RU2608645C1 - Method for pulse moisture removal from products - Google Patents

Abstract

FIELD: food industry.

SUBSTANCE: invention relates to food industry. Method comprises drying products by alternation of cycles of evacuating to residual pressure of 25 kPa for 30 min and delivery of excess pressure 6÷7 kPa for 15 minutes. Product is heated to temperature of 50 °C with gaseous heat carrier during period of delivering excess pressure and with infrared lamps during evacuation period.

EFFECT: invention enables to reduce duration of moisture removal on average by 10÷15 %, wherein that type of drying is characterized by high quality dried product.

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Description

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

A known method of drying hard cheeses [1], which involves grinding cheese to a layer thickness of 10 ÷ 50 mm and vacuum dehydration in three stages: in the first stage, the residual pressure is 15 ÷ 16 kPa, and the heating temperature is 85 ÷ 90 ° C, in the second stage drying is carried out at a residual pressure of 7 ÷ 8 kPa and a temperature of 70 ÷ 75 ° C, in the third stage, the residual pressure is reduced to 2 ÷ 3 kPa, and the temperature is reduced to 55 ÷ 60 ° C. In this case, drying is carried out using infrared lamps at a heat load of 5 ÷ 9 kW / m ² .

A known method of multi-stage drying of brine cheeses [2], including grinding the product into various forms to a layer thickness of 100 mm and drying under vacuum in four stages: at the first stage, the heating temperature is 90 ÷ 100 ° C, the residual pressure is 20 ÷ 25 kPa, and the thermal load is 14 ÷ 15 kW / m ² . Over the next three stages of drying, the heating temperature decreases to 70 ÷ 80 ° C, 60 ÷ 70 ° C and 45 ÷ 55 ° C, respectively, the residual pressure drops to 15 ÷ 17 kPa, 10 ÷ 11 kPa and 7 ÷ 8 kPa, and the heat load decreases to 10 ÷ 11 kW / m ² , 7-8 kW / m ² and 4-5 kW / m ^2, respectively. Throughout the drying process, a mixing device with a rotation speed of 5 rpm is used.

The disadvantage of both drying methods is the destruction of thermolabile components of the product under the influence of high temperatures.

Closest to the technical solution to the proposed method is a method of drying materials of vegetable, animal origin, fish and seafood and a device for its implementation [3]. This method involves several thermal vacuum-pulse cycles, which include heating the product to a temperature that does not cause denaturation of its initial characteristics, high-speed pulse evacuation, holding after evacuation and venting to atmospheric pressure. In this case, the material is heated in the drying chamber and the vacuum is released by drained air or gas coolant at a temperature of 300 ° C.

The disadvantage of this method is the high energy consumption for heating the coolant.

The basis of the invention is the task of increasing the efficiency of vacuum drying of products by reducing the duration of the process while maintaining the quality of the product. The technical result is achieved due to the fact that drying is carried out by alternating cycles of evacuation and pumping overpressure, the duration of which is 30 and 15 minutes, respectively. The magnitude of the excess and residual pressure is 25 and 6 ÷ 7 kPa, respectively. In this case, the product is heated by a gaseous coolant (during the period of overpressure injection) and infrared lamps (during the evacuation period) to a temperature of not more than 50 ° C, which eliminates the negative effect of high temperatures on thermolabile components of food products. Drying in this way can be carried out with different thicknesses of the product layer and particle size.

Due to the exposure of the product under excess pressure, the product is quickly heated to a predetermined temperature due to the higher heat capacity of the drying agent and the resulting pressure gradient between the product and the environment after depressurization and evacuation of the working chamber. For example, the drying time of the Kostroma cheese in this way at a heating temperature of 50 ° C, a heat flux density of 6 kW / m ² , a drying layer thickness of 10 mm and grinding the product in the form of cubes of 10 × 10 × 10 mm is 230 minutes.

The claimed invention allows to reduce the duration of moisture removal by an average of 10 ÷ 15%, while this type of drying is characterized by low specific energy consumption and high quality of the dehydrated product.

Information sources

1. Patent No. 2413418, Russian Federation, IPC A23C 19/086. The method of drying hard cheeses / Ostroumov L.A., Prosekov A.Yu., Ermolaev V.A. - No. 2009140120/10; declared 10/29/2009; publ. 03/10/2011 (analog).

2. Patent No. 2423052, Russian Federation, IPC A23C 19/086. The method of multi-stage drying of brine cheeses / Prosekov A.Yu., Ermolaev V.A. - No. 2010016683/10; declared 02/24/2010; publ. 07/10/2011 (analog).

3. Patent No. 2395766, Russian Federation, IPC A23C 19/086. A method of drying materials of vegetable, animal origin, fish and seafood and a device for its implementation / Veselov V.M., Zalevsky V.M., Ermakova L.S., Tamurka V.G., Volodin BC, Hapaeva S.N., Evdokimov V.D. - No. 2009119415/06; declared 05/25/2009; publ. 07/27/2010 (prototype).

Claims (1)

The method of pulsed moisture removal from food products, characterized in that the product is heated to a temperature of 50 ° C, and characterized in that the drying proceeds by alternating vacuum cycles to a residual pressure of 25 kPa and pumping overpressure of 6 ÷ 7 kPa, the duration of which is respectively 30 and 15 minutes, while heating the product is carried out by a gaseous coolant during the period of overpressure and infrared lamps during the evacuation period.