OPTIMIZATION OF ULTRASOUND-ASSISTED EXTRACTION OF POLYPHENOLS FROM COFFEE (COFFEA ARABICA L.) SHELL AND PULP USING RESPONSE SURFACE METHODOLOGY

Abstract

This work aimed to optimize the radiation amplitude (%), the ethanol concentration (%), and the extraction time (min) to achieve a high content of polyphenolic compounds. The Box-Wilson design optimized the extraction by applying the face-centered compound and the total phenolic compounds as response variables. As a result, an adequate quadratic model was obtained that was adequate, with R2 = 0.989. The optimal conditions were radiation amplitude of 95%, an ethanol concentration of 55%, and an extraction time of 9 min. The optimized coffee residue extract (Coffea Arabica L.) showed a total phenolic compound of 41.16 (± 0.020) mg GAE (gallic acid equivalent)/g, 2,2-diphenyl-1-picrylhydrazyl-hydrate (DPPH) antioxidant activity of 57.02 (± 0.040) mmol Trolox equivalent (TE), and Trolox equivalent antioxidant capacity (TEAC) antioxidant capacity of 46.86 (±0.020) mmol Trolox equivalent. It was concluded that the methodology applied makes it possible to find models closely related to the expected values indicating their suitability.