1,721,087 research outputs found
High-value Metabolites from Hypericum perforatum: a comparison between the plant and in vitro systems
No full textCold pressed grape seed oils: a study on their phenolic content by HPLC/DAD/MS and HPLC/MS/MS
No full textSince the 50s of last century, the production of oil extracted from seeds and oleaginous fruits has increased significantly becoming of great importance in the agricultural worldwide economy. The increased demand has resulted in a significant expansion of the area under oilseed crops. The edible oils are commonly classified into oils extracted from fruit and from oilseeds. This latter group include byproducts of industrial processes as the grape seed from wine industry. In Italy almost all the oilseeds are usually extracted with hexane and commercialized only as refined oils. The refining processes that apply high temperatures induce almost a total disappearance of the phenolic compounds from the oil as also confirmed by a screening on different samples before and after these treatments1. Nevertheless, in several countries of South America, mainly Argentina and Chile the cold-pressed grape seed oil is widely used for human consumption; its pleasant and characteristic taste make it suitable, as for olive oils, to be consumed as crude condiment to flavor dishes. To date, scant data are available on the content of minor polar compounds in these unrefined oils2. Aim of this work was to investigate on the phenolic fraction of two cold pressed grape seed oils from different provenience. The oils were extracted with ethanol/acidic water 7/3 to recover lignans and other more simple phenols. The alcoholic extracts were then analysed on reverse phase by HPLC/DAD/MS on reverse phase and by targeted MS/MS experiments operating in negative ionization mode. The presence of lignans, in particular pinoresinol and one isobar was confirmed in both these oil in comparable amounts to those found in a commercial olive oil (close to 5 mg/L). Some hydroxycinnamic acids and flavonols such as kaempferol and its derivatives were identified by the help of their spectra. Moreover, the MS/MS experiments allowed to identify two ethyl esters of p-coumaric acid and p-methoxy cinnamic acid not identified to date in grape seed oil.
These preliminary data suggest future investigations on a wide number of samples to define the phenolic profiles, to evaluate the antioxidant capacity and the health benefits of the cold pressed grape seed oil
Biosintesi di stilbeni in calli di Vitis vinifera cv Alphonse Lavallée e Malvasia trattati con elicitori biotici.
No full textOlive-oil Phenolics and Health: Potential Biological Properties
No full textExtra virgin olive oil, the primary source of oil in the Mediterranean diet, differs significantly in composition from dietary lipids that are consumed by other populations. The several minor constituents of virgin olive oil include vitamins such as alpha- and gamma-tocopherols (around 200 ppm) and beta-carotene, phytosterols, pigments, terpenic acids, flavonoids, squalene, and a number of phenolic compounds, such as hydroxytyrosol, usually grouped under the rubric "polyphenols". The antioxidant and enzyme-modulating activities of extra virgin olive oil phenolics, such as their ability to inhibit NF-kappa B activation in human monocyte/macrophages has been demonstrated in vitro. There is also solid evidence that extra virgin olive oil phenolic compounds are absorbed and their human metabolism has been elucidated. Several activities that might be associated with cardiovascular protection, Such as inhibition of platelet aggregation and reduction of plasma rHcy have been demonstrated in vivo. The biologically relevant properties of olive phenolics are described, although further investigations in controlled clinical trials are needed to support the hypothesis that virgin olive oil consumption may contribute to lower cardiovascular mortality
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
Inactivation of Herpes Simplex Virus type 1 and inhibition of cell-to-cell diffusion by chicoric acid extract.
No full textClustering Monovarietal Extra Virgin Olive Oil According to Sensory Profile, Volatile Compounds, and k-Mean Algorithm
Full text linkA real valorization of monovarietal extra virgin olive oils (EVOOs) through diverse sensory profiles is missing, hindering different uses of samples with different sensory profiles and leading to negative impacts on EVOO competitions and consumer choices. The aim of this research is to group monovarietal EVOOs according to similar sensory and chemical profiles. The volatile and phenolic composition and the sensory profile of 46 monovarietal EVOOs are analyzed by head space-solid phase micro extraction-gas chromatography-mass spectrometry, HPLC-DAD, and Panel Test; the data are used to feed a k-mean algorithm aimed at samples clustering. A group of non-monovarietal samples is also included. It is hypothesized that samples of a cultivar are located in a cluster, while non-monovarietal samples are randomly located in different clusters. Two clusters of samples are identified; all samples belonging to a specific cultivar are in the same cluster and the non-monovarietal ones randomly placed in the two clusters. The significant attributes in differentiating between the two clusters belong to sensory descriptors and volatile compounds; phenolic compounds do not give significant differentiation. All sensory descriptors result in prevalence in one cluster. The two clusters are differentiated by volatile organic compounds (VOCs) originating by different branches of the lipoxygenase-pathway. Practical Applications: The results of this research will help toward a real valorization of extra virgin olive oils (EVOOs), and particularly, the monovarietal ones. In this sense, the results clearly suggest the use of an adequate profile sheet for the definition of the sensory profile of monovarietal EVOOs. By this way, during EVOO competitions, samples with a certain type of sensory profile will compete against samples with the same type of sensory profile, just as it happens for other types of products
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