DISTRIBUTION PROFILES OF TOCOPHEROLS AND FATTY ACIDS OF PHOSPHOLIPIDS IN ADZUKI BEANS (VIGNA ANGULARIS)

ABSTRACT

Extracted lipids from adzuki beans (Vigna angularis) were determined by high-performance liquid chromatography for tocopherol homologues. Fatty acid distributions of triacylglycerols (TAGs) and major phospholipids (PLs) were analyzed by gas chromatography, and their tocopherol contents were determined. δ-Tocopherol was present in highest concentration (77.6%), and γ-tocopherol in small amounts (22.4%). However, α- and β-tocopherols were not detected in adzuki beans. The major lipid components were PL (63.5%) and TAG (27.1%), while other components were also present in minor proportions (0.2–5.1%). The major PL components were phosphatidylcholine (45.3%), phosphatidylethanolamine (25.8%) and phosphatidylinositol (21.5%). The positional distribution of fatty acids in these PLs was evident in the beans: unsaturated fatty acids were predominantly located in the sn-2 position, while saturated fatty acids primary occupied the sn-1 position in these lipids.

PRACTICAL APPLICATIONS

This study describes the characteristics of lipid components, positional distribution of fatty acids in the major phospholipids as well as the tocopherol profiles of adzuki beans. These results were not similar to the positional fatty acid distributions in the oilseeds such as peanuts, soybeans and sesame seeds. The data obtained would be useful to both consumers and producers for manufacturing traditional adzuki confectionaries (wagashi) in Japan and elsewhere.