GUARANA, the plant Paullinia Cupana (or P. sorbilis) of the natural order Sapindaceae, indigenous to the north and west of Brazil. It has a smooth erect stem ; large pinnate alternate leaves with five oblong-oval leaflets; narrow panicles of short-stalked flowers; and ovoid fruit about as large as a grape, and containing usually one seed shaped like a minute horse-chestnut. Guarana, guarana bread, or Brazilian cocoa, is prepared from the seeds as follows. In October and November, when ripe, the seeds are sun dried, to admit of the ready removal by hand of the white aril; ground in a stone mortar or deep dish or hard sandstone; the powder, moistened with water, is made into a paste with a certain proportion of whole or broken seeds, and worked up usually into rolls 5-8in. in length, and 12-16 oz. in weight. After drying by heat, the guarana is packed between broad leaves in sacks or baskets. Thus prepared, it is of extreme hardness, has a brown hue, a bitter astringent taste, and an odour faintly resembling that of roasted coffee. An inferior kind is manufactured by ad mixture of cocoa or cassava. Rasped or grated into sugar and water, guarana forms a popular beverage in South America.
The properties of guarana as a nervous stimulant and restor ative are due to the presence of caffeine or theine. In addition, guarana yields the glucoside saponin, with tannin, starch, gum, three volatile oils and an acrid green fixed oil.