1,720,962 research outputs found
Effect of moisture content on the extraction rate of coffee oil from spent coffee grounds using Norflurane as solvent
No full textRecently, vegetable oils have been widely used in several industrial fields as food additives, biofuels, cosmetic ingredients, packaging materials, or pharmaceutical compounds. In this study, we investigated the extraction of lipids from spent coffee grounds using an innovative system and the hydrofluorocarbon Norflurane, as solvent. Extraction experiments were performed on matrices at different levels of moisture under a recirculating solvent flow in the pressure range 5−11 bar. The results confirmed the effectiveness of the novel extraction process on wet, dried and partially dried matrices, and the oil yields and the extraction times (approximately 92% in 75, 90 and 285 min respectively) were comparable with those obtained using the more expensive supercritical CO2 process. A kinetic approach was used to model the extraction rates of wet, dry and partially dried samples. It showed that a partial drying of the SCG promoted the solubilization of oil in Norflurane during the first extraction stage and improved the contact between Norflurane and the oily solute. The fatty acid profiles of the extracts were determined and the results revealed the presence of palmitic (C 16:0) and linoleic (C 18:2) acids, as major components, and stearic (C 18:0) and oleic (C 18:1) acids, as minor components
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
Nitration of cinnamic acids using cerium (IV) ammonium nitrate immobilized on silica
No full textTreatment of cinnamic acids with cerium (IV) ammonium nitrate supported on silica (CAN/SiO2) was used to synthesize nitro derivative and ipso substitution products. The position of the substituents defines the type and the yields of the products. This is the first example of an ipso substitution reaction by solid-phase approach
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
Innovative solid-liquid extractor for hop
No full textHop is a basic raw material used in beer brewing. To standardize the hop prodn. process and to improve its storage stability, hop is produced in the form of pellets by extn. with ethanol or supercrit. CO2. Hop exts. obtained with supercrit. CO2 (with or without ethanol co-eluent) and the Naviglio solid-liq. extractor were compared using capillary electrophoresis anal. The Naviglio extractor was superior to compared supercrit. CO2 technique in terms of ext. α- and β-bitter acid contents
Recovery of Carotenoids from Tomato Pomace Using a Hydrofluorocarbon Solvent in Sub-Critical Conditions
No full textThe enrichment of oils with nutraceutical bioactive phytomolecules allows the achievement of functional oil-based products of great interest in the food, pharmaceutical, and cosmetic fields. Carotenoids, such as lycopene and β-carotene, are available at a high concentration in tomatoes and tomato waste products, as peels, seeds, and pulp; their recovery is recently attracting growing interest and economic importance in the food industry, and also in consideration of the huge amount of industrial waste produced. The aim of this work is to study the production of an oil functionalized with carotenoids from tomato peels. The extractions were carried out using an innovative process based on the use of commercial Norflurane as solvent in subcritical conditions. Extraction trials were performed on dried tomato peels, with the addition of tomato seeds or wheat germ flour as sources of oily co-solvents, capable of also preserving the biological characteristics of the carotenoids extracted. Although lycopene solubility in Norflurane is quite low, the solvent recirculation and regeneration were allowed to reach a concentration in the oily extracts of approximately 0.3 mg/goil after 2 h of the process. The enrichment in β-carotene was more pronounced, and concentrations of 0.733 mg/goil and 0.952 mg/goil were observed in wheat germ and tomato seed oils, respectively. The results obtained in this study were compared with those obtained by traditional and supercritical CO2 extraction methods
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
Extracting the lipid fraction from waste bilberry seeds with a hydrofluorocarbon solvent
No full textThe consumption of vegetable oils has increased in recent years due to their nutraceutical properties. There is growing scientific research interest in the development of innovative, efficient and sustainable extraction techniques capable of separating lipid fractions from vegetal matrices. In this study, we introduce an innovative technique for extracting lipids from bilberry seeds that uses Norflurane, a hydrofluorocarbon, as the solvent under subcritical conditions. Preliminary extraction experiments were carried out using bilberry seeds in the waste material from the bilberry drupe valorization process. Different granulometric bilberry fractions were selected, suitably crushed, and sized prior to extraction. An extraction efficiency of 91% of the total lipid content was obtained for the ground fraction with grains 450−710 μm in size. The main fatty acids present in the lipid extracts were oleic, linoleic and α-linolenic acids. The ratio of unsaturated-to-saturated fatty acids was determined to be 11.63, with a ω6/ω3 ratio of 1.06
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