Efficacy of multi-stage sous-vide cooking on tenderness of low value beef muscles

Two sous-vide cooking methods were tested for how effective they were in increasing tenderness of Canada AA beef chuck tenders (supraspinatus) and beef knuckles (rectus femoris) aged for 10 d. One method cooked vacuum-packaged steaks at 59C for 4 h (single-stage sous-vide: S-SV), and the other cooked them at 39C for 1 h, then at 49C for another 1h, and finally at 59C for 4 h (multi-stage sous-vide: M-SV). The control treatment (Ctl) was cooking bagged steaks in 70C water until they reached 59C (~22 min). Steaks were cooled rapidly following cooking, then refrigerated for up to 2 wks. Meat was then reheated on a grill to an internal temperature of 55C, and while still warm, underwent tenderness testing. The results showed that S-SV meat was 17-21% more tender than Ctl, and that M-SV became a further 5-6% more tender. The changes seen appeared to be consistent with the action of residual native enzymes in the meat, which, when selectively activated by specific temperatures, worked to break down muscle fibers and the connective tissue holding them together. The practical implication is that a cut which is lower value because of toughness could possibly be substituted for a higher value cut if the lower value cut is cooked with the M-SV method.