Search results for "010401 analytical chemistry"
showing 10 items of 1284 documents
Isolation and determination of phenolic compounds from freshwater Cladophora glomerata
2020
Abstract Marine algae biomass has gained widespread interest in the world of science and many industries. The growing number of publications proves that these algae are an interesting and essential natural resource. This interest is due to the presence of a variety of biologically active compounds that give algae extracts a broad spectrum of biological and functional properties. However, there is little data on the chemical composition of algae obtained from freshwater. This work focuses on the isolation and determination of phenolic compounds from freshwater algae of the species Cladophora glomerata. Different types of extraction and extractants were used to isolate these bioactive compoun…
Worldwide Scientific Research on Nanotechnology: A Bibliometric Analysis of Tendencies, Funding, and Challenges
2020
[EN] The main objective of this investigation was to analyze the scientific production in global research on nanotechnology, integrating scientific production, funding of studies, collaborations between countries, and the most cited publications. The source for obtaining the research papers for our analysis was the Science Citation Index Expanded from the Web of Science. A total of 3546 documents were extracted during the period of 1997-2018. Food science & technology, chemistry (applied and analytical), spectroscopy, and agriculture appeared as the main areas where the articles were published. Most prolific and cited journals were Analytical Methods, Journal of Agricultural and Food Chemis…
Chromatographic separation and partial identification of glycosidically bound volatile components of fruit
1990
Abstract Synthetic monoterpenic and aromatic β- d -glucosides and β- d -rutinosides were separated by Fractogel TSK HW-40 S chromatography according to their molecular size and interactions occurring between the aglycone moiety and the gel matrix. Under these conditions terpenyl rutinosides were eluted before the homologous glucoside derivatives. In the two classes, monoglucosides and rutinosides, aromatic glycosidically bound components had lower retention times than the corresponding terpenyl components. The use of over-pressure layer chromatography (OPLC) allowed the separation of glucoside and rutinoside derivatives, and in these two classes aromatic and several monoterpene compounds we…
Contamination of fresh and dried tomato by Alternaria toxins in southern Italy.
2019
In the present investigation, fresh and dried tomato samples from markets and packinghouses located in Apulia region (southern Italy) were analysed for Alternaria toxins. All samples proved to be contaminated by tenuazonic acid (TeA); in particular, dried tomatoes were contaminated in the range 425-81,592 µg/kg, while fresh tomatoes were in the range 11-4560 µg/kg. The second most abundant toxin was alternariol monomethyl ether (AME), followed by tentoxin (TEN) and alternariol (AOH). Overall dried tomatoes were more contaminated than fresh ones, although this seemed not directly related to the presence of sodium chloride, utilized in the drying process. Five representative Alternaria isolat…
Novel Wood Resistance Measurement Method Reducing the Initial Transient Instabilities Arising in DC Methods Due to Polarization Effects
2019
A novel method for measuring the electrical resistance in wood is presented. It is based on applying an Alternating Current (AC) to two electrodes rammed into the wood. The method reduces the transient time for value stabilization. In case of Direct Current (DC) resistance measurement methods, typically used in wood measurement, an initial transient exists, invalidating the measured value during an initial transient period. This measurement method uses an electronic circuit based on a relaxation oscillator where the wood automatically sets the oscillation frequency depending on its electrical resistance. Compared to other AC methods, this circuit greatly simplifies the measurement process, …
Grafting affects yield and phenolic profile of Solanum melongena L. landraces
2016
Abstract The influence of grafting on agronomical and qualitative characteristics of four Sicilian eggplant landraces was investigated. Grafted and ungrafted plants were compared in the open field in the northern coast of Sicily. Solanum torvum seedlings were used as rootstock. Regardless of genotypes tested, grafting significantly increased total fruit production, marketable production, and number of marketable fruits, but did not affect weight of marketable fruits and waste production. Landrace 2 (Sciacca), with black epidermal tissue and pyriform fruit shape, when grafted onto S. torvum not only gave a higher yield performance than ungrafted plants, but also showed a higher phenolic anti…
Impact of Nitrogen Addition on Wine Fermentation by S. cerevisiae Strains with Different Nitrogen Requirements
2021
In modern oenology, supplementation of nitrogen sources is an important strategy to prevent sluggish or stuck fermentation. The present study thoroughly determined the effect of nitrogen addition timing and nitrogen source type on fermentation kinetics and aroma production, carried out by yeast strains with low and high nitrogen requirements. The results revealed that yeast strains with different nitrogen requirements have divergent reactions to nitrogen addition. Nitrogen addition clearly shortened the fermentation duration, especially for the high-nitrogen-demanding yeast strain. Nitrogen addition at 1/3 fermentation was the most effective in terms of fermentation activity, nitrogen assim…
Identification of New Odorous Heterocyclic Compounds in French Blue Cheeses
2000
International audience
Inhibitory Effect of Azamacrocyclic Ligands on Polyphenol Oxidase in Model and Food Systems
2020
[EN] Enzymatic browning is one of the main problems faced by the food industry due to the enzyme polyphenol oxidase (PPO) provoking an undesirable color change in the presence of oxygen. Here, we report the evaluation of 10 different azamacrocyclic compounds with diverse morphologies as potential inhibitors against the activity of PPO, both in model and real systems. An initial screening of 10 ligands shows that all azamacrocyclic compounds inhibit to some extent the enzymatic browning, but the molecular structure plays a crucial role on the power of inhibition. Kinetic studies of the most active ligand (L2) reveal a S-parabolic I-parabolic noncompetitive inhibition mechanism and a remarkab…
Hydrogen isotopes reveal evidence of migration of Miniopterus schreibersii in Europe
2020
Abstract Background The Schreiber’s bat, Miniopterus schreibersii, is adapted to long-distance flight, yet long distance movements have only been recorded sporadically using capture-mark-recapture. In this study, we used the hydrogen isotopic composition of 208 wing and 335 fur specimens from across the species' European range to test the hypothesis that the species migrates over long distances. Results After obtaining the hydrogen isotopic composition (δ2H) of each sample, we performed geographic assignment tests by comparing the δ2H of samples with the δ2H of sampling sites. We found that 95 bats out of 325 showed evidence of long-distance movement, based on the analysis of either fur or …