262,285 research outputs found
Kinetics of volatile organic compounds (VOCs) released by roasted Coffee during the first ten days after processing
No full textThe quality of coffee is linked to the aroma created by the chemical reactions that occur during the roasting process. While it is generally thought that roasted coffee is a stable product with a relatively long shelf-life, little information is available on the evolution (kinetic) of the volatile organic compounds (VOCs) in the days immediately following the process. The aim of this study is to determine the evolution of VOCs released by coffee beans, on samples of Coffea arabica (three different origins) and Coffea canephora (1 single origin), by using a Proton Transfer Reaction Time-of-Flight Mass Spectrometer (PTR-ToF-MS) 24 hours after roasting, and for the next 9 days. Results confirmed the differences already highlighted in previous studies between the VOCs spectra of the two species. There were also significant differences in the intensity of emissions for the different origins of Coffea arabica, with the highest VOCs amount over time always detected in the Honduras Arabica samples. The involved detected protonated ions were grouped into three classes: compounds (ppbv) present with decreasing quantity; weakly increasing; almost
constant trend; or always increasing. A complex dynamic emerged for the different protonated ions over time, which not only affects the mass spectra of the different species but also influences the configuration of the mass spectra of the different geographical zones of production
Covering the different steps of the coffee processing: Can headspace VOC emissions be exploited to successfully distinguish between Arabica and Robusta?
No full textThis work was performed to evaluate the possible application of PTR-ToF-MS technique in distinguishing between Coffea arabica (Arabica) and Coffea canephora var. robusta (Robusta) commercial stocks in each step of the processing chain (green beans, roasted beans, ground coffee, brews). volatile organic compounds (VOC) spectra from coffee samples of 7 Arabica and 6 Robusta commercial stocks were recorded and submitted to multivariate statistical analysis. Results clearly showed that, in each stage of the coffee processing, the volatile composition of coffee is highly influenced by the species. Actually, with the exception of green beans, PTR-ToF-MS technique was able to correctly recognize Arabica and Robusta samples. Particularly, among 134 tentatively identified VOCs, some masses (16 for roasted coffee, 12 for ground coffee and 12 for brewed coffee) were found to significantly discriminate the two species. Therefore, headspace VOC analyses was showed to represent a valuable tool to distinguish between Arabica and Robusta
Metabolic Responses in Leaves of 15 Italian Olive Cultivars in Correspondence to Variable Climatic Elements
No full textThis study aims to evaluate the metabolic changes that occurred in olive leaves as responses over time to variations in climatic elements. Rainfall, temperature, and solar radiation data were collected over 4 months (August–November) to assess the impact of different climatic trends on the metabolism of the leaves of 15 Italian olive cultivars, cultivated at the experimental farm of the University of Florence. The net photosynthetic rate (AN) and stomatal conductance (gs), measured as main indicators of primary metabolism, were mainly influenced by the “cultivar” effect compared to the “climate” effect. The lowest AN value was showed by “Bianchera”, while “Ascolana” recorded the highest (8.6 and 13.6 μmol CO2 m−2s−1, respectively). On the other hand, the secondary metabolism indicators, volatile organic compound (VOC) and oleuropein (OL) content, were much more influenced by climate trends, especially rainfall. A phase of high rainfall caused a significant increase in the VOCs emission from leaves, even with different behaviors among the genotypes. The highest differences were observed between “Maiatica di Ferrandina”, with the highest average values (~85,000 npcs), and “Frantoio”, which showed the lowest (~22,700 npcs). The OL content underwent considerable fluctuations in relation to the rainfall but also appeared to be controlled by the genotype. “Coratina” always showed the highest OL concentration (reaching the maximum ~98 mg g−1), indicating the great potential of this cultivar for the industrial recovery of OL
Going Beyond Counting First Authors in Author Co-citation Analysis
No full textThe 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
Simulation and optimization of electric vehicles’charge profiles
No full textThis paper analyzes the additional load introduced by
electric vehicles on the distribution grid. Mission
profiles recorded from real vehicles are used to simulate
the load of battery charges on the distribution grid. An
optimization model is proposed and used to evaluate the
effectiveness of variable rate tariffs
Aroma fingerprinting in green and roasted beans and ground coffee by Proton PTR-ToF-MS
No full textThe research is based on the utilization of the PTR-TOF-MS headspace analysis to distinguish, by VOCs, different matrices in coffee beans. Two species, Coffea arabica and Coffea canephora, contribute to the total production; the commercial value of the coffee depends on the species (Coffea arabica generally being considered of highest quality) and on geographical origin, including not only the pedoclimatic conditions, but also the processing systems (dry or wet).
Green beans, medium roasted beans and the related ground coffee of both C. arabica and C. canephora, coming respectively from 7 and 5 different geographical zones of Africa, America and Asia, were comparatively evaluated. By a PLS-DA analysis the green beans samples resulted sharply separated from the roasted beans and from the ground coffees, with a quantitative and qualitative increase of VOCs. The main protonated masses discriminating C. arabica from C. canephora were, in the green beans, m/z = 33.033 (tentatively identified as methanol), 49.010 (TI: methanethiol), 81.069 (TI: terpene fragment), 95.086 (TI: terpene fragment), 101.060 (TI: pentanedione) and, in the class of roasted beans, m/z = 69.033 (TI: furan), 85.028 (TI: furanone), 97.028 (TI: furfural), 111.045 (TI: acetilfuran), 141.055 (TI: furfurilacetate).
In the arabica group, roasted beans and ground coffee resulted very well distinguished, without regard of the country of production. The different Indian samples (two canephora and one arabica) were correctly classified. The separation between the two subgroups roasted beans and ground coffee was determined by quantitative differences of the same protonated masses, as m/z = 43.054 (TI: alkyl fragment), 61.028 (TI: acetic acid), 85.028 (TI: furanone), 148.076 (TI: furfurilpyrrole).
These results show that by the PTR-TOF-MS headspace VOCs analysis it is possible to check the correct attribution of the roasted beans and ground coffees to the right category (arabica or canephora), without regard of geographical origin of production
Unconventional and Sustainable Nanovectors for Phytohormone Delivery: Insights on Olea europaea
No full textNanoscience has allowed outstanding progress in many fields of research. Concerning the transport and delivery of active principles (drugs, contrast agents, sensitizers etc.), the improvements obtained by miniaturized carriers have recently been extended from medicine and pharmacy to agriculture. However, when coming to crop production, issues such as scalability, eco-compatibility, and sustainability represent a veritable challenge, so far only partially addressed. In this study, we propose lipid-based nanoformulations for the administration of root-promoting phytohormones to different cultivars of Olea europaea. In order to maximize the efficiency of these novel carriers, we devised nanovectors made by lipids extracted from olive pomace, a material derived from the plant itself and representing a waste in oil processing. This allowed combining cost-effectiveness and environmentally friendly procedures. The implementation obtained using adjuvants, such as purified natural lipids forming stable and well-defined nano-objects, was also investigated. Controlled and reproducible formulations were achieved after extensive study of the obtained systems, in particular by physicochemical characterization through advanced methods. Trials in vivo and in vitro showed that rooting was enhanced with respect to conventional treatments, thus indicating that the innovative formulations here fabricated have significant potentiality for the large-scale administration of agrochemicals in the context of sustainable economy
Protecting Animals 36: Author Witi Ihimaera
No full textIn this very special episode of Knowing Animals I am joined by beloved New Zealand author Witi Ihimaera. Witi has written many books featuring nonhuman animals. He offers us a non-colonial lens through which to think about the human/nonhuman relationship
Author Under Sail The Imagination of Jack London, 1893-1902
No full textIn Author Under Sail, Jay Williams offers the first complete literary biography of Jack London as a professional writer engaged in the labor of writing. It examines the authorial imagination in London's work, the use of imagination in both his fiction and nonfiction, and the ways he defined imagination in the creative process in his business dealings with his publishers, editors, and agents. In this first volume of a two-volume biography, Williams traverses the years 1893 to 1902, from London's "Story of a Typhoon" to The People of the Abyss. The Jack London who emerges in the pages of Author Under Sail is a writer whose partnership with publishers, most notably his productive alliance with George Brett of Macmillan, was one of the most formative in American literary history. London pioneered many author models during the heyday of realism and naturalism, blurring the boundaries of these popular genres by focusing on absorption and theatricality and the representation of the seen and unseen. London created an impassioned, sincere, and extremely personal realism unlike that of other American writers of the time. Author Under Sail is a literary tour de force that reveals the full range of London as writer, creative citizen, and entrepreneur at the same time it sheds light on the maverick side of machine-age literature.Intro -- Title Page -- Copyright Page -- Dedication -- Contents -- Acknowledgments -- Introduction -- 1. Spirit Truth -- 2. From Absorption to Theatricality and Back Again -- 3. "I Will Build a New Present" -- 4. Sons as Authors -- 5. Fathers as Publishers -- 6. The Daughter as Author -- 7. Lovers as Authors -- 8. At Sea with the Family -- 9. Yellow News, Yellow Stories -- 10. The Return Home -- Notes -- Bibliography -- Index -- About Jay WilliamsIn Author Under Sail, Jay Williams offers the first complete literary biography of Jack London as a professional writer engaged in the labor of writing. It examines the authorial imagination in London's work, the use of imagination in both his fiction and nonfiction, and the ways he defined imagination in the creative process in his business dealings with his publishers, editors, and agents. In this first volume of a two-volume biography, Williams traverses the years 1893 to 1902, from London's "Story of a Typhoon" to The People of the Abyss. The Jack London who emerges in the pages of Author Under Sail is a writer whose partnership with publishers, most notably his productive alliance with George Brett of Macmillan, was one of the most formative in American literary history. London pioneered many author models during the heyday of realism and naturalism, blurring the boundaries of these popular genres by focusing on absorption and theatricality and the representation of the seen and unseen. London created an impassioned, sincere, and extremely personal realism unlike that of other American writers of the time. Author Under Sail is a literary tour de force that reveals the full range of London as writer, creative citizen, and entrepreneur at the same time it sheds light on the maverick side of machine-age literature.Description based on publisher supplied metadata and other sources.Electronic reproduction. Ann Arbor, Michigan : ProQuest Ebook Central, YYYY. Available via World Wide Web. Access may be limited to ProQuest Ebook Central affiliated libraries
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