RU2538816C1 - Dried garlic production method - Google Patents

Abstract

FIELD: food industry.

SUBSTANCE: method involves washing, cutting off ends and fibrils of garlic, dividing garlic into cloves, sorting, pneumo-peeling, drying, milling, sieving, packing and packaging of the ready product. Garlic cut into slices with thickness equal to 3 mm is subjected to combined UHF-convective drying. Drying is performed by way of exposing the product to a UHF electromagnetic field with a frequency equal to 2450 MHz and with convective blowing with air having initial temperature equal to 293 K in three temporal stages. At the first stage, garlic slices are heated with UHF-waves till the temperature is equal to 300 K with simultaneous blowing at an air flow rate equal to 0.9 m/s during 7.5 minutes. At the second stage heating is performed till the temperature is equal to 316 K at an air flow rate equal to 0.7 m/s during 12 minutes. At the third stage heating is performed till the temperature is equal to 320 K at an air flow rate equal to 0.5 m/s during 20 minutes.

EFFECT: invention implementation allows to enhance the ready product quality.

1 dwg, 1 tbl

Description

The invention relates to food, in particular to vegetable drying and food concentrate, industry, and can be used for the production of dried garlic.

A known method for the production of dried garlic [Handbook technologist food concentrate and vegetable drying production [Text] / B. N. Gulyaev, N.V. Dremina, Z. A. Katz / ed. V.N. Gulyaev. - M .: Light and food industry, 1984. - 488 p.], Providing for crushing teeth, inspection, cutting, drying in two stages: at the first stage - at a temperature of 50-60 ° C to a moisture content of 14-17% and at the second stage - at a temperature of 55-40 ° C to a moisture content of not more than 8% (drying), otveivanie scales, crushing, packing and packaging.

The disadvantages of this method are: the low quality of the dried product due to the uneven removal of moisture from the processed material, high process time, high energy consumption due to the low heating rate of the product.

An object of the invention is to improve the quality of the finished product and increase the thermal efficiency of the drying process through the use of a stepped regime of microwave convective drying of garlic, reducing energy consumption to obtain the finished product, and intensifying the drying process.

The object of the invention is achieved by the fact that in the proposed method for the production of dried garlic, including washing, trimming the ends and lobes of garlic, dividing the garlic into cloves, sorting, air cleaning, drying, grinding, sifting, packaging and packaging of the finished product, new is that garlic, cut into 3 mm thick plates, is subjected to combined microwave convective drying, which is carried out by exposing the product to a microwave electromagnetic field with a frequency of 2450 MHz and convective by blowing air with an initial temperature of 293 K in three time steps: at the first stage, the garlic plates are heated by microwave waves to a temperature of 300 K while simultaneously blowing with an air stream at a speed of 0.9 m / s for 7.5 min; at the second stage - up to a temperature of 316 K and an air flow rate of 0.7 m / s for 12 minutes; in the third stage, up to a temperature of 320 K and an air flow velocity of 0.5 m / s for 20 minutes.

The technical result of the invention is to improve the quality of the finished product through the use of stepwise modes of combined microwave convective drying of garlic, increasing thermal efficiency and intensification of the drying process, in reducing energy consumption for obtaining the finished product.

In FIG. Figure 1 shows the kinetic laws of the stepped regime of combined microwave convective drying of garlic: а - drying curve, drying speed curve; b - temperature curve; in - thermogram.

Fresh garlic, coming into processing, in its quality must meet the technical conditions of GOST 7977-87 and meet the following requirements:

in appearance: the bulbs are ripe, solid and dense, healthy, clean, whole, not germinated, without damage by agricultural pests, in shape and color typical of the botanical variety, with dry covering scales, for arrow varieties - with a trimmed arrow no more than 20 mm, for non-shooters - with cut dry leaves no more than 50 mm long inclusive, with or without dry root residues.

Smell and taste - characteristic of this botanical variety, without extraneous smell and taste;

By size - the size of the bulbs by the largest transverse diameter of at least 25 mm;

Mechanical damage - the content of bulbs with minor mechanical damage of not more than 3.0% by weight;

Damage by pests and diseases is not allowed.

Rotting fruit, steaming or freezing is not allowed.

The chemical composition is variable and is closely dependent on climatic conditions, cultivation techniques and variety.

The content of toxic elements, pesticides and nitrates in garlic should not exceed acceptable levels established by biomedical requirements and sanitary standards for the quality of food raw materials and food products.

Garlic arriving for processing must be fresh, healthy and properly colored.

A method of manufacturing dried garlic is as follows.

Garlic is served in a washer - in a bathtub on an inclined grate. There is a bubbler under the grill. The ascending air flows drive the garlic in the bath, intensifying soaking and separation of contaminants. From an inclined lattice, garlic falls onto a roller conveyor, where the process of separation of contaminants from raw materials continues due to friction of the slices when they are rotated by rotating conveyor rollers. When leaving the bath, the garlic is rinsed with clean water jets from the nozzles of the syringe collectors.

Then washed garlic is subjected to inspection and sorting, which is carried out manually on a sorting and inspection conveyor. Simultaneously with sorting, an inspection of raw materials is carried out, in which defective specimens (rotten, damaged, broken, moldy, heavily contaminated), foreign impurities and objects are removed. Treated garlic is cleaned of scales. Then the product is cut into 3 mm thick plates.

Cutting garlic into plates of more than 3 mm thickness, for example 4 mm, significantly increases the drying time and reduces the productivity of the line.

Cutting garlic into plates of less than 3 mm thickness, for example 2.0 mm, leads to a strong warping of garlic, which complicates its further processing.

Then chopped garlic plates are subjected to combined microwave convective drying. Moreover, the heating of garlic is carried out by exposing the product to a microwave electromagnetic field with a frequency of 2450 MHz while convectively blowing air with an initial temperature of 293 K in three time stages.

The choice of the frequency of oscillation of the microwave electromagnetic field, equal to 2450 MHz, due to the fact that this frequency accounts for the maximum electromagnetic energy, and this frequency corresponds to the maximum absorption capacity of the product. If the product is heated by a microwave electromagnetic field with a frequency of less than 2450 MHz, for example 2250 MHz, then this frequency will not be enough to heat the product. If the frequency of the microwave electromagnetic field exceeds 2450 MHz, for example 2650, this will cause it to burn.

Simultaneously with microwave heating, garlic is blown with air with an initial temperature of 293 K to remove water vapor evaporated from the product.

The choice of the initial air temperature of 293 K is due to the fact that air is taken from industrial premises, in which, as a rule, this temperature is maintained.

The use of air as a heat carrier with an initial temperature of more than 293 K, for example 303 K, will necessitate the installation of a heater for additional heating of the air, which may impair the quality of the finished product due to its overheating, increase the cost of production and increase the amount of capital investment due to the installation of additional equipment (heater).

The use of air as a heat carrier with an initial temperature of less than 293 K, for example 283 K, will necessitate the installation of cooling devices for additional air cooling, which during microwave drying can cause unnecessary excessive cooling of the product and lead to an increase in energy consumption and an increase in the cost of production.

The essence of the choice of stepwise modes of combined microwave convective drying of garlic is to divide the drying process into three stages of different duration, each of which, depending on the law of change in the current humidity of garlic, selects its own rational technological drying mode, i.e., the temperature of heating of the garlic plates with microwave the electromagnetic field and their airflow with the velocity of the coolant (air flow with an initial temperature of 293 K) took fixed values, the values of which are determined elyalis experimentally. Moreover, their selection at each stage must be carried out in accordance with the restrictions imposed by technological requirements on the quality of the finished product.

At the first time stage, chopped 3 mm thick garlic plates are heated by a microwave field to a temperature of 300 K while blowing air at a speed of 0.9 m / s for 7.5 minutes (Fig. 1). In this case, physicomechanical moisture is removed, i.e., moisture of micro- and macrocapillaries and wetting moisture. The main parameter affecting the intensity of moisture removal during this period is the coolant speed. Therefore, it is most advisable to use drying at the initial moment of drying with a high coolant velocity and a low heating temperature of the product. Drying at the first stage most fully meets this requirement.

Heating the product to a lower temperature than 300 K, for example 295 K, will reduce the evaporation efficiency of physico-mechanical moisture. Heating the product to a higher temperature than 300 K, for example 305 K, will lead to excessive overheating of the product and a decrease in its quality due to the decomposition of valuable thermolabile substances (vitamins, monosugars, amino acids, etc.).

Blowing the product with an air stream at a speed of less than 0.9 m / s, for example 0.7 m / s, will reduce the efficiency of removal of evaporated water vapor, and therefore, reduce the efficiency of heat and mass transfer of the drying process. Blowing the product with an air stream at a speed greater than 0.9 m / s, for example 1.1 m / s, will lead to the drying out of the surface layers of garlic and the formation of a crust on the surface of the garlic, which makes it difficult to remove evaporated moisture.

The duration of the first time step (7.5 min) was determined experimentally by analyzing the obtained drying curves. Using a longer duration of the first time step, for example 9 minutes, will dry out the surface layers of garlic and make it difficult to remove the moisture contained in the central layers of garlic. Using a shorter duration of the first time step, for example 6 minutes, will result in the fact that not all physico-mechanical moisture will be removed from the garlic, which will entail an increase in the duration of the subsequent temporary drying steps and a deterioration in the quality of the dried dried garlic.

At the second time stage, the pre-dried garlic plates are heated with a microwave electromagnetic field to a temperature of 316 K while blowing air at a speed of 0.7 m / s for 12 minutes (Fig. 1). With the removal of physical and mechanical moisture, the velocity of the coolant, as a determining factor in the intensity of the process, loses its significance. Therefore, in the second stage, it is preferable to carry out drying at a decreasing speed and increasing temperature of the coolant. Due to the fact that the temperature as a factor determining the intensity of internal moisture transfer has the greatest influence on the removal rate of osmotic (intracellular) and polyadsorption moisture, the product is heated by a microwave electromagnetic field to a temperature of 316 K. Heating of the product to a lower temperature than 316 K, for example 310 K, will reduce the evaporation efficiency of osmotic and polyadsorption moisture. Heating the product to a higher temperature than 316 K, for example 322 K, will lead to excessive overheating of the product and a decrease in its quality due to the decomposition of valuable thermolabile substances (vitamins, monosugars, amino acids, etc.). Blowing the product with an air stream at a speed of less than 0.7 m / s, for example 0.4 m / s, will not ensure the complete removal of evaporated water vapor, and, therefore, will reduce the efficiency of heat and mass transfer of the drying process. Blowing the product with an air stream at a speed greater than 0.7 m / s, for example 1.0 m / s, will lead to the drying out of the surface layers of garlic and the formation of a crust on the surface of the garlic, which makes it difficult to remove evaporated moisture.

The duration of the second time step (12 min) was determined experimentally as a result of analysis of the obtained drying curves. Using a longer duration of the second time step, for example 17 minutes, will dry out the surface layers of garlic and make it difficult to remove the moisture contained in the central layers of garlic. Using a shorter duration of the second time step, for example 7 minutes, will result in the fact that not all osmotic and polyadsorption moisture will be removed from garlic, which will entail an increase in the duration of subsequent temporary drying steps and a deterioration in the quality of the finished product.

At the third time stage, the pre-dried garlic plates are heated with a microwave electromagnetic field to a temperature of 320 K while blowing with an air stream at a speed of 0.5 m / s for 20 minutes (Fig. 1). As the osmotic moisture is removed, the velocity of the coolant as a determining factor in the intensity of the process loses its significance. Due to the fact that the temperature is most influenced by the temperature as a factor determining the intensity of internal moisture transfer, the product is heated by a microwave field to a temperature of 320 K. Heating the product to a lower temperature than 320 K, for example 315 K, will reduce the evaporation efficiency of monoadsorption moisture. Heating the product to a higher temperature than 320 K, for example 325 K, will lead to excessive overheating of the product and a decrease in its quality of garlic due to the decomposition of valuable thermolabile substances.

Blowing the product with an air stream at a speed of less than 0.5 m / s, for example 0.3 m / s, will not ensure the complete removal of evaporated water vapor, and therefore, will reduce the efficiency of heat and mass transfer of the drying process. Blowing the product with an air stream at a speed greater than 0.5 m / s, for example 0.7 m / s, will lead to the drying out of the surface layers of garlic and the formation of a crust on the surface of the garlic, which makes it difficult to remove evaporated moisture.

The duration of the third time step (20 min) was determined experimentally as a result of the analysis of the obtained drying curves. Using a longer duration of the third time step, for example 25 minutes, will dry out the surface layers of garlic and make it difficult to remove the moisture contained in the central layers of garlic. Using a shorter duration of the third time step, for example 15 minutes, will result in the fact that not all monoadsorption moisture will be removed from the garlic, which will entail an increase in the duration of subsequent temporary drying steps and a deterioration in the quality of dried garlic.

Adapted in accordance with the basic kinetic laws of the drying process, the coolant supply at the three stages of drying the product allows you to choose rational drying modes taking into account changes in the moisture content of the product during the drying process.

Then, dried on a final moisture content of 8%, the garlic plate is ground.

The table shows the chemical composition of fresh garlic and garlic dried according to the proposed three-stage regime of combined microwave convective drying.

A method for the production of dried garlic is illustrated by the following example.

Garlic is served in a washer, then washed garlic enters the conveyor belt with knives to trim the ends and lobes of garlic.

Table

The chemical composition of fresh garlic and dried garlic

 the proposed three-stage drying method

After trimming, the garlic is fed into the machine for dividing the garlic into cloves with rubberized rolls with a rough surface. Then garlic, divided into teeth, is fed to a sorting conveyor, where it is inspected and fed by an elevator to an air-cleaning machine, in which it is peeled. Next, the garlic is cut into plates with a thickness of 3 mm. Then chopped garlic plates are subjected to combined microwave convective drying. Moreover, the heating of the garlic is carried out by a microwave field with a frequency of 2450 MHz with simultaneous convective air blowing with an initial temperature of 293 K in three time stages. Simultaneously with microwave heating, the garlic is blown with air with an initial temperature of 293 K to remove water vapor evaporated from the product.

Dried garlic is served in a crusher, then in a roller machine for more thorough grinding. Thoroughly ground garlic enters the sifter, and from there to the packaging machine.

At the first time stage, chopped 3 mm thick garlic plates are heated by a microwave field to a temperature of 300 K while blowing air at a speed of 0.9 m / s for 7.5 minutes. In this case, physicomechanical moisture is removed, i.e., moisture of micro- and macrocapillaries and wetting moisture.

At the second time stage, the pre-dried garlic plates are heated by a microwave field to a temperature of 316 K while simultaneously being blown with an air stream at a speed of 0.7 m / s for 12 minutes. In this case, osmotic (intracellular) and polyadsorption moisture is removed.

At the third time stage, the pre-dried garlic plates are heated by a microwave field to a temperature of 320 K while blowing air at a speed of 0.5 m / s for 20 minutes. At the same time, monoadsorption moisture is removed from garlic.

Then, dried on a final moisture content of 8%, the garlic plate is ground. Dried garlic was analyzed. The analysis data are presented in the table "The chemical composition of fresh garlic and garlic dried by the proposed three-stage drying method."

Analysis of the data given in the table shows that dried garlic has a high content of valuable nutrient thermolabile substances. This indicates the correct choice of soft, gentle temperature-hydrodynamic drying regimes.

Such processing of garlic can increase the energy efficiency of the process, reduce the drying time of garlic and improve its quality.

Thus, the use of the proposed method for the production of dried garlic allows you to:

- receive high quality garlic with a high content of valuable thermolabile substances (vitamins, monosugar, amino acids, etc.);

- increase the thermal efficiency of the process;

- reduce energy and labor costs for the production of dried garlic due to the use of stepwise modes of combined microwave convective drying.

Claims (1)

A method for the production of dried garlic, including washing, trimming the ends and lobes of garlic, separating the garlic into cloves, sorting, pneumatic cleaning, drying, grinding, sieving, packaging and packaging of the finished product, characterized in that the garlic, cut into 3 mm thick plates, is subjected to a combined microwave -convective drying, which is carried out by exposing the product to a microwave electromagnetic field with a frequency of 2450 MHz and convective air blowing with an initial temperature of 293 K in three time stages: at the first stage Lastin garlic heated microwave waves to a temperature of 300 K, while blowing air stream with a velocity of 0.9 m / s for 7.5 min; in the second stage, up to a temperature of 316 K and an air flow rate of 0.7 m / s for 12 minutes; in the third stage, up to a temperature of 320 K and an air flow velocity of 0.5 m / s for 20 minutes.