JP4571896B2 - Method for producing dried food - Google Patents

Description

  The present invention relates to a method for producing a dried food product in which fluid food materials such as seasonings, fruit juices, sugar solutions, and fermented foods are dried in a reduced pressure environment.

  Conventionally, in the field of the food industry, dry powder treatment has been performed in order to improve the storage stability and ease of use of foods and extracts. As such a drying process, for example, a hot air drying method, a vacuum drying method, a method of concentrating using a reverse osmosis membrane or an ultrafiltration membrane, and the like are known. In particular, the product temperature during drying can be kept low, there is little deterioration in the taste, flavor and color of the raw food, and it is difficult to dry under normal pressure. The vacuum drying method is widely used because of the merit that the raw material can be dried.

  For example, in the following Patent Document 1, sugars, salt, alcohol, and taste ingredients are added to candy sweet sake to adjust the mixture to a mixture having a water content of 30 to 70 W / W% and a viscosity of 500 to 10,000 cps. It is disclosed that by drying under reduced pressure, it is possible to produce a dry amazake that is excellent in flavor and solubility and that retains the shape of rice bran.

Further, in Patent Document 2 below, a mass frozen product obtained by freezing a liquid raw material in a vacuum under vacuum is converted into a fine particle frozen product having a uniform particle size using a crusher or a granulator, and then the fine material is obtained. It is disclosed that the granular frozen material is dried under reduced pressure.
Japanese Patent No. 2632681 JP 2003-207268 A

  However, when a fluid food material is supplied in a reduced pressure environment, the food material boils instantaneously, and the food material scatters in the apparatus, or tends to swell and expand. For this reason, it is difficult to dry in such a shape that the surface area is large and the drying efficiency is high, and there is a problem that sufficient drying efficiency and recovery efficiency cannot be obtained.

  On the other hand, as in the above-mentioned Patent Document 2, if the object to be dried is once frozen and then dried under reduced pressure to sublimate moisture, that is, freeze-drying treatment, the food material is scattered in the apparatus. In general, however, energy consumption and device costs are high, and there are cost problems. Moreover, since the food used as a raw material is once frozen, there is a problem that the taste and flavor are deteriorated, and the nutritional value tends to be lost due to protein degeneration.

  Accordingly, an object of the present invention is to provide a method for producing a dry food that can be produced at low cost and with high productivity without impairing the original taste, flavor, and active ingredient of the food material.

In achieving the above object, the method for producing a dried food according to the present invention is a method for drying a food material in which a fluid food material is supplied to a reduced pressure drying chamber of 50 mmHg or less and dried. The viscosity of the flowable food material is supplied to the reduced pressure drying chamber at a temperature not higher than the boiling point of the flowable food material at the pressure of the reduced pressure drying chamber without freezing . The drying is performed by gradually raising the temperature so as not to cause scattering and significant swelling, and finally raising the temperature to the boiling point or higher .

According to the present invention, since it is supplied into the vacuum drying chamber at a temperature not higher than the boiling point of the food material, the food material does not suddenly boil immediately after the supply and does not swell or scatter around the surface area. The food material can be supplied to the vacuum drying chamber with a large and high drying efficiency, and the drying efficiency and recovery efficiency of the food material can be improved. Further, since the food raw material is not frozen, energy consumption and apparatus cost can be reduced, and there is no deterioration in taste and flavor due to freezing denaturation or the like, and a dry food with good flavor and high nutritional value can be obtained.
In addition, since the fluid food material is supplied into the vacuum drying chamber at a temperature not higher than the boiling point at the pressure of the vacuum drying chamber, the temperature is finally increased to the boiling point or higher to perform drying. Water can be efficiently removed from the raw material, and the time required for the drying process can be shortened.

In the present invention, a conveying means is provided in the vacuum drying chamber, a recovery means for collecting the dried food material is provided at a destination of the conveying means, and the fluid food material is placed on the conveying means. It is preferable to supply and collect the dried material of the food material by the collecting means . According to which this, the food material is supplied onto the conveying means of vacuum drying chamber, it is possible to take out continuously drying, it can produce a dry food efficiently. Moreover, it is preferable that the said conveyance means consists of a conveyance belt. Moreover, it is preferable that the said collection | recovery means consists of a means to grind | pulverize and take out the dried material of the said foodstuff raw material.

  Moreover, it is preferable to perform supply of the fluid food material by discharging from a circular nozzle having a diameter of 5 mm or less or a slit-shaped nozzle having a width of 3 mm or less. According to this, since it can be supplied in a shape with a large surface area, it is possible to increase the drying efficiency and dry the food raw material in a short time without drying unevenness.

  In addition, the above-mentioned fluid food materials include seasoning materials, fruit juice materials, extract materials made from agricultural products, extract materials made from marine products, extract materials made from livestock products, protein materials, proteolysate materials, fermentation It is preferable to use one or more selected from food materials.

  According to the present invention, the food material is supplied to the vacuum drying chamber at a temperature not higher than the boiling point of the food material, so that the food material does not suddenly boil immediately after the supply and swell to the surroundings. The raw material for food can be supplied to the vacuum drying chamber with a large surface area while maintaining the discharge shape at the time of supply, and as a result, the recovery efficiency and drying efficiency of the dried food can be improved. Moreover, since the food raw material is dried without freezing, there is no possibility of damaging the original taste, flavor, active ingredient, etc. of the raw material food.

  The method for producing a dried food according to the present invention is characterized in that a fluid food material is supplied to a vacuum drying chamber and dried at a temperature not higher than the boiling point of the pressure in the vacuum drying chamber without freezing.

  The type of fluid food material that can be used in the method for producing a dry food according to the present invention is not particularly limited. For example, seasoning raw materials, fruit juice raw materials, extract raw materials from agricultural products, and marine products as raw materials are used. Extract raw materials, extract raw materials made from livestock products, protein raw materials, proteolysate raw materials, fermented food raw materials, and mixtures thereof, etc., for the reason that flavor and appearance are likely to deteriorate due to heat drying, Fruit juice raw materials, vegetable juice raw materials, extract raw materials made from agricultural products, extract raw materials made from marine products, and extract raw materials made from livestock products are preferred.

  Examples of fluid food materials include dextrin, starch, dietary fiber, other saccharides and their degradation products, salts, milk proteins, vegetable proteins, other proteins and their degradation products, such as agar and gelatin. Thickeners such as xanthan gum, gum arabic, gellan gum, carrageenan, locust bean gum, guar gum, pectin, glucomannan, sodium alginate, potassium alginate, and other thickening polysaccharides can also be added. And it adjusts to 50-100,000 cps by adding the above excipient | filler, a thickener, or water suitably to a fluid foodstuff raw material, Preferably it is 1,000-10,000 cps. When the flowable food material has a viscosity of less than 50 cps, when the flowable material is supplied to the vacuum drying chamber, the discharge liquid tends not to maintain the discharge shape and tends to diffuse into the vacuum drying chamber. If it exceeds 100,000 cps, it becomes difficult to discharge from the nozzle.

  Moreover, it is preferable to adjust the said fluid food raw material to the temperature below the boiling point in the pressure of a reduced pressure drying chamber in the range which does not freeze. If the temperature of the flowable food material is adjusted as described above, there is no risk of sudden boiling when it is supplied to the vacuum drying chamber, and it will not scatter or swell. Can be supplied. On the other hand, once a fluid food material is frozen, there is a risk that the taste and flavor of the food as a raw material may deteriorate due to freezing, and the protein may be denatured. Furthermore, energy consumption in the subsequent drying process The amount becomes high and the running cost is increased.

  As a vacuum drying apparatus that can be used in the method for producing a dried food according to the present invention, a conventionally known vacuum drying apparatus used for vacuum drying of food can be used, and a conveying means is provided inside the vacuum drying chamber. A continuous reduced pressure drying apparatus capable of continuous processing having a recovery means for recovering the dried food material at the destination of the transport means is preferable because of its low running cost and good workability.

  As a specific example of such a continuous vacuum drying apparatus, for example, a belt type in which the conveying means as shown in FIG. 1 is a conveying belt and the collecting means is a means for pulverizing and taking out the dried food material. Examples of the vacuum drying apparatus include a drum type vacuum drying apparatus and the like, in which the transporting means is a drum and the recovery means is a means for peeling and taking out the dried food material from the drum. A belt type vacuum drying apparatus is particularly preferable.

  Moreover, the pressure in the vacuum drying chamber at the time of vacuum drying of the fluid food material is set to 50 mmHg or less, preferably 30 mmHg or less, and more preferably 10 mmHg or less.

  Depending on the solid content concentration of the fluid food material used, when the pressure in the vacuum drying chamber is 50 mmHg or less, the boiling point is usually 60 ° C. or less, and when it is 30 mmHg or less, the boiling point is 40 ° C. or less and 10 mmHg or less. In this case, the boiling point is about 20 ° C. or less, and when it is 5 mmHg or less, the boiling point is about 10 ° C. or less. In the present invention, the fluid food material is supplied to a region adjusted to a temperature not higher than the boiling point in the vacuum drying chamber. In this case, the flowable food material itself is preferably adjusted to a temperature not higher than the boiling point and not frozen.

  The temperature in the vacuum drying chamber can be adjusted by adjusting the atmospheric temperature in the vacuum drying chamber. However, when a conveyor such as a belt or a drum is provided in the vacuum dryer, the surface temperature of the conveyor is What is necessary is just to adjust so that it may become the temperature below a boiling point.

  Thus, by supplying the fluid food material to the region adjusted to a temperature below the boiling point in the vacuum drying chamber, it is possible to prevent the fluid food material from boiling suddenly, and as a result, the fluid food material is scattered around. For example, a plurality of parallel lines arranged in a narrow pitch can be supplied so as to have a large surface area and a high drying efficiency, and drying efficiency and recovery of fluid food ingredients Efficiency can be improved.

Moreover, elevated in the present invention, a vacuum drying chamber the fluid food material, until decompression drying chamber after fed at a temperature below the boiling point at a pressure, gradually increase the temperature, eventually the higher boiling point It intends rows dried by. The fluid food material is supplied at a temperature equal to or lower than the boiling point of the pressure in the vacuum drying chamber, so that the drying progresses while suppressing scattering and swelling to the surroundings. Drying can be completed in a shape that is easy to post-process without causing scattering or significant swelling. And after supplying a fluid food raw material in a reduced pressure drying chamber, the time which a drying process requires can be shortened by raising temperature as mentioned above, and the productivity of dried food can be improved. In addition, since there exists a possibility of damaging the taste, flavor, active ingredient, etc. of the foodstuff used as a raw material if it heats to 90 degreeC or more, it is preferable that an upper limit shall be 80 degreeC.

  Next, the method for producing a dried food according to the present invention will be described taking as an example the case where a belt-type vacuum drying apparatus as shown in FIG. 1 is used as the vacuum drying apparatus.

  In the belt-type vacuum drying apparatus 1, a storage tank 3 for storing a fluid food material and a vacuum drying chamber 2 are connected via a pipe 4. A dispersion nozzle 5 is disposed at the tip of the pipe 4. The dispersion nozzle 5 is located at the start end of the belt 6 in the vacuum drying chamber 2 and extends in the width direction, and has a plurality of nozzles arranged at predetermined intervals. And it has composition which can supply fluid food ingredients from a plurality of nozzles in a plurality of parallel lines. Further, a cutting device 13 having a cutting blade 12 is arranged on the ceiling of the vacuum drying chamber 2 located in front of the terminal end of the belt 6, and cuts the dried material conveyed from the belt 6, The pulverizer 10 can be supplied to the pulverizer 10 through a hopper 9 disposed at the bottom.

  Examples of each nozzle provided in the dispersion nozzle 5 include a circular nozzle, a slit-shaped nozzle, a polygonal nozzle, a curved slit nozzle, etc., which are excellent in maintainability and provide a stable discharge shape. A nozzle is preferred.

  As the circular nozzle, those having a diameter of 5 mm or less are preferable, and 0.5 to 2 mm is more preferable. The slit width of the slit nozzle is preferably 3 mm or less, and more preferably 0.5 to 2 mm. If the nozzle is a circular nozzle with a diameter of 5 mm or less, the fluid food material can be discharged in a thin line, and if the slit width is 3 mm or less, the fluid food material can be discharged in a thin sheet. The surface area per volume can be increased to increase the drying efficiency.

  A plurality of heat exchange plates 7 connected to the temperature controller 8 are arranged on the belt 6, and the region 6 a of the belt 6 immediately below the nozzle 5 is made of food at a pressure in the vacuum drying chamber 2 by the heat exchange plate 7 a. It is adjusted to a temperature below the boiling point of the raw material.

  The temperature of the belt 6 on the intermediate region 6b is preferably adjusted by the heat exchange plate 7b so as to be higher than that of the region 6a. The heat exchange plate 7b is divided into a plurality of temperature regions or a plurality of sheets. The fluid food material 11 on the belt 6 is preferably configured to gradually increase the temperature, and most preferably configured to be finally heated to the boiling point or higher.

  The belt 6 on the rear region 6c is preferably temperature-adjusted by a heat exchange plate 7c so that the food material 11 can be cooled.

  Next, a method for producing a dried food using this belt type vacuum drying apparatus will be described.

  The fluid food material adjusted to have the viscosity as described above is stored in the storage tank 3, then introduced into the vacuum drying chamber 2 through the pipe 4, and a plurality of parallel feeds from the dispersion nozzle 5. It is supplied to the region 6a of the belt 6 in a linear shape.

  As described above, the area 6a immediately below the dispersion nozzle 5 is adjusted to a temperature below the boiling point of the food material 11 in the vacuum drying chamber 2 by the heat exchange plate 7a. The food raw material 11 does not suddenly boil, scatters to the surroundings, or does not swell, and drying can proceed while maintaining a plurality of parallel lines.

  The method for discharging and supplying the fluid food material to the belt 6 is not particularly limited. For example, as shown in FIG. 2, it is preferable to discharge and supply the fluid so that the pitch width p is 1 to 100 mm, and 1 to 60 mm. It is more preferable to discharge and supply.

  When the pitch width p is less than 1 mm, the materials discharged in the form of belts stick to each other when expanded, and the shape may be lost, making it difficult to perform subsequent cutting and grinding treatment. This is not preferable because the discharge supply amount of the fluid food material is reduced, and as a result, the drying efficiency is lowered.

  Moreover, it does not specifically limit as a discharge shape of the fluid foodstuff raw material in this invention, Arbitrary shapes, such as a curve and a broken line other than the straight line like FIG. 2, can be selected. For example, by making the nozzle movable, it becomes possible to discharge in a curved line shape and a polygonal line shape. The shape can be maintained.

  And the fluid foodstuff raw material supplied to the area | region 6a of the belt 6 is conveyed by the area | region 6b temperature-controlled by the heat exchange plate 7b.

  It is preferable that the temperature of the belt 6 on the region 6b is adjusted by the heat exchange plate 7b so as to be higher than that of the region 6a. The heat exchange plate 7b is gradually divided into a plurality of temperature regions or a plurality of sheets, and gradually. Preferably, the food material 11 on the belt 6 can be gradually heated, and the fluid food material on the belt 6 can be finally heated to the boiling point or higher. Most preferred.

  Thus, by adjusting the temperature of the belt 6 on the region 6b, the fluid food material can be efficiently dried in a short time.

  The food material 11 that has been dried through the regions 6a and 6b is conveyed to the region 6c whose temperature is adjusted by the heat exchange plate 7c.

  When a fluid food raw material is used, one having a high fat content may be softened by the drying treatment in the regions 6a and 6b, and the subsequent cutting process may be difficult. Therefore, when such a fluid food material is used, the conveyed food material 11 is cooled in the region 6c.

  Then, the food material 11 conveyed to the region 6c is cut at a predetermined interval by the cutting blade 12, collected by the hopper 9, and then supplied to the pulverizer 10, where the pulverization process is performed and adjusted to a desired size. Dried food.

  Hereinafter, the effects of the present invention will be described using Examples and Comparative Examples. The belt-type vacuum drying apparatus shown in FIG. 1 was used as the vacuum drying apparatus.

Example 1
In 200 g of concentrated apple juice, 200 g of dextrin was dissolved and cooled to 5 ° C., and a stock solution (fluid food material) with a viscosity of 2,300 cps was reduced to 7 mmHg by a circular nozzle with a diameter of 2 mm. The toner was discharged and supplied onto the belt 6 whose temperature was adjusted to 5 ° C. As a result, this undiluted solution could be supplied onto the belt 6 with a clean line without scattering to the surroundings or swelling. Thereafter, the belt 6 was gradually heated with the plate 7b, and further heated to 70 ° C. with the plate 7c to dry the concentrated apple juice. The dried concentrated apple fruit juice was recovered with a hopper 9 and pulverized with a pulverizer 10 to obtain 270 g of concentrated apple fruit juice powder with a moisture content of 2% (recovery ratio 94.5%).

(Comparative Example 1)
In 200 g of concentrated apple juice, 200 g of dextrin was dissolved and cooled to 5 ° C., and a stock solution (fluid food material) with a viscosity of 2,300 cps was reduced to 7 mmHg by a circular nozzle having a diameter of 2 mm. The toner was discharged and supplied onto the belt 6 whose temperature was adjusted to 60 ° C. As a result, this undiluted solution is greatly scattered to the surroundings, and the linear undiluted solution discharged from the nozzles is connected to the belt 6 due to the expansion of the lines, and is supplied onto the belt 6 while maintaining the discharged shape. I couldn't.
Then, when the drying process was performed like Example 1, the moisture content of concentrated apple juice powder was 5%, and the recovery rate was 10% (28.6g).

  The present invention is suitable for drying seasoning materials, fruit juice materials, and the like.

1 is a schematic view of a belt-type vacuum drying apparatus that can be used in the method for producing a dried food according to the present invention. It is an example of the discharge supply to the belt 6 of a foodstuff raw material.

Explanation of symbols

1: belt type vacuum drying device 2: vacuum drying chamber 3: storage tank 4: piping 5: dispersion nozzle 6: belt 7, 7a, 7b, 7c: heat exchange plate 8: temperature controller 9: hopper 10: pulverizer 11 : Food raw material 12: Cutting blade 13: Cutting device

Claims (6)

In the method for drying a food material, the fluid food material is supplied to a reduced pressure drying chamber of 50 mmHg or less and dried, and the fluid food material is prepared so as to have a viscosity of 50 to 100,000 cps without being frozen. Under the temperature below the boiling point of the fluid food raw material at the pressure of the vacuum drying chamber, supply the vacuum food drying chamber, gradually increase the temperature so that the fluid food raw material does not scatter or significantly expand, A method for producing a dried food product, characterized in that drying is performed by raising the temperature to the boiling point or higher .   A conveying means is provided in the vacuum drying chamber, a collecting means for collecting the dried food material is provided at a destination of the conveying means, the fluid food material is supplied onto the conveying means, and the collecting is performed. The method for producing a dried food product according to claim 1, wherein the dried food material is collected by means. The process according to claim 2 food dry matter according to the conveying means comprises a conveyor belt. The method for producing a dried food product according to claim 2 or 3, wherein the recovery means comprises means for pulverizing and removing the dried food material . The method for producing a dried food product according to any one of claims 1 to 4 , wherein the supply of the fluid food material is performed by discharging the fluid food material from a circular nozzle having a diameter of 5 mm or less or a slit nozzle having a width of 3 mm or less. As the fluid food materials, seasoning materials, fruit juice materials, vegetable juice materials, sugar liquid materials, extract materials made from agricultural products, extract materials made from marine products, extract materials made from livestock products, protein materials The method for producing a dried food product according to any one of claims 1 to 5 , wherein at least one selected from a raw material for proteolysate and a raw material for fermented food is used.