Relationships between DNAJA1 Expression and Beef Tenderness: Effects of Electrical Stimulation and Post-mortem Aging in two Muscles

Abstract

Previous studies have demonstrated that DNAJA1 could be a good indicator of beef toughness in Longissimus thoracis muscle from Charolais young bulls. This study aimed to check if relationship between DNAJA1 expression and beef tenderness is valid in two muscles, which differ in toughness from Angus steers with or without electric stimulation at different times of post-mortem ageing. Electric stimulation did not significantly affect DNAJA1 expression at the time of slaughter. But, RNA degradation soon after slaughter was a major factor, which affected the assessment of DNAJA1 expression, even at 3 h post-mortem. Correlation of DNAJA1 expression at slaughter with shear force values varied according to ageing time (24 h, 3, 7, 14 or 21 days post-mortem) or according to the use of electric stimulation and was not significantly correlated with any of these shear force peak values despite a few high correlation values (-0.60 or +0.34). In conclusion, DNAJA1 is not an omnipotent marker of beef toughness with this particular data set since the correlation of its expression level with shear force values varies according to slaughtering conditions and ageing time.

Assessing the impact of Bos taurus x Bos indicus crossbreeding and postmortem technologies on the eating quality of loins from pasturefinished young bulls

“…Improvement of tenderness by meat aging involves several proteolytic systems responsible for the degradation of muscle proteins (Sami et al, 2015). Generally, the tenderness of beef improves significantly over the aging period in a musclespecific manner (Nair et al, 2019).…”

“…In the latter study, the vacuum aging treatment increased the proportion of tender loin steaks from 42.9 % (aged for 2 d) to 71.4 % (aged for 14 d). According to Sami et al (2015) to effectively tenderize longissimus muscles (i.e., by reaching a WBSF < 43.0 N) the vacuum aging period had to last at least 21 d. In fact, Vilella et al (2019) reported that 28 dvacuumaged samples resulted in lower WBSF values than those from the control group, and 87 % of the aged steaks were classified as tender (WBSF < 40.1 N).…”