RU2245084C1 - Method for manufacture of sublimated food products - Google Patents

Abstract

FIELD: food-processing industry.

SUBSTANCE: method involves forming basic product by extruding it immediately into sublimation chamber zone with pressure above triple point; providing evaporative freezing of product with pressure below triple point and sublimation drying thereof in superhigh frequency energy field, with following removal through sluice gate; providing additional extrusion of product through coaxial channel peripheral with respect to central channel; introducing product with increased content of dry substance via peripheral coaxial channel for further forming of slightly dried carcass of product; feeding product with low dry substance content via central channel.

EFFECT: improved quality of product and reduced power consumption.

2 cl, 2 dwg

Description

The present invention relates to the production of freeze-dried foods.

A known method of continuous freeze-drying of heat-sensitive materials (RF Patent 2187053. Cl. F 26 In 7/00, 08/10/2002), including the formation of granules and freezing of granules of capillary-porous material in vacuum, drying it in the field of infrared radiation to form a dry box , from granules with a dried outer surface, a layer is created with granules moving in it from top to bottom, which are constantly irradiated in the upper part of the layer with a microwave field, and the bottom of this layer of dried material is blown with a stream of inert gas, such as argon, while the pressure above the upper surface of the layer is maintained at a temperature corresponding to the saturation temperature of sublimating vapors equal to the minimum freezing temperature, the temperature in the layer at one third of the height from the upper surface does not exceed the cryoscopic temperature of the product, the temperature on the lower surface of the dried material layer is set in an inert gas stream not higher than the temperature, reducing its biological activity in the characteristic parameter at a residual pressure of water vapor corresponding to ioskopicheskoy freezing temperature of the material, and moving the granules in the layer changes between water vapor pressure between the upper and lower layer surface is left constant during the continuous drying material.

The disadvantage of this method is the use of additional inert gas (for example, argon) to create the necessary residual pressure, as well as the use of an infrared radiation field to form a dry box of granules with a dried outer surface, which leads to high energy costs and an increase in the cost of the product.

The closest in technical essence and the achieved effect to the proposed one is a method for producing sublimated food products (Patent of the Russian Federation 2197874. Cl. A 23 L 3/44, 02/10/2003. Bull. No. 4), including molding the original product by extrusion by extrusion directly into a sublimation chamber into a zone with a pressure above a triple point due to its simultaneous treatment with steam under a pressure above a triple point with the formation of a highly developed uniformly distributed porous structure, evaporative freezing of the product in not a pressure below the triple point and freeze drying in the field of microwave energy, followed by removal through the rotary valve, wherein the steam to form a gate area with a pressure above triple point is created by the vapor formed as a result of intensive evaporation of moisture in the feeding zone product.

The disadvantage of this method is the inability to provide a product with desired properties and to dry a product with a low dry matter content as a result of its boiling, spraying and obtaining an uncertain shape and size, which leads to an increase in energy consumption and a decrease in quality during its processing.

An object of the invention is to obtain a product with desired properties, the possibility of drying a product with a low dry matter content and improving the quality of the finished product, reducing energy costs for its production.

The problem is achieved in that in a method for producing sublimated food products, including molding the starting product by extrusion by extruding it through the central channel of the extruder directly into the sublimation chamber into an area with a pressure above the triple point created by the steam shutter from vapors formed as a result of intense evaporation of moisture in the product supply zone to obtain a highly developed uniformly distributed porous structure, evaporative freezing of the product in the zone pressure below the triple point and freeze-drying it in the microwave energy field with subsequent removal through the lock gate, it is new that the product is additionally extruded through a coaxial peripheral channel with respect to the central channel, while a dry product is introduced through the coaxial peripheral channel substances of 30-50% or with a high content of fat or sugar with the subsequent formation of a dried-up skeleton of the product due to the intensive evaporation of moisture from it under the action of at a residual pressure of 611-620 Pa, and through the central channel, a product having a solids content of 3-10% is fed into this frame.

The technical result consists in obtaining a product with desired properties and in the possibility of drying the product with a low dry matter content with high quality and low energy consumption.

Figure 1 presents a General view of the installation for implementing the method of producing sublimated food products, figure 2 - extruder and a diagram of the formation of the structure of the product when it is extruded directly into the sublimation chamber in a zone with a pressure above the triple point.

The installation (figure 1, 2) for implementing the method of producing freeze-dried food products consists of a vacuum sublimation chamber 1 with a vertically arranged extruder 2 for feeding a product into it, which has a central channel 3, where the injection screw 4 is coaxially mounted for rotation from the drive (not shown). In this case, the central channel 3 is limited by the housing 5, which is also rotatably mounted, but in the opposite direction from the rotation of the injection screw 4. At the same time, on the outside of the housing 5 there are turns of the screw 6 located in the peripheral coaxial channel 7 limited by the extruder body 2.

Inside the vacuum sublimation chamber 1 (Fig. 1), a nozzle in the form of a Laval nozzle 8 is installed around the outlet openings of the channels of the extruder 2, the diameter of the narrow part of which is 15-20% larger than the diameter of the peripheral coaxial channel 7 of the extruder 2. Moreover, the Laval nozzle 8 is narrow in its narrow part allows you to create a steam hydrodynamic shutter separating the product supply zone with a pressure above the triple point from the zone of self-freezing and freeze-drying with a pressure below the triple point. The nozzle in the form of a Laval nozzle 8 after its narrow part is provided with sources 9 of microwave energy (for example, magnetrons). In this case, the microwave energy sources 10 located on the lower generatrix of the Laval nozzle 8 are installed with the possibility of changing the angle of inclination. In the lower part of the vacuum sublimation chamber outside the range of microwave energy sources 10 there is a dividing-packing device 11. The installation has a lock gate 12 for unloading the finished product from the dryer and a remote desublimator (not shown).

A method of obtaining freeze-dried foods is as follows.

Previously (figure 2) is driven into rotation by the auger of the central channel and its housing, but they rotate in opposite directions.

The initial product with a high dry matter content (for example, 30-50%) is supplied to the peripheral coaxial channel 7 (Fig. 1), in which, under the action of the turns of the screw 6 of the housing 5, it moves to the entrance to the vacuum chamber 1 of the freeze dryer.

When a product with a high solids content (for example, 30-50%) enters the vacuum chamber 1 of the dryer, moisture enters from the dryer through the coaxial peripheral channel 7 and moisture vapor intensively evaporates from it, the vapor of which allows you to create a steam lock in the narrow part of the Laval nozzle 8 and form a zone (Fig .1) with a residual pressure near the triple point, but not lower than it (for example, 611-620 Pa), which ensures that the channels 4, 7 of the extruder 2 are blocked by a self-frozen product. Due to the high solids content, i.e. a small amount of moisture in this product, under the action of vacuum, its rapid dehydration, compaction and the formation of a tubular dried frame (Fig.2).

In addition, a product with a high content of fat or sugar can be introduced through the coaxial peripheral channel, since the moisture in these products is not connected and foams so intensely that it allows you to adjust the thickness and shape of the tow frame.

Upon reaching the tubular dried frame of the narrow part of the Laval nozzle 8 and entering the self-freezing zone with a residual pressure below the triple point (for example, 609-100 Pa), a product with a low dry matter content is fed through its central screw 3 through the injection screw 4 (for example , 3-10%). In the inner cavity of the tubular frame, a product with a low dry matter content boils and forms a foam structure, which self-freezes in the zone with a residual pressure below the triple point to obtain a highly developed evenly distributed porous structure.

The formed product bundle moves to the zone of action of the microwave energy field from sources 9, 10, where, simultaneously with evaporative freezing, the product is freeze-dried at a working residual pressure (for example, 50-100 Pa) with the final formation of a highly developed uniformly distributed porous structure due to intense sublimation of moisture .

Next, the dried product bundle is fed into a fusion packaging device 11 and discharged from the installation by means of a lock gate 12.

The proposed method has the following advantages:

- extrusion of the product by extrusion both on the central channel of the extruder and on the peripheral channel coaxial to it and introducing at the same time on the coaxial channel of the product with a high content of dry matter, fat or sugar, followed by the formation of a dried product frame due to intensive evaporation of moisture under it the action of rarefaction at a residual pressure near the triple point, but not lower than it, and through the Central channel the implementation in this frame of the product, having a low dry matter content, allows they are able to obtain a product with desired properties and high quality at low energy consumption;

- feeding into the inner cavity of the tubular dried frame of the product with a low dry matter content (for example, 3-10%) when it reaches a narrow part of the Laval nozzle and entering the self-freezing zone with a residual pressure below the triple point allows the formation of foam self-frozen mass inside the frame, which ensures reliable, uninterrupted production of a product with a highly developed evenly distributed porous structure, which has fast solubility and a corresponding original taste.

Claims (2)

1. A method of obtaining sublimated food products, including molding the starting product by extrusion by extruding it through the central channel of the extruder directly into a sublimation chamber into a zone with a pressure above a triple point created by a steam shutter from vapors formed as a result of intense evaporation of moisture in the feed zone product with obtaining highly developed uniformly distributed porous structure, evaporative freezing of the product in the zone with a pressure below the triple point and its sublim drying in a microwave energy field, followed by removal through a lock gate, characterized in that the product is additionally extruded through a coaxial peripheral with respect to the central channel, while a product with a solids content of 30-50% is introduced through the coaxial peripheral channel with the subsequent formation of dried the product frame due to the intense evaporation of moisture from it under the action of rarefaction at a residual pressure of 611-620 Pa, and through the central channel is carried out in this frame feeding the product having a solids content of 3-10%. 2. The method according to claim 1, characterized in that a high fat or sugar product is introduced via a coaxial peripheral channel.

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