Rendimento de cafeína extraída do epicarpo lenhoso de sementes de guaraná (Paullinia cupana H.B.K. var. sorbilis) sob diferentes condições de extração

Abstract

Paullinia cupana H.B.K, var. sorbilis, known as guarana is a typical Brazilian plant, being intense and mainly cultivated in the Amazon region. It is used in folk medicine as a stimulant of brain functions, but several other uses have already been reported as: stimulating, antithermal, antineuralgic effect (BETENDORF, 1909), anti-flu action (DEWICK, 1998), aphrodisiac, analgesic and antidiarrheal (HENMAN, 1982; DUKE, 1985; BENOWITZ, 1990). It is a raw material widely used in Brazil, used in the production of carbonated soft drinks that makes guarana one of the most consumed beverages in the world (GOODMAN & GILMAN, 1996), (SOUSA, 1991), as well as syrups, tonic beverage, crafts, caffeine source, and cosmetic preparations, in the treatment of oily skin and cellulite. The fruit stands out for its remarkable caffeine content, which is called trimethylxanthene and is part of a group of compounds classified as true alkaloids (purinic alkaloids) that can be extracted using toxic and high-cost substances such as acetone, methanol, chloroform and dichloromethane. Traditionally, guarana extract is obtained in the beverage industry through infusion in hydroalcoholic solution, which causes the drag of other substances such as tanse acids, which negatively interfere in the quality of the extracts obtained. The general objective of this work was to extract caffeine from the woody epicarp of guarana seeds (bearing), a byproduct of guarana powder production, low cost and high alkali concentration (CHAAR, 1990). For this, six forms of extractive process comprising well drinking water at 100ºC pH 5.1 and 7.5 were used, using a soxhlet system; hydroalcoholic mixture, using well drinking water and commercial alcohol at 97ºGL at concentrations of (40:60% v ̸ v), pH 5.3 and 7.5 and (60:40% v ̸ v), pH 5.6 and 7.5. Sodium hydroxide was used to obtain pH 7.5. Extractions using hydroalcoholic mixture were performed at room temperature. All samples were for a variable period of 1, 3, 6 and 12 hours and were filtered using buchner funnel and qualitative filter paper in vacuum system. The samples were stored in amber glass jar at room temperature. The filtrates were cleaned using saturated solution of lead acetate and baking soda. Caffeine was determined by HPLC.