Dough processing route – first steps of the technological flow
Dough processing route – first steps of the technological flow
Flour, water, and yeast or other ingredients (as presented in chapter 2.3) are mixed, to obtain the dough; after the bulk dough fermentation as follows:
the operation of dividing into smaller pieces, the shaping of dough pieces into the desired final product form, and the final proof step. For traditional bread making, after mixing, the dough must be fermented for some time (could be 2/3/4 hours – depends on the technology type) before final processing.
During this period occurs a significant contribution towards gluten development. If an oxidizing agent is used, the gluten is developed in the mixer, saving a considerable amount of time.
The use of ascorbic acid in bread making is not as straightforward as other former permitted oxidants. Ascorbic acid can only function as an oxidizing agent in the dough after it has been oxidized to another form known as dehydro-ascorbic acid and to achieve this conversion oxygen is required.
With sufficient oxygen available the ascorbic acid first converts to the dehydrated form to oxidase the proteins and then having done so changes back to the original ascorbic acid form (fig.13).
The cycle continues as long as sufficient oxygen is available. Oxidation of bread dough promotes cross-linking of the protein molecules causing the dough to become stronger, and more elastic thus helping with the texture and shape of the final product.
Other dough ingredients use oxygen during mixing – most notably the yeast which will remove oxygen so fast that by the end of most dough mixing systems no oxygen remains in the dough for ascorbic acid conversion.
The net change of gases in the dough is from a mixture of oxygen and nitrogen to a mixture of carbon dioxide and nitrogen.
Therefore the contribution of oxidants to bread quality is significant, by improving dough development we will get larger product volume and improved crumb softness.
In some processing environments, we can also get finer cell structure which will give soft bread and whiter crumb color.
Ascorbic acid has a significant advantage over other oxidants in that since oxygen availability limits its action it is very difficult to over-treat by increasing the added level.
At best the ascorbic acid remains inactive once the oxygen has gone from the dough through it can now act as a reducing agent and break rather than create protein bonds.
The action of ascorbic acid is temperature-sensitive and as we lower dough temperatures it becomes less active and therefore gives less dough development.
In bakeries, there is always the temptation to reduce dough temperature to reduce yeast activity and make doughs easier to handle but in doing so there is a danger of reducing dough development and bread volume.
Emulsifiers such as glyceryl monostearate GMS, diacetyl esters of tartaric acid DATEM, sodium stearoyl lactylate SSL, and calcium stearoyl lactylate CSL, are sometimes seen as alternatives to the addition of hard fat in bread doughs (fig.14).
They certainly do improve gas bubble stability and like fat, they align themselves with the air bubbles in the dough.
However, they have quite different melting points and melting profiles and cannot be used directly
to replace solid fats with absolute certainty.
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