Effects of carbon dioxide on yield, texture and microstructure of cooked ground beef

The objective of the study was to find the effects of CO2 gas on cooking loss, instrumental hardness and microstructural changes of ground beef heated to 70–83 °C. In two experiments, ground beef was stored for 4 days in 60% CO2/39.6% N2/0.4% CO and vacuum (1), or in 100% CO2, 50% CO2/50% N2, 20% CO2/80% N2, 100% N2 and vacuum (2). In an additional experiment, slices of beef semimembransosus muscles were stored for 10 days in 100% CO2, 100% N2 and vacuum. Cooking loss of ground beef patties was higher of all CO2 treatments than non-CO2 treatments (p<0.05). Storage of raw ground beef in CO2 caused a concentration dependent decrease in raw meat pH of up to 0.12 units in 100% CO2. In the beef slices, small CO2 related fissures and pores were formed in the cooked meat. These changes in pH and microstructure probably contributed to the elevated cooking loss. The hardness of cooked ground beef was not affected by CO2 exposure (p>0.05). Because CO2 in concentrations of 20–100% is commonly used in industrial packaging processes for retail meat and meat trimmings, a reduction in cooking yield of 1–3% may have sensory and economic implications.