Evaluation of 107 legumes for renewable sources of energy

Abstract

One hundred and seven species of randomly-collected Leguminosae were evaluated for their potential as energy-producing crops. Whole plants, excluding roots, were chemically analyzed, and 11 species were identified as the more promising for future considerations based on a numerical rating system developed at this Center. Botanical, fiber, and protein characteristics of the more promising species that had ratings of less than 11 were considered excellent. Other characteristics, including contents of oil (1.7–3.2%; dry, ash-free, sample basis), polyphenol (5.4–16.5%), and hydrocarbon (0.3–0.6% for 10 species and 2.6% for one), were generally lower than those of promising species in other families previously analyzed. Of the 11 species, one contained principally rubber (polyisoprene) in the hydrocarbon fraction and 7 contained principally wax. Hydrocarbon fractions of 3 species with less than 0.4% were not examined. The oils of species with at least 3.0% oil were examined by thin layer chromatography (TLC) to determine classes of components and were given a saponification treatment to determine yields of unsaponifiable matter and fatty acids. The oil of one species was quantitatively analyzed for classes of compounds by TLC-flame ionization detection. Selected species with ratings greater than 10 are briefly discussed.