Extracto liofilizado de Ilex guayusa: potencial ingrediente para bebidas energizantes

The objective of this study is to produce and analyze a freeze-dried extract of Ilex guayusa, with a high caffeine concentration potentially used as ingredient in energy drinks. The caffeine extraction from dried leaves was done by ultrasounds, using water as solvent. The parameters considered were time, citric acid concentration, ultrasonic amplitude, solid/liquid ratio. Significant factors were optimized using a Box-Behnken response surface design. Physicochemical parameters and heavy metals were performed according to (Servicio Ecuatoriano de Normalización (INEN), 2013). The shelf life was determined by accelerated temperature tests. The results showed that time, citric acid concentrationand ultrasonic amplitude had significant effects on caffeine extraction, while the solid-liquid ratio was not significant. The optimum conditions for caffeine extraction were a time of 26.94 minutes, a citric acid concentration of 2.72 %, an ultrasonic amplitude of 68.29 % and caffeine concentration of 3.36 %. The physicochemical parameters of the freeze-dried product were: moisture of 1.2±0.1 %, total ash of 11.87±0.12 %, pH of 5.1±0.2, hot solubility of 17±1 s and cold solubility of 1.8±0.2 minutes. The levels of heavy metals found were zinc (19.16±0.04 mg/kg), copper (12.35±0.23mg/kg) and tin (8.64±0.17 mg/kg). The shelf life of the freeze-dried extract at 20 °C was 3.5 months. This paper provides valuable information for developing a freeze-dried product rich in caffeine.