EVALUATION OF INFLUENCE OF SIZE PARTICULE AND DIFFERENT EXTRACTION METHODS IN OBTAINING EXTRACTS FROM COFFEE HUSKS WITH HIGH ANTIOXIDANT ACTIVITY

Coffee is an important crop in Brazil and in the world. However, due to this intense activity, tons of waste are generated from its processing, such as bark, pulp and straw. Agroindustrial residues are rich in phytochemicals, which are substances belonging to different classes and are known for their beneficial health effects, mainly by combating reactive oxygen species (ROS). Many variables such as extraction method, time, particle size, temperature, agitation influence the concentration of bioactive compounds present in the extracts. The objective of this work was the evaluation of 9 extraction approaches using classic emerging techniques such as extraction using ethanol and acetone solvents, as well as techniques such as the use of ultrasound, autoclave and hydrolytic enzymes and 2 two different particle sizes (912 µm and >295 µm). In the obtained extracts were assayed total phenolic compounds, antioxidant activity by DPPH, FRAP and ABTS and the results were evaluated using the Randomized Block Design methodology. The results to phenolic compounds showed that the best approach was the extraction assisted by the enzyme Viscozyme used in the two concentrations 0.1% (24.2 mg/g) and 0.5% (22.7 mg/g). The concentrations of phenolic compounds obtained with flour with smaller granulometry were higher for all extraction strategies, except for the classic extraction using acetone as solvent. This was confirmed by the significant block effect evidenced by the DBC (p-value < 0.05). To antioxidant activity by DPPH, FRAP and ABTS, the best results were thermal extraction (autoclave during 15 minutes) (343,5 µmoL TE/g ), extraction assisted by the enzyme Viscozyme L 0,1 % (77,6 µmoL TE/g) and were thermal extraction (autoclave during 15 minutes) 391,2 µmoL TE/g, respectivily. The results showed the relevance of granulometry in extraction process and the use of methods that are less aggressive to environment are efficient to obtain antioxidant compounds.