Mitochondrial functionality and beef colour: A review of recent research

Abstract

The bright-red colour of meat that consumers prefer depends on the depth of oxygen diffusion into the tissue and myoglobin oxygenation. Interestingly, both processes are influenced by mitochondrial activity in postmortem muscle. The transition of muscle metabolism from aerobic to anaerobic pathways affects various cellular processes including mitochondrial functionality. Numerous studies report that even with compromised structure, mitochondria continue to influence postmortem beef colour via oxygen consumption and metmyoglobin reducing activity. Hence, an in-depth understanding of the pre-and post-harvest factors affecting mitochondrial functionality can significantly enhance existing knowledge of meat colour and colour stability. Several comprehensive reviews have discussed the biochemical factors affecting meat colour, but there are only a few that have sections on the impact of mitochondria on beef colour. Furthermore, advancement of high-throughput techniques such as metabolomics and proteomics has enabled researchers to elucidate metabolite and protein changes related to mitochondria. Therefore, the objective of this review is to provide an overview on the role of mitochondria in beef colour, with a focus on recent advances in mitochondrial research, oxygen consumption, and metmyoglobin reducing ability.

Influence of ultimate pH on biochemistry and quality of Longissimus lumborum steaks from Nellore bulls during ageing

“…The instrumental colour results from both Normaland Intermediate-pH u groups indicated an appearance of fresh red meat, probably due to the metabolic processes including myoglobin oxygenation and the oxidative status of haem iron during the muscle postmortem period (Ramanathan et al, 2019). Indeed, Normal-pH u promotes denaturation of the globin moiety of myoglobin, an effect which exposes the haem group and increases its susceptibility to oxidation forming metmyoglobin.…”

New alternatives for improving and assessing the color of dark–cutting beef – a review

“…Higher postmortem muscle pH is the most important factor that can prolong mitochondrial functionality (Ramanathan et al, 2019). Previous reports state that the mitochondria from dark-cutting beef has progressively greater O 2 consumption and higher level of MMb reductase activity as the pH of dark-cutting meat increases (McKeith et al, 2016;Wu et al, 2020).…”

“…The decrease in O 2 concentration within the myofibrils favors the formation of DMb and the color of fresh beef turns to dark purple (Ramanathan et al, 2019). Since the O 2 depth depends on the O 2 concentration in the medium, oxygenation by means of air-exposition (approximately 20 % O 2 ) would not result in a thick OMb layer on dark-cutting beef surfaces.…”

“…Therefore, at a certain point, the oxidative pressure by fluorescent illumination, the amount of ROS produced in mitochondrial respiration, or other factors will promote Mb oxidation that will be noticeable on the surface of the muscle (Bekhit and Faustman, 2005;Ramanathan et al, 2019;Renerre, 1990) which leads to lower discoloration over the display time because of the accumulation of MMb on the meat surface (Renerre, 1990). In short, low O 2 tension, pH u up to 5.8, high temperature, concomitant lipid oxidation and loss of MMb-reducing activity are amongst the factors that influence iron oxidation (Bekhit and Faustman, 2005;Mancini and Hunt, 2005).…”

“…Kim et al (2006) reported that color stabilization by lactate enhancement is related to MRA, by NADH replacement via LDH, reducing NAD+ both enzymatically and non-enzymatically. However, NADH can also promote mitochondrial O 2 consumption resulting in darkened muscle because of the lowering of Mb oxygenation (Ramanathan et al, 2019). Lactate also results in color stabilization of cooked beef (Knock et al, 2006).…”