Determinação dos teores de umidade e cinzas de amostras comerciais de guaraná utilizando métodos convencionais e análise térmica

Abstract

Paullinia cupana Kunth a vegetable popularly known as guarana, belongs to the Sapindaceas plant family and is predominant in the Amazon region. The low quality of this product can be attributed to the species and less noble varieties, harvest techniques and/or inadequate processing or, yet due to addition of substances that are not included in its natural composition. The main goal of this work was to evaluate from thermogravimetry (TG)/derivative thermogravimetry (DTG) and differential scanning calorimetry (DSC), the thermal behavior of powdered guarana samples in the Brazilian market in order to evaluate the thermal behavior of guarana powder samples commercialized in Brazil and to establish a comparative study between conventional and TG methods for humidity contents determination and ashes, In general, the samples did not present significant differences in the DSG curves profiles and TG/DTG. The thermogravimetry showed that it is possible to decrease the time of the analysis using less amount of sample and allowed to determine humidity and ashes contents. In relation to conventional method the errors of analysis inherent of the samples manipulation were decreased. The thermoanalytical techniques have shown potential applications in the determination of technological parameters, such as: quality control, toasting and adequate stock conditions.