Lipids, tocopherols, and carotenoids in leaves of amaranth and quinoa cultivars and a new approach to overall evaluation of nutritional quality traits.

Abstract

Composition of lipophilic phytochemicals including fatty acids, tocopherols, and carotenoids in leaves of 6 quinoa and 14 amaranth cultivars was analyzed. The oil yields in quinoa and amaranth leaves were only 2.72-4.18%, which contained mainly essential fatty acids and had a highly favorable ω-3/ω-6 ratio (2.28-3.89). Pro-vitamin A carotenoids, mainly α- and β-carotenes, and xanthophylls, predominantly lutein and violaxanthin, were found in all samples. The primary tocopherol isomers present in both quinoa and amaranth leaves were α- and β-tocopherols. Added to the discussion on the lipophilic nutrients was the normalization of ω-3/ω-6 ratio, α-tocopherol equivalents, and carotenoids, in an attempt to establish a novel system for evaluation of the overall quality attributes of lipophilic nutrients (NQ value). The NQ value, but not the individual components, was highly correlated with all the antioxidant activities, supporting the ranking order of the potential nutritional quality of quinoa and amaranth leaves based on this new method.