Wheat flour is obtained by grinding wheat with pre-cleaning and separation of shells.
The chemical composition of flour depends on the composition of wheat, flour milling and processing modes (Table. 38).
Tab.38. The chemical composition of wheat milling products in% on a dry basis (at Proskuryakov and H. O. Osipova)
|total nitrogen||Starch||Sugar common||fat||lecithin||Sterols|
The quality of flour is characterized by the following indicators: color, moisture, coarse grinding, smell, taste, acidity, protein content, carbohydrates, fat, enzymes, mineral substances, harmful and metallic impurities. Qualitative requirements for flours of grades I and II must comply with OCT / KZ SNK * 8467 / 256 and 8470 / 268, and for the highest grade, the time standards for quality indicators established in 1938.
Color flour - one of the main indicators of quality. It can be used for approximate determination of the grade of flour. High-grade flours are white with a yellowish tinge; low ones are darker and non-uniformly motley.
On flour color influenced by the following factors.
The consistency of the endosperm grain. The flour endosperm has a lighter color and the flour of the highest grades from this grain has a distinct white color. The vitreous endosperm gives the flour a darker tone and therefore it has a white color with a cream shade.
Flour Particle Size Large particles give the flour a darker tone, which is explained by the different refraction of light from large and small particles, but this difference in flour shades disappears in a uniform dough,
The presence of the crushed grain shells, which have a
dark shade compared with the endosperm. This is especially true for red grain varieties of wheat, which receive color due to the presence of red-brown pigment in the seed coat.
For prolonged storage flour acquires a lighter shade, due to oxidation by atmospheric oxygen carotenoid pigments.
Taste and smell
Flour should have a slightly sweet taste. A bitter or sour aftertaste, musty, moldy or foreign smell, indicating the ignorance of flour or the presence of impurities in it, is not allowed.
The moisture content of the flour is of great importance for the preservation of good quality flour. During the storage of flour in it the process of "breathing" takes place, in which the monosaccharides of the flour are oxidized by oxygen in the air, releasing carbon dioxide, water and heat. This process is enhanced by increasing the moisture content of the flour, which leads to the heating of the flour with the release of moisture, causing the flour to become stale and caked into lumps. Breathing flour is accompanied by losses of dry substances, which significantly increase during storage with high humidity.
If the flour with high humidity and temperature is stored in a dark and poorly ventilated warehouse, then favorable conditions are created for mold development and infection by pests: flour mite (Tyroglyphus farinae L.), flour crush (Térénia molitor Ü.), Weevil (CAL1 and ganganoria) flour ognevka (Ryralis farinalis L.).
Flour is hygroscopic and therefore its storage conditions must be well defined in order to avoid an increase in the flour moisture.
Flour stock must be maintained at relative humidity 60 — 65% and temperature 15 — 18 °.
These storage conditions are most favorable, since the equilibrium moisture content of the flour is maintained at the level of 12 — 13%.
The acidity of the flour is due to the presence of acidic phosphates of potassium and calcium, the products of the breakdown of the fat of flour - fatty acids, and also the decomposition products of the protein substances of the flour.
During the storage of flour its acidity increases due to an increase in the amount of fatty acids. When molding the flour acidity may increase due to the accumulation of organic acids, due to the activity of microorganisms.
With increasing temperature and the room humidity increases the acidity of meal,
Flour output also affects the change in acidity. Flour with higher yields during storage increases acidity more than flour with lower yields.
The acidity of flour can to some extent serve as a criterion for determining its freshness. Flour stale most often has a high acidity (6 ° and above in the mash).
Wheat grains contain minerals, and the ash elements in individual parts of the grain are unevenly distributed (Table 39).
39 Table. Ash components wheat (by E. I. Mambishu)
|Components of the grain||at %|
Shells and aleurone layer
Embryo with a shield
0,36 – 0,60
7,30 – 10,80
5,00 – 6,70
According to the content of ash in the flour can be judged on the thoroughness of separating the wheat kernels from farinaceous shells, aleurone layer and germ and thereby control the grinding process.
In addition, the ash content is one of the main objective indicators determining the grade of flour; the higher the ash content, the lower the flour grade (table 40).
40 Table. Norm ash content of flour
|flour Quality||Ash content, max%||flour Quality||Ash content, max%|
Minerals flour due to the presence of phosphorus compounds in the grain, potassium, magnesium, calcium, sodium, iron and other in much smaller quantities. phosphorus, calcium and iron to increase the nutritional value of the meal.
Along with this, a mineral impurity can be found in the flour, for example, in the form of earth stuck to the grain, or sand — due to abrasion of the millstones during the grinding process.
These impurities are undesirable in flour and their content should not exceed 0,1%.
By acting OSTam amount of pulverulent metallic impurities be not more than 3 1 mg per kg flour and Metal impurities having a plate-like or needle-like shape does not have to be contained in the flour.
Contaminants in the flour
Wheat grain may contain weed seeds, which, when milled, fall into the flour. Particular attention is paid to the presence of harmful impurities in the form of seeds of poisonous plants (gorchak, Vyazel, cockle) and cereals with a mushroom disease (ergot, smut).
The current standard is limited to the presence of harmful impurities in the flour within the following limits: smut and ergot together no more than 0,05%, bitter and lick together no more than 0,04%, cockle no more than 0,1%.
Krupnota particles of flour
Krupnota is of great importance in the production of flour confectionery products.
Education test speed largely depends on krupnoty flour particles. The larger the meal, the slower the process of swelling of the proteins gluten and dough formation.
Due to these properties, a large flour can be used where the need to limit the swelling of proteins.
In the production of sugar and lingering cookies, the swelling of gluten proteins during dough formation mainly limits sugar (to a lesser extent, fat) due to dehydrating properties. Therefore, it is possible to obtain plastic sugar dough with low humidity (17 — 19%).
A lingering dough containing less sugar and fat is obtained that is elastic and elastic due to the greater swelling of gluten proteins (moisture content 23 — 25%).
Due to the lower speed of gluten swelling compared to fine flour, coarse flour can be used to produce products according to the recipe of long varieties with a structure and properties that are no different from sugar varieties of products.
In enterprises, especially in the summer, it is often necessary to exceed the consumption of sugar within permissible limits in order to prevent the dough from being sucked. This is because with increasing room temperature and, therefore, raw materials, the speed and limit of the swelling of proteins increase, and therefore you have to add sugar to the dough to reduce the limit of swelling of proteins and thus avoid getting a test.
This leads to the fact that, along with the excessive consumption of sugar and, consequently, an increase in the cost of products, it is necessary to frequently change the technological regime, adapting to the flour and the temperature of the surrounding air,
The use of coarse flour in combination with fine flour eliminates the need to change the dosage of sugar in the production of sugar cookies.
This flour by size should comply with the following indicators: the residue on the silk sieve No. 27 no more than 5%, the pass of the sieve No. 43 no more than 15%.
Krupnota flour is determined by sieving it through a sieve of laboratory sieving Zhuravlev.
Standards for bread baking wheat flour used in the production of flour confectionery products are given in Table. 41.
41 Table. Standards krupnoty flour
|Title flour||sieve number||% to not more than||sieve number||not less B%|
Protein substances flour. (Confectioner's Handbook).
Flour proteins are divided into the following groups:
a) albumin, soluble in water and easily coagulated when heated. Wheat leukozin belongs to this group and is contained in the grain in the amount of 0,3 — 0,5%;
b) globulins, soluble in weak solutions of neutral salts. Wheat Edestin belongs to this group and is contained in the grain in the amount of 0,6 — 0,8%;
c) prolamins soluble in diluted ethyl alcohol (50 — 70%) and in weak acids and alkalis. Wheat gliadin belongs to this group of proteins;
g) glutelins are soluble in weak acids and alkalis and the precipitated during neutralization. wheat glutenin belongs to this group of proteins.
The most important are gliadin and glutenin of wheat, which contains more 75% in the total amount of nitrogenous substances of the grain.
In the presence of water, these two proteins swell and form an elastic sticky and stretching mass called gluten.
Gluten is obtained by mixing flour with water in the ratio of 2: 1 and the subsequent washing of the starch from the dough with tap water.
in chemical composition shown in Table gluten. 42.
Gliadin and glutenin are not chemically individual proteinaceous substances; they are a complex of different fractions.
Tab. 42. The chemical composition of gluten-free flours for trade in% (by V. Smirnov and H. Poulard)
|flour varieties||flour||Water in gluten||In gluten on dry matter|
|nitrogenous substances||gluten||ash||fat||nitrogenous substances||glia
|0 – 30||16,8||29,6||9,1||69,4||0,92||2,1||88,4||50,2||34,9||3,4||8,58|
|0 – 75||17,5||33,3||11,8||66,1||1,03||2,4||84,6||47,2||35,3||2,1||11,97|
|0 – 85||16,4||28,7||10,3||63,7||1,15||3,3||84,7||43,6||37,3||3,8||10,95|
|0 – 96||18,3||36,0||14,4||59,9||2,00||2,8||86,5||43,0||39,1||4,4||8,70|
For converting nitrogen to protein (nitrogenous substances) the coefficient 6,25 is used.
Water absorbing ability and its gluten fractions given in Table. 43.
43 Table. Water absorption capacity of gluten and its fractions (of. Kuhlmann AG)
|Gluten and its constituent parts||Number
|The amount of absorbed water in ml / g|
The maximum swelling of gluten occurs at 30 °. A further increase in temperature leads to a decrease in the swelling of gluten.
Along with the amount of gluten, the quality of gluten, that is, its physical properties, has a very significant effect on the properties of the dough.
Poor quality gluten has little stretch resistance, and strong quality gluten is very elastic and has a significant tensile strength. Medium quality gluten is intermediate.
Of the methods proposed for determining the colloidal and physical properties of gluten, the plastometer PL-2, which operates according to the principle of a cargo viscometer of expiration and is widely used in the baking industry, is of interest. The quality of gluten is determined by the duration of pressing out a two-gram sample of gluten through the opening of the plastometer with a cross section of 4,9 mm2 with pressure 3 kg. Moreover, the stronger the gluten, the more it resists pressing out through the opening of the plastometer and, therefore, more time is needed for pressing out gluten.
Approximate norms of PL-2 plastometer readings (according to VNIIHP) for gluten of various quality are given in Table. 44.
Proteins flour, intended for the production of flour confectionery products, the following requirements. Protracted varieties of cookies must be made from flour with a weak quality of gluten. When using flour with a strong and medium quality gluten, a long-lasting biscuit is obtained that is deformed with a non-smooth surface, often with blisters.
44 Table. Standards rheometer readings PL-2
|gluten quality||Expiration time in seconds at 20 °|
|Average||Over 27 — 30 to 60 — 90|
|strong||90 to 150 — 180|
|Very strong (korotkorvuschayasya)||150 – 180|
Good quality sugar cookies are obtained by using flour with low and medium quality gluten.
The amount of gluten flour does not have a noticeable effect on the quality of the long and sugar cookies. However, considering that a greater amount of gluten requires more water for dough formation, it is necessary to produce cookies from flour with an average content of raw gluten (27 — 30%).
Raw gingerbread should be produced from flour with a strong quality of gluten, since in this case their density is lower, the volume and rise are higher, and swelling and porosity are better than gingerbread made from flour with a weak and medium quality gluten.
The amount of gluten flour affects the quality of raw gingerbread. The optimal amount of raw gluten in flour should be 32 — 37%.
Custard gingerbread should be made from flour with an average amount of gluten of poor quality.
For the production of wafer sheets, it is necessary to use flour with a small amount of raw gluten (25 — 30%) of poor quality.
Plain biscuits should be made from flour containing 32 — 42% crude gluten of moderate quality.
For the production of dry biscuits, preference should be given to flour with a crude gluten content of about 30% of poor quality (Slavin).
For cakes such as puffs, custards, and baba, flour should be used with 38 — 40% of raw gluten of strong quality, which should ensure the formation of an elastic, well resistant to breaking dough.
For pastry-type cakes, as well as for sweet biscuits, low to medium quality flour is used with a raw gluten content from 30 to 35%.
Carbohydrates in flour are presented in the form of starch, sugars, dextrins, hemicellulose and fiber.
The strongest proportion in flour is starch (up to 80%). It is usually found in the endosperm cells of the grain and is completely absent in the aleurone layer and in the embryo. A characteristic feature of starch is its ability to swell (at 50 °) in the presence of water and then to gelatinize as the temperature rises (65 - 67,5 °).
Sugars are present in flour mainly in the form of sucrose, maltose, glucose and fructose, with sucrose being the largest amount '(up to 2%). Reducing sugars (glucose, fructose, maltose) in flour (a little, they range from 0,1 to 0,37%.
The amount of sugars in flour is of great technological importance during yeast fermentation of dough, which does not contain sugar, since in this case the gas-forming ability of flour will depend largely on the amount of "own" flour sugars, as well as sugars resulting from the hydrolysis of starch .
Hemicelluloses are contained in the shells and are alkaline soluble solids. A significant part of hemicellulose consists of pentosans.
Fiber makes up the bulk of the shells of grain and is present in flour of the highest grades in small quantities, in the lower grades - in much larger quantities.
Fats and phosphatides
Wheat grains contain a small amount of fat (2 — 3%). Its distribution in the grain is uneven: the largest number in the embryo (14,25%) and the aleurone layer and a relatively small amount in the endosperm (up to 1%). As a result, the lower grades of flour contain more fat (over 2%) as compared to the higher ones (up to 1%).
The fat of the flour consists mainly of glycerides of unsaturated acids (oleic, linoleic and linolenic) and a relatively small amount (up to 10%) of glycerides of terminal acids (stearic and palmitic).
Wheat fat has the following constants: specific gravity at 15 ° - 0,9294; refractive index — 1,4717; acid number 7,16 — 7,90; saponification number 180,83 — 181,35; iodic number 120,78 - 123,17; rhodium number 80,01 — 79,12.
During the storage of flour hydrolysis of fat occurs with the formation of free fatty acids (mainly oleic), aldehydes, ketones and hydroxy acids.
This process is especially intensive at high humidity and temperature of the flour. As a result of the hydrolysis of the fat of the flour, the acid value of the fat increases, which can serve as an indicator of the duration and storage conditions of the flour.
The grain of wheat contains phosphatides in the amount of 0,65%, which, like fats, are glycerides, but differing from them in the ester bond of phosphoric acid and nitrogenous base. According to V.S. Smirnov, the flour contains from 0,006 to 0,015% lipid phosphorus.
Flour contains various enzymes that affect the speed and direction of biochemical processes.
Among the most significant and frequent need to include the following enzymes:
a) amylolytic, consisting of two enzymes - α-amylase, hydrolyzing starch with the formation of mainly dextrins and much less maltose, and β-amylase, which turns starch mainly into maltose with a small amount of dextrins;
b) proteolytic, consisting of proteases acting on protein substances and disaggregating them without the formation of amino acids, and polypeptidases, acting on protein degradation products with the formation of amino acids.
In addition, the flour contains enzymes that cleave fats (lipase), phosphatides (phosphatase) and oxidation (oxidase, peroxidase) and reduction enzymes (catalase} and others.
The flour contains B vitamins
Vitamin B1 or aneurin is found in significant amounts in the aleurone layer and in the germ of wheat grain.
In conjunction with phosphoric acid, it forms carboxylase enzyme active group.
Wheat flour contains 1,44 — 2,24 μg of vitamin B1 on 1 g dry matter flour (1 μg is equal to 1 / 1000 mg).
vitamin B2, or riboflavin, most of all in a germ of grain (7,8 — 14,5 μg / g) and therefore flour of the highest grades contains very small amount of this vitamin. Its grain contains 0,6 — 3,7 μg / g, flour I grade 0,4 — 1,3 μg / g k in flour of the highest grade 0,3 — 0,5 μg / g.
Vitamin PP, or nicotinic acid, also belongs to the group of vitamins B and is found in significant amounts in grain and flour. So, in the wheat grain this vitamin is contained in the amount of 45 — 63 μg / g, in flour of the highest grade 10 μg / g and in flour of the I grade - 17,6 — 21,0 μg / g.
Vitamins6 (pyridexin), pentothenic acid and biotin are found in wheat grain. About 5 mg / g pyridoxine, about 13 mg / g pantothenic acid and 700 m-μg / g biotin are found in wheat.
Vitamin E is found in significant amounts in wheat germ. Flour contains this vitamin in the following amounts: in the highest grade 0,3 mg / g, in grade I — 14,6 μg / g.
The amount of vitamins in the flour grades lower than in high-grade flour.
The wheat flour no vitamins A, D and C.
Flour is usually stored in packaged form. Bags for flour made from linen, jute, hemp and cotton fabrics. Recently, bulk storage of flour in silos has been spreading.
Flour standard moisture can be stored in silos 30 days. When humidity not exceeding 13,5%, and occasional agitation flour shelf life can be increased.
The silo height should not exceed 10 — 15 m when the moisture content of the flour is no higher than 14,5%, and in case of greater humidity, the height of the flour layer in the silo should be limited to 10 m.
Storing bagged flour produced in closed warehouses, which must be dry and clean, odor-free, not infested granary pests, well isolated from rodents.
Flour is stacked in piles (200 — 250 bags) on floorings made of boards or bars of at least 10 height from the floor. If there is a wooden floor and a ventilated underground, it is allowed to lay flour directly on the floor. Between the stacks leave the aisles 0,5 m.
The most common methods of packing bags of flour - "tee" and "five". In winter, as well as dry flour is laid "five"; in the summer, as well as wet flour is usually laid "tee".
Stacking pile height depends on the time of year, humidity and state of the container flour (Table. 45).
45 Table. Height stacking flour
|Humidity flour%||Outdoor temperature in °|
|+ 10 and higher||below + 10 to 0||below 0|
|Until 14||10 bags||12 bags||14 bags|
|Over 14 to 15 incl. . . .||8||10||12|
In exceptional cases, flour may be stored under a canopy or in open areas. To protect the flour from precipitation, the stacks must be laid on 1,5 — 2 m from the edge of the shed and the space between the roof and the shed floor must be tightened with a tarpaulin.
The open area should rise above the soil level on 15 — 25 cm, it should be enclosed with a ditch for water flow.
Flour on platforms placed riot, t. E. Parallel rows, tapering towards the top, which is placed on the board or slug and thoroughly cover tarpaulin so was covered not only the top but also the sides riot.
Under adverse storage conditions and high moisture flour flour deterioration occurs. The most often observed is the self-heating of flour, which occurs due to the increased humidity and temperature of the room. As a result, the flour is caked into lumps and made stale and rancid.
When the self-warming meal is necessary to make relaying stacks with lower stacking bags and packed flour should be released from the container and passed through a large sieve.
Flour infected with granary pests must be passed through an screening machine in an isolated warehouse and gas disinsected with carbon disulfide, and the contaminated container removed.
Soybean is an annual legume that grows mostly in the People's Republic of China.
Soybean crops are conducted in the North Caucasus, Transcaucasia, Ukraine and the Far East.
Soy is distinguished by a high content of proteins, which in their usefulness are close to the proteins of meat. Along with this, soy contains a large amount of fat.
The chemical composition of soybean varies widely depending on the varietal characteristics of its, geographical and agrotechnical growing conditions.
The chemical composition of soya flour is given in Table. 46.
A characteristic feature that determines the quality of soy flour is fiber. With a decrease in the grade of soy flour in it increases the fiber content. So, in the highest grade soy flour the content of fiber is 1,85%, in grade I - 3,39% and in grade II - 4,15%.
Ash content cannot serve as an indicator that determines the quality of soy flour, as in wheat flour, since the ash content of the soybean cotyledons is higher than the ash content of the shells and germs, and therefore, the soy flour freed from the shells and the embryo has a higher ash content than soybeans.
46 Table. The chemical composition of soybean flour in% on air-dry substance (according to W. A. and S. Rusch Aksarinoy)
|Type soy flour||Water||Ash||Fat||Protein|
|Low Fat||6,17-9,80||5,68 – 7,05||0,99 – 3,40||48,87 – 56,73|
|Type soy flour||Fibre||Nitrogen-free extractives|
|Neobezzhirennaя||1,76 -4,15||6,38 -9,56||13,30-21,26|
|Low Fat||2,62 – 6,56||7,40 – 11,23||20,74 – 24,18|
Ash components of soybeans are given in Table. 47.
47 Table. The ash content of the components of soybeans
|Name of parts of the grain||% Ash in dry matter|
The composition of ash soy flour includes: 0,6% phosphorus, 0,28% calcium and 0,22% magnesium.
Soybean fat mainly consists of glycerides of unsaturated acids: oleic (26 — 27%), linoleic (55 — 57%) and linolenic (2 — 3%). The glycerides of the limiting acids in the fat (palmitic and stearic) are found in insignificant amounts. Soybean fat has a high iodine value (115,0 — 131,3).
The soy flour contains up to 2,5% of lecithin.
Soy flour contains a large amount of proteins, in the composition of which the main place is occupied by wisteria (about 80%). Up to 75, proteins are water soluble, which is important for the production of soy milk.
The carbohydrate complex of soy flour (according to the data of TsNILSOI) consists mainly of sucrose (8,49 — 11,01%), hemicellulose (4,91 — 9,16%) and cellulose.
In addition, soy flour contains a small amount of starch, dextrins, glucose and maltose.
In soy contains large amounts of vitamins A, V1 (thiamine), V2 (riboflavin), PP (niacin), pantothenic acid, biotin, choline, inositol.
According to GOST 3898-47, in the USSR, three types of soybean deodorized flour are produced: non-fatted soybean, half-defatted soybean meal cake and defatted soybean meal meal. These varieties must satisfy the following physicochemical parameters (Table 48).
Soy has an unpleasant bean flavor and peculiar smell.
The study of the nature of odorites leads to the conclusion that these substances are highly mobile unstable organic compounds, among which phenol, aldehyde, and ketone derivatives are found.
In addition, there are indications that tannins, which, under the influence of peroxidase, produce products with an unpleasant taste and odor affect the taste properties.
To remove the unpleasant legume flavor and peculiar smell, soy beans or soy flour are deodorized.
For the deodorization of soy proposed many ways, among which some deserve special attention.
Thus, Bernhard recommends steam processing of soybeans in rotating autoclaves under low pressure, followed by binning them in bins for 24 hours and drying at 80 — 90 °, after which the soybeans are ground to flour.
The following methods of soybean deodorization have been developed at the All-Union Research Institute of the confectionery industry. Soybeans are soaked in water at a temperature of about 20 ° for 16 — 24 hours before their weight increases by approximately 2,2 times. After soaking, it is recommended to keep the soybean for 45 — 60 minutes in boiling 1 — 2% salt solution, after which it is subjected to additional biochemical treatment with baker's yeast (2 — 3% pressed yeast to the weight of soybean) during 3 — 4 hours. When soy is deodorized by this method, there are losses of its dry matter in the amount of 10 — 11%.
Another way to deodorize soybean, developed by VKNII, is as follows. Soybeans are soaked in warm water.
48 Table. Physico-chemical characteristics of soybean meal
|Indicators||Type of meal|
|Humidity in%, not more than||9||9||9||9||9||9||9||9||9||9||9|
|Fat in% on absolutely dry matter||No||less||no less||No more|
|Krupnota grinding residue in%, no more on a silk sieve|
|Balance in% on sieve with metallotkannom 0,56-mm mesh, no more||2|
|Passage in%, at least through a silk sieve|
|Metal impurities in mg per kg of product 1, no more||3||3||3||3||3||3||3||3||3||3||3|
so that the temperature of the mixture of soybean and water is no higher than 42 °. 0,01 — 0,02% pepsin and hydrochloric or sulfuric acid are added to the water in such an amount that the pH of the solution corresponds to 1,8 — 2. Soybeans are kept in this 4 — 6 solution for hours, during which new portions of acid are added so that the pH of the solution does not change. After locking, the soybeans are washed with water at a temperature of 40 ° until the acid reaction disappears and dried at a temperature of 60 — 70 ° during 3 — 4 hours.
Soy is used in the confectionery industry in ground form; a prerequisite for its use is the absence of the specific taste and smell.
It is allowed to replace 5% wheat flour with the same amount of soy flour in the manufacture of biscuits and gingerbread from flour I and II grades.
In addition, the recipes of some varieties of cookies (Black Sea and Leto) and gingerbread (Autumn) use of soy flour.
In some varieties of candy (Little Humpbacked Horse, Rainbow, Amateur), toffee (Fruit, Oriental) and fatty glaze number 1 also provides for the use of soy flour.
Soy flour is a high-calorie (464 kcal per 100 g) and nutritious raw materials, which, with effective deodorization, should be widely used in the confectionery industry.
Storage soy flour
During storage, physical and chemical changes occur in the soy flour.
The moisture content of the flour is established depending on the relative humidity of the air, and the equilibrium moisture content of the flour packed in bags usually comes later, 2 — 3 weeks after storage.
During storage of flour and an increase in titratable acidity.
The acid number of fat in the flour increases significantly, and the fat of the non-deodorized soy flour has a higher acid number than the deodorized one.
In addition to the hydrolysis of fat, oxidative processes occur in soy flour during storage to form peroxide compounds, aldehydes and ketones.
Acid number of fat and reaction to aldehydes and ketones can serve as indicators of freshness soy flour.
Soy flour should be stored in dry, clean and non-contaminated granary pests warehouses, in which the relative humidity of the air 60 — 65% and temperature 15 — 18 ° must be maintained.
Zatarivatsya soy flour in bags and stacked wagon and posortno.
Soybean deodorized flour can be stored for a year without deterioration.
Soy undeodorized flour rancid in 1 — 2 of the month.
And e r m a n LY, bakery technology Pishchepromizdat, 1956.
Knyaginichev M. I., Biochemistry wheat Selkhozgiz, 1951.
Confectionery Technology, ed. prof. Rapoport AL and AL Sokolov, Pishchepromizdat, Part II, 1952.
Flour production technology, Zagotizdat, 1951.
Commodity food products, ie. 1, Gostorgizdat, 1949.
Trisvyatsky LA, Storage of grain,