INCREASING THE STABILITY OF POLYPHENOLS AND BETACYANINS IN BEETROOT CHIPS BY TREATMENT BEFORE DRYING

Abstract

An innovative trend in the production of snack products is the use of selected vegetables for the production of dried vegetable chips. Beetroot is a suitable vegetable for this type of product, as it is characterised by its high biological potential and its content of a wide range of phytonutrients with beneficial effects on human health. The aim of this work was to compare five varieties of beetroot in terms of the content of total polyphenols and betacyanins, to assess the effect of hot-air drying on these important components and to determine the appropriate method of treatment of beetroot slices before drying in terms of improving the stability of polyphenols and betacyanins during drying. In this work, 5 beetroot varieties (Betina, Renova, Cervena kulata, Pablo F1, Karkulka) were evaluated. The beetroot chips were dried at 70°C until a residual moisture content of 15±1% was reached. To treat the slices before drying a 0.1% solution of ascorbic acid, 0.01% solution of CaCl2, 0.01% solution of K2S2O5, 1% solution of NaCl was used followed by blanching in a water bath at 96°C for 2 minutes. The highest content of total polyphenols and beta-cyanins was statistically significant (p<0.05) in the variety Pablo F1. During hot air drying, both polyphenols and betacyanins decreased significantly. The average decrease in betacyanins and total polyphenols was 50.97% and 48.70% respectively. To mitigate these changes, treatment with 0.1% solution of ascorbic acid and blanching appeared to be the most effective of the treatments tested. After treatment with ascorbic acid solution, the dried products retained on average 27.6%  more betacyanins and 32.67% more total polyphenols than the control sample.