BACKGROUND: Consumption of pulse crops, including field pea, is considered effective for a healthy diet. Hulls (seed coats) play an important role for protection of the cotyledon and embryo, but also as mediating positive effects on health outcomes. The biochemical attributes of field pea hulls were thus assessed to determine the occurrence of specific phytochemicals and their genotypic variability.
RESULTS: Sequestered bioproducts in mature hulls predominantly consisted of trans-lutein and chlorophylls a and b. Trace amounts of other carotenoid and pheophytin metabolites were identified. In developing hulls, violaxanthin, neoxanthin, lutein, zeaxanthin, chlorophylls a and b and β-carotene were detected. Genotypic differences in the accumulation of lutein and chlorophylls a and b were observed over years and locations. Polyphenolics and hydroxybenzoic acids were detected in the ‘dun’ and ‘maple’ field pea types—the only genotypes to have pigmented hulls. Unextractable patches of condensed tannin influenced the visual uniformity of the maple and dun genotypes, CDC Rocket and CDC Dundurn.
CONCLUSIONS: Within the yellow and green market classes, carotenoid and chlorophyll accumulation was consistent. Green cotyledon varieties sequestered higher concentrations of lutein than the yellow cotyledon varieties. Maple and dun types were more variable, reflective of different selection criteria. The occurrence of flavonoid-related compounds was correlated only with pigmented seed coat genotypes. The dietary potential of the chlorophylls and carotenoids that accumulated in the hulls split from the green and yellow field pea types is discussed as a value-added prospect in food supplements. © 2012 Society of Chemical Industry