Bread lactose

Yeast Fermenting in Dough. When yeast is in a bread dough the traces of sugars present can be fermented directly. As yeast contains the enzyme invertase, any sucrose present can be inverted into dextrose and fructose which can then be fermented. If any dextrose from a high DE glucose syrup is present then it can be directly fermented. If there is any lactose present it can not be fermented at all. Similarly, any polyols such as sorbitol can not be fermented. 

The main saccharide of milk is lactose. During heat treatment of milk, lactose is involved in Maillard reactions. Lactose is used for the production of baby formulas, low-caloric foods, bread, drugs, and microbiological media. 

The total daily intake of carbohydrate is -300 g of this, -250 g is starch, 30 g is sucrose, and 20 g is lactose. Cooked foods containing large amounts of starch include potatoes (average values) (12.4 g/100 g), rice (27.9 g/100 g), and pasta (24.6 g/100 g). A slice of bread weighing 30 g has 12.8 g of starch. Of the starches in a Western diet, bread contributes about one-half and potatoes about one-third. 

CaHjOj, Mr 126.11 crystals with a sweet-fruity caramel odor, mp. 164 °C (subl. at 93 °C) poorly soluble in water and alcohol. LD50 (rat p.o.) 1.4g/kg. M. is formed from lactose or maltose by the Maillard reaction , it was recognized as an odor substance in malt in 1894 and occurs, e.g., in "bread, "coffee, "cocoa, "meat and sake aroma, as well as in larch bark and pine needles. M. can be obtained from the latter by ex-... 

Around 70°C, the gelatinization of finely divided flours (starches) mixed with water can be observed. Retrogradation, for instance bread staling, can also be studied [97]. Crystallization of amorphous sugars (e.g., crystallization of amorphous lactose in milk powders [98]) can be detected in reconstituted foods. However, protein denaturation is no longer detected elearly when studying liquid whole milk products containing lipids, lactose, caleium, etc. 

Pan bread formulations usually contain small quantities of nonfat dried milk (1% to 3.5% based on flour weight). The milk slightly increases water absorption, and improves crust color (golden color) and flavor. It is noteworthy that yeast is not capable of breaking down lactose and therefore this disaccharide remains unaltered until the baking process, where it contributes to crumb color. Milk also improves nutritional value because its protein complements the amino acid pattern of wheat proteins and supplies important amounts of calcium, magnesium, and other essential nutrients (Doerry 1995, Kulp and Ponte 2000, Stauffer 1990). 

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