tonka bean tŏng´kə [key], black-skinned, aromatic, almondlike single seed from the pod of any tall leguminous tree of the genus Dipteryx in the family Leguminosae ( pulse family) of tropical South America. It contains coumarin, a fermented substance that has a vanillalike aroma and is used as a vanilla substitute and in the manufacture of perfumes, sachets, soaps, tobacco, and food. Natural coumarin has been almost completely replaced by a synthetic product. The name of the bean also appears as tonqua bean and tonquin bean. Plants producing tonka beans are classified in the division Magnoliophyta , class Magnoliopsida, order Rosales, family Leguminosae.
The Columbia Electronic Encyclopedia, 6th ed. Copyright © 2012, Columbia University Press. All rights reserved.
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