Purpose: The objective of this study was to evaluate the α-amylase inhibitor activity (AIA), chymotrypsin inhibitor activity (CIA), hemagglutinating activity (HA), and total phenols (TP) in select dry bean seeds.
Methods: Twenty-two dry bean seeds were purchased from local grocery stores and ground to pass through 40-mesh sieve. Dry bean flours were extracted with water (1:10 w/v, 4°C, 12 h), 0.05 M HCl (1:15 w/v, 4°C, 12 h), 0.01 M phosphate buffered saline (1:5 w/v, 25°C, 1 h), and 70% ethanol (1:10 w/v, 25°C, 1 h) for AIA, CIA, HA, and TP, respectively. N-benzoyl-L-tyrosine ethyl ester (BTEE) and 1% potato starch were used as substrates for CIA and AIA, respectively. HA was determined using 2% (v/v) human blood erythrocytes (group O, A, B, and AB). TP were analyzed using Folin-Ciocalteu reagent.
Results: AIA (0.0-1.3 inhibitory unit/mg), CIA (19.9-484.9 inhibitory unit/g), HA (0-10254 hemagglutinating unit), and TP (0.4-2.9 mg gallic acid equivalent/g) exhibited significant (P ≤ 0.05) differences between the samples. AIA was detected only in Phaseolus vulgaris beans. Val bean registered the highest CIA followed by the Phaseolus spp. Phaseolus vulgaris, tepary, and val beans contained abundant hemagglutinating activity while this activity was not detected in chickpea, cowpea, garbanzo, and moth beans. No blood group specificity was observed for hemagglutinating activity in the tested beans except for baby lima bean (blood group A specific). Soybean had the highest amount of TP.
Significance: A wide range of activity was detected for the tested analytes in the selected dry bean seeds. This information may be useful for optimizing processing conditions to remove the selected analyte.