Fundamentals of food technology study manual

Figure 15 
Each fiber, in turn, consists of the finest threads called collagen fibrils or 
fibrils. Collagen fibers branch and become thinner or thicker. Thus, a network of 
fibers connecting certain organs is formed. Collagen fibers swell intensively in 
acetic acid, increase in size and slightly change their structure. When marinating 
fish, the fiber mass increases. As the temperature rises in fresh water, collagen 
fibers are destroyed. In this case, collagen turns into gluten - the substance that 
forms the basis of glue. With special treatment, collagen fibers are strengthened, 
lose their ability to swell, and this is the basis for the production of leather from 
fish skin. Epithelial tissue in the fish body covers the entire surface of the skin, the 
entire inner surface of the intestine, covers blood and lymph vessels. It is made up 
of epithelial cells that do not have a membrane, but have a nucleus and protoplasm. 
The part of the protoplasm of the cell facing the outside is sharply compressed. 
These compressed parts of the cells fit tightly together and form a dense barrier 
against the entry of various foreign bodies. The protoplasm of neighboring cells is 
interconnected by bridges, which causes contraction and dense arrangement of 
cells. The space between the cells can change by increasing or decreasing, which 
regulates the exchange process of the fish body with the environment. Epithelial 
tissue is a semi-permeable film that does not contain blood and lymph vessels. 
Epithelial tissue directly under the cut there is a connective tissue film, with the 
help of which the epithelial tissue is in contact with the muscles or other organs. 
Nervous tissue consists of special nerve cells located in the brain and spinal cord, 
and countless nerve fibers are connected to the surface of the fish's body and to all 
the tissues and organs of the fish, as a result of which all the reactions of living fish 
respond to both. . It is strictly regulated by external and internal irritation. 
innumerable nerve hairs are attached both to the surface of the fish's body and to 
all the tissues and organs of the fish, so that all the reactions of the living fish 
respond to both. It is strictly regulated by external and internal irritation. 
innumerable nerve hairs are attached both to the surface of the fish's body and to 
all the tissues and organs of the fish, so that all the reactions of the living fish 
respond to both. It is strictly regulated by external and internal irritation. 
Chemical composition of fish 

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92 
Fish has elemental and molecular chemical composition. The chemical 
composition of elements shows the composition of individual chemical elements in 
the fish body. To date, about 60 chemical elements have been found in the fish 
body. Elements found in fish in large amounts (up to 0.01%), usually 
macroelements (oxygen, hydrogen, carbon, nitrogen, calcium, phosphorus, sulfur, 
etc.), in relatively small amounts (less than 0.01%) are called lgan elements.), - 
trace elements. Molecular chemistry shows the composition and quantitative ratio 
of 14 individual chemical compounds in fish. Knowledge of the molecular 
chemical composition of fish is necessary to evaluate its nutritional value and to 
choose the most rational methods of its use and processing. When evaluating fish 
as an industrial raw material, the water content of the fish (or individual parts of its 
body), crude protein or protein, the total amount of nitrogenous substances called 
fat, and the total amount of minerals are taken into account. It is determined 
separately for a more complete assessment of the nutritional properties of fish, the 
content of proteins and non-protein nitrogenous substances, fatty acids and amino 
acids, as well as vitamins and the most important minerals (phosphorus, potassium, 
calcium, iodine, etc.). Characterization of Fish Tissue Chemicals Fish tissue is 
composed of many different chemicals, the most interesting of which are proteins, 
non-protein nitrogenous substances, fats and fat-like substances, minerals, 
enzymes, vitamins, carbohydrates and water. Protein is the most biologically 
important and the most complex chemical structure of organic substances that 
make up living organisms, including fish. Proteins form the basis of tissues 
involved in the construction of fish body organs. Proteins are nitrogen-containing 
substances of high molecular weight, found mainly in cells in a colloidal state. 
This physicochemical state of protein substances is characterized by instability, 
dependence on changes in environmental conditions. Various physical (heating, 
ultrasound, high pressure, ultraviolet and ionizing radiation, etc.) and chemical 
(some organic and inorganic substances) factors can cause protein denaturation, 
that is, disruption of the molecular structure, which is accompanied by a change 
will come. Solubility in water and salt solutions, etc. After the addition of various 
salts, proteins can precipitate from the solution. Separation of protein from solution 
is called salting out. Unlike denaturation, salting is not accompanied by deep 
changes in the structure of the protein molecule and the loss of the protein's ability 
to dissolve in water again after the salt is removed from the solution. When 
preserving fish by salting, fish meat proteins must be salted. According to the 
elemental composition, proteins are characterized by the presence of carbon, 
oxygen and hydrogen, as well as nitrogen and rings, and often phosphorus. The 
amount of carbon, oxygen, hydrogen and nitrogen in different proteins varies 
within relatively small limits. Nitrogen content ranges from 15 to 17.6% (average 
16%). The total protein content of fish is determined by multiplying the chemically 
determined nitrogen content by a factor of 6.25, since 100:16 = 6.25. hydrogen and 
nitrogen in different proteins change within relatively small limits. Nitrogen 
content ranges from 15 to 17.6% (average 16%). The total protein content of fish is 
determined by multiplying the chemically determined nitrogen content by a factor 
of 6.25, since 100:16 = 6.25. hydrogen and nitrogen in different proteins change 

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93 
within relatively small limits. Nitrogen content ranges from 15 to 17.6% (average 
16%). The total protein content of fish is determined by multiplying the chemically 
determined nitrogen content by a factor of 6.25: 100:16 = 6.25. hydrogen and 
nitrogen in different proteins change within relatively small limits. Nitrogen 
content ranges from 15 to 17.6% (average 16%). The total protein content of fish is 
determined by multiplying the chemically determined nitrogen content by a factor 
of 6.25, since 100:16 = 6.25. hydrogen and nitrogen in different proteins change 
within relatively small limits. Nitrogen content ranges from 15 to 17.6% (average 
16%). The total protein content of fish is determined by multiplying the chemically 
determined nitrogen content by a factor of 6.25: 100:16 = 6.25. hydrogen and 
nitrogen in different proteins change within relatively small limits. Nitrogen 
content ranges from 15 to 17.6% (average 16%). The total protein content of fish is 
determined by multiplying the chemically determined nitrogen content by a factor 
of 6.25, since 100:16 = 6.25. hydrogen and nitrogen in different proteins change 
within relatively small limits. Nitrogen content ranges from 15 to 17.6% (average 
16%). The total protein content of fish is determined by multiplying the chemically 
determined nitrogen content by a factor of 6.25: 100:16 = 6.25. hydrogen and 
nitrogen in different proteins change within relatively small limits. Nitrogen 
content ranges from 15 to 17.6% (average 16%). The total protein content of fish is 
determined by multiplying the chemically determined nitrogen content by a factor 
of 6.25: 100:16 = 6.25. hydrogen and nitrogen in different proteins change within 
relatively small limits. Nitrogen content ranges from 15 to 17.6% (average 16%). 
The total protein content of fish is determined by multiplying the chemically 
determined nitrogen content by a factor of 6.25: 100:16 = 6.25. 
Review questions. 
10. 
The composition of the meat. 
11. 
Main quality indicators of meat. 
12. 
Factors affecting the composition and quality of milk. 
13. 
Basics of Prostokvasha preparation. 
14. 
Types of ice creams and basics of production. 
15. 
Types of fruit preserves. 
16. 
Types of canned vegetables. 
17. 
Chemical composition of fish? 
18. 
Fish body structure? 
19. 
Basic" words and phrases. 
Milk, pasteurization, microflora, drip, kefir, prostokvasha, acidophilic milk, 
ice cream, sour cream, cottage cheese, butter, cheese. Cooling, freezing, salting