This refers to the colour of the bread beneath the crust. It is affected by the addition of ingredients such as malt flours or extracts as well as the choice of bread flour used. It can be affected by processing techniques and the results of these generally show up as a textural difference.
Crumb texture usually refers to the shape and size of the characteristic cells on the surface of a slice of bread. Open texture means the bubbles are very large and spaced apart. Conversely, a close texture means that the bubbles are very small and close together. The smaller and closer the bubbles are the whiter and shinier the crumb will appear.
The hue and depth of colour developed by effects of heat on the dough and the caramelisation of sugars. This can be affected by the addition of extra sugars in the form of malt flour.
This describes the movement of the dough piece in the pan before setting due to baking. It has been shown that very small additions of malt flour can aid the flow of some trayed products such as biscuits.
The small cell nuclei developed during mixing are expanded by CO2 during the process of fermentation. For fermentation to occur the yeast needs food. This is provided in the flour in the form of fermentable sugars, which are converted from damaged starch by the enzyme alpha amylase. Alpha Amylase is present to some extent in most wheat flours but can be topped up by the addition of diastatic malt flour.
Oven spring is the dramatic increase in volume of bread and rolls during the first 10-12 minutes of baking. As the temperature of the dough rises, it becomes more fluid. The amylase enzymes are more active and the rapid conversion of starch to dextrins reduces the water holding capacity of the flour. The more fluid dough is less able to resist the pressure of expanding gases. Also production of CO2 is accelerated and the oven heat causes the gas to expand within the cells.
Diastatic malted ingredients improve the dough gas retention, especially in the early stages of baking which results in improved oven spring and a higher finished product volume. This is useful in products like Italian breads, French sticks, Vienna bread and rolls, and other long fermentation products.
As the yeast cell ferments sugar, CO2 is produced as a waste product. The fermentation reaction is as follows.
C6H12O6—————-> CO2 + 2C2H5OH
It is the CO2 gas that acts on the dough, as gas bubbles of CO2 collect in the flour mixture. As more and more gas is generated, the volume of the dough increases, and the dough is converted to foam. As the bubbles of gas expand, the gluten is stretched into a film surrounding the bubble.
Because of the way alpha amylase works on the damaged starch in the bread flour, large quantities of dextrins are produced. Dextrins are sticky substances and over production will result in a weak and sticky crumb if fermentation is checked prematurely.