IMPACT OF ELECTROTECHNOLOGIES AND ULTRASOUND TREATMENT IN THE FLAVONOIDS PROFILE OF A PAPAYA, MANGO AND STEVIA REBAUDIANA BEVERAGE

Abstract

A high content of flavonoids in beverages is desirable not only due to their beneficial health effects, but also due to their ability to protect fruit juices from oxidation. However, food processing has a profound effect on these phytochemicals, with the further loss of most of their beneficial properties. For this reason, five flavonoids (catechin, rutin, hesperidin, quercetin and apigenin) were analyzed by HPLC in accordance to Kelebek et al. (2015) in a fruit juice-stevia beverage before and after pulsed electric fields (PEF), high voltage electical discharges (HVED) and ultrasounds (USN) treatments at two equivalent energy inputs. Catechin and hesperidin were the mayor phenolic compounds. For this two flavonoids, along with quercetin, PEF and USN treatments resulted in a significant increase compared to untreated beverage. By contrast, rutin decreased after PEF, HVED and USN treatment. The highest decrease was obtained when the beverage was treated by HVED at 256 kJ/kg. Apigenin content was far much lower in the USN treated beverage, as this compound may be severely affected by the cavitation phenomena. Results obtained highlight that individual flavonoids undergo different changes immediately after HVED, PEF and USN treatments, whereas others remain unchanged or are even enhanced.