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|Título:||Ultra-high Pressure LC to Determine α-Tocopherol and BHT in Active Plastic Films and to Evaluate their Migration into a Fatty Food Simulant|
|Editora:||Instituto Nacional de Saúde Doutor Ricardo Jorge, IP|
|Resumo:||The use of food additives is not restricted to its direct addition to food products and they can also be added to the food packaging which, acting as a reservoir, is able to release it by means of a diffusion mechanism. Low density polyethylene (LDPE) films containing α-tocopherol and BHT, separately or together, with different nominal concentrations have been prepared through a two-step process; first preparation of pellets and then their extrusion. Plastic films were extracted with acetonitrile for 24 h. Extracts were filtered and analyzed by means of an Ultra-High Pressure Liquid Chromatography (Ultra Performance Liquid Chromatography, UPLC) method with diode array detection (DAD). The analytical column (UPLC BEH, 5 x 2.1 mm, 1.7 µm particle size) was used at 30 ºC. A gradient elution method was employed with ultrapure water and acetonitrile. The flow rate was 0.3 ml/min and the injection volume was 10 µl. α-tocopherol was detected at 295 nm and BHT at 277 nm. A calibration curve was obtained in order to quantify the amount of extracted a-tocopherol and BHT. Excellent linearity was obtained for both a-tocopherol and BHT (r2= 0.999) in the range 1-100 µg/ml. Results showed that the film prepared with 1% of α-tocopherol lost a high amount of this antioxidant during processing. On the contrary, films prepared with both α-tocopherol and BHT presented a significantly lower loss. In fact, the residual amount of α-tocopherol after processing was 73% of the initial amount in the case of the plastic film with 0.5% of α-tocopherol and 0.5% of BHT. This means that BHT protects α-tocopherol from degradation, as intended. The migration of the LDPE with 0.25% α-tocopherol and 0.25% BHT into ethanol 95% (v/v), an alternative fatty food simulant, was evaluated at different time contact periods (1, 2, 4, 7, 10, 20 and 30 d), and at different temperatures. The plastic submitted to the migration test was then, extracted in order to evaluate the remaining concentration in the plastic film. The sum of both values is in agreement with the amount found in the initial evaluation of the plastic concentration after processing.|
|Aparece nas colecções:||DAN - Posters/abstracts em congressos internacionais|
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|HPLC2011_Active packaging.pdf||302,83 kB||Adobe PDF||Ver/Abrir Acesso Restrito. Solicitar cópia ao autor!|
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