Antioxidant Compounds and Activities in Selected Fresh and Blanched Vegetables from Northeastern Thailand

Abstract

This investigation aimed to identify the effect of blanching on 30 edible leaves of vegetables from northeastern Thailand on the total phenol content (TPC), total flavonoid content (TFC), 2, 2-diphenyl-1-picrylhydrazyl (DPPH), ferric reducing antioxidant potential (FRAP), and b- carotene bleaching activity. The results showed that blanching caused a significant (p<0.05) increase in TPC [fresh (0.39-0.85g/100g), blanched (0.60-1.84 g/100g)] and decrease in TPC [fresh (0.58-2.83 g/100g), blanched (0.27-2.58 g/100g)]. Interestingly, fresh and blanched Oxystelma esculentum reveal TPC and FRAP assay had high relationship (R2= 0.7423, R2= 0.6908). Blanching caused an increase or decrease in the antioxidant compounds and antioxidant activity depending on the specific vegetables. A highly positive correlation between TPC and FRAP in fresh and blanched vegetables was found. These results will be usefully when revising guidelines on the beneficial properties of local vegetables from the northeastern region of Thailand.