Cellulase-assisted extraction followed by pressurized liquid extraction for enhanced recovery of phenolic compounds from ‘BRS Violeta’ grape pomace
Tatiane de Oliveira Xavier Machado, Helena de Almeida Cerqueira Kodel, Fagne Alves dos Santos, Marcos dos Santos Lima, Anabela S. G. Costa, M. Beatriz P.P. Oliveira, Cláudio Dariva, Charles dos Santos Estevam, Faezeh Fathi, Eliana B. Souto
Abstract
• Enzymatic treatment of grape pomace (GP) (BRS Violeta) with cellulases as a first-step extraction prepares the matrix to PLE, making compounds easier to be released. • Enzymatic treatment helps the release of gallic acid, syringic acid, cis -resveratrol, procyanidin B1, procyanidin B2, epicatechin, epicatechin gallate, myricetin, cyanidin 3,5-diglucoside. • Myricetin is the most influenced compound by the cellulase activity on GP. • Extracts obtained by PLE after enzymatic treatment have a greater potential for medical and pharmaceutical applications. The extraction of phenolics from grape pomace (GP) is still a challenging process as part of compounds may be bound to macromolecules in the plant cell wall. Herein, the combination of pressurized liquid extraction (PLE) and enzyme-assisted extraction (EAE) to recover phenolic compounds was evaluated for the first time in GP (BRS Violeta). Results of the spectrometric analysis showed a reduction in the total phenolic and flavonoid contents, as well as in the antioxidant activity of the extracts, when cellulases were applied. Nevertheless, HPLC analyses demonstrated a significant influence of EAE on the recovery of specific compounds, especially when it was applied prior to PLE. Myricetin, trans -caftaric acid, gallic acid, p-coumaric acid, epicatechin, epicatechin gallate, and procyanidin B1 and B2 were predominantly present in that treatment. Myricetin concentration was improved 10.9-fold compared to the extraction performed solely by PLE. The extraction method presented may be an alternative to obtaining extracts more concentrated in certain phenolic compounds and, thus, more prone to food and pharmaceutical applications.