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It is commonly assumed that coffee particles swell during filtration, but it has not been clarified how different degrees of swelling affect the extraction. In this article, we propose a grain swelling model to investigate the influences of swelling on both intra-grain and inter-grain transport. The swelling is modeled through a diffusion process of excess water into the grains. The geometric expansion of the grains is connected to the local concentration of excess water through a specified deformation gradient tensor. Diffusion of soluble compounds inside the grains is coupled with the swelling dynamics through a modified diffusion equation. Inter-grain transport is modeled by solving the Navier–Stokes equation and diffusion equations. This model is solved numerically in the framework of smoothed particle hydrodynamics, and it is used to simulate the extraction of a minimal coffee bed setup and to investigate the effect of a small degree of particle swelling (< 8 % in size) on the extraction kinetics. It is found that under the normal operating parameter regime of espresso filtration, swelling affects the extraction mainly through the change of inter-grain transport. Swelling also alters the diffusion inside the grains, but this process has a secondary effect on the extraction. In general, swelling slightly impedes the extraction rate, but enhances the strength considerably at both fixed brewing time and fixed brewing volume. Our results justify the endeavor in the literatures to clarify the effect of possible swelling on brewing and preparation variables during coffee extraction. [ABSTRACT FROM AUTHOR]

Swelling of coffee particle is difficult to measure and control, but it could have significant effects on espresso extraction. In this article, we incorporate a particle-level swelling model to a one dimensional bed-level extraction model to investigate the effects of swelling on extraction. Realistic geometric parameters and brewing parameters are used. A small degree of swelling is assumed to be present (≈ 3. 6 % in size). Our simulation results show that swelling only slightly affects the yield and the strength if the flow rate is fixed. However, when the pressure drop is fixed swelling will considerably enhance the strength at both fixed brewing time and fixed brewing mass. The finer the coffee particles the more pronounced the enhancement. By tuning the partition coefficient, the one-dimensional extraction model is shown to be able to capture very well the extraction kinetics of a fixing-flow-rate espresso machine in low beverage mass regime ( M c < 30 g). Our results suggest that better yield and strength control can be achieved by fixing the flow rate in an espresso machine. Moreover, it is indicated that when properly incorporated with relevant physical effects, numerical extraction simulations can be used to predict the extraction kinetics of espresso machine and guide their design and production. • A swelling model is incorporated into a 1-D coarse-grained extraction model. • Effects of particle swelling is minimized if the flow rate is fixed. • Strength is considerably enhanced by swelling if the pressure drop is fixed. • Fixing flow rate helps minimize extraction variability. [ABSTRACT FROM AUTHOR]

Lignans are a class of polyphenols considered to be phytoestrogens because of their oestrogenic/antiestrogenic activities and their plant origin. Few works have reported on the content of lignans in ground coffee, and most of them analysed a small number of samples. Hence, our aim was to quantify the content of three lignans, secoisolariciresinol, lariciresinol and matairesinol, in ground coffee by using high-performance liquid chromatography tandem mass spectrometry. Evaluation of acidic hydrolysis, methanolic extractions, and enzymatic digestions as extraction methods indicated that enzymatic digestion with Taka-diastase 2% was the best. When this method was applied to 30 different ground coffees, we found that SECO was the highest concentration lignan (84.4-257.8 μg kg-1), followed by LARI (26.1-91.5 μg kg-1). Moreover, comparison of lignan extraction yield in espresso coffee and ground coffee showed that these molecules seem to be completely extracted during espresso coffee percolation, since the extraction yield average was 95.2%. [ABSTRACT FROM AUTHOR]

Abstract: 3‐Alkyl‐2‐methoxypyrazines (MPs) are a very important class of volatile organic compounds (VOCs), intensively characterizing the aroma of several food products including fruits and vegetables. Due to the very low orthonasal sensory threshold, low amounts of MPs may act as key positive or negative aroma compounds. The analysis of these volatiles in foods is then remarkably important, and it may be very challenging as confirmed by the scarce literature focused on MPs, particularly with respect to quantitative data. In the attempt to fill this gap, in this work, presence and quantification of MPs in four different vegetables, namely, green bell pepper (Capsicum annuum L. var grossum), green pea (Pisum sativum L. and Pisum spp), carrot (Daucus carota subsp sativus), and cucumber (Cucumis sativus L.) have been investigated. Two different volatile extraction techniques (solid phase microextraction [SPME] and simultaneous distillation‐extraction [SDE]) in conjunction with VOC qualitative analysis by gas chromatography‐mass spectrometry (GC‐MS) methods were applied. Solid phase microextraction coupled with GC‐MS in single ion monitoring (SIM) mode showed the best performances in sensitivity to detect MPs on the different vegetable matrices. Therefore, a headspace (HS) SPME‐GC‐MS quantitative method was developed and optimized, and dominant MPs quantified. 3‐Isopropyl‐2‐methoxypyrazine (IPMP), 3‐sec‐butyl‐2‐methoxypyrazine (sBMP), and 3‐isobutyl‐2‐methoxypyrazine (IBMP) have been detected and quantified in all the vegetables. 3‐Isopropyl‐2‐methoxypyrazine was the prevalent MP in peas and cucumber while IBMP in bell pepper. These MPs were detected for the first time in carrot and cucumber. Finally, sBMP has been confirmed to be the most important MP in carrot. The developed method allowed to characterize the VOC pattern and, in particular, to quantify MPs in four vegetables. Results highlight the feasibility of further applications of the analytical approach to determine MPs in other food matrices where an excessive amount of these aromas may negatively affect their flavor (eg, coffee). [ABSTRACT FROM AUTHOR]

Abstract: Lignans are polyphenolic compounds that are considered phytoestrogens for their plant origins, and they possess different biological activities. Three different extraction methods, ie, “dilute and shoot”, acidic hydrolysis, and enzymatic digestion, have been compared for extracting lignans (secoisolariciresinol (SECO), matairesinol (MAT), and lariciresinol (LARI)) from espresso coffee (EC) by using high‐performance liquid chromatography (HPLC) tandem mass spectrometry (MS/MS). The best recovery values (SECO: 97%, LARI: 98%, and MAT: 93%) were obtained by using enzymatic hydrolysis with Clara‐Diastase at 10% (w/v), keeping the sample at 37°C for 3 hours. For this reason, this method has been chosen and then applied to quantify lignans in 9 different EC samples from 5 different geographical origins (Brazil, Colombia, El Salvador, Ethiopia, and India). Secoisolariciresinol and LARI were found in all EC samples from 27.9 to 52.0 μg L−1 and from 5.3 to 27.8 μg L−1 respectively, contrary to MAT that it was not possible to detect it in each type of coffee. This method confirms the high specificity and sensitivity of MS/MS system for detecting bioactives in complex matrix such as coffee. [ABSTRACT FROM AUTHOR]

• Leaf LDs are generally less known and studied than seed LDs, in spite of playing an important role in plant defense against abiotic stress or pathogen attack and other important metabolic pathways. • LDs are detected for the first time in leaves of different coffee species, with different size and distribution. • LDs presence depends on both coffee species and seasonal period. The present investigation aims to ascertain the presence of cytoplasmic lipid droplets (LDs) in different Coffea sp. leaf tissues. A detailed morpho-anatomical characterization, in addition to highlighting that the overall internal leaf tissue organization is independent of the coffee botanical species, put in evidence for the first time the presence of LDs in Coffea sp. leaves. Leaves from plant accessions of several coffee species, kept under greenhouse conditions, have been sampled in two different periods (January and June). Cytoplasmic LDs have been observed in all samples and they are mainly present as a single body, ranging from a minimum diameter of 1 µm to a maximum of 10 µm, detected in both palisade and spongy parenchyma cells of mesophyll tissue. In some case LDs are also sporadically observed in some epidermal cells in both abaxial or adaxial surface or in the subsidiary cells of stomata. Depending on season as well as coffee species, LDs show variability in terms of quantity, size, clustering and tissue distribution (presence in the mesophyll and/or epidermal tissue). The occurrence of LDs in a particular coffee leaf tissue is the prerequisite to further explore the physiological role of these organelles and reveal their possible functional benefits. [ABSTRACT FROM AUTHOR]

A new method for extracting isoflavones from espresso coffee (EC) was coupled with high-performance liquid chromatography- tandemmass spectrometry (MS/MS) for the first time to analyse five isoflavones, which included both a glycosilated form, genistin and the aglycons daidzein, genistein, formononetin and biochanin A. Isoflavones were extracted fromcoffee samples usingmethanol, stored in a freezer overnight to precipitate proteic or lipidic residues and purified on SPE C18 cartridges before highperformance liquid chromatography-MS/MS analysis. The recovery percentages obtained by spiking the matrix at concentrations of 10 and 100 μg l-1 with a standard mixture of isoflavones were in the range of 70 to 104%. The limits of detection and limits of quantification were in the range of 0.015-0.3 μg l-1 and 0.05-1 μg l-1, respectively. Once validated, the method was used to analyze the concentrations of isoflavones in six ECs and ten ground coffee samples. Only formononetin and biochanin A were found, and their respective concentrations ranged from 0.36 to 0.41 μg l-1 and from 0.58 to 3.26 μg l-1 in ECs and from 0.36 to 4.27 μgkg-1 and from 0.71 to 3.95 μgkg-1 in ground coffees. This method confirms the high specificity and selectivity of MS/MS systems for detecting bioactives in complex matrices such as coffee. [ABSTRACT FROM AUTHOR]

This study applies proton transfer reaction time-of-flightmass spectrometry for the rapid analysis of volatile compounds released from single coffee beans. The headspace volatile profiles of single coffee beans (Coffeea arabica) from different geographical origins (Brazil, Guatemala and Ethiopia) were analyzed via offline profiling at different stages of roasting. The effect of coffee geographical origin was reflected on volatile compound formation that was supported by one-way ANOVA. Clear origin signatures were observed in the formation of different coffee odorants. [ABSTRACT FROM AUTHOR]

Coffee extraction involves many complex physical and transport processes extremely difficult to model. Among the many factors that will affect the final quality of coffee, the microstructure of the coffee matrix is one of the most critical ones. In this article, we use X-ray micro-computed (microCT) technique to capture the microscopic details of coffee matrices at particle-level and perform fluid dynamics simulation based on the smoothed particle hydrodynamics method (SPH) with the 3D reconstructured data. Information like flow permeability and tortuosity of the matrices can be therefore obtained from our simulation. We found that inertial effects can be quite significant at the normal pressure gradient conditions typical for espresso brewing, and can provide an explanation for the inconsistency of permeability measurements seen in the literature. Several types of coffee powder are further examined, revealing their distinct microscopic details and resulting flow features. By comparing the microCT images of pre- and post-extraction coffee matrices, it is found that a decreasing porosity profile (from the bottom-outlet to the top-inlet) always develops after extraction. This counterintuitive phenomenon can be explained using a pressure-dependent erosion model proposed in our prior work. Our results reveal not only some important hydrodynamic mechanisms of coffee extraction, but also show that microCT scan can provide useful microscopic details for coffee extraction modelling. MicroCT scan establishes the basis for a data-driven numerical framework to explore the link between coffee powder microstructure and extraction dynamics, which is the prerequisite to study the time evolution of both volatile and non-volatile organic compounds and then the flavour profile of coffee brews. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Abstract: The efficient synthesis of 3-, 4-, and 5-O-feruloylquinic acids starting from d-(−)-quinic acid is described. Esterification of suitably protected quinic acid derivatives with 3-(4-acetoxy-3-methoxyphenyl)-acryloyl chloride and subsequent hydrolysis of all the protecting groups afforded the title products in overall yields of 33%, 15%, and 45%, respectively, (from quinic acid). [Copyright &y& Elsevier]

Abstract: The coffee brewing technique enhances several surface phenomena such as foam and emulsion formation and stabilisation. Recently the authors have been investigated the possibility to study the different contribution of the components of commercially available coffees well known as arabica and robusta. In the present work, dynamic experimental techniques such as maximum bubble pressure and contact angle have been used to characterise the air- coffee beverage interface at two different temperatures (20°C and 37°C). Different coffee-based beverage have been investigated ranging from espresso to soluble coffee. Beverage samples at different brewing times and methods have been prepared following standard procedures by using commercially relevant varieties and products. The role of the chemical components on tensiometric behaviour of the beverage is discussed. This behaviour is definitely related to the good wetting properties of the beverage on oral mucosa. [Copyright &y& Elsevier]

Espresso coffee world-wide success, besides being a phenomenon of fashion, seems to be based on the greater sensory satisfaction it gives to the consumer when compared with coffees prepared with other brewing methods. Conditions normally used in the espresso brewing technique enhance several surface tension-related phenomena such as foam and emulsion formation and stabilisation which strongly affects the organoleptic beverage properties. In spite of the relevant role played by surface tension in several quality characteristics of espresso coffee, little attention has been paid in its determination and its time-dependency has not yet been investigated.In the present work, experimental techniques such as maximum bubble pressure and pendant drop have been used to characterise in a wide time window the dynamic surface tension of air–espresso coffee beverage interface at two different temperatures. The experimental data show a remarkable decrease of the surface tension with time for beverages prepared by using pure arabica as well as pure robusta roasted coffee, with a profile dependent upon the coffee variety. This behaviour is definitely related to the presence of surface active components and is consistent with a system having good wetting properties for oral cavity surfaces. A possible role of some natural surface active chemical components, like lipids, on tensiometric behaviour is discussed. [Copyright &y& Elsevier]

Coffee is one of the most enjoyed beverages worldwide and whilst a wide array of secondary metabolites has been qualitatively and quantitatively characterised within the coffee bean, little is known about their distribution in different bean tissues. In this work, complementary mass spectrometry (MS) based approaches were utilised to determine the spatial metabolomic content of coffee beans, focusing on highlighting those which presented a regiospecific distribution and distinguished the different endosperm regions and the embryo. Preliminary exploration of the spatial metabolome of Coffea arabica coffee beans highlighted tissue-specific molecular features through an unsupervised statistical analysis. Then, the complementary information derived from higher resolution MS approaches resulted in the annotation of 13 metabolites which showed a specific enrichment in at least one tissue, and most of these were noted to be bioactive compounds or aroma/flavour precursors. Knowledge of the tissue distribution of these compounds could shed light on their biological role in plant physiology and bean development, but could also have relevant implications for their positive impact on human health due to coffee consumption as well as their possible effect on aroma and flavour upon roasting of green coffee beans. [ABSTRACT FROM AUTHOR]

• A new analytical method for lignan and isoflavone quantitation has been developed. • Base hydrolysis followed by enzymatic digestion was the best extraction process. • Lignans occurred in higher concentrations than isoflavones. • Matairesinol was not present in any samples. • Ethiopian green coffees may be a good source of lignans. Green coffee, the raw material of roasted coffee and coffee beverages, is one of the most widely traded commodities worldwide. There is a dearth of studies on its content in phytoestrogens such as isoflavones and lignans. Previously, we developed an efficient method for the simultaneous quantification of 6 isoflavones (daidzin, genistin, daidzein, genistein, formononetin and biochanin A) and 3 lignans (secoisolariciresinol, matairesinol and lariciresinol) in green coffee by using HPLC-MS/MS. Several extraction processes were evaluated and the best performing, base hydrolysis followed by enzymatic digestion, was validated and used to analyse 25 different coffee samples, 1 Coffea canephora and 24 Coffea arabica , from different countries. Lignans (total content: 286.5–8131.8 µg kg−1) were found in higher concentration than isoflavones (total content: 3.4–300.0 µg kg−1) and the most abundant were secoisolariciresinol (172.6–5714.1 µg kg−1) and lariciresinol (113.9–2417.7 µg kg−1). Notably, the Ethiopian coffee samples contained the highest levels of these compounds. [ABSTRACT FROM AUTHOR]

The synthesis of five hydroxycinnamoyl amides (HCAs) was accomplished and their identification and quantification in the green coffee bean samples of Coffeaarabica, Coffeacanephora, and Coffealiberica was performed. The HCAs p-coumaroyl-N-tyrosine 1b, caffeoyl-N-phenylalanine 2b, caffeoyl-N-tyrosine 3b, and p-coumaroyl-N-tryptophan 4b were characteristic of the C. canephora species while caffeoyl-N-tryptophan 5b was present in both C. canephora and C. arabica, but with higher content in C. canephora. The HCAs presence was also analyzed in C. liberica for the first time and none of the targeted compounds was found, indicating that this species is very similar to C. arabica species. Between C. canephora samples from various origins, significant differences were observed regarding the presence of all the HCAs, with C. canephora from Tanzania containing all five derivatives. [ABSTRACT FROM AUTHOR]

The main coffee diterpenes cafestol, kahweol, and 16-O-methylcafestol, present in the bean lipid fraction, are mostly esterified with fatty acids. They are believed to induce dyslipidaemia and hypercholesterolemia when taken with certain types of coffee brews. The study of their binding to serum albumins could help explain their interactions with biologically active xenobiotics. We investigated the interactions occurring between cafestol and 16-O-methylcafestol palmitates with Bovine Serum Albumin (BSA), Human Serum Albumin (HSA), and Fatty Free Human Serum Albumin (ffHSA) by means of circular dichroism and fluorimetry. Circular Dichroism (CD) revealed a slight change (up to 3%) in the secondary structure of fatty-free human albumin in the presence of the diterpene esters, suggesting that the aliphatic chain of the palmitate partly occupies one of the fatty acid sites of the protein. A warfarin displacement experiment was performed to identify the binding site, which is probably close but not coincident with Sudlow site I, as the affinity for warfarin is enhanced. Fluorescence quenching titrations revealed a complex behaviour, with Stern–Volmer constants in the order of 103–104 Lmol−1. A model of the HSA-warfarin-cafestol palmitate complex was obtained by docking, and the most favourable solution was found with the terpene palmitate chain inside the FA4 fatty acid site and the cafestol moiety fronting warfarin at the interface with site I. [ABSTRACT FROM AUTHOR]

The diterpene cafestol represents the most potent cholesterol-elevating compound known in the human diet, being responsible for more than 80% of the effect of coffee on serum lipids, with a mechanism still not fully clarified. In the present study, the interaction of cafestol and 16-O-methylcafestol with the stabilized ligand-binding domain (LBD) of the Farnesoid X Receptor was evaluated by fluorescence and circular dichroism. Fluorescence quenching was observed with both cafestol and 16-O-methylcafestol due to an interaction occurring in the close environment of the tryptophan W454 residue of the protein, as confirmed by docking and molecular dynamics. A conformational change of the protein was also observed by circular dichroism, particularly for cafestol. These results provide evidence at the molecular level of the interactions of FXR with the coffee diterpenes, confirming that cafestol can act as an agonist of FXR, causing an enhancement of the cholesterol level in blood serum. [ABSTRACT FROM AUTHOR]

The espresso extraction process involves a complex transport inside a geometry-changing porous medium. Large solid grains forming the majority of the porous medium can migrate, swell, and consolidate, and they can also morphologically change during flow, i.e., being mechanically eroded by hydrodynamic forces. These processes can, in turn, have a significant back-effect on the flow and the related coffee extraction profiles. In this article, we devise a bottom–up erosion model in the framework of smoothed dissipative particle dynamics to consider flow-induced morphological changes of the coffee grains. We assume that the coffee grains are not completely wetted and remain brittle. We found that heterogeneity in both the filtration direction and the transverse direction can be induced. The former is controlled by the angle of internal friction while the latter is controlled by both the cohesion parameter and the angle of internal friction. Not restricted to the modeling of espresso extraction, our model can also be applied to other eroding porous media. Our results suggest that, under ideal porous flow conditions, we can control the heterogeneity (in both the pressure drop direction and the transverse direction) of an eroding medium by tuning the yield characteristics of the eroding material. [ABSTRACT FROM AUTHOR]

Spent coffee ground (SCG) is the remaining residue produced after extraction of coffee, and it is considered a source of unextracted bioactive compounds. For this, in the latest years, the attention has been focused to innovative reuses that can exploit the potentiality of SCG. Unfortunately, the content of bioactive compounds has not been thoroughly studied yet, and the major of publication has investigated the caffeine and chlorogenic acids levels, total polyphenol contents, and total flavonoid content. Hence, these approaches have determined only an estimation of flavonoids and polyphenols content and lack on single polyphenols investigation. Therefore, the objective of the current work was to provide a deep characterization of bioactive compounds in SCG. For this purpose, a new analytical method for the quantification of 30 molecules, including caffeine, chlorogenic acids, phenolic acids, flavonoids, and secoiridoids, has been developed using high‐performance liquid chromatography tandem mass spectrometry. Moreover, several extraction procedures, that is, liquid–solid extraction assisted and not by ultrasounds, testing diverse solvents, were evaluated. Liquid–solid extraction assisted by sonication, with water/ethanol (30/70, v/v), resulted the best in terms of total bioactive compounds, and, once validated, the new analytical method was applied to five different espresso SCG samples. Data showed that caffeine (means: 1193.886 ± 57.307 mg kg−1) and chlorogenic acids (means of total CQAs: 1705.656 ± 88.694 mg kg−1) were the most abundant compounds in all SCG samples followed by phenolic acids such as caffeic, ferulic, gallic, p‐coumaric, syringic, trans‐cinnamic, and vanillic acid. Moreover, some flavonoids, that is, rutin, cyanidin 3‐glucoside, and quercetin, occurred in almost all samples. This work provided a deepened characterization of bioactive compounds in SCG and can contribute to develop new strategies of reuses. [ABSTRACT FROM AUTHOR]

The present study aims to both identify and quantify trans‐sinapoylquinic acid (SiQA) regioisomers in green coffee by combined UHPLC‐ESI‐QqTOF‐MS/MS and UHPLC‐ESI‐QqQ‐MS/MS methods. Among the various mono‐acyl chlorogenic acids found in green coffee, SiQA regioisomers are the least studied despite having been indicated as unique phytochemical markers of Coffea canephora (known as Robusta). The lack of commercially available authentic standards has been bypassed by resorting to the advantages offered by high‐resolution LC–MS as far as the identification is concerned. SiQA regioisomers have been identified in several samples of Robusta and Coffea arabica (known as Arabica) commercial lots from different geographical origin and, for the first time, in different samples of coffee wild species (Coffea liberica and Coffea pseudozanguebariae). Quantification (total SiQA ranging from 3 to 5 mg/100 g) let to reconsider these chlorogenic acids as unique phytochemical markers of Robusta being present in the same quantity and distribution in C. liberica as well. Gardeniae Fructus samples (fruits of Gardenia jasminoides) have additionally been characterized as this matrix is recognized as one of the few naturally occurring SiQA sources. The SiQA regioisomer content (total SiQA about 80 mg/100 mg) fully supports the proposal to use this matrix as a surrogate standard for further studies. [ABSTRACT FROM AUTHOR]

BACKGROUND: The effects of the environment and genotype in the coffee bean chemical composition were studied using nine trials covering an altitudinal gradient [600–1100 m above sea level (a.s.l.)] with three genotypes of Coffea arabica in the northwest mountainous region of Vietnam. The impacts of the climatic conditions on bean physical characteristics and chemical composition were assessed. RESULTS: We showed that the environment had a significant effect on the bean density and on all bean chemical compounds. The environment effect was stronger than the genotype and genotype‐environment interaction effects for cafestol, kahweol, arachidic (C20:0), behenic acid (C22:0), 2,3‐butanediol, 2‐methyl‐2‐buten‐1‐ol, benzaldehyde, benzene ethanol, butyrolactone, decane, dodecane, ethanol, pentanoic acid, and phenylacetaldehyde bean content. A 2 °C increase in temperature had more influence on bean chemical compounds than a 100 mm increase in soil water content. Temperature was positively correlated with lipids and volatile compounds. With an innovative method using iterative moving averages, we showed that correlation of temperature, vapour pressure deficit (VPD) and rainfall with lipids and volatiles was higher between the 10th and 20th weeks after flowering highlighting this period as crucial for the synthesis of these chemicals. Genotype specific responses were evidenced and could be considered in future breeding programmes to maintain coffee beverage quality in the midst of climate change. CONCLUSION: This first study of the effect of the genotype–environment interactions on chemical compounds enhances our understanding of the sensitivity of coffee quality to genotype environment interactions during bean development. This work addresses the growing concern of the effect of climate change on speciality crops and more specifically coffee. © 2023 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

The synthesis of four isomers of p -coumaroylquinic acids was performed by esterification of p -acetylcoumaroylchloride with a suitably protected (−)-quinic acid. All isomers have been characterized by means of NMR spectroscopy and circular dichroism. Acyl migration was observed in the synthesis of 3- O - p -coumaroylquinic acid and 4- O - p -coumaroylquinic acid. Calculations on the most stable conformations of all isomers have also been performed to explain the acyl migration observed during the synthesis procedure. [ABSTRACT FROM AUTHOR]

Green coffee beans are particularly rich in chlorogenic acids (CGAs), and their identification and quantification are usually performed by HPLC, coupled with mass spectrometry (LC-MS). Although there are a few examples of molecularly imprinted polymers (MIPs) for chlorogenic acid (5-CQA) recognition present in the literature, none of them are based on optical fluorescence, which is very interesting given its great sensitivity. In the present manuscript, fluorescent polymeric imprinted nanoparticles were synthetized following the non-covalent approach using hydrogenated 5-O-caffeoylquinic acid (H-5-CQA) as the template. The capability of the polymer to bind 5-CQA was evaluated by HPLC and fluorescence. A real sample of coffee extract was also analyzed to verify the selectivity of the polymer. Polymer fMIP01, containing 4-vinylpyridine and a naphtalimide derivative as monomers, showed a good response to the fluorescence quenching in the range 39 μM–80 mM. In the real sample, fMIP01 was able to selectively bind 5-CQA, while caffeine was not recognized. To demonstrate this, there is a promising system that can be exploited in the design of an optical sensor for 5-CQA detection. Polymer fMIP01 was immobilized by physical entrapment on a functionalized glass surface, showing a quenching of fluorescence with an increase of the CGA concentration between 156 μM and 40 mM. [ABSTRACT FROM AUTHOR]

A simple laboratory procedure for the isolation of pure cafestol and 16- O -methylcafestol together with β-sitosterol from coffee is disclosed. Cafestol and 16- O -methylcafestol have been exhaustively characterized through 1D and 2D 1 H, 13 C NMR, CD and X-ray diffraction. For the first time, the molecular structure of cafestol is reported and the assignment of the absolute configuration is unequivocally given by exploiting anomalous scattering of a brominated derivative. [ABSTRACT FROM AUTHOR]

Cafestol and 16- O -methylcafestol are diterpenes present in coffee, but whilst cafestol is found in both Coffea canephora and Coffea arabica , 16- O -methylcafestol (16-OMC) was reported to be specific of only C. canephora . The interactions of such compounds, with serum albumins, have been studied. Three albumins have been considered, namely human serum albumin (HSA), fatty acid free HSA (ffHSA) and bovine serum albumin (BSA). The proteins interact with the diterpenes at the interface between Sudlow site I and the fatty acid binding site 6 in a very peculiar way, leading to a significant change in the secondary structure. The diterpenes do not displace reference binding drugs of site 2, but rather they enhance the affinity of the site for the drugs. They, therefore, may alter the pharmacokinetic profile of albumin – bound drugs. [ABSTRACT FROM AUTHOR]

The first step in caffeine metabolism is mediated for over 95% by the CYP1A2 isoform of cytochrome P450. Therefore, CYP1A2 activity is most conveniently measured through the determination of caffeine clearance. The HPLC quantification of caffeine is fully validated and is the most widely used method. It can be performed on saliva, which is gaining importance as a diagnostic biofluid and permits easy and low invasive sampling. Here, we present a quantitative 1 H nuclear magnetic resonance (NMR) method to determine caffeine in human saliva. The procedure is simple because it involves only an ultra-filtration step and a direct extraction in a deuterated solvent, yielding a matrix that is then analyzed. The reliability of this NMR method was demonstrated in terms of linearity, accuracy, recovery, and limits of detection (LoD). Good precision (relative standard deviation, RSD <4%), a recovery of >95% and LoD of 6.8·10 −7 mol L −1 were obtained. The method was applied to samples collected from different volunteers over 24 h following a single oral dose of about 100 mg of caffeine administered with either coffee beverage or a capsule. [ABSTRACT FROM AUTHOR]

Neurotoxic and carcinogenic acrylamide (ACR) is present in many food products. This finding spurred numerous studies for ACR scavengers. Niacin is putatively one of them because it reacts via Michael addition with ACR to form 1-propanamide-3-carboxy pyridinium. Here, we study the mechanism and energetics of this reaction in aqueous solution by density functional theory. The CAM-B3LYP and M06-2X functionals with the 6-31+G(d,p) basis set and implicit solvent were used. Single point calculations at the MP2 level with the same basis set were performed on optimized structures obtained at the M06-2X level. Solvent effects comprehended both polarizable continuum model and solvation model density solvation models. The calculated NMR chemical shifts of 1-propanamide-3-carboxy pyridinium are in agreement with experimental results. The theoretical study favors thermodynamically the formation of the adduct while the calculated activation energies turn out not to be too dissimilar from the ones measured for the alkylation reaction between ACR and 4( p-nitrobenzyl)pyridine. © 2014 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]

• Nutritional composition of coffee silverskin (CSS) from arabica coffee. • Comprehensive assessment of macrominerals (7) and microminerals (23) in CSS. • Vitamin B 3 (2.51–3.07 µg/g) and vitamin B 2 (0.18–0.20 µg/g) are present in CSS. • Phytosterols analysis revealed high levels of β-sitosterol (77.1 ± 2.8 mg/kg). The present study assessed the nutritional composition of coffee silverskin (CSS) obtained from arabica roasted coffee. Following validated analytical methods, CSS resulted to be a high source of proteins (14.2 g/100 g) and dietary fibers (51.5 g/100 g). Moreover, the mineral analysis revealed high contents of calcium (1.1 g/100 g) and potassium (1.0 g/100 g). To date, this study provided the widest mineral profile of CSS with 30 minerals targeted including 23 microminerals with high levels of iron (238.0 mg/kg), manganese (46.7 mg/kg), copper (37.9 mg/kg), and zinc (31.9 mg/kg). Moreover, vitamins B 2 (0.18–0.2 mg/kg) and B 3 (2.5–3.1 mg/kg) were studied and reported for the first time in CSS. β-sitosterol (77.1 mg/kg), campesterol, stigmasterol, and Δ5-avenasterol, were also observed from the phytosterol analysis of CSS with a total level of 98.4 mg/kg. This rich nutritional profile highlights the potential values of CSS for innovative reuses in bioactive ingredients development. [ABSTRACT FROM AUTHOR]

The annual generation of coffee waste has overtaken 6 million metric tons, becoming a serious environmental problem. Herein, we report the fabrication of bimetallic electrocatalysts synthesized by 1) pyrolyzing spent coffee grounds (SCGs) at 400, 600, 800 and 1000 °C, 2) activating the as-obtained char with KOH and 3) functionalizing the activated carbon with iron(II) and manganese(II) phthalocyanine. The final electrocatalysts showed a high degree of amorphousness, defectivity (increasing with temperature) and high specific surface area (up to 1820 m2 g−1). In half-cell compartment (0.1 M KOH electrolyte), the top-notch material in terms of oxygen reduction reaction (ORR) activity and selectivity was CFeMn_600, which showed the same half-wave potential (E 1/2) compared to Pt/C standard along with a lower peroxide production. These outstanding results could be attributed to a high surface area, a Fe-Mn synergy, and an abundance of C-N defects. The performance of CFeMn_600 as a cathode material in alkaline exchange membrane fuel cells (AEMFC) showed an open circuit voltage (OCV) of 0.890 V and power density of 30 mW cm−2. Notwithstanding, this research is one of few cases where a waste-derived electrocatalyst is tested in a real AEMFC, thus becoming a pioneer in the fuel cell study of waste-derived electrode materials. [ABSTRACT FROM AUTHOR]

Abstract: In this work, we show how an extensive and fast quantification of the main components in green coffee oil can be achieved by NMR, with minimal sample manipulation and use of organic solvents. The approach is based on the integration of characteristic NMR signals, selected because of their similar relaxation properties and because they fall in similar spectral regions, which minimizes offset effects. Quantification of glycerides, together with their fatty acid components (oleic, linoleic, linolenic and saturated) and minor species (caffeine, cafestol, kahweol and 16-O-methylcafestol), is achieved in less than 1h making use of 1H and 13C spectroscopy. The compositional data obtained are in reasonable agreement with classical chromatographic analyses. [Copyright &y& Elsevier]

Abstract: An arabinogalactan-protein (AGP) composed of d-galactose and l-arabinose in 9:1mol proportion containing about 1.6% of protein has been isolated from the instant coffee powder of roasted Coffea arabica beans by water extraction followed by barium hydroxide and ethanol precipitations. AGP was recovered in 3.2% yield of instant coffee powder and its average molecular mass was significantly decreased due to severe manufacturing conditions to 5400. Chemical and spectroscopic studies on the instant coffee AGP revealed a β-(1,3)-linked Galp backbone branched at C6 by side 6-linked Galp residues terminated by Araf and/or Galp and confirming thus an α-arabino-3,6-β-galactan in the instant coffee powder composite. It has been found that about 74% of branched 3,6-linked Galp residues have their origin in the backbone while 26% is located in side chains (6-linked Gal units substituted at C3 by Araf or terminal Galp units). Moreover, about 11% of Galp residues involved in linear 1,6-linkages of AGP side chains survived a severe industrial process. [Copyright &y& Elsevier]

Parallel extraction of instant coffee powder prepared from roasted beans of Coffea arabica by industrial process according to the procedure of Wolfrom and Anderson afforded two arabinogalactan-protein isolates, i.e. AG1 and AG2 in yields of 14.6% and 14.4% of a crude polysaccharide complex A (w/w), respectively. However, their yields were about twice lower in comparison with AG isolation described by Wolfrom and Anderson forty years ago. Stronger roasting and extraction conditions during the industrial process used at that time for producing instant coffee powder used for AG isolation are supposed to be the main reason. This conclusion is supported by the fact that molecular masses of newly isolated arabinogalactans AG1 and AG2 were higher (5 200-5 400) then that of arabinogalactan isolated in the past (1 800 only). The presence of proteins in AG1 and AG2 suggests that these polysaccharides are present in the form of arabinogalactan-protein. Saccharide analysis of both polysaccharides showed similar composition: over 85% of galactose and 8% of arabinose residues, accompanied by smaller amounts of sugars as contaminants, which were not determined in previous isolation. Identical structure of both arabinogalactan-proteins was confirmed on the basis of 1H and 13C NMR spectra. [ABSTRACT FROM AUTHOR]

Stationary phase based on tris(3,5-dimethylphenylcarbamoyl) cellulose is prepared under various conditions (precipitation, evaporation, sieving), and examined in HPLC columns for enantioseparation of racemic mixtures 1–10. Number of theoretical plates (N) and separation parameters (α and RS) are compared with those obtained with commercially available column based on the same polymeric material (Chiralcel OD, from Daicel Co.). Higher efficiency of the columns prepared by precipitation under specific conditions and followed by sieving of stationary phase, over those prepared by evaporation and (or without) sieving, is demonstrated. [ABSTRACT FROM AUTHOR]

Coffee diterpenes are the main constituents of the coffee oil unsaponifiable fraction. The three most important diterpenes are cafestol, kahweol, and 16‐O‐methylcafestol (16‐OMC), and they are produced, except for cafestol, only by plants of the Coffea genus. Recently, in addition to these three major diterpenes, another 16‐O‐methylated diterpene (16‐O‐methylkahweol: 16‐OMK) has been identified and quantified, for the first time, in Robusta coffee. For many years, 16‐OMC has been considered present exclusively in Robusta, and so it has been reputed an excellent authenticity marker for the presence of Robusta in coffee products. For its quantification, nuclear magnetic resonance (NMR) has proved very useful when compared with other methods. Quite recently, the detection of very low levels of the two 16‐O‐methylated diterpenes (16‐OMD) 16‐OMC and 16‐OMK in roasted Arabica was reported. This finding makes the use of NMR methods in 16‐OMD quantification in Arabica coffee particularly challenging in view of both the trace amounts of 16‐OMD and the impossibility to discriminate between 16‐OMC and 16‐OMK. The ultra‐high performance liquid chromatography mass spectrometry (UHPLC‐MS) method, already used to detect 16‐OMC and 16‐OMK in Arabica roasted coffee, is then more suitable for quantitative analyses. Up to now however, no quantification of coffee 16‐OMD via ultra‐high performance liquid chromatography tandem mass spectrometry (UHPLC‐MS/MS) has been carried out; this largely stimulated the present study. For the first time, a simple procedure for the quantitative detection of 16‐OMD in Arabica coffee has been developed, and as far as 16‐OMC is concerned, fully validated in terms of specificity, linearity, concentration range, limit of detection (LOD), limit of quantification (LOQ), and repeatability following the criteria specified in the EU Commission Decision 2002/675/EC. This method proved to be very specific and sensitive. In order to avoid the chemical complexity generated by the roasting process, the method was optimized and validated on several green Arabica samples from different geographical origins. [ABSTRACT FROM AUTHOR]

Chlorogenic acids (CGAs) are a large class of esters formed between quinic acid and hydroxycinnamic acids. They are present in coffee as a complex mixture of positional and geometric isomers, where caffeoylquinic acids (CQAs) are the most abundant, followed by dicaffeoylquinic acids (diCQAs), feruloylquinic acids (FQAs), and p‐coumaroylquinic acids (p‐CoQAs). The aim of this work is to develop a new reliable and fast liquid chromatography–tandem mass spectrometry (LC–MS/MS) method for simultaneous identification and quantification of total amount of 11 CGAs in roasted coffee. Regarding sample preparation step, aqueous methanol and 100% aqueous ultrasonic extractions were evaluated. For the filtration Step 4, different membranes were tested, in order to fill the void of complete evaluation of extractables recovery when using different membranes, highlighting an incomplete recovery when using nylon filters. An LC/electrospray ionization (ESI)–MS/MS method was developed and validated following the European rules in terms of specificity, linearity, concentration range, limit of detection (LOD) and limit of quantification (LOQ), precision, and trueness, in order to obtain a useful quality control tool for roasted coffee. The method was applied for quantification of CGAs of a roasted coffee sample previously characterized by an interlaboratory circuit (LVU), and results were compared with the quantitation of CGAs via UHPLC‐DAD. The quantitative results were expressed as 5‐CQA equivalents, and the validation of this approach opens the way to reliable, cheap, and environmental‐friendly tools for quality control purposes. [ABSTRACT FROM AUTHOR]

• Silverskin can be used as raw material for the recovery of functional compounds. • A new HPLC-MS/MS method has been developed for 30 bioactive compounds of different subclasses. • The monitored bioactive compounds represent 1.6–4% of silverskin extracts. • Silverskin extracts play a potential role as protective agents against neurodegeneration. The research of value-added applications for coffee silverskin (CSS) requires studies to investigate potential bioactive compounds and biological activities in CSS extracts. In this study, different ultrasound‐assisted extraction (UAE) methods have been tested to extract bioactive compounds from CSS. The obtained extracts, were characterized using a new HPLC-MS/MS method to detect and quantify 30 bioactive compounds of 2 classes: alkaloids and polyphenols (including phenolic acids, flavonoids, and secoiridoids). CSS extracts obtained with ethanol/water (70:30) as extraction solvent showed the highest levels (p ≤ 0.05) of bioactive compounds (4.01 ± 0.34% w/w). High content of caffeine was observed with levels varying from 1.00% to 3.59% of dry weight of extract (dw). 18 phenolic compounds were detected in CSS extracts with caffeoylquinic acids (3-CQA, 5-CQA and 3,5-diCQA) as the most abundant polyphenols (3115.6 µg g to –5444.0 µg g−1). This study is also one of the first to characterize in-depth flavonoids in CSS revealing the levels of different flavonoids compounds such as rutin (1.63–8.70 µg g−1), quercetin (1.53–2.46 µg g−1), kaempferol (0.76–1.66 µg g−1) and quercitrin (0.15–0.51 µg g−1). Neuroprotective activity of silverskin extracts against H 2 O 2 -induced damage was evaluated for the first time suggesting for methanol and ethanol/water (70:30) extracts a potential role as protective agents against neurodegeneration due to their ability to counteract oxidative stress and maintain cell viability. Silverskin extracts were not inhibiting the growth of anyone of the bacterial species included in this study but data obtained by water extract might deserve a deeper future investigation on biofilm-related activities, such as quorum sensing or virulence factors' expression. From their composition and their evidenced biological activities, CSS extracts could represent valuable ingredients in nutraceutical formulations. [ABSTRACT FROM AUTHOR]

Conventional American cultivars of coffee are no longer adapted to global warming. Finding highly productive and stable cultivars in different environments without neglecting quality characteristics has become a priority for breeders. In this study, new Arabica F1 hybrids clones were compared to conventional American varieties in seven contrasting environments, for yield, rust incidence and volume of the canopy. The quality was assessed through size, weight of 100 beans, biochemical analysis (24 aroma precursors and 31 volatiles compounds) and sensory analysis. Conventional varieties were the least productive, producing 50% less than the best hybrid. The AMMI model analysis pointed out five hybrids as the most stable and productive. Two F1 hybrids clones, H1-Centroamericano and H16-Mundo Maya, were superior to the most planted American cultivar in Latin and Central America showing a high yield performance and stability performance. H1-Centroamerica and Starmaya contain more d-limonene than Caturra, while Starmaya contain more 3-methylbutanoic acid than the control. Those two latter volatiles compounds are linked with good cup quality in previous studies. In terms of sensory analysis, Starmaya and H1-Centroamericano scored better than control. [ABSTRACT FROM AUTHOR]

The genome of the allotetraploid species Coffea arabica L. was sequenced to assemble independently the two component subgenomes (putatively deriving from C. canephora and C. eugenioides) and to perform a genome-wide analysis of the genetic diversity in cultivated coffee germplasm and in wild populations growing in the center of origin of the species. We assembled a total length of 1.536 Gbp, 444 Mb and 527 Mb of which were assigned to the canephora and eugenioides subgenomes, respectively, and predicted 46,562 gene models, 21,254 and 22,888 of which were assigned to the canephora and to the eugeniodes subgenome, respectively. Through a genome-wide SNP genotyping of 736 C. arabica accessions, we analyzed the genetic diversity in the species and its relationship with geographic distribution and historical records. We observed a weak population structure due to low-frequency derived alleles and highly negative values of Taijma's D, suggesting a recent and severe bottleneck, most likely resulting from a single event of polyploidization, not only for the cultivated germplasm but also for the entire species. This conclusion is strongly supported by forward simulations of mutation accumulation. However, PCA revealed a cline of genetic diversity reflecting a west-to-east geographical distribution from the center of origin in East Africa to the Arabian Peninsula. The extremely low levels of variation observed in the species, as a consequence of the polyploidization event, make the exploitation of diversity within the species for breeding purposes less interesting than in most crop species and stress the need for introgression of new variability from the diploid progenitors. [ABSTRACT FROM AUTHOR]

Highlights • p- coumaroylquinic acids UHPLC analyses in wild coffees reported for the first time. • Use of authentic standards for identification of p CoQAs. • Total CGAs contents and measure of contribution of p CoQAs to polyphenols in coffee. • C. sessiliflora is the richest source of p CoQAs. • Effect of roasting conditions on p CoQAs content of two commercial species. Abstract Quantitative analyses of mono- p -coumaroylquinic acids (p CoQAs) and total chlorogenic acids (CGAs) in green coffee commercial lots of C. arabica, C. canephora and C. liberica from different geographical origins and eight wild Coffea species were carried out. Among the commercial lots, p CoQAs average content of C. arabica (0.67 mg/g) is higher than that of C. canephora (0.40 mg/g) being C. liberica intermediate (0.58 mg/g). As far as the analyzed wild Coffea species is concerned, C. pseudozanguebariae is characterized by the lower p CoQAs content (0.12 mg/g) whereas C. sessiliflora is by far the richest source of p CoQAs (2.18 mg/g). Effect of the roasting process on the mono- p -coumaroylquinic acids profile was evaluated for the economically exploited species C. arabica and C. canephora. For the first time distribution of mono- p- coumaroylquinic acid isomers in wild coffee species by fast and accurate UHPLC-DAD analyses using authentic standards previously synthetized, is reported. [ABSTRACT FROM AUTHOR]

The high cost and environmental impact of fossil-based organic carriers represent a critical bottleneck to their use in large-scale industrial processes. The present study demonstrates the applicability of rice husk as inexpensive renewable carrier for the immobilization of enzymes applicable sectors where the covalent anchorage of the protein is a pre-requisite for preventing protein contamination while assuring the recyclability. Rice husk was oxidized and then functionalized with a di-amino spacer. The morphological characterization shed light on the properties that affect the functionalization processes. Lipase B from Candida antarctica (CaLB) and two commercial asparaginases were immobilized covalently achieving higher immobilization yield than previously reported. All enzymes were immobilized also on commercial epoxy methacrylic resins and the CaLB immobilized on rice husk demonstrated a higher efficiency in the solvent-free polycondensation of dimethylitaconate. CaLB on rice husk appears particularly suitable for applications in highly viscous processes because of the unusual combination of its low density and remarkable mechanical robustness. In the case of the two asparaginases, the biocatalyst immobilized on rice husk performed in aqueous solution at least as efficiently as the enzyme immobilized on methacrylic resins, although the rice husk loaded a lower amount of protein. [ABSTRACT FROM AUTHOR]

Abstract: Proton transfer reaction (PTR)‐time of fight (ToF)‐mass spectrometry (MS) has been recently employed as a quick, easy, and sensitive alternative to gas chromatography MS for the analysis of volatile compounds in food. In the present work, PTR‐ToF‐MS was applied to the characterization of the volatile profiles of the baked and toasted crumbs and crusts of 5 gluten‐free breads elaborated with quinoa, teff, and rice flours as well as corn and wheat starches and wheat bread as a control samples. Two hundred fifty‐nine peaks (m/z) were detected, 86 peaks were tentatively identified, and 56 volatile compounds were selected as important contributors to bread aroma. Fast gas chromatography PTR‐ToF‐MS analyses were performed with 42 standards to identify them in the baked crumbs and crusts, 18 of them being present in all the samples. From the baked samples, it was concluded that quinoa crust was the 1 with higher volatile compound in high abundance, characterized by volatile compounds from fermentation, lipid oxidation, 2‐acetyl‐1‐pyrroline, and diethyl‐pyrazines, while wheat crust was characterized by the highest content in furan derivatives. The toasting time led to crust samples with an increased content in all the volatile compounds: Quinoa crust was now characterized by the highest content in all the pyrazines and furan derivatives, while starches were distinguished by the highest abundance in 2‐acetyl‐1‐pyrroline and diethyl‐pyrazines. Neither the baked crumbs nor the toasted crumbs presented the highest content in none of the volatile compounds. Therefore, it was concluded that quinoa flour can be a suitable alternative for the elaboration of baked and toasted breads due to the high content of pleasant volatile compounds from fermentation, the key volatile in crust 2‐acetyl‐1‐pyrroline (baked sample), as well as pleasant pyrazines and toasted‐like furan derivatives (baked and toasted samples); however, the off‐flavor volatile compounds from lipid oxidation as well as the bitter saponins present in quinoa bread should be taken into account. [ABSTRACT FROM AUTHOR]

Abstract: Chlorogenic acids are relevant coffee quality markers, taste, and aroma precursors as well as important bioactive compounds. A number of mono‐acyl, di‐acyl, and tri‐acyl quinic acid isomers were found in green coffee beans, being mono‐caffeoyl, mono‐feruloyl, mono‐p‐coumaroyl, and di‐caffeoylquinic acid isomers considered as quantitatively major compounds. Roasting process increases the chemical complexity of coffee by inducing the formation of a number of lactones (quinides), shikimates, and other chlorogenic acids derivatives. So far, little attention has been paid in characterizing minor chlorogenic acids and derivatives in roasted Coffea arabica, also known as Arabica. In the present work, roasted C. arabica samples from different geographical origins (Brazil, Colombia, Costa Rica, Ethiopia, Guatemala, and India) were characterized by UHPLC‐ESI‐QqTOF‐MS/MS. Several minor chlorogenic acid isomers were identified. In particular, HR‐MS/MS provided putative identification of four dimethoxycinnamoyl‐quinic acid derivatives, such as 4‐dimethoxycinnamoylquinic acid, 4‐dimethoxycinnamoyl‐3‐caffeoylquinic acid, 3‐dimethoxycinnamoyl‐4‐feruloylquinic acid, 4‐dimethoxycinnamoyl‐5‐feruloylquinic acid, and two caffeoyl, feruloyl quinic acid derivatives (3‐caffeoyl‐4‐feruloylquinic acid and 3‐feruloyl‐4‐caffeoylquinic acid). To our knowledge, these compounds were found in roasted Arabica coffee for the first time, and their presence is independent on the different geographical origins examined. [ABSTRACT FROM AUTHOR]

Amperometric biosensor utilizing FAD-dependent glucose dehydrogenase (FAD-GDH) for a specific sucrose monitoring in green coffee is described. FAD-GDH was co-immobilized with invertase and mutarotase on a thin-layer gold planar electrode using chitosan. The biosensor showed a wide linearity (from 10 to 1200 μM), low detection limit (8.4 μM), fast response time (50 s), and appeared to be O2 independent. In addition the biosensors exhibited a good operational (3 days) and storage (1 year) stability. Finally, the results achieved from the biosensor measurements of sucrose in 17 samples of green coffee (Coffea arabica, C. canephora and C. liberica) were compared with those obtained by the standard HPLC method. The good correlation among results of real samples, satisfactory analytical performance and simple use of the presented biosensor make it suitable for application in coffee industry. [ABSTRACT FROM AUTHOR]

The antimicrobial activity of a regular and decaffeinated Arabica coffee extract was evaluated against three different Gram-positive bacteria and two Gram-negatives, including pathogenic Staphylococci strains. The antimicrobial activity was shown to be independent from caffeine content and was more pronounced against the Gram-positive strains. The regular coffee extract exhibited a significant bacteriostatic effect against Staphylococcus aureus and Staphylococcus epidermidis at short exposure times and became bactericidal after prolonged exposure. The potential cytotoxicity of the regular coffee extract was also evaluated towards breast adenocarcinoma MCF7 cells, showing to become significant only after 24 h exposure and at a higher concentration than that producing the antibacterial effect. These results highlight the potential of coffee extracts as a naturally active and non-toxic antibacterial compound suitable for biomedical applications. [ABSTRACT FROM AUTHOR]

The headspace of six roasted Coffea arabica coffees, both brew and powder, of different geographical origins (Brazil, Ethiopia, Guatemala, Costa Rica, Colombia, and India) was analysed by Proton Transfer Reaction-Time of Flight-Mass Spectrometry. For the first time, in the case of coffee, a Switching Reagent Ion System has been used to produce different ionisation agents: H 3 O + , NO + and O 2 + . Significant differences were found among volatile concentrations for the different origins both for powders and brews, in particular high concentrations of terpenes for Ethiopia, sulphur compounds for Colombia and thiazoles for Brazil and India. Effective classification models have been set for the different ionisation modes and data fusion of the data obtained by different reagent ions further reduced the classification errors. [ABSTRACT FROM AUTHOR]

The first goal of this work was to gain insight into the mechanism underlying flavour perception and aroma release by coupling two real-time methods: Temporal Dominance of Sensations (TDS) and nosespace (NS) analysis via Proton Transfer Reaction–Time of Flight–Mass Spectrometry (PTR–ToF–MS). The second goal was to investigate the impact of roasting degree and sugar addition on aroma release and perception in espresso coffee. A set of four coffee samples, two roasting degrees and two sugar levels, has been used for both sensory and instrumental measurements. The in-mouth flavour evolution in terms of dominant sensations was measured by mean of TDS carried out by 18 trained judges with a 9-attribute list ( Sweet , Sour , Bitter , Astringent , Roasted , Burnt , Caramel , Nutty and Vegetal ). The same judges were subjected simultaneously to NS analysis in order to identify and quantify the volatile compounds reaching their olfactory receptors during coffee consumption. A significant effect of roasting was observed with both techniques. More compounds and in larger quantity were released when increasing roasting degree, which was described sensorially as a greater dominance of the attributes Burnt , Roasted , Astringent and Bitter . Sugar addition did not significantly affect the aroma release of volatile compounds as demonstrated by the NS profiles of judges while changing completely the way the coffee was sensorially perceived in mouth. As expected, sweet taste became dominant over bitter and sour but it increased more globally the flavour complexity with Caramel and Nutty notes reducing the Roasted or Burnt ones. This result emphasises the presence of taste–smell perceptual interactions, due to congruence effect between sweet taste and some flavours of coffee, and the potentialities of this combination of dynamic methods to study them. Besides, the treatment of NS data using clustering methods revealed two different release behaviours, which permitted to identify potential TDS markers. [ABSTRACT FROM AUTHOR]

Characterisation of coffees according to their origins is of utmost importance for commercial qualification. In this study, the aroma profiles of different batches of three monoorigin roasted Coffea arabica coffees (Brazil, Ethiopia and Guatemala) were analysed by Proton-Transfer-Reaction-Time of Flight-Mass Spectrometry (PTR-ToF-MS). The measurements were performed with the aid of a multipurpose autosampler. Unsupervised and supervised multivariate data analysis techniques were applied in order to visualise data and classify the coffees according to origin. Significant differences were found in volatile profiles of coffees. Principal component analysis allowed visualising a separation of the three coffees according to geographic origin and further partial least square regression-discriminant analysis classification showed completely correct predictions. Remarkably, the samples of one batch could be used as training set to predict geographic origin of the samples of the other batch, suggesting the possibility to predict further batches in coffee production by means of the same approach. Tentative identification of mass peaks aided characterisation of aroma fractions. Classification pinpointed some volatile compounds important for discrimination of coffees. Copyright © 2014 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Highlights: [•] Nosespace analysis by PTR-ToF-MS was applied to the study of three coffees. [•] Differences among samples were encountered when different roast degrees were compared. [•] Reproducible and relevant differences between panelists were observed. [•] PTR-ToF-MS was proven to be useful in the characterization of sensory panels. [Copyright &y& Elsevier]