Cereal Chem. 71:58-63   |  VIEW ARTICLE


Effect of Baking on the Microstructure of Rye Cell Walls and Protein.

T. Parkkonen, H. Harkonen, and K. Autio. Copyright 1994 by the American Association of Cereal Chemists, Inc. 

Rye doughs and breads were baked from whole meals milled from two rye varieties, a Canadian Muskate and a Swedish Danko. A study was made of the effect of beta-glucanase and xylanase incubation on the kernel cross-sections. beta-Glucanase studies indicated that beta-glucans are evenly distributed in the endosperm cell walls of the rye kernel. Xylanase treatment degraded only peripheral endosperm cell walls and had greater effect on the Muskate rye kernels. This finding suggests that wall structure varies in the different parts of the rye kernel; hence variety or growing conditions, or both, play an important role in the structural features of the plant. Examination of the microstructure of the doughs and breads indicated that proteins are of major importance in the structure of the rye dough just after mixing. The Muskate meal was milled finer, and protein was released from the cells to the dough matrix. The Muskate dough components were tightly stuck together. The Danko dough was less cohesive and more rigid than the Muskate dough just after mixing, evidently because of a higher content of big, unbroken particles in the Danko dough. As baking proceeds, endosperm walls are fragmented and, along with starch, their role in the formation of the continuous matrix increases. The Danko bread contained long, unbroken aleurone layers that, combined with a weak protein matrix, possibly decreased extensibility of the dough and distorted the gas cell structure. The Danko bread crumb was less elastic and more porous than the Muskate bread crumb.