A comparison of γ-irradiation and microwave treatments on the lipids and microbiological pattern of beef liver

Abstract

RESUMEN Comparación de los tratamientos por irradiación γ y microondas en los lípidos y aspectos microbiológicos del hígado de vaca.Se estudiaron los efectos de los tratamientos por irradiación γ (0, 2.5, 5 y 10 kGy) y microondas (generados en un horno a nivel bajo y de descongelación durante 0.5, 1 y 2 min) sobre la composición química y aspectos microbiológicos de las muestras de hí-gado de vaca. Los análisis químicos y microbiológicos se llevaron a cabo en hígado de vaca tratado y no tratado al inicio y durante el almacenamiento en congelador a -18 o C durante 3 meses. Los análisis químicos de los lípidos de hígado de vaca mostraron que los índices de acidez, peróxido y TBA se incrementaron ligeramente después de los tratamientos por irradiación y durante el almacenamiento en congelador (-18 o C). Por el contrario, el índice de yodo disminuyó en el hígado de vaca tratado.Los tratamientos de irradiación redujeron considerablemente el recuento de bacterias totales en hígado de vaca. El porcentaje de reducción de carga bacteriana por el hígado de vaca expuesto a microondas generados de un horno con un modo de descongelación de 2 min y después de 3 meses a -18 o C fue del 62%. La carga bacteriana por el hígado de vaca expuesto a irradiación γ a 10 kGy después de 3 meses y -18 o C disminuyó al 98%. Por lo tanto, los tratamientos de irradiación γ fueron mejores que los tratamientos por microondas para la reducción de los microorganismos asociados con el hígado de vaca. La Salmonellae no se detectó en hígado de vaca no-irradiado e irradiado a través del período de almacenamiento. PALABRAS-CLAVE: Congelador -Hígado de vaca -Lípidos -Microondas -Microorganismos -Radiación γ. SUMMARY A comparison of γ-irradiation and microwave treatments on the lipids and microbiological pattern of beef liver.The effects of γ-irradiation (0, 2.5, 5 and, 10 kGy) and microwaves (generated from an oven at low and defrost settings for 0.5, 1 and 2 min) treatments on the chemical composition and microbiological aspects of beef liver samples were studied. The chemical and microbiological analyses were performed on the non-treated and treated beef liver immediately after treatments and during frozen storage (-18 o C) for 3 months. The chemical analyses of beef liver lipids showed that acid, peroxide and TBA values were slightly increased after irradiation treatments and also during frozen storage (-18 o C). On the contrary, iodine value of the treated beef liver was decreased.Irradiation treatments remarkably reduced the total bacterial counts in beef liver. The percent reduction of bacterial load for beef liver exposed to microwaves generated from an oven at defrost mode for 2 min and after 3 months at -18 o C was 62%. The bacterial load for beef liver exposed to γ-irradiation at 10 kGy after 3 months at -18 o C was decreased by 98%. Hence, γ-irradiation treatment was far better than microwave treatment for reduction of the associated microorganisms with beef liver. Salmonellae was not detected in non-irradiated and irradiated beef liv...

Assessment of conventional and microwave heating induced degradation of carotenoids in olive oil by VIS Raman spectroscopy and classical methods

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Electrophoretic patterns of microwaved and γ‐irradiated beef liver proteins

“…The biochemical variations occurring in beef liver proteins due to exposure to microwaves generated at defrost oven power setting are shown in Table 5 and Fig 3. In general, the number of bands was lower in microwaved 14,15 than in non-microwaved beef liver. 16 Dramatic changes in the band type and concentration were found as a result of exposure to microwaves for different periods.…”

“…14 The production of ammonia (deamination of amino acids) and the presence of fatty and keto acids as part of the radiolytic products indicated protein destruction. In addition, the total microbial counts 15 of the beef liver samples under study demonstrated the presence of associated micro-organisms. During frozen storage the microbial counts decreased and the exposure to microwaves and g-radiation caused a further reduction in microbial counts.…”

Assessment of Microwave versus Conventional Heating Induced Degradation of Olive Oil by VIS Raman Spectroscopy and Classical Methods

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