JPH0412105B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to an economical and efficient method for producing dipeptide sweetener granules with improved physical properties. α-L-Aspartyl-L-phenylalanine methyl ester (hereinafter referred to as "aspartame") has a high-quality sweetening chamber and approximately 200 times the sweetening power of sucrose, so it can be used in various foods. It is a promising low-calorie sweetener. "Aspartame" crystal powder (hereinafter referred to as bulk powder) is produced using L-aspartic acid and L-phenylalanine as starting materials, which is crystallized by an appropriate method, then solid-liquid separated, and then dried. and get it. Conventionally, when aspartame is provided as a sweetener, the bulk powder is used as it is or is granulated. However, it has been pointed out that products prepared by the bulk powder itself or by granulation using conventional methods often suffer from several problems due to the physical properties inherent to aspartame in actual use. For example, aspartame bulk powder is generally fine needle-shaped crystals, so it has a large specific volume and has powder characteristics that make it easy to scatter. Therefore, there is a risk that the particles may scatter during handling operations, worsening the working environment, and losses due to scattering are likely to occur. In addition, due to the electrostatic properties of aspartame, it may adhere to the equipment walls, resulting in adhesion loss, and may easily form bridging, which may prevent smooth mixing with other raw materials or cause clogging of the equipment. This tends to cause problems in mixing operations, weighing and filling operations, etc., and it is difficult to obtain uniform products. Even once it is mixed uniformly with excipients, aspartame tends to re-agglomerate among itself during distribution or storage, resulting in classification, resulting in a non-uniform state, and at the same time, there is a tendency for fluidity to be lost. Furthermore, while aspartame has the advantage of being difficult to deliquesce upon moisture absorption, it also has the disadvantage of poor dispersibility and solubility in water. When used in various foods, it is a major disadvantage in food processing that lumps occur when dissolved in water, making the dissolution operation difficult, taking time, and causing foaming. Conventionally, various methods have been attempted to improve the physical properties of aspartame. A typical example is a method in which aspartame is previously made into an aqueous solution alone or together with an excipient, or made into a slurry, and then dried. This method is effective in improving the dispersibility and solubility of aspartame and producing a uniform aspartame preparation.
On the other hand, since dipeptide sweeteners with poor solubility and dispersibility must be dissolved in water or made into a slurry, operational difficulties are unavoidable, and many problems arise in the process, such as aspartame foaming when dissolved. Furthermore, it is expected that during the drying process, the dipeptide sweetener will decompose due to heat and become a diketopiperazine derivative that is non-toxic and completely safe but has no sweet taste, resulting in a loss of sweetness. In addition,
It is necessary to evaporate a relatively large amount of water, which is disadvantageous in terms of energy, and also imposes a certain burden in terms of cost. For this reason, especially in the manufacturing process of processed foods (seasonings, sweeteners, beverages),
Adopting the above-mentioned treatment for improving the physical properties of aspartame as a so-called pretreatment cannot be said to be advantageous in terms of process control and energy costs. Furthermore, aspartame's function is to sweeten foods with high bulk density and low calorie, but such functions are impaired when large amounts of excipients are used together. In addition, the cost of packaging material increases by the amount of excipient, and depending on the type of excipient, it may affect the quality of sweetness or cause browning. The present inventors have conducted extensive studies in order to eliminate these problems arising from aspartame bulk powder and the disadvantages that arise when granulating it using conventional methods, and to obtain an aspartame product with improved physical properties using an industrially advantageous method. As a result of repeated steps, a specific amount of water is added to the aspartame crystals and the mixture is stirred or
Aspartame is crystallized in an aqueous solvent solution with a concentration of 35% or more, the mother liquor is separated, water is added again to adjust the moisture content, and the mixture is stirred and mixed, either as it is or after extrusion treatment and then dried. The present invention has been completed based on the finding that aspartame granules can be efficiently obtained which solves the above problems. The aspartame (crystal) used in the present invention preferably has the X-ray diffraction pattern shown in FIGS. It is difficult to granulate materials having diffraction patterns of the type and ' type shown in the figure. Aspartame is a polymorph with two or more crystal systems, but it can generally be classified into two types: anhydrous and hydrate. Which crystal form is produced depends on the formation conditions such as crystallization conditions and drying conditions. Polymorphic changes, ie, transitions, occur between crystals belonging to these different crystal systems under certain conditions. Normally, during crystal formation, an unstable crystal is first formed, which often transforms into a stable crystal. Aspartame is an intertransitional crystal, and the present inventors discovered that the apparent adhesive force becomes stronger in the process of transitioning from the type and '' type to '' type, and utilized this adhesive force as a binder. .
For example, when starting materials are the conventional crystal forms of the type and ' type as shown in the X-ray diffraction patterns of FIGS. 3 and 4, no apparent adhesive force is generated. It is difficult to end crystal comrades. The amount of water added to aspartame (crystals) is 35 to 45% as the water content of the stirred mixture, but if the water content is within this range, the transition of crystal form will proceed in a short time and the crystals will form together. Apply and granulate.
Since these granules form a fluorite-like tissue structure and have low water content, they have good drying efficiency and do not require a crushing step after drying. If the moisture content is less than 35%, the adhesive strength necessary for binding cannot be obtained, and if it exceeds 45%, so-called kneading tends to occur, scaling to the equipment occurs, and granulation becomes difficult. That is, moisture 35
The optimum ratio is ~45%, but the particle size can be made uniform by passing the stirred mixture through a sizing machine such as an oscillator, and a product with a desirable appearance can be obtained. Further, when the above-mentioned mixture is extruded using an extrusion granulator, high-density massive granules can be directly obtained by passing it through a screen having a diameter of 0.8 to 2.0 m/m. In this case, small pores with high moisture content are denser than large pores with low moisture content, but regardless of the moisture content,
If the screen has a diameter of 0.8 m/m or less, heat generation will be intense during extrusion and the density will be too high, so that solubility will not improve. On the other hand, if the screen has a diameter of 2.0 m/m or more, it will not be compressed sufficiently, so the density will not be high and the granule strength will be weak. When using crystal mud, the crystal mud is obtained by crystallizing aspartame in an aqueous solution of methyl alcohol or ethyl alcohol with a concentration of 35% or more, removing a part of the mother liquor by centrifugation or other methods, and then drying the crystal mud. Use it as is. If the concentration of methyl alcohol, ethyl alcohol, etc. is less than 35%, the crystal form of aspartame in the crystal slurry will become a shape, and adhesive strength during crystal system transition will not be obtained.
The mother liquor may be removed by centrifugation or the like as long as the solvent concentration in the adhering mother liquor is 35% or less when the water content is adjusted to 35 to 45% by rehydration. in particular,
When a portion of the mother liquor is removed by centrifugation or the like, the amount of adhering mother liquor must be 45 to 56% or less. If the crystalline mud is used as it is, the process can be simplified and the decomposition of aspartame can be minimized, so there are great industrial advantages. The mixture may contain ingredients other than aspartame, but if a large amount of starch-based and protein-based excipients is added, it may increase calories,
It cannot be said to be preferable because it may cause changes in taste and flavor. On the other hand, the addition of surfactants such as glutamic acid, aspartic acid and other amino acids, citric acid, tartaric acid and other organic acids and their salts, sucrose fatty acid ester, sorbitan fatty acid ester, etc. facilitates the mixing operation, and It is preferable because it contributes to stabilizing aspartame in the drying process, improving taste, and further improving powder properties such as antistatic properties and improving solubility. The optimum amount of amino acids and organic acids to be added is when the pH of the mixture is in the range of 3.0 to 3.5 in terms of powder properties, solubility, and usability in foods. When adding citric acid, the composition ratio should be 0.2 to 1.5 moles of citric acid to 1 mole of aspartame. It is desirable that the surfactant is water-soluble, and the amount added is 0.1 to 0.5 in the mixture.
% is optimal. If it is less than that, it will not be effective,
Adding more than that is meaningless. Excessive addition tends to eventually reduce the granule strength. Although the drying method is not particularly limited, low-temperature ventilation drying using dehumidified air, hot air drying at 90°C or lower, vacuum drying at 70°C or lower, etc. will reduce the decomposition of aspartame during drying, and the final product will be ′-type aspartame. Since granules can be obtained, granules with excellent solubility can be efficiently collected. On the other hand, in the case of drying at 90° C. or higher, the aspartame crystal form of the final product becomes shaped and 'shaped granules, so the stability is good but the solubility is poor. The present invention relates to a method for efficiently obtaining aspartame granules with improved physical properties by utilizing the intertransferability of aspartame crystals without relying on a third component such as a binder. According to the method of the present invention, aspartame, which is a starting material, can be granulated using crystal slurry as well as bulk powder, provided that the crystal form is type or type. Since it does not require the use of binders or excipients, it is naturally a high-concentration aspartame product, which eliminates the sensory effects of the third component, and dramatically improves solubility, dispersibility, and other physical properties of the product. Since it can be improved, it will greatly contribute to improving the handling and usability of aspartame. The present invention will be further explained below with reference to Examples. Example 1 Type of aspartame crystal powder *600g and 323ml of water
Add g and mix in a kneader for 15 minutes, and then
The product was extruded and granulated using a screen with a diameter of 2.0 m/m, and then dried in a fluidized dryer (hot air at 85°C) to obtain aspartame granules. As a control, 'type' aspartame crystal powder was used and granulated in the same manner. The physical properties of the obtained granules were compared with those of the original aspartame crystal powder, and the properties were as follows.

【table】

[Table] (Note) Specific volume Crude specific volume: JIS K 6721 specific gravity meter was used. It is expressed as the volume ratio to the weight of the contents filled in a 100 c.c. cylindrical container. Dense specific volume: Powder tester (manufactured by Hosokawa Iron Works KK)
-150 for 3 minutes using a tapping device of
It is expressed as the volume ratio to the weight of the confidential material filled in a 100 c.c. cylindrical container. Solubility Add 0.05 g of aspartame to 150 ml of warm water at 60°C while stirring (magnetic stirrer,
300R.PM) and measure the time until it disperses and dissolves in water. Dispersibility: The time it takes for aspartame to disperse in water. Solubility: The time it takes for aspartame to completely dissolve. That is, when aspartame in the '-type crystal form was used, it was difficult to form granules during granulation, and the granules broke and became pulverized during drying, making it impossible to obtain a product. When using crystalline aspartame, well-shaped granules are obtained, and their solubility is
It had physical properties that were much improved compared to the bulk powder used as the raw material, and had excellent handling properties with little scattering and good fluidity. * Obtained by drying aspartame crystal slurry, which was separated into solid and liquid using a centrifuge, for 2 to 3 seconds using a flash dryer. Example 2 '-shaped aspartame crystal powder※※600g and water
320 g was added and granulation was carried out in the same manner as in Example 1. The powder physical properties and solubility of the obtained granules were determined in Example 1.
When the type aspartame crystal powder obtained in the above was compared with the granules obtained using the aspartame crystal powder as a raw material, as shown in Table 2, they had almost the same quality characteristics.

[Table] ※※Aspartame crystal slurry separated into solid and liquid with a centrifuge was dried in an aerated dryer at a hot air inlet of 110°C for 1 hour (exhaust air 70-80°C). Example 3 Using aspartame crystal powder of type 3,
Water was added so that the water content of the product became 10 to 50%, and granulation treatment was performed in the same manner as in Example 1. Granulation properties and product physical properties were as shown in Table 3.

[Table] That is, if the water content of the mixture is less than 35%, it will not be granulated, and if it is more than 45%, it will be kneaded and will not pass through the screen. Good granules were obtained between 35 and 45% moisture. Then, within that range,
The higher the moisture content of the material, the smaller the specific volume and the higher the density. The solubility was better as the specific volume was smaller. Example 4 2.5 kg of aspartame crystal powder and 1.4 kg of water
were mixed and granulated using a granulator (manufactured by Fuji Sangyo KK), and the granulated product was dried using a fluidized fluid dryer in the same manner as in Example 1 to obtain aspartame granules. As a control, 'type' aspartame crystal powder was used and mixed and granulated in the same manner. The physical properties of the obtained granulated products were compared with those of the original aspartame crystal powder as in Example 1, and the properties were as follows.

[Table] (Note) Fluidity: ○ Good, × Bad Example 5 The separation and purification process of aspartame was performed by alcohol crystallization. Ethyl alcohol was used as the alcohol, and the alcohol concentration was adjusted to 40 w/w%. After crystallization, the slurry was centrifuged to remove the mother liquor. The adhesion rate of the crystal slurry scraped from the centrifuge to the mother liquor was 42%. Transfer 1 kg of the crystal mud to a kneader and mix with 60 g of water.
After continuing mixing for 15 minutes, the mixture was extruded and granulated using a screen with a diameter of 1.5 m/m, and then dried using a fluidized fluid dryer in the same manner as in Example 1. As a result, the molds and '
A product similar to that obtained when granulating aspartame crystal powder of the type was obtained.

[Brief explanation of drawings]

1 to 4 are powder X-ray diffraction patterns of the crystals of the present invention. Note that the vertical axis shows the diffraction intensity, arbitrary units, and the horizontal axis shows the diffraction angle, 2θ° (CuKα ray). Figure 1...type, figure 2...'type, figure 3...
...type, Fig. 4...'type.

Claims (1)

[Scope of Claims] 1. Water is added to α-L-aspartyl-L-phenylalanine methyl ester crystals so that the water content becomes 35 to 45%, and (1) they are mixed and granulated, and/or (2)
A method for producing dipeptide sweetener granules, which comprises passing the mixture through a screen with a diameter of 0.8 to 2.0 m/m and then drying it. 2. Claim 1, characterized in that the α-L-aspartyl-L-phenylalanine methyl ester is in a crystal form with an X-ray diffraction pattern as shown in FIGS. 1 and 2. A method for producing the dipeptide sweetener granules described. 3 After the above α-L-aspartyl-L-phenylalanine methyl ester is crystallized in an aqueous solution of methyl alcohol and ethyl alcohol with a concentration of 35% or more, a portion of the mother liquor is separated and has a water content of 35~
A method for producing dipeptide sweetener granules according to claims 1-2, characterized in that the granules are 45% crystalline sludge. 4 The above mixture has a PH value due to organic acids and amino acids.
4. A method for producing dipeptide sweetener granules according to claims 1 to 3, characterized in that the dipeptide sweetener granules are adjusted to 3.0 to 3.5. 5. The method for producing dipeptide sweetener granules according to claims 1 to 4, wherein the mixture contains 0.1 to 0.5% of a water-soluble surfactant.