RU2316974C1 - Method for producing of fried coffee products - Google Patents

Abstract

FIELD: food-concentrates industry, in particular, process used in lines for processing of coffee products, preferably chicory and coffee beans, barley, rye, soya, etc.

SUBSTANCE: method involves preparing raw material; performing thermal processing by means of overheated steam and intermediate wetting of product; providing two-staged thermal processing of coffee products: first stage including processing beans or particles of coffee products with air having temperature of 150-210 C in fluidized bed during 10-35 min, followed by milling to 1.0-2.0 mm sized particles, and moistening with finely dispersed moisture to moisture content of 7-8%, followed by holding for uniform distribution of moisture through the volume of moistened product; second stage including processing coffee products with overheated steam in dense interspersing layer until moisture content reaches 4% and acidity is 4.0-5.6; cooling fried coffee products to temperature of 35 C; grinding to 0.2-0.3 mm size particles; sieving and mixing milling products (coffee, chicory, rye, barley, etc).

EFFECT: improved quality of ready product, increased yield, and provision for creating of ecologically clean process for producing of fried coffee products.

1 dwg

Description

The invention relates to food-concentrate industry and can be used in the processing lines of coffee products, mainly chicory and coffee beans, barley, rye, soy, etc.

The closest in its technical essence and the achieved effect is a method of roasting coffee beans, where superheated atmospheric pressure steam with a temperature of 280 ... 380 ° C and a speed of 2.8 ... 3.6 m / s is used as a heat carrier, processing is carried out 4 min, and in the middle and at the end of the roasting process, coffee grains are moistened with finely dispersed moisture for 10 ... 15 s, bringing the moisture content to 8% after the first moistening, and to 5 ... 6% after the second [A. No. 1734642 of the Russian Federation, MKI ⁵ A23F 05/04. The method of roasting coffee beans / V.M. Kravchenko, A.N. Ostrikov (RF). - No. 4646955/13. Claim 02/07/89. Publ. 05/23/92. Bull. No. 19 // Inventions. - 1992. - P.16].

However, the known method does not allow for uniform and high-quality frying of the product, which leads to a decrease in the quality and yield of finished products. The method does not provide for the maintenance of rational thermo-humid (humidity and temperature) parameters of coffee products during the roasting process, which determine the amount of fumes. Burnout (this is a mixture of evaporated moisture from coffee products and non-condensable gases - components of thermal decomposition of coffee products) during frying is 12 ... 20% of its total product mass and includes toxic components that have a negative effect on human health. On the other hand, a decrease in fumes will reduce the loss of extractive substances and increase the yield of finished products. The method does not provide for the removal of gaseous components of thermal decomposition of coffee products that contain harmful substances (for example, carcinogenic hydrocarbons: 3,4-benzopyrene, flurantene, etc.).

The known method does not create conditions for the implementation of environmentally friendly, resource-saving technology for obtaining roasted coffee products.

An object of the invention is to improve the quality of the finished product, increase its output and create an environmentally friendly technology for the production of roasted coffee products.

The technical result is that:

- due to the constant removal of gaseous components formed as a result of thermal decomposition of the cellular system of coffee raw materials and having a high content of carcinogenic hydrocarbons: 3,4-benzopyrene, fluranten, etc., the quality of the finished product increases;

- due to the reduction of fumes due to phased roasting with stepless regulation of thermal humidity (humidity and temperature) product parameters, the yield of finished products increases.

The problem is achieved in that in a method for the production of roasted coffee products, involving the preparation of raw materials, heat treatment with superheated steam with intermediate wetting of the product, it is new that the heat treatment of coffee products is carried out in two stages, at the first stage, grains or particles of coffee products are treated with air with a temperature of 150 ... 210 ° C in a fluidized bed for 10 ... 35 min, then grind to a particle size of 1.0 ... 2.0 mm, then moisten with finely dispersed moisture to a moisture content of 7 ... 8% followed by baking to evenly distribute moisture throughout the humidified product, in the second stage, the coffee products are treated with superheated steam in a dense, sprinkled layer until a moisture content of 4% and an acidity of pH 4.0 ... 5.6 are reached, then the fried coffee products are cooled to a temperature of 35 ° C, subjected to grinding to a size of 0.2 ... 0.3 mm, sieved and grinding products (coffee, chicory, rye, barley, etc.) are mixed.

The drawing shows a diagram that implements the proposed method for the production of roasted coffee products.

The scheme contains a production hopper 1 for storing raw coffee products (coffee, chicory, barley, rye, etc.) with a drum batcher 2, a vibratory separator 3, a cyclone unloader 4, a multi-section hopper 5, scales 6, a granulator 7, a fryer 8, a stabilizer thermo-humid characteristics of coffee products 9, drum fryer 13, cooling bowl 14, grinder 15, sifter 16, mixer 17 and filling machine 18. The stabilizer 9 of the thermo-humid characteristics of coffee products includes a conveyor belt passing through h two chambers: a humidification chamber 11 with nozzles 10 for supplying water and a chamber 12 for tracing the moistened product.

Method for the production of roasted coffee products is as follows.

Prepared raw materials (washed and refined chicory, coffee grains, rye, barley, soybeans, etc.) from the production hopper 1 for storing raw coffee products with a drum dispenser 2 are fed into a vibration separator 3, which separates impurities by aspiration, sifting and passing through magnetic traps . Light impurities (dust) are taken away by the fan and deposited in removable barrels of cyclones. The separator 3 is equipped with stamped metal sieves with holes of the following sizes (in mm): a trap with oval cells 9 × 16 or 13 × 16, sorting (passage with rhombic cells) 10 × 17, a gathering wire sieve with square cells 2 × 6 or 1, 5 × 20.

Then the cleaned and sorted product from the separator 3 is fed through the pneumatic conveyor system and transported by a stream of purified air to the cyclone unloader 4, from which it is sent to a four- or six-section hopper 5. The loading of the sections of the hopper 5 is fixed by the sensor. Before serving the next type of coffee product in the separator 3, the previous type must be fully loaded into the appropriate section. At the end of the separator 3, the waste is removed from the receivers and the magnets are cleaned.

Then, a certain portion of the product weighed with the help of scales 6 is fed into the fryer 8 for the first stage of frying.

At the same time, air with a temperature of 150 ... 210 ° C is supplied to the fryer 8 with a speed that provides frying of the product particles in the fluidized bed for 10 ... 35 min. Due to the fact that the particles of the product (coffee, barley, rye, soy, chestnut, etc.) grains are not crushed at this stage of frying, i.e. they are whole, the negative effect of atmospheric oxygen is minimized and limited only to the surface layers.

Roasting of each type of coffee product (coffee of different varieties and types, grain of barley, rye, soy, chestnut, etc.) is carried out separately. The modes of roasting coffee, chicory, barley and rye are given in table 1.

Table 1 Coffee Roasting Modes Raw materials Apparatus The mass of the loaded raw materials, kg Temperature ° C Duration of frying, min Arabica coffee "Probate" 240 ... 300 180 ... 210 14 ... 15 Chicory Rapido 240 180 ... 210 10 ... 12 Barley A-9ZHK-A 120 ... 150 140 ... 160 35 Rye Lindgrenz 120 ... 150 155 ... 160 thirty

Let us dwell in more detail on the mechanism of the process of roasting coffee products. Due to the fact that the roasting process, depending on the type of processed raw materials (coffee, chicory, soy, chestnuts and other products) includes two stages of roasting with intermediate grinding and moistening, a coolant with the parameters necessary for this stage is supplied at each stage. Preheating of the product proceeds evenly over the entire surface, the bond strength of moisture with the product decreases, which accelerates subsequent frying. A smooth increase in the temperature of the raw materials in the first stage of roasting allows you to remove surface moisture, reduce moisture by 3.1 ... 3.6% and activate the diffusion ability of the capillary-porous structure of the product to remove adsorption-bound moisture in the second stage of roasting [Ostrikov A.N ., Shevtsov A.A., Kravchenko V.M., Zotov A.N. Roasting coffee with superheated steam / Voronezh. state technol. Acad. Voronezh, 2003, 174 p.].

In this case, a gradual increase in the temperature of the grains occurs without overdrying their surface layers. Processing in a fluidized bed promotes uniform heating of grains throughout the volume of the layer.

Roasting coffee is a pyrogenic process (pyrolysis) in which organic substances are heated to high temperatures. As a result of roasting, a peculiar taste and aroma inherent in coffee are formed. Coffee beans undergo significant physical and chemical changes. Grains increase in volume, their mass decreases as a result of evaporation of moisture and decomposition of sugars, fiber and other organic substances of grains. Sugar is caramelized with the formation of caramel, and its quantity, and consequently, the color intensity of coffee beans, depends on the time and temperature of roasting.

As a result of high temperature, fiber undergoes dry distillation with the formation of acetic and other organic acids and acetone.

Pentosanes are also decomposed, their content in coffee reaches 6 ... 7%. When decomposed, they form furfural and furfural alcohol.

Coffee fat, consisting mainly of oleic acid and contained in grains in an amount of 10 ... 13%, changes slightly, forming acrolein.

The proteinaceous substances of coffee, which contain 9 ... 11%, also undergo changes under the influence of a high roasting temperature, forming ammonia, amines, pyrrole, etc. All substances released from complex organic compounds of coffee beans, under the influence of high temperature, enter into a reaction with each other, forming new compounds, which determine the aroma of valuable coffee. This complex of compounds is collectively called caffeol. Therefore, it is advisable to roast coffee raw materials in the first stage of roasting to a moisture content of 7 ... 8%.

At the same time, the amount of fumes decreases to 10 ... 12% and, as a result, the loss of extractive substances decreases and the yield of finished products increases. Thermal decomposition products - carcinogens are continuously removed with non-condensed gases, while creating environmentally friendly conditions in the production technology of high-quality coffee products.

For example, the duration of the roasting of one portion of Robusta coffee (240 ... 300 kg) is 13 ... 18 min at a temperature of 180 ... 210 ° C in the apparatus of the Probat type.

If the roasting at the first stage is carried out with air with a temperature below 150 ° C in a fluidized bed, for example 140 ° C, then the roasting time increases significantly and not all coffee products (coffee, chicory, chestnuts, etc.) will be roasted to the desired condition due to insufficient high temperature.

If the roasting at the first stage is carried out with air with a temperature above 210 ° C in a fluidized bed, for example 220 ° C, then this will lead to the burning of coffee products.

If roasting at the first stage is carried out for less than 10 minutes, for example 8 minutes, then coffee products (coffee, chicory, chestnuts, etc.) will not be roasted to the desired condition, because during this time, their humidity will not be brought to the set values.

If the roasting at the first stage is carried out for more than 35 minutes, for example 40 minutes, this will lead to the burning of coffee products.

Then the roasted coffee product is sent to a granulator 7, which consists of five rollers, three of which are pre-crushed coffee, and two bring the particles of the product to 1 ... 2 mm, turning them into grains. Particles of precisely this size (grains) are most optimal for subsequent saturation with moisture. If the particle size is less than 1 mm, for example 0.4 mm, then when moistened with finely dispersed moisture, they stick together easily, clump together and are difficult to process further. If the particle size is more than 2 mm, for example 4 mm, then when moistened with finely dispersed moisture, they need considerable time to evenly distribute moisture throughout the volume of the particles. Therefore, during further processing (the second stage of frying), they burn, which leads to a deterioration in their quality.

After grinding, the particles of the coffee products are sent to the stabilizer of the thermo-humid characteristics of the coffee products 9, where they fall onto the conveyor belt, which sequentially moves them through the humidification chamber 11 and the chamber 12 for tracking the moistened product. At the same time, finely dispersed water is supplied through nozzles 10 located in the humidification chamber 11, which, being sprayed over the product layer, moisturizes the particles (grains) of coffee products to a moisture content of 7 ... 8%. The fried coffee product is moistened to a moisture content of 7 ... 8% to avoid the formation of small particles during grinding. For this, the stabilizer of the thermo-humid characteristics of the coffee products 9 is supplied for a certain time with a predetermined amount of water and the outlet is closed with flue gas. This reduces the deodorization of coffee and reduces the loss of aromatic substances.

The humidification of the coffee product after roasting is aimed at increasing the humidity of the product for faster cooling, preventing the combustion of the fine fraction and reducing the pulverulent fraction during subsequent grinding. If the particles of the product are moistened to a moisture content of less than 7%, for example up to 6%, this will contribute to the formation of small particles during grinding. If the particles of the product are moistened to a moisture content of more than 8%, for example, up to 9%, then significant energy consumption will be required in the second stage of frying to bring the product to a predetermined final moisture content due to its overmoistening.

Then the moistened particles are slowly fed by a conveyor belt into the chamber 12, where moisture is distributed over the entire volume of particles and preparation for the second stage of frying.

From the stabilizer 9, the particles of coffee products (grains) are sent to a drum fryer 13, which also provides superheated steam.

At the second stage, roasting takes place in a dense overgrowth layer until a moisture content of 4% and an acidity of pH 4.0 ... 5.6 are reached. The process of roasting at the second stage in a dense overflowing layer (and a rotating drum fryer provides precisely this hydrodynamic regime) is due to the fact that the particle size is very small (1 ... 2 mm) and when processed in a fluidized bed they are easily susceptible to entrainment. Therefore, additional equipment would be required: filters, cyclones, etc., which greatly complicated the line.

Due to the fact that the product particles (coffee grains, barley, rye, soybeans, etc.) are crushed at this stage of frying, and the heat carrier - superheated steam is inert, because does not contain oxygen, then the most rational conditions are created for the optimal course of the second stage of frying.

The final moisture content of the roasted coffee particles of 4% provides the best conditions for storage and subsequent preparation of the drink. If the humidity of the roasted coffee particles is less than 4%, for example 3%, then with further storage they easily absorb moisture (because they are very hygroscopic), which affects their quality. If the humidity of the roasted coffee particles is more than 5%, for example 6%, then upon further storage, microflora can actively develop in them, which affects their quality. The choice of the optimum humidity of 4% is due to the fact that for most coffee products, the hygroscopic humidity ranges from 3.6 ... 4.1%.

Uniform roasting of raw materials is an important factor in obtaining a product with good taste, color and aroma. The roasting modes are regulated and the optimum degree of roasted semi-finished product is set upon reaching roasted coffee pH 4.0 ... 5.6, chicory - 4.6 ... 4.8.

The choice of the acidity range of pH 4.0 ... 5.6 fried particles is due to the fact that the authors found that when the temperature is increased from 30 to 90 ° C, volatile components with a grassy odor and low-volatile components that do not have a pronounced smell of roasted coffee are released. Starting from 90 ° C, in volatile products, the concentration of low-volatile components sharply increases. From chromatographic data it follows that it is these components that characterize the smell of roasted coffee. Their formation is apparently caused by the processes of thermal destruction of substances of coffee beans and the decomposition of low-volatile components. The formation of a large number of volatile substances, starting at 168 ° C, recorded by chromatography, is confirmed by the method of differential thermal analysis [Study of coffee beans by the method of differential thermal analysis / Shevtsov A.A., Ostrikov A.N., Kuznetsova I.V., Zotov A.N. // Storage and processing of agricultural raw materials. - 2002. - No. 10. - S.28-29].

The method of vapor-phase gas chromatographic analysis revealed the characteristic gaseous fractions formed during the thermal decomposition of coffee at different temperatures, the dynamics of the ratios of which are taken into account when optimizing the temperature regime of coffee roasting [A.A.Shevtsov, A.N. Ostrikov, O.B. Rudakov, I.V. Kuznetsova, A.N. Zotov. Chromatographic analysis of the volatile coffee constituents produced by roasting. // News of universities. Food technology. - 2003. - No. 1. - S.19-21].

For example, the acidity of roasted Robusta coffee should be 5.2 ... 5.4 pH, and the content of extractives for coffee of the first grade at least 25%, for coffee of the second grade - 27.5%.

Then the roasted coffee is cooled in a cooling bowl 14 to a temperature of 35 ° C. If the temperature of the cooled particles is less than 35 ° C, for example 25 ° C, then upon further grinding they become more fragile and crush with the formation of a significant amount of flour, which worsens the process of extraction of water-soluble substances in the preparation of a coffee drink. If the temperature of the particles is more than 35 ° C, for example 45 ° C, then with further grinding they become ductile and poorly crushed. The optimum temperature value of 35 ° C is due to the fact that coffee fat, consisting mainly of oleic acid and contained in grains in an amount of 10 ... 13%, has a melting point of 37 ... 39 ° C. Therefore, heating above this temperature is impractical.

The cooled particles are sent to the crusher 15, in which they are subjected to grinding to a size of 0.2 ... 0.3 mm. The size of the granules of crushed grains is important. It is known that the speed of the extraction process is inversely proportional to the size of the particles, it decreases with their increase, therefore it is advantageous to have the smallest particles of the product subjected to extraction. But a significant reduction in particle size leads to a deterioration in the wettability and filtration conditions of the extract.

Particles of size 0.2 ... 0.3 mm are most optimal for the subsequent preparation of a coffee drink. If the particle size is less than 0.2 mm, for example 0.1 mm, then when brewing coffee, they easily stick together, clump and poorly extract water-soluble substances into the drink. If the particle size is more than 0.3 mm, for example 0.4 mm, then when preparing a coffee drink, they need considerable time to extract water-soluble substances.

Next, the crushed particles are sent to the sifter 16.

The grinding products of coffee, chicory, barley, etc. are mixed in a predetermined proportion in a mixer 17. The mixture is packaged on a filling machine 18.

Example 1. The technology of production of fried chicory.

The chicory roots received for processing are first subjected to washing, as a result of which foreign impurities and microorganisms are removed. After washing, chicory goes to cutting, where it is cut into cubes, columns or plates with dimensions respectively, mm: 10-20 × 10-20 × 10-20; 20-60 × 12-15 × 5-10; 10-20 × 15-20 × 5-7 [Handbook of the technologist of food-concentrate and vegetable drying production / V.N. Gulyaev, N.V. Dremina, Z.A. Kats and others. - M .: Light and food industry, 1984, - 488 p., P. 341-342].

Prepared chicory from the production hopper 1 with a drum batcher 2 is fed into a vibration separator 3, which separates impurities by aspiration, sieving and passing through magnetic traps.

Then, the peeled and sorted chicory from the separator 3 is fed to the cyclone unloader 4, from which it is sent to a four- or six-section hopper 5. The loading of the sections of the hopper 5 is fixed by the sensor.

Then weighed using scales 6 a certain portion of chicory is fed into the fryer 8.

At the same time, air with a temperature of 180 ... 210 ° C is supplied to the fryer 8 with a speed that provides frying of the product particles in the fluidized bed for 10 ... 12 minutes. The modes of roasting chicory are given in table 1.

Processing in a fluidized bed promotes uniform heating of chicory particles throughout the volume of the layer. At the same time, the amount of fumes decreases to 10 ... 12%, and, as a result, losses of extractive substances decrease, and the yield of finished products increases.

If the roasting of chicory in the first stage is carried out with air with a temperature below 180 ° C in a fluidized bed, for example 140 ° C, then the duration of roasting increases significantly, and the chicory will not be roasted to the desired condition due to the insufficient temperature.

If the roasting of chicory in the first stage is carried out with air with a temperature above 210 ° C in a fluidized bed, for example 220 ° C, then this will lead to a burning of chicory.

If the frying at the first stage is carried out for less than 10 minutes, for example 9 minutes, then chicory will not be fried until the required condition, because during this time, their humidity will not be brought to the set values.

If the frying in the first stage is carried out for more than 12 minutes, for example 20 minutes, this will lead to a burning of chicory.

Then the fried chicory particles are sent to granulator 7, which grinds chicory to 1 ... 2 mm. Particles of chicory of precisely this size are most optimal for subsequent saturation with moisture. If the particle size of chicory is less than 1 mm, for example 0.7 mm, then when moistened with finely dispersed moisture, they easily stick together, clump and are difficult to further process. If the particle size of chicory is more than 2 mm, for example 3 mm, then when moistened with finely dispersed moisture, they need considerable time to evenly distribute moisture throughout the volume of the particles. Therefore, during further processing (the second stage of frying), they burn, which leads to a deterioration in their quality.

After grinding, the chicory particles are sent to the stabilizer of the thermo-humid characteristics of the coffee products 9, where they enter the conveyor belt, which sequentially moves them through the humidification chamber 11 and the chamber 12 for tracing the moistened product. At the same time, finely dispersed water is supplied through nozzles 10, which, spraying over the product layer, moisturizes the chicory particles to a moisture content of 7 ... 8% to avoid the formation of small particles during grinding.

If chicory particles are moistened to a moisture content of less than 7%, for example up to 6%, this will contribute to the formation of small particles during grinding.

If the chicory particles are moistened to a moisture content of more than 8%, for example, up to 9%, then significant energy consumption will be required in the second stage of roasting to bring chicory to a given final moisture content.

Then, the moistened chicory particles by a slowly moving belt conveyor are fed into the chamber 12, where moisture is distributed over the entire volume of particles and preparation for the second stage of frying.

From the stabilizer 9, the chicory particles are sent to a drum fryer 13, into which superheated steam is also supplied.

At the second stage, the roasting of chicory occurs in a dense overgrowing layer until a moisture content of 4% and an acidity of pH 4.6 ... 4.8 are reached. The process of roasting at the second stage in a dense overflowing layer (and a rotating drum fryer provides precisely this hydrodynamic regime) is due to the fact that the particle size is very small (1 ... 2 mm) and when processed in a fluidized bed they are easily susceptible to entrainment.

A final moisture content of fried chicory particles of 4% provides the best conditions for storage and subsequent preparation of the drink. If the humidity of the fried chicory particles is less than 4%, for example 3%, then with further storage they easily absorb moisture, which affects their quality. If the humidity of the fried chicory particles is more than 5%, for example 6%, then upon further storage, microflora can actively develop in them, which affects their quality.

The choice of the acidity range of pH 4.6 ... 4.8 roasted chicory particles is due to the fact that, when the temperature rises from 40 to 100 ° C, the emission of volatile components with a grassy odor and low-volatile components that do not have a pronounced smell of roasted coffee is observed. Starting from 100 ° C, in volatile products, the concentration of low-volatile components sharply increases.

Then the fried chicory is cooled in a cooling bowl 14 to a temperature of 35 ° C. If the temperature of the chicory particles is less than 35 ° C, for example 25 ° C, then with further grinding they become more fragile and crush with the formation of a significant amount of dust fraction, which worsens the process of extraction of water-soluble substances. If the temperature of the chicory particles is more than 35 ° C, for example 45 ° C, then with further grinding they become plastic and poorly crushed.

Cooled chicory particles are sent to a crusher 15, in which they are subjected to grinding to a size of 0.2 ... 0.3 mm.

Next, the chopped chicory particles are sent to a sifter 16.

The grinding products of coffee, chicory, barley, etc. are mixed in a predetermined proportion in a mixer 17. The mixture is packaged on a filling machine 18.

Table 2 shows some indicators of fried chicory obtained by factory technology, according to the known method of frying with superheated steam (A.S. No. 1734642 of the Russian Federation) and the proposed method.

table 2 Quality indicators of fried chicory Indicators Fresh chicory Roasted chicory by traditional technology by the method (Pat. No. 2203553) by the proposed method Water 73.1 4.0 4.0 4.0 Extractives 21,4 74.2 ... 76.0 77.3 77.3 Inulin 16.6 24.0 26.5 27.3 Common sugar 4.0 18.2 21,2 23.0 Reducing sugar 3.39 14.1 15.9 16,4 Ash (total) 1,07 4,5 4,5 4.7 pH 5.7 4,5 4.3 4.4

Example 2. The technology of production of roasted coffee beans "Arabica". The prepared Arabica coffee from the production hopper 1 with a drum dispenser 2 is fed into a vibration separator 3, which separates impurities by aspiration, sifting and passing through magnetic traps. Next, purified and sorted coffee "Arabica" from the separator 3 is fed into the cyclone unloader 4, from which it is sent to a four- or six-section hopper 5.

Then weighed using scales 6 a certain portion of coffee "Arabica" is served in the roaster 8.

At the same time, air with a temperature of 180 ... 210 ° C is supplied to the fryer 8 at a speed that provides frying of the product particles in the fluidized bed for 14 ... 15 minutes. The modes of roasting Arabica coffee are shown in Table 1.

Processing in a fluidized bed promotes uniform heating of coffee beans "Arabica" throughout the volume of the layer. At the same time, the amount of fumes decreases to 10 ... 12%, and, as a result, losses of extractive substances decrease, and the yield of finished products increases.

If the roasting of Arabica coffee beans at the first stage is carried out with air with a temperature below 150 ° C in a fluidized bed, for example 140 ° C, then the roasting time increases significantly and the coffee grains will not be roasted to the desired condition due to insufficient heat.

If the roasting of Arabica coffee beans in the first stage is carried out with air with a temperature above 210 ° C in a fluidized bed, for example 220 ° C, then this will lead to burning of Arabica coffee beans.

If the roasting of Arabica coffee beans in the first stage is carried out for less than 10 minutes, for example 8 minutes, then the Arabica coffee beans will not be roasted to the desired condition, because during this time, their humidity will not be brought to the set values.

If the roasting of Arabica coffee beans in the first stage is carried out for more than 35 minutes, for example 40 minutes, this will lead to their burning.

Then, the roasted Arabica coffee beans are sent to granulator 7, which grinds coffee beans to 1 ... 2 mm. Particles of Arabica coffee of precisely this size are most optimal for subsequent saturation with moisture. If the particle size of Arabica coffee is less than 1 mm, for example 0.5 mm, then when moistened with finely dispersed moisture, they stick together easily, clump together and are difficult to process further. If the particle size of Arabica coffee is more than 2 mm, for example 3 mm, then when moistened with finely dispersed moisture, they need considerable time to evenly distribute moisture throughout the volume of the particles. Therefore, during further processing (the second stage of frying), they burn, which leads to a deterioration in their quality.

After grinding, the Arabica coffee particles are sent to the stabilizer of the thermo-humid characteristics of the coffee products 9, where they enter the conveyor belt, which subsequently moves them through the humidification chamber 11 and the chamber 12 for tracing the moistened product. At the same time, finely dispersed water is supplied through nozzles 10, which, spraying over the product layer, moisturizes the particles of Arabica coffee to a moisture content of 7 ... 8% to avoid the formation of small particles during grinding.

If the particles of Arabica coffee are moistened to a moisture content of less than 7%, for example up to 6%, this will contribute to the formation of small particles during grinding.

If the particles of Arabica coffee are moistened to a moisture content of more than 8%, for example, to 9%, then significant energy consumption will be required in the second stage of roasting to bring the Arabica coffee to a given final moisture content.

Then, the moistened particles of Arabica coffee are fed into the chamber 12 by a slowly moving belt conveyor, where moisture is distributed over the entire volume of particles and preparation for the second stage of roasting is performed.

From the stabilizer 9, Arabica coffee particles are sent to a drum fryer 13, into which superheated steam is also supplied.

At the second stage, the roasting of Arabica coffee particles occurs in a dense, sprinkling layer until a moisture content of 4% and an acidity of pH 4.0 ... 5.6 are reached. The conduct of the roasting process in the second stage in a dense overflowing layer (and a rotating drum fryer provides precisely this hydrodynamic regime) is due to the fact that the particle size of Arabica coffee is very small (1 ... 2 mm) and they are easy to process in a fluidized bed subject to ablation.

The final moisture content of the roasted particles of Arabica coffee 4% provides the best conditions for storage and subsequent preparation of the drink. If the humidity of the roasted particles of Arabica coffee is less than 4%, for example 3%, then with further storage they easily absorb moisture, which impairs their quality. If the humidity of the roasted particles of Arabica coffee is more than 4%, for example 6%, then with further storage, microflora can actively develop in them, which affects their quality.

The choice of the acidity range of pH 4.0 ... 5.6 roasted particles of Arabica coffee is due to the fact that, when the temperature rises from 40 to 100 ° C, volatile components with a grassy odor and low-volatile components that do not have a pronounced odor are released roasted coffee. Starting from 100 ° C, in volatile products, the concentration of low-volatile components sharply increases.

Then the roasted coffee "Arabica" is cooled in a cooling bowl 14 to a temperature of 35 ° C. If the temperature of the particles of coffee "Arabica" is less than 35 ° C, for example 30 ° C, then with further grinding they become more fragile and crush with the formation of a significant amount of dust fraction, which worsens the process of extraction of water-soluble substances. If the temperature of the particles of coffee "Arabica" is more than 35 ° C, for example 40 ° C, then with further grinding they become plastic and poorly crushed.

Cooled particles of coffee "Arabica" is sent to the grinder 15, in which it is subjected to grinding to a size of 0.2 ... 0.3 mm

Next, the crushed particles of Arabica coffee are sent to a sifter 16. The products of grinding coffee, chicory, barley, etc. are mixed in a predetermined proportion in a mixer 17. The mixture is packaged on a filling machine 18.

The proposed method has the following advantages:

- obtaining a product of higher quality due to the continuous withdrawal of non-condensed gases containing carcinogenic hydrocarbons: (3,4-benzopyrene, flurantene, etc.);

- an increase in the yield of finished products by reducing the mass fraction of non-condensed gases through the use of two-stage processing with intermediate humidification and bedding, without excessive exposure to high temperatures with a gradual decrease in the moisture content of coffee raw materials;

- An environmentally friendly, resource-saving technology for the production of roasted coffee products was developed;

- the ability to improve the quality of the resulting product by reducing fumes and increasing the café up to 2.0% due to the use of softer, “sparing” modes and uniform processing;

- optimization of the roasting process of various feedstock due to the "automatic" maintenance of the heat-moisture regime due to the regulation of the temperature of the product in the frying zones and humidity in the humidification zones.

Claims (1)

A method for the production of roasted coffee products, involving the preparation of raw materials, heat treatment with superheated steam with intermediate moistening of the product, characterized in that the heat treatment of coffee products is carried out in two stages, at the first stage, grains or particles of coffee products are treated with air with a temperature of 150 ÷ 210 ° C in a fluidized bed in during 10 ÷ 35 min, then grind to a particle size of 1.0 ÷ 2.0 mm, then moisten with finely dispersed moisture to a moisture content of 7 ÷ 8%, in the second stage, the coffee products are processed with unheated steam in a dense pouring layer until a moisture content of 4% and an acidity of pH 4.0 ÷ 5.6 are reached, then the fried coffee products are cooled to a temperature of 35 ° C, subjected to grinding to a size of 0.2 ÷ 0.3 mm, sieved and grinding products ( coffee, chicory, rye, barley, etc.) are mixed.