Effect of drying methods on physicochemical parameters of different red beetroots (Beta vulgaris L.) species

Abstract

The aim of this work was to study the influence of atmospheric, vacuum and microwave vacuum drying methods on the quality of dried beetroots. Three different red beetroot species (‘Alto F1', ‘Cylindra’, ‘Detroit’) were chosen in this study. The microwave vacuum method reduced the total time of drying and decreased the shrinkage compared to the other drying methods. The quality of the dehydrated material was described by its color change, antioxidant capacity, total polyphenol, betacyanin, betaxanthin and each phenolic acids content. The attempts were made to suggest the microwave vacuum method for red beetroot samples as a gentle drying technology to reach a special texture that is favoured by costumers. During the experiments relevant differences could be observed between the investigated beetroot species on the effect of different drying methods. According to the examined parameters the ‘Cylindra’ species proved the most appropriate beetroot variety for microwave vacuum drying. Based on the results, the combined methods with hot-air at 60 °C followed by microwave vacuum finish drying was the most suitable assay to preserve the investigated parameters in the highest amount.