A research note: Effect of citric acid and/or rosemary extract on color of an irradiated beef myoglobin model system

To determine the effect of antioxidants and irradiation on meat color, myoglobin (Mb) was extracted from beef hearts. Mb was treated with one of four antioxidants (control, citric acid [CA], rosemary extract [RE] or combination of citric acid and rosemary extract [CA/RE]) and irradiated at 0.00 (Control), 0.50, 0.75, 1.00, 1.25, 1.50, 1.75 and 2.00 kGy. Samples were then evaluated for thiobarbituric reactive substances, pH, L*, a* and b* values, hue angles, and Chroma. RE- and CA-containing samples had the highest postirradiation L*, a* and b* values, indicating they were lighter, redder and more yellow than controls. In terms of hue angles, all samples treated with antioxidants were much closer to the true red axis (a* = 0) of the CIE color space, both before and after irradiation, than was the control. The only color attribute affected by irradiation dose was L* value. Samples irradiated at 2.0 kGy were significantly lighter (L* = 5.27) than samples that had not been irradiated (L* = 1.28).