Einfluss von MAP-verpackungen auf die farbstabilität von rindersteaks

The objective of the present study was to determine the influence of different modified atmosphere packaging (MAP) systems on premature browning (PMB) in steaks from beef Longissimus lumborum (LL) muscles. LL muscles from 16 (n = 16) beef carcasses (USDA Select grade) were fabricated into 2.5 cm steaks. Steaks were individually packaged in vacuum (VP), high-oxygen MAP (HIOX; 80% O₂ + 20% CO₂), or carbon monoxide MAP (CO; 0.4% CO + 19.6% CO₂ + 80% N₂), and stored for 5 days at 4 °C in the dark. At the end of storage, steaks were cooked to an internal temperature of 66 °C or 71 °C, and internal cooked colour was analysed. HIOX steaks exhibited lower redness (a^* value) than steaks in VP and CO MAP. LL steaks stored in HIOX were more susceptible to PMB at 66 °C than steaks in VP and CO. Our results indicated that CO MAP and VP could be used as effective packaging strategies to minimise premature browning in whole-muscle beef cuts. The process of cooking causes heat-induced denaturation of myoglobin (Mb), which is responsible for the characteristic dullbrown colour of cooked meat products. To ensure destruction of foodborne pathogens, including E. coli 0157:H7, beef should be cooked to an internal temperature of 71 °C (USDA, 1997). However, consumers generally do not use meat thermometers while cooking beef and often assume that a brown colour in the interior of beef indicates that the product has reached a temperature sufficient to inactivate foodborne pathogens. Unfortunately, the denaturation temperature for Mb is not constant in beef, and therefore, the relative dull-brown colour of cooked product interiors is not necessarily a reliable indicator that beef has been pasteurised (Bigner-George and Berry, 2000).