Pressurized liquid- and supercritical fluid extraction of crude and waste seeds of guarana (Paullinia cupana): Obtaining of bioactive compounds and mathematical modeling

In this work pressurized liquid- (PLE) and supercritical fluid extraction (SFE), combined with the enzymes cellulase and pectinase were applied to improve the recovery of phenolics and alkaloids from crude and waste seeds of guarana. The kinetic behavior of extractions was evaluated with the mathematical modeling of overall extraction curves (OECs) using a two straight-lines spline. The maximum recovery of catechin (50.59 g/100 g extract) and caffeine (46.19 g/100 extract) was raised in the PLE assisted with enzymes. The PLE assisted with enzymes also enhanced the total phenolic content and antioxidant potential, in comparison with the control samples and the 50% hydroethanolic solutions. The low recovery of target compounds by SFE is justified by the poor affinity of polar structure of catechins and methylxanthines in carbon dioxide. For most of the modeled OECs, the constant extraction rate time span was 40 min and the convective mass transfer mechanism was predominant. (C) 2019 Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.