1,720,991 research outputs found
Valorization of agro-industrial fermentation residues: biotransformation of ginger active molecules
No full textThe ginger rhizome is a primary ingredient of oriental food, beverage, and herbal medicine catching on Western Countries meals. In 2016 the food sector processed 3.3 million tonnes of ginger generating a pulp waste that was mostly destined to agricultural field, biorefinery, papermaking etc.1 The ginger pulp waste still contains an oleoresin rich in gingerol-like compounds, such as gingerols and shogaols, bioactive components with recognized anti-inflammatory and anticancer properties.2,3
As an alternative valorisation strategy, the recovery of the main ginger waste components and their biotransformation to generate a small library of optically enriched derivatives was herein investigated. The oleoresin was first extracted from a fermented ginger biomass originating from a local farm. The conventional extraction confirmed the presence of still 30% gingerol-like compounds with unaltered chemical profile as characterized and quantified by UPLC-TUV and GC-MS. Then the enantioselective reduction of prochiral carbonyl moiety of pure isolated 6-gingerol (1), 8-gingerol (2), 6-shogaol (3), 8-shogaol (4), 6-paradol (5), 8-paradol (6) and zingerone (7) by different alcohol dehydrogenases (ADHs)4 was investigated. From our preliminary results, no ketone reduction was observed for 3 and 4. As far as the other substrates concern, only the ADH from Micrococcus luteus and engineered ADHs from Evoxx led to chiral alcohols in low yield, but with good diastereo- and enantiomeric excess (d.e and e.e) (Figure 1)
Silverskin: from waste to a renewable source of bioactive compounds
No full textSilverskin is the thin layer covering the coffee beans. During the roasting coffee process, it is removed becoming a by-product. The large production (150.000 t/year on global scale, of which 7.500 t/years in Italy) of this waste calls for its re-functionalization in order to reduce the impact of industrial by-products in the environment. Currently the only use of coffee silverskin (CS) is as renewable energy source or as fertilizer (1,2), no other utilization has been developed for CS so far. Despite this, the chemical composition of CS indicates the presence of interesting bioactive molecules (i.e. lipids, chlorogenics acids, caffeine) that confer to this by-product antioxidant and prebiotic properties. (3)This evidence suggests its re-use as well in other industrial fields such as nutraceutical, cosmetic and pharmaceutical as aimed by CirCO project. In this hypothesis of revalorization, it cannot be excluded the potential use of CS lipid matter in cosmetic formulations or as additive for the technology of paper processing (4). For the isolation of CS oil, supercritical CO2 was selected as more sustainable separation technique, alternative to classical solvent extraction processes.(5) We observed that an appropriate modulation of process parameters (T, P) influence the oil rate and the chemical composition opening the way for targeted extraction. In details the application of mild conditions (35°C, 100/200psi) led to majority extraction of palmitic (C16:0) and linoleic (C18:2) acids with an overall yield of 1.9% (goil/100gCS). The increase of pressure (100 bar300 bar) and temperature (35°C60°C) promoted the extraction of arachidic acid (C20:0), behenic acid (C22:0) and lignoceric acid (C24:0) with a calculated oil yield of 3.3% (goil/100gCS). The best identified conditions were employed for the industrial scale-up giving results comparable to laboratory scale. For a possible commercial process application, it is essential to test the applicability of appropriate models for SFE of lipids from oil-containing substrates.(5) For this purpose a mathematical model is constructed based on the experimental data collected, employed apparatus and chemical-physical characteristic of biomass in tightly collaboration with prof. Manenti at Politecnico of Milan
Supercritical CO2 extraction of polyphenols from agri-food residues
No full textIntroduction Environmental concerns arising from the use of organic solvents in extraction procedures might be overcome by an innovative technology: supercritical CO2 (scCO2). It enables the extraction of compounds soluble in scCO2, perfectly applicable to lipophilic molecules (1). The addition of a co-solvent is able to modify the polarity of the fluid allowing the extraction of more polar molecules (2). Despite these advantages, very few applications to extract polar compounds have so far been reported. Material & Methods Sea urchin wastes, pomegranate fermentation byproducts and residues of coffee roasting were loaded in the extraction vessel. scCO2 extractions were performed in the presence of co-solvents (ethanol, methanol, ethylacetate) at different T and p. Results Changes in the operative conditions led to selective extraction of classes of compounds. The procedure was assessed to yield polyhydroxylatednaphtoquinones from sea urchins’ wastes, ellagic acid from pomegranate fermentation wastes (3) and chlorogenic acids from byproducts of coffee-roasting. Conclusions Effects of main operating conditions (temperature: 35-55°C, pressure: 300-400 bar and co-solvent: 5- 20%) have been assessed. The addition of a co-solvent was necessary to enable polyphenols extraction. Yields were lower compared to conventional extractions, however scCO2 provided high-purity extracts, as demonstrated by the enhanced antioxidant activity
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
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Influenza di composti di ossidazione e polimerizzazione di trigliceridi sulla resistenza all’ossidazione di oli vegetali alimentari
No full textDispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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