Interpretive Summary: Impact of myoglobin oxygenation level on color stability of frozen beef steaks
By Anne Wallace
The likelihood that a consumer will purchase a beef product is strongly related to that product’s visual appeal. Bright red beef is perceived as fresh whereas discolored beef is perceived as less fresh and less desirable. Freezing also impacts color. Understanding how to optimally maintain the bright red color of beef is therefore very important to maintaining its consumer appeal.
Myoglobin is a muscle protein responsible for the red color of beef. In general, it is the oxidation of myoglobin that leads to discoloration. Yearly losses from meat discoloration are significant – up to a billion dollars. Therefore, research that aims to better understand how to maintain the bright red color of beef, like this recent Journal of Animal Science article, is valuable.
Choice strip loin steaks were used in this study. Researchers then evaluated how myoglobin oxygenation level impacted the color of frozen steaks. They also looked at the effects time, packaging type and aging had on color and quality. Steaks were vacuum packed and frozen for up to 6 months after being exposed to different myoglobin oxygenation levels. Categories of exposure were as follows: DeOxy (immediate packaging), Oxy (30 minutes oxygenated in air) and HiOxy (packaged for 24 hours in 80% oxygen). Oxygen permeable and oxygen impermeable packaging material was used.
HiOxy steaks had the brightest red color when compared to the other steaks, however, meat quality deteriorated after 4 months. Less aged steaks in oxygen permeable packaging performed the best. Overall, the longer the meat was frozen, the poorer its quality and color, regardless of oxygenation. The authors recommend the ideal conditions for frozen storage of up to 4 months is using HiOxy steaks aged for 4 days. More in depth studies looking at external factors impacting the color and quality of frozen steaks is justified.