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Effect of Pepsin Hydrolysis on Amylase Activity and Lack of Amylase Inhibitory Activity of Sweet Potato Protein
Author(s) -
Patterson Katherine W.,
Truong Van den,
Clare Debra A.,
Allen Jonathan C.
Publication year - 2009
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.23.1_supplement.717.9
Subject(s) - amylase , chemistry , pepsin , food science , digestion (alchemy) , starch , hydrolysis , reducing sugar , sugar , potato starch , biochemistry , enzyme , chromatography
The objectives were to determine the effect of pepsin hydrolysis on amylase activity and test for amylase inhibitory activity of Beauregard sweet potato protein. Protein was extracted from sweet potato flesh, peel, and leaf. Samples with or without pepsin digestion at pH 2 were run on SDS PAGE. Proteins resistant to pepsin digestion were found in the flesh, peel, and leaf. Amylase activity and amylase inhibitory activity were determined using starch as substrate, sugar reducing ends as product, and dinitrosalicylic acid as the detection medium. Dinitrosalicylic acid reacts with sugar reducing ends to absorb at 540 nm. No amylase activity was found in the leaf extract. Digestion with pepsin eliminated amylase activity in the flesh and peel extracts. Amylase inhibitors were not apparent in any of the fractions before or after pepsin hydrolysis. Amylase inhibition by sweet potato protein does not appear to be the mechanism for the low glycemic response to Beauregard sweet potatoes. Gastric digestion is likely to eliminate native amylase activity in the sweet potato thereby requiring pancreatic amylase to digest carbohydrate in vivo. Support: N.C. Sweet Potato Commission. Grant Funding Source N.C. SWEET POTATO COMMISSION