Chemical Composition of Abrus precatorius L. Seeds

Abstract

Aims: A. precatorius seed powder is traditionally used in Ayurveda, Siddha and Unani medicine. The objective of present work is to describe the oil, starch, protein, polyphenol and mineral composition of A. precatorius seeds. Methodology: Legumes from A. precatorius were collected, and seeds were manually separated. Dried seeds in powder form were employed for the various analyses: solvent extraction was used for elucidation of the oil percentage value; starch content was determined by the enzymatic method; total polyphenol and flavonoid contents were spectrophotometrically analyzed using Folin-Ciocalteu and aluminum chloride as the color developing reagents, respectively; and X-ray fluorescence (XRF) was used for the mineral contents assessment. Results: The seed kernel consisted of stored oil (3.2%), protein (92.0%) and starch (4.8%). The total polyphenol and flavonoid contents were 24710 and 2520 mg/kg (dw). A remarkably high content of polyphenols was observed in the seed coat and the seed pod. P, S and (mainly) K nutrients were hyper-accumulated in the seed kernel. The seeds showed a glass transition at -21°C, two endothermic peaks at 109°C (dehydration and protein unfolding) and at 209°C, and a calorific value (~406 kcal/100 g dw) that exceeded those of Pisum sativum L., Lens culinaris Medik. and other common pulses. Conclusions: The seed kernel from A. precatorius was mainly composed of stored protein, with low oil and starch contents. High contents of polyphenols, K, Mg, Ca and Fe were found in the seeds. Heavy metals were below the safety limits established for human consumption.