Acid Marination for Tenderness Enhancement of the Beef Bottom Round

Acid marination is known to improve meat tenderness. The objective of this study was to document the tenderness and color effects of marinating m. biceps femoris and to determine optimal acid levels. Acid solutions were prepared to 0.1 M (low) and 0.5 M (high) and pumped to 7% of initial wt. in experiment 1; 0.75 M (low) and 1.5 M (high) and pumped to 10 % of initial wt. in experiment 2. Lactic acid, acetic acid and sodium citrate dihydrate (food grade citric acid) at low and high concentrations gave 6 treatments per experiment. Objective color measurements were taken at 0, 1, and 8 h after marination for experiments one and two. Cooking loss and tenderness were analyzed from steaks cut at 0, 1, and 8 h and at 1, 3, 5, 7, 14, 21 and 28 d after injection and from steaks cut at 0, 1, and 8 h and at 1, 3, 5, 7, 14 d for experiments 1 and 2, respectively. Muscles were cut into steaks at 8 h and frozen at the times indicated after injection. Color was measured after given time to bloom at 0, 1 and 8 h post-injection for both experiments 1 and 2. Shear force measurements were obtained from an Instron with a Warner-Bratzler shear force attachment. No effects on tenderness (P = 0.11) were observed from experiment 1. A significant (P = 0.02) increase in tenderness was observed from 1 to 14 days during experiment 2. Sodium citrate dihydrate has little to no effect on tenderness; acetic and lactic acids at 0.75 M to 1.5 M had a positive effect on tenderness. In experiment 1, muscles marinated with 0.5 M sodium citrate dihydrate decreased in lightness (L*), whereas samples with 0.1 M lactic acid increased in L* at 1 h (P ≤ 0.05). All muscles marinated with 0.1 M sodium citrate, acetic and lactic acid increased significantly in lightness at 8 h (P ≤ 0.05). Both redness (a*) and yellowness (b*) decreased for all six treatment groups from 0 to 8 h (P ≤ 0.05) of experiment 1. There was a significant effect of treatment x time (P = 0.04) on L* values. When using either acetic or lactic acids at higher concentrations, at the injection site, the color of the meat turned from red to a dark gray. Results of this work indicate that acid marination with 0.1 to 0.5 M of the three analyzed acids had no effect on tenderness, but at higher concentrations of acid (0.75 to 1.5 M) significantly (P = 0.02) improved tenderness from 1 to 14 d. Advisor: Chris R. Calkins