Betalains, total polyphenols, and antioxidant contents in red beetroot peel (Cylindra type)

Abstract

Since significant percentage of fruits and vegetables go to waste during processing, investigation of how to improve the valuable products of extraction from the wastes is an undeniably effective way to save the planet. Beetroot (root, peel, and stalk) is a chief source of natural betalain color compounds and phenolic compounds with copious radical scavenging activity. The major emphasis of this work is to optimize process variables which are extraction time (10–60 min), operating temperature (20–50 °C), and aqueous ethanol solvent with the concentration of (25–75%) for effective extraction of valuable compounds such as betalains, total polyphenols, and antioxidant activity from beetroot peel. Spectrophotometric analysis was applied for quantification of those compounds. Amongst which, lowest solvent concentration (25% v/v) together with the highest temperature (50 °C) and extraction time (50 min) brought yielded higher results. The process optimization was carried out using Design Expert (11.0.3) statistical software. Overall, it can be noted that extraction process can be improved by controlling operating time and temperature, avoiding unnecessary overuse of costly solvent.