1,721,044 research outputs found
Isolation and characterization of major diterpenes from C. canephora roasted coffee oil
Full text linkA simple laboratory procedure for the isolation of pure cafestol and 16-O-methylcafestol together with beta-sitosterol from coffee is disclosed. Cafestol and 16-O-methylcafestol have been exhaustively characterized through 1D and 2D H-1, C-13 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
Interaction of coffee compounds with serum albumins. Part II: Diterpenes
Full text linkCafestol 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
Are taste variations associated with the liking of sweetened and unsweetened coffee?
No full textObjective: In this study, we evaluated the influence of taste phenotypes and genotypes on the hedonics of sweetened and unsweetened coffee. Methods: Liking of espresso coffee from food questionnaire and of a ready-to-drink unsweetened coffee beverage was measured using a 9-point hedonic scale in 1551 Italian individuals. Perception and liking for different bitter and sweet compounds were also collected. Genotyping of selected Single Nucleotide Polymorphisms (SNPs) in five taste genes (TAS1R3, GNAT3, TAS2R14, TAS2R19, TAS2R38) was performed. Linear and logistic regression models, including sex and gender as covariates, were used to test the relationship of taste phenotypes and selected SNPs with coffee liking. Results: We found that increased caffeine bitterness perception was associated with an increasing liking for sweetened coffee (p-value = 0.018) and decreased liking of unsweetened coffee (p-value = 0.034). The liking of unsweetened coffee beverage was also negatively associated with sweet intensity perception (p-value = 0.03). Analysis of SNPs in taste-related genes showed that rs6467192 G allele (intron 4 variant) in GNAT3 sweet taste gene was associated with higher liking of sweetened coffee (p-value = 0.002) and lower liking of unsweetened coffee (p-value = 0.01). An association also emerged between unsweetened coffee and SNPs in bitter receptor genes, with rs2597979 in TAS2R14 gene associated with liking of unsweetened coffee (p-value = 0.004) and rs10772420 in TAS2R19 gene associated with liking of both unsweetened espresso coffee and coffee beverage (p-value = 0.04 and p-value = 0.03, respectively). Conclusion: These findings suggested that individual preference for sweetened and unsweetened coffee may be influenced by both phenotypic and nucleotide variations in bitter and sweet taste sensitivity
Poly(3-hydroxybutyrate-Co-3-hydroxyvalerate) (PHBV) Based Biocomposites Containing Coffee Silverskin: Injection Moulding and Migration Performances Assessment
No full textPoly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) is among the most attracting low environmental impact polymeric materials. Coffee Silverskin (CS), an agro-food residue, has been compounded in variable amounts into a PHBV matrix in the presence of acetyl tributyl citrate (ATBC) as plasticizer, and calcium carbonate (CaCO3) as filler, to produce biocomposites through a pre-industrial scale melt extrusion technique. Thermal, morphological and mechanical properties have been investigated in order to validate whether these PHBV/CS based biocomposites could be used to manufacture moulded items, e.g. coffee capsules body. The increasing concentration of CS in PHBV improves the stiffness and the heat deflection temperature properties of the biocomposites. Coffee capsules body have been produced by injection moulding starting from the optimized formulations, based on the PHBV/CS system, and were characterized in terms of migration properties in contact with simulants. Notably, the overall migration at 100 °C was below the limit (10 mg/dm2) required for plastic materials in food contact applications
Arabica coffee extract shows antibacterial activity against Staphylococcus epidermidis and Enterococcus faecalis and low toxicity towards a human cell line
Full text linkThe 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 24h 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
A protocol for the development and maintenance of Coffea arabica (L.) cell suspension cultures
Full text linkCoffea spp. are remarkable sources of phytochemicals, but the lack of a well-defined culture medium aimed at the induction of non-embryogenic and friable callus hampers the establishment of plant cell suspension cultures for large-scale production of valuable compounds. In this paper, we describe a one-medium protocol suitable to obtain both callus and cell suspension cultures from leaves of two elite cultivars of C. arabica. The protocol was developed through an iterative process involving the determination of the best concentration of auxin and cytokinin, their optimal ratio, as well as the most effective molecule of either hormone class. Young leaves were found to be a good and easy-to-use explant source for callus induction and proliferation, provided that a cytokinin was present in association with a chlorinated auxin in a full
strength, semi-solid MS medium. The best results were obtained by hormone concentration and combination of 1 mg/L of both kinetin and 2,4,5-trichlorophenoxyacetic acid. The same ratio of these growth regulators was conveniently used for the development and stabilization of cell suspension cultures in liquid MS medium. When grown in darkness, stabilized suspension cultures showed a fine and homogeneous texture, with a 10-fold biomass increase within 25 days and a cell viability > 90%. In addition, the phytochemical profile revealed the presence of the most widely studied coffee compounds. The protocol can be applied to obtain adequate amounts of cell biomass for use in physiological studies concerning the
production of secondary metabolites
Quantification of isoflavones in coffee by using solid phase extraction (SPE) and highperformance liquid chromatography–tandem mass spectrometry (HPLC-MS/MS)
No full textA 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 l1 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 l1 and 0.05–1 μg l1, 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 l1 and from 0.58 to 3.26 μg l1 in ECs and from 0.36 to
4.27 μgkg1 and from 0.71 to 3.95 μgkg1 in ground coffees. This method confirms the high specificity and selectivity of
MS/MS systems for detecting bioactives in complex matrices such as coffee
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
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