2016 Volume 17 Issue 4 Pages 107-113
A method to objectively evaluate the external quality of broccoli heads using a computer vision system (CVS), a type of digital camera, was proposed. The CVS was effective in calculating the spatial distribution of color space values of broccoli heads. Value of –a*/b* (chromaticity of Commission Internationale de l’Éclairage) was effective in evaluating the concentration of chlorophyll a. An –a*/b* value greater than 0.94 indicated fresh buds that remained green. Conversely, the value of a* was effective in evaluating the existence of anthocyanins that damage the external quality of the broccoli head. Buds with low concentrations of anthocyanin had an a* value less than -12. These two thresholds were used for visualizing high-quality buds with high concentrations of chlorophyll a and low concentrations of anthocyanin. The proportion of high-quality buds of typical heads that included low or high concentrations of anthocyanin reduced from 39% or 22% to 15% or 5.4% during 5 d storage. The proportion of high-quality buds of typical heads with low anthocyanin concentrations was usually higher than those with high anthocyanin concentrations. These results suggest that the proposed method using the CVS is suitable for objectively evaluating the external quality of broccoli heads and selecting high-quality heads.
