Why gluten breaks down Author Elena Zheleznyak
🔗If you knead the dough for a very long time or very intensively, you can knead it, then its gluten will collapse and it will become unsuitable for further work. This can happen for several more reasons: it fermented for too long, overexcited, became very hot and suddenly began to tear, stick and smear. I'll start from afar, but ideally I want to come to an understanding of what the bread dough consists of and how it breaks down.
We have already said something
About the features of kneading bread dough, but I would like to return to this topic and dive deeper inside the test and processes, see what affects what and how. I recently opened a book by L. Ya. Auerman on the section devoted to kneading, ran, and caught on to the moment, which I passed more than once, not paying attention. It turns out that during kneading, there are three jumps inside the dough, when the dough dramatically improves its properties. The first one occurs at the initial stage of kneading in 1-2 minutes, when flour and water are mixed and become a homogeneous mass. The second - at about the 24th minute of kneading, when proteins noticeably swell in the dough and it becomes elastic. I understand that just during the second jump, we usually decide that the kneading should be stopped, because the dough has reached the necessary properties. But the third jump occurs as early as 48 minutes, it is not as obvious as the previous two and is preceded by a prolonged deterioration in the properties of the test. At the time of this jump, the gluten is already beginning to break down in the dough.
Fuuh, tired? I hope not, because this is a very interesting topic. Even dawn on purpose woke up to sit quietly while everyone was asleep and finish writing an article so that children would not jump on their heads)) In general, if you are interested in the nature of kneading and mixing the dough, what and how it happens, let's consider in more detail.
Opara.
I will briefly dwell on how to knead the dough. Recently I met the opinion that the dough should be kneaded, while trying to develop gluten. Almost in a harvester it needs a mess to have an "effect".
I specifically looked for information on this topic, as always, Auerman helped. According to the opinion stated in the book "Technology of bakery production", the dough does not need to be kneaded strongly, it is enough to knead it until smooth so that there are no unmixed lumps of flour. This consistency is already considered sufficient to leave the dough to ripen. In addition, during fermentation, the necessary processes will take place in it, the protein will swell and gluten will develop by itself.
Dough and gas phaseDuring kneading, the first thing that should happen to the flour and water is mixing until smooth. Only after that all further processes necessary for flour and water to become dough can occur in this mixture.
Usually the dough is considered as a mixture of liquid and dry matter, the constituent components of which influence each other in different ways, change, and thereby form the properties of the dough. It seems that everything is obvious: the dough contains water and flour, a solid phase and a liquid phase, but few people thought (I do not mean technologists, but you and I are amateurs) that there is also a gaseous phase, which can be on average 10-15% of the entire dough volume. Moreover, we are not talking about the gas that loosens the dough due to the vital activity of the yeast, but about the gas that appears in it during the kneading process.Technologists experimented with this and deliberately increased the kneading time, and so, with prolonged work, the dough volume increased up to 20% due to the air trapped in the dough during kneading. In addition, air, in particular, oxygen, that got into the dough, had a positive effect on its properties and had a firming effect on gluten.
Solid phase. All components of the solid phase are insoluble components of the dough, they bind water - absorb it, while they themselves swell and increase in volume. Moreover, flour is not a completely "solid" phase, because it contains many substances that dissolve in water. In addition to the main component that makes up the "hard phase" of the dough - flour protein, which can absorb twice as much water as its own mass, these are also particles of grain shells, bran and starch grains. At the same time, starch is generally unique. Before being ground in a mill, it consists of whole starch grains and is able to bind up to 44% moisture. But after grinding, its structure is disturbed and its damaged grains become capable of absorbing up to 200% of water.
Slimes (water-soluble pentosans) also bind water, which can absorb up to 1500% on dry matter, but they belong just to the liquid phase.
Liquid phase - this is water and substances that dissolved in it during the kneading of the dough. They were not absorbed by starch, proteins or grain particles, but remained a mixture of mineral and organic substances. The liquid phase also includes sugar, salt and mucus, and the liquid phase in the dough looks like a viscous liquid surrounded by particles of a solid phase. By the way, oils often enter the liquid phase, but not always. If this is a liquid vegetable oil, then it becomes an emulsion in the liquid phase, and if it is cold butter, then it goes to the solid phase and becomes films on the surface of the particles of the protein framework of the dough.
Based on this, we can conclude that the dough consists of three phases: liquid, solid and gaseous. However, not everything is so unambiguous, because these phases are not constant, they change and affect each other, and from this the properties of the bread dough change. By the way, here we come close to the ruins of destroyed gluten)
What is gluten breakdown.Under the influence of enzymes, acids, temperature and mechanical stress, the solid phase (especially the proteins of flour) can turn into a liquid, making the dough more liquid, sticky and smearing. If this has begun, you will immediately understand that something is wrong: until recently, the elastic dough suddenly becomes sticky and smeared, and leaves hard-to-remove marks on the hands and dishes, similar to window putty. This means that the flour gluten has suffered from enzymes, acids and some external factors and is gradually destroyed.
What is gluten breakdown? What is gluten anyway? It is a flour protein that does not dissolve in water, it remains "solid" and for the most part it is from it that the "frame" of the dough is built. When it is said that the gluten has broken down, what is really meant is that the protein in the flour began to dissolve and become a liquid phase.
When the dough framework begins to collapse, the ratio of the phases that make up this dough begins to change: the volume of the liquid phase increases, that is, the liquid becomes larger, and the solid phase that can hold this liquid becomes smaller.
Conditions and reasons.But the destruction of gluten during kneading does not just happen, for this you also need to "try". Here are the most common reasons, as a result of all this spread of thought along the tree
- Excessive mechanical stress. As you remember, at the 24th minute of kneading, there is a sharp improvement in the condition of the dough, and after that its properties deteriorate until the next slight improvement and further destruction of the protein framework. But this experience cannot be taken as an absolute truth, because, for example, kneading the dough with your hands for longer, and at a slow kneading speed, kneading the dough is more gentle than at a high speed.I have already got used to my Ankarsrum Original and I knead almost any soft dough at low speed for about 15-20 minutes, after which I turn on a more intensive kneading for a couple of minutes so that the dough “grabs”. At first I used a roller for these purposes, but now I often use a hook, it turns out much more efficiently.
- Temperature. During kneading, the dough heats up simply from the fact that water is mixed with flour, plus it heats up from mechanical stress. In the initial stages of kneading, this only contributes to the formation of the dough, but further heating above 25-30 degrees helps to liquefy the dough.
- Too long staying / long autolysis without salt... To a certain extent, salt inhibits the action of flour enzymes, strengthens the protein and contributes to its greater moisture capacity. It is believed that prolonged autolysis without salt can damage the dough and gluten, for example, Professor Raymond Kalvel considered autolysis and kneading without salt unacceptable, because this negatively affected not only the properties of the dough, but also the taste and aroma of the finished bread.
- Acids. The presence of acids in the dough acts in different ways, its scanty concentration in the dough (for example, added with a ferment) strengthens the gluten and promotes its rapid swelling. But an excess of acid destroys gluten, as well as prolonged exposure to even a small amount of acids on the dough. Therefore, for example, the sour thick dough from the refrigerator, which I wrote about in the last article, "fizzles out" much faster than soft bigi with yeast and its shelf life does not exceed four to five days.
- Flour enzymes... Flour itself may already contain the reasons for the destruction of gluten. For example, it can be ground from sprouted grain, which has a much higher enzymatic activity than ordinary flour. This flour is practically malt, which is added to the dough in small quantities to add nutrients and sugars to the dough.
By the way, whole grain flour, containing all the elements of whole grain, also has a high enzymatic activity and its gluten breaks down much faster than the gluten of white wheat flour and gains acidity faster, so I prefer to add whole grain flour directly to the dough and not use it in doughs.
The information is a bit too much, I hope it is clearly stated, if anything - ask. Maybe this will help the godfather to understand the secrets of bread dough and how it turns out.
Happy experiments and delicious bread!
