The impact of postharvest interventions on the color stability and, subsequently, the palatability of beef from cattle fed wet distillers grain1

Abstract

Two hundred forty heifers were fed at Oklahoma State University in Stillwater, OK, in 1 of 2 treatment groups: a dry rolled corn (CON) diet or a diet including 30% wet distillers grains plus solubles (WDGS). Chuck rolls (n = 60) and paired strip loins (n = 75 pairs; 38 CON and 37 WDGS) were collected from each treatment group and processed at 3 d and 14 d, respectively. After grinding, each chuck was separated into 8 polyvinyl chloride (PVC) film overwrapped packages and 8 high oxygen modified atmosphere packaging (MAP), each containing approximately 0.23 kg of ground beef, for evaluation by a trained color panel, a trained color panel and a trained sensory panel and for thiobarbituric acid reactive substance (TBARS) analysis. After 14 d, 1 strip loin from each pair was injected with an enhancement solution. Steaks from each strip loin were fabricated and packaged, one-half in PVC and one-half in MAP. In addition to the evaluation by trained color and sensory panels and TBARS analysis, steaks were subjected to instrumental color evaluation using a HunterLab Miniscan XE and Warner-Bratzler Shear Force analysis using an Instron Universal Testing Machine. Ground beef exhibited no significant differences in color between dietary treatments; however, sensory panelists did find MAP WDGS had less beefy flavor (P = 0.05) and more painty flavor (P = 0.01) intensities than the MAP CON ground beef. Cattle fed WDGS discolored more (P = 0.01) and had less bright steaks than cattle fed the CON when MAP and enhanced. Distillers fed, nonenhanced (nonE) MAP steaks were redder and yellower than control steaks (P < 0.05) on removal from simulated retail display. There were no other significant (P > 0.05) color differences between dietary treatments using any other combination of postharvest interventions. Sensory panel results indicated WDGS NE PVC products were juicier and more tender (P < 0.05), initially, and contained less connective tissue (5.3 ± 0.1, 5.5 ± 0.1, and 5.9 ± 0.4, respectively) than the steaks from CON carcasses (5.1 ± 0.1, 5.4 ± 0.1, and 5.8 ± 0.4, respectively). Although WDGS NE MAP steaks showed more oxidation than CON NE MAP steaks on removal from retail case, all TBAR values were well below a threshold of 1 mg malonaldehyde/kg. Essentially, MAP but not enhancing products from cattle fed WDGS may be the best way to maintain a visually appealing appearance in the retail case but at possible risk to product juiciness.