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LIN/COPPE/UFRJ. ELECTRON SPIN RESSONANCE IDENTIFICATION OF IRRADIATED FOOD. Prof. Edgar Francisco Oliveira de Jesus * Prof. Ricardo Tadeu Lopes * Dr. Alexandre Malta Rossi **. *Laboratório de Instrumentação Nuclear (Escola de Engenharia/COPPE/UFRJ)
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LIN/COPPE/UFRJ ELECTRON SPIN RESSONANCE IDENTIFICATION OF IRRADIATED FOOD Prof. Edgar Francisco Oliveira de Jesus* Prof. Ricardo Tadeu Lopes* Dr. Alexandre Malta Rossi** *Laboratório de Instrumentação Nuclear (Escola de Engenharia/COPPE/UFRJ) **Centro Brasileiro de Pesquisas Físicas (CBPF)
LIN/COPPE/UFRJ H. Delincée - “Analytical methods to identify irradiated food¯¯a review” Radiation Physics Chemistry; 63, 3-6; p.455-458, 2002
LIN/COPPE/UFRJ Electron Spin Resonance (ESR)
LIN/COPPE/UFRJ Radiation Sources • “Brokhawen Portable Cesium Development Irradiator” (BPCDI) - IPE, CETEX., Guaratiba, RJ. • Césio-137 with 3,99 x 1015 Bq (108.000 Ci), in 1969 • Actual dose rate - 30.0 Gy/min • Gammacell 220 Excel - Nordion - Laboratório de Instrumentação Nuclear COPPE/UFRJ • Cobalto-60 with 3.08 x 106 Bq (12,000 Ci), in 2000 • Actual dose rate - 90 Gy/min
LIN/COPPE/UFRJ IPD Irradiator - Frontal view.
LIN/COPPE/UFRJ Gammacell Irradiator
LIN/COPPE/UFRJ ESR Measurements • Bruker ESP300E spectrometer (CBPF) • Bruker EMS104 spectrometer (LIN)
LIN/COPPE/UFRJ Alcoholic Extraction Treatment • Compact the pulp without seeds and skin, in a uniform sample; • About six grams of the pulp is treated with 40 ml 80% ethyl alcohol solution in de-ionized water; • The insoluble solid fraction is then separated by filtration; • Remove the excess of water and left to dry at ambient temperature for one hour; • 100 mg of the dry matter is then pressed in an acrylic matrix by a steel stick; • The resulting sample, consisting of a cylinder 2.5 mm in diameter and 15 mm high, is measured by ESR in a quartz tube.
LIN/COPPE/UFRJ Products • Papaya Tomato Kiwi • Apple Pineapple Strawberry • Pear Mango • Pumpkin Carrot Potatoes • Onions Garlic
LIN/COPPE/UFRJ ESR Spectra Irradiated Samples Non-irradiated Samples
LIN/COPPE/UFRJ ESR Signal Intensity Variation with Dose
LIN/COPPE/UFRJ ESR Spectra of tomato irradiated with additive doses
LIN/COPPE/UFRJ ESR Sensitivity for Different Products (Intensity/Gy) MDDose (Gy) * Cellulose (g/100g) Kiwi 5.49 0.08 94 0.94 Papaya 4.97 0.19 104 0.72 Tomato 4.22 0.22 112 0.49 Strawberry 1.92 0.23 384 0.48 Apple 2.40 0.34 238 0.56 Pineapple 3.75 0.37 146 0.60 Pumpkin 1.22 0.16 396 0.47 Carrot 2.28 0.28 222 0.54 * Calculated as the dose necessary to introduce a signal twice the background intensity for non-irradiated samples.
LIN/COPPE/UFRJ Dose Determination - Additive doses
LIN/COPPE/UFRJ ESR Intensity Decay
LIN/COPPE/UFRJ Onions
LIN/COPPE/UFRJ Garlic
LIN/COPPE/UFRJ Food Irradiation Research EMBRAPA • Fruits and other vegetal products FACULDADE DE MEDICINA VETERINÁRIA - UFF • Frog legs; • oyster; • mussel; • crab;
LIN/COPPE/UFRJ Food Irradiation Research FACULDADE DE MEDICINA VETERINÁRIA - Nova Iguaçu • Chicken; • Sausage; • Beef; • Cheese.