Total color change (ΔE∗) is a poor estimator of total carotenoids lost during post-harvest storage of biofortified maize grains

Provitamin A biofortified maize is promoted in developing country to curb vitamin A deficiency. To determine the provitamin A carotenoid content of fresh and stored biofortified maize requires analytical techniques that are affordable by the targeted population. In this study color parameters (L∗, a∗, b∗) individually or in combination were used to estimate carotenoid content in high carotenoid biofortified maize. There was an increase in L∗ value with storage indicating grains were becoming lighter while a∗ and b∗ values did not change significantly. Almost all storage bags induced total color change (ΔE∗) greater than 2 which is perceivable by consumers as a deviation from original quality. The coefficient of determination (R(2)) between carotenoid content and color parameters were high and significant for most color parameters suggesting that they could be used to estimate carotenoid content in biofortified maize. While change of color is indicative of carotenoid degradation, our study found that ΔE∗ is a poor estimator of carotenoids lost during post-harvest storage of biofortified maize. Hue (h∗), L∗ and a∗ gave consistently and significantly higher R(2) (p < 0.05) for almost all carotenoids analyzed suggesting that they could be used to generate predictive models for estimating carotenoid content in stored biofortified maize.