Avaliação do efeito de diferentes métodos de secagem, moagem e extração no óleo essencial de Baccharis articulata (Lam.) Pers.

Abstract

Essential oils (EOs) are aromatic oily liquids obtained from vegetable materials, which present bactericidal, antioxidant and antifungal properties. Nevertheless, the composition of the EOs can be modified during sample preparation steps, changing their quality and biological activity. The aim of this study was the evaluation of different sample preparation methods grinding, drying and atmosphere and extraction methods on the volume and composition of essential oil from Baccharis articulata (Lam) Pers., called as carqueja. For evaluation of grinding effect cryogenic, knives (with and without cooling) and balls mills were used. For drying four methods based on room drying, oven, freeze and microwave drying were used. For extraction the conventional hydrodistillation (HD) and solvent-free microwave extraction (SFME)were evaluated. The results showed that EO from milled plant with knives provided an EO with a profile similar to the EO from ungrounded plant, while the cryogenic mill resulted in smaller amount of EO due to the smaller particle size obtained leading to the glandular trichomes rupture and losses of EOs. Microwave drying resulted in an EO profile similar with that from fresh plant, the freeze drying provided smaller yield. The extraction time of 45 min with SFME provides yields comparable to those obtained after 4.5h by HD. The injection of O2 during extraction of the EO by microwave heating showed an EO with higher amounts of oxygenated compounds, higher antioxidant activity in comparison to extraction with injection of argon and synthetic air. This study showed that different sample preparation methods could impact the quality of EO.