Cooking rate, pH and final endpoint temperature effects on color and cook loss of a lean ground beef model system

To assess the effects of pH, heating rate and endpoint temperature on instrumental and visual color of ground beef, pH was adjusted to 5.2–6.4, samples were heated at 0.7°C or 3°C/min to 55, 60, 65, 70, 75 or 80°C in a water bath. Cooking rate had no effect on cook loss, instrumental or visual color. Regression equations for linear, quadratic and/or cubic effects of pH and/or endpoint temperature were significant for most color indices. Amount of variance explained by the model and R² was increased by adding the calculated percentages of metmyoglobin and/or deoxymyoglobin to the regression models. The predicted sensory brownness score (0=very pink, 7.5=intermediate pink/brown, 15=intense brown) for samples with pH 5.75 cooked to 70°C was 9.75. Samples with a pH of 5.5 achieved this brownness score at 67°C. Samples with a pH of 5.2 achieved this brownness at 58°C.