RU2574679C2 - Food products vacuum drying method - Google Patents

Abstract

FIELD: food industry.

SUBSTANCE: milled food product (in a 5-30 mm thick layer) is put into a vacuum chamber. Infrared lamps are installed in the vacuum chamber at a distance of 10-15 cm from the product. A residual pressure of (700-900) Pa is created. The product is heated up to 30-45°C with heat flux density equal to 15.0-20.0 kW/m². The product is dried during 2-3 hours till the product moisture weight fraction is no more than 4.0%.

EFFECT: invention allows to manufacture high quality dry products due to efficient distance from the infrared lamp to the product, which ensures the whole product area drying, as well as due to temperature, heat flux density and residual pressure values; additionally, the invention allows to reduce the process duration and significantly decrease specific heat expenditures.

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Description

The invention relates to the food industry, namely to the production of dry food products.

A known method of producing dry cheese in the form of granules, comprising freezing cheese at a temperature of minus 18-28 ° C for 12-24 hours, pre-grinding cheese into granules with a size of 3-5 mm, drying in a fluidized bed at a coolant temperature of 130-140 ° C with simultaneous grinding of cheese to powder [1].

The disadvantages of this method are the low quality of the process due to the large energy costs for freezing cheese; high drying temperature, which leads to protein degradation and a decrease in organoleptic and rheological parameters.

A known method of vacuum drying food products with a residual pressure of 4-8 kPa by heating food products in a sealed chamber with infrared radiation pulses up to 30-50 ° C with stirring, followed by condensation of water vapor by a water cooling system [2].

The disadvantages of this analogue are the relatively large energy costs due to the duration of the drying process and the low quality of the dried products due to not taking into account the magnitude of the heat load and the state in which the product enters the dryer.

The closest to implementation and the result obtained is a vacuum drying method, including grinding and drying at a positive temperature and residual pressure [3].

The disadvantage of the prototype is the high energy intensity, the duration of the process due to the use of residual pressure above 1000 PA. When drying pieces of cheese of relatively large sizes over 50 mm, uneven drying occurs, the surface layers dry out, and the thickness remains under-dried.

The basis of the invention is the creation of vacuum drying technology for food products having high quality indicators with a reduced duration of the drying process and low energy costs through the use of residual pressure below 1000 Pa and the rational arrangement of infrared lamps.

The task is achieved in that the product is crushed into a pallet with a layer thickness of 5 to 30 mm. After that, infrared lamps are installed at a rational distance of 10-15 cm so that the rays fall on the entire surface of the product. In the course of experimental data, it was found that at a distance of more than 15 cm, the angle of dispersion of the rays becomes not rational and leads to a loss of power, at a distance of less than 10 cm, the angle of dispersion does not cover the entire product area, which leads to increased drying of the product in the center of the pallet. Then the product is subjected to vacuum drying at a residual pressure of 700-900 Pa. Drying temperature is between 30-45 ° C. The heat to the dried product is supplied by infrared lamps at a heat flux density of 15.0-20.0 kW / m ² .

The duration of the drying process, depending on the type of food product, the thickness of the drying layer, the shape and size of grinding, the temperature in the drying chamber, the distance of infrared lamps, the heat load and the residual pressure is 2-3 hours, the mass fraction of moisture in the dry product is not more than 4, 0%

The method was carried out as follows. The food product was ground to the desired shape and size. Grinding was carried out in a pan, achieving the required layer thickness. Then the product tray was installed in a vacuum chamber, where it was dried for a certain time at the required temperature, the distance of infrared lamps from the product, heat flux density and residual pressure.

Examples of the method.

Example 1. They took carrots, chopped in the form of rectangles 5 × 5 × 5 mm in size. Grinding was carried out in a pan, the layer thickness was set equal to 15 mm Infrared lamps were installed at a distance of 13 cm. Then, the tray with carrots was placed in a vacuum chamber, where it was dried at a temperature of 40 ° C, a heat flux density of 15.0 kW / m ² and a pressure of 800 Pa. The drying time was 2.2 hours; the mass fraction of moisture in dry carrots was 4.0%.

Dry carrots have the appearance of rectangles of the same shape, easily scattering when squeezed. Characteristics of dry carrots: color - light red; taste and smell - carrots; the structure is porous.

Example 2. Take boiled lamb, chopped in the form of rectangles with a size of 30 × 20 × 20 mm Grinding was carried out in a pan, the layer thickness was set equal to 30 mm Infrared lamps were installed at a distance of 15 cm. Then the pan with boiled lamb was placed in a vacuum chamber, where it was dried at a temperature of 45 ° C, a heat flux density of 20.0 kW / m ² and a pressure of 900 Pa. The drying time was 2.7 hours, the mass fraction of moisture in dry mutton was 3.7%.

Dry mutton has the appearance of rectangles of the same shape, easily scattering when squeezed. Characteristics of dry mutton: color - light brown; taste and smell - lamb; the structure is porous.

Sources of literature

1. Patent No. 2039447 Russian Federation, A23C 19/086. A method of obtaining dry cheese / Kutsakova V.E., Khutieva E.S. - St. Petersburg Technological Institute of Refrigeration Industry. - No. 5060299/13; declared 08/26/1992; publ. 07/20/1995. (analog)

2. Patent No. 2279020 Russian Federation, IPC ⁷ F26B 5/04. The method of vacuum drying of food products / Popov AM, Belokurov A.G., Popov A.A. - KemTIPP. - No. 2004133432/13; declared 11/16/2004; publ. 06/27/2006 (analog).

3. Patent No. 2426462. The method of vacuum drying / A.Yu. Prosekov, V.A. Ermolaev, S.A. Ivanova; applicant GOU VPO Kemerovo Technological Institute of the Food Industry. - No. 2010017878; declared 03.03.2010; publ. 08/20/2011, Bull. No. 23 (prototype).

Claims (1)

Vacuum drying method, including grinding and drying at a positive temperature and residual pressure, characterized in that the food products are dried with a layer thickness of 5 to 30 mm at a residual pressure of 700-900 Pa, a temperature of 30-45 ° C, a heat flux density of 15.0 -20.0 kW / m ² , the distance from the infrared lamp to the product 10-15 cm, dried for 2-3 hours until the product reaches a mass fraction of moisture of not more than 4.0%.