Impact of the Anodic and Cathodic Electro-Activation Treatment on the Physico-Chemical and Antioxidant Capacity of Red Beetroot Juice

Abstract

The aim of the present work was to study the feasibility of using electro-activation as a nonthermal treatment to produce stable beetroot juice. Specifically, red beetroot juice was electro-activated under two different reactor configurations by using three electric current intensities (100, 200, and 300 mA) during 120 min. Different parameters of the juice were measured such as the pH, redox potential, juice titratable acidity, Brix degree and total dry matter, color, betalain and polyphenolic contents, and antioxidant capacity of the electro-activated juice. By using the reactor Configuration A in which the targeted juice was electro-activated in the anodic compartment of the used reactor, acidic juice with pH 4 and 5 as well as a redox potential close to +300 mV was obtained. The Brix degree, color, dry matter, and phenolic content were not significantly influenced by this electro-activation. However, the treatment permitted increasing the antioxidant capacity of the juice as measured by the DPPH and ABTS assays. By using the reactor Configuration B in which the targeted beet juice was electro-activated in the cathodic compartment of the used compartment, a juice with an alkaline pH of approximately pH 9 and a reducing redox potential of -697 mV was obtained. With this reactor configuration, the Brix degree and total dry matter were not affected, but the color and total polyphenolic content changed. The betalains and polyphenolic compounds were degraded under the alkaline conditions of this electro-activation treatment, which had a negative consequence on the juice quality by decreasing its antioxidant capacity. In conclusion, this study demonstrated that anodic electro-activation of a beet juice can be technologically feasible since this treatment permitted producing stable juice as well as maintaining the main physico-chemical properties of the juice, enhancing its antioxidant capacity, and keeping the juice color at high level.