Impact of Thermal, Agitation and Microwave Assisted Extraction on Flavonoids from Red Beet (Beta vulgaris L)

Abstract

In recent years, there has been a growing interest in the biological activity of red beet and its potential utility as one of the health promoting and disease preventing functional food. The objective of the study was to investigate the influence of extraction techniques such as Thermal, Agitation assisted extraction (AAE) and Microwave assisted extraction (MAE) on flavonoid content of red beet using different solvent compositions viz., T1 Distilled water ii) T2-Distilled water + 0.5% citric acid, iii)T3- 20% Ethanol, iv) T4–20% Ethanol+ 0.5% citric acid, v)T5–50% Ethanol, vi)T6- 50% Ethanol +0.5% citric acid. The impact of solvent systems and extraction techniques were evaluated at different temperatures (40, 50 and 60°C), agitation speeds (150, 170 and 190 rpm) and microwave power levels (160, 320 and 480 W). It was found that highest flavonoid content was observed in AAE at 190 rpm as 11.62 mg quercetin equivalent (QE)/100g dry weight (DW)in T4 followed by 8.00 mg QE/100g DWat 480 W in T5 through MAE and 7.16 mg QE/100g DW in thermal extraction at 40°C in T5. The effect of solvent composition on extraction methods was found significant and MAE evolved as efficient process for the extraction of flavonoids from red beet.