Changes in the Sarcoplasmic Proteome of Beef Muscles with Differential Color Stability during Postmortem Aging

Abstract

Beef color is a muscle-specific trait, and sarcoplasmic proteome influences muscle-specific variations in beef color stability. Postmortem aging influences the color and sarcoplasmic proteome of beef muscles. Nonetheless, muscle-specific changes in sarcoplasmic proteome of beef muscles with differential color stability during aging have not been characterized yet. Therefore, our objective was to examine the changes in the sarcoplasmic proteome of 3 differentially color stable muscles from beef hindquarters during postmortem aging. Longissimus lumborum (LL), psoas major (PM), and semitendinosus (ST) separated from 8 (n = 8) beef carcasses (24 h postmortem) were subjected to aging in vacuum packaging (2°C) for 0, 7, 14, and 21 d. On each aging day, steaks were fabricated, and allotted to refrigerated storage (2°C) under aerobic packaging. Samples for proteome analysis obtained during fabrication were frozen at –80°C. Instrumental color and metmyoglobin reducing activity were evaluated on d 0, 3, and 6 of storage. Sarcoplasmic proteome was analyzed, and differentially abundant proteins were identified using mass spectrometry. Color attributes and biochemical parameters were influenced by muscle source and aging (P < 0.05); LL and ST had greater (P < 0.05) surface redness than PM. Aging also influenced surface redness, with 7-d aged steaks demonstrating greatest values (P < 0.05). Proteome analysis identified 135 protein spots differentially abundant (P < 0.05) between the muscles and aging time points indicating muscle-specific changes during aging. The identified proteins included glycolytic enzymes, proteins associated with energy metabolism, antioxidant proteins, chaperones, and transport proteins. Overall, the glycolytic enzymes were more abundant (P < 0.05) in color-stable muscles and at aging times with greater color stability, indicating that these proteins could be used as potential biomarkers for beef color.

Intramuscular Variations in Color and Sarcoplasmic Proteome of Beef Semimembranosus during Postmortem Aging

“…The MRA values de- (Nair et al, 2018). One possible explanation for this unexpected observation is that the combination of aging and long-term storage of an already color-labile ISM leads to extensive mitochondrial damage and the release of mitochondrial reducing enzymes, which in turn could lead to the observed increase in MRA values.…”

“…Joseph et al (2012) also reported a greater abundance of β-enolase and creatine kinase in color-stable beef longissimus lumborum steaks than in color-labile psoas major steaks. Moreover, recently, Nair et al (2018) reported that the color-stable longissimus lumborum and semitendinosus steaks had greater abundance of glycolytic enzymes and creatine kinase compared to psoas major steaks during postmortem aging.…”

“…Beef color stability is a muscle-specific trait, and various muscles in a beef carcass discolor at different rates (Hunt and Hedrick, 1977a;O'Keeffe and Hood, 1982;McKenna et al, 2005). From this standpoint, the biochemical bases of intermuscular variations in beef color have been studied extensively (McKenna et al, 2005;Seyfert et al, 2006;Joseph et al, 2012;Wu et al, 2016;Nair et al, 2018).…”

“…Proteomic approaches have characterized the fundamental basis of color stability variations in fresh beef, such as muscle-specificity (Joseph et al, 2012;Wu et al, 2016;Nair et al, 2018) and animal effect (Canto et al, 2015). Previous investigations (Nair et al, 2016) on beef ISM and OSM steaks (48 h postmortem) reported an increased abundance of glycolytic enzymes in sarcoplasmic proteome of ISM, which could possibly lead to a faster pH drop in ISM during the postmortem period while the carcass temperature is still high.…”

“…Marino et al (2014) reported that aging can affect color, pH, and water holding capacity of meat by altering the sarcoplasmic protein patterns. Moreover, recent research (Nair et al, 2018) reported that aging affects intermuscular variations in color and the sarcoplasmic proteome profile. However, the effect of aging on intramuscular color variations and the sarcoplasmic proteome profile of beef semimembranosus has not been examined yet.…”