117,306 research outputs found
On the presence of cholesterol in ham (valutazion de presince di ossits dal colesterul tal persut)
No full textDevelopment of flavour in food, and in meat food is a very complex process,
that involves a number of chemical reactions on lipid and proteins. Lipid oxidation does
not involve fatty acids only, but sterols as well, in meat foods this happens on cholesterol,
mainly.
Cholesterol oxides (COPs) are extensively studied because of their cytotoxic activity
and they are a risk factor for consumers health.
In this paper, COPs were measured in longissimus dorsi, subcutaneous, intramuscular
fat and lean meat volatile compounds of the same samples were also analysed.
Results highlighted the presence of COPs, mainly 7-keto cholesterol: average concentrations
were 0,6 mg/kg in muscle and 0,9 mg/kg in fat. Data are in good agreement
with those already published for other kinds of hams.
The volatile fraction too was analysed on the same samples, and results demonstated
that aldehydes and ketones, were present as in Parma ham, but unlike Spanish ham
Valutazione dell’attività antiossidante di composti fenolici nei fumi per affumicatura.
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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 textFormation of the 5,6-epoxy derivatives of 7-hydroxy-cholesteryl-3β-acetates during peroxidation of cholesteryl acetate
No full textThe thermal peroxidation of cholesteryl acetate (CA) generates many compounds, most of which have been identified in previous studies. The trimethylsilyl (TMS) derivatives of the thermodegradation products of the single hydroperoxides of CA (7 alpha- and 7 beta-) gave GC-MS spectra that were almost identical to those of the thermal peroxidation of CA, except for four compounds that were only detected as TMS derivatives. These substances were identified by comparing their mass spectra and their GC retention time against those of the four synthesized isomers of the epoxy-hydroxy derivatives of CA. The presence of a considerable amount of epoxy-hydroxy derivates of CA, especially at low-temperature degradations, provides an explanation for the formation of other substances that have been previously identified
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