It is increasingly recognized that the nutrient/phytochemical composition in foods can be optimized through agriculture and food technology. To put this strategy into practice, the compositional variation throughout the food chain has to be known. Additionally, natural variation in carotenoid composition must be distinguished from analytical variability. In endive, as well as lettuce, the carotenoid concentrations of the mature leaves were two to four times greater than those of the young leaves. In contrast, the younger leaves of New Zealand spinach had slightly higher carotenoid levels than the mature leaves. The carotenoid contents of marketed minimally processed endive and New Zealand spinach were significantly higher in the summer than in the winter, reflecting seasonal rather than processing effects. beta-Carotene, lutein, violaxanthin, and neoxanthin were reduced 18%, 19%,12% and 8%, respectively, in minimally processed endive during 5 days of storage at 7-9 degrees C. The corresponding losses in New Zealand spinach were 42%, 32%, 20% and 20%. (c) 2005 Elsevier Inc. All rights reserved.188845855