesel were lowered by approximately 20 °C. The addition of 100–1000 mg kg−1 caffeic acid to diesel lowered the flash point by 2 °C and shifted the TG peak to approximately 75 °C from the value of 66 °C for pure diesel. This effect was constant regardless of the caffeic acid content, while DTA results were largely unaffected by this additive. The results of this work confirm that both flash point and thermal behavior are dependent on the particular type of antioxidant employed.

Extraction and esterification of waste coffee grounds oil as non-edible feedstock for biodiesel production

The potential of waste coffee grounds (WCG) as a non-edible feedstock for biodiesel production was evaluated in term of extraction and esterification of waste coffee grounds oil (WCGO). The effect of liquid-solid extraction parameters such as the type and volume of solvent, the extraction time and temperature, and mixing speed were thoroughly investigated. The highest yield of oil extracted from WCGO was 15.47 wt% obtained at a hexane to WCG ratio of 9:1 (v/w) with a mixing speed of 200 rpm and an extraction duration of 5 min at room temperature. An esterification reaction was conducted as a pre-treatment step to reduce the concentration of free fatty acid (FFA), optimized by response surface methodology (RSM) combined with a central composite design (CCD). The results indicated that all the parameters including the methanol (MeOH) to FFA molar ratio, quantity of catalyst, reaction time and temperature were significant for %FFA removal. In the esterification step, the FFA conversion was 95% at the predicted optimization condition which corresponded to the experimental data. Therefore, the results of this study support the utilization of WCGO as a source of non-edible oil feedstock for biodiesel production.

Improvement of oxidation stability of biodiesel by an antioxidant component contained in spent coffee grounds

ABSTRACTIn this work, biodiesel was produced from spent coffee grounds (SCG) oil extracted using n-hexane as a non-polar solvent, and acetone and 1-butanol as polar solvents, in order to simultaneously obtain SCG oil and antioxidant component. Moreover, oxidation stability and antioxidant capacity of SCG oil and their biodiesel production process were evaluated using the Rancimat method and oxygen radical absorbance capacity (ORAC) method, respectively. ORAC values of SCG oil from polar solvents and a non-polar solvent were 97–98 and 93–386 μmol-TE/g, respectively. Antioxidant activities of SCG oils from polar solvents were higher than those of SCG oil from non-polar solvent. However, these ORAC values were decreased by one third on raw oils during biodiesel production model experimental. These characteristics were utilized to develop an improved method of producing waste rapeseed biodiesel: (1) blending the SCG oil with rapeseed oil; (2) soaking powdered SCG in the reaction mixture during biodiesel production; and (3) adding active components extracted using methanol. In method (1), oxidation stability was improved such that 10 wt% of polar solvent extracted SCG oils increased the stability from 1 to 3 h. Also, oxidation stabilities in methods (2) and (3) were improved by soaking 40 wt% SCG and adding 1 wt% SCG extract, respectively.

Physicochemical Characterization of Robusta Spent Coffee Ground Oil for Biodiesel Manufacturing

Oil extracted from spent coffee ground (SCG) has been well known as a potential feedstock for high quality biodiesel production. This work was to investigate extraction, physical and chemical characterizations of Robusta coffee oil (CO) and its application for biodiesel production. Analysis of seven coffee ground (CG) samples showed that oil content in CGs depended on technique of the manufacturer. Morphological changes of CGs surface were recorded by FESEM technique which showed the particle size significantly increased with the oil loss. Infrared spectroscopies revealed absence of SCG oil in the de-oiled SCG, confirmed that soxhlet method in hexane was used efficiently for the oil extraction. Thermal properties of SCG oil, fresh coffee ground (FCG), SCG and de-oiled SCG samples were investigated by simultaneous TG–DTA measurement. The obtained data showed the oil content relating to thermal changes of SCG samples. Comparison between chemical components of Robusta coffee bean (RCB) and SCG reflected a fact that most of oil content in the SCG could be originated in manufacturing process of FCG. Quality biodiesel product has prepared from SCG oils via a two-step process. After pre-treatment process, transesterification of SCG oils was carried out with methanol (v/v, 30%) and NaOH (w/v, 1%) in yield 89.2%.

Study of Coffee Grounds Oil Action in PVC Matrix Exposed to Gamma Radiation: Comparison of Systems in Film and Specimen Forms

The poly (vinyl chloride), PVC, undergoes changes in its physicochemical properties when it is exposed to gamma radiation. Thus, the radiolytic stabilization of PVC is one way for obtain a material with radiation resistance. In this work, we studied the coffee grounds oil as PVC radiolytic protection in two systems forms: PVC film and PVC specimen. The systems were irradiated at sterilization dose of medical devices and viscosity measurements were performed. According to viscosity assays of PVC films, there was a 67% protection in polymer matrix promoted by the oil. On the other hand, the mean viscosity molar mass (Mv) of PVC specimens increased about 13%, indicating predominance of crosslinking effect, however samples containing the oil showed no Mv significant changes. Therefore, the oil can be considered a PVC radio stabilizing substance and open a way for use of sustainable additive in PVC industry.

Topical use and systemic action of green and roasted coffee oils and ground oils in a cutaneous incision model in rats (Rattus norvegicus albinus).

IntroductionWounds are a common health problem. Coffee is widely consumed and its oil contains essential fatty acids. We evaluated the local (skin) and systemic effects associated with the topical use of coffee oils in rats.MethodsPunch skin wounds (6 mm) incisions were generated on the backs of 75 rats. Saline (SS), mineral oil (MO), green coffee oil (GCO), roasted coffee oil (RCO), green coffee ground oil (GCGO) or roasted coffee ground oil (RCGO) were topically applied to the wounds. Healing was evaluated by visual and histological/morphometric optical microscopy examination; second harmonics generation (SHG) microscopy, wound tissue q-PCR (values in fold-change) and blood serum (ELISA, values in pg/mL).ResultsRCO treated animals presented faster wound healing (0.986 vs. 0.422), higher mRNA expression of IGF-1 (2.78 vs. 1.00, p = 0.01), IL-6 (10.72 vs. 1.00, p = 0.001) and IL-23 (4.10 vs. 1.2, p = 0.05) in early stages of wound healing; higher IL-12 (3.32 vs. 1.00, p = 0.05) in the later stages; and lower serum levels of IFN-γ (11.97 vs. 196.45, p = 0.01). GCO treatment led to higher mRNA expression of IL-6 (day 2: 7.94 vs. 1.00, p = 0.001 and day 4: 6.90 vs. 1.00, p = 0.01) and IL-23 (7.93 vs. 1.20, p = 0.001) in the early stages. The RCO treatment also produced higher serum IFN-α levels throughout the experiment (day 2: 52.53 vs. 21.20; day 4: 46.98 vs.21.56; day 10: 83.61 vs. 25.69, p = 0.05) and lower levels of IL-4 (day 4: 0.9 vs.13.36, p = 0.01), adiponectin (day 10: 8,367.47 vs. 16,526.38, p = 0.001) and IFN-γ (day 4: 43.03 vs.196.45, p = 0.05). The SHG analysis showed a higher collagen density in the RCO and GCO treatments (p = 0.05).ConclusionTopical treatment with coffee oils led to systemic actions and faster wound healing in rats. Further studies should be performed are necessary to assess the safety of topical vegetal oil use for skin lesions.

Statistical Optimization for Esterification of Waste Coffee Grounds Oil using Response Surface Methodology

Biodiesel is alternative bio-fuel to substitute for diesel fuel which produces harmful emission causing environmental problems. The common feedstock for biodiesel production was edible oil which effected to high production cost. In order to conquer this problem, waste material was appeared to be an attractive choice. The oil from waste coffee grounds (WCGs) has the potential to use as raw material. However, high free fatty acid (FFA) concentration (>1%) in extracted oil from WCGs requires pretreatment prior to transesterification. Therefore, FFA was treated by using sulfuric as acid catalytic. In this study, the optimization of esterification of extracted oil from WCGs was investigated by using response surface methodology (RSM). The effect of operation parameters to pre-treatment of FFA was conducted using laboratory scale. The predicted optimum condition results indicated that %FFA of the waste coffee grounds oil (WCGO) was decreased 94.97% when the condition was carry out with methanol 10 mole per mole of FFA in the presence of 15% w/w of %FFA-to-catalyst ratios for 115 min reaction time at 65°C.

Assessment of the Physico-Chemical Properties of Waste Cooking Oil and Spent Coffee Grounds Oil for Potential Use as Asphalt Binder Rejuvenators

Recycling of waste is an optional approach across industries to reduce environmental harm and turn it into sustainable and valuable resource alternatives. This paper addresses recycling of food industry waste through exploring potential use to enhance damaged asphalt binder used in roadways. The two wastes, spent coffee grounds and waste cooking oil were subjected to different levels of oxidation after which their physical and chemical properties were analyzed. Results show that oxidation significantly affects the oils by increasing the release of fatty acids and breaking of double bonds. The latter, in addition to polymerization and release of high molecular weight compounds, increases the viscosities of the oils while retaining their Newtonian behavior. As such, oxidation may be able to effectively customize physicochemical properties of oils, namely viscosity, for their reported application as asphalt binder rejuvenators. The rejuvenated binder can then be reused in production of asphalt for low traffic roadways.

Biodiesel Production from Spent Coffee Grounds

Abstract The residue after brewing the spent coffee grounds is an oil-containing waste material having a potential of being used as biodiesel feedstock. Biodiesel production from the waste coffee grounds oil involves collection and transportation of coffee residue, drying, oil extraction, and finally production of biodiesel. Different methods of oil extraction with organic solvents under different conditions show significant differences in the extraction yields. In the manufacturing of biodiesel from coffee oil, the level of reaction completion strongly depends on the quality of the feedstock oil. This paper presents an overview of oil extraction and a method of biodiesel production from spent coffee grounds.

The green generation of sunscreens: Using coffee industrial sub-products

Spent coffee grounds and green coffee defective beans, which are industrial sub-products of coffee processing, have a potential use for cosmetic applications, due to their safety and high content in lipids that present interesting physicochemical properties. Sunscreen formulations in the form of water-in-oil emulsions might be a suitable application for these sub-products because providing a higher sun protection factor (SPF) for the same concentration of sunscreen activities than oil-in-water emulsions.The purpose of this work was to assess the biological effects of using the oil fraction of spent coffee grounds extracted with supercritical CO2 and green coffee oil in the development of new generation of sunscreens with improved sun protection performance. The oil fractions were used to prepare w/o sunscreens involving a cold emulsification process, with purified water as disperse aqueous phase and TiO2 and ZnO particles as stabilizers. The sunscreens were characterized in terms of mechanical, rheological and skin adhesion properties. In addition, the in vitro and in vivo biological properties of the formulations were evaluated, including safety and sunscreen water resistance tests.The use of two types of solid particles proved to be useful in the developed formulations, ensuring a high SPF with UVB/A protection, conferred by TiO2 and ZnO, respectively. Moreover, the emulsion containing 35% w/w of the spent coffee grounds oil fraction presented promising characteristics in the improvement of water performance with a broad spectrum sun protection when compared to an emulsion containing 35% w/w of green coffee oil which improved the SPF in physical sunscreens. The formulations are industrial-scalable and suitable for topical use according to the rheological, mechanical and safety assessment.The use of spent coffee oil in cosmetic industry seems to be a suitable approach for the valorisation of waste from the coffee industry and presents promising characteristics in the improvement of sunscreen performance.

Integrated volarization of spent coffee grounds to biofuels

Biodiesel is a renewable energy source produced from natural oils and fats, and is being used as a substitute for petroleum diesel. The aim of this study was to investigate the potential of using spent coffee grounds for biodiesel production and its by-products to produce pelletized fuel, which is expected to help the biodiesel production process achieve zero waste. For this experiment, spent coffee grounds sample was collected from Kaldis coffee, Addis Ababa, Ethiopia. Extraction of the spent coffee grounds oil was then conducted using n-hexane, ether and mixture of isopropanol to hexane ratio (50:50 %vol), and resulted in oil yield of 15.6, 17.5 and 21.5 %w/w respectively. A two-step process was used in biodiesel production with conversion of about 82 %w/w. The biodiesel quality parameters were evaluated using the American Standard for Testing Material (ASTM D 6751). The major fatty acid compositions found by Gas chromatography were linoleic acid (37.6%), palmitic acid (39.8%), oleic (11.7%), and stearic acid (8.6%). In addition, solid waste remaining after oil extraction and glycerin ratio (glycerin content from 20-40%) was evaluated for fuel pellet (19.3-21.6 MJ/Kg) applications. Therefore, the results of this work could offer a new perspective to the production of biofuel from waste materials without growing plants and/or converting food to fuel.

Production of polyhydroxyalkanoates from spent coffee grounds oil obtained by supercritical fluid extraction technology

Spent coffee grounds (SCG) oil was obtained by supercritical carbon dioxide (scCO2) extraction in a pilot plant apparatus, with an oil extraction yield of 90% at a 35kgkg(-1) CO2/SCG ratio. Cupriavidus necator DSM 428 was cultivated in 2L bioreactor using extracted SCG oil as sole carbon source for production of polyhydroxyalkanoates. The culture reached a cell dry weight of 16.7gL(-1) with a polymer content of 78.4% (w/w). The volumetric polymer productivity and oil yield were 4.7gL(-1)day(-1) and 0.77gg(-1), respectively. The polymer produced was a homopolymer of 3-hydroxybutyrate with an average molecular weight of 2.34×10(5) and a polydispersity index of 1.2. The polymer exhibited brittle behaviour, with very low elongation at break (1.3%), tensile strength at break of 16MPa and Young's Modulus of 1.0GPa. Results show that SCG can be a bioresource for polyhydroxyalkanoates production with interesting properties.

Investigation of Waste Coffee Ground as a Potential Raw Material for Biodiesel Production

In this study, the utilization of waste coffee ground for biodiesel production was investigated. Waste coffee ground sample was collected from TOMOCA PLC, Addis Ababa, Ethiopia. The oven dried sample was then soxhlet extracted using n- hexane to yield 19.73 %w/w oil. The biodiesel was obtained by a two-step process, i.e. acid catalyzed esterification followed by base catalyzed transesterification using catalysts sulphuric acid and sodium hydroxide respectively. The conversion of waste coffee ground oil in to biodiesel, was about 73.4%w/w. Various parameters that are essential for biodiesel quality were evaluated using the American Standard for Testing Material (ASTM D 6751- 09) and all comply with the specification except acid value. The fatty acid composition of the biodiesel was analyzed by Gas chromatography and the major fatty acids were found to be linoleic acid (39.8%), palmitic acid (37.6%), oleic (12.7%), and stearic acid (7.6%). In addition, preliminary investigation on the solid waste remaining after oil extraction was conducted for possible use as a feedstock for the production of bioethanol. Hydrolysis of the spent of waste coffee ground was carried out using dilute sulphuric acid followed by fermentation using Saccharomyces cereviciae, and resulted in bioethanol yield of 8.3 %v/v. Furthermore, the solid waste remaining after bioethanol production was evaluated for compost (21.9:1 C/N) and solid fuel (20.8 MJ/Kg) applications. The results of this research work give insights on the production of biofuel from waste ground coffee. In addition, the preliminary analysis on the solid waste after the extraction of the oil suggests that it can be used as fuel hence alleviating major disposal problems.

Synthesis of fatty acid methyl esters via direct transesterification with methanol/carbon dioxide mixtures from spent coffee grounds feedstock

The feasibility of in situextraction and transesterification of spent coffee ground oil into fatty acid methyl esters with supercritical methanol has been investigated in the temperature range 473–603 K, and in the pressure range 10.0–30.0 MPa. At 30.0 MPa and 603 K, a fatty acid methyl esters (FAME) yield of 84.9% was obtained. Carbon dioxide was added to methanol with the aim of reducing the operating temperature and pressure. It was demonstrated that at a reaction temperature of 573 K, pressure of 10.0 MPa and a CO2/MeOH molar ratio of 0.11, a FAME yield of 93.4% was obtained.