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Recenti acquisizioni analitiche per la valutazione della qualità, genuinità e stabilità dei grassi alimentari
No full textA 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
Applicazione della estrazione in fase solida (SPE) alla determinazione dei diacilgliceroli negli alimenti
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ANTIOSSIDANTI DA PIANTE OFFICINALI, SALVIA ED ORIGANO: COMPOSIZIONE DELLA FRAZIONE FENOLICA ED ATTIVITA' ANTIOSSIDANTE
No full textAnalysis of virgin olive oil volatile compounds by head space solid phase microextraction coupled to gas chromatography with mass spectrometric and flame ionization detection
No full texthe efficiency of headspace solid-phase microextraction (SPME) was evaluated for the qualitative and semi-quantitative analysis of virgin olive oil volatile compounds. The behaviour of four fibre coatings was compared for sensitivity, repeatability and linearity of response. A divinylbenzene-Carboxen-polydimethylsiloxane fibre coating was found to be the most suitable for the analysis of virgin olive oil volatiles. Sampling and chromatographic conditions were examined and the SPME method, coupled to GC with MS and flame ionization detection, was applied to virgin olive oil samples. More than 100 compounds were isolated and characterised. The presence of some of these compounds in virgin olive oil has not previously been reported. The main volatile compounds present in the oil samples were determined quantitatively
Valutazione della frazione volatile del prosciutto crudo San Daniele mediante analisi SPME-GC-MS
No full textEvaluation of volatile compounds in “San Daniele” dry cured ham , by SPME-GC-MS analysis
In this work, the volatile fraction of “San Daniele” dry raw ham was studied using the SPME-GC-MS technique. The method used has
permitted to detect over one hundred compounds present in the head space of the samples. Due to the chosen conditions, for most of
the detected compounds good repeatibilty values have been obtained. The most prevalent classes of compounds were those of the
alcohols and aldehydes. Moreover, the samples have revealed a broad variability of compositio
Solid-phase microextraction in the analysis of virgin olive oil volatile fraction: modifications induced by oxidation and suitable markers of oxidative status
No full textModifications of virgin olive oil subjected to accelerated storage were evaluated by HS-SPME analysis.
To find a suitable marker of oxidative degradation, the volatile compounds showing variable
concentration during the oxidative process have been identified and quantified by SPME coupled to
GC-MS and GC-FID, respectively. The SPME analysis results were then compared with the
parameters usually applied to assess the oxidative status of lipids, such as peroxide value,
spectrophotometric absorbance, and loss of unsaturated fatty acids. Finally, the assessment of nonanal
has been suggested as a marker of oxidative degradation. This rapid, inexpensive, and reliable method
may allow screening of oils prior to testing by a panel of assessors
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