RU2375931C2 - Production method of dried juice - Google Patents

Abstract

FIELD: food industry.

SUBSTANCE: invention is implemented by following: natural juice is warmed up Vapour is evaporated, drawoffed and condensed. Condensate is removed, paste is produced. The paste is dried at atmosphere pressure and temperature not exceeding 50°C till viscosity 20-200 Pa·s is obtained.

EFFECT: extraction of paste with granule production, drying of granulated juice till moisture content 6-14%.

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Description

The invention relates to the food industry, and in particular to technological processes for the production of dry juices.

A known method of condensation of water vapor from a drying device in a fluid flowing through a vacuum pump [1]. However, this method does not allow to obtain a vacuum (10-5 Pa), necessary to ensure a low-temperature (less than 50 ° C) boiling mode of the evaporated juice and preservation of the biological activity of the final product.

The closest technical solution, selected as a prototype, is a method for the production of dry juice, including freezing and freeze-drying of natural juice, followed by grinding the dried product into powder [2].

However, freeze-drying is associated with significant temperature changes in the product. When freezing, the temperature of the juice is lowered by 58 ° C from room temperature to minus 38 ° C. In the process of sublimation, the temperature of the juice is increased by 98 ° C from minus 38 ° C to plus 60 ° C. The total temperature drop of the juice in the process of freeze-drying is large and amounts to 156 ° C. In addition, the powdered juice obtained by freeze-drying has an extremely large surface of interaction with atmospheric oxygen, which leads to a rapid loss of properties during long-term storage of juice.

The problem to which the invention is directed, is to reduce the temperature range of natural juice during its processing to obtain granular juice.

This is achieved by the fact that in the method of producing dry juice, natural juice is heated, evaporated, steam is removed and condensed, condensate is removed to obtain a paste, the paste is dried at atmospheric pressure and a temperature not exceeding 50 ° C, until the viscosity for extrusion is reached 20-200 Pa · s, the paste is extruded to obtain granules and the granular juice is dried until a moisture content of 6-14% is reached.

Heating of natural juice, evaporation, removal and condensation of steam, removal of condensate to obtain a paste is carried out in vacuum at a vacuum (5-10) Pa and a temperature of up to 50 ° C. The vacuum (5-10) Pa provides high rates of moisture removal from the juice at low temperatures. Temperature up to 50 ° С allows preserving biologically active substances of the evaporated product. With vacuum evaporation, the temperature of the juice rises by no more than 30 ° C from room temperature to no more than plus 50 ° C. The temperature difference does not exceed 30 ° C and is less than the difference of 156 ° C, characterizing freeze-drying, not less than 5.2 times.

Reducing the temperature range of the processed juice with a multiplicity of 5.2 or more provides a proportional reduction in energy costs for obtaining dry juice.

The paste obtained by vacuum evaporation of natural juice, dried at atmospheric pressure and a temperature not exceeding 50 ° C, until the viscosity for extrusion of 20-200 Pa · s. This operation provides the preparation of pasty juice for granulation.

Extrusion allows the formation of granular juice from a sufficiently moist and viscous pasty juice.

Drying granular juice to a moisture content of 6-14%, which is carried out at a temperature not exceeding 50 ° C, is the final operation for obtaining dry juice. Granular juice, which has a significantly lower surface of interaction with atmospheric oxygen than powdered juice, provides unchanged properties during prolonged storage of juice under ordinary conditions at room temperature.

The test of the method was carried out using a small-sized device to remove moisture in a vacuum, allowing to evaporate natural juices at a vacuum (5-10) Pa and a temperature of up to 50 ° C [3].

Example 1. According to the claimed method, tests were carried out on 17 kg of natural blackcurrant juice with a moisture content of 83%. Using a foreline pump, a vacuum of 6 Pa was created in the system. After 30 minutes of heating, the process of evaporation of the juice reached a steady state. In the steady state, evaporation occurred at a temperature of 32 ° C. The temperature difference during the evaporation of the juice was 12 ° C, which is 13 times less than the difference during freeze-drying. After vacuum evaporation, which lasted three and a half hours, was obtained 8.7 kg of concentrated juice in the form of a paste with a moisture content of 67%. The paste was dried at atmospheric pressure and a temperature not exceeding 50 ° C until a viscosity of (20-100) Pa · s was reached, sufficient for extrusion. After four days of drying, the viscosity was 37.2 Pa · s, and the paste was extruded to obtain granules. The granular juice was dried for three days at a temperature not exceeding 50 ° C until a moisture content of (6-14)% was reached, which ensures long-term storage of granular juice under ordinary conditions at room temperature. The result is 3.2 kg of dry granulated blackcurrant juice with a moisture content of 11%.

Example 2. Tests were carried out on 22.5 kg of juice directly pressed gooseberries with a solids content of 14%. Evaporation was carried out in vacuum at a vacuum of 6 Pa and a temperature of up to 50 ° C. The temperature difference during the evaporation of the juice was 30 ° C, which is 5.2 times less than the difference during freeze-drying. At the end of vacuum evaporation, 9.2 kg of concentrated paste-like juice with a moisture content of 72% were obtained. The paste was dried at atmospheric pressure and a temperature not exceeding 50 ° C. At the end of the five-day drying, the viscosity was 98.1 Pa · s and the paste was extruded. The granular juice was dried for three days at a temperature not exceeding 50 ° C, to obtain 3 kg of dry granulated gooseberry juice with a moisture content of 13.6%.

Example 3. Tests were carried out on 25 kg of cranberry juice with a solids content of 11%. The juice was evaporated at a vacuum of 6 Pa and a temperature of up to 50 ° C. The temperature difference was 30 ° C, which is 5.2 times less than the difference during sublimation. At the end of evaporation, 9.7 kg of paste-like juice with a moisture content of 71.6% was obtained. The paste was dried at atmospheric pressure and a temperature not exceeding 50 ° C. After three days of drying, the viscosity was 21.6 Pa · s and the paste was extruded. The granular juice was dried for four days at a temperature not exceeding 50 ° C, to obtain 2.8 kg of dry granulated cranberry juice with a moisture content of 6.2%.

Example 4. Tests were performed on 19 kg of squeezed squeezed juice with a solids content of 12%. The juice was evaporated at a pressure of 5.5 Pa and a temperature of up to 40 ° C. The temperature difference during the evaporation of the juice was 20 ° C, which is 7.8 times less than the difference during sublimation. At the end of evaporation, 5 kg of concentrated paste-like juice with a moisture content of 55% was obtained. The paste was dried at atmospheric pressure and a temperature not exceeding 50 ° C. After five days of drying, the viscosity was 84 Pa · s and the paste was extruded. The granular juice was dried for four days to obtain 2.5 kg of dry granular pumpkin juice with a moisture content of 12.2%.

This method allows to reduce the temperature range of natural juice during its processing from 5.2 to 13 times with obtaining dry granulated juice.

TABLE PROPERTIES OF DRY GRANULATED JUICES Name Solids,% Ascorbic acid, mg% Organic acids,% Alimentary fiber, % Black currant 89 300 68 13,4 Gooseberry 86 53 16 8.3 Cranberry 94 35 80 12.3 Pumpkin 88 31 1.7 14.1

Information sources

1. Application EP No. 0240793, CL A26B 7/00, 1987.

2. Patent RU 2136182. Cl. A23L 2/14, A23B 7/024, 1999 (prototype).

3. Patent RU 2276314. Cl. A26B 5/04. 2006.

Claims (1)

A method for producing dry juice, including heating natural juice, evaporating, removing and condensing steam, removing condensate to obtain a paste, drying the paste at atmospheric pressure and a temperature not exceeding 50 ° C, until the viscosity for extrusion reaches 20-200 Pa · s, extruding the paste to obtain granules and drying the granulated juice to achieve a moisture content of 6-14%.