Impact of Drying Methods on Bioactive Compounds and Functional Properties of Ilex guayusa Leaves

Abstract

CONDITION FOR PUBLICATION OF PROJECT. Ilex guayusa is a native Amazonian plant traditionally consumed as an infusion for its stimulant and antioxidant properties. This study examined the effects of five different drying techniques on the physicochemical and functional properties of guayusa leaves: freeze-drying, vacuum oven drying, solar drying, tray drying, and fluidized bed drying. Vacuum-oven preserved higher levels of L-theanine and theophylline (1594.56 mg/kg and 150.96 mg/kg, respectively) and produced the highest antioxidant activity and total phenolic content (64818.50 mol TE/100g and 8450.62 mg GAE/100g ss), while solar drying had the highest levels of caffeine and theobromine (30662.80 mg/ kg and 997.40 mg/kg). Freeze-drying, on the other hand, preserved the cellular matrix of the leaf, better retained the green color of the leaf, and promoted the stability of bioactive compounds during storage. Overall, these findings demonstrate that the drying process significantly affects the functional properties of guayusa, with vacuum-oven drying being the most effective technique for preserving quality in industrial applications, and freeze-drying being a suitable alternative when the stability of compounds during storage is prioritized, despite the need for prolonged infusion times.