RU2134524C1 - Method of preparing dry protein concentrates - Google Patents

Abstract

FIELD: food industry, particularly, production of dry protein concentrates for enteral alimentation. SUBSTANCE: method involves dispersion of initial emulsion with concentration of dry substances of 38-41%, foaming, and application of foamed product on dried surface in vacuum at pressure not more 8 kPa. Application of product on surface is carried out by spraying with specific volume load of 0.0006-0.0008 cu.m/sq.m. Drying is conducted at infrared heating with energy illumination. EFFECT: higher efficiency.

Description

 The invention relates to methods for producing dry protein combined milk-based concentrates and can be used in the food and medical industry in the production of dry balanced products for enteral nutrition such as “Ovolakt”.

 There is a method of obtaining dry fish hydrolysates [2], including preliminary dispersion of the product, foaming in vacuum, applying the foamed product by spraying onto a drying surface and drying in vacuum with infrared energy supply.

In the traditional technology of the Ovolact product (TU 10-02-02-54-87 (hereinafter - TU)) [1] the emulsion obtained is dried with hot air at a temperature of 150 - 190 ^o C in convective direct-flow spray dryers.

This drying method does not allow to obtain high-quality dry products due to uneven drying of product particles of various sizes, which has a special effect due to the inability to obtain a uniform composition of the sprayed particles by existing spray methods, which leads to local drying of large particles and burning of small particles. Lack of drying of large particles leads to clumping (agglomeration) of the latter, which increases the dispersion of particle sizes. In addition, convective spray drying leads to large losses due to the settling of a wet adhesion product having high adhesion on the walls of the dryer and has a low specific productivity (less than 7 kg / (m ³ • h)) due to surface energy supply and low internal moisture transfer efficiency, which leads to large dimensions of the dryer.

 The aim of the invention is to increase the productivity of the method and improve the quality of products for enteral nutrition.

The quality can be improved by achieving uniform volume moisture and, as a result, improving the organoleptic characteristics of the product, as well as by increasing the solubility of the dry concentrate due to the production of a highly developed product surface with a microporous (finely dispersed) foam structure during drying. The increase in productivity is provided by reducing the duration of the drying process by ensuring the stability of the foam structure, the effect of volumetric energy supply and intensive volumetric self-evaporation with a foam layer under vacuum, as well as an increase in the unit volumetric load of the apparatus in the initial product (kg / (m ³ • h)). Loss reduction occurs due to the directional application of the sprayed product on the working surface of the dryer and the absence of loss of fine powder with exhaust air.

The goal is achieved in that in the method of drying products for enteral nutrition (PEP), which includes foaming a liquid emulsion, applying a foamed product to a drying surface and drying, according to the invention, a pre-dispersed liquid emulsion with a solids concentration of C = 38 - 41% is foamed in vacuum with a residual pressure P of not more than 8 kPa. The application of the foamed product is carried out by spraying in vacuum at P <8 kPa with a specific volumetric load l = 0,0006 - 0,0008 m ³ / m ² . Drying is carried out with an infrared energy supply with a heat flux density of 2 - 4 kW / m ² .

 The method is as follows.

The initial liquid emulsion with a solids concentration of 38 - 41% is subjected to dispersion, fed to a vacuum chamber where foaming takes place, and then uniformly applied by spraying at P <8 kPa with a specific volumetric load l = 0,0006 - 0,0008 m ³ / m ² to the working surface of the dryer and then dried with infrared energy supply with a heat flux density E = 2 - 4 kW / m ² .

 This allows you to get a high-quality product of white color with a finely dispersed structure, easily detachable from the work surface.

 Foaming of the mixture in vacuum occurs due to intense internal self-evaporation of the product, superheated relative to the evaporation temperature at P <3 kPa, as well as degassing of the emulsion (expansion of air and its release from the product with a sharp decrease in pressure).

 The preliminary dispersion of the product is carried out by known methods: using mixing devices, circulating the solution along the circuit, and sparging the solution with air.

The specific removal rate of a dry product (specific productivity P, kg / (m ² • h) or kg / (m ³ • h)) depends on the concentration of solids in the initial emulsion (%), surface heat flux density (kW / m ² ) , the residual pressure in the vacuum chamber (kPa) and the specific volumetric load on the initial product (m ³ / m ² ).

 An increase in the concentration of the initial emulsion leads to an increase in the stability of the foam structure and removal of the dry product, here the maximum concentration is 41%, which is due to the technical conditions for feeding the product into the vacuum chamber and uniform spraying of the emulsion. A decrease in C of less than 38% leads to the decay of the foam structure, the glass transition of the final product, which, due to its high adhesion, is difficult to separate from the working surface, as well as a decrease in the drying efficiency.

 At pressures in the chamber of more than 8 kPa, the foam layer either does not form at all or is destroyed very quickly, the drying process is ineffective, and the dried product is difficult to remove from the surface. At a pressure in the chamber of less than 8 kPa, a significant increase in the efficiency of the process takes place. Therefore, it is advisable to carry out the drying process at a residual pressure of not more than 8 kPa.

The value of the heat flux density, it is advisable to maintain in the range of 2 to 4 kW / m ² mainly 4 kW / m ² Its increase is impractical due to burning of the drying product as well as decay of the foam structure, a decrease leads to a decrease in the specific removal of the dry product.

An increase in the specific volumetric load (foam layer thickness), on the one hand, leads to an increase in the drying time, and, on the other hand, to a more complete internal absorption and scattering of infrared energy, as well as to an increase in the removal of dry product per unit area. The load l = 0.0006 - 0.0008 m ³ / m ² is advisable due to the technical limitations of applying the product to the dryer surface.

The application of the proposed method allows to achieve a specific productivity of 12 kg / (m ² • h) or 60 kg / (m ³ • h) compared with 7 kg / (m ³ • h) for traditional technology.

The application of the proposed method improves the quality of the product:
- increase the solubility of the dry concentrate (the product obtained by the proposed method is almost instantly dissolved in cold water without stirring)
- get a product with a highly developed surface and fine-porous foam structure.

 Thus, the proposed method satisfy the criteria of the invention of "industrial applicability".

The proposed method differs from the traditional one in that the pre-dispersed emulsion with a solids concentration of 38 - 41% foams in vacuum at a residual pressure of less than 8 kPa, the foamed product is applied by spraying with a specific volumetric load of 0.006 - 0.008 m ³ / m ² and drying is carried out with infrared energy supply with a density of 2 - 4 kW / m ² .

 Thus, the proposed method satisfy the criteria of the invention of "novelty" and "inventive step".

 The proposed method is illustrated by examples.

Example 1. The initial liquid emulsion prepared according to traditional technology is brought to a solids concentration of 41%, pre-dispersed and introduced into a vacuum dryer with a residual pressure of 8 kPa, where the initial mixture is foamed. The foam is uniformly sprayed with a centrifugal atomizer with a specific volumetric load of 0.0009 m ³ / m ² and dried with an infrared energy supply with a surface density of 2.2 kW / m ² . As a result, the product is easily separated from the drying surface, the specific removal of the dry product is 3.77 kg / (m ² • h) (18.85 kg / (m ³ • h))).

Example 2. The operations were carried out according to example 1 with the following differences: E = 1.2 kW / m ² ; l = 0.0003 m ³ / m ² .

In this case, P = 2.25 kg / (m ² • h) (11.25 kg / (m ³ • h)).

Example 3. The operations were carried out according to example 1 with the following differences: E = 2.7 kW / m ² ; l = 0.0004 m ³ / m ² .

In this case, P = 4.43 kg / (m ² • h) (22.15 kg / (m ³ • h)).

Example 4. The operations were carried out as in example 1 with the following differences: E = 4 kW / m ² ; l = 0.0006 m ³ / m ² P = 2.5 kPa.

In this case, P = 10.03 kg / (m ² • h) (50.15 kg / (m ³ • h)).

Example 5. The operations were carried out according to example 1 with the following differences: E = 4 kW / m ² ; l = 0.0007 m ³ / m ² P = 2.5 kPa.

In this case, P = 12.00 kg / (m ² • h) (60 kg / (m ³ • h)).

Example 6. The operations were carried out according to example 1 with the following differences: E = 1.2 kW / m ² ; l = 0.0004 m ³ / m ² C = 38%.

In this case, P = 5.10 kg / (m ² • h) (25.5 kg / (m ³ • h)).

 Example 7. The operations were carried out as in example 1 with the following differences: C = 38%.

In this case, P = 4.94 kg / (m ² • h) (24.7 kg / (m ³ • h)).

Example 8. The operations were carried out according to example 1 with the following differences: E = 2.7 kW / m ² ; C = 38%.

Moreover, P = 3.86 kg / (m ² • h) (19.3 kg / (m ³ • h)).

Example 9. The operations were carried out according to example 1 with the following differences: E = 4.0 kW / m ² ; l = 0.0004 m ³ / m ² ; C = 38%.

In this case, P = 6.48 kg / (m ² • h) (32.4 kg / (m ³ • h)).

Example 10. The operations were carried out according to example 1 with the following differences: E = 1.2 kW / m ² ; l = 0.0004 m ³ / m ² ; C = 35%.

Moreover, P = 1.35 kg / (m ² • h) (6.75 kg / (m ³ • h)).

Example 11. The operations were carried out according to example 1 with the following differences: l = 0,0003 m ³ / m ² ; C = 35%.

Moreover, P = 1.73 kg / (m ² • h) (8.65 kg / (m ³ • h)).

Example 12. The operations were carried out as in example 1 with the following differences: E = 2.7 kW / m ² ; l = 0.0006 m ³ / m ² ; C = 35%.

At the same time, P = 4.58 kg / (m ² • h) (22.9 kg / (m ³ • h)).

Example 13. The operations were carried out as in example 1 with the following differences: E = 4.0 kW / m ² ; l = 0.0006 m ³ / m ² ; C = 35%.

Moreover, P = 6.09 kg / (m ² • h) (30.45 kg / (m ³ • h)).

Example 14. The operations were carried out as in example 1 with the following differences: E = 1.2 kW / m ² ; l = 0.0003 m ³ / m ² ; C = 32%.

Moreover, P = 1.98 kg / (m ² • h) (9.9 kg / (m ³ • h)).

Example 15. The operations were carried out according to example 1 with the following differences: l = 0,0006 m ³ / m ² ; C = 32%.

In this case, P = 1.46 kg / (m ² • h) (7.3 kg / (m ³ • h)).

Example 16. The operations were carried out as in example 1 with the following differences: E = 2.7 kW / m ² ; l = 0.0003 m ³ / m ² ; C = 32%.

In this case, P = 2.44 kg / (m ² • h) (12.2 kg / (m ³ • h)).

Example 17. The operations were carried out as in example 1 with the following differences: E = 4.0 kW / m ² ; C = 32%.

In this case, P = 4.67 kg / (m ² • h) (23.35 kg / (m ³ • h)).

Example 18. The operations were carried out as in example 1 with the following differences: E = 4.0 kW / m ² ; C = 32%; P = 12 kPa.

In this case, P = 0.91 kg / (m ² • h) (4.55 kg / (m ³ • h)).

 Thus, the proposed method allows to increase productivity and improve the quality of dry products for non-nutritional nutrition.

Sources of information taken into account:
1. TU 10-02-02-54-87.

 2. USSR author's certificate N 1634231, A 23 J 1/04, 1991.

Claims (1)

A method of obtaining dry protein concentrates, including dispersing the original liquid emulsion, foaming, applying the foamed product to the drying surface and drying, characterized in that the emulsion is brought to a solids concentration of 38-41%, foaming and applying the foamed product is carried out in vacuum at a pressure of not more than kPa, while applying the product to the surface is carried out by spraying with a specific volumetric load of 0.0006-0.0008 m ³ / m ² , drying is carried out with an infrared energy supply with an energy supply with illumination of 2-4 kW / m ² .