No abstract

Palavras-chave: Escurecimento de carne bovina; Tempo de exposição de carne à luz fluorescente; Atividade redutora da metamioglobina; Mioglobina; Oxidação lipídica.

This study aimed to improve the color and oxidative stabilities of dark Nellore bull steaks with greater-than-normal ultimate pH (pHu) by the injection (8% raw wet weight basis) of a solution with L-lactate (2.5%), phosphate (0.3%) and rosemary extract (0.06%), with further packaging in high oxygen atmosphere (HiOx MAP). Longissimus lumborum muscles from pasture-fed Nellore bulls were divided into three pHu ranges: normal (<5.80), intermediate (5.81–6.19), and high (≥6.2). Muscles were then halved, with sections were randomly assigned to non-enhanced (C, n = 6/pHu range) or injected (E, n = 6/pHu range) groups, at 72 h postmortem. Each section was cut into 2 cm-slices, which were HiOx-packed and then stored for 5 days (dark) and displayed for 9 days (fluorescent lighting) at 2 °C. Higher pHu steaks exhibited greater a*, b*, h*, C* and surface oxymyoglobin and lower surface deoxymyoglobin and oxygen consumption compared to those of normal pHu between days 0 and 5 (p < 0.05). Over the time, normal-pHu muscles showed oxidative protection (lower TBARS and greater metmyoglobin reducing ability values, p < 0.05) in enhanced-steaks. Therefore, enhancement and HiOx MAP seem to produce greater-than-normal pHu Nellore bull steaks with a preferable color and quality, even after display time.