Bread-making is a very old art. Over the centuries, a great number of techniques has been developed to impart a specific flavor and taste to the typical product of fermentation of flour mixed with water and certain yeast and bacteria. It has long been known, for example, to utilize the nutritional value and flavor qualities of milk in bread making processes.
Improving and enhancing the flavor of bakery products is still a great concern for cereal scientists. Bread processes have significantly shortened and fermentation times as well as mixing times are kept at minimum. Therefore, microorganisms involved in panary fermentation do not have time to produce much flavoring materials in dough. In recent years, some bread-making processes have undergone numerous changes to satisfy the consumer who is now more open to diversified products such as bagels, muffins and sourdough bread. The latter is a bakery product with a very unique flavor. The product is particularly popular in the San Francisco area. A traditional process of making sourdough bread consists of providing wheat flour (rye may be used) and varying proportions of water, and allowing the mixture to ferment at room temperature until optimum flavor and acidity develops. The "starter" mixture is reworked regularly by adding flour and water to ensure that it contains sufficient amounts of fermentable compounds. Fermentation can therefore take several days and the resulting leavening agent is incorporated into the dough in quantities varying from 15 to 80% on the basis of flour. This multistage process is still widely used today despite its deficiencies, i.e., duration, inconsistency of product quality and difficult process control.
A number of approaches have been proposed to modify the sourdough process, or, in general, to develop bakery products with different taste, or flavorants for the bread making process. Adding flavoring compounds (commercial bases) to the dough is one strategy employed to reduce fermentation time (Ziemke and Glabe, U.S. Pat. No. 4,034,125). The latter proposal serves to reduce the production time and assure better control over the finished product, the trade-off being the taste of bread produced in this fashion. Kline (U.S. Pat. No. 4,140,800) proposes to use a freeze-dried culture of lactobacilli (L. sanfrancisco) to better control sourdough production and to reduce sourdough preparation time to approximately 18 to 10 hours. Others have tried to imitate the sourdough process by adding acid whey power and vinegar to the dough (Shenkenberg, et al., 1972, Food Prod. Dev. 6(1), 29-30, 32). Another means of enhancing the flavor of bread is to use 4-6% (flour basis) non-fat milk solids (NFMS) during bread-making. To cut costs, NFMS may be replaced, at least in part, with whey powder which is less expensive and also improves to some extent the color, aroma and taste of the finished product.
Jaeggi, et al., U.S. Pat. No. 4,001,437, propose to manufacture aroma substances, or flavorants, by heating a liquid product, obtained from carbohydrate-containing milk products by enzymatic proteolysis and/or by lactic acid fermentation. The final product has a bread-crust flavor reminiscent of roasted cheese.
Hill, U.S. Pat. No. 3,846,561, incorporates yogurt in the dough from which baked products are prepared.
Jaeggi and Hill processes involve bacteria of the genera Lactobacillus or Streptococcus. For yoghurt (Hill process), Lactobacillus delbrueckii subsp. bulgaricus and Streptococcus thermophilus are the specific bacteria to be used.