1,721,078 research outputs found
CHARACTERIZATION OF THE CAROTENOID AND CHLOROPHYLL PIGMENTS IN MONOVARIETAL VIRGIN OLIVE OILS FROM VARIOUS ITALIAN OLIVE VARIETIES
No full textThis work presents the investigation of the chlorophyll and carotenoid pigments composition in
monovarietal virgin olive oils produced from the five main olive varieties (Minuta, Ottobratica,
Calabrese, Ogliarola, Baddarica) cultivated in Sicily (south Italy), from four main olive varieties
(Dolce Agogia, Moraiolo, Leccino, Frantoio) cultivated in Umbria (middle Italy), and from three main
olive varieties (Leccino, Oliva Nera di Collecorto, Noccioluta) cultivated in Molise (middle Italy).
Reversed-phase high performance liquid chromatography using a C-30 column with photodiode
array detection was used for pigments analyses. In all, 19 compounds were identified and
quantified in 60 olive oils samples. The qualitative pigments pattern was similar among the
varieties investigated, whereas quantitative differences were found among the different cultivars;
among the varieties investigated in this work, the oils from Umbria showed the highest pigment
content (34.19 ppm in average), followed by the oils from Molise (18.61 ppm in average) and the
oils from Sicily which showed the lowest pigment contents (13.38 ppm in average). In general,
pheophytin (a) was the major component (range 0.49 – 19.42 ppm), followed by -carotene (range
1.27 – 9.30 ppm) and lutein (range 0.44 – 5.12 ppm). Those differences may be due to genetic
factors and/or geographical differences. Moreover, auroxanthin was detected for the first time in
olive oils and was detected only in olive oils from Umbria and Molise regions. The ratio between
the two isochromic pigment fractions, namely the ratio between the chlorophyll and carotenoid
fractions showed an average value close to unity. The lutein/-carotene ratio was less than one in
the majority of the cases. These parameters, along with other analytical parameters, could be
used as indicators of typicality in olive oils. The presence of a specific pigment profile in olive oils
could infact be used to guarantee the genuineness of the product, since the quality control of food
requires a precise knowledge of the pigments composition of the original products
Valorization of raw materials from agricultural industry for astaxanthin and beta-carotene production by Xanthophyllomyces dendrorhous
No full textWaste deriving from food and agro-industries is a growing problem in
our modern society. In order to reduce food waste and its associated
impacts over the environment and public health, innovative strategies
for the conversion of food wastes in added value products are
studied. Whey is one of the prominent waste deriving from Sicilian
diary industry. The growth and the carotenoid biosynthesis of the
yeast Xanthophyllomyces dendrorhous by its cultivation in pre-treated
whey were studied. The study showed the possibility of increasing the
astaxanthin productivity from X. dendrorhous in a batch fermentative
process under continuous illumination. Our work is focused on the
importance of carotenogenesis by X. dendrorhous on whey for the
economic and ecological aspect. The results obtained in the study
provide useful information about the possible use of this waste
material for carotenogenesis from X. dendrorhous
Statistical analysis on Sicilian olive oils
No full textA robust multivariate statistical procedure applied to an accurate gas chromatography (GC) analysis was used to analyze 1004 monovarietal and multivarietal Sicilian extra virgin olive oils coming from 22 cultivars of different geographical areas of Sicily and collected in nine years (1993, 1995, 1996, 1997, 1998, 1999, 2000, 2001 and 2002). The effect of the cultivar, of pedoclimatic conditions as well as of the year of harvesting on the olive oil fatty acid composition and therefore on their classification was investigated. Oleic, linoleic and palmitic fatty acids, important for the nutritional properties of an olive oil, showed a crucial rule in the characterization of olive oil
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
New lignans from Cedrela odorata L. stem bark
Full text linkIntroduction
Cedrela odorata L., a plant member of the Meliaceae family, is a timber tree native to tropical regions of America, also introduced as a cultivated species in Africa and many tropical countries of Asia and Oceania. The infusion of C. odorata stem bark is used in South American folk medicine for the treatment of fever, hemorrhage, inflammation, and digestive diseases, including diarrhea, vomiting, and indigestion. The decoction of the bark is also used in Africa as a remedy for malaria and fever1. Meliaceae plants, particularly species of Cedrela genus, are distinguished by the occurrence of limonoids, alkaloids, and polyphenols such as lignans and proantocianydins2,3. Limonoids has been suggested to be the main responsible of C. odorata pest resistence, however, other biological studies have shown that polyphenols contained in several parts of the plant can have detrimental effects on insects4. This consideration prompted us to investigate C. odorata stem bark polar extracts.
Method
The dried and powdered C. odorata stem bark (300 g), collected in Merida, Venezuela, was sequentially extracted with n-hexane, CHCl3, CHCl3-MeOH (9:1), and MeOH. The CHCl3-MeOH extract was subjected to silica gel chromatography, using CHCl3 and increasing concentrations of MeOH in CHCl3 (0-100%) as eluents, while the MeOH extract was separated on Sephadex LH-20 column eluting with MeOH as eluent. Subsequently, the fractions obtained from both silica gel and Sephadex LH-20 column chromatographies were submitted to RP-HPLC.
Results / Discussion / Conclusion
The phytochemical study of C. odorata stem bark polar extracts led to the isolation of eight compounds including two new lignans (1–2) (Fig. 1), which structures are shown in Fig.1, and six known substances that were characterized as 4,5-dihydroblumenol A (3), 7-megastigmene-3α,6,9-triol (4), catechin (5), scopoletin (6), homovanillic alcohol (7), and 2-(3,4-dimethoxyphenyl)ethyl-O-β-D-glucopyranoside (8). The structural determination of the isolated secondary metabolites was performed by 1D- and 2D-NMR spectroscopic techniques, and by mass spectrometry analyses. All compounds obtained from this species are in accordance with the ones found in other Meliaceae plants.
Bibliographic References
1. Kipassa NT, Iwagawa T, Okamura H, Doe M, Morimoto Y, Nakatani M (2008). Phytochemistry 69: 1782-1787.
2. Pérez-Flores J, Eigenbrode SD, Hilje-Quiroz L (2012). Am J Plant Sci 3: 988-994.
3. Chatterjee AT, Chakraborthy T, Chandrasekharan S (1971). Phytochemistry 10: 2533-2535.
4. Newton AC, Watt AD, López F, Cornelius JF, Mesén JF, Corea EA (1999). Agr Forest Entomol 1: 11-18
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
Dispelling 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
Oleic acid is not the only relevant mono-unsaturated fatty ester in olive oil
Full text link(1) Background: Extra-virgin olive oil (EVOO) is a precious and universally studied food matrix. Recently, the quantitative chemical composition was investigated by an innovative processing method for the nuclear magnetic resonance (NMR) experiments called Multi-Assignment Recovered Analysis (MARA)-NMR. (2) Methods: Any EVOO 13-carbon NMR (13C-NMR) profile displayed inconsistent signals. This mismatch was resolved by comparing NMR data to the official gas-chromatographic flame ionization detection (GC-FID) experiments: the analyses concerned many EVOOs but also the “exotic” Capparis spinosa oil (CSO). (3) Results: NMR and GC-FID evidenced the overwhelming presence of cis-vaccenic esters in the CSO and, more importantly, cis-vaccenic 13C-NMR resonances unequivocally matched the misunderstood 13C-NMR signals of EVOOs. The updated assignment revealed the unexpected relevant presence of cis-vaccenic ester (around 3%) in EVOOs; it was neglected, so far, because routine and official GC-FID profiles did not resolve oleic and cis-vaccenic signals leading to the total quantification of both monounsaturated fatty esters. (4) Conclusions: The rebuilt MARA-NMR and GC-FID interpretations consistently show a meaningful presence of cis-vaccenic esters in EVOOs, whose content could be a discrimination factor featuring specific cultivar or geographical origin. The study paves the way toward new quantification panels and scientific research concerning vegetable oils
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