46C-13 |
Evaluation of three bean types as sources of natural antioxidants |
T. MADHUJITH, Biochemistry, Memorial Univ. of Newfoundland, Saint John's, NF A1B 3X9, Canada and F. Shahidi. Recently, there has been increasing interest in the protective biochemical function of natural antioxidants in dietary plant products in order to prevent oxidative damage caused by radical species. Although beans are cultivated throughout the world and consumed in both western and eastern dishes, little attention has been paid to their antioxidative potential. Therefore, objective of this study was to examine three varieties of beans for their antioxidant efficacy. Extracts of red, brown and black beans were prepared in 80% acetone. The solvent was removed and the extracts so obtained were subsequently used in the study. The antioxidative efficacies of seed extracts were evaluated using Trolox Equivalent Antioxidant Capacity (TEAC), 1,1-Diphenyl-2-Picryl-Hydrazyl (DPPH) and hydrogen peroxide radical scavenging assays. Chelation capacities of the extracts for Fe (II) were also determined using a colorimetric method. The total phenolic content, as mg catechin equivalents/g of extracts, were 93.56 ± 0.49, 91.37 ± 0.65 and 43.87 ± 0.57 for red, brown and black beans, respectively. TEAC values for red, brown and black beans were 8.84 ± 0.31, 7.46 ± 0.20 and 4.64 ± 0.61 at a final concentration of 3.4 mg/mL. All three bean extracts showed 100% scavenging of DPPH radical at both 50 and 100 ppm levels. The corresponding hydrogen peroxide capacities were 70.1, 69.1 and 67.0% (50 ppm), and 99.0, 95.1 and 96.0% (100ppm), respectively. The corresponding Fe (II) chelation capacities by 50 and 100 ppm were 60.0, 56.1 and 39.3% (50ppm), and 57.9, 61.9 and 43.1% (100ppm), respectively. Thus, red and brown beans show superior antioxidative capacity over black bean seeds. The results also suggest the potential of beans as nutraceuticals in preventing oxidative damage to cells.
Session 46C, Food Chemistry: Lipids, antioxidants and emulsifiers
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