Intramuscular variation in mitochondrial functionality of beef <i>semimembranosus</i>

Abstract

Intramuscular color stability variations in beef semimembranosus have been reported previously. Mitochondria remain biochemically active in postmortem muscle and can influence fresh beef color stability. However, the role of mitochondrial functionality in intramuscular color variations in beef semimembranosus is yet to be examined. We examined the functionality of mitochondria isolated from outside (OSM) and inside (ISM) regions of beef semimembranosus. Semimembranosus muscles (n = 5) were collected from inside rounds of beef carcasses 48 h post-mortem and were separated to OSM and ISM steaks. Color attributes were evaluated instrumentally and biochemically on days 0 and 4 of retail display, whereas mitochondrial oxygen consumption rate (OCR) was measured on day 0 using succinate as substrate using steaks frozen during fabrication. Mitochondrial OCR was significantly greater in OSM than in ISM on day 0. The ISM steaks exhibited significantly greater redness (a* value) than OSM steaks on day 0, but OSM steaks had significantly greater redness than the ISM counterparts on day 4. During retail display, ISM steaks exhibited greater lightness (L* value) than OSM steaks. However, OSM demonstrated significantly greater color stability and metmyoglobin reducing activity than ISM throughout the display. The observed differences in mitochondrial OCR between ISM and OSM steaks indicated that mitochondrial biochemistry possibly contributes to the intramuscular color variations in beef semimembranosus. _________________________________________________________________________________________

Mitochondrial functionality and beef colour: A review of recent research

“…These enzymes play a critical role in maintaining mitochondrial functionality in postmortem muscles. Moreover, several enzymes that were specific to mitochondria were detected in the sarcoplasmic fraction, indicating variation in mitochondrial degradation between the muscles (Joseph et al, 2012;Nair et al, 2017a). For example, Joseph et al (2012) reported a greater abundance of mitochondrial aconitase in the sarcoplasmic proteome of PM compared with LL, and it exhibited a negative correlation with redness.…”

Recent Updates in Meat Color Research: Integrating Traditional and High-Throughput Approaches

“…Proteomics research demonstrated that the inner portion of the semimembranosus steaks had a greater abundance of glycolytic enzymes than their outside semimembranosus counterparts (Nair et al, 2016). Furthermore, outside semimembranosus demonstrated greater mitochondrial activity than inside semimembranosus by the end of the 4-d display (Nair et al, 2017b). Muscles with more glycolytic fibers are more color stable than muscles with oxidative fibers, which may explain animal-to-animal variation within longissimus muscles.…”

Beef Carcass Size and Aging Time Effects on Yield and Color Characteristics of Top Round Steaks

“…The advantage of the superficial anatomical locations et al, 2005). Furthermore, the superficial location within the SM has been reported to have greater MRA than the deep location (Seyfert et al, 2006;Nair et al, 2017). Nair et al (2017) reported the superficial portion of the top round had greater mitochondrial functionality.…”

“…Furthermore, the superficial location within the SM has been reported to have greater MRA than the deep location (Seyfert et al, 2006;Nair et al, 2017). Nair et al (2017) reported the superficial portion of the top round had greater mitochondrial functionality. These findings are partially attributed to the mitochondria's role in the reduction of metmyoglobin formation.…”