KR820002244B1 - Method of manufacturing spray dried aggloemerated product - Google Patents

Abstract

The manufg method of spray-dried agglomerated product inducting inert gas into food extract and suspension before spray-drying was described. Extract and soln. or suspension passed through nozzle at the pressure changing from higher pressure than that of inert gas to lower pressure than that of inert gas, and then sprayed. The gas was partially removed from extract and soln. or suspension through nozzle using vibration instrument

Description

Method for producing granular food by spray drying

1 is a process diagram according to the method of the present invention particularly relevant to coffee processing.

2 and 3 show micrographs (magnification 61x) of the fruiting product of soluble coffee produced by the method of the present invention.

4 is a micrograph (61x magnification) of a soluble coffee product spray dried by conventional methods.

5 is a micrograph (61x magnification) of a soluble coffee product granulated in a conventional apparatus using the soluble coffee product shown in FIG.

6 is a micrograph (61x magnification) of a commercial dextrin expanded product.

7 is a micrograph (magnification 100 times) of the granular dextrin product prepared by the method of the present invention.

8 is an enlarged photograph (magnification 100 times) of a drum-dried dextrin product.

The present invention relates to a method for producing granular foods obtained by spray drying. Representative products that can be prepared by the process of the present invention are dry soluble coffee powder, swelled dextrin and the like.

Spray drying and granulation are known unit operations that have been employed in the food processing industry for a considerable time. In general, however, spray drying and granulation are separation processes performed step by step on coffee extracts, liquid milk and the like. This stepwise separation method is unreasonable in terms of saving of plant equipment, utilization of equipment and production time. Therefore, it is desirable if the spray drying and granulation methods combined in a single process can increase the production capacity of the food processing plant equipment and at the same time reduce the amount of equipment and the production period. The concept of spray drying and granulation methods combined in a single process has been described so far in several US patents: US Pat. No. 3,514,300 by Mishkin et al. And US Pat. No. 3,151,984 by Peebles et al. It is described in. In the method of the co-inventor of Michinkin et al., The recycled fine substance is used for preparation of granular soluble coffee powder. In the process of the Peebles co-inventor, the milk concentrate containing the added lactose crystals is introduced into a spray dryer to obtain granular material having a water content of 10 to 20% while appropriately controlling the drying conditions. Subsequently, in order to further reduce the water content, the second drying step is employed in the process of the Peebles co-inventor. However, both processes of Mishkin and Peebles require a two step separate drying process. In other words, in the method of Michinkin, a drying operation necessary for preparing coffee fine powder is required, while in the Peebles method, granules are not only used to introduce lactose crystals, which are essential ingredients, into the spray dryer, but also to obtain fine powdered milk. A second drying operation is required to reduce the water content of the phase material to the final water content of the powdered milk.

The concept of foaming coffee extracts and other extracts and food suspensions to control the color, density and particle size of the final product has also been presented. Therefore, US Patent No. 2,788,276 to Reich et al. Discloses a method of spray drying foamed materials such as coffee. However, the purpose of this patent is to produce a product having a discontinuous spherical structure that does not aggregate or become granular.

The present inventors use a two-part nozzle to mix an inert gas with an extract, solution or suspension of a food, and when the specific pressure of the extract, solution or suspension is changed, small droplets are then removed. It has been discovered that fine spray-dried products having the appearance of granular products can be produced by being fused at the same time according to the vibration mechanism (vibration pattern) in the spray vortex band of the spray dryer.

The inventors have found that granular products can be obtained by spray drying the dextrin solution and other extracts, solutions or suspensions of various foods, as well as coffee extracts simultaneously in a single process step. According to this method, it is possible to produce granular products having a certain range of color characteristics as well as an unusual physical appearance.

This method is advantageous in that it does not need to be equipped with a standard granulation device such as a granulation tower in a soluble coffee processing device. Moreover, this method can increase the yield of soluble coffee processing equipment by converting existing granulation towers into spray granulation towers.

It is an object of the present invention to introduce an inert gas, such as nitrogen or carbon dioxide, into a extract, solution or suspension of a food, usually a coffee extract or dextrin solution, using a two-fluid nozzle, followed by a non-uniform extract, solution or suspension. Providing a method for producing granular foods by spray drying, wherein the extract, solution or suspension is sprayed and partially degassed by using a conventional spray nozzle with vibration of a spray mechanism [pattern]. It is for.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings and examples.

In FIG. 1, the coffee extract extracted from a percolator and evaporated to a concentration of 25-35% is fed to the liquid inlet of a two-fluid nozzle by a high pressure air piston pump, where an inert gas such as nitrogen and The coffee extract is thoroughly mixed to form a foamy extract. Power from the air piston pump is used to move the foamed phase extract to a known high pressure cored nozzle inside the spray dryer. A check valve is installed between the air piston pump and the two-fluid nozzle and between the inert gas supply port and the two-fluid nozzle. Extraction pressure and gas pressure in the two-fluid nozzle are higher than the air pressure when the piston pump applies the maximum extraction pressure to the two-fluid nozzle, and similarly, the gas pressure is two-fluid when the pump pressure is low. Balance to equal or higher than the liquid extraction pressure applied to the nozzle. Such fluctuations in gas pressure and liquid pressure result in vibrations of the nozzle mechanism in the spray dryer, as well as fluctuations in the amount of gas mixed with the extract. With this vibration, even under pressure above the minimum spray pressure, partial granulation associated with the operating pressure spray nozzles at the minimum spray pressure is repeated, so that a slight nozzle pressure drop occurs, so that no spraying phenomenon occurs. The frequency of vibration of the nozzle spray mechanism can be controlled by the relative size of the spray nozzle inside the feed pump and the dryer. Collision and subsequent fusion phenomena of the spray particles can be sustained by increasing the vibration frequency of the spray apparatus. The pump pressure and thus the extraction pressure are substantially changed in accordance with the required minimum pressure variation of 1.70 to 2.05 kg / cm 2 · G (10 to 15 psig). Although the most effective granulation occurs when the gas and extraction pressures are about the same, in some cases granulation occurs when the gas pressure is lower than the extraction pressure, and the degree of granulation decreases as the gas pressure against the extraction pressure is lower. Since the critical variable is the ratio of the extraction pressure to the gas pressure expressed in terms of the liquid pressure and the gas pressure for the two-fluid nozzle, granulation occurs at any pressure of low and high spray nozzle pressures. Therefore, the operating range of the spray dryer nozzle is determined by the predetermined feed rate for the spray dryer. The granulation method can be applied to other foods such as dextrin in addition to coffee extracts. If necessary, the spray dried product of the present invention can be redried to obtain a product having a low water content.

Example 1

The coffee extract at a concentration of 35% and a temperature of 37 ° C. was passed through a Graco® air piston pump through Spraying Systems ™ two-fluid pneumatic mixing nozzle (type 40100/125328). . The extraction pressure and nitrogen gas pressure in this mixing nozzle were 7.03 kg / m 2 and 6.9 kg / m 2, respectively. By using the Spraying Systems (Whirljet Type 1-1) nozzle in a spray dryer, the average pressure of the foamed phase extract on this nozzle was maintained at 6.7 kg / m 2.

The inlet and outlet temperatures of the spray dryer were 221 ° C and 131 ° C, respectively. The average particle size of the resulting product was 834 microns (compared to the control particle size of 283 microns), the density was 13.8 g / 100 mm 3, and the flavor change in the final product could not be clearly detected.

Example 2

Coffee extracts with a concentration of 40% and a temperature of 21 ° C. were passed through a Spraying Systems ™ two-fluid pneumatic mixing nozzle (type 100150/189251) by means of a Graco® air piston pump. . The extraction pressure and nitrogen gas pressure in the two-fluid type mixing nozzle were 12.65 to 21.1 kg / m 2 and 14.1 kg / m 2, respectively. An average nozzle pressure of 17.6 kg / m 2 was maintained on a spraying system (Spraying Systems ™) [Whirljet Type 2-2] nozzle of the spray dryer. The inlet temperature of the spray dryer was 182 degreeC, and the outlet temperature was 127 degreeC. The average particle size of the expanded product was 640 microns, the density was 19.1 g / 100 ㏄, and the water content of the final product was 23.2%.

Example 3

Dextrin [Morex 1918] at a concentration of 60% and a temperature of 88 ° C. was sprayed by a Graco air piston pump. [Spraying Systems] 2-fluid type mixing nozzle (type 100150/189351) Passed). The liquid pressure and nitrogen gas pressure in the two-fluid nozzle were 49.2 kg / m 2 and 21.1 kg / m 2, respectively. Manton Gaulin® to generate higher nozzle pressures of 77.3 kg / m2 in Spraying Systems® nozzles (Whirljet Type 1-1) in spray dryers. A positive displacement pump was used. The temperature of the spray dryer inlet was 293 ° C, and the temperature of the outlet was 132 ° C. Feed rates for solids per hour ranged from 136.1 kg to 158.8 kg. The density of the expanded product was 4.6 g / 100 kPa.

Although there is no particular theory in carrying out the spray granulation method of the present invention, all pressure nozzles employed in spray drying appear to have a minimum critical pressure required to cause a proper jet phenomenon. By operating at such a narrow range of critical pressures, large spray droplets can be formed, but various adjustment mechanisms occur because adjustment of operating conditions is difficult. By using a two-fluid nozzle pneumatic mixer as a means for blowing the feed to conventional spray nozzles above the critical pressure, (1) no extreme fluctuations occur in the spray apparatus, and (2) controlling the density of the final product. The ratio of extract to inert gas can be finely controlled.

According to the spray granulation method of the present invention, which applies a high ratio of inert gas to the extract, it is possible to obtain a granular product by spray drying, that is, soluble coffee and dextrin having a new physical shape, that is, a large spherical fusion.

Claims (1)

In preparing spray dried foods by introducing an inert gas into the extract, solution suspension of food and spray drying prior to spray drying, the extract, solution or suspension is subjected to a pressure varying from a pressure range higher than the pressure of the inert gas to a low pressure range. By spray drying after passing through a fluid nozzle and partially extracting the extract, solution or suspension through the nozzle with a vibrating mechanism of the spray drying chamber to recover the spray dried food having the appearance of granular food. Method for producing granular foods.

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