Combined effects of gamma irradiation and aging on tenderness and quality of beef from Nellore cattle.

Combined effects of gamma irradiation (0, 3, 6 and 9 kGy) and aging (1 and 14 days) on quality attributes of vacuum-packaged beef from Nellore cattle were evaluated. The meat water holding capacity was affected by irradiation, increasing (p < 0.05) purge and cooking loss regardless of the dose used. Irradiation negatively affected myofibrillar fragmentation, but samples irradiated at 9 kGy had (p < 0.05) higher soluble collagen and lower shear force values. The meat metmyoglobin reducing activity was reduced (p < 0.05) by the irradiation process, inducing the metmyoglobin accumulation with increasing dose applied. Samples irradiated at 9 kGy presented (p < 0.05) higher lipid oxidation and lower oxymyoglobin proportion and color redness and chroma values. It was concluded that irradiation at 9 kGy combined with aging can be used as an effective tool for improving the tenderness of Nellore beef, but resulted in a discoloration of the beef.