Coffea Arabica Beans Research Articles

Lactam ent-Kaurane Diterpene: A New Class of Diterpenoids Present in Roasted Beans of Coffea arabica.

Seven new lactam ent-kaurane diterpenoids, cafemides A-G (1-7), were isolated from roasted beans of Coffea arabica. Their structures were elucidated by extensive spectroscopic analysis including 1D, 2D NMR (heteronuclear single quantum correlation (HSQC), heteronuclear multiple bond correlation (HMBC), 1H-1H correlation spectroscopy (COSY), and rotating frame Overhauser effect spectroscopy (ROESY)), high-resolution electrospray ionization mass spectrometry (HRESIMS), and IR spectra. They were divided into subtype I-III according to the structure. Further, with the aid of liquid chromatography-tandem mass spectrometry (LC-MS/MS) based molecular network, seven (8-14) subtype II diterpenoids were successfully identified. In addition, a variety of other subtypes of N-containing diterpenoids have been proven in roasted coffee. Compounds 1, 2, 3, 5, and 7 showed a moderate inhibitory effect on α-glucosidase with an IC50 value of 8.28 ± 0.62 μM, 38.23 ± 8.87 μM, 28.94 ± 1.42 μM, 12.44 ± 1.37 μM, and 22.2 ± 5.34 μM, respectively. To the best of our knowledge, this is the first time that N-containing diterpenoids have been reported in coffee.

Factorial design fingerprint discrimination of Coffea arabica beans under elevated carbon dioxide and limited water conditions

Coffee is one of the most important commodities, showing sensitivity to environmental variations. The main effects and their interaction for two levels of atmospheric CO2 concentrations and two water regimes of a factorial design were investigated for the metabolic profiles of Coffea arabica raw beans using UV fingerprint analysis from a mixture design. UV fingerprint results obtained from pure ethanol and binary ethanol-dichloromethane mixtures showed the largest metabolic discriminations between CO2 levels and their extracts were investigated in detail. The biosynthesis of major metabolites, chlorogenic acids, cafestol, kahweol and caffeine were altered owing to environmental conditions. Higher amounts of chlorogenic acids and kahweol were observed in beans from unirrigated plants grown with enriched CO2 and irrigated ones at the current CO2 level. Water availability and CO2 concentration interaction affects the metabolite amounts. Besides a significant CO2 atmospheric effect water availability was a limiting factor for metabolite content only at current CO2 level, suggesting the successful metabolic coping of CO2 enriched Arabic coffee beans suffering future droughts.

Irrigated and CO2 level effects on metabolism in Coffea arabica beans from mixture design – near infrared fingerprints

Coffee bean metabolites are regulated in response to environmental factors, such as climate change and abiotic stress that could influence the quality of beverage. Therefore, the development of methodologies that can indicate chemical changes owing to these perturbations becomes important for making decisions about the coffee culture future. The present study proposes an exploratory analysis of metabolic changes of Coffea arabica beans by means of the spectral fingerprints acquired by Near Infrared Spectroscopy (NIR) combined with Principal Component Analysis (PCA). Coffee plants were cultivated in Free-Air Carbon dioxide Enrichment (FACE) experiment under two CO2 levels, current or elevated, supplied with irrigation or cultivated under rainfed conditions (unirrigated). When measurements were made directly on the raw coffee beans in reflectance mode, the results of the NIR spectra fingerprints did not discriminate the coffee beans originated from different cultivation conditions. An alternative methodology was proposed, using NIR spectral fingerprints in transmittance mode obtained from the statistical mixture design extract solutions. Among ethanol, dichloromethane, hexane, ethyl ether and their combinations, the PCA showed that pure ethanol and the mixture involving ethanol and dichloromethane (1:1 v/v) were the solvents permitting the coffee beans discrimination. A larger number of samples then confirmed the discrimination between the different CO2 levels and irrigation conditions for these extracts. Bands in different regions were responsible for these discriminations and were different for extracts of ethanol and the mixture ethanol and dichloromethane. Results indicate that labeling depends on the intrinsic properties of the organic matrix and the type of solvent used. Furthermore, in the impossibility of an exploratory analysis of the NIR spectra acquired directly on the raw coffee beans, the experimental design, to obtain extracts using different solvents, associated with the obtaining of the spectral fingerprints in the NIR region in transmittance mode, showed an alternative to this situation.

The influence of brewing method on bioactive compounds residues in spent coffee grounds of different roasting degree and geographical origin

SummaryThe content of bioactive compounds in spent coffee grounds (SGC) was studied. SGC were obtained from Coffea arabica beans of different roasting degrees (light and dark) and different geographical origins (Nicaragua, Columbia and Mexico) processed using four brewing methods (mocha, filtered, drip and infusion). The highest caffeine and chlorogenic acid contents were determined in filtered spent coffee extracts. All extracts of light roasted spent coffee grounds showed lower browning index levels in comparison to that from dark roasted spent coffee grounds. Generally, the highest content of total polyphenolic compounds and highest antioxidant capacity were determined in extracts prepared in drip. In conclusion, the results obtained in this study indicate that the spent coffee grounds produced of domestic levels, especially those obtained from filter coffeemaker, could be considered as a good source of natural antioxidants.

Quality and bioactive compounds of blends of Arabica and Robusta spray-dried coffee

The objective of this study was to develop both a possible process and a spray-dried coffee product with a balanced content of bioactive compounds. Spray-dried coffees were prepared by mixing different ratios of medium-roasted Coffea canephora (R) with green Coffea arabica (A) beans. Overall, quality characteristics of spray-dried coffees were not different. The dominant signals of 1D 1H NMR were identified as trigonelline, caffeine and chlorogenic and organic acids. Principal component analysis explained 81.8% of the total variance. Roasted Robusta spray-dried coffee was clearly distinguished from blended coffees. Forty-two volatile compounds were identified. An increase in green Arabica mixed with roasted Robusta in the blends resulted in an increase in 5-caffeoylquinic acid but a decrease in caffeine contents. Spray-dried coffee prepared from a A35:R65 showed greater total phenolic content and antioxidant activity due to a balance in bioactive compounds. In addition, its coffee brew obtained the highest overall liking score.

Spatial distributions of furan and 5-hydroxymethylfurfural in unroasted and roasted Coffea arabica beans

For the first time, the spatial distributions of the highly volatile compounds furan and 5-hydroxymethylfurfural (HMF) have been determined in cross sections of green and roasted Coffea arabica beans. The image maps were revealed by laser ablation DART imaging mass spectrometry (LADI-MS). The presence of these compounds was independently confirmed by GC–MS as well as argon DART-MS. Quantification of furan by GC–MS was completed with the final concentrations in roasted and unroasted beans determined to be 96.5 and 4.1 ng/g, respectively. Furan was observed to be distributed throughout the tissue of both green and roasted beans, while HMF was localized to the silver skin in green beans. Following roasting, the appearance of HMF was more diffuse. The implications of the broad distribution of furan on the one hand, and localization of HMF on the other, are discussed.

Kahweol inhibits proliferation and induces apoptosis by suppressing fatty acid synthase in HER2-overexpressing cancer cells

Kahweol is a coffee-specific diterpene found in the beans of Coffea arabica and has been reported to demonstrate various biological activities, including anti-inflammatory, antioxidant, and apoptotic properties. In the present study, we examined the molecular mechanism of kahweol in human epidermal growth factor receptor-2 (HER2)-overexpressing breast cancer cells. Kahweol preferentially inhibited cell proliferation and induced cell death through the induction of a caspase 3-dependent pathway in HER2-overexpression breast cancer cell lines. Kahweol treatment substantially reduced the levels of HER2 protein, mRNA, and transcriptional activity in SKBR3 cells. Kahweol exerts its potent anticancer efficacy by the upregulation of polyomavirus enhancer activator 3 (PEA3) and downregulation of activator protein 2 (AP-2) to inhibit aberrantly activated HER2 signaling. Fatty acid synthase (FASN) expression and sterol regulatory element-binding protein-1c (SREBP-1c) activity were downregulated by kahweol. In addition, kahweol lowered the levels of phosphorylated Akt and its downstream targets mammalian target of rapamycin (mTOR) and cyclin D1. Furthermore, we found that blocking Akt signaling through kahweol treatment significantly reduced FASN expression and subsequently suppressed cell proliferation in HER2-overexpressing cancer cells. Overall, this study suggests that kahweol could be a useful adjuvant therapeutic agent in the treatment of HER2-overexpressing breast cancer.

SNP in the Coffea arabica genome associated with coffee quality

Association analysis was performed at the whole genome level to identify loci affecting the caffeine and trigonelline content of Coffea arabica beans. DNA extracted from extreme phenotypes was bulked (high and low caffeine, and high and low trigonelline) based on biochemical analysis of the germplasm collection. Sequencing and mapping using the combined reference genomes of C. canephora and C. eugenioides (CC and CE) identified 1351 non-synonymous SNPs that distinguished the low- and high-caffeine bulks. Gene annotation analysis with Blast2GO revealed that these SNPs corresponding to 908 genes with 56 unique KEGG pathways and 49 unique enzymes. Based on KEGG pathway-based analysis, 40 caffeine-associated SNPs were discovered, among which nine SNPs were tightly associated with genes encoding enzymes involved in the conversion of substrates (i.e. SAM, xanthine and IMP) which participate in the caffeine biosynthesic pathways. Likewise, 1060 non-synonymous SNPs were found to distinguish the low- and high-trigonelline bulks. They were associated with 719 genes involved in 61 unique KEGG pathways and 51 unique enzymes. The KEGG pathway-based analysis revealed 24 trigonelline-associated SNPs tightly linked to genes encoding enzymes involved in the conversion of substrates (i.e. SAM, L-tryptophan) which participate in the trigonelline biosynthesis pathways. These SNPs could be useful targets for further functional validation and subsequent application in arabica quality breeding.

HPTLC Profiles and Antioxidant Activities from Leaves to Green and Roasted Beans of Coffea Arabica

The health benefits of coffee consumption are a very actual research subject, given the fact that is one of the most popular beverages in the world. The majority of the studies are concentrated to coffee beans (green or roasted) chemical composition (the most important non-volatile compounds investigated being phenols and alkaloids) and pharmacological activity. Green coffee is now in the market in the form of food supplements products. In the present, the chemical composition and bioactivity of the leaves occupy a small place in scientific papers.
 This research paper investigate, in terms of caffeine, phenolic compounds composition and antioxidant activities, the differences and similarities between hydroalcoholic extracts of Coffea arabica leaves and green and roasted beans. The extracts profiles, determined by HPTLC technique, shows the major phenolic compounds. Through chromatographic fingerprint, the presence and the amount of caffeine in the extracts were also determined. The total phenolic content (TPC) (Folin Ciocalteu method) expressed as gallic acid equivalents decrease from the leaves to green and roasted coffee beans extracts. The IC50 (concentration of sample required to inhibit 50% of the DPPH free radical) was determined by free radical scavenging activity of Dpph. The IC50 values were TPC concentration-dependent. The obtained results show that in the hydroalcoholic extracts of the leaves are almost the same major phenolic compounds as in the green coffee beans extract. Also, the leaves extract have a higher content in total phenols and a better antioxidant activity comparative to the other samples. Therefore, this paper can be the first step for further investigations of coffee leaves extracts, which might have important health beneficial effects and can be a reliable raw material for food supplements industry.

Identification of new diterpene esters from green Arabica coffee beans, and their platelet aggregation accelerating activities

Eight new ent-kaurane diterpene fatty acid esters, namely caffarolides A–H (1–8), were isolated from green beans of Coffea arabica. Their chemical structures were confirmed by extensive spectroscopic analysis including 1D, 2D NMR (HSQC, HMBC, 1H–1H COSY, and ROESY), HRMS, IR and CD spectra and by GC-FID analysis. Interestingly, the diterpene moiety of these new compounds first occurred in genus Coffea. All the isolates were evaluated for platelet aggregation activity in vitro. As the results, caffarolides C, D and F (3, 4 and 6) showed induction effect for platelet aggregation and the possible structure-activity relationships have been discussed briefly.

Potential effect of compounds isolated from Coffea arabica against UV-B induced skin damage by protecting fibroblast cells

Ultraviolet (UV) radiation has adverse effects on extracellular matrix (ECM) proteins, leading to formation of wrinkles a hallmark of premature skin aging. The adverse effects of UV radiation are associated with induction of matrix metalloproteinases (MMPs) expression and degradation of collagen and elastin. The present study investigated anti-wrinkle effects of chlorogenic acid (CGA), pyrocatechol (PC) and 3,4,5-tricaffeoyl quinic acid (TCQ), isolated from beans of Coffea arabica, against UV-B stimulated mouse fibroblast cells (CCRF) by measuring expression levels of MMP-1, 3, 9, and type-I procollagen. The three compounds were isolated and purified from coffee grounds using column chromatography and structural examination was evaluated by nuclear magnetic resonance (NMR) analysis. Among the three isolated compounds, CGA effectively suppressed the expression of the MMP-1, 3, and 9 and increased synthesis of type-I procollagen as compared UV-B-stimulated CCRF cells. In addition, CGA dose-dependently inhibited intracellular reactive oxygen species (ROS) production in CCRF cells stimulated by UV radiation. Moreover, CGA displayed a good sun protection factor (SPF) and in vitro DNA damage protection together with inhibition of enzyme xanthine oxidase. The enzyme inhibitory kinetic behavior of CGA was determined by Lineweaver-Burk plot, displayed a mixed type enzyme inhibition with 260.3±4.5μM, Ki value. The results indicate that CGA has potential to be used as a preventive agent against premature skin aging induced by UV radiation.

Kahweol decreases hepatic fibrosis by inhibiting the expression of connective tissue growth factor via the transforming growth factor-beta signaling pathway.

Kahweol is a diterpene molecule found in Coffea Arabica beans. Previous studies have shown that coffee reduces liver fibrosis, but it is not clear which component of coffee has the protective effect. In this study, we examined whether kahweol has a protective effect on hepatic fibrosis in vivo and in vitro. Kahweol decreased hepatic fibrosis by inhibiting connective tissue growth factor (CTGF) expression in thioacetamide (TAA)-treated mice. The expression of phospho-Smad3, signal transducer and activator of transcription 3 (STAT3), extracellular signal-regulated kinases (ERK), and c-Jun N-terminal protein kinase (JNK) increased in the livers of TAA-treated mice and decreased in the kahweol-treated group. Kahweol significantly decreased the expression of transforming growth factor beta (TGF-β)-stimulated type I collagen and CTGF expression in vitro. In addition, kahweol significantly decreased the expression of Smad3, STAT3, ERK and JNK, which are involved in the induction of CTGF expression by TGF-β in hepatocytes, but not in HSCs. These results suggest that kahweol may be a new candidate for treatment of liver fibrosis.

Rapid Prediction of Moisture Content in Intact Green Coffee Beans Using Near Infrared Spectroscopy.

Moisture content (MC) is one of the most important quality parameters of green coffee beans. Therefore, its fast and reliable measurement is necessary. This study evaluated the feasibility of near infrared (NIR) spectroscopy and chemometrics for rapid and non-destructive prediction of MC in intact green coffee beans of both Coffea arabica (Arabica) and Coffea canephora (Robusta) species. Diffuse reflectance (log 1/R) spectra of intact beans were acquired using a bench top Fourier transform NIR instrument. MC was determined gravimetrically according to The International Organization for Standardization (ISO) 6673. Samples were split into subsets for calibration (n = 64) and independent validation (n = 44). A three-component partial least squares regression (PLSR) model using raw NIR spectra yielded a root mean square error of prediction (RMSEP) of 0.80% MC; a four component PLSR model using scatter corrected spectra yielded a RMSEP of 0.57% MC. A simplified PLS model using seven selected wavelengths (1155, 1212, 1340, 1409, 1724, 1908, and 2249 nm) yielded a similar accuracy (RMSEP: 0.77% MC) which opens the possibility of creating cheaper NIR instruments. In conclusion, NIR diffuse reflectance spectroscopy appears to be suitable for rapid and reliable MC prediction in intact green coffee; no separate model for Arabica and Robusta species is needed.

Chemical partitioning and antioxidant capacity of green coffee (Coffea arabica and Coffea canephora) of different geographical origin

Green coffee beans of Coffea arabica and Coffea canephora accessions from different geographical origin (Brazil, Colombia, Ethiopia, Honduras, Kenya, Mexico, Peru, Uganda and Vietnam) were extracted and the extracts analyzed by HPLC–ESI-MS/MS for the identification and quantification of chlorogenic acids and caffeine content. Principal component and cluster analyses were used to identify chemical patterns separating the different species and accessions based on their geographical origin. C. canephora showed always a higher caffeine content with respect to C. arabica, whereas the C. arabica accessions from Kenya showed a higher chlorogenic acids and a lower caffeine content. The antioxidant capacity of green coffee extracts was assayed by the reducing power and DPPH assays. The antioxidant capacity correlated with the chlorogenic acids content. The results show that the C. arabica from Kenya possesses the highest chlorogenic acids/caffeine ratio and, among the C. arabica accessions, the highest antioxidant capacity. Therefore, the C. arabica from Kenya is the most suitable green coffee source for nutraceutical applications because of its high antioxidant capacity and low caffeine content.

Stable radical content and anti-radical activity of roasted Arabica coffee: from in-tact bean to coffee brew.

The roasting of coffee beans generates stable radicals within melanoidins produced by non-enzymatic browning. Roasting coffee beans has further been suggested to increase the antioxidant (AO) capacity of coffee brews. Herein, we have characterized the radical content and AO capacity of brews prepared from Coffea arabica beans sourced directly from an industrial roasting plant. In-tact beans exhibited electron paramagnetic resonance signals arising from Fe3+, Mn2+ and at least three distinct stable radicals as a function of roasting time, whose intensity changed upon grinding and ageing. In coffee brews, the roasting-induced radicals were harboured within the high molecular weight (> 3 kD) melanoidin-containing fraction at a concentration of 15 nM and was associated with aromatic groups within the melanoidins. The low molecular weight (< 3 kD) fraction exhibited the highest AO capacity using DPPH as an oxidant. The AO activity was not mediated by the stable radicals or by metal complexes within the brew. While other non-AO functions of the roasting-induced radical and metal complexes may be possible in vivo, we confirm that the in vitro antiradical activity of brewed coffee is dominated by low molecular weight phenolic compounds.

Effect of vacuum roasting on acrylamide formation and reduction in coffee beans

Coffea arabica beans were roasted in an oven at 200°C for increasing lengths of time under vacuum (i.e. 0.15kPa). The samples were then analysed for colour, weight loss, acrylamide concentration and sensory properties. Data were compared with those obtained from coffee roasted at atmospheric pressure (i.e. conventional roasting), as well as at atmospheric pressure for 10min followed by vacuum treatment (0.15kPa; i.e. conventional-vacuum roasting). To compare the different treatments, weight loss, colour and acrylamide changes were expressed as a function of the thermal effect received by the coffee beans during the different roasting processes. Vacuum-processed coffee with medium roast degree had approximately 50% less acrylamide than its conventionally roasted counterpart. It was inferred that the low pressure generated inside the oven during the vacuum process exerted a stripping effect preventing acrylamide from being accumulated. Vacuum-processed coffee showed similar colour and sensory properties to conventionally roasted coffee.

High-Throughput Metabolic Profiling of Diverse Green Coffea arabica Beans Identified Tryptophan as a Universal Discrimination Factor for Immature Beans

The maturity of green coffee beans is the most influential determinant of the quality and flavor of the resultant coffee beverage. However, the chemical compounds that can be used to discriminate the maturity of the beans remain uncharacterized. We herein analyzed four distinct stages of maturity (immature, semi-mature, mature and overripe) of nine different varieties of green Coffea arabica beans hand-harvested from a single experimental field in Hawaii. After developing a high-throughput experimental system for sample preparation and liquid chromatography-mass spectrometry (LC-MS) measurement, we applied metabolic profiling, integrated with chemometric techniques, to explore the relationship between the metabolome and maturity of the sample in a non-biased way. For the multivariate statistical analyses, a partial least square (PLS) regression model was successfully created, which allowed us to accurately predict the maturity of the beans based on the metabolomic information. As a result, tryptophan was identified to be the best contributor to the regression model; the relative MS intensity of tryptophan was higher in immature beans than in those after the semi-mature stages in all arabica varieties investigated, demonstrating a universal discrimination factor for diverse arabica beans. Therefore, typtophan, either alone or together with other metabolites, may be utilized for traders as an assessment standard when purchasing qualified trading green arabica bean products. Furthermore, our results suggest that the tryptophan metabolism may be tightly linked to the development of coffee cherries and/or beans.

Geographic determination of coffee beans using multi-element analysis and isotope ratios of boron and strontium

This study aims to evaluate the feasibility of using chemical and isotopic compositions of coffee beans to identify their geographic origins. Twenty-one Coffea arabica beans collected from 14 countries in 3 major coffee-producing regions, Africa, America and Asia, were analysed for multi-element of B, Rb, Sr, Ba, Fe, Mn and Zn, as well as isotopic compositions of B and Sr. Our results demonstrate that the geographic origin of coffee beans could be classified based on concentrations of Rb, Sr and Ba. However, the isotope ratios of B and Sr provide more sensitive information for the growth localities. Combined with literature data, this study indicates that B and Sr isotopes are excellent indicators of the origin of coffee beans.

Molecular heterogeneity of arabinogalactan-protein from Coffea arabica instant coffee

Arabinogalactan-protein complex (AGP), isolated from freeze-dried instant coffee powder of Coffea arabica beans, was subjected to ion-exchange chromatography. Stepwise elution with water and solutions of sodium chloride with increasing ionic strength afforded eight fractions (F1–F8). Chemical analyses have shown that compositions of individual conjugates varied in carbohydrate and protein contents, molecular mass and slightly in monosaccharide composition. Protein content was increasing by increasing ionic strength of the eluent and it was confirmed also by FT-IR spectra. NMR study has shown that carbohydrate moieties in individual ion exchange fractions differed in the degree of backbone and side chains branching. Performed study has confirmed a molecular heterogeneity of arabinogalactan-protein complex present in a commercial instant coffee.

Quality assessment of Arabica and Robusta green and roasted coffees ? A rev

This review is a synopsis on coffee quality assessment of green and roasted coffee beans of Coffea arabica and Coffea canephora. The particle size, medium sieve, most frequent sieve, share split, cumulative calibration, trade homogeneity, mass of 1000 beans, apparent density, strange bodies and defects, mass losses on drying, olfactory and visual parameters, chromatic parameters, soluble solids, pH and chemical characterization (chlorogenic acids, caffeine and trigonelline) is described and evaluated, considering the most important factor associated to the coffee trade, according to a technological perspective.