"Dairy products. Quality research. role in human life. Design and research work “Milk and health. study of the properties of milk Determining the quality of milk at home project

10.11.2020

RESEARCH WORK ON HEALTHY NUTRITION

"Determining the quality of milk at home"

INTRODUCTION

Milk is one of the most important human food products. In its composition, the most necessary substances for human health were found. Fats and carbohydrates are sources of energy. Proteins contain all the necessary amino acids, including those that are not synthesized by the human body.

Minerals contained in milk contribute to the formation and absorption of vitamins, are part of human tissues. Milk contains all known vitamins.

The exclusion of milk from the diet can lead to a decrease in the necessary substances in the body.

Currently on store shelves appeared a large number of dairy products.

In Novosibirsk, it is not often possible to find natural fresh milk for sale from private producers or peasant farms. Mostly Novosibirsk people use milk from the store in their diet. This project aims to find out the quality of milk from the store and show how you can investigate the quality of milk

object our research becomesmilk , which our parents, and not rarely, you and I buy at a regular grocery store.

Subject research is the process of determining quality milk.

Objective of the project:

Learn to identify a quality product (milk) at home.

Transfer of acquired knowledge, skills and abilities to the public by filming and showing a video about “experimental testing of milk quality at home”.

Show the advantages and disadvantages of a product of a certain sample, to determine the possibility of its use or unacceptability in nutrition.

Tasks project:

Conduct a theoretical analysis of the literature on this issue;
Conduct the necessary experiments to determine a quality product;
Draw conclusions and rationale for the work;
Make a video on the experimental testing of milk at home;
Showing a video at the school NPC (scientific and practical conference);
Placement of the video on the Internet and social networks.

Methods project:

Studying information on the topic;

Experiment;

Observation;

Comparison of facts;

Analysis of results;

Processing of results;

Formulation of conclusions;

Shooting video;

Processing and editing of video files;

Video broadcast.

Project product: determination of the quality of store-bought milk, a video about the methods of experimental study of the quality of milk.

Practical significance project is that I conducted experiments to determine the quality of milk and shot a video for parents and students with recommendations for determining the quality of milk at home to determine the possibility of its use or unacceptability in nutrition.

THEORETICAL JUSTIFICATION OF THE PROJECT

Determining the quality of products by smell, taste and color cannot provide complete and reliable information, and sometimes it can be dangerous to health. You can check the quality of milk at home without resorting to the “testing” method. To do this, you do not need to conduct complex laboratory studies, it is enough that you always have at hand.In addition to diluting milk with water, starch, gypsum, chalk, soap, soda, potash, borax, lime, and even chemical products such as boric and salicylic acids are often mixed with it. Some of these substances are mixed in to make the skimmed milk look whole, not skimmed; others - to protect against rapid sourness, in general spoilage, to which milk is subjected to the sooner, the more foreign organic impurities it contains.
In fact, the admixture of these impurities is not able to protect milk from sourness. Moreover, even the most “innocent” of these impurities, for example, bicarbonate of soda, is in fact very harmful, and precisely because, as was found by direct experiments, an admixture of bicarbonate of soda, among other things, serves the best condition for enhanced reproduction in milk of various pathogenic microbes - cholera bacilli, tuberculosis and others. ("Encyclopedia of Technologies and Methods" Patlakh V. V. 1993-2007)

There are several methods for determining the quality of milk. Some of them require special laboratory conditions with necessary equipment and reagents. But some can be done at home. Milk should be checked immediately after opening the package.

Compound

The first thing to check when buying milk is the composition of the product. Currently, in Russia there is a law according to which if powdered milk is added to milk, then the label must say that this is a milk drink and, accordingly, this must also be noted in the composition.

When buying a bag labeled "milk", we expect that we are paying for milk, and not for a milk drink that is made from dry mixes. However, sometimes we are deceived with impunity.

The situation with milk in our country, to put it mildly, is confusing. Despite the existence of GOST, technical regulations and other documents, a method has not yet been developed that would allow determining whether there is powdered milk in drinking milk.

Abroad, if the milk is reconstituted from dry, they write so on the packaging - “reconstituted milk,” explainsLarisa Abdullaeva, executive secretary of the Dairy Union of Russia.- We have come up with the term "milk drink", but no one indicates it on the packaging

(http://www.aif.ru/gazeta/number/379)

If on the milk you bought in the COMPOSITION section it is written that it is:whole milk means good quality milk.

If it is written: reconstituted or normalized, therefore, the milk is made from milk powder, or with its addition.

The amount of protein in milk decreases in winter and cannot exceed 3%. And the packages often indicate much larger numbers. There is no live milk with such indicators in Russia: animal selection has not been carried out for a long time, there are complaints about the quality of feed. If natural milk really contains high protein, the manufacturer will direct such valuable raw materials to cheese or cottage cheese, and will not make ultra-pasteurized milk from it. (from an interviewElena Petrova, OZPP expert).

If the packaging indicates a high protein content, then the milk has most likely been reconstituted.

Determination of impurities

It is quite easy to determine the "purity" of the product, for this you need to strain a certain amount of milk through a dense white cloth, or a cotton pad.

If you notice villi, any grains of a substance, it means that the milk production was not followed sanitary norms, and such milk can be dangerous.

"Dirty glass"

During this check, we check the density of milk (fat content), therefore, after stirring the milk in a glass, carefully look at its walls, the “dirtier” your glass turns out to be, the better quality milk. It should be noted that the layer of milk on the walls must be uniform.

Litmus.

Sometimes manufacturers, whose product stays on store shelves for a long time, add soda to milk, which slows down the souring process. You can determine the content of soda in milk using litmus papers.

Most likely, not every home has a paper acid-base indicator, but if you set out to check food at home before eating, it is not difficult to get one at a pharmacy.

With the help of litmus papers, you can check the acidic environment of products, in our case, milk.

Pour milk samples into different containers;

It is necessary to moisten one strip of indicator paper in the milk sample;

We wait 1-2 minutes and carefully examine the strip;

We draw conclusions on the color of litmus paper:

With complex adulteration of milk, the most important thing to beware of is chemical impurities, for the detection of which this test can be of no small benefit. Unskimmed, whole milk has a very characteristic double reaction, which is that it is at the same time somewhat alkaline and slightly sour; as a result, a blue litmus paper soaked in whole milk turns slightly red, and a red one turns slightly blue.
On the contrary, if there is an excess of alkali in milk, for example, from the admixture of soda to it, then the red litmus paper turns very blue, while the blue one completely retains its color.
Similarly, if an acid, such as boric or salicylic acid, is mixed into milk, then blue litmus paper, moistened with such milk, turns bright red; red does not change its color at all.

IODINE

The presence of starch, which is added to milk to make it thicker, can be easily and quickly determined using ordinary iodine from a home medicine cabinet.

AT a small amount of milk should drip a few drops of an alcohol solution of iodine.

Staining in blue, will show the presence of starch in the product;

A yellow-orange color indicates the absence of starch in the milk.

Alcohol

With the help of alcohol, you can accurately determine whether milk is diluted with water. For this you need:

- to one part of milk, add two parts of alcohol;

- the resulting mixture is actively shaken for 1 minute;

- after shaking, it is necessary to pour the mixture of milk and alcohol into a plate or saucer, carefully observing the state of the mixture and fixing the time after which white flakes appear in it;

- rapid, within 5-6 seconds, the formation of casein flakes released from whey will indicate the high quality of milk;

- if the flakes appear late, then the milk is diluted with water.

By the time of formation of casein flakes, one can judge the degree of dilution of milk with water. If it took about a minute for the formation of flakes, then 20% of the volume was replaced by water, an interval of 25-30 minutes will indicate a 40% water content in milk, and if casein flakes began to appear onlyafter 40 minutes, such milk is diluted with water by half.

7. Warm water.

By pouring a small amount of milk into a glass of warm water in a thin stream, it is possible to determine with a high degree of probability whether it has been diluted with water.

High-quality milk in the form of a white clot will collect in the upper part of the glass, glass, diluted milk will behave differently - it will almost completely dissolve in water, coloring it in an off-white color.

If milk is poured in quickly, good quality milk will first sink to the bottom of the glass, and then slowly dissolve when diluted with water immediately turns the water off-white.

8. Filter paper

Another way to determine the degree of dilution of milk with water . If you do not have filter paper at home, then you can use a paper napkin or toilet paper. The main requirement is that they must be of a sufficiently high quality.

Having dipped a thin stick, a toothpick or a match into the milk, you need to put a small drop of milk on the surface of the filter paper. It is very important that it be as small as possible and at the same time be as convex as possible, resembling a hemisphere. For the reliability of the result of such drops, it is better to put a few.

Since the filter paper has a finely porous surface structure, it will begin to absorb the water contained in the milk. Therefore, on the surface of the paper, a wet ring will appear around the drop, the width of the ring will be the greater, the greater the amount of water in the milk.

A drop of undiluted milk will create around itself a wet ring no more than 1 mm thick, which, when room temperature dry in about 2 hours.

The water spot around a drop of milk diluted with water by 10% will be noticeably wider and will dry faster - in about an hour. In half an hour, the ring around a drop of milk diluted by 30% will dry, and it will take only 10-15 minutes to dry the ring left by a drop of milk diluted in half.

Checking for antibiotics

The milk that we buy in the store undergoes a special treatment. It is purified from various impurities. In order to destroy microorganisms, pasteurization of milk, ultra-pasteurization and sterilization are carried out.

Pasteurization - heating milk from 63 degrees to a temperature close to the boiling point. Pasteurization destroys vegetative forms of microbes, and sterilization destroys spores at the same time. When boiling, the entire microflora of milk is destroyed, with the exception of spores that are resistant to the boiling point.

Sterilization milk aims to destroy all microorganisms. In this case, the milk is first heated to 75 degrees, then in a split second it is heated under high pressure. In another method, the milk is sprayed and, at the time of spraying, heated to the temperature of superheated steam. Bacteria are instantly killed. The milk is then cooled and packaged.

Sterilized milk obtained in one way or another does not change its taste. In hermetically sealed containers, sterilized milk can be stored for a long time at room temperature.

UHT It is used to destroy microflora and at the same time preserve the natural properties of milk. Ultra-pasteurization is carried out at a temperature of 105 to 150 degrees with exposure from a few seconds to fractions of a second. Then the milk is quickly cooled in 4-6 seconds.

Unfortunately, at home it is impossible to check whether the purchased product is natural or made from milk powder. But checking milk for the presence of antibiotics and various substances that slow down the growth of bacteria is very simple. Natural and without additives, milk left at room temperature should turn sour in a day.Pasteurized milk turns sour for 2-3 days, ultra-pasteurized and sterilized milk may not turn sour for quite a long time.

PRACTICAL PART

The practical part includes a description of the work on the study of milk quality, in the framework of the above studies.

Municipal budgetary educational institution

"Znamenskaya middle comprehensive school»

Orlovsky district, Oryol region

Research work on the topic:

"Studying the composition of milk at home"

Completed:

3rd grade student

Kolesnikov Dmitry

Objective of the project :

▪ To study the meaning and composition of milk.

Project objectives:

▪To study the literature on milk, to determine the importance of milk for a growing organism;

▪ Examine the composition of milk.

Hypothesis:

"Milk is an amazing food prepared by nature itself." (Academician I.P. Pavlov).

Introduction

Milk is of great importance in the nutrition of children of all ages and especially the first year of life. Pet milk is an excellent food for maintaining life, ensuring the growth and development of the child. It is indispensable for the nutrition of children, as it contains high-value proteins, fats, carbohydrates, minerals and vitamins. Now it is easiest to find out what milk is, why milk contains strength and health. in kindergartens and primary school a healthy diet includes milk, dairy and sour-milk products.

Theoretical part

Milk composition

Nature has made milk rich in biologically active substances. Substances useful for a living organism will be needed for the development and maintenance of vital functions.

High the nutritional value milk is that it contains about 200 vital substances for humans: up to 20 amino acids, about 60 fatty acids. A whole set of sugars, a large amount of minerals, all kinds of vitamins, enzymes, hormones, microelements. The proteins contained in milk are of particular importance for baby food, as they contribute to the normal development of the child, being a building material for building the cells of his body. The fats necessary for children, which serve as a source of heat in the body, can be obtained using the same milk. The fat of dairy products is the most useful, because it is very easy to digest and rich in vitamins A, B, C, D, E. The digestibility of milk fat is the highest compared to other fats. It is well absorbed by the child's body and milk sugar is a necessary component of children's food. Of the minerals found in milk, calcium and phosphorus should be distinguished, which are of great importance for the development of the child's body. A very important role is played by the iron salts contained in milk, which are part of erythrocytes. With their deficiency, the child develops anemia.

Milk, which animals a person consumes. The most common is cow's milk. However, milk of different animals is used in nutrition: cows and mares, goats, camels, deer and sheep, buffaloes and donkeys, female yaks and zebu. And once they even valued the milk of pigs, which is now practically out of use.

Cow's milk. AT cow's milk has all the substances necessary for the body - proteins, fats, carbohydrates, mineral salts, vitamins, enzymes, trace elements.

Camel milk - shubat. D For Arabs, shubat is both food and medicine. It is used to treat many diseases: asthma, tuberculosis, inflammation of the liver, diabetes, psoriasis. It has a specific taste, sharp and salty, which is called "an amateur". If we compare the usual cow's milk with camel's, it turns out that the latter contains three times more vitamins C and D, but less milk sugar - lactose. Camel milk contains significantly more protein, fat, minerals and vitamins than kefir.

Mare's milk - koumiss. Kumis is recognized as a useful general tonic. Its taste is pleasant, refreshing, sour-sweet. Kumis has a positive effect on metabolism, it is recommended for diseases of the liver, lungs and stomach, scurvy, gastritis. Compared to cow's milk, koumiss contains many more vitamins and minerals.

Goat milk. Goat milk is more popular in the world than cow milk. In it, as in mare's milk, there are more vitamins and microelements, in comparison with cow's milk, familiar to Russian consumers.

Donkey milk. Numerous studies have found that certain proteins found in donkey milk stimulate collagen synthesis. And this substance, as you know, is the structural basis of the skin. So donkey milk is indeed a kind of analogue of the “elixir of youth”. In addition, donkey milk contains antioxidants.

Buffalo milk. Compared to cow's milk, buffalo milk has more fat, protein, calcium, vitamins A, C and group B. In addition, it contains practically no casein protein, which causes allergies in many people.

Sheep milk. Sheep milk is one and a half times more nutritious than cow milk: it contains more vitamins A, B and B 2 . They make curdled milk, kefir, butter, cheeses from it. But fresh sheep's milk is rarely drunk - it has a rather specific smell.

Deer milk. Reindeer milk is drunk by the peoples of the North. This is the most high-calorie milk: it has three times more protein and 5 times more fat than cow's milk. Not every stomach can digest reindeer milk, so whole milk is usually diluted with water.

Interesting Milk Facts:

▪ Cow's milk proteins can bind toxins in the body. That is why people still, workers in hazardous industries receive free milk.

▪ It turns out that when milk is stored in a glass container, it loses a lot of vitamins very quickly, which are destroyed in the light. Therefore, milk must be stored in a dark place.

▪ Russians were the first to learn how to make sour cream and cottage cheese, Ukrainians - varenets, Kazakhs - airan, Karachay highlanders - kefir, Georgians - matsoni.

▪ Not everyone knows that milk perfectly quenches thirst. In the heat, the body loses a lot of moisture in the form of sweat, and mineral salts are removed with it. Milk, which contains these salts, helps retain moisture and thus reduces thirst. The centuries-old experience of the inhabitants of Central Asia shows that sour skimmed milk or whole milk diluted with water is good for quenching thirst.

Practical part.

For the study, I took samples of milk "Prostakvashino" 4.0%, "Lebedyan" 3.2%, "Avida" 2.5%. Test tubes and a tripod were brought to me by my mother from work. She works at a factory that produces dairy products.

Experience number 1. Determination of fat in milk

Fat does not mix with water. In milk, fat does not immediately separate from the water, it can be seen only if the milk has been standing for a long time. Then the fat will float to the surface. It's cream. Milk fat is found in milk in the form of globules that form an oil-in-water emulsion with water. Fat globules are protected by strong elastic shells of protein, and therefore do not stick together. Place a drop of each milk sample on filter paper. Drops should be the same. When they dry, I measured the diameter of each spot with a ruler. The larger it is, the higher the fat content in milk. Commercially available milk has almost the same fat content.

Experience number 2. Detection of protein in milk

I poured a few milliliters of each sample of milk into test tubes and carefully added an equal volume of a weak solution of copper sulphate (pale blue) and a little alkali solution along the walls. A purple color appeared. This indicates the presence of protein in the product under study. Milk contains several types of protein. The main protein is casein. It is from casein that cottage cheese is formed. When milk is fresh, all proteins are dissolved. But if the milk is sour, you notice that it has become thicker - it has turned into curdled milk. If it is heated, then a precipitate of protein precipitates. This is how curd is made. But if you do not want to wait until the milk turns sour, you can add food acid to it - acetic or citric acid and get a casein precipitate.

Experience number 3. Determination of the presence of casein in milk

I poured milk from all samples into cups and added a few drops of

vinegar essence, stirred, and saw the formation of white flakes. It's casein.

Experience No. 4 Getting whey

When casein precipitates, other proteins and lactose remain in the liquid part - whey. To obtain serum, the precipitate must be filtered. To do this, I took a small glass, made a funnel out of gauze and poured milk into the funnel to form curd. Cottage cheese (casein) remained on gauze, and whey was glassed into a glass, so I got whey.

Experience number 5. Serum protein detection

To find out if there is protein in the serum, I added a solution of copper sulfate and alkali to the samples and mixed it. The color of the serum turned purple. This shows that there is still a lot of protein left in the whey. Therefore, whey is also a useful and nutritious product.

Experience number 6. Detection of carbohydrates in milk

I poured a little whey into a cup and began to heat it over the fire. After the liquid evaporates, the whey chars and a sweet smell appears. This proves that there are carbohydrates in milk.

Experience No. 7 milk ink

The most mysterious for me experience about cryptography. On a clean sheet of paper he wrote the text with milk. When the milk dried up, I heated the paper with an iron (I ironed the paper), and found the written text, which appeared when heated.

comparison table

Sample #1

Milk "Prostokvashino" 4.0%

Sample #2

Milk "Lebedyan" 3.2%

Sample #3

Avida milk 2.5%

Milk color

white

The smell of milk

milky

The taste of milk

milky

Fat spot diameter

2 cm

1.5 cm

1.0 cm

Color when reacting to protein

light purple

Did you manage to get a precipitate of casein

Yes

Serum color

cloudy white

Did you manage to detect carbohydrates

Yes

Conclusion: My research confirmed my hypothesis. Milk is a very useful and valuable food product, especially for a growing organism. Milk contains fats, proteins and carbohydrates - the most important sources of energy and construction material for a person. Milk helps to have strong nerves and good immunity. Milk is the best food before bed. Therefore, it is not in vain that they say: “Drink, children, milk - you will be healthy!

Goryansky I.A. one

1 Municipal educational institution "Gymnasium No. 24", Kaluga, 5A

Koshevich O.A. 1 Domorod a.v. 1

1 Municipal educational institution "Gymnasium No. 24", Kaluga

The text of the work is placed without images and formulas.
Full version work is available in the "Files of work" tab in PDF format

Content

I. Introduction 2

II. Main part 3

1. Theoretical part 3

1.1. Milk composition 3

1.2. Benefits of milk 4

1.3. Human use of milk 4

2. Experimental part 5

2.1. Stage 1. Determining the quality of milk. 5

2.2 Stage II. Determination of the composition of milk. nine

2. 3. Stage III. Determination of the presence of dangerous microorganisms in the composition of milk. thirteen

III. Conclusion 14

IV. Conclusions: 15

V. References 15

I Introduction

I became interested in studying the quality and composition of milk after my parents decided to buy milk in the village “from their own cow” instead of “store-bought” milk from a well-known manufacturer.

For some time I did not agree to drink "village" milk "from my cow", since "store" milk is sold in a package that indicates the manufacturer, shelf life, fat content, composition, etc.

And how to find out the quality and composition of "village" milk. Although, however, as I found out later, large producers and sellers of milk are not always conscientious: they produce, transport and store milk correctly.

Then the idea came to my mind - to find ways to check the quality and composition of milk. But since we eat milk every day, the laboratory study did not suit me. I started researching if there were "at home" ways to test milk in my own kitchen.

Thus, the ordinary kitchen in my apartment turned into a scientific laboratory. I managed to feel like a real chemist at home.

So I decided to investigate the composition and properties of milk.

Relevance:

The relevance of this work is that milk is a very useful product that we use daily.

But at the same time, some caution should be exercised when using milk: milk is a good breeding ground for bacteria, some people, for health reasons, should use milk with caution.

In order for the use of milk to be useful and safe for humans, it is necessary to explore ways to determine the quality of this product not only in the laboratory, but also at home.

Since the health of people always has great importance and value for society as a whole, I consider my research work relevant.

Objective: study of methods for studying the quality and composition of milk of various origins at home.

Work tasks:

1. Study the material on the research topic.

2. Prepare and conduct an experiment to study the quality and composition of milk of various origins.

3. Monitor and record results.

4. Process the results and draw conclusions: identify the features of the quality and composition of milk of various origins.

Object of study: cow's milk.

Subject of study: ways to study the quality and composition of cow's milk of various origins at home.

Hypothesis: I believe that the methods proposed in the work will help to obtain data on the quality and composition of milk at home.

Practical significance

In this paper, we explore and propose practical ways to determine the quality and composition of milk, which can be carried out at home.

We humans need to be aware of the quality and composition of the foods we eat every day, including milk. This will allow us to protect our health from low-quality milk, to use and store this food product correctly, since human health depends on it.

II. Main part 1. Theoretical part 1.1. Milk composition

The milk of any mammal is its mother's milk. It contains proteins, fats, a special carbohydrate peculiar only to milk - lactose (milk sugar), minerals, vitamins, hormones. The main substances of food are proteins, fats and carbohydrates. Fats provide the most energy. Protein is the main building material, a participant in metabolic processes in the body. The carbohydrate in milk is called lactose. But unlike glucose or sucrose (food sugar), lactose has almost no sweet taste. Carbohydrates are the source of vital energy in our body.

1.2. The benefits of milk

Remember that mammals feed their young with milk. We conclude that milk is a special food for children, which means that it is very useful and easily absorbed even by a delicate children's body. Nature, having provided parents with a factory-kitchen, or, more precisely, dairies, "insured" the younger generation from the vagaries of the weather. Neither cold, nor drought, nor heavy rains, even temporary starvation, are not terrible for young mammals. In some mammals, females do not eat anything at all while nursing their children. But as long as there is at least a drop of fat in the mother's body, the milk factory will work normally - their cubs will receive good nutrition.

1.3. human use of milk

But as the history of the development of human society shows, for a person milk turned out to be necessary product in all periods of his life, as food, a means to quench thirst in places where there is not enough water, as a medicine, especially for the elderly and sick people. Man decided to use the milk of other mammals to satisfy his growing need for this product. But in animals, the composition of milk is different.

People eat mainly cow's milk - this is the mother's milk of cows. It is produced in large quantities and is the most sought after type of animal milk.

But not always we can buy a quality product. Sometimes, having bought a beautiful package of milk at first glance, at home we are confused by the smell, color or taste of the purchased product. Milk sometimes turns out to be unnaturally thick or too watery. Sometimes “village” milk “from one’s own cow” also causes doubts about the quality and safety.

How to protect yourself and your health from unscrupulous milk producers and sellers? Of course, learn to determine its quality and composition at home.

2. Experimental part

All experiments were carried out at home. For experiments, I took milk “from my cow” (the village of Kolyupanovo, Kaluga region) and ultra-pasteurized milk 1.5% of the Vkusnoteevo brand. In order to determine the types of experiments with milk, I have identified the main food substances in milk and their properties:

protein - can "curl" from exposure to temperature or acids.

fats are lighter than water, leave “greasy” spots on fabric and paper, carbohydrates turn brown when heated and exude the smell of burnt sugar.

For falsification in order to "improve" the quality and composition of milk, add:

starch (for thickening) - turns blue when reacting with iodine,

soda or lime (so that milk does not sour for a long time) - “boils” when reacting with acetic acid,

water (to increase volume) - the volume of the product increases, but the concentration of other substances decreases.

So, let's try to experiment.

2.1. Stage 1. Determining the quality of milk.

Experiments "Characterization of the quality of milk based on perception by the senses"

Purpose: to determine whether there are defects in taste and smell in milk samples that indicate a violation of the rules for milking, storage, transportation and processing of milk.

At home, I conducted an experiment and wrote down my observations.

The quality of milk can be determined by its appearance.

Equipment: glass beaker 100-250 ml.

Working process:

1. Pour into a glass of milk until the middle of the volume. 2. Carefully examine the milk for impurities, impurities and note whether it is homogeneous. 3. Let the milk stand for 3-5 minutes and note the presence or absence of sediment.

Quality milk determines its color.

Equipment: a transparent glass beaker for 100-250 ml, a white sheet of paper.

Working process: 1. Pour 50-60 ml of milk into a glass. 2. Bring a white sheet of paper to the glass and compare the color.

Determining the consistency of milk

Equipment: jar with lid

Working process: 1. Pour into a jar of milk to the middle of the volume. 2. Close the jar with a lid and shake it slightly to wet the walls. 3. Let the milk drain and evaluate the result within 1-2 minutes.

Determining the smell of milk

Equipment: jar with lid

Working process: 1. Pour a little more than half of its volume into a jar of milk, close with a cork. 2. Open the test tube, immediately smell it. The smell is determined by repeated short inhalations, directing the air with the palm of your hand towards the nose. Do not inhale directly from the tube!

Determining the taste of milk

Equipment: glass beaker.

Reagents: drinking water.

Progress of work: 1. Pour 10-20 ml of milk into a glass. 2. Take a sip of milk in your mouth, trying to distribute it throughout the mouth, hold it for a while. Define taste.

After each sample of milk, rinse your mouth with water and take short breaks between individual determinations.

	Sample 1	Sample 2
Appearance

Consistency	Liquid, homogeneous	Liquid, homogeneous
	Weak, pleasant	Weak, pleasant
	Sweet-salty	Delicate, sweet-salty

Conclusion: milk of samples 1 and 2 is a product that meets the norm, since it has no defects in taste and smell, which indicates that there was no violation of the rules for milking, storage, transportation and processing and can be eaten.

Experiments "Determining the presence of impurities in milk"

Purpose: to determine whether there are impurities in milk samples that indicate the quality and composition of milk

Determination of starch in milk as a thickener

Equipment: glass, pipette, iodine.

Working process: 1. Pour into a glass of milk up to half its volume. 2. Draw a little iodine into the pipette. 3. Add to milk. 4. Let the milk stand.

Determination of water in milk to increase the volume of the product

Equipment: cup, pipette, ethyl alcohol.

Working process: 1. Pour into a glass of milk up to half its volume. 2. Add ethyl alcohol to milk. 3. Stir and let the milk stand for 5-7 seconds.

Determination of soda (lime) in milk as a neutralizer of lactic acid

Equipment: glass, acetic acid 9%.

Working process: 1. Pour into a glass of milk up to half its volume. 2. Add acetic acid to milk.

		No impurity	There is an admixture	Sample 1	Sample 2
1. Starch		Slightly yellow	Will turn blue	Slightly yellowed	Slightly yellowed
	Ethyl	Flakes form in 5-7 seconds	Flakes form in more than 7 seconds
(lime)	Acetic acid 9%	Not "boiled"	"Boiled"	Not "boiled"	Not "boiled"

1. There are no thickening impurities in samples 1 and 2.

2. Sample #2 (1.5% fat-free) contains very little water, Sample 1 is milk undiluted with water.

3. Soda (lime) was not detected in samples 1 and 2.

Milk samples 1 and 2 are safe for consumption and can be eaten. A slight admixture of water was found in sample 2.

Consumer rating:

sample number 1 - excellent quality,

sample No. 2 - the quality is satisfactory.

2.2. Stage II. Determination of the composition of milk.

Experience 1 "Determination of fat in milk"

Target: study the fat content of milk

Equipment: 2 napkins, pipette, ruler, milk jars.

Working process: 1. Pour the same volume of milk samples 1 and 2 into the jars.

2. Let the milk stand for a long time. 3. Fat will float to the surface. This will be the cream. 4. Measure the thickness of the cream layer

Result: a layer of cream of different thickness formed in the jars. The thickness of the cream layer is greater in sample 2 than sample 1,

Conclusion: it means that milk from “one’s own cow” is fatter than milk from Vkusnoteevo.

Method 2: Check the result.

Target: determine the fat content of milk.

Progress of work: 1. Apply a drop of each sample of milk to the filter paper (the drops are the same) 2. When the drops dry, measure the diameter of each spot with a ruler.

Result: There were greasy stains of different sizes on the napkins. The spot diameter of sample 1 is 19 mm and the spot diameter of sample 2 is 24 mm.

Conclusion: the conclusion of experiment 1 was confirmed. Milk from “your own cow” is fatter than Vkusnoteevo milk. Milk is a useful product, since fats provide the greatest amount of energy, and a person at any age needs it.

Experience 2 "Determination of proteins in milk"

Target: to investigate whether there are proteins in milk and compare which sample has more of it.

Equipment: milk cups, pipette

Reagents:

Working process: 1. Pour a few ml (milliliters) of milk into a glass. 2. Carefully add an equal volume of a weak solution of copper sulphate (pale blue) and a little washing soda solution along the walls 3. Mix.

Result: in sample 1 and 2, the solution turned purple. But in sample 2, the color is brighter.

Conclusion: this suggests that any cow's milk contains proteins. In sample 2 (milk from own cow), the color is brighter, which means the protein content is higher there.

Experience 3 "Determining the presence of casein - the main protein in milk"

Target: to investigate whether there is casein in milk and compare which sample has more of it.

Equipment: cups for milk, a tablespoon for milk, a pipette for acetic acid.

Reagents: acetic acid (9%).

Working process: 1. Pour 5 tablespoons of milk into a glass. 2. Add 1 tablespoon of acetic acid (9%) 3. Stir.

Result: samples 1 and 2 contain casein - you can see the formation of white flakes.

Conclusion: which suggests that any cow's milk contains casein, but milk from one's own cow has more casein.

Milk is a very useful product, as it contains protein, which is the most important building material and is involved in metabolic processes in humans of any age.

Experience 4 "Obtaining whey"

Target: receive milk whey and compare the taste, smell and color of the sera of samples 1 and 2.

Equipment: 2 small glasses, funnel, gauze, 2 saucepans, heater.

Working process: 1. Let the milk turn sour. 2. Heat until a precipitate forms. 3. Take a small glass. 4. Place a funnel in it. 5. Put a filter in it from several layers of gauze or a bandage 6. Pour milk with curd into the funnel - filter out the sediment

Result: in samples 1 and 2 curd (casein) and whey were formed. Cottage cheese (casein) remained on the filter, whey - in a glass.

Conclusion: the smell and taste in sample 1 and 2 is the same - sour, but the color is different. In sample 1, the color of the serum is light green, the consistency is liquid. In sample 2, the color is yellow, the consistency is thickish. In sample 2 there is more curd and less whey, while in sample 1 the opposite is true.

Experience 5 "Detection of proteins in serum"

Target: to investigate whether proteins remain in the serum after

Equipment: a weak solution of copper sulfate (pale blue), a little solution of washing soda

Working process: 1. Pour a few ml (milliliters) of serum into a test tube. 2. Carefully add an equal volume of a weak solution of copper sulphate (pale blue) and a little solution of washing soda along the walls 3. Mix.

Result: a purple color appeared, but in cup 1 the color is less intense than in cup 2.

Conclusion: in sample 1 and 2, the solution turned purple. Swatch 1 has a lighter color and Swatch 2 has a more intense color. This suggests that there are still many other proteins left in the whey after the release of casein. Therefore, whey is also a useful and nutritious product.

Experience 6 "Detection of carbohydrates in milk"

Target: check if there are carbohydrates in milk.

Equipment: refractory cup, heating device.

Working process: 1. A little whey should be poured into a cup. 2. Evaporate the liquid.

Result: after the liquid evaporated, the whey charred and a sweet odor appeared, similar to the smell of burnt sugar.

Conclusion: proved that there are carbohydrates in milk.

Carbohydrates are the main source of vital energy for a person of any age.

General conclusion:

1. Milk samples 1 and 2 contain the main food substances - proteins, fats and carbohydrates.

2. Whey is a healthy and nutritious product, as it contains proteins and carbohydrates.

3. Cottage cheese (casein) is a useful product, but almost entirely consists of proteins. Use with caution in people who have poor protein absorption.

Experience 7 "Cute ink"

Target: apply practically milk as sympathetic ink.

Equipment: sheet of paper, some milk, cotton swab, iron

Working process:

1. Write milk words on a piece of paper. 2. Gently iron this sheet of paper with a not very hot iron until the text appears.

Result: a distinct brown inscription appeared.

Conclusion: milk can be used for cryptography.

	Milk sample 1 "Vkusnoteevo"	Milk sample 2 Milk from "your cow"
Appearance	Homogeneous, without impurities, precipitation, flakes	Homogeneous, without impurities, precipitation, flakes
Milk color	White color bluish, opaque	Creamy white, opaque
The smell of milk	is absent	is absent
The taste of milk	Sweet-salty	Delicate, sweet-salty
Consistency	Liquid, homogeneous	Liquid, homogeneous
Fat spot diameter
Color when reacting to protein	light purple	Violet
Did you manage to get a precipitate of casein	casein received	casein received
Serum color	light green

2.3. Stage III. Determination of the presence of dangerous microorganisms in the composition of milk.

Target: determine the presence of dangerous microorganisms in milk.

Equipment: sterile milk jars

Working process:

1. Pour milk into jars and cover with lids. 2. Put in a warm place for souring.

Conclusion: there are no dangerous microorganisms in samples 1 and 2.

III. Conclusion

So, in the course of working on the topic of my research, the tasks set were completed and the goal was achieved. The hypothesis that there are ways to check the quality and composition of milk at home was confirmed.

Using various sources of information, I studied what milk is, its composition and properties: what basic food substances are contained in milk and what they are intended for. I got an answer to the question why mammals feed their young with milk. I found out that milk is not only baby food. It is also useful for an adult.

I learned what experiments can be done at home in the kitchen without special equipment and reagents to determine if milk is fresh and if it is suitable for food. He also experimentally studied the composition of milk without special equipment and reagents and found out that any cow's milk contains the main food substances: fats, proteins, carbohydrates that people of all ages need as a source of energy, building material, etc.

He studied and compared the data of experiments, drew conclusions.

IV. Findings:

1. It is important for human health and safety to be able to examine the quality and composition of milk.

2. You can and should check the quality and composition of milk at home

3. Milk is a very useful product, but it must be used with caution.

4. Milk of a local producer (village of Kolyupanovo)

and milk brand "Vkusnoteevo" 1.5% - healthy and safe for humans.

I would like to express my special gratitude to the IAS "Intellect of the Future" for the opportunity to use electronic resources.

V. References

1. Big book of questions and answers. What? What for? Why? / Translated by K. Mishina, A. Zykova.-M: Eksmo Publishing House, 2003

2. N.P. Mogilny, L.A. Trushkina "All about milk and sour-milk products" / www.elinahealthandbeauty.com

3. Kutsenko G.I., Kononov I.F. School food. M.: "Medicine", 1987.

4. Korostelev, N. B. Education of a healthy student / N. B. Korostelev. - M.: Enlightenment, 2002. - 73 p.

5. Bezrukikh M.M., Filippova T.A., Makeeva A.G. Formula proper nutrition. M.: OLMA Media Group, 2009.

Site www.omoloke.ru

Website "Potomu.ru" www.potomy.ru

The naturalness and freshness of milk is not only a problem for those who like to drink it fresh. Quality drink - necessary condition for self-preparation of healthy fermented milk products: yogurt, curdled milk, cottage cheese and so on. There are several effective ways, allowing you to check the quality of milk at home.

Quality requirements: what should be a natural product?

GOST establishes the following conditions for the naturalness of milk:

after milking;
without extracts;
without additives of dairy and non-dairy components;
purified from mechanical impurities;
chilled to 4°C.

Milk that meets all of the above parameters is called whole milk. Today, it is easiest to find at a farmers' market or buy directly from dairy cow or goat owners. Nevertheless, you should not think that only unnatural milk is sold in the store. You can find a high-quality product, but manufacturers, before putting the goods into retail networks, first normalize it - they lead to common standard fat content by adding whole milk or cream to skimmed milk.

Determination of milk freshness

The shelf life of homemade and factory milk is different. A sour product is easy to recognize by its sharp sour smell. If it is not there, but there are suspicions of stale milk, you can confirm or refute the guesses with very simple steps.

Way for the brave

For those who aren't too picky about off-flavours, just try some milk. A sour taste indicates that it is stale.

boiling liquid

A small amount of milk can be poured into a saucepan and brought to a boil. Did the liquid curdle when it boiled? So the product is sour.

Identification of a sour drink with soda

Sour milk releases acid, and soda reacts to it. Pour half a teaspoon of sodium bicarbonate into 100 ml of the drink. Did the liquid froth and bubble? This product is not worth drinking.

Checking the naturalness of the composition

Non-dairy additives in milk are an unfortunate reality in today's dairy market. The pursuit of profit does not imply concern for the health of the consumer. This state of affairs literally forces the buyer to acquire minimal skills to independently determine the quality of products.

Modern additives are very diverse. Basically, their purpose is to preserve the freshness of the product for as long as possible, increase the volume, and add more fat. At home, it is easy to identify a gross fake, although some methods will require chemical reagents, which can be purchased at specialized stores and pharmacies.

Is the milk diluted?

The most common trick for increasing the volume of milk is diluting it with water. Simple manipulations will help to understand whether the product is diluted or not.

Use vodka or alcohol

You will need:

alcohol or high-quality vodka;
saucer.

Mix two parts of alcohol (vodka) with one part of milk. Shake well for 1 minute. Then quickly pour the "cocktail" onto the saucer. Wait a little - 5-6 seconds. If flakes form in the liquid during this period, then there is no water in the milk. A slower separation of the alcohol-milk mixture indicates the addition of water to the product by the manufacturer. Depending on the time, the approximate percentage of dilution is established:

1 minute - 20% water;
15–35 minutes - 40% water;
40 and more - 50% water;

The method is not suitable for testing goat milk, since it lacks casein - it is this protein that coagulates during the experiment under the influence of alcohol.

We use the "milk drop" method

You will need:

paper napkin;
match.

A match is lowered into well-mixed milk, the resulting drop is taken out and deposited on a napkin. The drying speed of a wet circle formed around a milk drop will tell you whether the liquid is diluted or not:

whole milk - the diameter of the spot almost corresponds to a drop and dries out for more than 2 hours;
10% water - wet circle dries in 1 hour;
30% water - the wet border is wide and dries within 30 minutes;
50% water - the drop does not hold a convex shape, dries quickly (no longer than 20 minutes).

Testing with warm water

You will need:

cup;
warm water.

In a glass with warm water pour milk in a thin stream. The undiluted product will not immediately mix with the liquid, but will rise to the top. Diluted milk will dissolve easily in warm water.

Is there starch in the liquid?

Unscrupulous milkmen condense skim milk with starch, thereby passing it off as fatter.

You will need:

tablespoon.

Add a couple of drops of iodine to a tablespoon of milk. The starch present in the product will cause a reaction - the liquid will turn blue. If the color of the milk becomes yellowish, there is no starch in it.

Did the manufacturer add chalk, plaster or soda?

With soda, some businessmen are reinsured from the rapid souring of a healthy drink.

You will need:

Acid method. Half fill the glass with milk, then add half a teaspoon of vinegar or lemon juice. Hissing and bubbles indicate the presence of chalk, gypsum or soda.

Dye method. Pour a small amount of milk into the test tube, then carefully, without shaking the container with the liquid, add 7–8 drops of the indicator along the wall. If soda is present in the composition of the dairy product, the liquid will turn dark green.

Are there any antibiotics in the product?

Antibacterial drugs prevent the growth of pathogenic microorganisms, which increases the shelf life of dairy products. You can tell if an antibiotic has been added to milk by fermenting it. A teaspoon of sour cream or kefir is added to a glass with a drink and left at room temperature for a day. By the end of the mentioned period, the natural product will turn into curdled milk. If the milk does not react to the leaven, the development of lactic acid bacteria is inhibited by antibiotics.

Is there aspirin or boric acid in the drink?

Aspirin in milk is a scam to prolong the product's freshness, which poses a serious threat to the health of people with aspirin intolerance. Additives in the form of salicylic, acetylsalicylic and boric acid easily detected with litmus paper. The color of the indicator after dipping into milk with the listed components changes to red.

How to detect palm oil?

Palm oil improves the taste of the reconstituted drink, and also increases the shelf life. But no matter how many methods of detecting vegetable fat in milk with improvised means walk on the Internet, this component can only be detected in laboratory conditions using gas chromatography. Therefore, it is more effective to protect yourself from an unnatural product by carefully studying the labeling, being critical of the low price and no less careful choice of a trustworthy manufacturer.

Establishment of fat content and acidity

The fat content of milk bought in bulk or in standard packaging is easy to determine on your own. For this, in addition to milk, you will need:

ruler;
a tall glass without a pattern or a test tube.

With a ruler from the bottom you need to measure 10 cm and put a mark. Then you need to pour milk into a glass exactly up to the mark and leave it in a warm place for 8 hours. When the product settles, a layer of cream will appear on top. It must be measured in millimeters as accurately as possible. The calculation is carried out according to the following formula: 1 mm of cream = 1% fat. Therefore, if their height is 5 mm, then the fat content of the entire drink is 5%.

Information about the acidity of milk is necessary for those who are engaged in home cheese making. To determine it, there are special ready-made tests. At home, you can also calculate the acidity of the product using phenolphthalein, distilled water and sodium hydroxide.

Sequencing:

Pipette 10 ml of milk into a test tube.
Add 20 ml of distilled water and 3 drops of phenolphthalein.
Gradually lower into the contents of the test tube 0.1 solution of normal sodium hydroxide until a slightly pink color is obtained.
Calculate the amount (in millimeters) of sodium hydroxide used to obtain a faint pink color.
Multiply the result by 10 - this will be an indicator of the acidity of milk in degrees.

The acidity of milk is measured in Turner degrees. For a natural product of the highest and first grade, 16–18 ° T is considered the norm; the second grade - from 18 to 20°T; off-grade milk - 21°T.

Is it possible to test dry milk?

Powdered milk is often used in home cooking, baby food and bodybuilding diets. Before evaluating the taste of a reconstituted product, it is advisable to test it dry. Here's what you need to pay attention to first:

Texture. The powder of high-quality milk powder is fine, homogeneous. Possible lumps are easily scattered when lightly pressed with a finger. Violation of storage conditions leads to caking of the powder. This product is not worth buying.
Colour. The powder should be white, a light cream shade is possible. Intense creamy color, brown blotches indicate the burning of milk during the drying process.
Smell and taste. At good product it is purely milky, sometimes with a taste and smell of boiled milk.

High-quality powder with a high protein content should not precipitate when diluted with water.

Video: How to check the quality of a drink at home?

I would like to believe that in the near future the “milk deception” will end, and consumers will only be interested in the freshness and fat content of the drink, and not in possible additives. In the meantime, you can use proven methods to check the quality of the product.

Scientific and practical conference

students

"I AM THE RESEARCHER"

My natural world - scientific research(the world).

"STUDYING THE QUALITY OF MILK IN HOME CONDITIONS"

Saygushev Ivan Alexandrovich

2nd grade student

Supervisor:

Kazakova Larisa Alexandrovna

primary school teacher

MOU Mordovo - Beloklyuchevskoy secondary school

Milk is a rich source of easily digestible protein, which is a plastic material.
It is a rich source of calcium and phosphorus, a guarantee of strong bones and healthy teeth.
This is a source of milk fat - so useful for the structure of the child's body, a source of energy.
This is a delicious sweet carbohydrate - necessary for the active activity of children - a source of easy energy.
Milk is lacteins that have antimicrobial activity.

Purpose of the study:

- to study the meaning and composition of milk; learn to distinguish a high-quality product from a low-quality one.

Tasks:

- using various sources of information, determine the importance of milk for a growing organism;

- to enrich knowledge about milk as a valuable and useful product for the growth of the child's body.

- with the help of experiments with milk to investigate its composition.

Hypothesis

“Milk is an amazing food prepared by nature itself” (academician I.P. Pavlov).

Problem

Many children do not like milk and

milk products.

Interesting facts about milk.

Different cultures have their own traditions of using dairy products, their own types of milk, and we will give a few interesting facts about this wonderful product.

1. The most consumed type is cow's milk. It is produced in the world annually more than 400 million tons. At the same time, each cow gives 11-23 liters, that is, an average of 90 glasses per day. As a result, one cow produces 200,000 glasses of milk in her lifetime. At the same time, cow's milk is usually 85-95% water, and fats, proteins and carbohydrates make up the remaining share.

2. Another popular type is goat milk. It is used to make rocamadour, caprino and feta cheeses.

3. The fattest milk is in seals (more than 50% fat) and whales (about 50% fat). And the most “lean” is the milk of mares and donkeys.

4. Unique properties has camel milk. It doesn't curdle and has a lot more vitamin C than cow's. Camel milk is the staple food for desert dwellers.

fermented baked milk
condensed milk
cream
butter
sour cream
powdered milk
serum
cottage cheese
baked milk
shubat

ayran
acidophilus
Varenets
katyk
yogurt
kefir
koumiss
matsun
buttermilk
curdled milk

Practical research

Who does not consume milk and dairy products at all?

Bibliography

1 I know the world. M.6 "AST" 1997 2. Konkov VP What do we know about the cow. Stories about Pets and Animal Husbandry: Popular Science Book - Irkutsk: East Siberian

book publishing house, 1990

3. Kugenev P. V. Milk and dairy products. - 3rd ed., - M., Rosselkhozizdat, 1985 Internet resources 4. http://www.medical-enc.ru/12/moloko_child.shtml

5. http://www.pritci.ru/publ/46-1-0-2832

6. http://leg-mif.narod.ru/playcast/cast_22.html

7. http://lamacompany.ru/publ/3-1-0-24

8. http://absurdopedia.wikia.com/wiki/Cow

10. http://wap.krilja.forum24.ru/?1-4-0-00000031-000-0-0-1267705455

11. http://ru.wikipedia.org/wiki/Troll

12. http://dmitrid.mylivepage.ru/wiki/645/270 About cows

13. http://www.xrest.ru/tag/nature._flowers/346/

14. http://nat-prod.ru/animal/cow/179-kak-pravilno-zapustit-korovu.html

15. http://basik.ru/handmade/?PageNum=4