124 Color Changes of Leaf Lettuce during Postharvest Storage

Abstract

Leaf lettuce is a major and widely cultivated vegetable crop. Leaf lettuce is preferred for wrapping food, like rice or meat, and is much more popular than head lettuce in Korea. Color change and water loss condition are most important factor for buying decision as external quality. This paper studied color change during storage at 20 and 4 °C, 60% RH. The color analysis of adaxial surface of leaf lettuce during shelf-life storage condition showed that Hunter L and a value increased slightly after 5 days of harvest, while delta-Eab started increasing after 3 days of postharvest. Chlorophyll content decreased by half during the first 5 days after harvest. These color changes, however, could not explain the changes in leaf chlorophyll content while the color intensity of G (green) component in RGB analysis showed a close relationship with leaf chlorophyll content changes. Visual quality score showed that lettuce may kept its marketability up to 5 days after harvest. But, in refrigerator (4°C, 60% RH, cold chain system) storage condition. Leaf color is about three times longer than shelf-life. Theses results of each evaluation methods consistently demonstrated that leaf lettuce may keep its marketability up to 5 days in a distribution market without color quality damage.