Stereospecific distribution of fatty acids in triacylglycerols of olive oils

The positional distribution of fatty acids (FA) in triacylglycerols (TAG) of 47\u2009virgin olive oils from diverse cultivars grown in distinct areas of North-Eastern Italy was studied. Few data were previously available on oils from these geographical areas. The effects of climatic and geographical conditions on the stereospecific distribution of TAG in olive oil were confirmed. Moreover, the results of the stereospecific analysis were used to evaluate the preferential esterification position of each FA on the basis of the degree of unsaturation and the chain length. The data of the stereospecific analysis of olive oil TAG can contribute to the determination of the selectivity of olive fruit acyltransferases for distinct FA

Solid-phase microextraction in the analysis of virgin olive oil volatile fraction: characterization of virgin olive oils from two distinct geographical areas of northern Italy

SPME was employed to characterize the volatile profile of virgin olive oils produced in two geographical areas of northern Italy: the region of the Gulf of Trieste and the area near Lake Garda. There are as yet no data on the headspace composition of virgin olive oils from these regions, characterized by particular conditions of growth for Olea europaea. Using the SPME technique coupled to GC-MS and GC-FID, the volatile components of 42 industrially produced virgin olive oil samples were identified and the principal compounds quantitatively analyzed. Significant differences in the proportion of volatile constituents from oils of different varieties and geographical origins were detected. The results suggest that besides the genetic factor, environmental conditions influence the volatile formation

The advancement of the assessment of food quality control as stressed by recent development in analytical chemistry

Several aspects of food quality control (identity and quality) are discussed in this paper. Besides official and traditional methods, which are often time consuming and not always suitable to obtain an adequate description of the analysed food, a number of new methods have been developed within the last few years. The development of analytical methods depends on the development of analytical instrumentation and more accurate knowledge about food composition. Recent trends in food analysis control are to limitate at minimum sample manipulation and to reduce solvent utilisation. Thus, Supercritical Fluid Extraction, Solid Phase and Solid Phase Micro Extraction advantages are discussed, as well as a new analytical approach such as Hyphenated Techniques in Chromatography (LC-GC, LC-LC-GC) applied to trace analysis (PAHs), or volatile compounds stripping and GC-MS analysis applied to honey classification, aided by chemometric methods

Thermal degradation of single 7-cholesteryl acetate hydroproxide

The thermal degradation products of the 7\u3b1- and 7\u3b2-cholesteryl 3\u3b2-acetate hydroperoxides obtained by thermal oxidation of cholesteryl 3\u3b2-acetate are reported and discussed. The hydroperoxides were degraded in both the vapour and condensed phases. The main components identified were 7-ketocholesteryl 3\u3b2-acetate, 7\u3b1- and 7\u3b2-hydroxycholesteryl 3\u3b2-acetates and the products generated from the loss of the hydroperoxide group and/or of acetic acid. Remarkable is the finding of the epoxy-hydroxy derivatives of cholesteryl acetate among the degradation products

Valutazione della attivit\ue0 antiossidante di oli extra vergini di oliva

In order to investigate on the role of antioxidant compounds of olive oil, in this work the content and composition of tocopherols and polyphenols of extra virgin olive oils from Garda, Romagna and Trieste were evaluated. Significative correlations were found between tocopherols content and antioxidant activity evaluated by means of crocin test and between phenolic composition and oxidative stability measured by Rancimat test

Recenti acquisizioni analitiche per la valutazione della qualit\ue0, genuinit\ue0 e stabilit\ue0 dei grassi alimentari

A number of chemical parameters has been proposed and sometimes adopted as time passes, with the aim of assess identity and quality of fatty substances. In this paper, the advancement of knowledges about fatty substances composition is stressed as highlighted by analytical instrumentation developments. Furthermore, a number of acquisition are rewieved, as they become available by hyphenation of analytical instrumentation, as LC-GC, LC-LC and LC-LC-GC. New trends in analytical evaluation of olive oils deal with application of NMR as well as Raman spectroscopy and Near Infrared Reflectance analysis. The main problem of fatty substances is oxidation: a number of recent knowledges are reported, dealing with products of oxidation of sterols, catalysed by heat and light, photo oxidation products and thermo oxidation products of sterols have been studied and identified. This lead to explain the possibility of newly formed sterenes in refined oils: their structure characterised by one more double bond in the rings is in good agreement with the dehydration of oxysterols. The antioxidative properties of a number of natural substances can be studied by means of stressed conditions, as realised in the Rancimat test or in the presence of free radicals at lower temperature, as realised in the crocine test. Xenobiotic, too, can occasionally be present in fatty substances, among these, polycyclic aromatic hydrocarbons have attracted the attention of several researchers since twenty years ago, significative advancement of analytical instrumentation in this field, too, admits their evaluation and study of their occurrence in fatty foods