Chocolate, also known as chocolate, is a type of candy made with cocoa bean products as the main raw material. It is brown and shiny, has a delicate and smooth taste, has a special aroma, has high caloric value, is rich in nutritional value, and is easily digested and absorbed by the human body.

Fresh cocoa beans contain a lot of water and have no aroma. After roasting and fermentation, they have a strong aroma. This is formed by a variety of amino acids decomposed by fermentation. In addition, aroma components such as cream, milk powder, malt, almonds, and vanillin are added during the processing to give the chocolate a special aroma.

Chocolate candies contain high fat, high protein, high sugar content, and high calories. The melting point of cocoa butter is close to human body temperature. The cocoa beans are also rich in vitamins, trace amounts of theobromine, caffeine and other nerve-stimulating substances. The particles formed by grinding the substance many times during processing are highly emulsified and form good color, aroma and taste, making chocolate candy have high nutritional value and easy to be digested and absorbed.

There are many types of chocolate candies, which can be divided into: clear chocolate, nut chocolate, sandwich chocolate, wine-centered chocolate and nut-flavored chocolate, etc. In recent years, there has been a trend in foreign countries to develop snack-style chocolate.

The composition of chocolate candy is composed of cocoa products, sugar and dairy products. Cocoa products are products processed from cocoa beans, including cocoa liquor, cocoa butter, cocoa sugar, etc.

1. Cocoa liquor: also called cocoa or bitter material. The cocoa beans are roasted, shelled and ground into a paste shape. After cooling, they condense into a tan block solid with aroma and bitter taste, which is a semi-finished product raw material. The moisture content of the cocoa mass should be less than 4%, and the fat content should be less than 55%. Anything less than 45% does not meet the requirements.

2. Cocoa butter: It is the fat taken out from the cocoa mass, milky yellow. It is hard and brittle at room temperature. Liquid cocoa butter shrinks when cooled and becomes solid. Cocoa butter has a beautiful and unique aroma. Cocoa butter is composed of various triglycerides.

3. Cocoa powder: The cake after extracting cocoa butter from the cocoa liquor is ground into powder to become cocoa powder. The processing methods of cocoa powder are divided into general production method and alkali treatment method.

Different varieties of chocolate candies have different compositions, see the table below:

Basic composition

Milk chocolate (general)

Milk chocolate (High-grade)

Milk chocolate (for coating)

Cocoa liquor%

10～12

11～13

10～12

Cocoa butter%

22～28

22～30

22～30

Sugar%

43～55

40～45

44～48

Milk solids %

10～12

15～20

13～15

Total oil content%

30～38

32～40

35～40

Production Principle Chocolate candy has smooth, delicate characteristics and attractive aroma, which is determined by its raw materials and production process. of.

In the production process, all solid matter in the chocolate product ingredients is dispersed into extremely small particles, so that all soluble and insoluble substances are turned into very fine particles, making the chocolate very delicate and smooth. .

Secondly, the various raw materials of the chocolate products are mixed to the highest degree. After the mixing is highly homogeneous, the sugar cannot quickly precipitate and crystallize, and the oil cannot be separated, so as not to affect the seven-gram product. appearance and organizational structure.

For this purpose, various ingredients must be dispersed into extremely small particles (particle size not exceeding 80 microns) through grinding, mixing, homogenization and refining, and at the same time, various different substances must be mixed very evenly. , the tongue cannot distinguish the characteristics of different material particles, but only feels that the chocolate has become a smooth and delicate product.

In order to achieve a high degree of homogenization, emulsifiers are sometimes added to emulsify and dilute.

The aroma of chocolate is the sensory synthesis of aroma and taste. One of the main sources of its aroma is the comprehensive product of roasting and fermentation of cocoa beans. According to analysis, the aroma-producing substances of cocoa are composed of hundreds of aromatic compounds, and the special taste of cocoa comes from trace components such as theobromine, caffeine, and tannins. During the processing, the presence of sugar and milk adds to its caramel flavor. The addition of vanillin and maltol further enhances and improves the flavor characteristics of chocolate.

Viscosity is an important physical property of chocolate. Chocolate above the melting point should have good fluidity so that materials can be transported smoothly during transportation and process operations. Viscosity is particularly important in the tempering, crystallization and shaping of chocolate. Therefore, viscosity is an important technological property of chocolate. The viscosity of chocolate sauce varies at different temperatures, and the viscosity is related to the cocoa butter content.

The viscosity of chocolate is also controlled by phospholipids, moisture content, milk solids, and the particle size of dry solids.

At room temperature, chocolate products are hard and brittle. When the temperature exceeds 30°C, they will suddenly change from solid to liquid, losing their luster and complete shape. This is due to the cocoa butter. determined by its physical properties. Chocolate has a certain hardness and brittleness below its melting point, and has good fluidity above its melting point.

This duality of cocoa butter becomes apparent as it approaches its melting point. Therefore, the physical properties of chocolate candies are very sensitive when temperatures approach their melting point. This requires attention to the use of this characteristic in the mold filling, coating, packaging, storage and transportation of its production process.

Production method 1. Preparation of cocoa liquor:

(1) Roasting: After fermentation and drying of cocoa beans, the next process is roasting. The main functions of roasting are: to remove part of the water; to make the bean shell brittle and cracked, making it easier to remove the shell; to turn the dark brown cocoa beans into purple-red, allowing some of the oil to penetrate from the cells, and the bean meat becomes Bright; Roasting can change the composition of cocoa beans, starch gelatinizes into soluble particles, and aromatic substances such as acids, alcohols and esters increase; making the material plastic.

(2) Depending on the roasting method, the required temperature and time are also different. The new roasting method uses indirect hot air heat transfer for continuous roasting. Different product varieties require different roasting temperatures and times. The following are the process conditions of the hot air continuous roasting machine:

Variety

Temperature ℃

Time (minutes)

Cocoa powder

125～130

25～30

Milk chocolate

110～125

15～20

Dark chocolate

85～100

11～14

The higher the roasting temperature, the greater the loss rate of cocoa beans. It is a technical and economic indicator that needs to be paid attention to during roasting.

(2) Sieve: Although the shell of the roasted cocoa beans has cracked, the meat and shell have not been separated. They need to be slightly crushed to separate. Under mechanical impact, the beans are Broken into irregular pieces. The function of the winnowing sieve is to separate the soybean meat and skin to facilitate the processing of the soybean meat in the next process.

(3) Grinding: Grinding, also called primary grinding, is the grinding of cocoa pieces into paste. This step is very important in order to obtain cocoa liquor composed of fine particles. It is required to grind to 50-114 microns. After initial grinding, the time of the subsequent fine grinding process can be shortened and better results can be obtained. After grinding it into paste, you can get brown cocoa liquid.

There are many types of primary grinding equipment: disc mills, roller mills, tooth mills, ball mills and colloid mills, etc.

2. Fine grinding: Add a certain amount of cocoa butter, milk powder, seasonings, surfactants, spices, etc. to the cocoa liquid produced by initial grinding, processed sugar powder, etc., and then further grind it, which is called fine grinding. .

The cocoa material or sugar powder that has only been ground for the first time has larger particles and feels rough after entering the mouth. It must be finely ground to further reduce the particles.

When most of the particles of the material are finely ground to less than 25 microns or between 18 and 23 microns, the chocolate will have no grainy feel after entering the human mouth. This range is the requirement for fine grinding.

Materials undergo physical changes during the fine grinding process. As fine grinding proceeds, the material is dispersed. The finer the material is dispersed, the larger its surface area will be. The total surface contained in the total volume of a certain amount of material is called the specific surface. The larger the specific surface, the greater the number of chocolate particles, and the smaller and finer the particles.

When maintaining a certain temperature during fine grinding, the finer the grinding, the thicker the material will be, the viscosity will increase, and the fluidity will decrease.

Refining equipment includes: three-roller refiner, five-roller refiner, drum refiner, etc. During the fine grinding process, attention should be paid to controlling the following operating procedures: adjusting the friction gap, adjusting the viscosity of the material, controlling the fine grinding temperature, and controlling the degree of fine grinding. There are certain limit requirements for the particle size of finely ground chocolate: if the particle size is too large or too many large particles, the taste will be rough; but if the particle size is too small or too many small particles, it will easily stick to our tongue and palate and will not be easily absorbed. Saliva is taken away from the mouth and makes people feel alive.

3. Refining: Although the refined chocolate has very fine texture, it is not delicate enough, and the aroma is not beautiful and mellow enough. Refining can further improve its quality. Especially high-end chocolate requires a refining process.

Refining is carried out in the refining machine. There are many types of refining machines, and the most commonly used one at present is the rotary refining machine. The material undergoes repeated friction and collision in the refining machine, which further smoothes and finely refines the material. The moisture and volatile odor in the material are driven away, and the material is fully emulsified, thereby improving the quality of the chocolate.

The main conditions required for refining are temperature and time. The requirements for the edge temperature of the plasmid vary with the variety of chocolate candy. Dark chocolate is 55-85℃; milk chocolate is 45-60℃. Fine grinding takes a long time, usually 24 to 72 hours.

Refining has the following effects: the quality of the chocolate is more delicate and smooth; the material becomes thinner and more fluid, and the color, aroma and taste are improved.

The phospholipids to be added during refining are extracted from soybean, sunflower and other oils.

Phospholipids have dual properties of lipophilic and hydrophilic. It has both lipophilic and hydrophilic groups. Its hydrophilic end can also be adsorbed by sugar, cocoa and milk solids. In this way, it plays a surface active role in the chocolate material, making the material into a highly stable milky state, so phospholipids are also emulsifiers.

Phospholipids can change the interfacial tension between plasmids, reduce the occurrence and strengthening of hydration of the material micelles, thereby hindering the formation of jelly, playing a diluting role, and reducing the viscosity of the material.

If more than 0.6% phospholipid is added to the chocolate material, the viscosity will no longer decrease. Therefore, the amount of chocolate added in chocolate candy production is between 0.1-0.5.

Adding phospholipids to chocolate candies can reduce a certain proportion of cocoa butter, which makes economic sense.

Phospholipids can also prevent the oxidation of oils and are also antioxidants.

4. Temperature adjustment: The function of temperature adjustment is to control the phase transition of cocoa butter at different temperatures, thereby achieving the effect of tempering.

To turn liquid chocolate sauce into solid chocolate candy, it is best to go through the tempering stage. Without temperature control or poor temperature control, the quality of the product will be poor.

From the perspective of the requirements of the production process, the chocolate material that changes from liquid to solid is required to have obvious shrinkage, so that it can easily fall out of the molded model. This is the requirement of the continuous production line. Necessary requirements. Temperature adjustment according to the requirements of process conditions can produce obvious shrinkage performance of the chocolate material. Conducive to demoulding and continuous production.

After cold solidification of chocolate that has not been tempered or has not been tempered well, the product will have a rough texture, a dark color, and lack of the brittle characteristics that chocolate should have. During the preservation process, it is easy to become rough and nest-like in texture, losing commercial value. Therefore, tempering is an important process in chocolate production.

Chocolate material contains about 30% cocoa butter. Cocoa butter is a continuous phase in the dispersion system, and its state determines the physical properties of chocolate. The changes in chocolate material during tempering are essentially changes in the polymorphic properties of cocoa butter. The purpose of tempering is to produce the highest proportion of crystalline form of the chocolate material, so that the chocolate production process is smooth and the quality of the finished product is stable.

The refined chocolate material is generally above 45°C, and its plasmids are in motion and cannot form any crystal form of cocoa butter. Therefore, the material in the storage tank needs to be stirred for a certain period of time before temperature adjustment.

In the first stage of temperature adjustment, the material is cooled from 45°C to 29°C. The cocoa butter produces crystal nuclei and gradually transforms into other crystal forms.

In the second stage of temperature adjustment, the material continues to cool from 29°C to 27°C, and some unstable crystal forms transform into stable crystal forms, with the quantity increasing and the viscosity increasing.

In the third stage of temperature adjustment, the material rises from 27°C to 29~30°C. The purpose is to dissolve the unstable crystal forms below 29°C and retain only the stable crystal forms. This is Crystal form. At the same time, the viscosity of the material is reduced, which is suitable for the requirements of the molding process.

The temperature adjustment process is a delicate process, and the temperature adjustment and control must be very strict and accurate. At present, there is no ideal temperature control machine, but the film-type continuous temperature control machine is suitable for mass production needs.

After the chocolate material is tempered, it can be used to produce chocolate candies. According to the molding process, chocolate candies can be divided into casting molding and coating molding.

5. Casting molding: The temperature and viscosity of the chocolate material used in the casting mold must be strictly controlled. The material temperature is required to be around 30°C. If the temperature is too high, the cocoa butter crystal form that has formed a stable crystal form will be destroyed. The finished product has a loose texture, lacks shrinkage characteristics, is difficult to demould, and is prone to spots or darkening during storage. If the temperature is too low, the material will be viscous, making it difficult to distribute quantitatively during mold casting, and it will be difficult to eliminate air bubbles in the material, making the product prone to honeycombs. Therefore, during the molding process, the material should always maintain an accurate temperature and be kept within the minimum temperature difference range.

Viscosity is another important factor in material requirements. The viscosity of the material also affects its fluidity and distribution accuracy. Therefore, the viscosity range of the material must be maintained during the molding process. After casting, the model must be shaken to make the finished product solid and prevent bubbles or voids from forming. The amplitude is required to be no more than 5 mm, and the frequency is about 1,000 times per minute.

The heat present in chocolate sauce comes in two forms: sensible heat and latent heat. Sensible heat refers to the heat released when the chocolate sauce lowers its temperature; latent heat refers to the heat released when the liquid changes to a solid state. The sum of the two types of heat is all the heat that needs to be removed during the molding process.

The requirements for the cooling process are: after casting the mold, first place it in a cold room at 8 to 10°C. For about 5 minutes, the material temperature will drop to 21°C; after another 21 minutes, the material temperature will drop to 21°C. If the temperature drops by 12°C, the total time required for cooling is 25 to 30 minutes. The cooling rate depends on the cooling temperature, cooling air method and product shape.

The cooling rate from liquid to solid cannot be too fast. The cooling temperature is generally 8~10℃, which can be appropriately increased to 12~14℃ in the later stage of cooling. The appropriate cold air speed is 7 meters per second. When the chocolate block shrinks and deforms, it reaches the end of cooling.

6． Coating and molding process: Candies made from coated and molded silk are called sandwich chocolates. Most of them are named after the filling, such as peanut-filled chocolate, protein-filled chocolate, etc.

The coating molding process has the following requirements:

(1) Core making and requirements for the core: the nature, color, and aroma of the core must be able to be harmoniously combined with the chocolate coating, specifically The requirements are that it has a soft texture, is easy to dissolve, is not sticky, and does not cause morphological changes, penetration and perforation, expansion and contraction, rancidity, insect infestation, mildew, etc. When painting, the core temperature should generally be about 5°C lower than the outer temperature.

(2) Coat making and requirements for coating: The cocoa butter in the chocolate material used for coating is higher than that of the material used for casting molds. The chocolate sauce used for coating must have appropriate viscosity and fluidity. Materials that are too thick are not only inconvenient to transport, but also distributed unevenly. The coating thickness is uneven, and the consumption quota cannot be guaranteed.

During the entire coating process, the temperature adjustment requirements of the sauce must always be strictly controlled and maintained at 30 to 33°C.

(3) Control cooling speed: The cooling channel of the coating forming unit should be maintained at 7 to 12°C, the cold air speed should not exceed 7 meters/second, and the cooling time should be maintained at 15 to 20 minutes. The temperature in the later stage of cooling can be Slightly higher and conducted under drier conditions.

7. Chocolate candy packaging: The main functions of packaging are: heat protection, moisture absorption and melting prevention, aroma escape, grease precipitation and rancidity prevention, mildew prevention, insect prevention, and pollution prevention. The requirements for packaging are to be beautiful, colorful, and able to maintain the color, aroma, taste, and shape of chocolate candies for a long time, especially in hygienic conditions.

General wax paper is difficult to meet the above requirements. Commonly used packaging materials include: aluminum foil, polyethylene, polypropylene, polystyrene, etc. Aluminum foil ~ polyethylene composite materials or other composite materials are also used.