Chemical analysis of chocolate. Hello student Studying the composition and quality of milk chocolate

Introduction………………………………………………………………………3

General information about chocolate…………………………………………..4

1. The history of chocolate…………………………………………….....4

   Classification and assortment of chocolate……………………...6

   Chocolate production……………………………………………9

   The chemical composition of chocolate………………………………….13

   Quality requirements………………………………………….14

   Chocolate storage conditions…………………………………...14

2. Examination and quality of the finished product…………………………….16

2.1. Chocolate quality indicators…………………………………16

2.2. Sampling and preparing them for analysis………………………...22

2.3. The procedure and methods for conducting the examination…………………....23

Conclusion………………………………………………………………...25

References………………………………………………………..26

Appendix 1……………………………………………………………...27

Introduction.

Chocolate is a divine nectar, because they used to drink it. And today they not only drink and eat, but sculpt sculptures from it, make souvenirs, “dress it up” at fashion shows and even wrap it in spa salons. It is simply given and, finally, huge money is earned on it.

Chocolate has been and will be relevant and will never go out of fashion. He will be loved by different generations from small to great. Why do I think so? Yes, because I myself am a big fan of this unique temptation. Yes, I do not deny that chocolate can change, but there is no way not to leave our lives, it is firmly hooked in it. And we do not provide how we would live without it! Chocolate is suitable for all occasions, both on holidays and on weekdays.

The purpose of my course work is not only to learn general information about chocolate, to consider chocolate quality indicators, but also to study the procedure and methods for conducting chocolate examination.

1. General information about chocolate

1.1. History of chocolate

The history of chocolate, so familiar to us now, began a very long time ago, more than 3000 years ago.

Around 1500 BC, the Olmec civilization arose in the lowlands along the Gulf of Mexico in America. Their culture has left us very little, but some linguists believe that the word "cacao" first sounded like "kakawa" around 1000 BC, at the height of the Olmec civilization.

The Olmecs were later replaced by the Mayan civilization. The Mayan ancestors arrived in the lowlands of northern Guatemala around 1000 BC. Until then, they lived in the highlands of Guatemala and the Mexican province of Chiapas. There, cocoa seems to have been very rare, if known at all. Be that as it may, having descended from the plateaus, the Mayans discovered and began to cultivate a wild-growing cocoa tree, and it was during that period that the modern pronunciation of the word "cocoa" most likely arose.

Around 250 AD, the development of Mayan culture entered its classical phase. By the 600s of our era, the Maya planted the very first cocoa plantations known to us. Formidable Mayan cities were erected, with their pyramid castles and cruel rulers. Until their fall in the 9th century AD, the architecture of the Mayan cities surpassed that of ancient Greece and Italy during the early Renaissance. Chocolate was a luxury and a sacred drink for the Maya, not only in life but also in death.

They had well developed methods for making chocolate drinks of various kinds using various additives. One of the main ingredients was pepper and cloves.

Many books about chocolate say that it was the Aztecs who first cultivated cocoa trees and invented the chocolate drink. As we have said, this is not true. The Aztecs nevertheless played a large role in the expansion of the use of cocoa in the New World. Aztec legend says that cocoa seeds came to us from Paradise and that wisdom and strength come from the fruit of the cocoa tree. The map shows the border of the Aztec empire in 1519 - before it was destroyed by the Spaniards. The most important territory was the area of ​​Xoconochco, which the Aztecs conquered through expansion between 1486 and 1502. This gave the Aztec empire access to the best cocoa plantations. The area of ​​Xoconochco was isolated from the rest of the Aztec empire, so long distance traders played a very important role in transporting cocoa beans to the Aztec capital, Tenochtitlan. Cocoa beans served in the Aztec empire as money. It is said that Christopher Columbus brought cocoa beans to King Ferdinand from his fourth expedition to the New World, but no one paid much attention to them due to the large number of other treasures brought by Columbus. In the next 100 years after Columbus, chocolate appeared in Europe. Costing 10-15 shillings a pound, chocolate was considered a drink for high society. In the sixteenth century, the Spanish historian Oviedo wrote: "Only the rich and noble could afford to drink chocolate, as he literally drank money. Cocoa beans were used as currency by all nations; ... for 100 of these cocoa seeds it was quite possible to buy a good slave" .

Chocolate was also used as a remedy by the leading healers of the time. So, Christopher Ludwig Hoffmann recommended chocolate as a remedy for many diseases, referring to the experience of treating Cardinal Richelieu. With the development of industry, chocolate became more accessible, various additives began to be added to it: milk, spices, various sweet substances, wine and even beer. If initially chocolate was considered exclusively a male drink, later it became a favorite children's drink. In 1674, rolls and cakes were made using chocolate. This date is considered the date of the appearance of "edible" chocolate, which could not only be drunk, but also eaten.

Cocoa imported to Europe first goes to monasteries and to the King's Court, where it is very popular with court ladies. From Spain, "xocolatl" penetrates into Europe, quickly displacing Mexican spices made from cane sugar and vanilla. The government of the German emperor Charles V, aware of the commercial importance of cocoa, demands a monopoly on this product. However, already in the 17th century, smugglers were actively importing it into the Netherlands. The first licenses for the creation of chocolate production are invented by the Italians. In England "Chocolate Houses" are more visited than coffee and tea salons. In the 19th century, the first chocolate bars appeared, and Jean Neaus invented the first candy with praline filling.

1.2. Classification and assortment of chocolate

Chocolate is a product of processing cocoa beans with sugar.

Chocolate contains:

carbohydrates - 5-5 5%);

fat - 30-38%;

protein - 5-8%;

alkaloids (theobromine and caffeine) - approximately 0.5%;

tannins and minerals - approximately 1%.

Energy value (per 100 g of product):

chocolate - 680 calories;

chocolates - 460 calories;

cocoa - 400 calories.

Chocolate contains phenylethylamine, tryptophan and anandamide (substances that affect the emotional centers of the brain and create a feeling of love in the human body), magnesium and iron.

The composition of modern chocolate varieties, in addition to cocoa beans and sugar, includes skimmed milk powder, glucose syrup, vanilla or vanillin, ethyl alcohol syrup, inverse sugar, vegetable (nut) oils, nuts (hazel, hazelnuts, almonds), lecithin, pectin, natural or artificial flavors, preservatives (sodium benzoate), citric acid, orange and mint oils.

Cocoa beans are 50% cocoa butter, which at a temperature of 22-27 ° C is hard and brittle, and at a temperature of 32-36 ° C begins to melt, i.e. its melting point is below the temperature of the human body. Therefore, real chocolate melts quickly in the mouth and does not leave a feeling of viscosity. Chocolate should not contain other fats other than cocoa butter. Additives such as milk fat, palm, coconut or peanut oils significantly degrade the quality of this treat.

bitter - more than 60%;

semi-bitter (dessert) - about 50%;

dairy - about 30%.

A bar of milk chocolate contains 15% cocoa butter, 35% sugar and 20% milk powder, semi-bitter - 45% sugar and up to 5% cocoa butter, and bitter - 40% sugar.

Chocolate is classified:

in shape and size;

depending on its composition and method of processing the chocolate mass.

According to the shape and size, chocolate is distinguished in 100g bars. and smaller, chocolate bars, curly weight up to 250g., chocolate medals, patterned chocolate - flat relief figures of small size (usually included in "Chocolate set" sweets).

Depending on the recipe and processing method, chocolate is divided into:

ordinary with and without additions;

dessert with and without additions;

with fillings;

diabetic (sugar is replaced by sorbitol or xylitol);

Ordinary chocolate is produced from any cocoa beans (with a predominance of consumer), without conching. Therefore, it has lower taste and aromatic qualities, less fine dispersion (92%). The sugar content in it is not more than 63%.

Dessert chocolate is produced only from noble varieties of cocoa beans with long conching. Therefore, it has high taste and aromatic qualities, fine dispersion (96-97%). The sugar content in it is not more than 55%.

Porous chocolate is produced, as a rule, from the dessert mass by vacuuming, it has increased fragility and tenderness.

Chocolate with filling is produced, as a rule, from ordinary chocolate mass in the form of bars, bars and figures (shells, horns, horseshoes, etc.). The content of filling for chocolate in the form of loaves - not less than 35%, for chocolate with a net weight of more than 50g - not less than 20%.

Powdered chocolate is made from cocoa mass, vanillin and powdered sugar with and without the addition of dairy products. It is intended for preparing a drink by diluting with hot water or milk in a ratio of 1: 1 or 1; 2 (to taste).

Couverture - liquid chocolate, used for glazing sweets, waffles, marshmallows. Fat should be 34-37%.

White chocolate is produced, as a rule, from ordinary chocolate mass without grated cocoa, i.e. it contains cocoa butter, powdered sugar, milk and flavoring.

Substitute chocolate is represented on the market by confectionery and sweet bars. Confectionery tiles are made from finely ground confectionery mass obtained from cocoa butter substitute fats (solid hydrogenated vegetable fats) with or without cocoa butter, as well as sugar and various flavoring and aromatic additives: apple powder, roasted peanuts, coffee, etc. Sweet tiles are made from the mass obtained by processing sugar and confectionery fat of domestic production with various flavoring and aromatic additives. Assortment: Hello, Palm, Casino, Dairy, Soy with peanuts, Fairy tale, Magic, Mysterious.

Diabetic chocolate is intended for diabetic patients. In it, sugar is replaced by sorbitol or xylitol: Milk with xylitol, Northern Lights.

Chocolate paste - is a homogeneous finely ground plastic mass, consisting of sugar, fat, cocoa powder (at least 12%) with the addition of flavoring and aromatic substances.

1.3. chocolate production

Burning

The chocolate making process begins with the roasting of the beans. They are peeled and roasted to remove any remaining moisture and achieve the characteristic cocoa taste and smell. Gourmet cocoa varieties are roasted at a lower temperature, which gives them a very delicate flavor.

cracking and winnowing

After roasting, the cocoa beans are cooled and then sent to a perpetual machine, which refines them, separates them from the shell and crushes them into particles several millimeters thick. The husk is removed through a sieve by a stream of hot air. The shelled and crushed beans are called crushed cocoa beans.

Mixing

Turning crushed cocoa beans into chocolate by mixing different ingredients is a skillful and secret area in chocolate making. The beans are sorted by origin, roasted and beaten, matched to precise recipes, blended and placed in cocoa grinders.

grinding

Roasted, ground beans, the so-called "feathers", are heated and carefully ground to form a cocoa paste, also called cocoa mass or liquor. It is the main ingredient for the preparation of various chocolate products and consists of cocoa butter (natural cocoa fat) and the dry component of the beans.

Then the cocoa mass is laid out under a hydraulic press for squeezing fat (cocoa butter). The remainder (cake), containing another 20% of the oil, is ground into a powder, which is then carefully sieved, the resulting powder is pure unsweetened cocoa powder. Cocoa butter is filtered, softened, molded and stored. And cocoa liquor is mixed with sugar (and milk powder in the case of making milk chocolate), and the paste is intensively pounded and refined from a grain size of 50 microns to 17.

To make chocolate in cocoa mass, you need to add cocoa butter, sugar, vanilla. These ingredients are mixed and kneaded until a smooth, homogeneous mass is obtained.

Conching

This is one of the most important steps in making super chocolate. Its purpose is to remove all residual moisture, eliminate incompatible flavors and aromas, lumps that are still present, as well as the displacement of volatile acids and excessive bitterness.

The chocolate is put into conching tanks, where it is rolled out and kneaded for 2-3 days. During this process, it is heated to different temperatures. For high quality chocolate, cocoa butter is added along with lecithin (extracted from soybeans) to help reduce viscosity. The conching process removes moisture and promotes smooth, uniform chocolate with enhanced flavor and aroma.

While regular chocolate only takes a few hours to conch, the highest quality chocolate can be conched for up to five days.

Insufficient conching of chocolate can result in mediocre flavor and high acidity.

Tempering chocolate

In previous processes, the temperature of the chocolate was constantly maintained at the melting point of cocoa butter. Now it is necessary to cool the mass in such a way as to ensure proper cocoa butter crystallization and one-time distribution of the mixture. Tempered chocolate sets quickly, has a good texture and sheen, and is easy to work with.

Coverture, which has a high content of cocoa butter, is tempered, since the compounds of fat molecules are stable at different melting points. In fact, dissolution occurs both at low temperatures and at high ones. But the first thing to do is to bring the coverture to a high temperature, enough to completely dissolve all the fat (if the chocolate is too hot, then its subtle taste will be destroyed). Second, cooling or pre-crystallization of molten chocolate occurs when the chocolate appears to be thick and viscous. At this point, pure fat molecules form (remain as unstable crystals that are immobile). At this stage, the chocolate is too thick for general use. It needs to be heated a little, without deviating from the recommended temperatures.

Collection and processing of cocoa

The cocoa tree belongs to the family Sterculiaceae and grows in the tropical zone known as the "cacao belt". Cacao trees cannot stand direct sunlight, so they are protected by a special awning. Plantations should be located at an altitude of 400-600 meters above sea level. The quality of the soil also plays an important role. It should be rich in nitrogen and potassium, well-drained in areas with heavy rains and, conversely, equipped with water supplies in dry areas. For tree growth, a humid climate (60-90%) and an average temperature of 25 to 28 C are also required.

The fruits of the cocoa tree are called cocoa pods. Young trees usually begin to bear fruit after 3-5 years. A cocoa pod weighs approximately 200 to 800 g and bursts with a dry crack when ripe after 5 to 6 months. During this time, it changes in color from green to yellow and from red to orange.

The height of cocoa trees ranges from 5 to 7 meters, and the life span is from 25 to 30 years. Cocoa trees can be found throughout the equatorial belt, where the average temperature is 26 ° C and high humidity. They can also be found in the wild: animals, eating their fruits, scatter cocoa beans on the ground, as a result of which they germinate.

The leaves of the cocoa tree are large (20-40 cm long and 7-12 cm wide). When the tree is 3-4 years old, it blooms with white flowers (1 cm in diameter). On average, the tree produces 30 pods, each containing 30 to 40 beans embedded in the white pulp of the fruit. There are several types of cocoa.

In regions with a very humid climate, lucky for the rains, cocoa can be harvested all year round. But in many countries there are only two harvest seasons: November-January and May-July. During harvest, each pod is cut open with a machete and can contain up to 40 cocoa beans surrounded by a sweet white film called mucilage.

After splitting, the beans and white pulp are removed from the pod and then covered with banana tree leaves. Within 1-2 weeks, the fermentation process takes place. This is a very important process. And its improper conduct can adversely affect the taste of chocolate.

After fermentation, cocoa beans contain approximately 60% moisture. It must be reduced to at least 7.5% to eliminate the possibility of damage during transportation. Therefore, fermented beans are laid out under the sun on special mats or pallets, which should be immediately covered in case of rain. The drying process contributes to the elimination of bitterness and the appearance of a specific cocoa aroma. (See Appendix 4)

1.4. The chemical composition of chocolate

The main components of the dry matter of cocoa beans are fats, alkaloids - theobromine, caffeine in (in small quantities), proteins, carbohydrates, tannins and minerals, organic acids, aromatic compounds, etc.

Fat (cocoa butter) is contained in the amount of 52-56% dry matter. At a temperature of 25 C, cocoa butter is hard and brittle, and at 32 C it is liquid, so it melts in the mouth without leaving any residue. The chemical composition of the product "milk chocolate"

Nutrients, vitamins, trace elements per 100 g:

Water: 0.9 g

Proteins: 6.9 g

Fat: 35.7 g

Carbohydrates: 52.9 g

Mono- and disaccharides: 49.5 g

Starch: 2.9 g

Dietary fiber: 2.0 g

Organic acids: 0.5 g

Ash: 1.6 g

Vitamin B1: 0.05 mg

Vitamin B2: 0.3 mg

Vitamin PP: 0.5 mg

Iron: 1.8 mg

Potassium: 543.0 mg

Calcium: 187.0 mg

Magnesium: 38.0 mg

Sodium: 76.0 mg

Phosphorus: 235.0 m

Calories: 547.3 kcal

1.5. Quality requirement

Chocolate must comply with the requirements of GOST 6534-69. The taste and aroma are clearly expressed, characteristic of this species. Color from light brown to dark brown, for white chocolate - cream. The shape is correct, without deformation, in the form of tiles, loaves and various figures, both with and without a pattern. The front surface of the chocolate should be shiny, without sugar and fat bloom, in chocolate with milk - slightly dull, in chocolate with unground additions, the underside of the bar with an uneven surface. The consistency should be solid, the structure should be homogeneous, the fracture should be matte, for porous chocolate - cellular. Additions that are not introduced in a finely ground form are evenly distributed in the chocolate mass.

1.6. Storage conditions for chocolate

Store chocolate at a temperature of 18C and a relative humidity of 75%. Under these conditions, chocolate is stored for the following warranty periods from the date of production:

dessert and ordinary without additions - 6 months,

weight without additives not wrapped - 4 months,

dessert and ordinary with additions, chocolate with filling and in powder without additions - 3 months,

weight with additions not wrapped - 2 months, white chocolate and in powder with the addition of dairy products - 1 month.

Storage of cocoa beans. Dried cocoa beans should be placed in the warehouse as soon as possible. Before being transported to foreign port terminals or chocolate factories, the beans must be carefully checked, packed in special ventilated containers and placed in a well-ventilated ship hold. After being added to the factory, the cocoa beans are carefully checked to identify possible specific defects, as well as defects in taste and aroma, to check for the presence of foreign bodies, and finally to control the acceptable moisture content.

The packaged beans are then placed in a clean, dry environment and stored at about 16°C.

2. Expertise and quality of the finished product.

2.1. Indicators of chocolate quality.

The quality of chocolate is evaluated by the following indicators:

Organoleptic;

Physico-chemical;

security;

Microbiological.

Organoleptic indicators.

Organoleptic indicators that characterize the quality of chocolate include appearance, shape, texture, structure, taste and smell.

Table 1.

Organoleptic quality indicators of chocolate

Name indicator	Characteristic
Taste and smell	Typical for this product, without foreign taste and smell
Appearance	The front surface is shiny. For chocolate medals, chocolate with finely ground additions of dairy products and nuts, chocolate molded into foil and by weight, a matte surface is allowed. In chocolate with large additions in the form of whole or crushed nuts, chopped candied fruits, raisins, exploded cereals, etc. and porous, an uneven surface is allowed. Graying and damage by pests of grain stocks is not allowed. Broken products are allowed: no more than 4.0% - for chocolate with fillings; no more than 2.0% - for chocolate with large additions. For weight expanded chocolate, scrap is allowed in different measure 1/3 of the tile, smaller scrap should not exceed 3.0%.
	Compliant with the recipe, no deformation for all types of chocolate, except by weight
Consistency
Structure	Homogeneous. For porous chocolate - cellular.

physical and chemical indicators

Physical and chemical indicators include the degree of grinding, the mass fraction of the filling, the mass fraction of ash.

Table 2.

Physical and chemical indicators of chocolate quality

Name of indicator	Norm for chocolate
	ordinary		dessert
	No Additions	With additions	No Additions	With additions
Grinding degree, %, not less than
Mass fraction of filling, %, not less than: for chocolate in the form of loaves for chocolate net weight St. 50g
Mass fraction of ash insoluble in hydrochloric acid solution with a mass fraction of 10%, %, not more than

Mass fractions of sugar, fat, filling and moisture in chocolate should be in accordance with the calculated content according to the recipe, taking into account the allowable deviations.

The mass fraction of total sugar (in terms of sucrose) in diabetic chocolate should be in accordance with the calculated content according to the recipe and the maximum deviation from the calculated upwards of 5.0%, but not more than 9%. The mass fraction of cocoa products in chocolate, depending on the recipe, must be at least 25.0%. The amount of filling should not exceed 50% of the chocolate mass. In fillings for chocolate, moisture is normalized, and for nut, chocolate and chocolate-cream fillings, the fat content.

The moisture content of chocolate without additives and dessert chocolate with additives should not exceed 1.2%, milk chocolate - 2% (with a dry whole milk content - no more than 3%), chocolate with fruits - 5%, and ordinary chocolate with additives - 1.5%.

In chocolate, the fiber content is limited: in chocolate without additions - no more than 3%, with additions - no more than 4%. The content of ash insoluble in a 10% hydrochloric acid solution is not more than 0.1%.

Safety performance

Depending on the nature of impacts, safety, there are chemical, radiation, mechanical, sanitary and hygienic, etc.

Substances affecting the chemical safety of food products, including chocolate, are divided into the following groups: toxic elements (heavy metal salts); mycotoxins; nitrates and nitrites; pesticides; antibiotics; hormonal drugs; higher alcohols and aldehydes; esters; furfural and hydroxymethylfurfural; monomers; prohibited food additives; dyes for packaging.

The admissibility of the content of toxic elements in chocolate is established according to the standards: GOST 26927-86, GOST 26930-86-26934-86. Exceeding the maximum allowable concentrations of such elements can cause poisoning of varying severity, sometimes even fatal.

Permissible levels of toxic elements, mycotoxins, pesticides and radionuclides in chocolate are shown in Table 3.

Table 3

Permissible levels of toxic elements, mycotoxins, pesticides, radionuclides in chocolate

As indicators of the radiation safety of food products, MPCs (maximum permissible concentrations) of radioactive isotopes of cobalt, cesium and strontium (Co 60; Cs 90), as well as radionuclides, are established.

Sanitary and hygienic safety - the absence of an unacceptable risk that can occur with various kinds of biodamage to chocolate. Biodamages include microbiological and zoological damage.

microbiological indicators

Microbiological damage (diseases) is caused by a variety of microorganisms. Distinguish between bacterial and fungal infections. In some cases, products accumulate toxic substances (mycotoxins - with mold, salmonella, staphylococcus, E. coli, etc.), which cause human poisoning of varying degrees, sometimes with a fatal outcome.

Microbiological quality indicators of chocolate are disclosed in Table 4.

Table 4

Microbiological indicators of chocolate quality

Product group	QMAFAnM CFU/g, no more	Mass of the product, g, in which it is not allowed		Yeast, CFU/g, no more	Molds, CFU/g, no more
		BGKP (coliforms)	Pathogenic, incl. salmonella
Chocolate ordinary and dessert without additions
Plain and dessert with additions
with fillings

Biodamages of the second group should be called zoological, as they are caused by various representatives of the animal world (insects, rodents, birds). The result of such biodamage is not only quantitative losses, but also a loss of safety, since damaged goods are contaminated with excrement (feces) of insects, rodents and birds, and can also be infected with pathogenic microorganisms.

2.2. Sampling and preparation for analysis

Sampling and preparation of laboratory tests of chocolate is carried out in accordance with GOST 5904-82 "Confectionery products. Rules for acceptance, methods of sampling and sample preparation."

To control the organoleptic and physico-chemical indicators of the quality of chocolate from different places of each unit of transport packaging in the sample, the following are selected:

1 tile - with a net weight above 100g;

3 tiles - with a net weight of 51 to 100g inclusive;

The combined sample is divided into 3 parts, one of which is sent to the laboratory for testing, and two are left as controls for re-testing.

Samples in the form of jars, tiles, packs are wrapped in thick paper and tied with twine.

Other samples are placed in dry clean glass jars with ground glass or rubber stoppers, packed in plastic boxes with screw caps or wrapped in parchment (cellophane, polymer films).

Prepared samples are sealed and accompanied by a sampling report indicating:

serial number of the sample;

product name;

name of the manufacturer and its address;

batch or wagon numbers;

sample mass;

lot size;

the type of products for which the batch is sent;

names and positions of the persons who sent the sample.

In the process of preparing chocolate samples for laboratory testing, it is ground on a grater or mechanical grinder and placed in a tightly closed container.

When examining chocolate with filling or chocolate figures, samples are prepared with the division of products into component parts. The body of the products is completely separated from the glaze. The icing is placed in a sealed container. A separate body is crushed, mixed and also placed in a special bowl. The mass of a chocolate sample without separating the product into its component parts must be at least 100 g, with the destruction of products into its component parts - at least 200 g.

2.3. The procedure and methods for the examination of chocolate

Organoleptic evaluation of chocolate is carried out according to GOST 5897-90, determination of the degree of grinding - GOST 5902-80, mass fraction of filling GOST 5897-90, ash - GOST 5901-87, toxic elements - GOST 26927-86, GOST 26930-86 - GOST 26934-86 .

Organoleptic evaluation of chocolate is carried out at a temperature of 16-18°C. It begins with a visual inspection of the packaging and labeling. Set the clarity of the picture and inscriptions, the brightness of the colors of the label and its artistic merit, the density of the wrapping. The date of production of chocolate and compliance with the warranty period of storage is checked by a stamp or a composter on a foil or liner. Then the net mass of chocolate is checked by weighing it without foil and labels with a resolution of up to 0.01 g.

Appearance is determined by the condition of the front and bottom surfaces of the chocolate. The front surface of chocolate without additives should be shiny without a grayish coating and spots; with additions can be slightly dull. It is not allowed to leave the filling on the surface of the chocolate. Consistency at 18°C ​​is solid. The structure of chocolate without additions and with finely divided additions is homogeneous, porous-cellular. Coarsely ground additions (waffles, nuts) should be evenly distributed in the mass. The shape of the chocolate bars and figures must be correct, without deformations. Taste and aroma are determined by sampling. They should be clearly defined, with a subtle chocolate or vanilla aroma from additives and a pleasant bitterness. Chocolate with additions should have a harmonious taste.

Conclusion.

In conclusion, it is worth saying a few words about the beneficial properties of this miracle product. In scientific terms, chocolate is valued for its high content of magnesium, phosphorus, iron, calcium, polyphenol, theobromine, caffeine, etc., as a means of stimulating the central system, muscle tone, and also as a powerful antioxidant. Speaking in the language of the layman, the use of chocolate is, first of all, a source of pleasure, a great way to improve mood and tone. True, recent studies show that chocolate does not affect everyone in the same way. Irritable and suspicious people can even worsen their condition by eating it in kilograms.

It is said that you can determine the character of a person by what kind of chocolate he prefers. So, lovers of milk chocolate are dreamy people, dark chocolate lovers are materialists firmly standing on the ground, and white chocolate lovers are people with an active position.

In this work, I disclosed general information about chocolate, examined the quality indicators of chocolate and studied the procedure and methods for conducting chocolate examination.

Bibliography.

1. Kauts E.V. "The Way to Success", Nutrition and Society, No. 4, 1998.

2. Shevchenko V.V. Commodity research and examination of consumer goods. Moscow: Infra-M, 2003

3. V.I. Khlebnikova Technology of production of food products. M.: Academy, 2007. - 345 p.

4. Shepelev A.F., Pechenezhskaya I.A. Commodity research and examination of food products: Textbook. - Moscow: ICC "Mart"; Rostov-on-Don: Publishing Center "Mart", 2004. - 992 p.

5. GOST 6534-89 Chocolate. General specifications.

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Introduction

Nowadays chocolate is one of the most common food among people. In almost every store, anyone can buy a bar of chocolate. But chocolate can be approached not only from a consumer point of view, but also from a research point of view, choosing it as an object of chemical analysis.

Objective of the project : to study the chemical composition of different brands of chocolate and study its effects on human health.

Research objectives:

1. Get to know different types of chocolate.
2. To study the chemical composition of chocolate of different varieties.
3. Conduct a qualitative analysis of the studied samples of chocolate products.
4. Compare their chemical composition.
5. To study the effect of chocolate on human health.
6. Conduct a survey among classmates about the dangers and benefits of chocolate.
7. Find out how chocolate is currently used in medicine and cosmetology.

Object of study: chocolate.

Subject of study: chemical analysis of the composition of chocolate.

Project type Key words: individual, long-term, interdisciplinary (chemistry and biology), experimental.

Forms for presenting project results: report, presentation.

Literature review

Chocolate - (English Chocolate, French Chocolat, Spanish Chocolate ) is a term denoting various types of confectionery products made using cocoa fruits. One of the most common confectionery products. It contains proteins, fats, carbohydrates, tannins, alkaloids caffeine and theobromine. It is prepared on the basis of cocoa products.

E name thymology:The word "chocolate" comes from "chocolatl", the name of a drink made from cocoa beans. In the Aztec language, "chocolli" means "bitterness" and "atl" refers to the water used to make a chocolate drink.

GOST No. 6534-69

According to the state industry standard No. 6534-69, chocolate is:

1. taste and aroma clearly expressed, characteristic of this species
2. color from light brown to dark brown, for white chocolate - cream
3. form correct, without deformation, in the form of tiles, loaves, various shapes, both with and without a pattern
4. front surface chocolate should be shiny, without sugar and fat bloom, in chocolate with milk - slightly dull, in chocolate with unground additions, the underside of the bar with an uneven surface
5. consistency must be hard, the structure must be homogeneous, the fracture must be dull, for porous chocolate - cellular
6. additions, introduced not in a finely ground form, are evenly distributed in the chocolate mass.

Chemical composition of chocolate and cocoa beans

The shell of cocoa beans is not used in the manufacture of chocolate, although sometimes this is the case. Cocoa shell contains in large quantities: mineral compounds, aromatic oils, ash 10%, fiber up to 15%, fat 3-5%, pentosans about 6%, pectin 4.8% in a fat-free substance.

Cocoa butter contains: triglycerides of saturated fatty acids - palmitic, oleic, stearic, theobromine and caffeine alkaloids, antioxidants (do not allow to burn and salt), aromatic and tannins, which actually gives the taste and aroma to chocolate. The aromatic bouquet of chocolate is also formed due to the gradation of cocoa beans into noble and consumer. The first give chocolate a bright taste and aroma, the second - bitterness, astringency, acidity. Cocoa butter has seven polymorphic forms, one of which is very stable and allows chocolate to be stored for a long time. The secret is that at room temperature, cocoa butter solidifies on its own, but melts in your mouth. Therefore, real chocolate should not contain any hardeners.

The average composition of cocoa beans is shown in table No. 1.

substances	composition in %
Fat	45-50 %
nitrogenous substances	13-16 %
Cellulose	3-9 %
Starch	5-10 %
Tannins (tannin) and colorants	5-7 %
Theobromine	1-2,4 %
Pentosans	1-2 %
Essential oil	0,001 %
Organic acids (malic, citric, oxalic)	up to 2%
Water	6-9 %
Ash	2,5-5 %
Caffeine	40 %
saccharides
Squirrels	11,5 %
Other minerals and salts	2,6 %

Chocolate classification

Depending on the method of processing, the chocolate mass is divided into dessert and ordinary.Dessert chocolate masshas high aromatic qualities and finedispersion. It acquires these properties as a result of particularly careful and lengthy processing. ContentSaharain it no more than 55%.Ordinary chocolate masshas lower taste and aromatic qualities and less fine dispersion. The sugar content in it is not more than 63%. Aerated chocolate is obtained mainly from the dessert chocolate mass, which is poured into molds for ¾ of the volume, placed invacuum- boilers and kept in a liquid state (at a temperature of 40 ° C) for 4 hours. When the vacuum is removed, due to the expansion of air bubbles, a finely porous structure of the tile is formed (“Humpbacked Horse”, “Glory”, “Planet”, “Congratulations”, Wispa, Schgetten, Sonnina). Depending on the composition, chocolate is divided into chocolate without additives, with additives, with filling, diabetic and white.Chocolate without additivesmade from cocoa mass, powdered sugar and cocoa butter. Such chocolate has specific properties inherent in cocoa beans. By changing the ratio between powdered sugar and cocoa mass, you can change the taste of the resulting chocolate - from bitter to sweet. The more cocoa liquor in chocolate, the more bitter taste and brighter aroma chocolate has and the more it is valued.Chocolate with additionsare made from cocoa mass, cocoa butter, powdered sugar and various nutritious, flavoring and aromatic substances. As additives, drymilk, dry cream, kernels nuts, coffee, waffles, candied fruit, alcohol, cognac, vanillin, food essences and more. The ratio between the listed components of chocolate reflect the characteristics of its assortment, and varies widely.Chocolate with fillingprepared from chocolate mass without additions and with the addition of milk. They produce it in the form of tiles, long loaves, shells and other figures with various fillings: walnut, fondant, chocolate, fruit-jelly, cream, milk, creamy. The amount of filling should be no more than 50% of the total mass of products (Assortid, Coconut).Chocolate diabeticintended for patientsdiabetes. The composition of chocolate instead of sugar is introducedsorbitol, xylitol, mannitol.

Chocolate white prepared according to a special recipe from cocoa butter, sugar, milk powder, vanillin without adding cocoa mass, so it has a cream color (white) and does not containtheobromine("Khreshchatyk", "Children's", "Air" and others). Depending on the form, chocolate is produced in the form of bars, figures and powder. Chocolate figures are made from dessert chocolate mass in the form of various hollow objects and animal figures. Powdered chocolate is produced from cocoa mass and powdered sugar without additions and with the addition of dairy products (Suflair, Karina, Schogetten).

The history of chocolate

Chocolate - the history of invention

Chocolate used to be considered a treat for children. If we fast forward about three thousand years, then the popular belief would certainly be refuted. Chocolate For a long time it was exclusively a drink. It was consumed cold - roasted cocoa beans, which themselves have a bitter taste, were mixed with water, and then chili peppers were added to this mixture. The ancient civilization of mistletoe, which happened to be the first to taste the invented drink, gave the name that is still used today. They said "kakawa". It is surprising that for such a long time only a few letters have changed in the name. Contrary to the name, the composition of chocolate has undergone significant changes since then, but the path to this has been a long one. Around the same time, namely three thousand years ago, another delicacy was invented, which is now inextricably linked with chocolate. The ancient Egyptians accidentally mixed honey, figs and nuts - and became the owners of the very first candy in the world.

Cocoa beans instead of coins.

By 600 AD, chocolate had not lost a single component of its original composition. The history of the development of chocolate was continued by the Mayan tribe. During this period, paganism caused chocolate to become a highly prized drink, with many religious rituals and traditions associated with it. The value of chocolate was great, because it was equated with the food of the gods. The Maya Indians at that time lived in Central America, on the Yucatan Peninsula. Now in this territory is Mexico, in which chocolate is currently familiar, but no less important. During the time of the Mayan Indians, cocoa trees were deliberately not grown. There were a lot of them, but not enough for everyone to drink the divine drink to their heart's content. As a result, the Indians began to use cocoa beans as a means of payment. Each fruit counted: for 100 cocoa beans, for example, you could buy a slave. When the calculations were carried out in considerable amounts, the fruits were considered not by the piece, but by pods, each of which weighs about 500 g, and for the purpose of profit, the ancient "counterfeiters" took cocoa beans out of the pods and filled them with something less valuable. Later, the impracticality and value of cocoa fruits prompted the Mayans to start building cocoa plantations - as you know, there should be a lot of good ones.

A gift from the Aztecs.

The Aztecs of Central America had a much easier time with respect to cocoa. The Indians who lived in their territory earlier erected plantations, and the harvest from year to year became more and more. The value of the fruit of the tree declined slightly, and cocoa beans began to be used as a tribute. This was the period of the first long-distance voyages and discoveries, a step towards making chocolate famous in Europe. So, in 1517, the Spaniard Hernan Cortes arrives in Mexico. The Aztecs take him for the returned god Quetzalcoatl. But Cortes' plans also turned out to be grandiose: he conquered Mexico. And yet - he realized that the “chocolatl” would help him win an excellent position in his homeland. Cortez was right. The ships that were loaded with cocoa beans and devices for the production of cocoa were a real discovery for Spain. The Spaniards were in no hurry to distribute chocolate outside the country, the supply volumes did not allow it. In addition, they kept the recipe for the preparation of the drink a secret. What the Spaniards did with cocoa beans is already closer to the chocolate that we know. The new recipe included cinnamon, nutmeg and sugar. Chili peppers were bypassed, and the drink was now served hot. These changes turned out to be beneficial for chocolate.

Chocolate storage

Store chocolate at 18 0 C and relative air humidity 75%. Under these conditions, chocolate is stored for the following warranty periods from the date of production:

1. dessert and ordinary without additions - 6 months,
2. weight without additives unwrapped - 4 months,
3. dessert and ordinary with additions, chocolate with filling and in powder without additions - 3 months,
4. by weight with additions, unwrapped - 2 months,
5. white chocolate and powder with the addition of dairy products - 1 month.

In order to avoid graying of the chocolate, sudden temperature fluctuations are not allowed. When heated (temperature above 20 0 C) fat bloom of chocolate occurs - it is covered with a gray coating. It is the fats contained in chocolate that show through on its surface. At temperatures below 18 0 With sugar blooming of chocolate occurs, caused by the condensation of water vapor and the partial dissolution of the sucrose contained in chocolate. After evaporation of moisture, sucrose crystals form a white coating on the surface of the chocolate.

experimental part

Research objects:

1. Dark chocolate "Russian"

Manufacturer : OAO Confectionery Association of Russia

Compound : Sugar, cocoa mass, crushed almonds, cocoa butter, stabilizer (milk fat), alcohol, emulsifier, soy lecithin E476, salt, flavor identical to natural (rum).

1. Milk chocolate "Alenka"

Manufacturer : OAO Krasny Oktyabr

Compound : Sugar, whole milk powder, cocoa butter, cocoa mass, emulsifiers: E476 lecithin, vanilla flavor identical to natural.

1. White chocolate "Porous"

Manufacturer : CJSC Russian Chocolate Factory

Compound : Sugar, cocoa butter, whole milk powder, lactose, whey powder, emulsifiers: E322, E476, vanilla flavor

Table #1

chocolate name	squirrels	fats	carbohydrates	the nutritional value
Dark "Russian"	6.6 g	32.6 g	52.1 g	529 kcal
Lactic "Alenka"	8.2 g	33.3 g	53.5 g	538 kcal
White "Porous"	6.5 g	33.4 g	56.5 g	547 kcal

Experience number 1. Determination of the quality of "chocolate bar".

(According to GOST, the composition of the “chocolate bar” should include only crushed cocoa beans, cocoa bean butter. When vegetable fats and soy are added to these products, the final product should be called “sweet bar”. “White chocolate” contains a small amount of cocoa butter, the basis of this chocolate is condensed milk.

To conduct the experiment, samples of chocolate bars of different brands weighing 5 g are taken, placed in different test tubes and heated in a water bath until the end of melting. The thermometer determines the melting point of the sample. The measurement results are entered in the table (Table No. 2). With an increase in the proportion of vegetable fats in the composition of chocolate, and consequently, the chemical composition of chocolate, the melting point of chocolate decreases.

Table number 2

Conclusion: The lower the melting point, the more vegetable fat and less cocoa butter. The best composition of chocolate "Alenka".

Experience number 2. Determination of the presence of foreign impurities in chocolate.

Pour a small amount of hot water into a flat-bottomed flask and lower a piece of chocolate sample weighing 5 g, put the flask in a water bath. After waiting for the chocolate to completely dissolve, and after cooling the contents of the flask, add a few drops of an alcoholic solution of iodine to the contents of the flask. If chocolate is mixed with farinaceous or starchy substances, then the broth will turn bluish; a decoction of pure unadulterated chocolate under the influence of the same reagent turns slightly greenish. Data for all samples of chocolate products are entered in the table (Table No. 3).

Table #3

Experience number 3. Detection of unsaturated fats in chocolate(cocoa butter).

A piece of chocolate must be wrapped with filter paper and pressed on it so that grease spots appear on the filter paper. A drop of 0.5 M solution of potassium permanganate KMnO is placed on the fat spot. 4 and is formed, due to the occurrence of a redox reaction, a brown precipitate of manganese (IV) oxide - MnO 2 .

Conclusion: Unsaturated fats found in chocolate "Alenka" and dark "Russian"

Conclusion: Three bright colored rings are expressed in white chocolate. Carbohydrates are everywhere.

Experience number 6. Detection of proteins in chocolate (xantoprotein reaction).

Pour grated chocolate (about 1 cm in height) into a test tube and add 2 ml of distilled water. Shake the contents of the tube well several times and filter. To 1 ml of the resulting filtrate is added 0.5 ml of concentrated nitric acid HNO 3 and heat the resulting mixture. A yellow color is observed, turning to orange-yellow when 25% aqueous ammonia is added. Such a reaction is given by the residues of aromatic amino acids that make up chocolate proteins.

Conclusion : All samples contain proteins. Most of all in dark chocolate "Russian"

I enter the data of experiments No. 3-6 in the table (Table No. 4).

Table No. 4

Experience	Dark chocolate	Milk chocolate	White aerated chocolate
detection of unsaturated fats	Discovered	discovered	not detected
carbohydrate detection	present	present	3 rings are pronounced
protein detection	More protein content	present	present

The effect of chocolate on the body

Already the rich chemical composition of chocolate speaks of the value of this product. That's where the benefits of chocolate lie.

1. Chocolate activates the production of endorphins, hormones of happiness, improves tone and mood, efficiency and ability to concentrate. The reason is theobromine, it excites the central nervous system, invigorates and relieves headaches. Serotonin, phenylethylamine and tryptophan are excellent antidepressants. Magnesium resists depression, stress, improves memory, has a beneficial effect on immunity, and circulates cellular metabolism.
2. Bitter chocolate reduces blood pressure and promotes increased absorption of sugar.
3. The alkaloid caffeine belongs to psychostimulants, activates the activity of the cardiovascular, nervous and respiratory systems. It invigorates, increases mental and physical activity, removes vascular headache, fights children's enuresis.
4. Magnesium and potassium are essential for the central nervous system and muscles; phosphorus for brain activity, calcium is needed for bones, fluorine for teeth.
5. Antioxidants (polyphenols, catechins, flavonoids) stop aging and normalize heart activity by fighting free radicals. All flavonoids contribute to the regulation of processes in the skin, keeping it young for a long time. Kokokhil is fraught with wound-healing, wrinkle-smoothing, renewing skin cells action.
6. Sweet aspirin - chocolate - helps to thin the blood. Reduces headache and sore throat. Cocoa flavonoids improve metabolic functions and prevent the formation and deposition of cholesterol in blood vessels, and their damage.
7. The antibacterial action of chocolate theanine prevents the formation of plaque, thereby fighting caries.
8. Theobromine and theophylline activate the biochemistry of the skin, providing lifting.
9. Chocolate caffeine is a leader in the fight against excess weight and cellulite, it normalizes lymph flow and blood flow, relieves swelling, activates the breakdown and elimination of negatively acting fats, toxins and toxins.

However, chocolate does have its downsides. The tannin contained in chocolate can cause headaches in people with poor blood vessels, and an excess of chocolate at night can cause untimely vigor and sleep deprivation. Eating a lot of chocolate can not only cause allergies, but also greatly increase the heart rate. Chocolate is a high-calorie food and its excessive consumption can cause weight gain.

Sociological survey

The survey involved 21 students of grade 10.

Application of chocolate

Currently, chocolate and its products are used in various fields of activity. Cocoa seed powder, as we know, is used to make cocoa drink and chocolate. Cocoa seed oil, in addition, is used in food production, is used in medicine to obtain the basis of suppositories (candles). The husks of cocoa beans (seeds) are used in the manufacture of toothpaste. It contains an antibacterial substance that “fights” plaque on the teeth. Just a few years ago, such super-fashionable procedures as chocolate wraps, chocolate baths, chocolate masks appeared in Russia - and it seems that this is a panacea for old age. The use of chocolate in cosmetic procedures in beauty salons and even at home on your own allows you to always remain young and beautiful.

With the help of chocolate procedures, you can:

1. get rid of cellulite
2. make a face, neck, décolleté lift
3. restore the elasticity of the skin of any problematic part of the body
4. lose weight
5. experience the relaxing effect of a chocolate bath
6. moisturize your face
7. cheer up (aromatherapy)
8. get rid of postpartum stretch marks and venous asterisks
9. get rid of "young" keloid scars.

Work Conclusions

In the course of the work, samples of chocolate that are in demand among the population were studied:Dark chocolate "Russian", Milk chocolate "Alenka", White chocolate "Porous".Real chocolate is a confectionery product, in the manufacture of which only cocoa butter and cocoa mass are used (a mixture of grains of cocoa beans in cocoa butter), and not a product based on cocoa powder and cocoa butter substitutes based on vegetable fats.Studied chocolate product (not adulterated or adulterated) by-products. The highest content of unsaturated fats was observed in milk chocolate "Alenka" and in dark "Russian", the qualitative reaction to carbohydrates was most clearly manifested in white "Porous" chocolate.

The most useful is Alenka milk chocolate without fillings and additives, containing a maximum of cocoa products. Chocolate is not harmful to health if consumed in moderation!

Appendix

Recipes of modern cosmetology

Chocolate masks

Chocolate mask is a mixture of chocolate powder, which includes natural extracts of plants and fruits, seaweed, clay and other active ingredients, and warm water, and cocoa butter, when mixed, it forms a plastic consistency. This mask is applied to the previously cleansed skin of the body - with the hands, and on the face (avoiding the area around the eyes), neck, décolleté with a brush. After 15-20 minutes, the mask is washed off with warm water and removed with wet wipes. The final stage is the application of cream, serum, corresponding to the type of skin and care program.

For dry skin . In this case, we need white chocolate and yogurt. Melt 2 tablespoons of chocolate in a water bath. In liquid chocolate, add 1 tablespoon of yogurt (without fruit additives with the highest% fat content). Mix the resulting mixture with a mixer and apply on the face for 15 minutes. The result is soft, hydrated and fragrant skin.

For normal and combination skin. We will use a dark chocolate mask. Melt 2 tablespoons of dark chocolate in a water bath, then add 1 teaspoon of olive oil. After cooling the mixture to room temperature for 10 minutes, apply it on the face and then rinse with warm water. The mask nourishes and tightens the skin, gives it freshness and golden color.

Any of these masks will bring unearthly pleasure, cheer up and improve skin condition.

Mask for dull and sparse hair. Mix 2 tablespoons of cocoa butter with a teaspoon of cognac. Apply the mask on the scalp and hair roots, massage lightly. Leave on for 10-15 minutes, rinse with shampoo. Such a mask is done once or twice a week and stimulates the blood circulation of the scalp, nourishes the hair, helps to supply them with the necessary vitamins and oxygen.

Bibliography

1. A book about tasty and healthy food. - Moscow "Food industry" 1963
2. Pruzhnikov I. I. "A Cup of Chocolate" - Moscow "Food Industry" 1997
3. Bogdanov A. K. - "Chocolate in the Russian tradition" Moscow "Essays" 1996
4. Vorobyov V.I. - Moscow "The components of health" "Knowledge" 1987
5. Skurikhin I. M., Nechaev A. P. - Moscow "Everything about food from the point of view of a chemist" "High School" 1991
6. Fremantle M. - Moscow "Chemistry in action" "Enlightenment" 1990
7. Internet site: www.samcond.ru

For oily skin . We will use a dark chocolate mask. Mix 1 tablespoon of melted dark chocolate with 1 tablespoon of fruit and berry puree. For puree, we need an apple, red currant (you can use cherries and cranberries). All this is “refueled” with 1 teaspoon of lemon juice. We put the finished mask on the face for 10 minutes and rinse with warm water.

Experience number 4.

Pour grated chocolate into a test tube and add 2 ml of distilled water. Shake the contents of the tube well several times and filter. To the filtrate add 1 ml of 2M sodium hydroxide solution NaOH and 2-3 drops of 10% solution of copper sulfate (II) CuSO 4 , shake the tube vigorously. A bright blue color appears. This reaction gives sucrose, which is a polyhydric alcohol.

Conclusion: Most of the sucrose in the white "Porous", and the least in the dark "Russian"

Experience No. 5

Detection of carbohydrates in chocolate

(color Molisch reaction).

Pour grated chocolate (about 1 cm in height) into a test tube and add 2 ml of distilled water. Shake the contents of the tube well several times and filter. To the filtrate add 1-3 drops of an alcohol solution of resorcinol or thymol. Tilt the tube and carefully pour 1-2 ml of concentrated sulfuric acid H 2 SO 4 . We fix the test tube in a vertical position. Heavy acid will sink to the bottom, and a bright beautiful ring will appear on its border with water - red, pink or purple.

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INTRODUCTION

The topic of my research work is “Chocolate Analysis”

Chocolate is a delicacy known all over the world. As is known from the historical annals, chocolate was eaten only by rich people. And today it is the most popular delicacy. However, doctors, nutritionists, scientists argue that chocolate has a positive effect on the human body, other experts argue the opposite, that chocolate is harmful to health. There are stable ideas: chocolate is a “cure” for depression and a remedy for fatigue, and chocolate is also able to activate the mental activity of the brain.

Opponents of sweet treats say: you can gain weight, is addictive, and is bad for your teeth.

Where is the truth and where is the lie? Is chocolate good or bad? After asking myself these questions, I became interested in learning as much as possible about chocolate. And most importantly - what kind of chocolate is the most useful? What real chocolate is made of, I tried to find out in my research work.

Hypothesis: I assume that the chocolate we buy in the store is good for us.

Target: Find out if chocolate is good for our body. Is it possible to eat chocolate all your life. The study of the composition of chocolate of different brands and the study of its effect on human health.

Tasks:

Get to know different types of chocolate.

Conduct a survey among students about chocolate.

To study the effect of chocolate on human health.

CHAPTER 1. LITERATURE REVIEW 1.1 History of creation

Chocolate in Latin means "food of the gods". Black, milky, white, porous - all this is said about the favorite delicacy of adults and children - chocolate. Chocolate is native to Central and South America.

There are a lot of stories and legends connected with the appearance of chocolate. It is generally accepted that the Maya Indians, who lived on the shores of the Gulf of Mexico, were the first to discover the secret of the taste of chocolate and considered cocoa beans to be divine fruits, to which all sorts of beneficial, and sometimes mystical properties were attributed.

Christopher Columbus, who tasted it in 1502, is considered the first European who got acquainted with a chocolate drink. Neither the navigator himself nor his associates appreciated the taste of the drink: the Indians prepared it, flavoring it with hot pepper and fermented cactus juice. But everyone noted the high price of cocoa.

17 years after the return of Columbus, the conqueror of Mexico, Hernan Cortes, brought an Aztec recipe for a chocolate drink to the Spanish court.

Replacing pepper and cactus mash with sugar and milk in the traditional Indian drink, the Spanish nobility appreciated chocolate highly in every sense. “He who drinks cocoa drinks money,” wrote the historian Gonzalo Fernández de Oviedoi-Valdes at the time.

The King of Spain and his entire family have become loyal fans of the invigorating drink. From them, the fashion for chocolate quickly spread among the Spanish aristocrats. Curiously, today the Spaniards are the most inactive chocolate consumers in Europe. There is no trace left of the old traditions.

In the next 100 years, chocolate from Spain, despite the measures taken to prevent its distribution, penetrated all European capitals, eclipsing other overseas products in price and popularity.

In the 17th century, chocolate also penetrated Russia. But who exactly veils this delicacy is not known. Only information remained in the memoirs about the use of chocolate, in 1882 the court orchestra, Colonel Baron K.K. Stackelberg wrote: "... at the Imperial Court, after a meal, in addition to coffee, a cup of chocolate was served - a custom that has been preserved since the time of Empress Elizabeth."

In the XVIII century. chocolate was credited with the ability to cure fever, catarrh of the stomach and even prolong life. At that time, the price of chocolate was so high that not all classes could afford it. In the 19th century the number of cocoa plantations in the world has increased significantly, and the price of beans has dropped significantly. As a result, chocolate became a completely affordable drink - until the 19th century it was consumed only in liquid form.

It took another two centuries for chocolate to acquire its modern shape, taste, and affordability. The first tiles, which appeared thanks to the English company Fry and Sons, were immediately appreciated. And in 1876, Daniel Peter invented a new kind of chocolate - milk chocolate. At the beginning of the XX century. Nestlé starts producing milk chocolate according to the recipes of Peter and Kohler, two of the most famous experts in the field.

Simultaneously with the European ones, the most famous Russian chocolate companies were founded. Now they are called "Concern Babaevsky", "Red October", "Rot Front". It was in Russia that they were the first to add liqueurs, cognac, almonds, raisins or candied fruits to chocolate.

The history of chocolate goes back many centuries. Chocolate has come a long way before appearing in Russia. At first it was a delicacy only for the rich nobility, now it is a public pleasure for everyone.

1.2. Chocolate composition

The main raw material for its production is cocoa beans, the seeds of a cocoa tree that grows in tropical regions. This is exactly what the composition of the very “bitter” chocolate looks like, which is considered something exclusive and which is so hard to buy today in ordinary confectionery stores.

Chocolate is made from cocoa products. Cocoa fruits contain an average of 35 - 50% oil, called cocoa butter or theobromine oil, 1-4% theobromine, 0.2-0.5% caffeine, tannins and other substances. Cocoa butter consists of glycerides of oleic (approximately 35%), stearic (35%), palmitic (26%) and linoleic (3%) acids. In chocolate, the content of caffeine and theobromine alkaloids can reach 1-1.5% (theobromine - up to 0.4%). They are natural stimulants, which explains the tonic effect of chocolate on the human body.

Dark chocolate, which is very hard in texture, has a rather unique composition indeed. You need to start with the fact that it has a lot of fat. He owes this to cocoa butter. 100 grams of good dark chocolate contains almost 25 grams of fat. And about 400 kilocalories. By the way, in the composition of milk chocolate, the ratios are about the same. Only a part of vegetable fats are replaced with animal fats - from milk powder and cream.

Theobromine, a nitrogenous substance found in chocolate, is a terrible poison for many animals. For example, 3-4 grams of theobromine is enough to kill a large dog.

But for humans, this substance does not pose a threat, since our body quickly digests it. But theobromine itself has the properties of alkaloids, due to which it affects the psyche in a certain way.

Chocolate is sensitive to fluctuations in temperature, so it must be stored at a temperature of about 15 0 C. When heated, fat blooming of chocolate occurs - it becomes covered with a gray coating: the fats contained in it appear on the surface. At temperatures below 18 0 C, sugar blooming of chocolate occurs, caused by the condensation of water vapor and the partial dissolution of the sucrose contained in chocolate. After evaporation of moisture, sucrose crystals form a white coating on the surface of the chocolate. The graying of chocolate products does not lead to the formation of substances harmful to health, but only spoils the presentation of chocolate.

Conclusion: chocolate is practically a neutral product. It can be consumed with both fats and carbohydrates. And therefore, today everything that the soul of a confectioner can wish for is added to the composition of chocolate.

1.3. Chocolate classification

Chocolate is a confectionery product made using cocoa fruits, one of the most common confectionery products.

bitter (more than 60%);

semi bitter (about 50%);

dairy (about 30%);

White chocolate does not have a characteristic chocolate color, since it does not contain cocoa liquor, but has a white color with a yellowish tint. More than 20% of milk powder is introduced into such chocolate, and only cocoa butter is used as a cocoa product.

II. Depending on the recipe and processing method, chocolate is divided into:

ordinary;

dessert;

porous;

with stuffing.

Chocolate without additives is a product made from cocoa mass, cocoa butter and sugar. are called natural.

The composition is distinguished:

Lactic;

White; diabetic;

Powdered chocolate.

According to the technology of preparation - porous.

Dark chocolate is the most expensive type of chocolate. The more cocoa it contains, the more expensive and valuable the tile of such a delicacy. This is the very first type of solid chocolate. It is the basis of all other species. It contains nothing superfluous, only grated and roasted cocoa beans, cocoa butter and powdered sugar.

White chocolate. This type of sweets is not chocolate, because it does not contain cocoa beans. It is a mixture of cocoa butter, vanillin and milk powder, to which various flavors are added.

Milk chocolate. The composition of this type contains milk or dry cream, which are responsible for the tenderness of the taste of this product, and cocoa beans provide its wonderful aroma.

1.4. The effect of chocolate on the human body

In all products made from the seeds of the chocolate tree, there are biologically active substances of various composition, but small in quantity, which have a number of medically useful properties.

Pros of chocolate:

Feeling better.

Caffeine and theobromine are found in chocolate. In small doses, they have an exciting effect on the nervous and cardiovascular systems.

Typically, chocolate contains 0.4% theobromine. This amount is completely safe. The removal of fatigue, the return of vivacity is the effect of theobromine on a person. For some people, eating chocolate, on the contrary, has a calming effect.

Eating 45 g of chocolate per day, you will save yourself from a heart attack. Swedish scientists have proven that people who often consume chocolate are less prone to heart attacks. Its regular use reduces the risk of vascular disease by approximately 25%.

Chocolate contains magnesium, which has a beneficial effect on brain activity.

Gives energy.

Reduces the level of cholesterol in the blood.

Good for the heart and blood vessels.

Normalizes pressure.

It has a beneficial effect on the skin (chocolate masks).

Strengthens bone tissue.

Cons of chocolate:

In addition to all the useful properties of this confectionery masterpiece, it also has harmful properties. Those who claim that the harm from chocolate is much more than the benefits are completely wrong. But excessive consumption of chocolate is not always healthy:

leads to dependence, which leads to an unbalanced psycho-emotional state.

can lead to diabetes.

oxalic acid contained in the delicacy interferes with the absorption of calcium and is therefore dangerous for people suffering from urolithiasis.

CHAPTER 2. RESEARCH WORK 2.1 Questioning.

A survey was conducted with the participation of 35 students from grades 8-11.

Purpose: Find out what brand of chocolate is most consumed.

1 question:

Conclusion: From the chart above, we can see that 97% of those surveyed say they have consumed chocolate and only 2.8% say they do not.

2 question:

Conclusion: From the results of this survey, we see that more than half of the respondents consume chocolate once a week. 14% of respondents consume chocolate once a month, and 29% every day.

3 question:

Conclusion: From the chart above, we can conclude that almost half of the respondents prefer Alpen Gold brand chocolate, they make up 49%. 31% of respondents prefer milka brand chocolate, 23% prefer dove. The rest of the respondents prefer chocolate "Alenka", "Babaevsky", "Korkunov", "Kitkat", their percentage ranges from 3-9%.

4 question

Conclusion: from the above diagram, we can conclude that the most useful chocolate according to the respondents is "Dove" (10 points). Benefits of Kitkat chocolate were rated at 9 points; 8 points - "Korkunov"; 7 points - "Babaevsky"; chocolate brand "Alenka" was rated 6 points; 5 points Milka.

2.1 EXPERIMENTAL STUDY OF CHOCOLATE

Experience 1. detection of carbohydrates.

Place grated chocolate in a test tube 1 cm high and add 2 - 3 mo of water to it. Shake the contents of the tube vigorously for 1 minute, then filter it. Divide the filtrate into two tubes. Then add to the first 2-3 ml of sodium hydroxide solution and 3-5 drops of copper sulphate solution. Shake the contents of the tube and observe the formation of a bright blue solution. This indicates the presence of polyhydric alcohols in the composition of chocolate.

Result: Carbohydrates are contained in all samples.

Experience 2. Protein detection.

Add 0.5 ml of concentrated nitric acid to the filtrate in the second tube. Heat the mixture. Observe a yellow precipitate that turns orange when ammonia solution is added to it. This is a well-known qualitative reaction to proteins - xantoprotein.

Result: The presence of yellow color indicates the presence of caffeine, the presence of proteins.

Experience 3.

Chocolate should be refrigerated for 1-2 weeks. Then lay out for a few minutes and put on the battery.

Result: With a sharp change in temperature, cocoa butter appears on Milka chocolate - chocolate “turns gray”, and AlpenGold chocolate does not “turn gray”, which means that this chocolate does not contain cocoa butter.

Experience 3. Fat detection.

Fat in chocolate is easy to detect by the greasy stain that leaves a piece of chocolate on filtered paper under pressure. If a 0.5% solution of potassium permanganate is dropped onto such a spot, it turns brown due to the resulting manganese (IV) oxide. The residues of unsaturated acids that make up chocolate are oxidized by potassium permanganate at the double bond site to form two hydroxy groups.

Result: Fats are plentiful. AlpenGold has more unsaturated fats, which indicates the replacement of cocoa butter, vegetable or milk fat.

CONCLUSION

In the course of the work, samples of milk chocolate were investigated: "Milka" and "AlpenGold". Real chocolate is a confectionery product, in the manufacture of which only cocoa butter and cocoa mass are used, and not a product based on cocoa powder and cocoa butter substitutes based on vegetable fats.

In terms of quality, milk chocolate showed itself best - Milka, Alpen Gold, but, more precisely, on a scale from 1 to 10, Alpen Gold showed itself best, since this chocolate contains whole milk powder.

According to the results of the survey, the indicators also confirmed that the most useful and delicious is Alpen Gold milk chocolate without fillings and additives, with a maximum content of cocoa products.

After studying chocolate, we came to the conclusion that it means that chocolate is not harmful to health if consumed in moderation.

BIBLIOGRAPHY

1. www.invitro.ru

2. www.cyberleninka.ru

3. www.roskachestvo.gov.ru

4. www.nsportal.ru

5. www.manorama.ru

7. Mendeleev D. I., Borman Zh., - chocolate // Encyclopedic Dictionary of Brockhaus and Efron in 86 volumes (82 volumes and 4 additional). - SPO., 1890-1907.

8. Chemistry at school. // Educational-methodical journal for teachers of chemistry. - №2 2013. p.18

Annex 1. Questionnaire.

1. Do you eat chocolate?

A) Yes; B) No

2. How often do you eat chocolate?

A) Every day B) 1 per week; B) once a month

3. What brand of chocolate do you prefer?

4. How would you rate the health benefits of your favorite chocolate on a scale of 1 to 10?

Appendix 2

Experience 1. detection of carbohydrates.

Experience 2. Protein detection.

Experience 3. Content of cocoa butter in chocolate.

Experience 4. Fat detection.

Kostousova Daria

The problem of this study is to determine the chemical composition of chocolate, as well as to identify the reasons for the "graying" of chocolate during storage.

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Magdagachinsk municipal secondary school No. 3

Chocolate research

Completed by: Daria KOSTOUSOVA, student of grade 5 B of Moscow School of Education No. 3

Supervisor

Puzyreva Marina Dmitrievna,

chemistry teacher, MSOS № 3

Magdagachi, 2008.

1. Introduction……………………………………………………………3

1. Research problem……………………………………3
2. Object of study……………………………………….4
3. Subject of research……………………………………...4
4. The purpose of the study………………………………………….4
5. Research objectives………………………………………..4
6. Research hypothesis……………………………………..4
7. Research methods………………………………………4
8. Stages of preparation and conduct of the study…………..4
9. Work Plan………………………………………………………5

1. The content of the work………………………………………………..5

1. Conducting research………………………………….5
2. Research results…………………………………..6

1. Conclusions……………………………………………………………..6
2. Literature………………………………………………………….7
3. Application………………………………………………………...8

Introduction.

Chocolate is a mixture based on cocoa powder with the addition of sugar, cocoa butter, skimmed milk powder, and some other components. It is one of the most popular products in the world. Here are just a few numbers to prove it:

The country	The amount of chocolate, kg per year per person
Switzerland
Germany
France
USA
Russia

The botanical name of the chocolate tree translates as "food of the gods". The name chocolate comes from the Indian "choco-latl" - "morning drink of the Aztec leader."Europe learned about the chocolate drink only in the 16th century, when the Indians offered Christopher Columbus a bowl of chocolate as a gift. He, however, did not appreciate the gift. But Columbus' colleague Hernando Cortes liked the outlandish delicacy. He brought the recipe of the Indians to Spain. The fashion for "chocolate", which began to add cane sugar, has spread swiftly.

The result of long studies has shown that the substances contained in chocolate do not harm human health at all. Conversely, frequent consumption of chocolate reduces the likelihood of cancer, stomach ulcers, hay fever and strengthens the body's immune system. Moreover, each piece of chocolate eaten increases a person's resistance to stress, and the cocoa contained in chocolate saves our teeth from destruction, enveloping the enamel with a thin protective film. Researchers note that the substances that make up chocolate prevent the growth of bacteria, and therefore protect teeth from caries.

Cocoa butter itself contains stearic acid, which helps lower blood cholesterol levels. Chocolate consumed in moderation - about two bars a week - supports the cardiovascular system. The European Society of Cardiology recently confirmed that the polyphenols contained in cocoa beans help increase blood flow, thus partially reducing the workload on the heart.
High quality dark chocolate has a positive effect on the immune system. Some varieties of chocolate contain vitamins A and B, iron, calcium and potassium more than an apple, a glass of yogurt and a slice of cheese. Chocolate is rich in magnesium, which boosts your mood.

That is why I was so interested in this topic - what is there, in my favorite delicacy? In addition, sometimes when buying chocolate, some kind of coating on the bar will be noticed. What's this? And what contributes to the appearance of this plaque? I tried to find answers to these questions.

The problem of this study

The problem of this study is to determine the chemical composition of chocolate, as well as to identify the reasons for the "graying" of chocolate during storage.

Object of study.

The object of the study is chocolate "Babaevsky".

Subject of study.

The subject of the study is a method for determining carbohydrates, proteins, caffeine and cocoa butter in chocolate, as well as substances that cause "graying" of chocolate.

Purpose of the study.

1. Determine the presence of carbohydrates, proteins, fats in chocolate, find out the reason for the “graying” of chocolate during storage.

Tasks:

1. Carry out a study of chocolate for the detection of carbohydrates;
2. conduct a study of chocolate for the detection of fats;
3. conduct a study of chocolate for the detection of proteins;
4. to lay an experiment, simulating the conditions of "graying" of chocolate (storage in various conditions - at low and high temperatures);
5. examine the substances formed during storage on the surface of the chocolate.

Research hypothesis.

The research hypothesis is that when chocolate is stored, fats (fat bloom) and sucrose (sugar bloom) are released on its surface.

Research methods:

1. analysis of theoretical material;
2. sociological survey;
3. rating;
4. chemical experiment;
5. modeling conditions;
6. observation;
7. establishing a causal relationship;
8. generalization.

Stages of preparation and conduct of the study.

1. At the first stage of researchstudied special literature on the study of confectionery, the properties of chocolate, the chemical composition of chocolate. Practical techniques were practiced, various methods of working with laboratory equipment, various reagents were selected, theoretical studies were carried out on this issue in order to determine the problems and justify the use of various methods. The first stage included a learning study.
2. At the second stage of the study, an experiment was conducted to study the chemical composition of chocolate.
3. At the third stage of the study, a chemical experiment was laid to simulate the storage conditions of chocolate at low and high temperatures and studies of substances that cause chocolate "graying" were carried out.

Work plan.

1. The study of literature on the study of confectionery, the properties of chocolate, the chemical composition of chocolate.
2. Formulation of the problem.
3. Definition of the object and subject of research.
4. Goal definition.
5. Definition of tasks.
6. Formation of a hypothesis.
7. The choice of research methods.
8. Definition of research stages.
9. Conducting an experiment.
10. Systematization of research results.
11. Analysis of the results and generalization of the findings of the study.
12. Formulation of research work.
13. Presentation preparation.
14. Presentation of the research work.
15. Discussion of the results of the work.

In the process of work, chocolate "Babaevsky" was investigated.

1. Detection of unsaturated fats in chocolate.

I wrapped a piece of chocolate in filter paper and pressed on it so that grease spots appeared on the paper. Place a drop of potassium permanganate solution KMnO on the stain that appears. 4 . The stain turned brown. This formed manganese (II) oxide MnO 2 . A change in color is a sign of a chemical reaction, which means that here the fat from the chocolate has reacted with potassium permanganate KMnO 4.

1. Detection of carbohydrates in chocolate.

Grated chocolate (about 1 cm in height) was poured into a test tube and 2 ml of distilled water was added. Shake and filter several times. To the filtrate was added 1 ml of sodium hydroxide solution NaOH and 2-3 drops of copper sulphate solution (copper (II) sulfate CuSO 4 ). Shake the vial several times. A bright blue color appeared. This reaction gives sucrose.

3. Detection of proteins in chocolate.

Grated chocolate (about 1 cm in height) was poured into a test tube and 2-3 ml of distilled water was added. Shake and filter several times. I added 2-3 drops of concentrated nitric acid HNO to the filtrate, being careful 3 . Heated the resulting mixture. yellow coloration was observed. I added ammonia solution, the color changed to yellow-orange. Protein substances give such a reaction.

4. Modeling the fat bloom of chocolate.

For 1 week, the test chocolate bar was kept at a temperature above 18 0 C (temperature ranged from 22 0 From to 25 0 WITH). A week later, the chocolate bar was covered with a gray coating. Carefully removed this plaque and placed in a test tube. Add 2 ml of distilled water and shake. Then I added 2-3 drops of potassium permanganate solution KMnO 4 . After shaking, the pink color of the solution turned brown.

5. Modeling the sugar bloom of chocolate.

I sprayed the chocolate bar with water, wrapped it in foil and put it in the refrigerator for 1 week (but not in the freezer compartment). A week later, a grayish-white coating appeared on the chocolate. I washed off the plaque from the chocolate with 3-4 ml of distilled water, and collected the wash in a test tube. I added 1 ml of sodium hydroxide solution NaOH and 2 drops of copper sulphate solution (copper (II) sulfate CuSO 4 ), a characteristic bright blue color appeared.

Research results.

1. Grease stain, obtained by pressing a piece of chocolate with your hand through filter paper, changed the pink color of potassium permanganate KMnO 4 to brown. Therefore, chocolate contains unsaturated fats, which are oxidized by potassium permanganate to manganese (II) oxide MnO 2 .

2. The filtrate obtained by filtering grated chocolate and water gives a bright blue color with copper(II) sulfate. This is a characteristic reaction to carbohydrates, in particular to sucrose.

3. The filtrate obtained by filtering grated chocolate and water turns yellow when concentrated nitric acid is added. The addition of ammonia solution enhances the color intensity to yellow-orange. This is a characteristic reaction to proteins.

4. Gray coating resulting from storing chocolate at a temperature of more than 18 0 C, reacts with a solution of potassium permanganate KMnO 4 . Therefore, it contains unsaturated fats, oxidized by potassium permanganate to manganese (II) oxide MnO 2 .

5. Gray-white coating resulting from storage of chocolate at temperatures below 18 0 C, gives a bright blue color with copper(II) sulfate. This is a characteristic reaction to carbohydrates, in particular to sucrose.

Conclusions:

1. The test sample of chocolate contains carbohydrates, namely sucrose.

2. The examined chocolate sample contains fat, namely unsaturated fats.

3. The examined chocolate sample contains protein substances.

4. When storing chocolate at temperatures above 18 0 With a gray coating of fat is formed on the chocolate, a fatty “graying” of chocolate occurs.

5. When storing chocolate at temperatures below 18 0 With a grayish-white coating of sucrose on the chocolate, sugar “graying” of chocolate occurs.

7. "In a difficult moment of life" to tone up and improve your mood, drink hot chocolate made from grated chocolate with cream and sugar, or allow yourself to eat a bar of dark chocolate.

Bibliography

1. Web site: http://www.nature.ru
2. Mazurkevich S. A. Encyclopedia of Delusions. Nutrition. M.: Medicine, 2006.
3. Yakovishin L.A. Chemical experiments with chocolate. Chemistry at school. No. 8, 2006