Efeito da radiação gama sobre as características microbiológicas, físico-químicas e sensoriais da carne bovina in natura

Abstract

Aiming at improving the conservation and acceptance of fresh beef by the consumer, this work seeks actions aimed at maintaining and / or improving technological, microbiological, sensory and volatile characteristics through the application of low doses of gamma radiation. Samples striploin (M. Longissimus thoracis) were irradiated (0.75; 1.5; 2.25; and 3.0 kGy) and distributed in six

times (1, 14, 28, 42, 56 and 70 days) refrigerated storage (4 ° C). As a control, samples of non- irradiated steaks were stored under the same conditions. The irradiation did not affect (P> 0.05) the

values of purging and loss of mass during cooking. The values of pH and shear force decreased (P <0.05) with the storage time, but higher values were observed for samples irradiated in the highest doses. It was observed (P <0.05) an increase as storage time and irradiation dose in the proportion of metmyoglobin, which induced lower (P <0.05) values of saturation and tonality angle in the surface color of the meat. Higher doses of irradiation reduced (P <0.05) the development of psychrotrophic bacteria and lactic acid with the storage time. A total of 22 volatile compounds were detected in the samples, 4 of which (nonanal, methylbenzene, hexane and 2-butanone) increased considerably with irradiation. Higher concentrations of aldehydes, hydrocarbons and aromatic compounds were observed (P <0.05) in samples subjected to higher doses of irradiation. The threshold for detecting aroma change by the irradiation dose was 0.98 kGy, but all irradiated samples were (P <0.05) rejected. The sensory attributes aroma, flavor and texture of the irradiated and cooked samples were perceived (P <0.05) as different from the non-irradiated samples. Lower acceptance scores were observed (P <0.05) in samples irradiated by higher doses. It was concluded that, although the use of gamma radiation doses as low as 0.75 kGy are able to increase the useful life of vacuum-packed meat by up to 14 days, the deleterious effects observed may limit its commercialization.