Dough fermentation flavor

The composition of the volatile fraction of bread depends on the bread ingredients, the conditions of dough fermentation and the baking process. This fraction contributes significantly to the desirable flavors of the crust and the crumb. For this reason, the volatile fraction of different bread types has been studied by several authors. Within the more than 280 compounds that have been identified in the volatile fraction of wheat bread, only a relative small number are responsible for the different notes in the aroma profiles of the crust and the crumb. These compounds can be considered as character impact compounds. Approaches to find out the relevant aroma compounds in bread flavors using model systems and the odor unit concept are emphasized in this review. A new technique denominated "aroma extract dilution analysis" was developed based on the odor unit concept and GC-effluent sniffing. It allows the assessment of the relative importance of the aroma compounds of an extract. The application of this technique to extracts of the crust of both wheat and rye breads and to the crumb of wheat bread is discussed. 

It is generally accepted (1 ) that volatile compounds present in the flour are of minor importance to the aroma of bread. Prerequisites for formation of the desired crust flavor compounds are the dough fermentation and, especially, the baking steps (J2, 3). 

Lactic Acid B cteri. The lactic acid bacteria are ubiquitous in nature from plant surfaces to gastrointestinal tracts of many animals. These gram-positive facultative anaerobes convert carbohydrates (qv) to lactic acid and are used extensively in the food industry, for example, for the production of yogurt, cheese, sour dough bread, etc. The sour aromatic flavor imparted upon fermentation appears to be a desirable food trait. In addition, certain species produce a variety of antibiotics. 

Milk and Milk Replacers. White pan bread was long made with about 3—4% nonfat dry milk (NEDM) in the United States, for reasons of enhanced nutrition, increased dough absorption, improved cmst color, fermentation buffering, and better flavor. Eor some years, however, sharply increased milk prices have led to a decline in its use in breadmaking. Many bakers have turned to the use of milk replacers to control the costs of their products, and these ingredients are now commonly utilized. Milk replacers were designed to dupHcate some of the functions and nutrition of milk. These blends may contain soy flour or cereals, with whey, buttermilk soHds, sodium or calcium caseinate, or NEDM. Milk replacers or NEDM used in bread dough amount to about 1—2%, based on flour. 

Literature on the cause and control of the flavor of crackers is scant. Faridi and Johnson (10) studied the chemical changes related to flavor precursor components (organic and amino acids) during the twenty-five hour fermentation period. They measured the total soluble nitrogen, peptides, primary amines, and ammonia formed in cracker doughs as a result of the lengthy fermentation. All components increased... 

Laboratory production of crackers with the same flavor quality as commercial crackers has been difficult. Micka (11) found that when crackers are produced in a laboratory and no starter sponge is kept, and equipment is kept sterile, fermentation is generally retarded and the resulting dough has a high pH and the crackers have an undesirable flavor. Dynn (17) attempted to develop a procedure for the production of experimental crackers to test flour quality. He found that the crackers made from the same batch of flour varied widely in flavor quality and concluded that commercial crackers could not be produced in a laboratory. However, Pizzinatto and Hoseney (4,14) have recently developed a procedure for the production of satisfactory experimental saltine crackers under laboratory conditions. 

Function Binder dough conditioner emulsifier and emulsifier salt flavoring agent flavor enhancer nutrient fermentation aid surface-active agent texturizer. 

Fermentation has been known and commercially exploited for centuries. Products like spirit, liquor, wine, beer, and other alcoholic beverages vinegar cheese and yogurt miso, soy sauce, and fermented bean curd ham and sausage fish sauce cured vanilla beans, tea, and cocoa pickles and sauerkraut dough, bread, and other bakery products have special flavor notes that can also be used as seasonings. 

Bakers use either compressed yeast (compressed cakes of top yeast) or dried yeast (a mixture of yeast cells with starch). The former has high fermenting capacity and gives uniform results, but it will keep only a day or two while the latter retains its capacity to produce fermentation for a long period. Brewers yeast is not desirable for bread making because it is likely to give a bitter flavor and its activity is slow in a dough mixture. 

---