Maturação acelerada da carne bovina combinada com aplicação da radiação gama

Abstract

The need to solve the inconsistency in Brazilian beef tenderness the effects of gamma irradiation (3 kGy) on beef quality (M. Longissimus lumborum) during aging (1, 4, 7, 14 and 21 days) under different temperatures (1, 7 and 15 °C) were evaluated. The water retention capacity was lower (P < 0.05), while purgue and cooking losses were higher (P < 0.05) in the irradiated samples. The samples aged at 7 and 15 °C also presented a higher (P < 0.05) purgue. There was a reduction (P < 0.05) in the insoluble and total collagen contents in irradiated and aged at 7 and 15 °C samples, which did not occur (P > 0.05) in the non-irradiated ones. The increase in the aging temperature provided (P < 0.05) a higher myofibrillar fragmentation index and less shear force. However, irradiation provided (P < 0.05) less myofibrillar fragmentation and greater shear force. The aging temperature did not affect (P > 0.05) the myoglobin chemical forms neither the CIE color indexes, but the irradiation provided (P < 0.05) lower oxymyoglobin content and luminosity (L*). The protein oxidation was not affected (P > 0.05) by irradiation, being higher (P < 0.05) in samples aged for 14 days at 15 °C. The lipid oxidation was higher (P < 0.05) in the samples irradiated and aged at high temperatures (7 and 15 °C) for 14 days. The mesophilic and lactic acid bacteria counts were higher (P < 0.05) in non-irradiated samples aged at 7 and 15 °C. The irradiation reduced (P < 0.05) the mesophilic count in all the treatments, keeping below the maximum acceptable limit (107UFC/g) during the 21 days of aging. The use of higher aging temperatures increased (P < 0.05) the formation of volatile compounds related to the deterioration processes (lipid and protein oxidations and microbial development), being higher (P < 0.05) in the non-irradiated samples aged at 15 °C. The irradiation had little effect on the volatiles profile, being the dimethyl sulfide the main compound formed and presenting the potential for use as an irradiation marker. Refrigeration temperatures higher than the conventional (1 °C) in the aging process can be usedto accelerate the beef tenderization when gamma irradiation (3 kGy) was applied as a microbial development control. The ideal binome temperature/time during aging must still be defined, suggesting appling temperatures of 7 °C in the first 7 days of aging.