Effect Of Modified Atmosphere Packaging On Color Stability And Potential Mechanisms In Maintaining Color Stability Of Different Bovine Muscles

Beef color plays a critical role in determining consumers’ purchasing decisions because meat color is frequently used as an indicator of freshness and wholesomeness. Modified atmosphere packaging is used to maintain the attractive red color of beef and can extend the shelf life of beef. Each muscle has the unique fiber type and metabolic function, so the color stability of each muscle is different. Differences in color stability among muscles have been attributed to metmyoglobin reducing activity (MRA) and NADH concentration. Muscle effects on color stability are dependent on packaging type. Packaging can affect the metmyoglobin reducing activity of bovine muscles.Some papers reported that CO-MAP could significantly increase color stability of muscles. The reason that CO-MAP could enhance color stability has not been explored. And no information has been provided about the MRA under the CO-MAP condition. Additionally, the variable color stability of CO-packaged beef steaks from different muscles after opening the packages is not clear. Little information is available about the effects of different packaging types especially CO-MAP and HiOx-MAP on NADH concentration. The objectives of this study were to compare the effects of CO-MAP and HiOx-MAP on color stability and on the rate of red color loss of three muscles and to explore the potential mechanisms for enhanced color stability by CO-MAP, and especially, to investigate the relationships between the packaging methods and the MRA and NADH concentration.The main results were as follows:Compared with high oxygen and vacuum packaging, CO-MAP significantly increased color stability of longissimus lumborum, psoas major and longissimus thoracis during storage, especially for PM. The PM and LT were more red than LL in CO-MAP, whereas PM had lowest redness in HiOx-MAP. CO-MAP significantly increased a*value of steaks compared with high oxygen and vacuum packaging.The pH value was not affected by the packaging, while the content of MetMb in CO-MAP was significantly lower than in HiOx-MAP. Compared with HiOx-MAP, CO-MAP significantly increased MRA of steaks, and the metmyoglobin reducing activity in CO-MAP remained relatively stable during storage. The steaks in CO-MAP had a higher TRA than those in HiOx-MAP. That might be the reason why CO-MAP maintained red color stability of steaks during storage. Packaging had no effect on NADH concentration during storage.The color of steaks in CO-MAP deteriorates relatively slowly upon opening the packages, compared to steaks in HiOx-MAP, indicating that CO-MAP significantly increased color stability of beef. The PM steaks in CO-MAP had the higher color stability and a*value even after the packages were opened, but PM steaks in HiOx-MAP had the lowest red color stability after opening of packages. The content of MetMb in CO-MAP significantly decreased from day0to day1and then increased from day1to day3while the MetMb contents increased in high oxygen and vacuum packaging during display time after packages were opened. The steaks in HiOx-MAP had the higher contents of MetMb than those in other packaging during display.