Animal fats

In animals, most of the fat is part of the adipose tissue , which is located mainly under the skin (subcutaneous fat) and in the omentum , where it forms soft elastic pads between the organs. Fats protect the internal organs of animals from mechanical damage and, being poor heat conductors, help maintain a constant body temperature regardless of changes in the temperature of the environment, therefore, in cold climates, the subcutaneous fat layer reaches a significant thickness. For animals, fats serve as an important energy depot.

The chemical composition and properties of animal fats vary depending on the type of animal, although chemically all animal fats are triglycerides of higher fatty acids , i.e. esters of glycerol and carboxylic acids having from 6 to 26 carbon atoms in the molecules. In addition to triglycerides, animal fats also contain phosphatides , cholesterol , dyes, vitamins A ( retinol ), D ( calciferol ), E ( tocopherol ), F ( essential fatty acids ). ^{[1] [2]}

In terrestrial mammals, fats are usually solid, although in bones and hooves they are often liquid. Their composition is dominated by triglycerides of saturated acids - palmitic , sometimes stearic , making up most often 40-60%. Also, a small amount of myristic acid is found in them; of unsaturated acids - linoleic acid (in pig fat up to 6%), linolenic (up to 18% in horse fat ), oleic . Significant amounts of ruminant fats (cattle and small cattle) contain positional isomers of transoleic acids (mainly vaccine acid ). Hexadecenic acids, as well as unsaturated acids C ₂₀ -C ₂₂ are present in fats of terrestrial vertebrates only in an amount of up to 1-2%. ^[one]

The milk fats of various higher animals, including cows , are solid and consist of oleic triglycerides (26–34%), palmitic (24–26%), myristic (8–17%), stearic (4–8%) and linoleic ( 0.5-1%) acids. A significant amount of lower saturated (C ₄ –C ₁₀ ) and monounsaturated (C ₁₀ –C ₁₄ with a double bond in the 9–10 position) fatty acids is also present. ^[one]

The composition of bird fats is slightly different from that of terrestrial vertebrates. In bird oil , although it is solid, palmitic and stearic acids are practically absent, and the main components are triglycerides of oleic (40–45%) and linoleic (10–20%) and saturated acids (about 25%). ^[one]

Amphibian and reptile fats are usually liquid. Chemically, they contain large quantities of monounsaturated fatty acid triglycerides with a number of atoms from C ₁₆ to C ₁₈ (mainly oleic), which comprise 50-60% of the total content. Also, their composition includes up to 10% of polyunsaturated acids C ₂₀ –C ₂₂ . Saturated fatty acids (mainly palmitic) are only about 25%, although in the fats of some reptiles (crocodile, python) their content is increased to 30%. ^[one]

Freshwater fish fats are liquid and very close in composition to amphibian and reptile fats, differing from them in the high content of hexadecenoic acid (up to 30%) and C ₂₀ –C ₂₂ acids (about 15%). ^[one]

The fats of marine fish and mammals under normal conditions are liquids. The main components (from 40 to 65%) of these fats are triglycerides of monounsaturated fatty acids with 16 and 18 carbon atoms. Specific to these fats is a high content (from 20 to 40%) of polyunsaturated fatty acids with 20 and 22 carbon atoms. There are also unsaturated acid triglycerides containing from 14 to 24 carbon atoms. The content of saturated acids (from C ₁₄ to C ₁₈ ) is usually in the range of about 20%, and most of them are palmitic acid . ^[1] One of the most common fats in this category is cod liver oil, which was actively introduced in the USSR.

Animal fats are classified by: ^[3]

• types of animals - fats of terrestrial mammals, fats of birds, fats of amphibians and reptiles, fats of freshwater fish, fats of marine fish and mammals;
• types of animals - pork fat, beef fat, lamb fat, mink fat, chicken fat, fish oil, whale oil, etc.
• the source of receipt is subcutaneous (fat), body fat, bone fat, liver fat, etc.
• consistency - hard, soft and liquid fats
• grade - fat of the highest, first, second and third grade
• quality - deeply refined fat, refined fat, refined fat, crude fat, technical fat
• Intended use - edible fats, feed fats, medical fats, cosmetic fats and technical fats.
• the method of production - separation fat (milk fats, butter and egg butter), wet waste fat (chicken fat, duck fat, goose fat, etc.), dry waste fat (lard, beef fat, etc.), boiled away fat (low grade bone fat), vibroextraction fat (bone fat), extraction fat (technical fats), alkaline fat (fats for the soap industry), acid fat (industrial fats), etc.

Animal fats are obtained by dry or wet melting, digestion, extraction (hot water, steam, organic solvents), vibroextraction, pressing , separation , treatment with chemicals ( alkalis , acids ). ^[3]

The raw materials for the production of animal fats are lard , omentum , skins , mezra , bones , perinephric, cardiac and hepatic fat, fat trimmings, fat from the stomachs, intestines, internal organs, etc.

Animal fats are widely used as food ( lard , butter , lard , etc.) and components for food production. Animal fats are used for the preparation of medicines, cosmetics and detergents, are part of various biological additives, lubricants, materials, etc. Only about a third of the fats produced all over the world are used for technical purposes.

According to the WHO, the saturated fatty acids, of which animal fats mostly consist, should make up no more than 10% of the human diet (by energy value) ^[4] . EFSA (European Union) notes that saturated fatty acids are synthesized by the body and does not establish recommended levels of consumption ^[5] . The Russian methodological recommendations found that “the intake of saturated fatty acids for adults and children should not exceed 10% of the calorie intake of the daily diet” and it is noted that a high intake of saturated fatty acids is an important risk factor for the development of a number of diseases, including diabetes, obesity cardiovascular disease ^[6] .

A lack of fat in food can also lead to poor health, as they are involved in the formation of a number of hormones in the human body.

• Lipids
• Fats
• Fatty acid
• Glycerol
• Lanolin
• Spermaceti
• Vegetable fats

• Animal fats // Big Russian Encyclopedia. Volume 10. - M. , 2008. - S. 99-100.
• Tyutyunnikov B.N. Chemistry of fats / B.N. Tyutyunnikov, Z. I. Bukhstab, F.F. Gladkyi et al. - 3rd ed., Revised. and add. - M .: Kolos, 1992 .-- 448 p.
• Bezzubov L.P. Chemistry of fats. - 3rd ed .. - M .: Food industry, 1975. - 280 p.
• Paronyan V.K. Technology of fats and fat substitutes. - M .: Light and food. pr-t, 2004 .-- 352 p.