Extraction of natural antioxidants from strawberry guava leaf by conventional and non-conventional techniques
Jaina Mara Pigosso Coelho, Gracielle Johann, Edson Antônio da Silva, Fernando Palú, Melissa Gurgel Adeodato Vieira
Abstract
Natural extracts of strawberry guava leaf were obtained using the following techniques: supercritical CO2 extraction (at 14, 17, and 20 MPa and 35, 45, and 55 °C); dynamic maceration with hexane solvent; Soxhlet extraction; ultrasound-assisted extraction (at 40, 50, and 60 °C; 100, 300, and 500 W; 1:10, 15, and 20 g mL−1), and supercritical extraction followed by ultrasound. Yield results were 3.59% for Soxhlet extraction, 2.68% for ultrasound-assisted extraction, 1.46% for ultrasound re-extraction after supercritical extraction, 0.98% for dynamic maceration, and 0.86% for supercritical CO2 extraction. Natural extracts of strawberry guava leaves obtained via supercritical extraction were found to be rich in eudesmol, squalene, and vitamin E, in 11.03, 19.44, and 53.42% percentages, respectively. They also exhibited high antioxidant activity, 26.15 μg mL−1. This result was directly related to the α-tocopherol present in vitamin E.