Correlation of lycopene measured by HPLC with the L*, a* b* color readingsof a hydroponic tomato and the relationship of maturity with color and lycopene content

Tomatoes (Lycopersicon esculentum cv. Laura) were separated, according to t he ripening stage, by a sensory panel into seven groups, and color was meas ured on the tomato surface with a Minolta Chroma meter. The L*, a*, b*, hue , chroma, and lycopene content were plotted against the maturity stages of the tomatoes, and several good correlations were found. The a*/b* ratio and the lycopene content were the parameters that allowed six of seven maturit y groups in the tomato to be statistically distinguished. The lycopene cont ent, measured by HPLC, was also correlated with the color measurements, and the a*, a*/b*, and (a*/b*)(2) color factors produced the best regressions. An estimation of the lycopene content in tomatoes can be achieved by using a portable chroma meter, with a possible field usage application. Equation s to calculate the lycopene content of tomatoes based on the color readings are reported.