December 2/Journal of Technology & Science -- According to a study from Ludhiana, India, "Broccoli was stored under modified atmosphere packaging (MAP) at 20 degrees C in perforated and unsealed polypropylene film packages for a storage period of 10 days to evaluate the effect of modified atmospheres on the chromatic changes. At the end of storage, MAP resulted in differential changes in the original green color of broccoli under different packaging treatments."
"Instead of conventional CIELAB color space system utilizing only L*, a* and b* values, the chromatic changes were analyzed as per L*C*h* color space system using lightness, chroma, and hue angle values to evaluate the final hue (color) along with its associated attributes. On the 10th day of storage, broccoli samples kept under different modified atmospheres were observed to be yellow-green only for four holes, but between yellow-green and yellow for 8-, 12-, and 16-hole treatments, respectively. Further, the saturation of final hue attained under different packaging treatments kept on increasing in the order of 4, 8, 12, and 16 holes. On the other hand, broccoli kept in air in unsealed packages turned orange-yellow with higher saturation as compared with MAP samples. The direction of color difference for different treatments with respect to fresh broccoli samples was observed as light and the degree of color difference indicated that 4- and 8-hole treatments were only slight and medium light, respectively. The 4-hole treatment had best color retention, as it had slightly saturated yellow-green hue, which was only slightly lighter than the fresh broccoli," wrote R. Rai and colleagues.
The researchers concluded, "Also, the results of sensory and visual analysis confirmed the results obtained from L*C*h* color space diagram and indicated that the modified atmosphere (6.1% O-2 and 9% CO2) generated inside the perforated film packages having 4 macro-holes was the most suitable in maintaining the chromatic quality of the broccoli heads."
Rai and colleagues published the results of their research in Food Science and Technology International ("Chromatic Changes in Broccoli (Brassica oleracea italica) under Modified Atmospheres in Perforated Film Packages." Food Science and Technology International, 2009;15(4):387-395).
For additional information, contact R. Rai, Cent. Institute Post Harvest Engineering & Technology, Punjab Agriculture University Campus, Ludhiana, Punjab, India.
From the December 7, 2009, Prepared Foods E-dition