Estudo da extração de compostos bioativos do guara ná com adição de ácido cítrico

Abstract

Guarana contains more caffeine than any other plants in the Amazon region. The seeds of guarana contain in addition to alkaloid a mixture of polyphenol, which is associated with antioxidante activity and health benefits on human body. It has been shown interest in deve loping plant extract based products, making it necessary to study extraction techniques that are not only profitable, but it is also enviornmentally friendly and efficient. Based on this, the new method of hydroalcoholic extraction in shaker incubator with addition of citric acid was developed. A fractionated factorial design 25-2 was performed in order to investigate folowing variables: temperature (30 – 60 ºC), time (4 – 10 h), hydroalcoholic solution concentration (HSC, 30 – 80 %), agitation (56 -168 rpm) and citric acid presence (0 – 0,1 g). Caffeine yields and total phenolic compounds (TPC) were response variables. The statistical analysis was conducted using the Statistica software (version 10) (p = 0,05). For caffeine extraction res ponse, it was obtained yelds between 1,14 and 2,56 %. The variables with greater statistical significance were agitation, HSC and time. Citric acid presented positive interaction effect with temperature and time, although it was not significant alone. For TPC, it was reached yelds between 9,97% and 14,73%. No significant effect was noticed. Curvature effect was the most important effect in this case, which suggets that a quadratic model would describe better this process. In addition, citric acid was the most importante isolated effect, favoring TPC yields, in addition to interact with time and temperature. The study showed that the optimum conditions obtained through desirability function are: TPC = 55%; T = 60 ºC; t = 10 h; Agita tion = 168 rpm; citric acid= 1 g. Thefore, a new approach for guaraná extraction was able to improve yields of caffeine and polyphenols under presence of acid additive.