Influence of steam treatment and drying on carrots composition and concentration of phenolics, organic acids and carotenoids

Abstract

Carrot (Daucus carota L.) is a globally used vegetable from the Apiacea family. It contains macro and micro elements, as well as various phytochemicals. The aim of the study was to determine concentration of carotenoids and organic acids, phenolic composition and antiradical scavenging activity, and colour changes during steam-blanching (for 1.5 and 3.0 min) and in dried carrots in convective and microwave-vacuum driers. Gravimetric, spectrophotometric, and high performance liquid chromatography (HPLC) methods were used for analysis. Carotenoids in fresh carrots were detected in high amounts, which decreased during thermal treatment and drying. The main organic acids in fresh carrots detected in highest amounts were oxalic, tartaric, quinic, malonic, and citric acids. Ascorbic acid concentration decreased minimally with steam processing, but significantly during drying. Fresh carrots contain minimal amounts of total phenolics, which increased during the thermal and drying processes used, while flavonoid, flavonol, flavan-3-ol and phenolic acid concentration decreased. The compound found in highest amounts by HPLC methods were 3.4-dihydroxybenzoic and 3.5-dihydroxybenzoic acids, catechin, 4-hydroxybenzoic acid, epicatechin and sinapic acid.