Efficacy of multi-stage sous vide cooking on steaks from lower value beef muscles

Sous-vide cooking is slow-cooking of vacuum-packaged food in water under precise temperature control, and is a popular cooking method in the food service industry. Meat held at temperatures conducive to endogenous proteolytic enzyme activity may become more tender. For each of the rectus femoris (RF; knuckle; moderately tender) and supraspinatus (SS; Scotch tender; moderately tough) 72 boxed Canada Grade AA muscles aged 10 d were purchased over 12 months. In 6 groups of 12, each muscle was cut into 6 3 cm steaks which were first assigned to one of three cooking treatments (waterbath (WB; control) at 70° C to internal temperature of 59° C; single-stage sous-vide (S-SV) at 59° C for 4 h; multi-stage sous-vide (M-SV) at 39° C for 1 h, 49° C for 1 h, 59° C for 4 h) then stored either for 1 wk at 2° C or for 2 wk at -1.5° C. Steaks were reheated by grilling at 210° C to 55° C, subsampled, and while warm tested for tenderness with slice shearing, and for structural integrity with a 4-cycle penetrative deformation test at 65% strain.

Storage had no meaningful significant effects (P > 0.0001). Cooking losses were 5-7% greater for meat cooked under SV. Peak force (Pk) and myofibrillar strength (1st inflection) differed among all treatments for the SS (WB > S-SV > M-SV; P < 0.0001), but differed only from the control for the RF (WB > S-SV = M-SV; P < 0.0001). For both muscles, connective tissue strength (Pk – 1st inflection) was weakened with SV cooking (WB > S-SV = M-SV; P < 0.0001). Overall, tenderness was increased by 17-19% with S-SV, and a further 5-7% with M-SV. During 4 cycles of deformation the resilience and therefore cohesiveness of the SS deteriorated quickly after the first compression (P > 0.0001). The RF deteriorated more slowly, with WB meat showing the greatest structural integrity (WB > S-SV = M-SV; P < 0.0001). SV cooking was markedly effective in increasing tenderness. M-SV was effective in increasing tenderness beyond S-SV although the degree of response differed for the muscles tested.