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This work presents a way to use ethanol and spent coffee grounds (SCG) as feedstocks for biodiesel production to solve ethanol overproduction in Thailand and biodiesel feedstock shortage problems together. Waste coffee oil (SCGO) was ethanolic extracted from SCG; then, ethanol-SCGO mixture was transesterified in supercritical condition without ethanol removal. The ethanolic extraction curves of SCG at a temperature range of 50–70 °C were constructed. Transesterification experiments were studied in a batch reactor and a continuous reactor at various temperatures (275–350 °C) and reaction time (5–40 min) under 15.0 MPa. The molar ratio of ethanol-oil mixture was set at 30:1. The highest ester content of 88.37 ± 3.00 wt% was found in biodiesel obtained at a temperature of 275 °C and a reaction time of 40 min in a batch reactor. Furthermore, excess temperature (< 300 °C) and reaction time (< 20 min) induced thermal degradation and promoted the loss of ethyl linoleate. For continuous reactor, the maximum ester content of 83.38 ± 5.86 wt% was observed at 325 °C and 29.4 min of residence time. Unlike in batch reactors, thermal degradation of ethyl linoleate was not observed in a continuous reactor. The results showed that ethanolic extraction and supercritical transesterification are alternative ways to produce biodiesel from SCG without removing extractant and using catalyst. From a prospective point of view, techno-economic analysis (TEA) and life-cycle assessment (LCA) of invented process should be conducted to ensure profitability and environmental benefits, respectively. [ABSTRACT FROM AUTHOR]

Spent coffee grounds (SCGs) are a significant waste product generated from coffee consumption, presenting environmental challenges while containing up to 20% coffee oil rich in beneficial compounds suitable for various industries. This research focuses on extracting and characterizing coffee oil from SCGs to explore its bioactive substances. The material for this research was coffee waste gathered from a coffee machine, containing 95% Robusta and 5% Arabica. This coffee waste was subsequently subjected to thermal drying in an oven at 102 0C for 3 hours to remove any water content. Following the drying process, the samples were carefully stored at room temperature. Utilizing Soxhlet extraction with n-hexane, a coffee oil yield of 9.43% was achieved. The pH value of the extracted oil was assessed using the Benchtop Biobase 210 pH meter - China. Extracted oil underwent ATR-FTIR analysis, revealing characteristic bands corresponding to various oil compounds. pH of the coffee oil samples was determined to be 6.5 at 25 0C. Notably, the peak at 3009 cm-1 indicates the presence of unsaturated fatty acids, while bands at 2850 cm-1 and 2921 cm-1 confirm the presence of hydrocarbons. Additionally, bands at 1748 cm-1 and 1150 cm-1 confirm the presence of triglycerides. This study highlights the abundant bioactive substances found in coffee oil, representing a significant advancement in sustainable waste management strategies. [ABSTRACT FROM AUTHOR]

The valorization of renewable feedstock to produce a plethora of value-added products could promote the transition towards a circular bioeconomy. This study presents the development of cascade processes to bioconvert spent coffee grounds (SCGs) into microbial oil and carotenoids employing sustainable practices. The stepwise recovery of crude phenolic extract and coffee oil was carried out using green or recyclable solvents, i.e., aqueous ethanol and hexane. Palmitic acid (43.3%) and linoleic acid (38.9%) were the major fatty acids in the oil fraction of SCGs. The LC–MS analysis of crude phenolic extracts revealed that chlorogenic acid dominated (45.7%), while neochlorogenic acid was also detected in substantial amounts (24.0%). SCGs free of coffee oil and phenolic compounds were subjected to microwave-assisted pretreatment under different irradiations and solvents to enhance subsequent enzymatic saccharification. Microwave/water pretreatment at 400 W, followed by enzymatic hydrolysis with proteases, hemicellulases, and cellulases, at 50 g/L initial SCGs, led to satisfying overall yields of cellulose (75.4%), hemicellulose (50.3%), and holocellulose (55.3%). Mannan was the most extractable polysaccharide followed by galactan and arabinan. SCGs hydrolysate was used in fed-batch bioreactor fermentations with Rhodosporidium toruloides to produce 24.0 g/L microbial oil and carotenoids of 432.9 μg/g biomass. [ABSTRACT FROM AUTHOR]

Green coffee processing has been hindered by low oil extraction yields from mechanical pressing and the need of using flammable and hazardous solvents for defatting the protein-rich cake before subsequent protein extraction. To replace the use of flammable solvents and enable the simultaneous extraction of lipids and proteins from green coffee beans at reduced water usage, a multistage countercurrent extraction process was scaled up from 0.05 to 1.14 kg and evaluated regarding protein and oil extractability, physicochemical and functional properties of the extracted protein, and oil recovery. Enzymatic extraction increased protein extractability by ~13% while achieving similar oil extractability when not using enzymes (55%). Proteolysis resulted in the release of smaller proteins with reduced surface hydrophobicity and higher solubility at acidic pH (3.0–5.0). The physicochemical changes observed due to proteolysis resulted in the formation of emulsions with reduced resistance against enzymatic and chemical demulsification strategies, enhancing the recovery of the extracted oil (48.6–51.0%). Proteolysis did not alter the high in vitro digestibility of green coffee proteins (up to 99%) or their emulsifying properties at most pH values evaluated. However, proteolysis did reduce the foaming properties of the hydrolysates compared with larger molecular weight proteins. These findings revealed the impact of extraction conditions on the extractability and structural modifications altering the functionality of green coffee proteins and the synergistic impact of extraction and demulsification strategies on the recovery of the extracted oil, paving the way for the development of structure–function processes to effectively produce green coffee proteins with desired functionality.

Copyright of Journal of Dalian University of Technology / Dalian Ligong Daxue Xuebao is the property of Journal of Dalian University of Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Arabic coffee is a daily traditional drink in Kuwait and Arabian Peninsula countries. Scientific studies indicated the presence of oil in this coffee waste. The oil extracted from coffee has many health and industrial uses. This study evaluates Arabic coffee consumption in Kuwait through a survey and then studies oil extraction efficiency from the waste coffee ground. Results of the cross-sectional survey showed that most study participants consume Arabic coffee at least four times a week, and about half of the respondents were prompt to keep the waste for further treatment. Experimental extraction showed that the amount of oil isolated from plain coffee waste was higher when no additives were added. Cardamom and other coffee additives work as emulsifiers to enhance oil leaching in coffee preparation; in other words, less oil is left in the spent coffee grounds. [ABSTRACT FROM AUTHOR]

The production of green coffee oil by mechanical pressing of green coffee beans has been precluded by low extraction yields, which generates a protein-rich byproduct (cake) containing variable amounts of lipids. Subsequent utilization of the cake requires the removal of the residual cake oil by solvent extraction. An eco-friendly extraction strategy, using water, enzymes, and mechanical treatments, was evaluated to concurrently extract lipids and proteins from green coffee flour, without the use of harsh solvents. Among the enzymatic treatments evaluated, the use of 0.5% alkaline protease led to higher protein (62.2%) and oil (47.7%) extractability in a shorter time (30 min). This enzymatic treatment was optimized with respect to solids-to-liquid ratio (SLR) (1:17.5-1:7) and concentration of enzyme (0.1-0.9% w/w). Although optimum extraction conditions (1:17.5 SLR and 0.1% enzyme) achieved high protein (70%) and oil (48%) extractability and reduced enzyme use by 80%, a higher water usage was required. Therefore, a two-stage countercurrent extraction was developed to reduce water usage in the process. The countercurrent extraction strategy not only reduced the amount of water used in the process by 60% but promoted higher protein (72%) and oil (58%) extractability, compared with the single-stage process (62.2 and 47.7%, respectively).

Defective green coffee beans are typically discarded due to their negative impacts on coffee qualities compared to normal beans. However, there are some types of defective beans that can cause volatile aroma compounds after roasting similar to those produced by normal beans. This study aimed to optimize conditions for coffee oil extraction by supercritical carbon dioxide using the response surface methodology (RSM). Furthermore, the investigation assessed the aroma-active compounds and sensory quality in extracted coffee oil. Thus, operational temperatures (33.2–66.8 °C), pressure (10–30 MPa) and ethanol (g) to roasted coffee (g) ratio (0.25:1–1.5:1) were optimized for coffee oil extraction. As a result, different oil yields with different key volatile aroma compounds concentrations were obtained and it was found that the optimum conditions for extraction were a temperature of 50 °C, pressure of 30 MPa, and ethanol (g) to roasted coffee (g) ratio of 1:1 to obtain 6.50% (w/w) coffee oil yield. Key volatile aroma compounds, including furfuryl alcohol, 5-methyl furfural, 2,5-dimethylpyrazine, 4-vinylguaiacol, furfuryl acetate, 3-ethyl-2,5-dimethylpyrazine, thiazole, 1-furfurylpyrrole, pyridine, 2,3-butanediol, and 3-methyl-1,2-cyclopentanedione which contributed to the most preferable burnt, sweet, bready, chocolate-like, and roasted flavors, were quantified. Overall, the results suggested that coffee oil extracted from defective beans could be potentially used as a flavoring agent. [ABSTRACT FROM AUTHOR]

Microalgae are mostly phototrophic microorganisms present worldwide, showcasing great adaptability to their environment. They are known for producing essential metabolites such as carotenoids, chlorophylls, sterols, lipids, and many more. This study discusses the possibility of the mixotrophic abilities of microalgae in the presence of food waste oils. The utilization of food waste materials is becoming more popular as a research subject as its production grows every year, increasing the environmental burden. In this work, waste frying oil and coffee oil were tested for the first time as a nutrition source for microalgae cultivation. Waste frying oil is produced in large amounts all over the world and its simple purification is one of its greatest advantages as it only needs to be filtered from leftover food pieces. Coffee oil is extracted from waste spent coffee grounds as a by-product. The waste frying oil and coffee oil were added to the basic algal media as an alternative source of carbon. As a pilot study for further experimentation, the effect of oil in the medium, algal adaptability, and capability to survive were tested within these experiments. The growth and production characteristics of four algae and cyanobacteria strains were tested, of which the strain Desmodesmus armatus achieved exceptional results of chlorophyll (8.171 ± 0.475 mg/g) and ubiquinone (5.708 ± 0.138 mg/g) production. The strain Chlamydomonas reindhartii showed exceptional lipid accumulation in the range of 30–46% in most of the samples. [ABSTRACT FROM AUTHOR]

Featured Application: The investigated additives for water-based lubricating fluids could be used in applications where aqueous lubricants are employed. These could be hydraulic or metalworking applications. Lubrication is the primary solution to reduce friction and wear. However, conventional lubricants cause pollution when not properly disposed of or due to accidental leaks. Therefore, environmentally friendly lubricating fluids are welcome in any application where they can meet the performance requirements. This study suggests using coffee oil produced from spent coffee grounds to improve the lubricity of water-based lubricating fluid. Bis(2-hydroxyethyl)ammonium oleate protic ionic liquid facilitates the dispersion of coffee oil in water. Kinematic viscosity, wettability, corrosion prevention, and lubricity tests were performed to evaluate the tribological properties provided by these additives. It was observed that a higher amount of coffee oil could be dispersed with the introduction of a higher amount of protic ionic liquid. In this study, ten wt.% of coffee oil was successfully dispersed using one wt.% of protic ionic liquid. Introducing additives increased dispersions' viscosity, improved wettability, provided protection against corrosion, and reduced wear and friction. It was proposed that polar molecules of protic ionic liquid were responsible for most of the improvement, while coffee oil contributed by increasing viscosity. Further studies could be directed toward determining rational concentration to meet each particular application's requirements. [ABSTRACT FROM AUTHOR]

With the increasing consumption of coffee beverages, an increased amount of food waste—spent coffee grounds (SCG)—is generated and disposed into landfills or combusted in incinerators. SCG are characterized as a highly polluting substance with partial toxicity due to the presence of caffeine, tannins, and polyphenols. It also contains 15% of oil on average, and its potential for biodiesel production is thus considerable. The aim of the presented work is to evaluate the possibility and technical potential of biodiesel production from the SCG oil (SCGO) by esterification and transesterification reaction. According to the characterization of the studied SCGO, this stream must be adjusted and purified to be utilized in the existing biodiesel production plant. Fatty acids (FA) represent 85.85% of the SCGO, with two dominant FAs—linoleic and palmitic acids. The necessity of removal and disposal of unsaponifiable matter, which accounts for 15% of the SCGO content, must be highlighted when producing biodiesel from the SCG. The objective of this research was the comparison of different biodiesel production processes, where a two-step transesterification process has been identified as the most successful method for biodiesel production from the SCGO with the highest ester content of 89.62% and the lowest content of unsaponifiable and unidentified matter in the final product. The novelty of the analyses is a characterization of the d unsaponifiable matter present in the SCGO, and the article highlights the importance of progression to be considered when evaluating the technical potential of the SCG biodiesel production integrated into a biorefinery. Nevertheless, the SCG biodiesel can contribute to fulfilling the mandatory share of advanced biofuel in the fuel energy mix given by national legislation and contribution to the circular economy approach of biorefineries. [ABSTRACT FROM AUTHOR]

[Display omitted] • Spent coffee grounds as a sustainable resource for phase change material. • Extracted coffee oil with a melting point of 4.5 °C and latent heat of 51.1 J/g. • Potential use of coffee oil for low-temperature thermal energy storage applications. Spent coffee grounds (SCGs) are waste residues arising from the process of coffee brewing and are usually sent to landfills, causing environmental concerns. SCGs contain a considerable amount of fatty acids and is therefore a promising green alternative bio-based phase change material (PCMs) compared to conventional organic and inorganic PCMs. In this study, the extraction of coffee oil from SCGs was conducted using three different organic solvents-ethanol, acetone, and hexane. The chemical composition, chemical, and thermophysical properties of these coffee oil extracts were studied to evaluate their feasibility as a bio-based PCM. Gas chromatography-mass spectroscopy (GC–MS) analysis indicated that coffee oil contains about 60–80 % of fatty acids while the phase transition temperature of the coffee oil extracts is approximately 4.5 ± 0.72 °C, with latent heat values of 51.15 ± 1.46 J/g as determined by differential scanning calorimetry (DSC). Fourier Transform Infrared Spectroscopy (FTIR) and DSC results of coffee oil extracts after thermal cycling revealed good thermal and chemical stability. An application study to evaluate coffee oil extract as a potential cold therapy modality showed that it can maintain temperatures below normal body temperature for up to 46 min. In conclusion, this work exemplifies the potential of SCGs as a promising green and sustainable resource for bio-based PCMs for low-temperature thermal energy storage applications such as cold-chain transportation and cold therapy. [ABSTRACT FROM AUTHOR]

This study was designed to determine the levels of coffee oil and diterpenes and evaluate the correlation between the effect of excessive roasted coffee consumption on non-high-density lipoprotein cholesterol (non-HDL) and the roasting degree effect on the levels of coffee oil and diterpenes extracted from Coffea arabica. The coffee oil and diterpenes were extracted using soxhlet and liquid-liquid extraction. Sixty-six healthy normolipidemic male participants were assigned for this study which consisted of two stages. The first stage is the coffee abstaining stage where subjects were requested to abstain from drinking coffee for 2 weeks. The second stage is the coffee drinking stage which consisted of groups (the control group and coffee-drinking group). The levels of TC, TG, LDL-C, HDL-C, and non-HDL were determined in all participants before and after the experiment. The results indicated that the coffee roasting degree demonstrated a significant increase in the levels of coffee oil and diterpenes ranging from 9.31% (green coffee) to 15.64% (dark roast) and from 0.205% (green coffee) to 0.300% (dark roast) for diterpenes. In conclusion, the current study revealed that excessive consumption of medium roasted coffee was associated with elevated non-HDL levels in normotensive nonsmoker healthy men which might be attributed to the positive association between the degree of roasting and diterpenes levels. [ABSTRACT FROM AUTHOR]

The valuable products that can be isolated from spent coffee ground (SCG) biomass consist of a high number of bioactive components, which are suitable for further application as raw materials in various production chains. This paper presents the potential value of the SCG obtained from large and local coffee beverage producers, for the production of valuable, biologically active products. Despite its high potential, SCG has not been utilized to its full potential value, but is instead discarded as waste in landfills. During its decomposition, SCG emits a large amount of CO2 and methane each year. The main novelty of our work is the implementation of sequential extraction with solvents of increased polarity that allows for the maximal removal of the available extractives. In addition, we have compared different extraction techniques, such as conventional and Soxhlet extraction, with more effective accelerated solvent extraction (ASE), which has seen relatively little use in terms of SCG extraction. By comparing these extraction methods and highlighting the key differences between them in terms of extraction yield and obtained extract composition, this work offers key insights for further SCG utilization. By using sequential and one-step accelerated solvent extraction, it is possible to obtain a significant number of extractives from SCG, with a yield above 20% of the starting biomass. The highest yield is for coffee oil, which is obtained with n-hexane ranging between 12% and 14% using accelerated solvent extraction (ASE) according to the scheme: n-hexane→ethyl acetate→60% ethanol. Using single-stage extraction, increasing the ethanol concentration also increases the total phenolic content (TPC) and it ranges between 18.7–23.9 Gallic acid equivalent (GAE) mg/g. The iodine values in the range of 164–174 using ASE and Soxhlet extraction shows that the hexane extracts contain a significant amount of unsaturated fatty acids; coffee oils with a low acid number, in the range of 4.74–6.93, contain few free fatty acids. The characterization of separated coffee oil has shown that it mainly consists of linoleic acid, oleic acid, palmitic acid, stearic acid and a small number of phenolic-type compounds. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

This study focused on identifying the best conditions and studying the effects of the operational variables on the integral valorization process of used coffee ground. The valorization approach was defined in two successive steps: oil extraction and using the remaining residue to prepare activated carbon. For this purpose, a set of experiments was designed to test the following four variables in the oil extraction stage: (A) drying time (50 °C/12 h and 105 °C/6 h), (B) relative polarity of hexane and ethanol (0.009 and 0.654 a.u.), (C) solvent ratio (10 and 12 mL/g), and (D) extraction time (30 and 60 min). The best conditions from the corresponding experiments (50 °C/12 h, using ethanol as a solvent in a 12:1 solvent ratio (v/v) with 30 min of extraction time) resulted in the extraction of 0.4 g of oil per gram of spent coffee ground. This value is, to the best of our knowledge, the highest reported thus far and is a result combining of the coffee origin and the significant interactions found for the tested parameters. For the stage of activated carbon preparation, the (E) activating agent ratio (1, 2, and 3 gAA/gS) and the (F) carbonization temperature (450, 550, and 700 °C) were considered independent variables. The corresponding results indicate that 1 gAA/gS and 450 °C are the best conditions, resulting in a sorption capacity of 29 mg/g, which is similar to the value obtained for commercial activated carbon. Physicochemical analysis on the other hand, showed that extracted coffee oil is characterized by a high content of free fatty acids; thus, an additional purification process could be considered to obtain a precursor for biodiesel. Activated carbon was found to have an elemental composition similar to that of vegetal activated carbon. The adsorption kinetics of the activated carbon obtained from the spent coffee residues are characterized by a pseudo-second-order model that suggests chemisorption-controlled phenomena. [ABSTRACT FROM AUTHOR]

Microalgae are mostly phototrophic microorganisms present worldwide, showcasing great adaptability to their environment. They are known for producing essential metabolites such as carotenoids, chlorophylls, sterols, lipids, and many more. This study discusses the possibility of the mixotrophic abilities of microalgae in the presence of food waste oils. The utilization of food waste materials is becoming more popular as a research subject as its production grows every year, increasing the environmental burden. In this work, waste frying oil and coffee oil were tested for the first time as a nutrition source for microalgae cultivation. Waste frying oil is produced in large amounts all over the world and its simple purification is one of its greatest advantages as it only needs to be filtered from leftover food pieces. Coffee oil is extracted from waste spent coffee grounds as a by-product. The waste frying oil and coffee oil were added to the basic algal media as an alternative source of carbon. As a pilot study for further experimentation, the effect of oil in the medium, algal adaptability, and capability to survive were tested within these experiments. The growth and production characteristics of four algae and cyanobacteria strains were tested, of which the strain Desmodesmus armatus achieved exceptional results of chlorophyll (8.171 ± 0.475 mg/g) and ubiquinone (5.708 ± 0.138 mg/g) production. The strain Chlamydomonas reindhartii showed exceptional lipid accumulation in the range of 30–46% in most of the samples.

Defective green coffee beans are typically discarded due to their negative impacts on coffee qualities compared to normal beans. However, there are some types of defective beans that can cause volatile aroma compounds after roasting similar to those produced by normal beans. This study aimed to optimize conditions for coffee oil extraction by supercritical carbon dioxide using the response surface methodology (RSM). Furthermore, the investigation assessed the aroma-active compounds and sensory quality in extracted coffee oil. Thus, operational temperatures (33.2–66.8 °C), pressure (10–30 MPa) and ethanol (g) to roasted coffee (g) ratio (0.25:1–1.5:1) were optimized for coffee oil extraction. As a result, different oil yields with different key volatile aroma compounds concentrations were obtained and it was found that the optimum conditions for extraction were a temperature of 50 °C, pressure of 30 MPa, and ethanol (g) to roasted coffee (g) ratio of 1:1 to obtain 6.50% (w/w) coffee oil yield. Key volatile aroma compounds, including furfuryl alcohol, 5-methyl furfural, 2,5-dimethylpyrazine, 4-vinylguaiacol, furfuryl acetate, 3-ethyl-2,5-dimethylpyrazine, thiazole, 1-furfurylpyrrole, pyridine, 2,3-butanediol, and 3-methyl-1,2-cyclopentanedione which contributed to the most preferable burnt, sweet, bready, chocolate-like, and roasted flavors, were quantified. Overall, the results suggested that coffee oil extracted from defective beans could be potentially used as a flavoring agent.

Lubrication is the primary solution to reduce friction and wear. However, conventional lubricants cause pollution when not properly disposed of or due to accidental leaks. Therefore, environmentally friendly lubricating fluids are welcome in any application where they can meet the performance requirements. This study suggests using coffee oil produced from spent coffee grounds to improve the lubricity of water-based lubricating fluid. Bis(2-hydroxyethyl)ammonium oleate protic ionic liquid facilitates the dispersion of coffee oil in water. Kinematic viscosity, wettability, corrosion prevention, and lubricity tests were performed to evaluate the tribological properties provided by these additives. It was observed that a higher amount of coffee oil could be dispersed with the introduction of a higher amount of protic ionic liquid. In this study, ten wt.% of coffee oil was successfully dispersed using one wt.% of protic ionic liquid. Introducing additives increased dispersions’ viscosity, improved wettability, provided protection against corrosion, and reduced wear and friction. It was proposed that polar molecules of protic ionic liquid were responsible for most of the improvement, while coffee oil contributed by increasing viscosity. Further studies could be directed toward determining rational concentration to meet each particular application’s requirements.

While the cholesterol-raising effect of coffee has been ascribed to the presence of diterpenes, they have also been shown to present favourable health effects. Boiled-type coffees show slightly higher levels of diterpenes than those made with other brewing methods. However, there is considerable controversy regarding the effect of roasting on the contents of the diterpenes cafestol and kahweol. Therefore, the aim of the present work was to measure the contents of these diterpenes in Turkish coffees, and to determine how they are influenced by roasting. The samples used were 16 roasted and ready-ground Turkish coffees sold in supermarkets in the Turkish Republic of Northern Cyprus. The cafestol and kahweol contents of the coffee samples were analysed using liquid-liquid extraction followed by HPLC-DAD. The lipid contents of commercially roasted and ground Turkish coffee samples varied in the range of 14.32 ± 0.09 to 15.60 ± 0.09 g/100 g. The lipid contents of brewed Turkish coffee samples varied from 318 ± 2.00 to 571 ± 4.30 mg/100 mL. When compared within each commercial brand, dark roasted ground Turkish coffee samples had higher lipid contents. The average diterpene content in one cup of Turkish coffee sample was between 2.69 ± 0.28 and 13.58 ± 0.88 mg. The ranges of cafestol and kahweol contents in a cup were 1.4 ± 0.21 - 6.9 ± 0.65 mg and 1.28 ± 0.07 - 6.68 ± 0.28 mg, respectively. Within products of the same brand, the highest amount of oil was observed in dark roasted Turkish coffee beverages, and no significant differences were found in total diterpene, cafestol, and kahweol contents in coffee beverages among the different roasting levels. It is recommended that future studies perform more detailed investigations of the effect of roasting on the diterpene contents in Turkish coffees, and the impact of preparation parameters, as well as the presence of diterpene-derived compounds. [ABSTRACT FROM AUTHOR]

This study aimed to obtain polyunsaturated fatty acids by hydrolysis of coffee oil catalyzed by Candida rugosa lipase (CRL). The physicochemical properties and fatty acid profile of coffee oil were determined. Oleic (31.09%) and linoleic (51.80%) acids were the major fatty acids in coffee oil. A central composite design was carried out to assess the effect of lipase (0.1–0.5 wt%) and gum Arabic (0–3 wt%) concentrations on free fatty acid formation. Reactions were carried out in 50 mL stirred glass reactors at 37 °C for 2 h using 40 g of medium. CRL was an efficient catalyst of coffee oil hydrolysis, affording hydrolysis yields of 67.1–85.6%.The best predicted concentrations of lipase and gum Arabic were 0.1and 1.5 wt%, respectively. Under these conditions, the hydrolysis yield was 83.1% and the obtained hydrolysate was composed mainly of linoleic and oleic acids. Coffee oil as a source of omega-6 by enzymatic hydrolysis route [ABSTRACT FROM AUTHOR]

Copyright of Waste Forum is the property of Czech Environment Management Center (CEMC) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The valuable products that can be isolated from spent coffee ground (SCG) biomass consist of a high number of bioactive components, which are suitable for further application as raw materials in various production chains. This paper presents the potential value of the SCG obtained from large and local coffee beverage producers, for the production of valuable, biologically active products. Despite its high potential, SCG has not been utilized to its full potential value, but is instead discarded as waste in landfills. During its decomposition, SCG emits a large amount of CO2 and methane each year. The main novelty of our work is the implementation of sequential extraction with solvents of increased polarity that allows for the maximal removal of the available extractives. In addition, we have compared different extraction techniques, such as conventional and Soxhlet extraction, with more effective accelerated solvent extraction (ASE), which has seen relatively little use in terms of SCG extraction. By comparing these extraction methods and highlighting the key differences between them in terms of extraction yield and obtained extract composition, this work offers key insights for further SCG utilization. By using sequential and one-step accelerated solvent extraction, it is possible to obtain a significant number of extractives from SCG, with a yield above 20% of the starting biomass. The highest yield is for coffee oil, which is obtained with n-hexane ranging between 12% and 14% using accelerated solvent extraction (ASE) according to the scheme: n-hexane→ethyl acetate→60% ethanol. Using single-stage extraction, increasing the ethanol concentration also increases the total phenolic content (TPC) and it ranges between 18.7–23.9 Gallic acid equivalent (GAE) mg/g. The iodine values in the range of 164–174 using ASE and Soxhlet extraction shows that the hexane extracts contain a significant amount of unsaturated fatty acids; coffee oils with a low acid number, in the range of 4.74–6.93, contain few free fatty acids. The characterization of separated coffee oil has shown that it mainly consists of linoleic acid, oleic acid, palmitic acid, stearic acid and a small number of phenolic-type compounds.

The spontaneous precipitation of caffeine from black coffee bean extracts obtained by extraction with supercritical carbon dioxide has been found. This effect is observed for various types of coffee when using pressure values of the supercritical extractant on the order of 40–50 MPa. Two valuable products, caffeine and decaffeinated coffee oil, can be obtained by the simple centrifugation of CO2 extracts of coffee beans, which can be used in the food and cosmetic industries. [ABSTRACT FROM AUTHOR]

The higher demands of fossil energy usage are currently imbalance to its reserves. This issue will give a potency of fossil fuel scarcity that contributes on rising of its cost and disturbing economic stabilization in the future. It is desirable to find another resource which is sustainable and renewable to reduce the dependency on this resource. This study aimed to utilize the oil from instant coffee waste as biodiesel feedstocks. The coffee oil was extracted from instant-coffee waste by Soxhlet extractor and characterized its physical and chemical properties. The solvent extraction through the solid bed of coffee ground performed by five cycles interval using n-hexane as a solvent. Separation processing oil from its hydrocarbon solvent was in a rotary vacuum evaporator and the oil extract collected for further purposes. There was about 17.6% (on a dry weight basis) of coffee oil gained on 20 cycles of extraction. Analysis regarding its physicochemical properties reported that the crude oil has 0.89 g/mL of density, 43.82 mm2/s of kinematic viscosity, 44.47 mg KOH/g of acid value, and 176.40 mg KOH/g of saponification value. The fatty acids composition of the oil provided by GC-MS analyzer showed that unsaturated fatty acids contained, observed as trans-fatty acids rather than cis-fatty acids.

The performance of a fatty acid amide inhibitor synthesized from the coffee bagasse oil has been evaluated by electrochemical techniques such as potentiodynamic polarization curves, open circuit potential measurements, linear polarization resistance, and electrochemical impedance spectroscopy. Inhibitor concentrations included 0, 5, 10, 25, 50, and 100 ppm. Inhibitor efficiency was evaluated on an X70 steel in a CO2-saturated brine at 60°C. All the different techniques have indicated a decrease in the cathodic current density and inhibitor efficiency values as high as 96%. The inhibitor was chemically adsorbed on to the steel according to the analysis of the inhibitor adsorption process.

• Oil (16.8 %, w/w) was extracted from spent coffee grounds (SCG) with n -hexane. • Cupriavidus necator DSM-545 was cultivated on SCG and sunflower oils. • Cells accumulated 89.6 % (w/w) P(3HB- co -3 HV) (6.8 mol% 3 HV) when grown on SCG oil. • Synthesis of 3 HV likely occurs via the succinate-propionate metabolic pathway. 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. [ABSTRACT FROM AUTHOR]

Since it was first reported in Brazil, Asian soybean rust has been considered the most significant disease in the crop. Successive applications of fungicides during the crop cycle have been the most efficient control measures. Considering the occurrence of Phakopsora pachyrhizi populations with less sensitivity to the main recommended fungicide molecules, which results in lower control efficiency, as well as difficulties in obtaining new molecules, it is important that new tools be tested for integration into a management program. In field conditions, the efficiencies of one biological product based on Bacillus subtilis and another based on roasted coffee bean oils were studied in sequential and alternating applications with the fungicide pyraclostrobin + epoxiconazole. The application schedules of B. subtilis and chemical fungicide products in both trials reduced the area under the disease progress curve and increased the yield, the weight of 100 seeds, and the normalized difference vegetation index when compared to the control. B. subtilis and fungicides applied in sequence reduced the area under the disease progress curve 41% to 53% and 67% to 69% in the first and second assays, respectively. The applications of coffee oil alone or alternate with fungicide did not increased productivity compared to the control in the two fields. These results were obtained under conditions with a low intensity of disease, and therefore, different responses may be found under high intensity levels. These results allow us to suggest the use of products based on B. subtilis in soybean rust management programs along with chemical fungicides under low-medium disease pressure. [ABSTRACT FROM AUTHOR]

• Surface active nature of coffee oil has been evaluated with the help of surface tension analysis. • 1H NMR spectra of coffee oil showed the presence of n- hexane in the lipophilic region and chlorogenic acid in the hydrophilic region. • Molecular assembly of hydrophilic and lipophilic components present in the coffee solution was explained. • Coffee oil can be used as a natural surfactant over commercially available surfactants. Coffee oil is known to be food and therapeutic supplement, both. However, the surface active nature of the oil has not yet been investigated. The present research explored the surface active components in coffee oil, and those responsible for stability of microbubbles at the air–water interface, facilitating its surfactant behavior. The oil's performance was examined through surface tension analysis, foam formation, coalescence rate and foam characteristics (using coffee as a model beverage for foam characterization). These observations confirmed the suitability of coffee oil as a natural substitute for Tween series of surfactants. The 1H NMR and LC-MS/MS assessments revealed trigonelline, caffeic acid, caffeine, feruloyl quinic acid, di-caffeoyl quinic acid, quinic acid, coumaroyl quinic acid as polar constitutes in coffee oil. These constituents help in formation of the self-assembly (chlorogenic acid – hydrophilic head, hydrocarbon – hydrophobic tail), ultimately forming micelle in coffee. Coffee oil also aided maintenance of a well sustained foam in coffee, similar to other synthetic surfactants. [ABSTRACT FROM AUTHOR]

The performance of a fatty acid amide inhibitor synthesized from the coffee bagasse oil has been evaluated by electrochemical techniques such as potentiodynamic polarization curves, open circuit potential measurements, linear polarization resistance, and electrochemical impedance spectroscopy. Inhibitor concentrations included 0, 5, 10, 25, 50, and 100 ppm. Inhibitor efficiency was evaluated on an X70 steel in a CO2-saturated brine at 60°C. All the different techniques have indicated a decrease in the cathodic current density and inhibitor efficiency values as high as 96%. The inhibitor was chemically adsorbed on to the steel according to the analysis of the inhibitor adsorption process. [ABSTRACT FROM AUTHOR]

Green Coffea arabica L. seed oil (GCO) has been used as an active cosmetic ingredient in many skin care products, due to its composition and balance of fatty acids. On the other hand, while roasted coffee oil (RCO) is mainly used for imparting aroma in the food industry, there is no data available to suggest its safety in cell-based model systems. In this context, the present study aims to evaluate the chemical composition of GCO, RCO, and their correspondent polar fractions (PFs); and assess their cytotoxicity and antioxidant potential in vitro. RCO and RCO PF exhibited significantly higher amounts of phenolic compounds, when compared to both GCO and GCO PF. In the DPPH assay, after 5 min of incubation, RCO inhibited about 80% of radicals, while GCO only achieved half of this activity. Similar results were also obtained for their PFs. Upon exposure to GCO, no cytotoxic effects were observed, in fact, there were slight increments in cell proliferation. Nevertheless, cell exposure to RCO led to significant decreases in cell viability. Increases in the concentration of coffee oil PFs were associated with correspondent relevant increased cytotoxicity. Upon hydrogen peroxide-induced oxidative stress, neither GCO nor RCO treatment were effective in protecting cells. [ABSTRACT FROM AUTHOR]

Resource limits, environmental concerns and unstable petroleum costs have led to an increased effort to develop alternative liquid fuels. Purpose grown feedstocks are expensive and demand additional resources such as land and water. Spent coffee grounds (SCGs) are a good potential low-cost feedstock, however, processing times and costs must be lowered in order to be cost competitive with fossil fuels. In this work, we investigated the kinetics of oil extraction from SCGs to explore if current methods of oil extraction could be hastened and if an integrated process which couples oil extraction and conversion to biodiesel stages in one single step (in situ transesterification) was viable. Kinetics of oil extraction from SCGs using n -hexane as solvent was studied as a function of temperature, solvent to solid ratio and water content. We have found that oil extraction times could be as low as 10 min due to higher diffusion coefficients of oils from SCGs. Further, we demonstrate, for the first time, the successful in situ transesterification of SCGs using different concentrations of sodium hydroxide as a catalyst and methanol to oil mole ratios. Both of these outcomes show promise for lowering biodiesel production costs from SCGs, a ubiquitous waste product around the world. [ABSTRACT FROM AUTHOR]

Despite the convenience and extended shelf life of instant coffee, its aroma profile is less desirable compared to freshly brewed coffee. The objective of this study was to evaluate the effects of sucrose monopalmitate (P90), modified starch (MS) and Tween 80 on coffee aroma retention and release in oil-in-water emulsion matrices (coffee oil as the flavor matrix) and upon spiking into instant coffee, with an aim to enrich instant coffee aroma. The volatile profiles of P90-, MS- and Tween 80-stabilized coffee emulsions before, after freeze-drying and upon spiking into instant coffee were characterized with HS-SPME-GC-MS/FID and compared. The extent of volatile retention and release varied with the type of emulsifiers and volatile classes. Aldehydes and phenolic compounds levels in P90-stabilized coffee emulsions were 40% and 30% significantly lower compared to the control while their levels in Tween 80-stabilized coffee emulsion were 8% and 38% lower compared to the control respectively. Phenolic compounds levels in MS-stabilized coffee emulsion were 13% significantly lower compared to the control. Volatile retention remained after freeze-drying for P90- and Tween 80-stabilized coffee emulsions where total volatile levels were 12% and 25% significantly lower compared to the controls, respectively. The total volatiles levels of instant coffees spiked with P90- and MS-stabilized coffee emulsions were higher compared to the blank and spiking with the controls. The trend was reversed when Tween 80-stabilized coffee emulsion was spiked. Therefore, P90- and MS-stabilized coffee emulsions exhibited some extent of controlled aroma release and could be utilized for instant coffee aroma enrichment. [ABSTRACT FROM AUTHOR]

The aim of this paper was to investigate the possibility of obtaining oil from spent coffee grounds, which are left behind after the coffee is prepared, as the potential feedstock for biodiesel production. The effect of process parameters, such as are the type of solvent, the ratio of spent coffee grounds/solvent and the extraction time on oil yielded from coffee grounds was examined. The oil was obtained by maceration and extraction in the Soxhlet apparatus. The obtain results show that the spent coffee grounds could be used as an alternative raw material for biodiesel production, because it contains a significant amount of oil that can be extracted. The oil yield depends on the extraction (maceration) process parameters. The maximum oil yield obtained by the Soxhlet extraction with the n-hexane for the period of 5 h was 11.85% (the weight percentage of oil on dry mater), whereas with petroleum ether the oil yield was slightly lower and amounted to 10.44%. The yield of the oil extracted by maceration increases with the decrease of spent coffee grounds/solvent ratio from 1/3 to 1/7 g/cm3, and other parameters being constant. The oil yield increases with the duration of the maceration. Greater oil yield, ranging from 3 to 8.5%, can be obtained with n-hexane compared to the extraction with petroleum ether. Furthermore, n-hexane is less volatile and flammable, compared to petroleum ether, so it is more convenient to use.

The caffeine solubility in supercritical CO2 was studied by assessing the effects of pressure and temperature on the extraction of green coffee oil (GCO). The Peng-Robinson¹ equation of state was used to correlate the solubility of caffeine with a thermodynamic model and two mixing rules were evaluated: the classical mixing rule of van der Waals with two adjustable parameters (PR-VDW) and a density dependent one, proposed by Mohamed and Holder² with two (PR-MH, two parameters adjusted to the attractive term) and three (PR-MH3 two parameters adjusted to the attractive and one to the repulsive term) adjustable parameters. The best results were obtained with the mixing rule of Mohamed and Holder² with three parameters.

En el presente trabajo se realiza la extracción de aceite de café mediante el método de extrusión. En dicho proceso se obtienen dos productos: el aceite de café y la torta. Para tal propósito se utilizó café tostado, el cual se caracteriza por poseer una elevada cantidad de compuestos odoríferos; es importante saber que un criterio significativo en la valoración de la calidad del café, es su aroma. Al extraer el aceite, una parte significativa del contenido aromático del café tostado, que varía según el método de extracción usado, sale con él. Es asI como se obtiene un aceite filo con una alta carga volátil, el cual presenta características organolépticas favorables. Al segundo producto que se obtiene, se le realizó análisis físico-químico en aras de mostrar sus bondades y propiedades particulares, y de acuerdo a los resultados obtenidos, es un producto que presenta un amplio potencial de utilización.

This work illustrates morpholine assisted transesterification of crude canola oil, corn oil and coffee oil (extracted from spent coffee grounds) using NaOH as a homogeneous base catalyst. Addition of morpholine resulted in a two-fold enhancement in kinetics of transesterification. The properties of the biodiesel final product were evaluated by fuel standard tests and the results were compared with ASTM D6751 standards. Biodiesel produced from canola, coffee and corn oils was found to have a high cetane number (52.5–55.1) and good flash point (140 °C). [ABSTRACT FROM AUTHOR]

In the present work, the extraction of oil from roasted coffee beans using supercritical carbon dioxide ( SC CO 2 ) under different conditions of pressure (15–30 MPa) and temperature (40–60 °C) was studied. A central composite experimental design was employed in order to establish the effect of these parameters on the yield and fatty acids composition that was determined by gas chromatography with flame ionization detector (GC-FID). The aroma was analyzed by headspace solid phase microextraction (HS-SPME). The optimum oil yield was 8.9%, obtained at 33.1 MPa and 35.9 °C. The main fatty acids identified were palmitic (46.1%), linoleic (32.9%), oleic (8.0%), stearic (6.6%) and arachidic (1.9%). The volatile compounds of the coffee oil belong mainly to the family of furans and pyrazines, which maintain the particular features of the roasted coffee. This fact makes the coffee oil attractive to be used in the food and/or cosmetic industry. [ABSTRACT FROM AUTHOR]

This study aimed the encapsulation of coffee oil flavor and optimizing the process conditions which affect the encapsulation efficiency (EE). Oil was extracted from roasted Coffea arabica , (Yrigachefe, Ethiopia) using supercritical carbon dioxide (Sc–CO 2 ). Then, the extracted oil was encapsulated by polyethyleneglycol (PEG) using particles from gas-saturated solutions (PGSS) process. Process parameters which affect the EE such as, temperature (T, 40–50 °C), pressure (P, 200–300 bar) and polymer-oil ratios (R, 5:1–10:1 g/g) were optimized via Box Behnken design (BBD). The optimal conditions were (T, 40.0 °C, P, 260.14 bar and R, 6.57:1 g/g) with a maximum EE of 79.78%. The encapsulated oil showed peroxide value of 4.56 meq peroxide/kg oil after 12 weeks of storage. Less than 2% loss of fatty acid composition was observed after encapsulation. Moreover, flavor profiles of particles obtained using optimal condition showed very good preservation of flavors. Therefore, microencapsulation using PGSS process could be employed for production of freely flowing powdered particles that can be used in food processing industries. [ABSTRACT FROM AUTHOR]