Efeitos do congelamento prévio, temperatura de maturação e tratamento por ultravioleta sobre a maturação acelerada da carne bovina

Abstract

The objective of this work was to evaluate the effects of freezing/thawing, aging temperature and ultraviolet treatment on the accelerated beef aging. Samples of the Longissimus lumborum muscle from Nellore cattle, obtained 48 h postmortem, were subjected to two experiments: the first was the study of the tenderness kinetics (fragmentation index, cooking loss and shear force) and microbiological development (total microbial count) in beef, non- frozen or frozen and thawed, vacuum-packed and aged at different temperatures (1, 7, 14 and 20°C) for up to 6 days for technological characteristics and up to 4 days for microbiological analyzes; and the second experiment was the study of the kinetics of microbiological inactivation (total microbial counts and inoculated Brochothrix thermosphacta microorganism), by the Weibull model, in vacuum-packed meats subjected to different doses of UV-C radiation (13.3 to 66.6 mJ/m2). In the first experiment, only the shear force was affected (P<0.05) by the interaction between pretreatment and aging time. The fragmentation index (FI) was lower (P<0.05) in frozen and thawed meats than in those without prior freezing. FI reduced (P<0.05) with increases in temperature and aging time, indicating greater proteolysis of the myofibrillar structure. Cooking loss was not affected (P>0.05) by pretreatment, but increased (P<0.05) with increases in temperature and aging time. The total microbial count increased (P<0.05) with increases in temperature and aging time. In the second experiment, the total microbial and Brochothrix thermosphacta counts reduced with increasing UV-C radiation dose and this reduction can be described by the Weibull model. The highest dose of 66.66 mJ/cm2 of UV-C radiation provided a reduction greater than one logarithmic cycle for the total microbial (-1.2 log CFU) and the Brochothrix thermosphacta (-1.4 log CFU) counts. The results suggest that the use of high aging temperatures combined with frozen/thawed UV-C irradiation treatments can be an alternative to reduce the aging time with quality maintenance and guarantee of microbiological safety.