Conditions and terms of storage of flour. Types, types and grades of flour

Flour is one of the products that should always be in the house. But storing it in an apartment, despite the long shelf life, is a rather complicated matter. If the basic storage conditions of the product are not observed, bugs may appear in it, and then it will no longer be possible to use it for cooking and it will have to be thrown away. In addition, living creatures can start in the neighboring cereals, tea and spices. To solve this problem, you need to know how to properly store flour at home.

1. The right purchase

Before storing flour or cereals, you need to buy it, which means you need to know how to choose an unspoiled product. If you have the opportunity to examine and feel the goods, then be sure to take a closer look at whether the flour dust has stuck together from excessive moisture, whether there are lumps or black dots in it - harbingers of future larvae and worms. But most often we take the goods in closed paper bags and have no opportunity to examine the product. One thing remains: check the integrity of the package, the absence of mold, the release date and its shelf life. If the contents spilled out a little through the poorly glued bottom of the package, then test the purchase for smell. Do you feel bitterness? This means that the raw materials were stored incorrectly for a long time.

When buying a product, pay attention to whether there are strong-smelling products, such as tea or spices, nearby. Wheat, rice, flaxseed flour and its other types will surely absorb foreign odors, which will spoil taste qualities raw materials.

2. The best packaging for the home

How to store flour or cereals at home? Many housewives, having bought, for example, flaxseed flour or semolina in paper bag, do not consider it necessary to pour it into another container. But after opening the package, store bulk products no more on paper. The best container for storing bulk food materials is a glass container with sealed lid. It can be a jar or a container. If you think such dishes are heavy, bulky and uncomfortable, you can use Plastic container with rubber gaskets on the lid for a tighter fit. They are also perfect for our purpose. Lightweight and inexpensive containers can be bought in a variety of volumes and shapes that are convenient for you.

Good for bulk storage dried fruits and mushrooms, crackers and bread linen bags, which are very popular with advanced housewives. Linen is a natural material that allows food products“breathe, which means neither your flaxseed meal nor semolina they will not grow moldy and no living creatures will start in them. They are easy to use, pleasant to the touch and take up little space.

And what to store the purchased goods in if the usual two-kilogram package is not your format? A large amount of raw materials will be well stored in linen bags or thick paper bags. Before long-term storage, be sure to dry the product on spread parchment paper.

3. Where to put the container

Knowing where to store wheat, rye or flaxseed flour is important, but not enough. Where can the product be stored? If you store a small amount, then place the container with ground grain on the lower shelves in a closed cabinet, away from specific smelling products. Store the product in the vegetable compartment of the refrigerator.

If you store a large amount of flour for future use, then the storage room should be sufficiently dark, dry and cool. The temperature should not exceed 15 degrees. It can be, for example, a pantry.
Is it possible to save raw materials on the balcony? On the glazed balcony and loggia the basis of future bakery products can be stored only in winter, when cold frosty weather sets in. Rest of the year Sun rays and dampness make it impossible to store the product here.

The healthiest whole wheat flour. It is rich in amino acids, vitamins and microelements. To maintain weight, you can opt for flaxseed flour, the consumption of which significantly improves metabolism.

4. Shelf life

Remember that the main ingredient in baking delights has an expiration date, which you should definitely be aware of. So, corn and flax flour is stored under favorable conditions from 3 to 6 months, rye - only up to six months, wheat and rice - up to 9 months. But at low temperatures the shelf life of grain ground into powder increases to 2 years.

Store bulk food properly and always delight your loved ones with delicious meals.

Introduction

Flour is a powdery product obtained by grinding grain with or without separating the bran. Chemical composition flour.

Flour contains Sahara- mainly monosaccharides (glucose, fructose) and disaccharides (maltose, sucrose). There are few sugars in flour. The higher the grade of flour, the less sugars it contains. The content of fiber and other carbohydrates also depends on the type of flour. The lower the grade of flour, the more fiber it contains. Fiber absorbs water, increasing the water absorption capacity of the flour. Of great technological importance are carbohydrate mucus (pentosans). They have the ability to strongly swell and increase the water absorption capacity of the flour.

Squirrels- the most important component flour, as its nutritional value and suitability for baking bread depend on them. Proteins in flour different varieties, are unequal. Flour proteins are of great technological importance in the preparation of dough and bread. Due to their ability to swell, they absorb the main amount of water during dough kneading, playing a leading role in its formation. At the same time, as a result of the formation of gluten, the wheat dough turns out to be elastic, elastic and extensible. During baking, denaturation of proteins occurs and a kind of skeleton of the product is formed, due to which it retains its shape.

Fats. Flour contains little fat. Unsaturated fatty acids predominate in the composition of triglycerides, so fats are easily hydrolyzed during storage of flour, which has a significant impact on the acidity and taste of flour, as well as on the properties of gluten.

Minerals. Various parts of the grain contain different amount mineral salts. So, in the endosperm of the grain of mineral salts there are few, and in the embryo and shells it is much higher. The higher the grade of flour, the less outer parts of the grain rich in mineral salts get into it, the lower the ash content of the flour. The ash content of flour is currently the main indicator that determines its commercial grade, because. ash content can be used to judge the amount of bran.

vitamins. The content of vitamins is also related to the type of flour. In the flour of the highest grades of vitamins, there are significantly less vitamins than in the lower ones, because. vitamins are contained mainly in the embryo and aleurone layer. Flour contains vitamins B, PP and E.

Enzymes. Amylases and proteinases predominate in the composition of enzymes and are of great technological importance. Flour also contains enzymes that break down fats (lipase), break down the amino acid tyrosine to form dark-colored substances.

Depending on the raw material (grain) used, flour is divided into types:

main - wheat and rye;

secondary - barley, corn and soy (can be used in baking, but in small quantities);

special purpose - oatmeal, rice, buckwheat, pea (used in the food concentrate industry);

Swelling flour (for the production of custard varieties of bread).

Depending on the intended use, wheat flour is divided into baking, pasta and general purpose. Rye flour is produced only for baking.

Soy flour is classified according to its fat content; fat-free, semi-fat and fat-free. By quality, flour is divided into commercial grades.

Wheat baking flour is produced in six grades: extra, higher, grain, first, second and wallpaper. Rye baking flour - three grades: seeded, peeled and wholemeal. Barley - two varieties: single-grade and wallpaper.

Corn - three varieties: fine grinding, coarse grinding and wallpaper.

Soybean deodorized flour, regardless of the fat content, is divided into two grades: the highest and the first.

CONDITIONS AND TERMS OF STORAGE OF FLOUR.

Flour refers to food products with a long shelf life. Mandatory storage conditions are: relative humidity of air in storage rooms not more than 70%, temperature not higher than 25°C without sudden temperature changes, compliance with the commodity neighborhood.

Storehouses should be clean, checked for barn pests, especially dark and warm corners. At long-term storage it is better to use low temperatures - about 0 ° C.

The shelf life of flour is set by the manufacturer of products at an ambient temperature not higher than 25 ° C and relative air humidity not higher than 70%. Under these conditions, they usually store:

varietal wheat flour- 6-8 months,

rye varietal flour - 4-6 months,

corn and soy non-deodorized - 3-6 months,

soy deodorized - 12 months.

Types, types and grades of flour.

Flour is a product of grain processing by grinding. Depending on the grinding, type of grain, they distinguish Various types, types and grades of flour.

Kind of flour.

The type of flour is determined by the culture from which flour is produced, this is the “ethnos” of flour, so to speak. Exists great amount types of flour: wheat, rye, oatmeal, soybean, pea, corn, buckwheat, barley, rice; there are also mixtures of grain different cultures such as rye and wheat. There is another type of flour - oatmeal.

type of flour.

The type of flour determines its purpose. Not all flour determines the main purpose of baking, an example is flour from durum varieties wheat for production pasta, or rice flour, oriental cuisine often used for breading. It does not crumble when fried and, for example, fish breaded in rice flour, does not burn. Oat flour used in the baking of cookies and the production of infant formula. From cornmeal in Moldova they cook hominy - a very thick porridge that is eaten with butter or milk or baked like the Italians do their polenta. Buckwheat flour is widely used in pancakes and infant formulas. Soy flour, with a low protein content, contains a huge supply of carbohydrates, which dramatically increases the energy value of any dish and allows unscrupulous manufacturers to deceive quality standards.

Flour type.

The grade of flour determines the quality and directly depends on the yield of flour, that is, the amount of flour obtained from a certain amount of grain. The yield of finished flour from grain is expressed as a percentage and the lower the percentage, the higher the grade of flour.

In baking and production of bakery products, wheat and rye flour is mainly used. Flour from cereals and cereals is produced both as an independent product and as a component of composite mixtures in order to enrich the composition of products with macro- and microelements, amino acids, vitamins, etc.

Let us dwell in more detail on the varieties of wheat and rye flour.

Wheat flour.

There are five main varieties of wheat flour, according to GOST 26574 "Baking wheat flour": grits, higher, first, second grades and wallpaper or four varieties according to TU 8 RF 11-95-91 "Wheat flour" of the highest, first, second grades and wallpaper .

Krupchatka- a kind of wheat flour produced from soft wheat varieties, with the addition of durum wheat. Krupchatka bears its name because it has a large section of grains;

Top grade- a kind of wheat flour from soft wheat varieties, produced by one or two varietal grindings. Premium flour consists of finely ground particles of endosperm, mainly its inner layers. It contains almost no bran and has White color with a slight creamy tint. The particle size is mainly 30-40 microns;

I grade- a kind of wheat flour from soft wheat varieties, produced by one or two varietal grindings. Flour of the first grade consists of finely ground particles of the entire endosperm and 2-3% (by weight of flour) of crushed shells and the aleurone layer. Flour particles are less uniform in size than in premium flour. Their size is mainly 40-60 microns. The color of the flour is white with a yellowish tint compared to premium flour. It contains less starch and more proteins, so more gluten is washed out of this flour than from premium flour;

2 grade- a kind of wheat flour from soft wheat varieties, produced by two or three varietal milling, with the addition of a small amount bran. The color of such flour has a yellowish or grayish tint;

Whole flour(whole grain) - produced from all types of soft wheat varieties. Wholemeal flour is obtained by single-grade wholemeal grinding, grinding the entire grain, so it contains both the endosperm and the peripheral parts of the grain. During its production, the casings are not screened out. The flour is larger, the particles are heterogeneous in size. Their size is from 30 to 600 microns and more. The color of the flour is white with a yellowish or grayish tint and clearly visible crushed shells. In terms of chemical composition, it is close to the chemical composition of grain. bran in wallpaper flour at least twice as much as in flour of the 2nd grade. Such flour contains only a small amount of gluten (about it later), but, at the same time, it contains all the useful substances of the grain and is simply a storehouse of vitamins, macro- and microelements, essential amino acids, vitamins and minerals.

Rye flour.

According to GOST 7045, there are three varieties of rye baking flour: seeded, peeled and wallpaper.

Seeded flour It is formed mainly from the endosperm of rye grain. The mass fraction of shells in it is 2-3%. The color of the flour is white with a slight grayish tint, the size of the particles is up to 200 microns. Its yield with single-grade grinding is 63%.

Peeled flour consists of endosperm and 12-15% of peripheral parts. It is larger than seeded, slightly darker. Its output with single-grade grinding is 87%.

Whole flour are made with wallpaper single-grade grinding. Grind all parts of the grain. Flour coarse, gray mass fraction shells 20-25%. Its yield is 95%.

The table shows the main indicators of the quality of a particular type of flour of two main types - wheat and rye:

Flour composition.

The baking properties and nutritional value of a particular type of flour directly depend on the chemical composition. For example, premium wheat flour is produced from the central layers of the grain endosperm, so it contains a maximum of starch, but a minimum of proteins, fats, sugars, minerals and vitamins.

The table shows the average composition of wheat and rye flour, depending on the variety:

Carbohydrates.

The first place, both in rye and wheat flour, is occupied by carbohydrates (starch, sugars, pentosans, cellulose) and proteins, the quality of the future dough directly depends on their properties. It is proteins that determine the strength of wheat flour in other countries: the more protein (proteins) in flour, the stronger it (flour).

Flour contains a variety of carbohydrates, the most important of which is starch. Starch in flour is contained in the form of grains, of various shapes and sizes, depending on the type and type of flour. The inner part of the starch grain consists of amylose polysaccharide, consisting of linear or slightly branched chains of glucose molecules connected by bonds between the 1st and 4th carbon atoms. The outer part of the starch grain is made up of amylopectin, a polysaccharide with tighter bonds of glucose.

Starch determines many qualities of the future test. Due to starch carbohydrates, dough is fermented under the action of enzymes. It is starch carbohydrates that are food for yeast, the waste product of which is carbon dioxide, loosening the dough and giving everyone's favorite holes in the baguette. In addition, starch absorbs up to 80% of the water in the dough, having a major influence on the formation of the dough. During the baking process, it is the starch that is responsible for the rise of the loaf, since when heated, the starch grains that absorb hot water, swell, increase in volume, becoming looser, thereby more susceptible to the action of amololytic enzymes.

Squirrels.

Proteins are organic macromolecular compounds consisting of amino acids. In a protein molecule, amino acids are linked together by peptide bonds. The composition of wheat and rye flour proteins includes simple proteins (proteins), consisting only of amino acid residues, and complex proteins (proteins).

The technological role of flour proteins in the preparation of bread is great. The structure of protein molecules and the physicochemical properties of proteins determine the properties of the dough, affect the shape and quality of bread. Proteins have a number of properties that are especially important for making bread. The content of proteins in wheat and rye flour ranges from 9 to 26%, depending on the type of grain and its growing conditions. Proteins are characterized by many physicochemical properties, of which the most important are solubility, the ability to swell, denaturate and hydrolyze.

The more proteins are contained in the flour and the stronger their ability to swell, the more raw gluten will be obtained, namely the presence of gluten in Russia determines the strength of the flour. A significant part of flour proteins does not dissolve in water, but swells well in it.

Rye flour proteins differ in composition and properties from wheat proteins. About half of rye proteins are soluble in water or salt solutions. Rye flour proteins have a greater nutritional value than wheat proteins (they contain many essential amino acids), but their technological properties are much lower. Protein substances of rye do not form gluten. IN rye dough most of the proteins are in the form of a viscous solution, therefore rye dough devoid of elasticity and elasticity inherent in wheat dough.

Cellulose, hemicelluloses, pentosans are classified in the group dietary fiber. Dietary fibers are found mainly in the peripheral parts of the grain and therefore they are most abundant in high-yield flour. Dietary fiber is not absorbed by the human body, so they reduce the energy value of flour, while increasing the nutritional value of flour and bread, as they accelerate intestinal motility, normalize lipid and carbohydrate metabolism in the body, and contribute to the removal of heavy metals.

Fats.

Fats are esters of glycerol and higher fatty acids. The composition of flour fats consists mainly of liquid unsaturated acids(oleic, linoleic or nolenic). The fat content in different varieties of wheat and rye flour is 0.8-2.0% per dry matter. The lower the grade of flour, the higher the fat content in it. Any fat in the dough inhibits the fermentation process.

Enzymes- substances of protein nature, capable of catalyzing (accelerating) various reactions.

The grain contains a variety of enzymes, concentrated mainly in the germ and peripheral (marginal) parts of the grain. Therefore, lower grade flour contains more enzymes than higher grade flour.

Enzymes are active only in solution, therefore, when storing dry grain and flour, their action is almost not manifested. After kneading semi-finished products, many enzymes begin to catalyze the decomposition reactions of complex flour substances. The activity with which the complex insoluble substances of flour are decomposed into simpler water-soluble substances under the action of its own enzymes is called autolytic activity (autolysis - self-decomposition).

Over time, the activity of enzymes does not stop, thereby explaining the meaning of my favorite long-term fermentation of the dough. With prolonged fermentation, due to the action of enzymes, the rheological properties of the dough are improved, which entails the baking of better and tastier bread.

The autolytic activity of flour is an important indicator of its baking properties. Both low and high autolytic activity of flour adversely affect the quality of dough and bread. It is desirable that the autolytic process of decomposition of proteins and dough starch occurs at a certain, moderate rate. In order to regulate autolytic processes in the production of bread, it is necessary to know the properties of the most important flour enzymes that act on proteins, starch and other flour components. But for this you need a whole chemical laboratory, and where to get it.

Physical properties of flour

Lesser sorption capacity flour does not exclude the development of various physiological processes in it. The total moisture content in the flour may be quite sufficient for their occurrence and development. Of great importance in this case is the uneven distribution of moisture in individual particles of flour and in its mass as a whole.

The methods used in practice for determining the moisture content of flour characterize only the total amount of hygroscopic moisture in a given sample, but not the distribution of this moisture in individual flour particles. Being heterogeneous, they differ from each other in chemical composition, size, shape and structure. All this leads to the fact that the sorption properties of individual flour particles and even their individual sections are different.

If the flour particles are moistened or are in hygroscopic equilibrium with the environment, the highest humidity is observed on their surface. During desorption, moisture simultaneously moves from the inner layers of the particle to the outer.

The uneven distribution of moisture in each flour particle, even with a low average moisture content (14 ... 15.5%), creates conditions for the development of microbes on the surface of the particles.

During storage under production conditions, due to changes in temperature and relative humidity, the humidity of individual layers of flour also changes, which can lead to the formation of active microbiological foci.

Thus, the humidity of the stored flour and the distribution of moisture in it depend on the state of the surrounding atmosphere, the initial properties of the flour and the conditions of its storage.

Flour is also able to absorb vapors of other substances and gases, and therefore it can acquire odors that are unusual for it. When storing, fumigating and transporting flour, this must be taken into account.

Observations of the dynamics of cereal moisture during production storage and in laboratory conditions showed that the hygroscopicity of cereals is at the level of the grain mass or somewhat less than it. Groats obtained from grains with flower films and fruit shells of a porous structure, as a rule, have less hygroscopicity than the grains of this crop (rice, pearl barley, semolina). Millet usually has a higher equilibrium moisture than millet, from which it is obtained. With long-term storage of cereals, the moisture content reaches equilibrium.

Thermophysical properties. Like grain mass, flour, bran and cereals have low thermal conductivity and thermal diffusivity. Heat transfer in the mass of flour by air convection is observed to a lesser extent than in the grain mass. This is due to the specific structure of its porosity. Due to the poor thermal conductivity of flour, it is advisable to cool it before storing it both in silos for bulk storage and in stacks for storage in bags.

The movement of moisture in flour in the presence of a temperature difference creates the prerequisites for the formation of condensation moisture in certain areas and the emergence of active microbiological foci.

Among the thermophysical properties of flour, its heat capacity is of great importance. It is taken into account when kneading the dough to immediately obtain the temperature necessary for fermentation.

Chemical composition of flour

The chemical composition of flour depends on the composition of the grain from which it is made, and on its variety. The higher the grade of flour, the more starch it contains. The content of other carbohydrates, as well as fat, ash, proteins and other substances, increases with a decrease in the grade of flour.

Features of the quantitative and qualitative composition of flour determine its nutritional value and baking properties.

Carbohydrates

The carbohydrate complex of flour is dominated by higher polysaccharides (starch, fiber, hemicellulose, pentosans). In not in large numbers flour contains sugar-like polysaccharides (di- and trisaccharides) and simple sugars (glucose, fructose).

Starch. Starch, the most important carbohydrate in flour, is contained in the form of grains ranging in size from 0.002 to 0.15 mm. The size, shape, swelling capacity and gelatinization of starch grains are different for flour. various kinds. The size and integrity of starch grains affects the consistency of the dough, its moisture capacity and sugar content. Small and damaged grains of starch are saccharified faster in the process of making bread than large and dense grains.

Starch grains, in addition to starch itself, contain a small amount of phosphoric, silicic and fatty acids, as well as other substances.

The structure of starch grains is crystalline, finely porous. Starch is characterized by a significant adsorption capacity, as a result of which it can bind a large amount of water even at a temperature of 30 ° C, i.e. at the dough temperature.

The starch grain is heterogeneous, it consists of two polysaccharides: amylose, which forms the inside of the starch grain, and amylopectin, which makes up its outer part. The quantitative ratios of amylose and amylopectin in the starch of various cereals are 1:3 or 1:3.5.

Amylose differs from amylopectin in its lower molecular weight and simpler molecular structure. The amylose molecule consists of 300-800 glucose residues forming straight chains. Amylopectin molecules have a branched structure and contain up to 6000 glucose residues. When starch is heated with water, amylose passes into a colloidal solution, and amylopectin swells, forming a paste. Full gelatinization of flour starch, in which its grains lose their shape, is carried out at a ratio of starch and water of 1: 10.

Subjected to gelatinization, starch grains increase significantly in volume, become loose and more pliable to the action of enzymes. The temperature at which the viscosity of the starch jelly is the highest is called the starch gelatinization temperature. The gelatinization temperature depends on the nature of the starch and on a number of external factors: the pH of the medium, the presence of electrolytes in the medium, etc.

The gelatinization temperature, viscosity and rate of aging of starch paste in different types of starch is not the same. Rye starch gelatinizes at 50-55°C, wheat starch at 62-65°C, corn starch at 69-70°C. Such features of starch are of great importance for the quality of bread.

The presence of sodium chloride significantly increases the gelatinization temperature of starch.

The technological significance of flour starch in the production of bread is very high. The water absorption capacity of the dough, the processes of its fermentation, the structure of the bread crumb, taste, aroma, porosity of bread, and the rate of staleness of products largely depend on the state of starch grains. Starch grains bind a significant amount of moisture during dough kneading. The water absorption capacity of mechanically damaged and small grains of starch is especially high, since they have a large specific surface area. In the process of fermentation and proofing of the dough, part of the starch under the action of 3-amylase

saccharified, turning into maltose. The formation of maltose is necessary for the normal fermentation of the dough and the quality of the bread.

When baking bread, starch gelatinizes, binding up to 80% of the moisture in the dough, which ensures the formation of a dry, elastic bread crumb. During storage of bread, starch paste undergoes aging (syneresis), which is the main cause of staleness of bread products.

Cellulose. Cellulose (cellulose) is located in the peripheral parts of the grain and therefore is found in large quantities in flour of high yields. Wholemeal flour contains about 2.3% fiber, and wheat flour of the highest grade contains 0.1-0.15%. Fiber is not absorbed by the human body and reduces the nutritional value of flour. In some cases, a high fiber content is useful, as it accelerates the peristalsis of the intestinal tract.

Hemicelluloses. These are polysaccharides belonging to pentosans and hexosans. In terms of physicochemical properties, they occupy an intermediate position between starch and fiber. However, hemicelluloses are not absorbed by the human body. Wheat flour, depending on the variety, has a different content of pentosans - the main component of hemicellulose.

Flour of the highest grade contains 2.6% of the total amount of grain pentosans, and flour of the II grade contains 25.5%. Pentosans are divided into soluble and insoluble. Insoluble pentosans swell well in water, absorbing water in an amount exceeding their mass by 10 times.

Soluble pentosans or carbohydrate mucus give very viscous solutions, which, under the influence of oxidizing agents, turn into dense gels. Wheat flour contains 1.8-2% mucus, rye flour - almost twice as much.

Lipids

Lipids are called fats and fat-like substances (lipoids). All lipids are insoluble in water and soluble in organic solvents.

Fats. Fats are esters of glycerol and high molecular weight fatty acids. In wheat and rye flour different varieties contains 1-2% fat. The fat found in flour has liquid consistency. It consists mainly of glycerides of unsaturated fatty acids: oleic, linoleic (mainly) and linolenic. These acids have a high nutritional value, they are credited with vitamin properties. Hydrolysis of fat during storage of flour and further conversion of free fatty acids significantly affect the acidity, taste of flour and the properties of gluten.

Lipoids. Flour lipoids include phosphatides - esters of glycerol and fatty acids containing phosphoric acid combined with some nitrogenous base.

The flour contains 0.4-0.7% of phosphatides belonging to the group of lecithins, in which choline is the nitrogenous base. Lecithins and other phosphatides are characterized by high nutritional value and have a great biological significance. They easily form compounds with proteins (lipo-protein complexes), which play an important role in the life of every cell. Lecithins are hydrophilic colloids that swell well in water.

As surfactants, lecithins are also good food emulsifiers and bread improvers.

Pigments. Fat-soluble pigments include carotenoids and chlorophyll. The color of carotenoid pigments in flour is yellow or orange, and chlorophyll is green. Carotenoids have provitamin properties, as they are able to turn into vitamin A in the animal body.

The best known carotenoids are unsaturated hydrocarbons. When oxidized or reduced, carotenoid pigments turn into colorless substances. This property is the basis for the process of bleaching wheat flour, which is used in some foreign countries. In many countries, flour bleaching is prohibited, as it reduces its vitamin value. The fat-soluble vitamin of flour is vitamin E, the other vitamins of this group are practically absent in flour.

Minerals

Flour consists mainly of organic substances and a small amount of mineral (ash). The mineral substances of the grain are concentrated mainly in the aleurone layer, shells and embryo. Especially a lot of minerals in the aleurone layer. The content of minerals in the endosperm is low (0.3-0.5%) and increases from the center to the periphery, so the ash content is an indicator of the flour grade.

Most of the minerals in flour consist of phosphorus compounds (50%), as well as potassium (30%), magnesium and calcium (15%).

In negligible amounts contains various trace elements (copper, manganese, zinc, etc.). The iron content in the ashes of different types of flour is 0.18-0.26%. A significant proportion of phosphorus (50-70%) is presented in the form of phytin - (Ca - Mg - salt of inositol phosphoric acid). The higher the grade of flour, the less minerals it contains.

Enzymes

Cereal grains contain a variety of enzymes, concentrated mainly in the germ and peripheral parts of the grain. In view of this, high-yield flour contains more enzymes than low-yield flour.

Enzyme activity in different batches of flour of the same variety is different. It depends on the conditions of growth, storage, modes of drying and conditioning of the grain before grinding. Increased activity of enzymes was noted in flour obtained from unripe, sprouted, frost-bitten or bug-damaged grain. Drying grain under a hard regime reduces the activity of enzymes, while storing flour (or grain) it also decreases somewhat.

Enzymes are active only when the humidity of the environment is sufficient, therefore, when storing flour with a moisture content of 14.5% and below, the action of enzymes is very weak. After kneading, enzymatic reactions begin in semi-finished products, in which hydrolytic and redox flour enzymes participate. Hydrolytic enzymes (hydrolases) decompose complex flour substances into simpler water-soluble hydrolysis products.

It is noted that proteolysis in wheat dough is activated by substances containing sulfhydryl groups and other substances with reducing properties (amino acid cysteine, sodium thiosulfate, etc.).

Substances with opposite properties (with the properties of oxidizing agents) significantly inhibit proteolysis, strengthen gluten and the consistency of wheat dough. These include calcium peroxide, potassium bromate and many other oxidizers. The effect of oxidizing and reducing agents on the process of proteolysis is already felt at very low dosages of these substances (hundredths and thousandths of a % of the mass of flour). There is a theory that the effect of oxidizing and reducing agents on proteolysis is explained by the fact that they change the ratio of sulfhydryl groups and disulfide bonds in the protein molecule, and possibly the enzyme itself. Under the action of oxidizing agents, disulfide bonds are formed due to the groups, which strengthen the structure of the protein molecule. Reducing agents break these bonds, which causes the gluten and wheat dough to weaken. The chemistry of the action of oxidizing and reducing agents on proteolysis has not been finally established.

The autolytic activity of wheat and especially rye flour is the most important indicator of its baking value. Autolytic processes in semi-finished products during their fermentation, proofing and baking should proceed with a certain intensity. With increased or decreased autolytic activity of flour, the rheological properties of the dough and the nature of the fermentation of semi-finished products change for the worse, and various bread defects occur. In order to regulate autolytic processes, it is necessary to know the properties of the most important flour enzymes. The main hydrolytic flour enzymes are proteolytic and amylolytic enzymes.

Proteolytic Enzymes. They act on proteins and their hydrolysis products.

The most important group of proteolytic enzymes are proteinases. Papain-type proteinases are found in grains and flours of various cereals. The optimal indicators for the action of grain proteinases are pH 4-5.5 and temperature 45-47 ° C -

During dough fermentation, grain proteinases cause partial proteolysis of proteins.

The intensity of proteolysis depends on the activity of proteinases and on the susceptibility of proteins to the action of enzymes.

Proteinases of flour obtained from grain of normal quality are not very active. Increased activity of proteinases is observed in flour made from sprouted grains and especially from grains affected by the tortoise bug. The saliva of this pest contains strong proteolytic enzymes that penetrate the grain when bitten. During fermentation, the initial stage of proteolysis occurs in the dough prepared from flour of normal quality without any noticeable accumulation of water-soluble nitrogen.

During the preparation of wheat bread, proteolytic processes are regulated by changing the temperature and acidity of semi-finished products and adding oxidizing agents. Proteolysis is somewhat inhibited by table salt.

Amylolytic enzymes. These are p- and a-amylases. p-Amylase was found both in germinated grains of cereals and in grains of normal quality; a-amylase is found only in sprouted grains. However, a significant amount of active α-amylase was found in rye grain(flour) of normal quality. a-Amylase refers to metalloproteins; its molecule contains calcium, p- and a-amylases are found in flour mainly in a state associated with protein substances and are split after proteolysis. Both amylases hydrolyze starch and dextrins. The most easily decomposed by amylases are mechanically damaged grains of starch, as well as gluten starch. The works of I. V. Glazunov established that 335 times more maltose is formed when dextrins are saccharified with p-amylase than when starch is saccharified. Native starch is hydrolyzed by p-amylase very slowly. p-Amylase, acting on amylose, converts it completely into maltose. When exposed to amylopectin, p-amylase cleaves maltose only from the free ends of the glucoside chains, causing hydrolysis of 50-54% of the amount of amylopectin. The high molecular weight dextrins formed in this process retain the hydrophilic properties of starch. α-Amylase cleaves off branches of the glucosidic chains of amylopectin, converting it into low molecular weight dextrins that are not stained with iodine and lack the hydrophilic properties of starch. Therefore, under the action of a-amylase, the substrate is significantly liquefied. Then dextrins are hydrolyzed by a-amylase to maltose. The thermolability and sensitivity to the pH of the medium are different for both amylases: a-amylase is more thermally stable than (3-amylase), but more sensitive to substrate acidification (lowering pH). p-Amylase is most active at a medium pH of -4.5-4, 6 and a temperature of 45-50 ° C. At a temperature of 70 ° C, p-amylase is inactivated. Optimum temperature a-amylase 58-60 °C, pH 5.4-5.8. The effect of temperature on the activity of a-amylase depends on the reaction of the medium. With a decrease in pH, both the temperature optimum and the temperature of α-amylase inactivation decrease.

According to some researchers, flour a-amylase is inactivated during bread baking at a temperature of 80-85 ° C, however, some studies show that in wheat bread a-amylase is inactivated only at a temperature of 97-98 °C.

The activity of a-amylase is significantly reduced in the presence of 2% sodium chloride or 2% calcium chloride(in an acidic environment).

p-Amylase loses its activity when exposed to substances (oxidizing agents) that convert sulfhydryl groups into disulfide ones. Cysteine ​​and other drugs with proteolytic activity activate p-amylase. Weak heating of the water-flour suspension (40-50 ° C) for 30-60 minutes increases the activity of flour p-amylase by 30-40%. Heating to a temperature of 60-70 °C reduces the activity of this enzyme.

The technological significance of both amylases is different.

During dough fermentation, p-amylase saccharifies some of the starch (mainly mechanically damaged grains) to form maltose. Maltose is necessary to obtain loose dough and normal quality of products from varietal wheat flour (if sugar is not included in the product recipe).

The saccharifying effect of p-amylase on starch increases significantly during starch gelatinization, as well as in the presence of a-amylase.

As a rule, flour refers to those products that it is customary to stock up in an apartment or house for a long time. But proper storage flour in the apartment - this task is not as simple as it might seem at first glance. Indeed, flour has a long shelf life, but improper storage conditions almost always cause unpleasant living creatures to appear in the flour, which makes the entire stored stock unusable. And the most unpleasant thing is that flour or cereals that are stored in bags not far from that bag or other container with flour, where pests have already started, will also be spoiled in a very short period of time. Alas, until now, not everyone knows how to properly store flour for a long time so that such "evil spirits" do not get to it, and even the owners of large-scale commercial stocks of flour do not always do it right.

How to properly store flour

Storage temperature

Favorable temperature - from +5 to +15 ° C. At temperatures below 0 ° C, flour can be stored for 2 years or more.

First of all, before storing flour, you should carefully inspect it at the time of purchase. Of course, every experienced seller knows how to store flour for a long time so as not to risk their own money, because if bugs appear in bags of flour, you will have to get rid of more than a dozen kilograms of the product and suffer considerable losses. Ideally, flour should be stored in whole bags or packages at low humidity in a store warehouse. All that the buyer can do to protect himself from spoiled flour is to check if the flour in the bags has stuck together from moisture, and if there are black dots, worms or bugs in it. Unpleasant, but often flour is sold in opaque or paper packaging which makes such verification impossible. Well, in this case, it remains only to check the integrity of the package, the release date and specifically how much flour of this manufacturer can be stored.

Our great-grandmothers also knew how to store flour in an apartment in order to protect its pests. A glass jar is the best way to store flour in an apartment, our ancestors thought so and were absolutely right. Tightness is what will protect any product from unwanted living creatures. Many will say that the shape and size of glass containers do not always allow you to economically use the space in the apartment, but today there is huge selection sealed containers from various materials, that are great alternative glass container. It is entirely possible to place flour for long term storage in such a glass or plastic container fitted with rubber seals to keep the lid tight. It should be noted that metal containers are not suitable for storing flour, since they are not leak-tight.

Where to store flour

How long to store flour

Wheat flour is stored for 6–8 months, rye flour for 4–6 months, and at low temperatures, flour can be stored for up to two years or more.

It is also important to know where to properly store flour, because the appearance of insects is not all that can spoil it. Firstly, the container with flour should not be in direct sunlight. Secondly, it has no place where dampness prevails. Dark, dry and cool place – ideal conditions For long storage flour in the apartment. A small bag of salt, a clove of garlic, Bay leaf or chili peppers in a container where the flour will be stored for more than one month. It doesn’t matter if flour is stored in bags in a warehouse or in a special container in an apartment, the main thing is that it is not subjected to sudden changes in temperature. It should not be placed near it products with intense aromas, including coffee, spices, tea, and cleaning products.

It is also important to know not only what to store flour at home, but also how long you can do it. Every product has an expiration date and should be adhered to. So, under reasonable conditions light flour can be stored in bags or containers for up to one year, and light - up to 9 months. For flour coarse grinding typical storage for six months. But homemade flour should be used as soon as possible, namely within two weeks.

Flour is one of those products that housewives try to stock up. Someone likes to cook pastries, and someone just bought a lot of flour for a promotion in a supermarket or at a fair. Having saved money on the price, it is now very important to keep the whimsical product safe and sound. This is not easy to do. It absorbs moisture and odors, and often becomes food for insects and rodents.

Therefore, in order to avoid such troubles with flour, it should be stored according to certain rules.

At home, you can save it only if you take into account all its properties. The main parameters on which the duration of storage depends are temperature regime and humidity. It is also equally important to decide on the place where the product will be contained.

Flour is a product of grinding cereal crops. The most common is wheat flour. The taste of the wheat product remains virtually unchanged throughout the entire storage period. At the same time, flour from flax, almonds and corn can change them beyond recognition. Flaxseed and almond add to pastries original taste and aroma. These species are recommended to be stored in the refrigerator, previously placed in an airtight container.

How to determine if a product has become unusable

A quality product that has been properly stored, must be dry, crumbly, odorless, mold and bugs.

What is flour stored in

Most often it is stored in the same paper bag. in which it was purchased. Paper is a good storage material, and pouring flour into another paper bag is not practical. Caring hostesses prefer to sew linen bags. If the bag is torn, pour it into glass jar with tight lid.

For her, as a rule, determine a separate shelf in the kitchen. It quickly absorbs foreign odors, and from dampness it forms lumps. Therefore, there should be no sharp, unpleasant odors in the room, and there should be a sink or other source of water nearby.

Larger volumes should preferably be dried beforehand. To do this, the product is laid out in a thin layer on paper and kept near the stove or heater.

Many housewives doubt can flour be stored in a plastic container. Food-grade plastic is absolutely harmless, in addition, it perfectly protects the product from moisture during long-term storage. Can be adapted for storage plastic bottles with a wide neck, as well as mayonnaise buckets or any other containers made of polymers. Remember to wash and dry thoroughly before using.

Some housewives prefer to sew a linen bag. If it is pre-soaked in salt water and dry, the product will be stored longer, and insect pests and fungi will not be afraid of it.

Flour storage conditions

If you decide to keep it in the refrigerator, then keep in mind that the shelf life will be limited.

• For rye is less than five months.
• Deodorized soy and corn - eleven months.
• For wheat, no more than eight.
• Not deodorized soy and corn are stored no more than four months.

As a rule, if the temperature rises, then these indicators also change.

Wheat flour is stored at a temperature not lower than five degrees for six months. For corn, soy and rye, the shelf life at low temperature is reduced to three months.

Let's figure it out how to store flour in a high-rise apartment. If you have a glazed balcony, you can store it there, but only in winter. In summer, it is undesirable to keep the product on the balcony, as the sun's rays and dampness will spoil it.

Permissible humidity is 70%. Further increase in humidity leads to the formation of lumps. Fifteen degrees is considered the most favorable temperature for storage. This product does not tolerate sudden changes, due to which a fungus appears inside the product.

Bugs and midges

To prevent midges or bugs, follow some rules and use folk remedies. How to store flour so that bugs do not start:

• Store the product in cloth bags soaked in salt.
• Mosquitoes don't like the smell of mint. To scare them away, just put a few mint chewing gums on the surface of the jar.
• You can get rid of bugs with garlic. Add a few cloves directly to the jar and close the lid.
• Any metal object is lowered into the container. It can be a fork, spoon or a large coin.
• Bay leaf is considered safe and effective tool from midges. Despite its aroma, the flour does not absorb its smell at all.
• They do not tolerate midges and the smell of calendula. If you put a few dried calendula buds in a bag, then the insects will not approach it.

Flour that is stored for a long time is occasionally checked. She is picked up and examined. If it is damp, it is laid out in a thin layer on clean paper, and after a while it is collected and repackaged.

If the bugs are still wound up don't rush to get rid of it. It can be heated in the oven, and then transferred to a dried and clean container, previously rubbed with vinegar. Experienced housewives advise wiping the shelf with vinegar, on which the product was infected with midges.

Sometimes, even with all carefully observed storage rules, the product deteriorates. If you notice lumps or bark on the surface, then it is better to get rid of it. In most cases, it is not possible to reanimate it, so you should not spoil the pastries poor quality product, as well as expose yourself and your family to the danger of poisoning.

Attention, only TODAY!

Flour can be called one of the oldest discoveries. Rarely is a meal complete without bread. Yes, and pies, gingerbread, pretzels and buns, try to bake without flour, even the most diligent housewives cannot do it. Good - it has practically no taste, so a little bit sweet. But rancid, but stale can ruin pastries and an inveterate culinary specialist. How to store flour so that the dough from it turns out magnificent, and the bread is delicious? Is it possible to store it on the balcony or in the refrigerator so that the bugs do not start? Now I'll tell you.

Flour is grains of plants ground into powder. Wheat, buckwheat, rice, corn and soy are used. The most popular, perhaps, is wheat, it is produced in several varieties:

• The most useful - from whole grains, retains almost all the substances inherent in the culture: amino acids, trace elements and vitamins. It is low in gluten and calories.
• Flour of the second grade - gray shade, with big amount dietary fiber. Baking from it has a special bread spirit.
• The first grade also retains a certain amount useful substances and vitamins.
• High-calorie flour products. But thanks to the special processing of cereals, it has good baking characteristics.

By the way, good premium wheat flour with a slightly noticeable creamy hue.

Production storage

Before the flour reaches our home, it goes through a long period of preparation. First, the grain on the threshing equipment is converted into powder. Varieties are determined by the coarseness of the grinding. Then comes First stage storage, where gas exchange processes take place: with the access of oxygen, the respiration of milled grain particles and microorganisms occurs. Interestingly, at the same time, the flour brightens, the amount of gluten increases, and its maturation begins.

During this period, in the process of breathing, the temperature rises and moisture accumulates, therefore, in storage facilities, they strictly monitor that the degree does not rise above 20 Celsius and with the help special equipment maintain humidity no more than 60%.

In production, two methods of storage are used. In small warehouses - in bags, which are loaded in rows of several pieces. In such barns, ventilation equipment is installed, preventive measures rodent control, bugs and other pests are detected.

Large volumes are placed in the whole complex of equipment for bulk storage. It includes silo systems, bunkers, level sensors and more. After maturation and with container and bulk methods, the temperature in storage facilities is maintained at zero degrees in winter and summer. Under such conditions, the shelf life of flour is two years.

Choose by color, taste, smell

Flour is present on the shelves in packages of different weights. Conveniently, everyone can buy as much as they need in the near future or in the future. But it is difficult to check the quality of packaged flour. If it is sold in a transparent bag, which is rare, you can visually check it for the presence of food bugs and impurities, make sure there are no lumps. But it's hard to taste the taste.

When choosing flour in paper containers, we won’t be able to evaluate its appearance, color in the store, but it’s easy to smell it. You have probably noticed that flour bags have a not very pleasant property of spilling the contents through a poorly glued bottom. Let's take advantage of this and test for smell: bitter speaks of long-term improper storage. Of course, the flour should not be raw, the presence of mold is unacceptable.

Pay attention to the commodity neighborhood. Nearby there should be no products with an intense smell: spices, tea, fish.

We store at home

Mistresses know - flour must be bought for the future. She has a property, ends at the wrong moment, in the midst of cooking culinary masterpiece for home. Therefore, they are wondering how to properly store flour at home?

At home, many people use the highest quality wheat flour, but it will be useful to know how much other types are stored. Rye - about 4-6 months, corn - from 3-6, rice - no more than 10. Wheat flour manufacturers have determined the shelf life of flour: 12 months at a temperature not higher than 25 degrees, after which it loses its qualities.

If the amount is small, you can leave the flour in a consumer paper bag and store in the refrigerator to avoid bugs. In no case can you put it on top of the container plastic bag, under it favorable conditions are formed for the development of a fungal infection. A vegetable drawer is considered a safe place in the refrigerator; it protects against odors and temperature changes when the door is opened.

In a small apartment it is difficult to find an extra place to place products purchased for the future. Therefore, lovers of buying with a large margin use a balcony at home instead of a pantry. It's not bad if it's glazed. Even better, store not on the balcony, but on the loggia, since it is protected from wind, dampness and temperature changes are not felt so much.

You can store flour on the balcony in winter, when frost sets in. Dry it and pour it into a glass container; you should not use polypropylene bags in winter. Equip closed cabinets for cans on the balcony. In frosty winter, they are not afraid of moisture, rodents, or insects. In other seasons, the balcony is an unfortunate place for storage: in summer due to the heat, in spring and autumn due to humidity.

Your brownie.