The impact of steam-blanching and dehydration on phenolic, organic acid composition, and total carotenoids in celery roots

From the nutritional point of view, studying thermal and non-thermal processing effects is highly important for various nutrients which include numerous biologically active components in vegetables used daily. Therefore, the aim of current research was to study steam-blanching (at 1.5 and 3.0 min), convective drying, microwave-vacuum (MV) drying and then calculate the effect each had on individual organic acids, individual phenolic compounds, total phenolics, antiradical activity of phenolic compounds and colour within the celery roots. Fresh celery roots contain a trace amount of carotenoids which decreases significantly during drying. Total phenolic content in fresh celeries was determined in lower concentrations than flavonoids and during drying process their content increases. It was determined that celery roots dried with the convective method contained higher total phenolic content than those dried with the MV method, however, the highest flavonoid content was observed in the MV dried root samples which were preheated with steam. The determined individual phenolic compounds in higher amounts were: 3.4-dihydroxybenzoic, 4-hydroxybenzoic, chlorogenic, sinapic and t(3)-cinnamic acids. The determined major organic acids in higher amounts were oxalic, malonic, citric, ascorbic and succinic acids.