Optimal Drying Conditions of Leaves and Variation of Caffeine Content in Guayusa in the Ecuadorian Amazonia.

Optimal Drying Conditions of Leaves and Variation of Caffeine Content in Guayusa in the Ecuadorian Amazonia M. Rocha1, L. Cobos1, P. Crespo1, S. Balarezo2,C.Martinez2, P. Marañón3, G. García1* Guayusa (Ilex guayusa) is a native wild tree from the Ecuadorian Amazonia. Traditionally, its air-dried leaves are consumed in infusion and credited with healing and stimulating properties because of the phytochemical compounds. It is a neglected crop. Post-harvesting technologies and knowledge about bioactive metabolites (BM) such as caffeine content do not exist. The aim of this study was to determine the optimal drying conditions of leaves and the variation in caffeine content from a plantation located in the north western of Ecuador. Leaves from plants randomly selected were harvested, bulked. Three separate groups were formed and dried for 4 hours at three temperatures (40°C, 60°C, 80°C) and no differences on caffeine content was observed. Plantation was stratified according to the slope in: high slope (HS), medium slope (MS) and low slope (LS). Twenty four individuals were randomly selected within each slope. Leaves of 72 plants were collected, dried, grinded and analyzed, separately. Caffeine quantification was done by High Performance Liquid Chromatography (HPLC). Analysis of variance detected highly significant differences between slopes. The highest mean of 2.99 mg. 100 mg-1 was observed in the MS, followed by the 2.64 mg-1.100 mg-1 leaf observed in LS, and the lowest mean of 2.22 mg. 100 mg-1 was presented in HS. The average caffeine content was 2.62 mg. 100 mg-1, and variation ranged from 0.98 mg. 100 mg-1 to 5.64 mg. 100 mg-1. Key words: Caffeine, drying conditions, guayusa. 1 Universidad Central del Ecuador. Facultad de Ciencias Agrícolas. *Corresponding autor gmgarcia@uce.edu.ec 2 Laboratorios Quimicas Ariston 3 Huasquilla Lodge