Cereal Chem 55:244 - 254. | VIEW
Protein Alpha-Amylase Inhibitors from Wheat Flour.
W. Pace, R. Parlamenti, A. Ur Rab, V. Silano, and L. Vittozzi. Copyright 1978 by the American Association of Cereal Chemists, Inc.
A number of pure gliadin fractions were tested for inhibitory activity on human salivary, yellow mealworm, and pig pancreatic alpha-amylases; all were inactive. Many extraction solvent systems commonly considered typical of wheat gliadins were found to be highly effective for extraction of albumin alpha- amylase inhibitors from wheat flour and gluten. Extraction of the bulk of amylase inhibitors from wheat flour was achieved with five consecutive treatments with 0.15M NaCl; use of 70% aqueous ethanol instead of the salt solution did not improve extraction of residual alpha-amylase inhibitors. These data all indicate that gliadin amylase inhibitors in wheat flour account for only a small fraction of the total inhibitor content. Alpha-Amylase inhibitors were tested at different stages of wheat kernel development. Inhibitory activity steadily increased during seed maturation and reached its maximum at the maturity stage. Throughout seed maturation, amylase inhibitory activity was inversely related to wheat alpha-amylase activity, but at no stage of kernel development did amylase inhibitors extracted from mature kernel inhibit wheat alpha-amylase. After germination, the content of amylase inhibitors of the kernel rapidly decreased and no inhibitory activity was detectable in newly formed tissues such as roots and coleoptiles. Preliminary comparison of gel filtration patterns of amylase inhibitors extracted from the kernel of 11 nullitetrasomic wheat strains showed a complex genetic control of alpha-amylase inhibitors.