270: Phenolics From Murtilla Pomace: Enzyme-Assisted Extraction and Antioxidant Properties

Introduction

The production of fruit juice yields high amounts of pomace, which has a high content of phenolic compounds. Some native Chilean berries, including murtilla, have a high phenolic content. However, the enzyme-assisted extraction of phenolics from this by-product has not been addressed. Therefore, this study focused on the extraction and characterization of phenolic compounds and the antioxidant properties from the residue generated after murtilla juice production by using enzymatic treatment focusing on Viscozyme.

Methods

The fruits were processed to obtain murtilla juice, and the residue was lyophilized, defatted, and subjected to various extraction techniques using enzymatic hydrolysis (2% Viscozyme in acetate buffer pH 4 for 16 h at 37°C, 10 mL of enzyme per g of residue). The extracts were analyzed for total phenolics and flavonoids, phenolic quantification by LC-MS/MS, and antioxidant activity using different methods (FRAP, ORAC, DPPH, and ABTS).

Results

The enzymatic pretreatment with Viscozyme increased the total phenolic content by up to 54% andantioxidant capacity measured by FRAP by 36% compared to the control. The ratio of soluble to insoluble phenolics was 0.78, indicating that some insoluble phenolics remained unreleased by enzymatic hydrolysis. Identification by UPLC-MS/MS was performed and 7 phenolic acids and 7 flavonoids were identified. These are gallic acid, syringic acid, vanillic acid, 3,4-dihydroxybenzoic acid, caffeic acid, p-coumaric acid, ferulic acid, quercetin, miricetin, rutin, quercitrin, catechin, epicatechin, and taxifolin. 12 out of 14 compounds increased in enzyme-treated extracts in reference to the control in the soluble phenolics fraction. The main compounds identified were gallic acid, quercetin, rutin, and quercitrin in this fraction.

Significance

The present study demonstrates that enzyme-assisted extraction may be an environmentally friendly strategy in the recovery of natural antioxidants from murtilla pomace.

Authors: Vicente Gregorio Valenzuela Bass, Gabriela Valenzuela-Barra, Miguel Angel Rincón-Cervera, Raquel Bridi, Adriano Costa de Camargo