Effects of irradiation on trans fatty acids formation in ground beef

In order to give the consumer the assurance that meat processed by irradiation is a safe product, a great deal of research has been developed in the world. The effect of irradiation on the hygienic quality of meat and meat products is considered as related to the control of meat-borne parasites of humans; elimination of pathogens from fresh meat and poultry; and elimination of pathogens from processed meat. Lipid oxidation and associated changes are the major causes of the quality deterioration of meat during storage. Irradiation of lipids induces the production of free radicals, which react with oxygen, leading to the formation of carbonyls, responsible for alterations in food nutritional and sensorial characteristics. Trans fatty acids are present in ground beef and can also be formed during its processing. Interestingly, the trans fatty acids, due to their chemical and physical characteristics, show more resistance to the oxidizing process. This property motivated us to investigate the level of the trans fatty acids, as well as the level of oxidation in irradiated ground beef. Irradiation of ground beef was performed by gamma rays from a ⁶⁰Co source. The applied radiation doses were 0; 1.0; 2.0; 3.0; 4.0; 5.0; 6.0; 7.0 and 8.0 kGy. Lipid peroxidation in terms of TBA number and carbonyl content was monitored during storage. The sample characteristics and trans fatty acids composition were measured, following irradiation and after 60 and 90 days of storage at –10°C.     

Orchid flowers tolerance to gamma-radiation

Cut flowers are fresh goods that may be treated with fumigants such as methyl bromide to meet the needs of the quarantine requirements of importing countries. Irradiation is a non-chemical alternative to substitute the methyl bromide treatment of fresh products. In this research, different cut orchids were irradiated to examine their tolerance to gamma-rays. A 200 Gy dose did inhibit the Dendrobium palenopsis buds from opening, but did not cause visible damage to opened flowers. Doses of 800 and 1000 Gy were damaging because they provoked the flowers to drop from the stem. Cattleya irradiated with 750 Gy did not show any damage, and were therefore eligible for the radiation treatment. Cymbidium tolerated up to 300 Gy and above this dose dropped prematurely. On the other hand, Oncydium did not tolerate doses above 150 Gy.     

Effect of gamma-irradiation on the levels of total and cis/trans isomers of beta-carotene in dehydrated parsley

Ionizing radiation is a method for preservation of foods that use the high energy of gamma rays or accelerated electrons, thereby ionizing molecules. The most important precursor of vitamin A is β-carotene, a carotenoid with pro-vitamin A activity. The highly unsaturated chain confers the instability of β-carotene, and some reactions, as isomerisation, can reduce the characteristics of pro-vitamin A. The present study investigated whether increasing doses of 0, 10 and 20 kGy lower the total β-carotene level and if an enhancement of cis-isomers occurred on samples of dehydrated parsley. No differences were observed of either fractions analyzed at doses applied in this study, nor did it contribute to the decrease of vitamin A.