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An 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.

Four 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.

Olives (Olea europaea cv. Coratina) used for oil production were stored for 30 days at three different temperatures and under different atmospheres (ambient temperature, 5 °C with a flux of humidified air, 5 °C with a flux of 3%O2 + 5%CO2). The olives were kept in jars used for fruit storage, each with a capacity for 1.5 kg of olives. Conventional analyses (acidity, peroxide value, specific extinction coefficient at 232 nm and 270 nm) and non conventional (polar compounds) analyses were carried out in order to measure the hydrolytic and oxidative degradation of the oils obtained from the olives. Storage at 5 °C, both under a flow of humidified air and a flow of 3%O2 + 5%CO2, produced oils that maintained their initial chemical qualities until the end of the experimentation; whereas storage of olives at room temperature led to their deterioration after 15 days of storage.

Although 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 231gkg −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.  2005 Society of Chemical Industry

Forty 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.

The 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.

Three major virgin olive oil varieties (Dritta, Leccino, and Coratina) extracted by a modern centrifugation system aided with a new plant enzyme preparation (having prevalently pectolytic activity) were characterized. These oils showed a clearly enhanced quality standard, owing to higher levels of some important minor components (phenolics, volatiles, tocopherols, carotenes, and chlorophylls) and to frequently lower concentrations of oxidized triglycerides and diglycerides. The oils were therefore characterized by lower susceptibility to oxidation and longer shelf life, and their flavor, aroma, and color features appeared to be significantly improved. The saponifiable fraction was practically not affected as the enzymatic effects involved only the membranes of the oil droplets, where the nonglyceridic compounds are essentially located.

An 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.

An experimental investigation was carried out with the aim to evaluate the pro-oxidant activity of oxidized triacylglycerols and compare it with that observed for polar triacylglycerol oligopolymers. The research on these classes of substances, that form during processing and storage of fats and oils, has a great concern with the study of the effect of heat in technologic processes, such as vegetable oils refining, frying and cooking. Oxidized triacylglycerols and polar triacylglycerol oligopolymers, obtained in purity by preparative gel permeation chromatography, were added in amounts of 0.25-1 g/100 g both to a purified and an unpurified olive oil. Regarding the oxidized triacylglycerols, the accelerated oxidation tests showed that the induction times of both oils significantly decreased at increasing concentrations of these compounds, demonstrating their pro-oxidant effect. Moreover, the data showed that the pro-oxidant activity of oxidized triacylglycerols was greater than that of polar triacylglycerol oligopolymers. © 2010 Elsevier Ltd.

The fatty substances used in bakery products vary a lot in nature and content. The most largely used lipids are butter, lard, hydrogenated vegetable oils, margarines, olive oil and olive-pomace oil; their content may range from 5 to 15% for some bread substitutes, such as focaccia, rusks, crackers, breadsticks, and up to 20-30% in the case of pastry products, such as biscuits and cakes. The choice of the most suitable kind of lipid and the optimal amount needed in the formulation is closely related to the desired bakery product, and is based on different parameters such as the dough workability, the product's rheological and sensory properties, the shelf-life and the consumers' needs. During the first processing step the "lipid binding" starts up: chemical and physical interactions are established between the lipids and other ingredients, such as starch and proteins (gluten). This process also involves free endogenous lipids (naturally contained in flours), i.e., lipids not chemically bound to cell structures or to other meal components. The formation of gliadine-lipid-glutenine complexes allows the dough to incorporate the gases, which develop during fermentation, and to retain them in the gluten mesh, thus giving volume and softness to the leavened product. © 2010 Copyright © 2010 Elsevier Inc. All rights reserved.

The 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.