Effect of Heat Treatment on the Bioactive Components and Antioxidant Activity in Selected Dry Beans and Nuts

Abstract

Dry beans and nuts are vital in our daily diet and contains high dietary fiber, poly-unsaturated fatty acids and phytochemical compounds such as phenolic and flavonoids. The objective of this study was to compare the antioxidant activities in selected dry beans and nuts and the effect of roasting. Roasted and raw dried nuts and beans were grounded into powder, extracted in 70% methanol and evaporated. The methanol extracts were subjected to 1,1-Diphenyl-2-picrylhydrazyl (DPPH) scavenging assay, 2,2’-Azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) assay, total phenolic content (TPC) assay and total flavonoid content (TFC) assay. Results were analyzed using ANOVA (p value <0.05). The results of DPPH, ABTS, TPC and TFC assays were found in increasing pattern from cashew nut (CN), almond (AN) to walnut (WN) among nuts, and from chickpea (CB), green pea (GB) to mung bean (MB) among beans. Whereas in roasted condition, increased activities were found in CN, GB and CB while decreased activities were found in AN, WN and MB for DPPH assay. In ABTS assay, increased activities were found in CN, GB, CB and MB but decreased activities were found in AN and WN. For TPC assay, increased activities were found in all of beans and nuts except for WN. As for TFC assay, decreased activities were found among all nuts and beans except for CN and CB. The study indicates roasting process alters the antioxidant capacity (DPPH and ABTS), TPC and TFC in dry beans and nuts.

Keywords

• antioxidant
• nuts
• beans