Effect of lactate enhancement on myoglobin oxygenation of beef longissimus steaks overwrapped in PVC and stored at 4 degrees C.

摘要

Injection enhancement with lactate darkens beef; however, the mechanism is unclear. Our objective was to assess the effects of lactate on beef myoglobin oxygenation. Nine strip loins were divided in half and one of three injection treatments (negative control - not injected, positive control - injected with water, and 3% lactate - injected with a water solution of lactate) was assigned to each half using an incomplete block design. Positive control and 3% lactate loins were pumped to 110% of green weight, cut into 2.54-cm thick steaks, overwrapped in polyvinyl chloride and stored at 4 degrees C. Steak surface darkening (L*), color stability (a* and metmyoglobin-reducing activity), depth of oxygen penetration and myoglobin oxygenation (1 h at 4 degrees C) were evaluated on days 0, 7 and 12 of storage. Lactate darkened color, decreased surface myoglobin oxygenation and limited oxygen penetration compared with controls (P < 0.05). Color stability was improved (P < 0.05) by lactate injection. The darkening effect of lactate may be associated with decreased myoglobin oxygenation. PRACTICAL APPLICATIONS. Case-ready packaging has allowed beef purveyors to enhance meat with various ingredients, resulting in increased color and shelf life. Lactate is added as an antimicrobial agent; however, this beneficial effect can be somewhat diminished by lactate-induced darkening. Research assessing the mechanism(s) of lactate-induced beef color darkening is limited with previous research focused on determining the mechanism of lactate-induced color stability. The current research will give a better understanding of the role of lactate as an ingredient in beef steak darkening and, thus, provide a foundation that can be used to develop strategies to improve meat color