Bioactive Substance and Free Radical Scavenging Activities of Flour from Jerusalem Artichoke (Helianthus tuberosus L.) Tubers – a Comparative Study

Abstract

The Jerusalem artichoke (Helianthus tuberosus L.) known also as topinambour is plant with high importance for human and animal nutrition during the last decade. Its tubers were consumed fresh, stewed or they were added as flour in food products to improve their functional properties. In the current research a comparative study of bioactive substance and free radical scavenging activities of flour obtained from tubers of different varieties and wild populations of Jerusalem artichoke (Helianthus tuberosus L.) grown on territory of Bulgaria was done. The ultrasonic irradiation (42 kHz) was performed with 70 % ethanol and distilled water as solvents to accelerate extraction process. The total fructans, phenolic content and radical scavenging activities of the extracts were investigated. The 70 % ethanol extracts possessed the highest total phenolic content (6-17 mg GAE/g dry weight) and antioxidant activity defined by ABTS and CUPRAC methods. The water extracts characterized with higher fructan levels - 32 to 69 g/100 g dry weight. The flour obtained from tubers of Scorospelcu variety and wild population of Helianthus tuberosus L. were evaluated as a valuable source of total polyphenols and soluble dietary fibers, because of the rich fructan content. The results from our study also revealed the potential application of these flours as radical scavengers in human and animal nutrition for preparation of foods with improve health benefits