397: Optimization of Pulsed Electric Field Extraction of Red Beetroot Bioactive Compounds: A Clean Label Solution for Antioxidant and Colorant Applications in the Food Industry

Introduction

Red beetroot is commercialized in large quantities, often resulting in significant waste due to small or malformed pieces that are not accepted by consumers. This creates an opportunity to utilize such co-products as a valuable matrix for extracting bioactive compounds. The extraction of these compounds yields a natural, plant-based extract with high antioxidant properties. The aim of this study was to optimize the extraction of beetroot bioactive compounds with antioxidant capacity using the innovative pulsed electric field (PEF) technology.

Methods

The optimization of extraction using PEF was performed through a Box-Behnken experimental design (3 factors and 3 levels) with 15 experimental runs, where the independent factors were the solvent-to-solid ratio, pulse number, and voltage, set at levels of 60, 80, and 100; 50, 100, and 150; and 6000, 8000, and 10000 V, respectively. The starting material consisted of dried beetroot powder, with water used as the solvent. Total phenol content (TPC) and antioxidant capacity (through the 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2-2’-azino-di-(3-ethylbenzthiazoline sulfonate) (ABTS), ferric reducing antioxidant power (FRAP), and oxygen radical absorbance capacity (ORAC) methods) were evaluated, which were treated as dependent variables. Response surface methodology was applied to identify the optimal levels of the independent variables that maximize the dependent responses.

Results

The statistical analysis performed using the Box-Behnken design revealed that only the solvent-to-liquid ratio exerted a significant effect on the extraction of bioactive compounds from beetroot. Specifically, this factor significantly influenced the values of TPC, DPPH, ABTS, and FRAP. Based on the experimental design, the optimized extraction conditions were determined to be a solvent-to-liquid ratio of 100, a pulse number of 50, and a voltage of 6000 V. Under these conditions, the predicted values for TPC, DPPH, ABTS, and FRAP were 1326.67 mg gallic acid equivalents/100 g, 10213.75 µg trolox equivalents/g, 2161.81 mg ascorbic acid equivalents/100 g, and 15959.54 µmol Fe2+/100 g, respectively.

Significance

This study highlighted the potential of optimizing PEF extraction of bioactive compounds from red beetroot to reduce waste and obtain natural antioxidants. The optimized conditions offer a sustainable clean-label solution for the food industry.

Authors: Noemí Echegaray, Rubén Agregán, Mirian Pateiro, José Ángel Pérez-Álvarez, Juana Fernández-López, Roberto Bermúdez, Rubén Domínguez-Valencia, José Manuel Lorenzo