Varieties of baking powder, features of the action of each of them Four types of gases are used to loosen the dough: carbon dioxide, water and / or ethanol vapor, ammonia and air. Of course, air is a mixture of different gases and is present (used) in all baked goods. Water is also present in all baked goods, but its leavening capacity is very limited in most cases because it has a relatively high boiling point.
Water vapor are only effective as a baking powder if the product is heated quickly (such as in salt crackers). Carbon dioxide can be produced from a chemical reaction of bicarbonate or carbonate with acids, and loosening of soft wheat flour products is most often done through this chemical reaction.
Sources of carbon dioxide are chemical leavening agents. Chemical leavening agents can be divided into three groups: alkaline, alkaline-saline, and alkaline-acid.
Often only
alkaline leavening agents.When heated
ammonium bicarbonate decomposes, forming three gases:
NH4HCO3 → NH3 + CO2 + H2O, (1)
Ammonium bicarbonate (ammonium carbonate salts) can only be used in products where the moisture content is reduced to approx. 5% during baking. If more moisture remains in the product, then it will also contain ammonia, even a small amount of which will make the product inedible, and therefore ammonium bicarbonate is used to a limited extent (but it is quite widely used in recipes for biscuits and in some products such as snack crackers). The advantage of this substance is that no salts remain after the reaction (the latter affect the taste and / or rheological properties of the dough).
Ammonium carbonate (NH4) 2CO3 (otherwise - ammonium carbonate acid, food grade ammonium carbonate) is a white crystalline substance. It is characterized by a pungent smell of ammonia, which arises from the instability of ammonium carbonate in air and slow decomposition at above-zero temperatures. When baking products with an increase in temperature, this process intensifies, resulting in the formation of gaseous products - carbon dioxide and ammonia. The decomposition reaction proceeds according to the equation:
(NH4) 2CO3 = 2NH3 + CO2 + H2O, (2)
The peculiarity of this substance as a chemical disintegrant is that when heated it decomposes entirely with the formation of about 82% of gaseous substances (CO2 and NH3) and about 18% of water vapor, that is, this substance is a more effective disintegrant than sodium bicarbonate. Ammonium carbonate contains 28 ... 35% of ammonia. One part of it must completely dissolve in five parts of water.
Potassium bicarbonate is also a potential source of carbon dioxide for loosening, but it is hygroscopic and also imparts
bitter taste.
The loosening effect of sodium bicarbonate (baking soda, sodium bicarbonate, sodium bicarbonate) is manifested when heated, when it decomposes with the release of carbon dioxide according to the equation:
2NaHCO3 = Na2CO3 + CO2 + H2O, (3)
Sodium bicarbonate as a baking powder, it has a number of disadvantages: the reaction of its decomposition does not go to the end, therefore, only 50% of the contained CO2 is released, which goes to loosening the flour semi-finished product. The rest of the CO2 forms Na2CO3 - an alkaline compound that colors the product in
yellowish color, gives flour products a specific
(soapy) alkaline taste and promotes
destruction of B vitamins in them.
Wide application
baking soda due to its many advantages, namely: 1) it is relatively cheap; 2) non-toxic; 3) easy to use; 4) practically does not add any flavor to the final product; 5) industrial soda contains almost no impurities.
As a source of carbon dioxide, one could use
sodium carbonate, but this substance is not used due to its high alkalinity, in connection with which there is a risk of a significant increase in the pH level, and this can make the finished product unsuitable for food.
To alkaline-salt baking powder includes a mixture of sodium bicarbonate and neutral salts. A mixture of sodium bicarbonate and ammonium chloride is used. The reaction proceeds according to the equation:
NaHCO3 + NH4Cl → NaCl + CO2 + NH3 + H2O, (4)
As a result of the reaction, along with gaseous products, table salt is formed, which is often a component of the recipe.
To understand how carbon dioxide works as a loosening agent, you should familiarize yourself with its chemical properties. Carbon dioxide reacts with water to form carbon dioxide:
CO2 + H2O → H2CO3, (5)
Carbon dioxide can exist both in the form of free CO2 and in the form of two types of ions: HCO3- or CO32-. The relative amount of each is determined by the pH of the solution and its temperature.
Above pH 8.0 loosening gas
CO2 in system
is absent... Many soft wheat flour products have a pH value of about 7.0, at which only a fraction of the CO2 is gaseous.
To increase the output of carbon dioxide and regulate the intensity of its formation,
acids are added to the dough... When kneading solid or liquid dough, sodium bicarbonate dissolves quickly in water. At the same time, the pH of the dough rises to such values at which carbon dioxide is not emitted, and
the dough must contain acid in order to generate enough gas... Different ingredients can be used as sources of acid. Illustrative examples are
sour fruit or buttermilk... For rich bakery products, the use of sodium bicarbonate gives a good result; the recipe includes whey, sour cream and other fermented milk products.
If the recipe does not have a natural source of acid, then it must be added. Heating NaHCO3 (soda) in an aqueous system leads to a redistribution: about half of the CO2 is released as a gas, and the rest is involved in the formation of sodium carbonate.
To alkaline acid baking powder includes a mixture of sodium bicarbonate and crystalline food acids or their acidic salts (otherwise - acidic baking powder).
In practice, baking powders are used - a mixture of sodium bicarbonate and acid.Sodium bicarbonate emits carbon dioxide as a result of thermal decomposition
at 90 ° C, but it's too late, because at this temperature
the structure of the product has already stabilized and is no longer able to expand... There are several suitable food acids that react with sodium bicarbonate at different rates and form different salts that remain in the finished product.
This baking powder consists of a mixture of baking soda, one or more acidic salts, and a filler. In accordance with the regulations, the yield of free carbon dioxide when using a baking powder should be at least 12%; this requirement actually sets the mandatory soda level.
Such a ratio of acid and sodium bicarbonate is considered correct, at which the reaction proceeds completely. It's called
the amount of neutralization... The proportion of acid (or acids) depends on its (their) neutralization number. As an inert filler, usually
dry starch is used... The filler provides the physical separation of the soda and acid particles necessary to prevent them from damaging reaction with each other.
There are single or double acting baking powders... A double-acting baking powder contains two acids, one of which reacts (becomes soluble) at room temperature and the other when heated. The amount of acid included in the recipe depends on the amount of soda and the number of acid neutralization. Since acids are used in the form of acidic salts, the following method has been developed to determine the neutralization number.
Neutralization number = mass of NaHCO3x100 / 100 g acid salt, (6)
Typically, the opening reaction does not affect the pH of the product, but failure to comply with the required amount of acid will change its properties and taste.
For example, excess baking soda tends to impart a soapy flavor to the product. The color of many foods is also highly dependent on the pH value.
In the bakery industry, several types of acids are used as loosening agents. Acids differ in their reaction rate at different temperatures. The properties of acids most commonly used for disintegration are shown in Table 1.
Table 1 - Properties of acidic salts, most often used as disintegrants - look at the site of the placement source, link under the spoiler.
The first salt that began to be used as a baking powder was
tartar (monopotassium salt of tartaric acid); this substance is a by-product of the wine industry. Tartar reacts easily at room temperature.
When using potassium bitartrate (tartar):
NaHCO3 + KHC4H4O6 → CO2 + KNaC4H4O6 + H2O, (7)
Since the cost of this substance is quite high, monocalcium phosphate is now widely used instead.
Monocalcium Phosphate just as readily reacts at room temperature and is widely used as a fast acting ingredient in double acting leavening agents.
There are many types on the markets
sodium acid pyrophosphates (SAPP)... They differ from each other in the reaction rate, which depends on the method of their preparation. Sodium acid pyrophosphates are widely used for the production of canned biscuits and donuts. In the manufacture of these products, special requirements are imposed on loosening, which only acidic sodium pyrofasphates correspond to.
The main problem with using them is the aftertaste.... A rather noticeable "pyrophosphate" flavor of biscuits and donuts occurs due to the exchange reaction of calcium contained in the enamel of the teeth and sodium present in disodium phosphate. The latter is formed as a result of a disintegration reaction, that is, it is the result of the activity of an enzyme that breaks down pyrophosphate. In order to limit the effect of disodium phosphate, we tried to add calcium in various forms to the composition, but these attempts made it possible to solve this problem only to some extent.
2NaHCO3 + Na2H2P2O7 → Na4P2O7 + 2CO2 + 2H2O, (
Sodium Aluminum Phosphate (SALP) it is widely used as a second (reactive at elevated temperature) acid in double-acting leavening agents, as well as in ready-made semi-finished products for the manufacture of baked products. Sodium aluminum phosphate is not only a good baking powder, but also gives strength to the finished product (the texture of the crumb is enhanced).
Sodium aluminum sulfate (SAS) SALP was widely used in disintegrants as a second acid before it was marketed and is still used in some formulations today. The main problems with using SAS are that it
weakens the crumb texture and imparts a slightly astringent flavor to the product.Dicalcium phosphate is not an acidic salt, but still it can enter into the reactions necessary for loosening.At elevated temperatures, it redistributes and gives an acidic reaction. This usually happens at such a high temperature that it makes no sense to use this salt as a disintegrant, but it does allow adjusting the pH of the final product.
Glucono-δ-lactone is a lactone that produces acid when hydrolyzed. Its use in bakery products is somewhat limited, as hydrolysis occurs over a fairly wide temperature range. This substance can also impart to foods
slightly bitter taste. The main advantage of glucono-δ-lactone is that, unlike other disintegrants, it does not form neutral salts; its main drawback is its rather high cost.
The salts formed as a result of the disintegration reaction not only have a noticeable effect on the intensity of gas formation and the amount of gas released (and in some cases on the taste of the product), but can also change the rheological properties of the product.
Divalent and trivalent ions increase its elasticity, while sulfate ions decrease it. Probably, these ions in the whipped batter provide “cross-linking” with proteins.
The reaction of sodium bicarbonate and sodium pyrophosphate (sodium acid pyrophosphate) is as follows:
Divalent and trivalent ions increase its elasticity, while sulfate ions reduce it... Probably, these ions in the whipped batter provide “cross-linking” with proteins.
A problem can arise, for example, when the bottom crust of biscuits comes off after baking, the crumb is slightly porous. In this case, the acid used acts too quickly, it is recommended to replace it with a slower one.
The reaction rate of the disintegrant can also be controlled using an acid or sodium bicarbonate with larger particles; however, it must be ensured that unreacted components do not remain in the baked product, as this can impair the taste of the product. This can happen even when using a clearly "slow" acting acid, such as sodium acid pyrophosphate.
Therefore, by using different leavening agents, the quality of the finished product can be controlled. Using multicomponent leavening agents allows you to achieve the best finished product results.
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