Chá verde brasileiro (Camellia sinensis var assamica): Efeitos do tempo de infusão, acondicionamento da erva e forma de preparo sobre a eficiência de extração dos bioativos e sobre a estabilidade da bebida

Abstract

Studies on the Brazilian green tea (Camellia sinensis var assamica) are still scarce when compared with the great number of investigations conducted on the green tea produced in other countries. The purposes of the present study were to evaluate the effects of infusion time, mode of packaging (tea in bulk or in tea bags) and preparation on the extraction of bioactive compounds from the Brazilian green tea and on the stability of the beverage. The evaluated parameters were: the amounts of soluble solutes and phenolic compounds that were extracted as well as the antioxidant properties of the beverage using the DPPH method (2,2-diphenyl-1-picrylhydrazyl radicals). The results revealed that the use of the herb in bulk with 5 minutes stirring was the most adequate condition for the extraction of bioactive compounds from the green tea. Increases in the volume of the preparation without changes in the herb/water ratio increased the efficiency of the bioactive compounds extraction due to the fact that cooling a large volume of water is delayed in comparison to cooling smaller volumes. It can be said that the obtained beverages were stable for 24 hour at room temperature and in the refrigerator since no decrease in the antioxidant properties and significant changes in the contents of the major bioactive coumpounds, namely epigallocatechin gallate, epicatechin, catechin, and caffeine were detected.