Myofibrillar protein gel properties are influenced by oxygen concentration in modified atmosphere packaged minced beef

- Minced beef was packaged in modified atmosphere with different oxygen concentrations.
- Packaging with oxygen induced strong and elastic myofibrillar proteins gels.
- Gels from meat stored without oxygen exhibited lower G′ and G″ values.
- Water loss of gels prepared from meat packaged with oxygen was higher.
- A mechanistic model involving protein cross-links is proposed.

Minced beef was stored for 8 days and myofibrillar protein (MP) was extracted to investigate the effect of oxygen concentration (0, 20, 40, 60, and 80%) in modified atmosphere packaging (MAP) on heat-induced gel properties. Compression force of gels was lower when prepared from beef packaged in 0% oxygen, intermediate in 20 to 60% oxygen and greater in 80% oxygen. Total water loss of gels prepared from beef packaged with oxygen (20-80%) was higher and rheology measurements presented higher G′ and G″ values. Additionally, gels from beef packaged without oxygen exhibited higher J (t) values during creep and recovery tests, demonstrating that oxygen exposure of meat during storage in MAP affect MP in such a way that heat-induced protein gels alter their characteristics. Generally, storage with oxygen in MAP resulted in stronger and more elastic MP gels, which was observed already at a relative low oxygen concentration of 20%.