Cereal Chem 58:355 - 359.  |  VIEW ARTICLE
Alpha-Amylase in Field-Sprouted Wheats: Its Distribution and Effect on Japanese-Type Sponge Cake and Related Physical and Chemical Tests.

K. F. Finney, O. Natsuaki, L. C. Bolte, P. R. Mathewson, and Y. Pomeranz. Copyright 1981 by the American Association of Cereal Chemists, Inc. 

To clarify the effect of field sprouting on quality, we determined alpha-amylase activity (0-4.13 dextrinizing units [DU] per gram) in soft white winter wheat composites with typical levels of field sprouting (0-36.2%) and in their mill fractions, and we studied its effects on the Japanese type of sponge cake and in related tests. Average yields of the corresponding mill fractions of seven wheat composites were patent flour, 45%; midpatent flour, 10%; clear flour, 15%; bran, 25.8%; shorts, 3.2%; and red dog, 1.0%. Ash and protein contents of the fractions were typical. Alpha-amylase activity was relatively low for 45% patent, midpatent, and clear flours and relatively high for bran, shorts, and red dog. When alpha-amylase activity in DU per gram of each mill fraction was calculated as DU per gram of wheat, based on yield, activity increased linearly in each mill fraction with increasing wheat alpha-amylase. When expressed as percent of wheat DU, bran accounted for 42% of the alpha-amylase activity, patent flour for 32%, shorts for 9%, clear flour for 8%, midpatent flour for 7%, and red dog for 2%. Sponge cake volume increased from 1,280 Cereal Chem for the control to 1,315 Cereal Chem for the flour milled from wheat containing 0.35 DU/g. Thereafter, volume decreased rapidly to 908 Cereal Chem as DU per gram of wheat increased to 4.13. At least 0.2 DU/g of wheat (about 2.5% sprouted wheat) shoud be a doubly safe level that would have no adverse effect on sponge cake quality. Sponge cake volume, percent of sprouted wheat, amylograph viscosity, falling number, and gas production were all functions of the alpha-amylase activity of wheat or flour. Different levels of field sprouting should not be simulated by supplementing unsprouted wheat with a highly sprouted one, especially not with a highly malted barley.