1,720,986 research outputs found
Identificazione delle sostanze maleodoranti nelle alterazioni ossidativa e putrefattiva di insaccati crudi stagionati
No full textThe organic volatile compounds produced in oxidized and maleodorous dry salami have been identified. They are: a) in oxidized dry salami: heptanal, hesanal, butyrric, pentanal and isovaleraldehyde; b) in maleodorous dry salami: allil metil sulfide, isovaleraldehyde, butyrric acid
Determination of styrene content in Gorgonzola PDO cheese by headspace solid phase micro-extraction (HS-SPME) and gas-chromatography mass-spectrometry (GC-MS)
No full textControl of the composition of products that are intended for use as packaging material is essential, particularly when these products come into direct contact with food. It is well known that plastics are not inert and that their residual monomers, starting substances, and additives are able to migrate into the food they contact. Among plastics, styrene is a common compound found in many plastic containers that can also be produced by the oxidation of Penicillium roqueforti used in gorgonzola Protected Denomination of Origin cheese manufacturing. Therefore, solid-phase microextraction combined with gas chromatography/mass spectrometry was applied in the present work to determine the styrene content in packaged and unpackaged gorgonzola cheese samples to understand styrene migration phenomena from plastic containers
Selective determination of dihydroxyacetone in self-tanning creams by HPLC as pentafluorobenzyloxime derivative
No full textA new rapid and specific method for the determination of dihydroxyacetone (DHA) in self-tanning creams by reversed phase HPLC with UV detection was developed. DHA, together with hydroxyacetone (HA), used as internal standard, was extracted from the cream samples in a NaCl saturated aqueous solution and a small aliquot derivatized with pentafluorobenzylhydroxylamine (PFBHA) solution (10mg/mL) . The data on the time-course of the reaction showed that derivatization was completed after 5 min at room temperature in a citrate buffer at pH 4.0. The quickly formed oximes were isolated from the reaction mixture in acetonitrile after addition of NaCl saturated solution. The rapid chromatographic separation on a reversed phase C-18 column using a simple acetonitrile/water mixture followed by detection at 262 nm allowed a selective estimation of DHA in self-tanning creams currently on the national market. Quantitative yields of the oxime formation was verified by comparing responses of DHA subjected to the described procedure and of synthetic derivative previously prepared. Linearity (r2≥ 0.997), recovery (97÷105%), LOD (20 nmol) and precision (RSD ≤ 3.52%) of the method were tested
Determination of volatile compounds of precoked prawns (Penaeus vannamei) and cultured gilthead sea bream (Sparus aurata) stored in ice as possible spoilage markers using solid phase microextraction and gas chromatography/mass spectometry
No full textBACKGROUND: Solid phase microextraction (SPME) and gas chromatography/mass spectrometry (GC/MS) have been reported as useful techniques for analysing volatile compounds to monitor fish freshness. In this study, SPME/GC/MS was applied to cultured gilthead sea bream and precooked prawn stored in ice for 6 days in order to find possible markers of spoilage. Total volatile basic nitrogen (TVB-N) was also determined as a common index of spoilage.
RESULTS: The TVB-N value at the end of the storage period for cultured gilthead sea bream (302.40 ± 8.50 mg kg−1) was within the range of acceptability for edible fish (300-400 mg kg−1) but could be considered at the beginning of spoilage. For precooked prawn the TVB-N value at day 6 (863.04 ± 7.84 mg kg−1) was not acceptable for human consumption. SPME/GC/MS identified 30 compounds in cultured gilthead sea bream and 49 compounds in precooked prawn. In particular, 3-methyl-1-butanol, 2-methylbutanal, 3-methylbutanal and 3-hydroxy-2-butanone increased during refrigerated storage both in the two species investigated here and in other species reported elsewhere and could be considered as markers of spoilage.
CONCLUSION: This study confirmed that SPME/GC/MS can be considered an efficient method suitable for analysing the volatile compounds of both raw fish and fishery products in order to monitor loss of freshness
Determination of Carbon Monoxide in Tuna by Gas Chromatography with Micro-Thermal Conductivity Detector
No full textThe suitability of a portable gas chromatograph equipped with a micro-thermal conductivity detector for the head-space determination of carbon monoxide (CO) in tuna samples is
evaluated; CO is estimated after its liberation from tissue by acidic treatment at 70°C. Using the tested technique, the CO contents in untreated and suspected treated samples are analyzed. A limit of
detection of approximately 13 ng/g is reached. The results demonstrate that this apparatus has performances similar to more expensive and sophisticated instruments
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