Effects of Dehulling on Phytic Acid, Polyphenols, and Enzyme Inhibitors of Dry Beans ( Phaseolus vulgaris L.)

ABSTRACT Effects of dehulling on phytic acid; trypsin, chymotrypsin, and α‐amylase inhibitory activities; and tannins of ten cultivars of dry beans ( Phaseolus vulgaris L.) were investigated. Phytic acid content of whole beans ranged from 1.16‐2.93%. Dehulling significantly increased the phytic acid content of beans (range 1.63‐3.67%). Dehulling also increased trypsin, chymotrypsin, and α‐amylase inhibitory activities of the beans. Tannin contents of whole and dehulled beans ranged from 33.7‐282.8 and 10.0‐28.7 me. catechin equivalent/100g beans, respectively. Removal of seed coats lowered the tannin content of beans by 68–95%. Tannins were not detected in white seeded cultivars of Sanilac, Great Northern, and Small White. Dehulling significantly improved the in vitro digestibility of bean proteins.