Cereal Chem 49:86 - 91.  |  VIEW ARTICLE
The Sugars of Flour and Their Involvement in the San Francisco Sour Dough French Bread Process.

R. M. Saunders, H. Ng, and L. Kline. Copyright 1972 by the American Association of Cereal Chemists, Inc. 

No sugars are added in the making of San Francisco sour dough French bread. Therefore, it is of interest to determine the sources and types of carbohydrates utilized by the two microorganisms recently reported to be involved in this process. The principal carbohydrate available, approximately 5.5% maltose based on dry weight of flour, is produced afer the flour-water mixture is formulated, presumably by amylase action on free starch. The flour itself contributes approximately 1.7% of additional carbohydrates other than maltose. The sour dough bacterium, a previously undescribed Lactobacillus, utilizes only about 56% of the maltose, conveniently leaving the remainder as a necessary ingredient in crust browning. The sour dough yeast, Saccharomyces exiguus, which does not utilize maltose, consumes virtually all of the flour carbohydrates including glucose, fructose, and two families of glucofructans: glucose(1)-fructose(n) (n 1 thru not less than 4). The contribution of the yeast to the acidity produced (lactic and acetic) is shown to be negligible.