Most often, saturated fatty acids are included in the composition. Unsaturated fatty acids in cosmetology. The need for saturated fatty acids is increasing

Fats are such macronutrients that are needed for a good nutrition of people. Each person's diet should include a variety of fats, each of which plays a role. They are part of all cells of the body and are necessary for the absorption of certain vitamins, ensuring thermoregulation, normal functioning of the human nervous and immune systems. There are saturated and unsaturated fatty acids in our body, and if the latter bring great benefits, the former are considered to be harmful. But is it really so, what role do saturated fats play in our body? We will consider this question today.

NLC - what is it?

Before considering the role of saturated fatty acids (SFAs), we learn what they are. EFAs are solids that melt at high temperatures. They are most often absorbed by the human body without the participation of bile acids, therefore they have a high nutritional value. But excess saturated fat is always stored in the body in reserve. EFAs give the fats they contain a pleasant taste. They also contain lecithin, vitamins A and D, cholesterol, saturate cells with energy.

For the past thirty years, it has been generally accepted that the content of saturated fatty acids in the body causes great harm to it, as it contributes to the development of diseases of the cardiovascular system. Thanks to new scientific discoveries, it became clear that they do not pose a danger, on the contrary, they have a good effect on the activity of internal organs. They also take part in thermoregulation, improve the condition of hair and skin. Even cholesterol is vital for the human body, as it takes part in the synthesis of vitamin D and hormonal processes. With all this, the body should have moderate amounts of saturated fatty acids. Benefits and harms will be discussed below.

Benefits of EFA

Saturated (marginal) fats are needed by the human body in the amount of fifteen grams per day. If a person does not receive the required number of them, then the cells will receive them by synthesis from other food, which will lead to an unnecessary load on the internal organs. The main function of saturated fatty acids is to provide energy to the entire body. In addition, they take part in the synthesis of hormones, the formation of testosterone and estrogen, membrane cells, fat layer to protect internal organs, and also normalize the protective functions of the body.

Lack of saturated fatty acids in the body

Insufficient intake of EFAs in the body can adversely affect its development. So, quite often in this case there is a decrease in body weight, disruption of the hormonal and nervous systems, the condition of the skin and hair. Over time, women may become infertile.

Harm

Some EFAs of animal origin are directly associated with the occurrence of severe inflammatory diseases. The risk increases especially when acids enter the human body in large quantities. So, the use of large portions of fats can cause an acute inflammatory process, unpleasant sensations occur within a short period of time after eating. It is also possible to accumulate cholesterol in large quantities, which is dangerous for the cardiovascular system.

An excess of SFA in the body

Excessive intake of SFA can also adversely affect its development. In this case, there is an increase in blood pressure, disruption of the cardiovascular system, the appearance of kidney stones. Over time, excess weight accumulates, cardiovascular diseases develop, and cancerous tumors develop.

What should be consumed?

First of all, you need a balanced diet that will be saturated with fatty acids. Useful foods rich in SFAs - eggs, fish and organ meats - are most preferable. In the daily diet, fatty acids should be allocated no more than ten percent calories, that is, fifteen or twenty grams. The best option is considered to be the use of fats, which are part of products that have a large number of useful properties, such as seaweed, olives, nuts, fish and others.

Natural butter is considered a good choice; lard is recommended to be consumed in salted form in small quantities. Refined oils, as well as their substitutes, bring the least benefit. Unrefined oils cannot be heat treated. In addition, you need to remember that you can not store fats in the sun, in the open air and in the light.

Basic EFAs

1. Propionic acid (formula - CH3-CH2-COOH). It is formed during the metabolic breakdown of fatty acids having an odd number of carbon atoms, as well as some amino acids. In nature, it is found in oil. Since it prevents mold and some bacteria from growing, propionic acid, whose formula we already know, is often used as a preservative in the manufacture of foods that people consume. For example, in bakery production it is used in the form of sodium and calcium salts.
2. Butyric acid (formula CH3-(CH2)2-COOH). It is one of the most important, it is formed in the intestines in a natural way. This fatty acid contributes to the self-regulation of the intestine, and also supplies energy to the epithelial cells. It creates such an acidic environment in which conditions become unfavorable for the development of pathogenic microflora. Butyric acid, the formula of which we know, has an anti-inflammatory effect, helps to stop the development of cancer cells, and increases appetite. It also helps to stop metabolic disorders, increases local immunity.
3. Valeric acid (formula CH3-(CH2)3-COOH). It has a mild antispasmodic effect. Like oil, it activates the motility of the colon, affecting the nerve endings of the intestine and stimulating smooth muscle cells. Acid is formed as a result of the metabolism of microorganisms in the colon. Valeric acid, the formula of which was given above, occurs as a result of the activity of bacteria that make up the intestinal microflora.
4. Caproic acid (formula CH3-(CH2)4-COOH). In nature, this acid can be found in palm oil, animal fats. Especially a lot of it in butter. It has a detrimental effect on many pathogenic bacteria, even those that are resistant to antibodies. Caproic acid (the formula above) plays an important role for the human body. It has anti-allergic activity, improves liver function.

• severe diseases of the respiratory system;
• great physical activity;
• in the treatment of the digestive system;
• pregnancy and lactation;
• in the cold season, as well as people who live in the Far North;
• some diseases of the heart and blood vessels.

For quick assimilation, fats must be consumed with vegetables, herbs and herbs. It is best to use natural products that contain them, as well as having most of the useful components in their composition.

Sources of SFA

Most saturated fatty acids are found in foods that are of animal origin. It can be meat, fish, poultry, milk and cream, lard, beeswax. EFAs are also found in palm and coconut oils, cheeses, confectionery, eggs, and chocolate. People who lead a healthy lifestyle and watch their figure need to include saturated fats in their diet.

Summing up

Saturated and unsaturated fatty acids are the main sources of energy for the human body. They are important for the structure and development of cells and come from food of animal origin. Such fats have a solid consistency that does not change at room temperature. Lack and excess of them adversely affects the body.

In order to have good health, you need to consume about fifteen or twenty grams of saturated acids per day. This will replenish energy costs and not overload the body. Nutritionists recommend replacing harmful fatty acids found in fried meat, fast food, confectionery with dairy products, sea fish, nuts, and more.

It is necessary to constantly monitor not only the quantity, but also the quality of food consumed. Proper nutrition helps to improve well-being and health in general, increase productivity, and overcome depression. Thus, it is impossible to divide fats into “good” and “bad”, they all play an important role in the development and structure of the body of each of us. You just need to be more careful about the composition of your daily diet and remember that health problems arise due to a combination of factors, as well as a person’s lifestyle, so you should not be afraid of fats, both saturated and unsaturated.

But it also has other important functions: supplying the body with essential fatty acids (some of which are essential) and fat-soluble vitamins A, D and E. Fats form the lipid barrier of our skin, preventing moisture from evaporating and protecting the skin from drying out. Fat helps the body use proteins and carbohydrates efficiently. Sufficient fat content is necessary for good brain activity, concentration, memory.

But fat is different for fat, and the world of fat is so diverse and rich that you can get confused and confused. There are animal and vegetable fats (oils), solid and liquid, refractory and fusible.

So which fats are good for us and which ones are bad? - you ask. So the question cannot be asked. Both the harm and the benefits of fats depend only on their amount in the diet and combination. All natural fats and oils are mixtures of saturated, mono- and polyunsaturated fats. Any conditionally “healthy” fat contains a small amount of harmful fats, while any “harmful” fat contains useful ones.

Fats (otherwise triglycerides) belong to the class of lipids, and are natural organic compounds of esters of glycerol and fatty acids. But already these fatty acids are divided into: Saturated and unsaturated .

If there is at least one free carbon bond in a fatty acid molecule that is not bonded to hydrogen, it is an unsaturated acid; if there is no such bond, then it is saturated.

Saturated fatty acids in large quantities (up to 50% of the total mass) are found in solid animal fats. The exceptions are palm and coconut oils - despite their vegetable origin, their fatty acids are saturated. Saturated acids - butyric, acetic, margaric, stearic, palmitic, arachidic, etc. Palmitic acid is one of the most abundant fatty acids in animal and plant lipids. In animal fats and cottonseed oil, this acid makes up a quarter of all fatty acids. The most rich in palmitic acid (almost half of the total fatty acids) is palm oil.

Unsaturated fatty acids are found mainly in liquid vegetable oils and seafood. In many vegetable oils, their content reaches 80-90% (in sunflower, corn, linseed,). Animal fats also contain unsaturated acids, but their amount is small. Unsaturated include: palmitoleic, oleic, linoleic, linolenic arachidonic and other acids. There is also such a subtlety, unsaturated fatty acids, in the molecule of which there is one free carbon bond, are called monounsaturated, those that have two or more of these bonds are polyunsaturated.

Monounsaturated fatty acids are not indispensable, since our body is able to produce them. The most abundant of the monounsaturated fatty acids, oleic acid, is found in high amounts in olive oil, avocado oil, and peanut oil. This type of acid is believed to help lower blood cholesterol levels.

Polyunsaturated fatty acids (omega-6 acid complex) –
contained in sunflower oil, soybean oil, vegetable margarine.

Polyunsaturated fatty acids (omega-3 acid complex) . In terms of usefulness, they are in the first place, as they have a wide effect on various body systems: they positively affect cardiac activity, eliminate depression, prevent aging, reduce cognitive and mental abilities with age, and have a host of other useful qualities. They belong to the so-called "essential" fatty acids, which the body cannot synthesize on its own and must be supplied with food. Their main source is sea fish and seafood, and the further north the fish lives, the more omega-3 acids in its fat. Similar fatty acids are found in some plants, nuts, seeds, and oils derived from them. The main one is alpha-linolenic acid. There is a lot of it in rapeseed, soybean oils, linseed and camelina oils. They should not be cooked, but should be added to salads or taken as a dietary supplement. A completely vegetable omega-3 acid cannot replace marine: only a small part of it is converted in our body into the same acids that are found in fish.

Fats we choose

Comparing the most common fatty foods, we can be surprised to see that vegetable oils are ahead of both butter and lard in terms of calories, and olive oil contains almost no polyunsaturated fatty acids.

Sunflower oil (omega-6 acids). The most traditional vegetable oil in our latitudes. Contains a lot of polyunsaturated fatty acids, but too little omega-3 fats. This is its main disadvantage.
Total fat content - 98%
Saturated Fat - 12 g
Monounsaturated - 19 g
Polyunsaturated 69 g of which: omega-6 - 68 g; omega-3 - 1 g
Calorie content - 882 kcal

Olive oil (omega-9).
Total fat content - 98%
Saturated Fat - 16 g
Monounsaturated -73 g
Polyunsaturated - 11 g, of which: omega-6 - 10 g; omega-3 - 1 g
Calorie content - 882 kcal
The percentage of polyunsaturated acids in it is small, but it contains a huge amount of oleic acid. Oleic acid is present in plant and animal cell membranes and contributes to maintaining the elasticity of arteries and skin. It is stable at high temperatures (so olive oil is good for frying). Yes, and it is absorbed better than others. Olive oil is well tolerated even by people suffering from digestive disorders, diseases of the liver and gallbladder. Moreover, such patients are even recommended to take a spoonful of olive oil on an empty stomach - this has a slight choleretic effect.

Flaxseed oil (source of omega-3 acids). An ideal source of rare in the normal diet and the most valuable omega-3 fats. Used as a dietary supplement, 1 tablespoon per day.
Total fat content - 98%
Saturated Fat - 10 g
Monounsaturated - 21 g
Polyunsaturated - 69 g including: omega-6 - 16 g; omega-3 - 53 g
Calorie content - 882 kcal

Butter. Real butter contains at least 80% milk fat.
Total fat content - 82.5%
Saturated Fat - 56 g
Monounsaturated - 29 g
Polyunsaturated - 3 g
Cholesterol - 200 mg
Calorie content - 781 kcal
Contains vitamins (A, E, B1, B2, C, D, carotene) and lecithin, which lowers cholesterol levels, protects blood vessels, stimulates the immune system, and helps fight stress. Easily digestible.

Salo.
Total fat content - 82%
Saturated Fat - 42 g
Monounsaturated - 44 g
Polyunsaturated - 10 g
Cholesterol - 100 mg
Calorie content - 738 kcal
Pork fat contains valuable polyunsaturated arachidonic acid, which is generally absent in vegetable oils. It is part of cell membranes, is part of the enzyme of the heart muscle, and also participates in cholesterol metabolism. Moreover, in terms of the content of unsaturated fatty acids, lard is far ahead of butter. That is why the biological activity of fat is five times higher than that of butter and beef fat.

Margarine.
Total fat content - 82%
Saturated Fat - 16 g
Monounsaturated - 21 g
Polyunsaturated - 41 g
Calorie content - 766 kcal
Replaces butter, does not contain cholesterol. It has a high content of unsaturated fatty acids. If margarine contains a low content of trans fats (soft margarine), which are formed in the process of partial hydrogenation (hardening) of liquid oils, then its dietary qualities are good enough to replace butter with it.

The only definitively unhealthy fats are trans fats! Independent research confirms the link between diets high in trans fats and coronary heart disease. In 1994, trans fats were found to be responsible for about 30,000 deaths from heart disease in the United States each year.

So what fats and oils to choose (since you can’t do without them)? Nutritionists have not yet come to a consensus on how much cholesterol (and it is also vital) and fatty acids a healthy person should receive. So - more variety, use the full natural potential of fats, but do not overdo it with the amount. Everything is good in moderation!

Post in 4 parts, about saturated and unsaturated fats, about harmful and healthy oils, about trans fats, about the role of fats in the human body. The material about useful and harmful oils will not be entirely in line with the traditional presentation.

Fats in the human body play the role of a source of energy, and are also a material for the construction of living cells in the body. They are dissolve a number of vitamins and serve as a source of many biologically active substances.

Fats enhance the taste of food and make you feel full longer. With a lack of fats in our diet, such disorders in the state of the body as changes in the skin, vision, kidney disease, weakening of immunity mechanisms, etc. can occur.

In experiments conducted on animals, it has been proven that an insufficient amount of fat in the diet contributes to a reduction in life expectancy.

Fats (fatty acids) are found in plant and animal fats. They are divided into two types, depending on the chemical structure and molecular bonds, rich and unsaturated fatty acid . The latter are also divided into two types - monounsaturated and polyunsaturated fats.

1. UNSATURATED FATTY ACIDS

Unsaturated fatty acid are fatty acids that contain at least one double bond in the chain of fatty acid molecules. Depending on saturation, they are divided into two groups:

• monounsaturatedfatty acids containing one double bond


• polyunsaturatedfatty acids containing more than one double bond

Of the unsaturated fatty acids, the most biologically important are polyunsaturated fatty acids, namely the so-called essential fatty acids (vitamin F).

This is first of all linoleic (Omega 6 polyunsaturated fatty acids) and linolenic (Omega 3 polyunsaturated FA); also highlight Omega 9 acids, such as oleic is a monounsaturated fatty acid.

Omega-3 and Omega-6 unsaturated fatty acids are essential (i.e., vital) components of food products that our body cannot synthesize itself.

Both types of unsaturated fats are predominantly found in plant foods.These acids are considered more suitable for a healthy diet than saturated fatty acids. . In fact, some of them have the ability to lower cholesterol and blood pressure, thereby reducing the risk of heart disease.

Linoleic acid, oleic acid, myristoleic acid, palmitoleic acid and arachidonic acid are some of the unsaturated fatty acids.

Unsaturated fatty acids are found in all fats. In vegetable fats, their content, as a rule, is higher than in animal fats (although there are exceptions to this rule among vegetable and animal fats: solid palm oil and liquid fish oil, for example).

The main sources of unsaturated fatty acids and especially indispensable ones for humans are olive, sunflower, sesame, rapeseed oil, fat contained in fish and marine mammals.

FOODS CONTAINING MONOUNSATURATED FATTY ACIDS

olive oil, olives

Sesame oil

rapeseed oil
peanut butter, peanut

avocado fruit

nuts almonds

cashew nuts
pistachio nuts
nuts hazelnuts

FOODS CONTAINING POLYUNSATURATED FATTY ACIDS

corn oil

sunflower oil, sunflower seeds
soybean oil
salmon, mackerel, herring, sardines, trout, tuna, red caviar, shellfish (lots of Omega-3)

flaxseed, linseed oil (lots of omega-3s)

sesame seeds, sesame oil

soybeans, tofu

walnuts (lots of omega-3s)
wheat germ, their oil

BENEFITS OF UNSATURATED FATTY ACIDS

Unsaturated fatty acids (FA) are monobasic fatty acids in the structure of which there are one (monounsaturated) or two or more (polyunsaturated fatty acids, PUFA for short) double bonds between adjacent carbon atoms. Their synonym is unsaturated fatty acids. Triglycerides composed of such fatty acids are called, respectively, unsaturated fats.

There are several health benefits of unsaturated fatty acids. Foods containing monounsaturated or polyunsaturated fats are considered healthier than those containing saturated fatty acids.

The fact is that molecules rich fatty acids entering the blood tend to bond with each other , that leads to the formation of cholesterol plaques in the arteries of the circulatory system. In its turn, unsaturated Fats are made up of large molecules that do not build compounds in the blood. This leads to the unimpeded passage of blood through the arteries.

The main advantage of unsaturated fats is the ability to reduce the level of "bad" cholesterol and triglycerides in the blood. , resulting in a reduced chance of heart disease such as strokes and heart attacks.

Of course, it is almost impossible to eliminate all saturated fats from the diet, but many of them can be replaced with unsaturated fats.

For example, switching to olive oil when added to food (but not cooked) can greatly reduce your intake of saturated fat.

These dietary oils contain fat-soluble vitamins such as vitamin A, D and E which are essential for maintaining health.
vitamins A and E are antioxidants and help support the immune system so we stay healthy. They also help in blood circulation and prevent the formation of cholesterol plaques in the arteries.

Vitamin D is essential for the growth and development of bones and muscles.

BENEFITS OF UNSATURATED FATTY ACIDS:

• have an antioxidant effect


• have an anti-inflammatory effect


• reduce blood pressure


• reduce the risk of certain cancers


• improve the condition of hair and skin


• improve blood flow (prevention of blood clots)

Compared to saturated fatty acids, the pattern for melting point in unsaturated (unsaturated) it is the opposite, the more fat contains unsaturated fatty acids, the lower its melting point. Thus, if you have an oil that remains liquid even in the refrigerator, at a temperature of 2-6 ° C, you can be sure that it is dominated by unsaturated (unsaturated) fats.

It is very important that the fats consumed in food are fresh, that is, not oxidized.

Unsaturated oils themselves, as well as culinary products prepared with their use, go rancid during long-term storage, which is strongly felt in taste.

AT stale or overheated fats accumulate harmful substances , which serve as irritants of the gastrointestinal tract, kidneys, affect metabolic disorders. In dietary nutrition, such fats are strictly prohibited.

Therefore, in order to increase the shelf life of products in the confectionery industry, unfortunately, such oils are often replaced by oils with a low content of unsaturated fatty acids. A particularly dangerous trend is the use of hydrogenated fats (margarine) containing harmful trans fatty acids (trans fats) , which are much cheaper than natural oils, they also significantly increase the risk of cardiovascular disease.

Consumption norms for unsaturated fatty acids have not been established, however, it is believed that their caloric content in the general diet should normally be about 10%-30%, or in another approach - the total amount of fat from all foods consumed during the day is calculated as 1 gram per 1 kg of weight person.

It should be noted that monounsaturated fatty acid can be synthesized in the body from saturated fatty acids and carbohydrates. Therefore, they are not classified as essential or essential fatty acids.

With dietary nutrition, the qualitative and quantitative composition of fats can change. A reduced amount of fat is recommended for pancreatitis, atherosclerosis, hepatitis, diabetes, exacerbation of enterocolitis, and obesity.

When the body is depleted and during the recovery period after prolonged illnesses, injuries, on the contrary, it is recommended to increase the daily fat intake to 100-120 grams.

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2. SATURATED FATTY ACIDS

Saturated (or saturated fatty acids) are monobasic fatty acids in the structure of which there are no double bonds between adjacent carbon atoms. The absence of double or unsaturated bonds significantly reduces the reactivity (ability to combine with other molecular structures) of saturated fatty acids, that is, to participate in the biochemical processes of the body.

The biological role of saturated fats is much less diverse than that of unsaturated fats.

In foods, these substances are found in the composition of fats of both animal and vegetable origin.

The content of saturated fatty acids in animal fats is usually higher than in vegetable fats. In this regard, a clear pattern should be noted:The more saturated fatty acids a fat contains, the higher its melting point. That is, if we compare sunflower and butter, it immediately becomes clear that solid butter has a much higher content of saturated fatty acids.

An example saturated vegetable oil palm oil serves, the benefits and harms of which are actively discussed in modern society.

An example unsaturated animal oil is fish oil.

There are also artificial saturated fats obtained by hydrogenation of unsaturated fats. Hydrogenated fat is the basis of margarine, hard palm oil, they are the most harmful.

FOODS CONTAINING SATURATED FATTY ACIDS

The most significant representatives of saturated fatty acids are

stearic acid:

in lamb fat, its content reaches 30%,
in vegetable oils - up to 10%;

palmitic acid:

in palm oil is 39-47%,
in cow's cream - about 25%,
soy - 6.5%,
and in lard - 30%.

Other representatives of saturated fatty acids are lauric, myristic, margarine, capric and other acids.

The biological role of saturated fatty acids is that they are for the human body are, first of all, source of energy. They are also, along with unsaturated take part inbuilding cell membranes, hormone synthesis,transfer and assimilation of vitamins and microelements.

Having little adipose tissue, that is, little saturated fat in the body, women not only suffer from infertility at reproductive age much more often, but also endure menopause more difficult, suffering from illness and stress due to hormonal imbalances.

On the other hand, the harm of excess adipose tissue, that is, obesity, is also beyond doubt. In modern conditions of physical inactivity and overeating, a person should strive to reduce saturated fatty acids in his diet - the energy value of a person’s diet today, as a rule, is above the norm,

a essential fatty acids for building cell membranes can be synthesized by the body (provided that sufficient energy content of the diet is observed).

Excessive consumption of saturated fat is one of the most important risk factors for obesity, diabetes, cardiovascular and other diseases. Consumption rates for saturated fats have not been established, but it is believed that their energy value in the diet should not exceed 10% of the total amount of fat.

However, in harsh climatic conditions, for example, in the Far North, the need for energy increases dramatically, so it is necessary to introduce more fats into the diet, including saturated fatty acids - the most energy-rich component.

If unsaturated fats are healthier than saturated fats in terms of nutrition, then in the field of cooking, the opposite is true: it is better to cook food on animal fats, that is, on saturated.

When frying food in vegetable oil, the double bonds of unsaturated fatty acids will undergo intense oxidation with the formation of carcinogens that cause cancer.

The most important non-food application of saturated fatty acids is soap making. The sodium and potassium salts of these compounds form the basis of all types of soap. Actually, soap is obtained by saponification of the corresponding saturated fats.

Fats to Eliminate 100%

trans fats

Trans fats are formed during the industrial hardening of liquid vegetable oils.Trans fats are found in confectionery, chips, popcorn, fish sticks, industrial cutlets, ketchups, mayonnaise, french fries, whites, chebureks, refined vegetable oil (regular refined sunflower, corn oil, which is included in the cooking of almost all families), in purchased pastries, in cholesterol-free cheeses, in margarine and in spread.

Trans fats are associated with a high risk of cardiovascular disease becausethey increase bad cholesterol (LDL) and lower good cholesterol (HDL) and cause inflammation and obesity .

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VISUAL GRAPHIC MATERIALS

Once again about how fats and oils are used by the body, and what their deficiency and excess leads to; how many fats and oils are contained in 100 grams of certain foods:

What foods contain saturated, unsaturated fats, trans fats:

Which foods contain "bad fats" that need to be reduced in the diet, and "good fats" to be included in the diet. The "saturated fats" listed in the column are coconut, palm oil - they mean their hydrogenated forms (non-hydrogenated palm and coconut oil do no harm):

Which foods contain harmful trans fats, a more detailed diagram:

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All materials and oils and fats in my two blogs with my daughter can be found here:

About influence TRANS FAT on health, in particular, contained in palm oils found in industrial foods, you can readand

You can read about the properties of margarines; about healthy oils and butter; about harmful oils. These four materials in a very non-trivial presentation, still little known, very modern, which we also adhere to (irina_co, culinarium) .

- Coconut and palm oil - representatives of medium chain triglycerides in the world of vegetable oils and fats , about the importance of their use in sports and dietary nutrition.

Over 200 fatty acids have been found in nature, which are part of the lipids of microorganisms, plants and animals.

Fatty acids are aliphatic carboxylic acids (Figure 2). In the body, they can be both in a free state and serve as building blocks for most classes of lipids.

All fatty acids that make up fats are divided into two groups: saturated and unsaturated. Unsaturated fatty acids having two or more double bonds are called polyunsaturated. Natural fatty acids are very diverse, but have a number of common features. These are monocarboxylic acids containing linear hydrocarbon chains. Almost all of them contain an even number of carbon atoms (from 14 to 22, most often found with 16 or 18 carbon atoms). Fatty acids with shorter chains or with an odd number of carbon atoms are much less common. The content of unsaturated fatty acids in lipids is usually higher than that of saturated ones. Double bonds are typically between 9 and 10 carbons, are almost always separated by a methylene group, and are in the cis configuration.

Higher fatty acids are practically insoluble in water, but their sodium or potassium salts, called soaps, form micelles in water that are stabilized by hydrophobic interactions. Soaps have the properties of surfactants.

Fatty acids are:

- the length of their hydrocarbon tail, the degree of their unsaturation and the position of double bonds in fatty acid chains;

– physical and chemical properties. Typically, saturated fatty acids are solid at 22°C, while unsaturated fatty acids are oils.

Unsaturated fatty acids have a lower melting point. Polyunsaturated fatty acids oxidize faster in the open air than saturated ones. Oxygen reacts with double bonds to form peroxides and free radicals;

Table 1 - The main carboxylic acids that make up lipids

In higher plants, there are mainly palmitic acid and two unsaturated acids - oleic and linoleic. The proportion of unsaturated fatty acids in the composition of vegetable fats is very high (up to 90%), and of the limiting ones, only palmitic acid is contained in them in an amount of 10-15%.

Stearic acid is almost never found in plants, but is found in significant amounts (25% or more) in some solid animal fats (sheep and bull fat) and tropical plant oils (coconut oil). There is a lot of lauric acid in bay leaf, myristic acid in nutmeg oil, arachidic and behenic acid in peanut and soybean oils. Polyunsaturated fatty acids - linolenic and linoleic - make up the main part of linseed, hemp, sunflower, cottonseed and some other vegetable oils. The fatty acids of olive oil are 75% oleic acid.

In the body of humans and animals, such important acids as linoleic and linolenic acids cannot be synthesized. Arachidonic - synthesized from linoleic. Therefore, they must be ingested with food. These three acids are called essential fatty acids. The complex of these acids is called vitamin F. With a long absence of them in food, animals experience stunting, dryness and flaking of the skin, and hair loss. Cases of insufficiency of essential fatty acids have also been described in humans. So, in infants receiving artificial nutrition with a low fat content, scaly dermatitis may develop, i.e. symptoms of avitaminosis appear.

Recently, much attention has been paid to omega-3 fatty acids. These acids have a strong biological effect - they reduce platelet adhesion, thereby preventing heart attacks, lowering blood pressure, reducing inflammation in the joints (arthritis), and are necessary for the normal development of the fetus in pregnant women. These fatty acids are found in fatty fish (mackerel, salmon, salmon, Norwegian herring). It is recommended to eat sea fish 2-3 times a week.

Nomenclature of fats

Neutral acylglycerols are the main constituents of natural fats and oils, most often mixed triacylglycerols. By origin, natural fats are divided into animal and vegetable. Depending on the fatty acid composition, fats and oils can be liquid or solid in consistency. Animal fats (lamb, beef, lard, milk fat) usually contain a significant amount of saturated fatty acids (palmitic, stearic, etc.), due to which they are solid at room temperature.

Fats, which include a lot of unsaturated acids (oleic, linoleic, linolenic, etc.), are liquid at ordinary temperatures and are called oils.

Fats are usually found in animal tissues, oils - in the fruits and seeds of plants. The content of oils (20-60%) is especially high in the seeds of sunflower, cotton, soybeans, and flax. The seeds of these crops are used in the food industry to produce edible oils.

According to the ability to dry in air, oils are divided into: drying (linseed, hemp), semi-drying (sunflower, corn), non-drying (olive, castor).

Physical Properties

Fats are lighter than water and insoluble in it. Highly soluble in organic solvents, such as gasoline, diethyl ether, chloroform, acetone, etc. The boiling point of fats cannot be determined, since when heated to 250 ° C, they are destroyed with the formation of aldehyde, acrolein (propenal), which strongly irritates the mucous membranes of the eyes, from glycerol during its dehydration.

For fats, there is a fairly clear relationship between the chemical structure and their consistency. Fats, in which the residues of saturated acids predominate -solid (beef, lamb and pork fat). If unsaturated acid residues predominate in fat, it hasliquid consistency. Liquid vegetable fats are called oils (sunflower, linseed, olive, etc. oils). The organisms of marine animals and fish contain liquid animal fats. into fat molecules greasy (semi-solid) consistency includes both the remains of saturated and unsaturated fatty acids (milk fat).

Chemical properties of fats

Triacylglycerols are capable of entering into all chemical reactions inherent in esters. The saponification reaction is of the greatest importance; it can occur both during enzymatic hydrolysis and under the action of acids and alkalis. Liquid vegetable oils are converted into solid fats by hydrogenation. This process is widely used to make margarine and cooking oil.

Fats with strong and prolonged shaking with water form emulsions - dispersed systems with a liquid dispersed phase (fat) and a liquid dispersion medium (water). However, these emulsions are unstable and quickly separate into two layers - fat and water. Fats float above water because their density is less than that of water (from 0.87 to 0.97).

Hydrolysis. Among the reactions of fats, hydrolysis is of particular importance, which can be carried out both with acids and bases (alkaline hydrolysis is called saponification):

Saponifiable lipids 2

Simple lipids 2

Fatty acids 3

Chemical properties of fats 6

ANALYTICAL CHARACTERISTICS OF FATS 11

Complex lipids 14

Phospholipids 14

Soaps and detergents 16

Hydrolysis of fats is gradual; for example, the hydrolysis of tristearin yields first distearin, then monostearin, and finally glycerol and stearic acid.

In practice, the hydrolysis of fats is carried out either by superheated steam, or by heating in the presence of sulfuric acid or alkalis. Excellent catalysts for the hydrolysis of fats are sulfonic acids obtained by sulfonation of a mixture of unsaturated fatty acids with aromatic hydrocarbons ( Petrov's contact). Castor seeds contain a special enzyme - lipase accelerating the hydrolysis of fats. Lipase is widely used in technology for the catalytic hydrolysis of fats.

Chemical properties

The chemical properties of fats are determined by the ester structure of triglyceride molecules and the structure and properties of hydrocarbon radicals of fatty acids, the residues of which are part of the fat.

Like esters fats enter into, for example, the following reactions:

– Hydrolysis in the presence of acids ( acid hydrolysis)

Hydrolysis of fats can also proceed biochemically under the action of the digestive tract enzyme lipase.

Hydrolysis of fats can proceed slowly during long-term storage of fats in an open package or heat treatment of fats in the presence of water vapor from the air. A characteristic of the accumulation of free acids in fat, which give the fat bitterness and even toxicity, is "acid number": the number of mg of KOH used for titration of acids in 1 g of fat.

– Saponification:

Most interesting and useful reactions of hydrocarbon radicals are double bond reactions:

– Hydrogenation of fats

Vegetable oils(sunflower, cottonseed, soybean) in the presence of catalysts (for example, sponge nickel) at 175-190 o C and a pressure of 1.5-3 atm are hydrogenated at double C \u003d C bonds of hydrocarbon radicals of acids and turn into solid fat. When so-called fragrances are added to it to give the appropriate smell and eggs, milk, vitamins to improve nutritional qualities, they get margarine. Salomas is also used in soap making, pharmacy (bases for ointments), cosmetics, for the manufacture of technical lubricants, etc.

– Addition of bromine

The degree of unsaturation of fat (an important technological characteristic) is controlled by "iodine number": number of mg of iodine used to titrate 100 g of fat as a percentage (analysis with sodium bisulfite).

– Oxidation

Oxidation with potassium permanganate in an aqueous solution leads to the formation of saturated dihydroxy acids (Wagner reaction)

rancidity

During storage, vegetable oils, animal fats, as well as fat-containing products (flour, cereals, confectionery, meat products) under the influence of air oxygen, light, enzymes, moisture acquire an unpleasant taste and smell. In other words, fat goes rancid.

Rancidity of fats and fat-containing products is the result of complex chemical and biochemical processes occurring in the lipid complex.

Depending on the nature of the main process occurring in this case, there are hydrolytic and oxidative rancidity. Each of these can be divided into autocatalytic (non-enzymatic) and enzymatic (biochemical) rancidity.

HYDROLYTIC RANCIENCY

At hydrolytic Rancidity is the hydrolysis of fat with the formation of glycerol and free fatty acids.

Non-enzymatic hydrolysis proceeds with the participation of water dissolved in fat, and the rate of fat hydrolysis at ordinary temperatures is low. Enzymatic hydrolysis occurs with the participation of the enzyme lipase on the surface of contact between fat and water and increases during emulsification.

As a result of hydrolytic rancidity, acidity increases, an unpleasant taste and smell appear. This is especially pronounced in the hydrolysis of fats (milk, coconut and palm), containing low and medium molecular weight acids, such as butyric, valeric, caproic. High molecular weight acids are tasteless and odorless, and an increase in their content does not lead to a change in the taste of oils.

OXIDATIVE RANCIENCY

The most common type of spoilage of fats during storage is oxidative rancidity. First of all, unsaturated fatty acids are oxidized, and not bound in triacylglycerols. The oxidation process can occur in non-enzymatic and enzymatic ways.

As a result non-enzymatic oxidation Oxygen attaches to unsaturated fatty acids at the double bond to form cyclic peroxide, which decomposes to form aldehydes, which give the fat an unpleasant odor and taste:

Also, non-enzymatic oxidative rancidity is based on chain radical processes involving oxygen and unsaturated fatty acids.

Under the action of peroxides and hydroperoxides (primary oxidation products), fatty acids are further decomposed and secondary oxidation products (carbonyl-containing) are formed: aldehydes, ketones and other substances that are unpleasant in taste and smell, as a result of which the fat becomes rancid. The more double bonds in a fatty acid, the higher the rate of its oxidation.

At enzymatic oxidation this process is catalyzed by the enzyme lipoxygenase to form hydroperoxides. The action of lipoxygenase is associated with the action of lipase, which pre-hydrolyzes fat.

ANALYTICAL CHARACTERISTICS OF FATS

In addition to the melting and solidification temperatures, the following values ​​are used to characterize fats: acid number, peroxide number, saponification number, iodine number.

Natural fats are neutral. However, during processing or storage due to hydrolysis or oxidation processes, free acids are formed, the amount of which is not constant.

Under the action of the enzymes lipase and lipoxygenase, the quality of fats and oils changes, which is characterized by the following indicators or numbers:

Acid number (Kh) is the number of milligrams of potassium hydroxide required to neutralize free fatty acids in 1 g of fat.

During storage of the oil, hydrolysis of triacylglycerols is observed, which leads to the accumulation of free fatty acids, i.e. to an increase in acidity. Increasing K.ch. indicates a decline in quality. The acid number is a standardized indicator of oil and fat.

Iodine number (Y.h.) - this is the number of grams of iodine added at the place of double bonds to 100 g of fat:

The iodine number allows you to judge the degree of unsaturation of the oil (fat), its tendency to dry out, rancidity and other changes that occur during storage. The more unsaturated fatty acids contained in the fat, the higher the iodine number. A decrease in the iodine number during storage of the oil is an indicator of its deterioration. To determine the iodine number, solutions of iodine chloride IC1, iodine bromide IBr or iodine in a sublimate solution are used, which are more reactive than iodine itself. The iodine number is a measure of the unsaturation of fatty acids. It is important for assessing the quality of drying oils.

Peroxide number (p.h.) shows the amount of peroxides in fat, expressed as a percentage of iodine isolated from potassium iodide by peroxides formed in 1 g of fat.

There are no peroxides in fresh fat, but when exposed to air, they appear relatively quickly. During storage, the peroxide value increases.

Saponification number (N.O. ) is equal to the number of milligrams of potassium hydroxide consumed during the saponification of 1 g of fat by boiling the latter with an excess of potassium hydroxide in an alcohol solution. The saponification number of pure triolein is 192. A high saponification number indicates the presence of acids with "smaller molecules". Low saponification numbers indicate the presence of higher molecular weight acids or unsaponifiables.

Oil polymerization. The reactions of autoxidation and polymerization of oils are very important. On this basis, vegetable oils are divided into three categories: drying, semi-drying and non-drying.

Drying oils in a thin layer they have the ability to form elastic, shiny, flexible and durable films in air, insoluble in organic solvents, resistant to external influences. The use of these oils for the preparation of varnishes and paints is based on this property. The most commonly used drying oils are shown in Table. 34.

Table 34. Characteristics of drying oils

The main characteristic feature of drying oils is the high content of unsaturated acids. To assess the quality of drying oils, the iodine number is used (it must be at least 140).

The drying process of oils is oxidative polymerization. All unsaturated fatty acid esters and their glycerides oxidize in air. Apparently, the oxidation process is a chain reaction leading to an unstable hydroperoxide, which decomposes to form hydroxy and keto acids.

Drying oils containing glycerides of unsaturated acids with two or three double bonds are used to prepare drying oils. To obtain drying oil, linseed oil is heated to 250-300 ° C in the presence of catalysts.

Semi drying oils (sunflower, cottonseed) differ from drying ones in a lower content of unsaturated acids (iodine number 127-136).

Non-drying oils (olive, almond) have an iodine value below 90 (for example, for olive oil 75-88).

Waxes

These are esters of higher fatty acids and higher monohydric alcohols of fatty (rarely aromatic) series.

Waxes are solid compounds with pronounced hydrophobic properties. Natural waxes also contain some free fatty acids and macromolecular alcohols. The composition of waxes includes both the usual ones contained in fats - palmitic, stearic, oleic, etc., and fatty acids characteristic of waxes, which have much larger molecular weights - carnoubic C 24 H 48 O 2, cerotinic C 27 H 54 O 2, montanic C 29 H 58 O 2, etc.

Among the macromolecular alcohols that make up waxes, one can note cetyl - CH 3 - (CH 2) 14 -CH 2 OH, ceryl - CH 3 - (CH 2) 24 -CH 2 OH, myricyl CH 3 - (CH 2) 28 -CH 2 OH.

Waxes are found in both animal and plant organisms and perform mainly a protective function.

In plants, they cover leaves, stems and fruits with a thin layer, thereby protecting them from wetting with water, drying out, mechanical damage and damage by microorganisms. Violation of this plaque leads to rapid deterioration of the fruit during storage.

For example, a significant amount of wax is released on the surface of the leaves of a palm tree growing in South America. This wax, called carnouba wax, is basically a cerotinic myricyl ester:

,

has a yellow or greenish color, is very hard, melts at a temperature of 83-90 0 C, goes to the manufacture of candles.

Among animal waxes, beeswax is the most important, honey is stored under its cover and bee larvae develop. In beeswax, palmitic-myricyl ether predominates:

as well as a high content of higher fatty acids and various hydrocarbons, beeswax melts at a temperature of 62-70 0 C.

Other representatives of animal wax are lanolin and spermaceti. Lanolin protects hair and skin from drying out, a lot of it is found in sheep's wool.

Spermaceti - a wax extracted from the spermaceti oil of the sperm whale cranial cavities, consists mainly (90%) of palmitic-cetyl ether:

solid, its melting point is 41-49 0 C.

Various waxes are widely used for the manufacture of candles, lipsticks, soaps, various plasters.

Classification and characterization of fatty acids

The fatty acids that make up fats are monobasic , contain even number of carbon atoms , have normal structure hydrocarbon chain.

Depending on the number of hydrocarbon groups in the hydrocarbon chain, i.e. radical length, fatty acids are subdivided into low molecular weight (with radical length up to 9 groups) and macromolecular ; and depending on the nature of the bond of carbon atoms in the hydrocarbon chain - on marginal (saturated) , which are connected by one single bond, and unsaturated (unsaturated), having double bonds.

Low molecular weight fatty acids are only marginal: butyric, caproic, caprylic, capric; they are soluble in water, volatile with water vapor, have specific (unpleasant) odors, and are liquid at room temperature. High molecular weight fatty acids are limiting: lauric, myristic, palmitic, stearic, arachidic and others, as well as unsaturated: oleic, linoleic, linolenic, etc. High molecular weight fatty acids are insoluble in water, have no odor, solid at room temperature, as they lengthen radical, their properties gradually change. Unsaturated fatty acids are part of fats of vegetable and animal origin.

About 70 different fatty acids are known in nature, but only 5 are most commonly found in fats:

palmitic- CH 3 (CH 2) 14 COOH;

stearic- CH 3 (CH 2) 16 COOH;

oleic CH 3 (CH 2) 7 - CH \u003d CH - (CH 2) 7 COOH;

linoleic CH 3 (CH 2) 4 - CH \u003d CH - CH 2 - CH \u003d CH - (CH 2) 7 COOH;

linolenic- CH 3 - CH 2 - CH \u003d CH - CH 2 - CH \u003d CH - CH 2 - CH \u003d CH - (CH 2) 7 COOH;

from the above formulas it can be seen that of the five acids, two are saturated and three are unsaturated. All fatty acids that make up fats contain an even number of carbon atoms - from 14 to 22, but more often 16 or 18.

Limit fatty acids are less reactive than unsaturated ones. So, the fats of marine animals and fish contain fatty acids, in the molecules of which there are 4 and 5 double bonds, and this causes the instability of such fats during storage. Thus, the rust that appears during storage of herring is due to the oxidation of fats with a large number of double bonds.

The higher the molecular weight of saturated fatty acids, the higher their melting point. (Table 16). Fats rich in saturated macromolecular acids have a solid texture, high melting point and are less absorbed by the body. Due to the presence of double bonds in the molecule, unsaturated fatty acids have a lower melting point compared to saturated fatty acids that have the same number of carbon atoms in the molecule (Table 17).