Dough preparation Mixing, fermentation, dividing, final proof – main processes involved
Dough preparation Mixing, fermentation, dividing, final proof – main processes involved
dough preparation could be made mainly in three methods: – Direct method – all the ingredients are mixed in a single phase – Semi-direct method – the dough is obtained also in a single phase, but a certain quantity of the previously fermented dough is added- Indirect method – there are two phases: In the first, a pre-dough is prepared (could be biga or poolish) what is added in the second phase to the dough already fermented, together with the others ingredients.
Bread making starts with the formation of viscous dough developed in a mixer – during mixing, gluten structure is developed and starch particles are wetted.
Gluten formation is the main physical-mechanical process that occurs during dough formation. As mixing progresses, the air is incorporated and distributed in small fine cells.
Yeast is producing CO2 during mixing and subsequent steps of bread making that is diffused in these fine cells, which are inflated by the rising internal pressure.
Biochemical processes occur also in this phase of dough formation: lipids, carbohydrates, and protein transformations facilitated by the enzymes (from flour and yeast) presence.
Various bonds formed between the gluten proteins and other components, such as soluble proteins, mineral salts, starch, and lipids, leading to the formation of a homogeneous and uniform mass – the dough.
The microbiological processes, that involve the dough microbiota, are represented by the yeast cells and lactic bacteria multiplication, followed by the alcoholic and lactic fermentation.
The fermentation goal is to obtain such a dough that could optimum performance during the developing, fermentation, and baking phases. During fermentation the processes initiated in the mixing period are going on: the proteins molecules in gluten swell and absorb the CO2 formed by the yeast, therefore realizing a network between them and conferring a spongeous structure. Under the reaction of proteolytic enzymes more malleable dough is obtained.
During the fermentation, the dough had undergone a temperature increment of 2 – 3 °C, due to the decomposition of the sugar by the yeast.
At the same time, the dough weight at the end of the fermentation is lower by 2-3%.
The losses are caused by the fermentation of sugars (solid) in volatile substances (CO2 and ethyl alcohol) that partially evaporate, and by the water vaporization.
After mixing and bulk fermentation, the dough passes through other operations such as dividing, rounding, resting, conveying, sheeting, curling, elongating, cutting, folding, and panning – depending on the shape of the final product – that could damage the gluten formed.
If the dough is squeezed, sheared, or screwed the structure breaks down – the result in the loaf is streaks of coarse, firm texture with poor color. If dough structure is weak from the use of low protein flour, high starch damage, and high water addition, it needs to be handled very gently to get the best performance.
If the structure is strong from the use of a combination of good quality high protein flour, moderate starch damage, and water addition, properly formulated and fully developed, there is high built-in resistance to changing shape – particularly from a ball to sheeting and more relaxation time is required between these molding operations.
Levels of added fat used in bread dough are little but highly functional and the effects of fat are also combined with the functionality of native wheat lipids and added surfactants.
Liquid oils are known to hurt the volume of bread, especially under the time dough method. They are destabilizing the air cells so loaf volume is reduced and crumb structure is damaged.
The solid fat has proved to assist gas retention – these solid platelets tend to orient themselves around the air cells and stabilize the foam, providing a solid wall around the air cell.
During the shaping operations the dough is formed according to the final product specifications; then a fermentation phase – the final proving, is developed to assure an optimum volume of the product.
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