The effect of different processing methods on phenolic acid content and antioxidant activity of red beet

Red beet is a rich source of phenolic acids and has high antioxidant capacity. Effect of and different processing methods (microwave, vacuum, boiling, roasting and germination) on phenolic acid (HPLC) content and antioxidant activity of red beet were studied. The measured antioxidant activity included free radical scavenging activities against DPPH and ABTS. Among the phenolic acids from red beet extracts, 4-hydroxy benzoic acid was the major constituent followed by cinnamic acid, vanillic, chlorogenic, trans ferulic acid and caffeic acid. The concentrations of the phenolic acid differ depending on treatments. The present study exhibited that there was increase in phenolic acid concentrations with high vacuum treatments, roasting for 5 min and also with germination. Different phenolic acids seem to be more stable with vacuum treatment. The antioxidant activity has gradually increased to 1.5 to 3 fold during different treatments when compared to control. With high vacuum treatment there was up to 13% increase with DPPH assay and 11% increase with ABTS assay. (c) 2012 Elsevier Ltd. All rights reserved.