RU2348333C1 - Method of manufacturing dried parsley roots - Google Patents

Abstract

FIELD: food production process.

SUBSTANCE: parsley roots are washed, inspected, alkaline cleaned, skinned. After alkaline is washed off parsley roots are washed and cut. After that drying is performed in three stages. At the first stage cut parsley roots are treated in dense layer by coolant flow at the temperature of 318 K and speed of 2.2 m/s during 12 minutes. At the second stage - at the temperature of 328 K and speed of 1.2 m/s during 38 minutes. At the third stage - at the temperature of 333 K and speed of 0.6 m/s during 45 minutes. Parsley roots are mixed under drying process in fluidised layer during 3.5 seconds.

EFFECT: finished product quality improvement and improvement of thermal effectiveness of drying process due to staged drying of parsnip roots in dense layer using fluidising for mixing.

1 tbl, 1 dwg, 1 ex

Description

The invention relates to a vegetable drying and food concentrate industry, namely the production of dried parsley roots, and can be used for the production of spices and seasonings.

A known method for the production of dried parsley roots, which includes washing in cam or drum machines (water to product ratio 3: 1), inspection (manually rotten roots with black spots and other defects are manually removed, the roots are cleaned of side roots), alkaline cleaning ( caustic soda solution with a concentration of 3 ... 6% at a temperature of 80 ... 85 ° C for 5 min), peeling and alkali washing in a washing and cleaning machine, manual tertiary treatment, cutting or on columns (shavings) with a section of 3 × 5 mm, length n less than 5 mm, or cubes with sides measuring 5 ... 9 mm or a plate is not more than 4 mm in thickness, length and width of 9 ... 12 mm), drying and inspection. Parsley roots are dried on five-belt conveyor dryers. The product enters the dryer, is laid out with the help of a stacker and moves along the conveyor belt, pouring from one belt to another. The initial drying temperature is 48 ... 50 ° C, the temperature in the middle sections of the dryer is 52 ... 55 ° C, at the final stage the temperature is 45 ... 40 ° C. Drying time 3.50 ... 4.13 hours. Humidity of the final product no more than 14% (in agreement with the consumer - with a mass fraction of moisture not more than 8%) [Handbook of the technologist of food-concentrate and vegetable-drying production / V.N. Gulyaev, N.V. .Dremina, Z.A. Katz and others; Ed. V.N. Gulyaev. - M .: Light and food industry, 1984. - 488 p., S. 330-332].

The disadvantages of this method is the significant energy consumption and low quality of the finished product and the duration of the drying process.

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 stepwise drying modes of parsley roots in a dense layer using fluidization for mixing, reducing energy consumption to obtain the finished product, and intensifying the drying process.

The problem is achieved in that in the proposed method for the production of dried parsley roots, including washing, inspection, alkaline cleaning, peeling and alkali washing, post-treatment, cutting, drying and inspection, new is that drying is carried out in three time stages: the first stage, chopped parsley roots are treated in a dense layer with a flow of coolant (air) with a temperature of 318 K and a speed of 2.2 m / s for 12 min; at the second stage - by the flow of coolant (air) with a temperature of 328 K and a speed of 1.2 m / s for 38 minutes; at the third stage - by the flow of coolant (air) with a temperature of 333 K and a speed of 0.6 m / s for 45 minutes; throughout the drying process, parsley roots are subjected to stirring in a fluidized bed for 3.5 s, and in the first stage, every 2.5 minutes; on the second - after 3.0 minutes; in the third - after 4.5 minutes.

The technical result consists in increasing the thermal efficiency and intensification of the drying process, improving the quality of the finished product through the use of stepwise drying modes of parsley roots in a dense layer using fluidization for mixing, in reducing the energy consumption for obtaining the finished product.

The drawing shows the kinetic dependences of the drying process of cubes of parsley roots with rational operating parameters: a - a diagram of the change in the velocity v and temperature T of the coolant over time, b - the drying curve W = f (τ) and the drying speed curve dW / dτ = f (W) parsley roots, where W is the moisture content of parsley roots,%, τ is the time, s; c - thermogram of the drying process of parsley roots T _n = f (τ), where T _n is the temperature of parsley roots.

Fresh parsley roots were used as an object of study. The color of the root of the parsley is grayish-white on the outside, white inside with a light yellow border.

The edged root crop of fresh parsley, which is being processed, must comply with the technical specifications of the PCT of the RSFSR 748-88 and meet the following requirements:

in appearance: the root crops are fresh, whole, healthy, unpolluted, the root crops are non-deciduous, ugly;

by the size of root crops, mm, not less: by the largest transverse diameter - 15;

the content of root crops with minor damage by pests, in% by weight, not more than: 5; damage by pests and rodents is not allowed;

root crops of less than the established size - less than 0.5 cm; for varieties of cylindrical shape - 15 mm; for cone-shaped varieties - 5 mm; slightly wilted - 5%; branched and ugly root crops - 5%; with incorrectly cut leaves - 5%;

by the presence of land adhered to root crops,% - 1.

The total number of tolerances without taking into account the tolerance of root crops in size should not exceed 15% by weight, and the tolerances for each indicator should not exceed the norms established for them.

The main nutritional value of parsley is a wealth of vitamins and essential oils. The dry matter content on wet weight in root crops is 11.6 ... 36.4%; sugar content - 2.9 ... 10.1% (of which more than half sucrose). Parsley root crops contain 85% water, 1.5% protein, 11.0% carbohydrates (including 9.4% mono- and disaccharides and 0.4% starch), the amount of fiber ranges from 1.4 to 2, organic acids - 0.1 ... 0.2% (in terms of apple) and 1.1% ash. Parsley root crops contain little fiber (1.3%) and a rich set of trace elements: potassium - 262; calcium - 86; magnesium - 41; phosphorus - 82; iron - 1.8 mg per 100 g of the edible part of the product. The roots of parsley contain vitamins: β-carotene - 0.01; B ₁ - 0.08; B ₂ - 0.10; PP - 1.00; C - 35 mg per 100 g of the edible part of the product. The energy value of parsley root crops is 47 kcal / 100 g [Handbook of the technologist of food-concentrate and vegetable-drying production / V.N. Gulyaev, N.V. Dremina, Z.A. Kats and others; Ed. V.N. Gulyaev. - M .: Light and food industry, 1984. - 488 p., S. 307-308]. Among other spicy crops, parsley stands out for its high content of nitrogenous substances (N × 6.25): up to 3.2% in root crops.

Essential oils cause a characteristic smell of the plant. Parsley root vegetables contain 0.02 ... 0.05% oils. The most important component of the oil (50%) is phenolic ether or apiol. Of other compounds, alkaloids and glucosides accumulate, as well as apinene (5%), meristidine, isomeristicin, palmitic and stearic acids, phenols, aldehydes and ketones, and petrozylan hydrocarbon. Oils have a high content of unsaturated acids: palmitic, oleic, linoleic and especially petrozelipic.

Parsley roots contain a significant amount of ascorbic acid, carotene, vitamins B ₁ , B ₂ , K, PP, folic acid, potassium, magnesium, iron, inulin, flavonoids, glycosides, therefore it is recommended for vitamin deficiency, anemia. A large amount of potassium in parsley makes it valuable for diseases of the cardiovascular system, as well as for diabetes.

Parsley roots are used for kidney diseases and inflammation of the bladder and as a lung laxative. Seeds and essences obtained from the plant are strong diuretics. Leaves are used to treat wounds, apply them to places of insect bites to reduce inflammation and pain. Parsley has a pleasant aroma, has a sweet, spicy and slightly bitter taste, due to the presence of essential oil. Among spicy vegetables, it occupies a leading position. Parsley is used in the conservation of tomatoes, cucumbers, squash, zucchini, eggplant, cooking tomato sauces and other long-term home products.

In industry, parsley is one of the main components of dry spicy mixtures, which are used for the preparation of soup concentrates. It is used in the canning industry, in the production of ketchups, etc.

In cooking, parsley is used as an independent snack and added to salads, cold meat and fish dishes, soups, okroshka, main dishes of meat, fish, poultry, game, offal, vegetables, eggs, cereals, and flour products. It is flavored with sauces, gravy, fillings, pastes, seafood, cheeses and cottage cheese, sweet dishes, such as jelly. Essential oil, seeds, roots, dried and fresh herbs are used as part of spicy mixtures.

A method of manufacturing dried parsley roots is as follows.

Parsley roots are washed in a drum washer with a hydromodule 3: 1. After this, they are inspected: rotten roots with black spots and other defects are manually selected, while the roots are cleaned of side roots.

Then the parsley roots are subjected to cleaning. Peeling can be done mechanically or using an alkaline solution. The essence of the alkaline method is to treat the roots of parsley with a solution of caustic soda with a concentration of 3 ... 6% at a temperature of 80 ... 85 ° C for 5 minutes, remove the skin and wash off the alkali in a washing and cleaning machine. Losses during cleaning, depending on the method of peeling and the quality of raw materials, range from 6 to 17%. Then the parsley roots are manually cleaned.

Parsley roots are cut either into columns (shavings) with a section of 3 × 5 mm, a length of at least 5 mm, or into cubes with a face size of 5 ... 9 mm, or onto plates (flakes) with a thickness of not more than 4 mm, length and width 9 ... 12 mm Parsley roots treated in this way are placed in the working chamber of the dryer and dried in three time steps (see drawing, a).

At the first stage, chopped parsley roots are treated in a dense layer with a flow of heat carrier (air) with a temperature of 318 K and a speed of 2.2 m / s for 12 minutes.

At the second stage, parsley roots are treated in a dense layer with a flow of coolant (air) with a temperature of 328 K and a speed of 1.2 m / s for 38 minutes.

At the third stage, parsley roots are treated in a dense layer with a coolant (air) flow with a temperature of 333 K and a speed of 0.6 m / s for 45 minutes.

Throughout the entire drying process, parsley roots are mixed in a fluidized bed for 3.5 s, with the first step every 2.5 minutes; on the second - after 3.0 minutes; in the third - after 4.5 minutes. Using air-mixing allows more uniform drying of parsley roots.

The following approach is proposed to justify the choice of stepwise modes of drying parsley roots. Its essence lies in dividing the drying process into three stages of different duration, at each of which, depending on the law of change in the current humidity of parsley, its rational technological mode of drying is selected, i.e. The temperature and velocity of the coolant assumed fixed values, the values of which were determined 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.

Such a three-stage heat supply mode, i.e. the alternation of temperature and hydrodynamic processing in a dense layer and a change in the duration of the stages is due to the following. At the beginning of the drying process, mechanically bound moisture is removed, i.e. moisture of microcapillaries, macrocapillaries and wetting. 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 a high speed and low temperature at the initial moment of drying. The technological modes of drying at the first stage most fully meet these requirements.

As the indicated moisture is removed, the velocity of the coolant, as a determining factor in the intensity of the process, loses its significance. With further drying, osmotic, poly- and monoadsorption moisture is removed, the removal rate of which is most affected by the temperature of the coolant, since only the temperature of the coolant determines the intensity of internal moisture transfer. Therefore, in the second and third stages, drying is preferable to carry out at a decreasing speed and increasing temperature of the coolant. Thus, if at the beginning of the process the drying speed is mainly limited by the coolant speed, then by its temperature. This leads to a change in the ratio of the durations of the drying stages.

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.

Parsley roots are dried to a final moisture content of the finished product of 14%. Such treatment of parsley roots can improve the energy efficiency of the process, reduce the drying time of parsley and improve its quality.

A method of manufacturing dried parsley roots is illustrated by the following example.

An example implementation of a method for the production of dried parsley roots. Initially, parsley roots are subjected to friction (mechanical) cleaning for 0.5 min to remove large contaminants and solid "outgrowths" from their surface. Then the roots of the parsley are washed in a drum washer with a hydromodule 3: 1. After this, they are inspected: rotten roots with black spots and other defects are manually selected, while the roots are cleaned of side roots.

Then the parsley roots are subjected to cleaning. Peeling can be done mechanically or alkaline. The essence of the alkaline method is to treat the roots of parsley with a solution of caustic soda with a concentration of 3 ... 6% at a temperature of 80 ... 85 ° C for 5 minutes, remove the skin and wash off the alkali in a washing and cleaning machine. Losses during cleaning, depending on the method of peeling and the quality of raw materials, range from 6 to 17%. Then the parsley roots are manually cleaned.

Parsley roots are cut into cubes with a face size of 5 ... 9 mm and placed in the working chamber of the dryer and dried in three time steps (see drawing, a).

At the first stage, chopped parsley roots are treated in a dense layer with a flow of heat carrier (air) with a temperature of 318 K and a speed of 2.2 m / s for 12 minutes. At the beginning of the drying process, mechanically bound moisture is removed, i.e. moisture of microcapillaries, macrocapillaries and wetting.

The technological parameters of the coolant (temperature 318 K and speed 2.2 m / s) and the duration of the first stage (12 min) are interrelated and their choice is due to the fact that they are complexly aimed at removing mainly mechanically bound moisture, the evaporation of which dominates at the beginning of the drying process. The main parameter affecting the intensity of moisture removal during this period is the coolant speed. Therefore, it is most expedient to use drying at the initial moment of drying at a high speed (2.2 m / s) and low temperature (318 K).

The use of a coolant velocity of less than 2.2 m / s, for example 2.0 m / s, will reduce the hydrodynamic effect of tearing the liquid film from the surface of the product and, as a result, reduce the evaporation efficiency.

The use of a coolant velocity of more than 2.2 m / s, for example 2.7 m / s, will lead to the soaring or even entrainment of parsley root particles, which will cause increased energy consumption during fan operation.

The use of a coolant with a temperature of less than 318 K, for example 312 K, will lead to insufficiently rapid heating of the liquid film and, as a result, to a decrease in the efficiency of its evaporation.

The use of a coolant with a temperature of more than 318 K, for example 323 K, will lead to increased energy consumption and incomplete use of the energy potential of the coolant.

An analysis of the drying curves and the drying speed of parsley roots (see drawing, b) shows that there are three periods: heating, constant and decreasing drying speeds. Analysis of the drying curve of parsley roots (see drawing, b) shows that the duration of the warm-up period is very significant and amounts to 11.5 ... 12.0 min. It is with this consideration that the choice of the duration of the first stage is justified - 12.0 minutes.

With a shorter duration of the first stage, for example 9 min, mechanically bound moisture did not have time to completely evaporate, and the cubes of parsley roots tended to stick together and clump. With a longer duration of the first stage, for example, 14 min, mechanically bound moisture completely evaporated, and further heat supply was not rational from an energy point of view.

At the second stage, parsley roots are treated in a dense layer with a flow of coolant (air) with a temperature of 328 K and a speed of 1.2 m / s for 38 minutes. The technological parameters of the coolant (temperature 328 K and speed 1.2 m / s) and the duration of the second stage (38 min) are interrelated, and their choice is due to the fact that they are complexly aimed at removing osmotically and polyadsorption bound moisture. For intensive removal of osmotically and polyadsorption bound moisture, it is advisable to increase the temperature of the coolant and reduce its speed. Therefore, it is most advisable to use a coolant at a speed of 1.2 m / s and a temperature of 328 K.

The use of a coolant with a speed of less than 1.2 m / s, for example 0.9 m / s, will lead to a decrease in the evaporation efficiency of osmotically and polyadsorption bound moisture.

The use of a heat carrier with a speed of more than 1.2 m / s, for example 1.4 m / s, will cause the heat carrier to be in contact with the parsley root particles for a short time and not have time to give up its heat to them: this will cause increased energy consumption for the drying process .

The use of a coolant with a temperature of less than 328 K, for example 323 K, will lead to insufficiently fast heating of parsley root particles and, as a result, to a decrease in the evaporation efficiency.

The use of a coolant with a temperature of more than 328 K, for example 332 K, will lead to increased energy consumption and incomplete use of the energy potential of the coolant.

An analysis of the drying curve of parsley roots (see drawing, b) shows that the duration of removal of osmotically and polyadsorption bound moisture is 38 min. It is this consideration that justifies the choice of the duration of the second stage - 38 minutes.

With a shorter duration of the second stage, for example 34 minutes, the osmotically and polyadsorption bound moisture did not have time to completely evaporate. With a longer duration of the second stage, for example, 44 min, the osmotically and polyadsorption bound moisture completely evaporated, and further heat supply was not rational from an energy point of view.

At the third stage, parsley roots are treated in a dense layer with a coolant (air) flow with a temperature of 333 K and a speed of 0.6 m / s for 45 minutes. The technological parameters of the coolant (temperature 333 K and speed 0.6 m / s) and the duration of the third stage (45 min) are interrelated, and their choice is due to the fact that they are complexly aimed at removing mainly monoadsorption bound moisture. For intensive removal of monoadsorption bound moisture, it is advisable to increase the temperature of the coolant and reduce its speed. Therefore, it is most advisable to use a coolant at a speed of 0.6 m / s and a temperature of 333 K.

The use of a coolant with a speed of less than 0.6 m / s, for example 0.3 m / s, will reduce the efficiency of evaporation of monoadsorption bound moisture.

The use of a heat carrier with a speed of more than 0.6 m / s, for example 0.9 m / s, will lead to the fact that the heat carrier has been in contact with the parsley root particles for a short time and does not have time to give up its heat to them: this will cause increased energy consumption for the process drying.

The use of a coolant with a temperature of less than 333 K, for example 327 K, will lead to insufficiently fast heating of parsley root particles and, as a result, to a decrease in the evaporation efficiency.

The use of a coolant with a temperature of more than 333 K, for example 338 K, will lead to increased energy consumption and incomplete use of the energy potential of the coolant.

Analysis of the drying curve of parsley roots (see drawing, b) shows that the duration of removal of monoadsorption bound moisture is 45 minutes It is this consideration that justifies the choice of the duration of the third stage - 45 minutes.

With a shorter duration of the third stage, for example, 30 min, monoadsorption bound moisture did not have time to completely evaporate. With a longer duration of the third stage, for example, 50 min, monoadsorption bound moisture completely evaporated, and further heat supply was not rational from an energy point of view.

The choice of the hydrodynamic (high-speed) mode of drying parsley root cubes with air (at the first stage of drying, the coolant speed when drying in a dense layer is 2.2 m / s for 12 minutes, at the second stage - 1.2 m / s for 38 minutes; at the third stage - 0.6 m / s for 45 min) was experimentally selected and depended on the nature of the change in humidity of the parsley root cubes during drying. With drying, the moisture of the cubes of parsley roots decreased, their mass also became less. When drying the roots of parsley, shrinkage was observed, i.e. reducing the size of the cubes. Therefore, for uniform processing of cubes of parsley roots, an adjustable heat supply was required, which was ensured by this law of change in the coolant speed (see drawing, a, see type A, B and C). Failure to comply with this time and speed regimes led either to overdrying and burning of the parsley roots, or, conversely, to underdrying and obtaining a product with high humidity, which was a violation of the applicable specifications.

The temperature regime of drying the cubes of parsley roots was selected experimentally and depended on the nature of the change in moisture of the product during drying. With drying, the humidity of the cubes of parsley roots decreased, their temperature increased. In order for the temperature of the parsley roots not to exceed the maximum permissible temperature (above which the thermal decomposition of valuable nutrients was observed: melanoid formation, thermolysis, etc.), a gradual and controlled change in the temperature of the coolant was necessary to achieve uniform processing of the parsley root cubes. Failure to comply with this time and temperature conditions led either to overdrying and thermal decomposition of parsley roots, or, conversely, to underdrying and to obtain a product with high humidity, which was a violation of current technical conditions.

Throughout the entire drying process, parsley roots are mixed in a fluidized bed for 3.5 s, and in the first stage, every 2.5 minutes at a speed of 3.0 m / s; on the second - after 3.0 minutes at a speed of 2.7 m / s; in the third - after 4.5 minutes at a speed of 1.6 m / s (see drawing, a). The use of the above speeds at different stages of drying allows for uniform mixing in the fluidized bed. The values of these velocities (3.0 m / s, 2.7 m / s, 1.6 m / s) were established experimentally. In this case, the coolant flow turbulizes the product layer, mixes it and evens out the average moisture content of the parsley root particles along the volume of the layer. As a result of collisions of parsley root particles with stirring, gas layers are also disturbed and stagnant zones are eliminated. The use of a pseudo-boiling layer for mixing particles of parsley roots allows for more uniform drying. Using a mixing time of less than 3.5 s, for example 2 s, will not allow uniformly mixing the layer of parsley root particles. Using a mixing time of more than 3.5 s, for example 6 s, will lead to unnecessary, unnecessary energy consumption for mixing the layer of parsley root particles.

The use of a different time interval between stirring (2.5 minutes at the first stage of drying, then 3.0 minutes at the second stage of drying and 4.5 minutes at the third stage of drying) is due to the different rate of change in the adhesive properties of parsley roots. If, at the beginning of drying, the cubes of parsley roots stick together well due to high humidity, and they need to be mixed more often to prevent conglomeration, then, as the surface moisture evaporates, the stickiness of their surfaces decreases, so the need for unnecessarily frequent mixing disappears. Another argument in support of the proposed mixing time intervals is the different heating rates (see drawing, c) of the parsley root cubes: cubes located on the surface of the gas distribution grid, i.e. directly in contact with fresh coolant, and cubes of parsley roots located in the upper part of the layer. The difference between the temperatures of these layers decreases as drying and the need for frequent mixing also disappears. These time intervals were established experimentally.

Thus, the best option for drying parsley roots for all quality and energy indicators is the above method with the rationale for each parameter. This is due to the uniformity of drying throughout the volume of the parsley cubes and the intense evaporation of moisture from their surface. A reduction in the rate of internal heat transfer is achieved in comparison with the rate of movement of moisture and its evaporation from the surface of cubes of parsley root of this size.

In this case, the heating of the cubes of parsley roots occurs more slowly than moisture evaporates from them, which completely eliminates overheating of the product and ensures its high quality. From the energy point of view, the proposed option allows us to provide the most rational energy consumption per 1 kg of the obtained product, which is explained by the hydrodynamics of the process, which changes in time not only by pulsating changes in speed with alternating drying time intervals in a dense and fluidized bed, but also by the chosen equivalent particle size. In this case, the pressure drop in the product layer, corresponding to the mass and heat flow of the coolant for a given processing mode, provides minimal energy consumption for obtaining a quality product. The drying time of parsley roots is 95 minutes according to the proposed technology and 3.50 ... 4.13 hours according to the factory. The quality of the dried roots must meet the requirements of GOST 16731-71 “White roots of parsley, celery, dried parsnip”. They were investigated by organoleptic and physico-chemical indicators (see table).

Determination of these indicators allows you to identify structural changes in the dried roots of parsley occurring in the process of drying, and to assess the quality of the resulting product.

Evaluation of the effectiveness of the method of production of dried parsley roots according to the proposed and factory technology was carried out by the value of specific energy consumption per 1 kg of finished product.

The value of the specific energy consumption per 1 kg of dried parsley roots, prepared according to the factory technology, is 4850 kJ / kg. The value of specific energy consumption per 1 kg of dried parsley roots, prepared according to the proposed technology, is 4720 kJ / kg.

Thus, the above analysis shows the high thermal efficiency of the proposed technology for the production of dried parsley roots compared to the factory technology.

The proposed method for the production of dried parsley roots has the following advantages:

- a significant reduction in the drying time from 3.50 ... 4.13 h in the factory technology to 95 min in the proposed;

- obtaining dried parsley roots with a higher content of valuable nutrients (proteins, carbohydrates, etc.);

- a significant reduction in energy consumption for the process of drying the roots of parsley.

Claims (1)

A method for the production of dried parsley roots, including washing, inspection, alkaline cleaning, peeling and alkali washing, post-treatment, cutting, drying and inspection, characterized in that the drying is carried out in three time steps: at the first stage, the cut parsley roots are processed in a dense layer a coolant (air) flow with a temperature of 318 K and a speed of 2.2 m / s for 12 min; at the second stage - by the flow of coolant (air) with a temperature of 328 K and a speed of 1.2 m / s for 38 minutes; at the third stage - by the flow of coolant (air) with a temperature of 333 K and a speed of 0.6 m / s for 45 minutes; throughout the drying process, parsley roots are subjected to stirring in a fluidized bed for 3.5 s, and in the first stage, every 2.5 minutes; on the second - after 3.0 minutes; in the third - after 4.5 minutes.

Images