Functional properties of coffee and coffee by-products

Biogas Potential of Coffee Processing Waste in Ethiopia

Primary coffee processing is performed following the dry method or wet method. The dry method generates husk as a by-product, while the wet method generates pulp, parchment, mucilage, and waste water. In this study, characterization, as well as the potential of husk, pulp, parchment, and mucilage for methane production were examined in biochemical methane potential assays performed at 37 °C. Pulp, husk, and mucilage had similar cellulose contents (32%). The lignin contents in pulp and husk were 15.5% and 17.5%, respectively. Mucilage had the lowest hemicellulose (0.8%) and lignin (5%) contents. The parchment showed substantially higher lignin (32%) and neutral detergent fiber (96%) contents. The mean specific methane yields from husk, pulp, parchment, and mucilage were 159.4 ± 1.8, 244.7 ± 6.4, 31.1 ± 2.0, and 294.5 ± 9.6 L kg−1 VS, respectively. The anaerobic performance of parchment was very low, and therefore was found not to be suitable for anaerobic fermentation. It was estimated that, in Ethiopia, anaerobic digestion of husk, pulp, and mucilage could generate as much as 68 × 106 m3 methane per year, which could be converted to 238,000 MWh of electricity and 273,000 MWh of thermal energy in combined heat and power units. Coffee processing facilities can utilize both electricity and thermal energy for their own productive purposes.

Neutron activation analysis of major and trace elements in Arabica and Robusta coffee beans samples consumed in Algeria

The Algerian neutron activation analysis laboratory is highly involved in nutrition applications in the framework of research activities using the Es-Salam research reactor. The main objective of this work is to contribute, by using nuclear analytical techniques, for studying a large number of natural food samples consumed in Algeria related to nutrition and human health. The present study focuses on the analysis of the most popular beans consumed worldwide, namely, the coffee species of Arabica and Robusta, based on the international markets. Chemical content of samples was assessed by instrumental neutron activation analysis (INAA) and k 0-INAA techniques, through the irradiation of samples during 6 h at a thermal neutron flux of 4.5×1013cm−2s−1 of Es-Salam research reactor. A total of 17 elements were assessed such as, (Br, Ca, Ce, Co, Cr, Cs, Fe, K, La, Na, Rb, Sc, Sm, Sr, Zn, Lu and Th) obtained by using INAA and k 0-INAA methods, While we used the radiochemical neutron activation analysis (RNAA and k 0-RNAA) to determine Selenium at low level concentrations, the accuracy of the method was evaluated by analyzing CRM and SRM. QC/QA was evaluated by using the statistical parameter U-score. Results were compared with those obtained for samples from Brazilian, Caribbean, Indian and Kenyan coffee beans reported in the literature. The daily intake of essentials and toxic elements was determined and compared with the recommended values. The probable cumulative intake of toxic elements was found to be well below the tolerance limits.

Valorizing coffee pulp by-products as anti-inflammatory ingredient of food supplements acting on IL-8 release

Coffee is the second traded food commodity in the world. Beyond roasted seeds, the most part of the original fruit -and in particular pulp- is discarded as waste, with severe environmental and economic consequences in many developing countries. Our research focused on developing an eco-friendly extraction protocol of phytocomplexes from coffee pulp and evaluating their bioactivity and beneficial effects to human health as food supplements. Antioxidant activity assays (Folin-Ciocalteu and DPPH assays) were adopted to select the most effective extraction technique and results show antioxidant activity of coffee pulp extracts. After analysis of cytotoxicity on human epithelial gastric cells, measurements of IL-8 release of treated or pre-treated cells were performed. Results showed that the use of soft technical equipment and sustainable solvents (i.e. maceration process, aqueous extraction) can extract phytocomplexes with antioxidant properties. Moreover, IL-8 measurements showed impairment of this chemokine release at concentrations that may be reached in vivo in the gastrointestinal tract, following consumption of reasonable amount of extract. Pre-treatments analysis demonstrated the ability of coffee pulp extracts to prevent IL-8 release by gastric epithelial cells. Chemical evaluation performed by liquid chromatography mass spectrometry showed that quinic acid derivatives are abundant in coffee pulp extract together with procyanidins derivatives: those compounds might be responsible for the high biological activity. This evidence supports future applications of coffee pulp extracts as food supplement with high added value, starting from a waste that can be valorized through simple yet efficient extraction methods.

Performance of plasma trigonelline as a marker of coffee consumption in an epidemiologic setting

Background

Coffee is a widely consumed beverage, and studies suggest that drinking coffee has beneficial health effects. The phytohormone trigonelline is present in large amounts in coffee beans, and circulating concentrations of trigonelline have been shown to be positively related to dietary intake of coffee and to increase significantly after the consumption of a bolus dose of coffee.

Objective

We cross-sectionally investigated the utility of plasma trigonelline as a marker of coffee consumption in an epidemiologic setting. We secondarily investigated if coffee intake is related to plasma concentrations of vitamin B-3 (niacin) forms.

Design

In a Norwegian cohort of 3503 participants, we combined questionnaire data on the number of cups of coffee consumed per day with plasma trigonelline to evaluate trigonelline as a marker of coffee intake. The suitability of plasma trigonelline to discriminate those not consuming from those consuming coffee was investigated by receiver operating characteristic (ROC) analysis. Plasma collected at 2 time points 1 y apart was used to determine the within-person reproducibility of trigonelline.

Results

We found that plasma trigonelline concentrations increased strongly with increasing amounts of coffee consumed. ROC analysis showed that trigonelline had an area under the curve of 0.92 (95% CI: 0.90, 0.94) for distinguishing coffee abstainers from coffee drinkers. Plasma trigonelline had a good within-person reproducibility (0.66; 95% CI: 0.64, 0.68) for samples collected 1 y apart. The amount of coffee consumed was not associated with plasma concentrations of the niacin vitamers nicotinamide and N1-methylnicotinamide.

Conclusions

Plasma trigonelline performs well as a marker of coffee intake. Data used in this study were derived from the clinical trial registered at www.clinicaltrials.gov as NCT00354081.

Rust and Thinning Management Effect on Cup Quality and Plant Performance for Two Cultivars of Coffea arabica L

Beverage quality is a complex attribute of coffee ( Coffea arabica L.). Genotype (G), environment (E), management (M), postharvest processing, and roasting are all involved. However, little is known about how G × M interactions influence beverage quality. We investigated how yield and coffee leaf rust (CLR) disease (caused by Hemileia vastatrix Berk. et Br.) management affect cup quality and plant performance, in two coffee cultivars. Sensory and chemical analyses revealed that 10 of 70 attributes and 18 of 154 chemical volatile compounds were significantly affected by G and M. Remarkably, acetaminophen was found for the first time in roasted coffee and in higher concentrations under more stressful conditions. A principal component analysis described 87% of the variation in quality and plant overall performance. This study is a first step in understanding the complexity of the physiological, metabolic, and molecular changes in coffee production, which will be useful for the improvement of coffee cultivars.

Effect of coffee roasting on in vitro α-glucosidase activity: Inhibition and mechanism of action

In vitro α-glucosidase inhibitory activity of unroasted, and medium, dark and very dark roasted robusta coffee was studied. Coffee extracts significantly inhibited the enzyme activity in a dose-dependent way. The inhibitory activity was well correlated with the degree of roast. Coffee components were separated by gel permeation chromatography into low (1 < MW < 6 kDa), intermediate (15 < MW < 60 kDa) and high (MW > 100 kDa) molecular weight fractions, which were analyzed for the α-glucosidase inhibitory capacity. Only fractions obtained from dark and very dark roasted coffee exhibited inhibitory effect. When the same fraction was obtained from coffee presenting different roasting degree, changes in α-glucosidase inhibition extent were observed. This was attributed to compositional changes within each fraction as induced by roasting. Coffee extracts and their fractions exerted a mixed-type to competitive inhibition against α-glucosidase and these mechanisms are consistent with the complexity of coffee composition.

Increasing the loading rate of continuous stirred tank reactor for coffee husk and pulp: Effect of trace elements supplement

In this study, the anaerobic performance and stability of coffee husk and pulp with and without trace element (TE) supplement was investigated, using 20 L mesophilic continuous stirred tank reactors for 140 days of experiment (DOE). The TE was cocktail of trace metals composed of Fe, Ni, Zn, Co, Mn, Mo, Se W and B. The organic loading rate (OLR) was increased stepwise from 2.5 (HRT = 40 d) to 6.0 kg VS m^-3 d^- 1(HRT = 16.7 d). The highest methane productivity from pulp with and without TE was 1.272 and 0.965 m³ m^-3 d^-1 at an OLR of 6.0 and 5.0 kg VS m^-3 d^-1; while the husks performed 0.895 and 0.795 m³ m^-3 d^-1 respectively, both at an OLR of 6.0 kg VS m^-3 d^-1. The specific methane yield (SMY) of pulp (at OLR = 5 kg VS m^-3 d^-1) with and without TEs was 217.9 ± 4.7 and 193.1 ± 8.2 L kg^-1 VS; while husk yielded 149.2 ± 6.0 and 132.5 ± 4.9 L kg^-1 VS, respectively. The effect of TEs on SMY was statistically significant (p < 001) at higher OLRs (5.0 - 6.0 kg VS m^-3 d^-1). The TEs improved the anaerobic stability through an optimum alkalinity ratio (VFA/TIC < 0.3) and suppressed the accumulation of volatile fatty acids. Mono digestion of husks and pulp are prone to lack Mo, Zn, Ni and Fe in long-term anaerobic fermentation. Further studies on co-digestion of husk/pulp with animal manure and dry fermentation helps to efficiently use this biomass resource.

Hydroxycinnamic acids profiling, in vitro evaluation of total phenolic compounds, caffeine and antioxidant properties of coffee imported, roasted and consumed in Algeria

BACKGROUD: Coffee is the most popular beverages consumed worldwide. It is an important source of antioxidants that can inhibit harmful effects of free radicals. OBJECTIVE: Comparative analysis of imported, roasted and consumed coffee in Algeria. METHODS: Investigation of the hydroxycinnamic acids profile of dark roasted coffee beans UHPLC-DAD-ESI-MSn analysis and in vitro evaluation of total phenolic compounds (TPC), caffeine and antioxidant activity using DPPH, ABTS, reducing power and phosphomolybdum methods in green and roasted Arabica and Robusta coffees beans and in coffee brews (Moka, Turk and Filter) prepared from a blend of Arabica and Robusta 20:80. RESULTS: Arabica and Robusta dark roasted beans had similar chromatographic profiles, being rich in caffeoylquinic acid and feruloylquinic acid isomers. Compared to green beans, roasted coffee beans had higher amounts of TPC while caffeine drastically decreased. The antioxidant activity increased after roasting, while the reducing activity was decreased. Filter coffee showed the highest levels of TPC and caffeine (0.69±0.05 g GAE/100 g, 0.96±0.08 mg/g respectively), which exhibits the higher reducing activity for the iron (III) and molybdate with 0.45±0.01 g GAE/100 g, 134.30±2.38 mg GAE/100 g, respectively. However, the Turk coffee exhibited the highest antiradical activity with 73.34% and 83.63% towards DPPH and ABTS, respectively. Significant correlations were recorded between TPC, caffeine and reducing power (r = 0.89) and (r = 0.97) respectively. CONCLUSION Despite the high roasting degree applied to green coffee beans, the consumed coffee constitute an important source of chlorogenic acids and its derivatives with high antioxidant potential that are beneficial for human health.

Molecular mechanisms of the anti-obesity effect of bioactive compounds in tea and coffee

Obesity is a serious health problem in adults and children worldwide. However, the basic strategies for the management of obesity (diet, exercise, drugs and surgery) have limitations and side effects. Therefore, many researchers have sought to identify bioactive components in food. Tea and coffee are the most frequently consumed beverages in the whole world. Their health benefits have been studied for decades, especially those of green tea. The anti-obesity effect of tea and coffee has been studied for at least ten years. The results have shown decreased lipid accumulation in cells via the regulation of the cell cycle during adipogenesis, changes in transcription factors and lipogenesis-related proteins in the adipose tissue of animal models, and decreased body weight and visceral fat in humans. Tea and coffee also influence the gut microbiota in obese animals and humans. Although the anti-obesity mechanism of tea and coffee still needs further clarification, they may have potential as a new strategy to prevent or treat obesity.

Robustanoids A and B, two novel pyrrolo[2,3-b]indole alkaloids from Coffea canephora: isolation and total synthesis

Two novel pyrrolo[2,3-b]indole alkaloids were isolated from Coffea canephora beans; their structures were confirmed by total synthesis.

Characterization of Anti-Ice Nucleation Activity of the Extract from Coffee Refuse

　The supercooling-facilitating (SCF) activities, that is, the anti-ice nucleation activity of the hot water extracts from five types of processed food refuse was examined. The extract with the highest activity among five hot water extracts was coffee refuse, showing 1.50℃ of SCF activity at a final concentration of 0.1 mg/ml. From the hot water extract of coffee refuse, the coffee refuse extract containing various polyphenols was prepared by the ultrafiltration (less than MWCO 10,000), a solvent fractionation of ethyl acetate. The yield of coffee refuse extract was 0.9% (w/w) from dried coffee refuse. The SCF activity of the coffee refuse extract at a final concentration of 1.0 mg/ml was 4.2℃. HPLC analysis of the coffee refuse extract showed that caffeine and chlorogenic acid, which are major components of coffee, could be found at 173 and 62.3 µg/ml, respectively. However, the SCF activities of both compounds (0.70 and 1.06℃) at a final concentration of 0.1 mg/ml were lower than those of ferulic acid and coumaric acid, respectively at 3.40 and 2.35℃. This is the first report to our knowledge on the SCF activity of caffeine. The SCF activity of caffeine at a final concentration of 1.0 mg/ml was 2.3℃. The specificity of caffeine against various ice nuclei containing calcium oxalate, 9-fluorenon, and ice nucleating bacteria was examined. Caffeine at a final concentration of 1.0 mg/ml could inhibit the ice nucleation activity of calcium oxalate, and Pseudomonas fluorescens KUIN-1 at the same level that of as silver iodide. From these results, it was suggested that the extract could be able to be applied to the field to control the frost damage of the vegetables and that the harvested vegetables might be stored unfrozen even at 0℃ or less.

Effects of coffee processing residues on anaerobic microorganisms and corresponding digestion performance

The objective of this study was to delineate the effects of different coffee processing residues on the anaerobic microbes and corresponding digestion performance. The results elucidated that mucilage-rich feed enhanced the accumulation of methanogens, which consequently led to better digestion performance of biogas production. Fifty percent more methane and up to 3 times more net energy (heat and electricity) output were achieved by the digestion of the mucilage-rich feed (M3). The microbial community and statistical analyses further elucidated that different residues in the feed had significant impact on microbial distribution and correspondingly influenced the digestion performance.

The Use of Partial Least Square Regression and Spectral Data in UV-Visible Region for Quantification of Adulteration in Indonesian Palm Civet Coffee

Asian palm civet coffee or kopi luwak (Indonesian words for coffee and palm civet) is well known as the world's priciest and rarest coffee. To protect the authenticity of luwak coffee and protect consumer from luwak coffee adulteration, it is very important to develop a robust and simple method for determining the adulteration of luwak coffee. In this research, the use of UV-Visible spectra combined with PLSR was evaluated to establish rapid and simple methods for quantification of adulteration in luwak-arabica coffee blend. Several preprocessing methods were tested and the results show that most of the preprocessing spectra were effective in improving the quality of calibration models with the best PLS calibration model selected for Savitzky-Golay smoothing spectra which had the lowest RMSECV (0.039) and highest RPD_cal value (4.64). Using this PLS model, a prediction for quantification of luwak content was calculated and resulted in satisfactory prediction performance with high both RPD _p and RER values.

Chlorogenic acid from coffee beans: evaluating the evidence for a blood pressure-regulating health claim

The consumption of coffee has been associated with a number of health benefits, including a reduced risk of cardiovascular disease. Hypertension is an important risk factor for adverse cardiovascular events. Coffee may help reduce blood pressure (BP) in humans, which might be attributable to its polyphenolic compound, chlorogenic acid. The high incidence of hypertension among Canadians underscores the need for new and effective strategies to reduce BP. Dietary interventions may constitute such a strategy, but consumers need to be informed about which foods are most effective for regulating BP. To guide healthy eating, Health Canada permits the use of health claims on the labels of foods that confer health benefits. Currently, there is only one health claim for BP regulation. Additional health claims for foods that assist in BP regulation are therefore warranted. This review provides background information on chlorogenic acid and examines the evidence regarding the use of chlorogenic acid for BP regulation in the context of Health Canada's health claims framework.

Antiproliferative and cytotoxic effects of green coffee and yerba mate extracts, their main hydroxycinnamic acids, methylxanthine and metabolites in different human cell lines

This work aimed at studying the effects of green coffee bean (GCBE) and yerba mate (YME) extracts, their main phenolic components (5-caffeoylquinic acid, 5-CQA; 3,5-dicaffeoylquinic acid, 3,5-DCQA) and metabolites (ferulic acid, FA; caffeic acid, CA; dihydrocaffeic acid, DHCA; and dihydroferulic acid, DHFA) along with caffeine (CAF) on the viability and proliferation of different human cell lines. Extracts (10-1000 μg/mL) and standards (10-1000 μM) were assayed in colon (Caco-2), lung (A549), oesophageal (OE-33), urinary bladder (T24) human carcinoma cells, and a non-cancer cell line (CCD-18Co). YME significantly reduced viability of cancer cells at all assayed concentrations, the higher doses also reducing cell proliferation. GCBE effects on cell viability were more effective at 100 and 1000 μg/mL, showing modest effects on cell proliferation. The highest doses of 5-CQA and 3,5-DCQA reduced cell viability and proliferation in all cell lines, whereas FA, DHCA and DHFA had lower and variable effects. Caffeine had no effect. Dietary-attainable concentrations (0.1, 1 and 10 μg/mL) of YME were tested for cytotoxicity and reactive oxygen species generation, showing no cytotoxic effect. Low concentrations of all tested compounds were non-cytotoxic to CCD-18Co cells.

CONCLUSION

YME and to a lower degree GCBE, their phenolic components and metabolites may decrease cancer cell viability and proliferation.

Development of polylactic acid nanocomposite films reinforced with cellulose nanocrystals derived from coffee silverskin

Bio-nanocomposite films based on polylactic acid (PLA) matrix reinforced with cellulose nanocrystals (CNCs) were developed using a twin-screw extruder. The CNCs were extracted from coffee silverskin (CS), which is a by-product of the coffee roasting process. They were extracted by alkali treatment followed by sulfuric acid hydrolysis. They were used as reinforcing agents to obtain PLA/CNC nanocomposites by addition at different concentrations (1%, 3%, and 5% CNCs). Morphological, tensile, and barrier properties of the bio-nanocomposites were analyzed. The tensile strength and Young's modulus increased with both 1% and 3% CNCs. The water vapor permeability decreased gradually with increasing addition of CNCs up to 3% and good oxygen barrier properties were found for all nanocomposites. These results suggest that CNCs from CS can improve the physical properties of PLA-based biopolymer film. The developed PLA/CNC bio-nanocomposite films can potentially be used for biopolymer materials with enhanced barrier and mechanical properties.

Chemical Characterization of Potentially Prebiotic Oligosaccharides in Brewed Coffee and Spent Coffee Grounds

Oligosaccharides are indigestible carbohydrates widely present in mammalian milk and in some plants. Milk oligosaccharides are associated with positive health outcomes; however, oligosaccharides in coffee have not been extensively studied. We investigated the oligosaccharides and their monomeric composition in dark roasted coffee beans, brewed coffee, and spent coffee grounds. Oligosaccharides with a degree of polymerization ranging from 3 to 15, and their constituent monosaccharides, were characterized and quantified. The oligosaccharides identified were mainly hexoses (potentially galacto-oligosaccharides and manno-oligosaccharides) containing a heterogeneous mixture of glucose, arabinose, xylose, and rhamnose. The diversity of oligosaccharides composition found in these coffee samples suggests that they could have selective prebiotic activity toward specific bacterial strains able to deconstruct the glycosidic bonds and utilize them as a carbon source.

Valorisation of Biowastes for the Production of Green Materials Using Chemical Methods

With crude oil reserves dwindling, the hunt for a sustainable alternative feedstock for fuels and materials for our society continues to expand. The biorefinery concept has enjoyed both a surge in popularity and also vocal opposition to the idea of diverting food-grade land and crops for this purpose. The idea of using the inevitable wastes arising from biomass processing, particularly farming and food production, is, therefore, gaining more attention as the feedstock for the biorefinery. For the three main components of biomass-carbohydrates, lipids, and proteins-there are long-established processes for using some of these by-products. However, the recent advances in chemical technologies are expanding both the feedstocks available for processing and the products that be obtained. Herein, this review presents some of the more recent developments in processing these molecules for green materials, as well as case studies that bring these technologies and materials together into final products for applied usage.

Utilization of inulin-containing waste in industrial fermentations to produce biofuels and bio-based chemicals

Inulins are polysaccharides that belong to an important class of carbohydrates known as fructans and are used by many plants as a means of storing energy. Inulins contain 20 to several thousand fructose units joined by β-2,1 glycosidic bonds, typically with a terminal glucose unit. Plants with high concentrations of inulin include: agave, asparagus, coffee, chicory, dahlia, dandelion, garlic, globe artichoke, Jerusalem artichoke, jicama, onion, wild yam, and yacón. To utilize inulin as its carbon and energy source directly, a microorganism requires an extracellular inulinase to hydrolyze the glycosidic bonds to release fermentable monosaccharides. Inulinase is produced by many microorganisms, including species of Aspergillus, Kluyveromyces, Penicillium, and Pseudomonas. We review various inulinase-producing microorganisms and inulin feedstocks with potential for industrial application as well as biotechnological efforts underway to develop sustainable practices for the disposal of residues from processing inulin-containing crops. A multi-stage biorefinery concept is proposed to convert cellulosic and inulin-containing waste produced at crop processing operations to valuable biofuels and bioproducts using Kluyveromyces marxianus, Yarrowia lipolytica, Rhodotorula glutinis, and Saccharomyces cerevisiae as well as thermochemical treatments.

Isolation of polyphenols from spent coffee grounds and silverskin by mild hydrothermal pretreatment

In this study, a new method for isolation of polyphenols (PP) from spent coffee grounds (SCG) and coffee silverskin (CS) is described. The method consisted of a mild hydrothermal pretreatment at 120°C, for 20 min, using a liquid-to-solid ratio of 20 mL/g. PP (determined as gallic acid equivalents, GAE) were the most abundant components in the extracts produced by this method, corresponding to 32.92 mgGAE/gSCG and 19.17 mgGAE/gCS, among which flavonoids corresponded to 8.29 and 2.73 mg quercetin equivalents/g of SCG and CS, respectively. Both extracts presented antioxidant activity but the results were higher for SCG extract, probably due to the highest content of PP present. Negligible effects (less than 1% solubilization) were caused by the hydrothermal pretreatment on cellulose, hemicellulose, and protein fractions of these materials. Some mineral elements were present in the extracts, with potassium being the most abundant. Hydrothermal pretreatment under mild conditions was demonstrated to be an efficient method to recover antioxidant PP from coffee residues.

An Investigation into Spent Coffee Waste as a Renewable Source of Bioactive Compounds and Industrially Important Sugars

Conventional coffee brewing techniques generate vast quantities of spent espresso grounds (SEGs) rich in lignocellulose and valuable bioactives. These bioactive compounds can be exploited as a nutraceutical or used in a range of food products, while breakdown of lignocellulose generates metabolizable sugars that can be used for the production of various high-value products such as biofuels, amino acids and enzymes. Response surface methodology (RSM) was used to optimize the enzymatic saccharification of lignocellulose in SEGs following a hydrothermal pretreatment. A maximum reducing sugar yield was obtained at the following optimized hydrolysis conditions: 4.97 g of pretreated SEGs, 120 h reaction time, and 1246 and 250 µL of cellulase and hemicellulase, respectively. Industrially important sugars (glucose, galactose and mannose) were identified as the principal hydrolysis products under the studied conditions. Total flavonoids (p = 0.0002), total polyphenols (p = 0.03) and DPPH free-radical scavenging activity (p = 0.004) increased significantly after processing. A 14-fold increase in caffeine levels was also observed. This study provides insight into SEGs as a promising source of industrially important sugars and polyphenols.

Bioactives of coffee cherry pulp and its utilisation for production of Cascara beverage

Coffee cherry pulp is a by-product obtained during coffee production. Coffee cherry pulp contains considerable amounts of phenolic compounds and caffeine. An attempt to produce Cascara, a refreshing beverage, has been made. Six dried coffee pulp samples and a beverage called Cascara produced in Switzerland out of one of those samples were investigated. Aqueous extraction of coffee pulps revealed a content of total polyphenols between 4.9 and 9.2mg gallic acid equivalents (GAE)/gDM. The antioxidant capacity was between 51 and 92μmol Trolox equivalents (TE)/gDM as measured by the assay with ABTS radical. Bourbon variety from Congo and maragogype variety showed highest caffeine contents with 6.5 and 6.8mg/gDM. In all samples chlorogenic acid, protocatechuic acid, gallic acid and rutin were present. The beverage Cascara contained 226mg/L of caffeine and 283mgGAE/L of total polyphenols whereas antioxidant capacity amounted to 8.9mmol TE/L.

Phytochemical Composition, Antioxidant Activity, and the Effect of the Aqueous Extract of Coffee (Coffea arabica L.) Bean Residual Press Cake on the Skin Wound Healing

The world coffee consumption has been growing for its appreciated taste and its beneficial effects on health. The residual biomass of coffee, originated in the food industry after oil extraction from coffee beans, called coffee beans residual press cake, has attracted interest as a source of compounds with antioxidant activity. This study investigated the chemical composition of aqueous extracts of coffee beans residual press cake (AE), their antioxidant activity, and the effect of topical application on the skin wound healing, in animal model, of hydrogels containing the AE, chlorogenic acid (CGA), allantoin (positive control), and carbopol (negative control). The treatments' performance was compared by measuring the reduction of the wound area, with superior result (p < 0.05) for the green coffee AE (78.20%) with respect to roasted coffee AE (53.71%), allantoin (70.83%), and carbopol (23.56%). CGA hydrogels reduced significantly the wound area size on the inflammatory phase, which may be associated with the well known antioxidant and anti-inflammatory actions of that compound. The topic use of the coffee AE studied improved the skin wound healing and points to an interesting biotechnological application of the coffee bean residual press cake.

Phytochemical overview and medicinal importance of Coffea species from the past until now

Coffea (coffee) species are grown in almost all countries along the Equator. Many members of the genus have a large production history and an important role both in the global market and researches. Seeds (Coffeae semen) are successfully used in food, cosmetic, and pharmaceutical industries due to its caffeine and high polyphenol content. Nowadays, the three best-known coffee species are Arabic (Coffea arabica L.), Robusta (Coffea robusta L. Linden), and Liberian coffees (Coffea liberica Hiern.). Even though, many records are available on coffee in scientific literature, wild coffee species like Bengal coffee (Coffea benghalensis Roxb. Ex Schult.) could offer many new opportunities and challenges for phytochemical and medical studies. In this comprehensive summary, we focused on the ethnomedicinal, phytochemical, and medical significance of coffee species up to the present.

Comparison of antioxidant, antimicrobial activities and chemical profiles of three coffee (Coffea arabica L.) pulp aqueous extracts

Background

This study explored the bioactivities and nutrient compositions of coffee (Coffea Arabica L.) pulp which was prepared in three different ways [Coffee Pulp Extracts (CPE) 1–3].

Methods

The coffee pulp was prepared in three different ways by distinct selecting and freezing processes. The nutritional values, polyphenol contents, antioxidant activity, and antibacterial properties of the coffee pulp as well as the characterization of the active ingredients by liquid chromatography-electrospray ionization-quadrupole-time-of-flight mass spectrometry (LC-ESI-Q-TOF-MS) were evaluated.

Results

The chemical profiles of three aqueous extracts were compared and characterized using LC-ESI-QTOF-MS. They showed slightly different nutrient compositions. The total phenolic content was highest in CPE1, and decreased in the following order: CPE1 > CPE2 > CPE3. Among the CPEs tested, CPE1 showed the most potent antioxidant activity with IC₅₀ 18 μg/mL and 82 μg/mL by 2,2’-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) and 1,1-diphenyl-2-picryl-hydrazyl assay, respectively. Chlorogenic acid and caffeine were the most prominent in CPE1 and it contained more compounds than the others. Moreover, CPE1 demonstrated antibacterial activity against both gram-positive (Staphylococcus aureus and Staphylococcus epidermidis) and gram-negative bacteria (Pseudomonas aeruginosa and Escherichia coli).

Conclusion

These findings indicated that CPE1 has powerful nutrients with antioxidant and antibacterial properties—the potency of which is impacted by the preparation process.

Antioxidant Effect of Extracts from the Coffee Residue in Raw and Cooked Meat

The residue of ground coffee obtained after the brewing process (spent coffee) still contains various functional components with high antioxidant capacity and health benefits, but no attempts have been made to use it as a resource to produce value-added food ingredients. This study evaluates the antioxidant activity of ethanol or hot water extracts from the residues of coffee after brewing. An extraction experiment was carried out using the conventional solid–liquid methods, including ethanol and water as the extraction media at different temperatures and liquid/solid ratios. The antioxidant activity of extracts was tested for total phenolic compound (TPC), 2,2-diphenyl-1-picrylhydrazyl (DPPH), and 2-thiobarbituric acid reactive substances (TBARS) using oil emulsion and raw/cooked meat systems. The DPPH radical scavenging activity of the ethanol extracts with heating (HEE) and without heating (CEE) were higher than that of the hot water extracts (WE). The highest DPPH value of HEE and CEE at 1000 ppm was 91.22% and 90.21%, respectively. In oil emulsion and raw/cooked systems, both the water and ethanol extracts had similar antioxidant effects to the positive control (BHA), but HEE and CEE extracts showed stronger antioxidant activities than WE extract. These results indicated that the ethanol extracts of coffee residue have a strong antioxidant activity and have the potential to be used as a natural antioxidant in meat.

Growth, ethanol production, and inulinase activity on various inulin substrates by mutant Kluyveromyces marxianus strains NRRL Y-50798 and NRRL Y-50799

Economically important plants contain large amounts of inulin. Disposal of waste resulting from their processing presents environmental issues. Finding microorganisms capable of converting inulin waste to biofuel and valuable co-products at the processing site would have significant economic and environmental impact. We evaluated the ability of two mutant strains of Kluyveromyces marxianus (Km7 and Km8) to utilize inulin for ethanol production. In glucose medium, both strains consumed all glucose and produced 0.40 g ethanol/g glucose at 24 h. In inulin medium, Km7 exhibited maximum colony forming units (CFU)/mL and produced 0.35 g ethanol/g inulin at 24 h, while Km8 showed maximum CFU/mL and produced 0.02 g ethanol/g inulin at 96 h. At 24 h in inulin + glucose medium, Km7 produced 0.40 g ethanol/g (inulin + glucose) and Km8 produced 0.20 g ethanol/g (inulin + glucose) with maximum CFU/mL for Km8 at 72 h, 40 % of that for Km7 at 36 h. Extracellular inulinase activity at 6 h for both Km7 and Km8 was 3.7 International Units (IU)/mL.

Elemental profiling and geographical differentiation of Ethiopian coffee samples through inductively coupled plasma-optical emission spectroscopy (ICP-OES), ICP-mass spectrometry (ICP-MS) and direct mercury analyzer (DMA)

This study was aimed to establish the elemental profiling and provenance of coffee samples collected from eleven major coffee producing regions of Ethiopia. A total of 129 samples were analyzed for forty-five elements using inductively coupled plasma (ICP)-optical emission spectroscopy (OES), ICP-mass spectrometry (MS) and direct mercury analyzer (DMA). Among the macro elements, K showed the highest levels whereas Fe was found to have the lowest concentration values. In all the samples, Ca, K, Mg, P and S contents were statistically significant (p<0.05). Micro elements showed the concentrations order of: Mn>Cu>Sr>Zn>Rb>Ni>B. Contents of the trace elements were lower than the permissible standard values. Inter-regions differentiation by cluster analysis (CA), linear discriminant analysis (LDA) and principal component analysis (PCA) showed that micro and trace elements are the best chemical descriptors of the analyzed coffee samples.

Topical application of spent coffee ground extracts protects skin from ultraviolet B-induced photoaging in hairless mice

The aim of this study was to evaluate the protective effect of spent coffee ground (SCG) on ultraviolet (UV) B-induced photoaging in hairless mice. The oil fraction (OSCG) and ethanol extract (ESCG) of SCG were prepared from SCG. OSCG contained a much higher level of caffeine (547.32 ± 1.68 μg mg(-1)) when compared to the sum of its chlorogenic acid derivatives (∼119 μg mg(-1)), and pyrazines were the major aromatic compounds in OSCG. OSCG effectively inhibited the UVB-induced increase in intracellular reactive oxygen species in HaCaT cells. Topical application of OSCG or ESCG significantly reduced the UVB-induced wrinkle formation in mice dorsal skin. The combined application of OSCG and ESCG (OEH) led to a decrease in the wrinkle area by over 35% when compared with the UVB-treated control (UVBC). Epidermal thickness was also reduced by 40%. This result was connected to the significant reduction in transdermal water loss (27%) and erythema formation (48%) that result from UVB irradiation. Polarization-sensitive optical coherence tomography (PS-OCT) and antibody-based histological analyses showed that OSCG and ESCG effectively suppressed the UVB-induced decrease in collagen content. The level of type 1 collagen (COL1) in the OEH group was enhanced by around 40% compared with the UVB control group (UVBC). This was attributed to the down-regulation of matrix metalloproteinases (MMP2, 9, and 13), which are known to be responsible for collagen destruction. Our results indicate that topical treatment with OSCG/ESCG protects mouse skin from UVB-induced photoaging by down-regulating MMPs; therefore, suggesting the potential of SCG extracts as a topical anti-photoaging agent.

Effect of genuine non-anthocyanin phenolics and chlorogenic acid on color and stability of black carrot (Daucus carota ssp. sativus var. atrorubens Alef.) anthocyanins

This work aimed at studying the color intensity and stability of black carrot anthocyanins as influenced by intermolecular co-pigmentation. For this purpose, purified anthocyanin solutions were supplemented with purified genuine black carrot phenolics, chlorogenic acid, and an aqueous phenolic-rich green coffee bean extract at various anthocyanin:co-pigment ratios (1:0-1:162; pH 3.6). The hyperchromic co-pigmentation effect depended on the concentration of added co-pigments, resulting in an absorbance increase of up to 22% at the absorption maximum. Anthocyanin stability during heating (90°C, 5h) was barely improved unless the concentrations of co-pigments exceeded those of their natural source. When adding co-pigments at ratios above 1:9.4, anthocyanin heat stability was significantly improved. As acylated anthocyanins were most stable, breeders might aim at increasing their content in the future, while breeding for high levels of colorless polyphenols may be unreachable. Nevertheless, we provided proof-of-concept for the successful color enhancement by the addition of a phenolic-rich green coffee bean extract, being useful for food-grade applications.

Development of an instant coffee enriched with chlorogenic acids

The objective of this study was to present possible formulations for an instant coffee product enriched with chlorogenic acids for the Brazilian market. Formulations were prepared with different concentrations of freeze dried extracts of green Coffea canephora beans (G) added to freeze dried extracts of roasted Coffea arabica (A) and Coffea canephora (C). Medium (M) and dark (D) roasting degrees instant coffee were produced (AM, AD, CM and CD) to obtain four formulations with green extract addition (AMG, ADG, CMG and CDG). Chlorogenic acids were determined by HPLC, with average contents of 7.2 %. Roasted extracts and formulations were evaluated for 5-CQA and caffeine contents (by HPLC), browned compounds (absorbance 420 nm), and antioxidant activity (ABTS and Folin). Coffee brews of the four formulations were also assessed in a lab-scale test by 42 consumers for acceptance of the color, aroma, flavor and body, overall acceptance and purchase intent, using a 10 cm hybrid scale. The formulations obtained acceptance scores of 6.6 and 7.7 for all attributes, thus they were equally acceptable. Greater purchase intent was observed for ADG, CDG and CMG (6.9) in comparison to AMG (6.1). The formulations had, on average, 2.5 times more 5-CQA than the average obtained from conventional commercial instant coffees. In addition to being more economically viable, the formulations developed with C. canephora (CDG and CMG) showed greater antioxidant potential (32.5 g of Trolox/100 g and 13.8 g of gallic acid equivalent/100 g) due to a balance in the amount of bioactive compounds.