1,721,100 research outputs found
Pro-oxidant action of polar triglyceride oligopolymers in edible vegetable oils
No full textThe aim of the research was to evaluate the pro-oxidant action of oxidized triglyceride oliogopolymers, a class of oxidation compounds present in refined vegetable oils. Silica gel column chromatography was used to obtain the polar compounds from a thermally oxidized oil and preparative gel permeation chromatography to separate and collect the oxidized triglyceride oligopolymers. A purified oil that was practically free of oxidation and hydrolytic degradation products, pigments and anti-oxidants was prepared in the laboratory to evaluate pro-oxidant activity without interferences. Addition of percent amounts of oxidized triglyceride oligopolymers of 0.25 to 1.0% to both the purified and unpurified oils clearly evidenced the pro-oxidant activity of this class of compounds. © 2007 Springer-Verlag
Composti di ossidazione e polimerizzazione di trigliceridi durante la raffinazione di oli vegetali alimentari
No full textAnthracyclines as Topoisomerase II Poisons: From Early Studies to New Perspectives
Full text linkMammalian DNA topoisomerases II are targets of anticancer anthracyclines that act by stabilizing enzyme-DNA complexes wherein DNA strands are cut and covalently linked to the protein. This molecular mechanism is the molecular basis of anthracycline anticancer activity as well as the toxic effects such as cardiomyopathy and induction of secondary cancers. Even though anthracyclines have been used in the clinic for more than 50 years for solid and blood cancers, the search of breakthrough analogs has substantially failed. The recent developments of personalized medicine, availability of individual genomic information, and immune therapy are expected to change significantly human cancer therapy. Here, we discuss the knowledge of anthracyclines as Topoisomerase II poisons, their molecular and cellular effects and toxicity along with current efforts to improve the therapeutic index. Then, we discuss the contribution of the immune system in the anticancer activity of anthracyclines, and the need to increase our knowledge of molecular mechanisms connecting the drug targets to the immune stimulatory pathways in cancer cells. We propose that the complete definition of the molecular interaction of anthracyclines with the immune system may open up more effective and safer ways to treat patients with these drugs
Qualitative and quantitative characterisation of the lipid fraction of bouillon cubes
No full textAn experimental investigation was performed
to characterise the fat fraction of bouillon cubes. Besides
the routine analyses, the analytical methods used were:
silica-gel column chromatography to separate polar compounds,
high performance size-exclusion chromatography
(HPSEC) for the qualitative and quantitative determination
of the single classes of substances constituting
the polar compounds, and gas chromatography to determine
the acid composition and the trans isomers of unsaturated
fatty acids. The fats blended into the bouillon
preparations were highly variable and were mainly made
up of refined vegetable oils that had undergone hardening,
by hydrogenation in most cases. Determination of
the free fatty acids and of the peroxide values yielded
figures that in some cases exceeded the limits set for the
commercialisation of refined vegetable oils. Compared
to the routine analyses, the HPSEC analysis of the polar
compounds provided a better evaluation of the level of
degradation of the fat extracted from the bouillon formulations.
The levels of oxidative and hydrolytic degradation
were rather high, and similar to those reported for
poor quality oils. Analyses of the trans isomers of oleic
acid yielded particularly high values (even over 20%)
and differentiated the cubes on the basis of the type of
fat added
Fate of oxidized triglycerides during refining of seed oils
No full textThe evolution of oxidized triglycerides (ox-TG) during industrial refining was studied in soybean,
sunflower, peanut, and corn oils. The analytical techniques used were silica gel column chromatography
and high-performance size exclusion chromatography. The decrease in ox-TG during refining
(42.3% on average) was accompanied by an increase in triglyceride oligopolymers (TGP). The inverse
correlation between the two lipid groups suggests that the decrease in ox-TG during refining was
due in part to the occurrence of polymerization reactions. An inverse correlation was also found
between the percentage sum of ox-TG + TGP and percent TGP, indicating that a part of the ox-TG
also underwent degradation or transformation reactions. On average, almost 58% of the ox-TG
remained unchanged during refining and, of the rest, about half was involved in polymerization reactions and half in degradation or transformation reactions
Non conventional parameters for quality evaluation of refined oils with special reference to commercial class olive oil
No full textForty olive oil samples (refined olive oil plus virgin olive oil) were tested to check the possibility of using recent non-conventional
analytical parameters to assess quality. The routine analyses prescribed by the EEC Reg. No 2568/91 and subsequent extensions
were carried out on all samples. The analytical techniques used included silica gel column chromatography for the separation of
polar compounds from oil, and their subsequent high performance size-exclusion chromatography (HPSEC) analysis to quantify
the oxidation, polymerisation and hydrolysis product classes. Based on the results obtained, it seems logical to use the percent oligopolymer
content to measure the level of oxidation in commercial class olive oil. The diglyceride level can provide information
about the extent of hydrolytic degradation
Comparative study and quality evaluation of Italian focaccias seasoned with extra virgin olive oil
No full textAn extra virgin olive oil was used as seasoning for three different types of focaccia produced on an industrial scale. This oil and samples of the oil extracted from the focaccias after baking were submitted to routine analyses and to silica gel column chromatography to separate polar compounds. These were then subjected to high performance size-exclusion chromatographic (HPSEC) analysis and it allowed to determine oxidative and hydrolytic degradation products. The results were compared with those obtained from artisan focaccias, seasoned with the same oil and toppings, by statistical analyses. The different technologies and the toppings employed directed in different ways the oxidative and hydrolytic processes in the oil. Copyright © Taylor & Francis Group, LLC
Quality of the lipid fraction of Italian biscuits
No full textAlthough not perceived as fatty foods by consumers, biscuits contain a consistent quantity of lipids. Since they are daily present in the diet, an experimental study was carried out with the aim of evaluating the quality of the lipid fraction of biscuits. Amounts of fat ranging from 75 to 231 g kg(-1), mainly constituted by refined vegetable oils and margarine, were present. A high variability in fatty acid composition was found and in some cases high amounts of trans isomers of unsaturated fatty acid were observed. In addition, HPSEC analysis of polar compounds indicated an extensive hydrolytic degradation of triacylglycerols and also a high level of oxidative degradation. The latter, demonstrated by means of the contemporary measure of oxidised triacylglycerols and of triacylglycerol oligopolymers, was comparable to that found in hydrogenated oils and fats
Changes in the oxidative state of extravirgin olive oil used in baked Italian focaccia topped with different ingredients
No full textFour different types of "focaccia" (Italian flat bread) prepared with the same dough and the same extra virgin olive oil but with different seasonings, were analyzed. Lipids were extracted from each sample using the Folch method. The indices commonly used to assess oil quality, the amounts of trans fatty acids and compounds of triglyceride polymerization, oxidation and hydrolysis, were determined in all the samples to better assess the degree of oxidation and hydrolysis of the oils. The findings showed that, once baked, the oil sampled from the different types of focaccias could not be included in the virgin category. The level of oxidation of the baked samples was greater than that in the uncooked oil. However the results obtained showed that the level of degradation of the extracted oils was lower than that found in edible refined oils and it seemed to be influenced by the topping used to flavour the focaccias. © 2007 Elsevier Ltd. All rights reserved
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