Filters
Results 1 - 1 of 1
Results 1 - 1 of 1.
Search took: 0.019 seconds
[en] Radiation-induced chemical changes in foods are generally very small at the usual processing doses. Some exception is radiation degradation of lipids, which are the components most susceptible to oxidation. A possible use of lipid hydroperoxides (LOOH) as indicators of irradiation is described for whole egg and egg yolk powders. A sensitive and reproducible spectrophotometric method for LOOH measurement based on feric thiocyanate, as modified in our laboratory, was applied. This method enabled the determination of LOOH, including oleic acid hydroperoxides, which is usually not possible with some other frequently used methods. The lowest limit of 0.05 mmol LOOH/kg lipid could be measured. The measurements were performed in various batches of whole egg and egg yolk powders by the same producer, as well as in samples supplied by various producers. Baseline level in unirradiated egg powder 0.110 ± 0.067 mmol LOOH /kgL was established. The formation of LOOH with dose, as well as the influence of age, irradiation conditions, storage time and storage conditions on LOOH were investigated. The irradiation of whole egg and egg yolk powders in the presence of air revealed an initially slow increase of LOOH, caused by an inherent antioxidative capacity, followed by a fast linear increase after the inhibition dose (Do). In all investigated samples Do of 2 kGy was determined. Hydroperoxides produced in irradiated materials decay with time. In whole egg and egg yolk powders, after an initially fast decay, the level of LOOH continued to decrease by the first-order decay. Nevertheless, after a six months storage it was still possible to unambiguously identify samples which had been irradiated with 2 kGy in the presence of air. Reirradiation of these samples revealed a significant reduction of Do to 1 kGy. In samples irradiated with 4 kGy and kept under the same conditions, the shortening of Do to 0.5 kGy was determined by reirradiation. This offers a possibility for the estimation of the original irradiation dose. Alternative methods of generation of LOOH in egg powder were investigated, as well as possible methods of destroying it after irradiation. Keeping egg powder at an elevated temperature for an extended period of time or boiling in water proved unsuccessful in either generating or destroying detectable LOOH
Source
D'Alberti, F.; Osimani, C. (eds.); Associazione Italiana di Radioprotezione, (Italy); International Radiation Protection Association, (United States); [1 CD-ROM]; ISBN 88-88648-09-7; 
; 2002; [1 p.]; European IRPA Congress 2002; Florence (Italy); 8-11 Oct 2002; Also available from http://www.airp-asso.it/docs/cd_airp_irpa/irpa2002.pdf; The full paper was not sent on time to be published on these Proceedings.
; 2002; [1 p.]; European IRPA Congress 2002; Florence (Italy); 8-11 Oct 2002; Also available from http://www.airp-asso.it/docs/cd_airp_irpa/irpa2002.pdf; The full paper was not sent on time to be published on these Proceedings.