Extração do óleo da borra de café, compostos bioativos e sua aplicação em máscaras faciais do tipo peel-off

Abstract

Coffee is the most consumed beverage in the world and the second most commercialized commodity, generating numerous residues from its processing and consumption. Coffee grounds are the most expressive residue of this production, being highly appreciated due to its numerous applications in industry and research, with the oil obtained by extraction with organic solvents being its most valuable component. In this work, studies were carried out with coffee grounds obtained from two different species (Coffea arabica and Coffea canephora) from the states of São Paulo and Minas Gerais. The coffee grounds were washed and oven dried. The oil was extracted from the dried coffee grounds through a Soxhlet extractor using ethanol and n-hexane solvents and the water obtained from washing the coffee grounds was lyophilized. The yields obtained from the oil extraction were 63.83g for the sample of Aviação arabica coffee extracted with ethanol to 5.75g for the Conilon sample extracted with hexane. The acid value of the samples ranged from 4.04 mg KOH/g of oil for the 100% Arabica A1 sample to 11.96 mg of KOH/g of oil for the 100% Conilon sample. The fatty acid profile of coffee grounds oil was analyzed using three methods involving acid catalysis (BF3/MeOH and CH3OH/H2SO4) and basic catalysis (MeONa/MeOH). The main fatty acids identified were palmitic acid (18.50-52.59%), linoleic acid (0-38.18%), oleic acid (2.87-17.69%) and stearic acid (5.49-17.90 %), obtained through gas chromatography with flame ionization detector (GC-DIC) and gas chromatography coupled with mass spectrometry (GC-MS). There were no significant differences in the lipid profile of the samples, regardless of the solvent used, as well as the species originating from the coffee grounds evaluated (Coffea arabica and Coffea canephora). The bioactive compounds (caffeine and chlorogenic acid) present in the lyophilized material and the extracted oil were applied in a peel off face mask. The lyophilized material obtained total phenol content ranging from 6.00 ± 0.65 to 7.79 ± 0.58 mg GAE/100mg of sample, and the sample that presented the highest antioxidant capacity was Conilon. The degree of swelling followed the profile of release of bioactive compounds present in the film and the highest gel fraction was presented by the conillon sample without washing. The films remained with their surface and integrity preserved and the presence of turbidity and color in the solution indicated the presence of bioactive compounds in suspension. The film applied to the skin presented a pleasant touch, ease of spreading and removal from the skin and a pleasant odor, being ideal for use. The oil release test of the “peel off” mask showed that the type of coffee grounds, the type of solvent and the washing of the grounds significantly interfere with the release of fatty acids, at 232nm the Arabica coffee grounds oil obtained the highest release for linoleic acid against Conilon, while at 210nm for palmitic acid the release was greater for Conilon sludge oil. The study of release kinetics obtained for the bioactive compounds of coffee grounds, show that both the oil, caffeine and chlorogenic acid present in the lyophilized material, have potential for application in cosmetic products, and can be used as actives in face masks.