WO2005020716A1

WO2005020716A1 - Aspartame solution

Info

Publication number: WO2005020716A1
Application number: PCT/CH2003/000587
Authority: WO
Inventors: Harald Meyer
Original assignee: Ajinomoto Switzerland AG
Current assignee: Ajinomoto Switzerland AG
Priority date: 2003-08-28
Filing date: 2003-08-28
Publication date: 2005-03-10
Anticipated expiration: 2006-02-28
Also published as: EP1657983A1; CN1826057A; AU2003250732A1

Abstract

Described is an aqueous solution that is highly concentrated in aspartame due to the presence of beta-cyclodextrin as solubility enhancing agent.

Description

Asparta e Solution

Technical Field

The present invention concerns an aspartame solution, in particular a highly concentrated aqueous as- parta e solution and uses thereof.

Background Art Aspartame is a high potential sweetener that for its sugar-like taste is broadly applied to sweeten food stuffs. One disadvantage of aspartame, however, is its low solubility in water of only about 1%. Cyclodextrins are known to act as solubility enhancers for several substances . The solubility enhancing effect is due to the formation of a 1:1 complex. Therefore, over the past years cyclodextrin derivatives, in particular specificly substituted cyclodextrins, have been developed that have enhanced solubility. Unfortunately such highly soluble cyclodextrin derivatives are not approved for use in foodstuffs. Thus, for foodstuff applications only the natural cyclodextrins may be used. In literature gamma-cyclodextrin is disclosed as best choice for enhancing the solubility of hydropho- bic substances. However, an attempt to noticeably enhance the solubility of aspartame by adding gamma-cyclodextrin was not satisfying. Disclosure of the Invention

Hence, it is a general object of the present invention to provide a high-concentrated aqueous aspar- tame solution suitable for foodstuff applications . Other objects of the present invention are - a method for producing an aqueous aspartame solution of the present invention, - the use of beta-cyclodextrin to produce an aqueous aspartame solution of the present invention, - the use of an aspartame solution of the present invention for improving the taste of beverages, in particular milk, - the use of an aspartame solution of the present invention in the production of fermented or not fermented milk products, - a beverage or foodstuff, in particular a milk derived beverage or foodstuff, comprising an aspartame solution of the present invention, - an aseptic bag comprising a solution of the present invention and its use in a liquid dosing and mixing apparatus . Now, in order to implement these and still further objects of the invention, which will become more readily apparent as the description proceeds, the aqueous aspartame solution of the present invention is manifested by the features that it comprises aspartame and beta- cyclodextrin . It has surprisingly been found that aspartame and beta-cyclodextrin have a synergistic effect resulting in highly concentrated stable solutions comprising about 15 - 17 % beta-cyclodextrin and about 5 % aspartame. In view of the synergistic effect, in a concentration range above the solubility of the single com- pounds, equimolar amounts should be used to ensure that no undissolved substances remain in the solution. In order to further stabilize the highly concentrated aspartame solution, it has been proved advantageous to remove possible crystallization inducing nucleating agents . Such removal can be performed by filtration with e.g. a 0.2μm-filter . Such filtration can simultaneously act as sterilization. The production of the highly concentrated aspartame solution can be performed in that the aspartame and the cyclodextrin are mixed, then dissolved in water and finally filtered. For the preparation of the solution of the present invention, cyclodextrin in usual food stuff quality is suitable. Aspartame in general is very pure and thus applicable. Nevertheless, also such very pure aspartame may contain undesired nucleating agents that preferably are removed by filtration. Such filtration, e.g. with a 0.2μm-filter, can simultaneously serve as sterilization. Another possibility to get sterilization is e.g. by pasteurization, in particular by heating the solution at a pH in the range of about 4.2 to 4.5, since in said pH-range the aspartame degradation is slowest. The production of the solution can be performed either at ambient temperature or at enhanced temperature. Enhanced temperature does not much reduce the time needed to get a solution, since stirring over a long time (up to 24 hours) is in any case preferred in order to ensure complete formation of the 1 : 1 complex. Suitable stirring methods are in particular mechanical stirring. The stirring intensity seems not to be critical. E.g. soft stirring (50 to 200 rpm) , in particular around 150 rpm, proved to be suitable. In the case of about equimolar amounts, the stirring, usually is performed until full dissolution (complex formation) is obtained. Presently preferred dissolution parameters are stirring for a short time, e.g. 10 to 20 min., in particular about 15 min. , at enhanced temperature of usually about 45°C to 55°C, in particular approx. 50°C, followed by stirring for up to about and often about 24 hours at low temperature of usually about 20 to 30°C, in particular at ambient temperature. The aspartame and/or the beta-cyclodextrin can be mixed as solids and the resulting mixture can be added to water or, preferably the water to the mixture. Or the aspartame and/or the beta-cyclodextrin can be suspended in part or all of the water and then mixed in the adequate ratio. The actual procedure chosen, however, should ensure that the cyclodextrin and the aspartame both remain as fine powders, i.e. have a large surface, since otherwise the dissolution is too slow. Further substances, in particular water soluble substances such as acids, colorants, stabilizers, an- tioxidants, vitamins, a ino acids, peptides etc., can be added during stirring. As soon as the dissolution has been completed, any not dissolved substances are preferably filtered off. A suitable filter has a pore diameter of about 2μm. By such filtration on the one hand all crystallization inducing nucleating agents are removed and also excess aspartame and/or cyclodextrin and on the other hand simultaneously sterilization is obtained. The inventive solution, in particular if pro- visions are made to ensure absence of nucleating agents, is very stable. At room temperature, the only problem is the known decomposition of aspartame that with time leads to a disturbance of the equilibrium resulting in the precipitation of beta-cyclodextrin. Such precipitated beta- cyclodextrin may then act as nucleating agent. Therefore, the inventive solution preferably has a pH in the range of about 4.2 to 4.5 in which aspartame - also in a complex with cyclodextrin - is most stable, and the solution should not be stored for more than 6 months . The decompo- sition rate of aspartame in the presence or absence of beta-cyclodextrin is about 6 % in 150 days at 20° and a pH of about 4.5. At very low temperature, e.g. 4°C, the beta- cyclodextrin has the tendency to crystallize. Due to the comparably small surface of such crystals, the crystallization can hardly be inverted. Thus, precipita- tion/crystallization at low temperatures should be avoided. Due to the high concentration of aspartame (about 500% of a cyclodextrin free solution) new applications are available. One of the most important applica- tions is in milk improvement. Hitherto, in hot countries with poorly developed cooling systems and/or high demands at purification methods (longtime heating) , milk is degraded rapidly. The degradation is perceived as an undesired off-taste of the milk. For masking said off-taste, flavors may be added. However, without sweet component, such supplementation will not be approved by the consumer. The supplementation with sugar is also not possible due to the large amount needed, the limited solubility of sugar and the lack of acceptance by some consumers because of the enhanced caloric content. Thus, for such application aspartame is the sweetener of choice provided that a sufficiently high- concentrated solution can be provided such that it can be dosed without inadmissibly diluting the milk. Such sufficiently concentrated solution has now been provided by the present invention. With the concentrated solution of the present invention, at most 1ml/l has to be added, often less. The advantage of an aspartame solution is that it can be packed in aseptic bags and - due to the liquid form - easily processed in sterile equipment. Any dusting, adherence to walls etc. known for pulverized aspartame is avoided thereby leading to a more constant dosing, less down-time due to maintenance of the equipment etc . One suitable apparatus is the FlexDos^® system of Tetra Pak^®, e.g. the FlexDos^® apparatus designated FDU 2000 or FDU 3000 as described in a prospectus marked ⁿ© 2003 Tetra Pak Arom Pak, Produced by Clavis, Lund, Code 8803en, Printed in Sweden . 2003-03 " . Such apparatus is available from Tetra Pak Arom Pak^®, Maskinvagen 5, SE- 227 30 Lund, Sweden. Further applications of the inventive solution are beverages in general, but also milk products such as fermented or not fermented milk products, e.g. yogurt .

Brief Description of the Drawing

The Figure shows the degradation over the time of aspartame in a 1 : 1 complex with beta- cyclodextrine at a pH of about 4.5 and at a temperature of 20°C.

Modes for carrying out the Invention

Highly concentrated aspartame solutions can e.g. be produced by using the following ingredients:

1. Ingredients

1.1. Aspartame : C1 H13 2O5 (Aspartyl phenylalanine methyl ester)

E Number: E 951

EINECS Number: 245-261-3

CAS Number: 22839-47-0

Molecular Weight: 294.3g/mol Solubility in water 20°C: 1% 1.2. Beta-Cyclodextrin:

C 2H70O35 (other names: Cyclomaltoheptaose, β-Schardinger Dextrin)

E Number: E 459 EINECS Number: 231-493-2

CAS Number: 7585-39-9

Molecular Weight: 1135.0g/mol

Solubility in water 20°C: 1.6%

1.3. Citric Acid (as Citric Acid Monohydrate) : C₅H₈0₇-H₂0

Ξ Number: E 330

EINECS Number: 201 069 1

CAS Number: 5949-29-1 Molecular Weight: 210.1g/mol

Solubility in water 20°C: 1630g/l

1.4. Purified Water

2. Formulation

Aspartame (from Ajinomoto) 5.0 % by weight

Beta-Cyclodextrin 17.0 % by weight Citric Acid^*' (optional) 0.03 % by weight

Water balance percentages for citric acid anhydrous

Preparation

Cyclodextrin, aspartame and optionally citric acid, were dry blended. Then purified water of 50°C was added. After stirring (approx. 150 rpm) for 15. min. the solution was let to cool down. A clear solution was obtained. Agitation at approx. 150 rpm was continued for 24h. The solu- tion became slightly opaque. A sterile filtration through a filter with 0.2μm pore width (use of prefilter recommended) was performed. For storage and transport a temperature in the range of 10 to 30°C, preferably of about 20°C, should be ensured.

4. Technical Data of Citric Acid Comprising Solution

Aspartame cone . : 5 % pH: app . 4.5

Density: 1.08 kg/1 at 20°C

Viscosity: 3 mPas (=centiPoise) - Brookfield Viscosimeter Spl/60rpm/20°C Refractometer : 21.9° Brix

Stability: app.1% Aspartame degradation in 1 month at 20° Storage: Ambient temperature, do not freeze

The aspartame (APM) degradation of high concentrated aspartame solution over the time and at 20°C was determined (see Figure) . During the 150 days during which degradation of aspartame was monitored, no destabilization of the solution due to "excess" beta-cyclodextrin was observed. After filtration, the aspartame solution prepared as described above, can directly be used or packed in aseptic containers, in particular bags; or it can first be further sterilized, e.g. by pasteurization, prior to use or packing, or a pasteurization can be performed on the already filled bags . The bags can be directly used or stored and/or shipped, preferably at temperatures of about 10 to 30°C, much preferred about 20°C. A preferred method for use is that the bag is fixed to a suitable dosing and mixing apparatus such that solution out of the bag is dosed to a larger flow of basic foodstuff, e.g. beverage or, in particular, milk. The milk can in addition be supplemented with other additives such as flavors. It can suitably be sterilized prior to the addition of the aspartame solution and/or in a further purification step, e.g. a pasteurization step, after the supplementation and optional packing into bags for distribution to food markets etc. In yogurt production, the aspartame solution of the present invention can e.g. be added at the same point as the flavors . The high-concentrated aspartame solution of the present invention can be used for the production of a broad variety of beverages and foodstuffs . Thus beverages and foodstuffs comprising aspartame and beta cyclodex- trine, in particular in equimolar amounts, are also an object of the present invention. The highly concentrated aspartame solution of the present invention can also be used as a liquid house- hold sweetener for sweetening hot or cold beverages, desserts etc . While there are shown and described presently preferred embodiments of the invention, it is to be distinctly understood that the invention is not limited thereto but may be otherwise variously embodied and practiced within the scope of the following claims.

Claims

1. Aqueous aspartame solution comprising aspartame and beta-cyclodextrin.

2. The aqueous aspartame solution of claim 1, wherein the aspartame and the beta-cyclodextrin are present in equimolar amounts .

3. The aqueous aspartame solution of claim 1 or 2, wherein the aspartame concentration is about 5%.

4. The aqueous aspartame solution of anyone of claims 1 to 3 wherein the beta-cyclodextrin concentration is about 15 to 17%.

5. The aqueous aspartame solution of anyone of claims 1 to 4 further comprising at least one water soluble additive selected from the group consisting of acids, colorants, stabilizers, antioxidants, vitamins, a ino acids, peptides, and mixtures thereof.

6. A method for producing an aqueous aspartame solution of anyone of claims 1 to 5 comprising the steps of mixing aspartame, beta-cyclodextrin and water and stirring until maximum dissolution is obtained.

7. The method of claim 6 , wherein the aspartame and the beta-cyclodextrin are mixed in equimolar amounts .

8. The method of claim 6 or 7 , wherein the solution is filtered, in particular through a filter with 0.2 μm pores.

9. The method of anyone of claims 6 to 8 , wherein the aspartame and/or the beta-cyclodextrin is added as suspension in at least part of the water.

10. The method of anyone of claims 6 to 9 , wherein the amounts of aspartame and beta-cyclodextrin and water are such that they result in an at most saturated solution, preferably in a saturated solution.

11. The method of anyone of claims 6 to 10, wherein the stirring is performed for a short time, preferably 10 to 20 min., in particular about 15 min., at en- hanced temperature, preferably about 45°C to 55°C, in particular approx. 50°C, followed by stirring for up to about 24 hours at lower temperature, preferably 20 to 30°C, in particular at ambient temperature.

12. Use of beta-cyclodextrin to produce an aqueous aspartame solution of one of claims 1 to 5.

13. Use of an aspartame solution of one of claims 1 to 5 for improving the taste of beverages, in particular milk.

14. Use of an aspartame solution of anyone of claims 1 to 5 in the production of fermented or not fermented milk products.

15. A beverage or foodstuff, in particular a milk derived beverage or foodstuff, comprising aspartame and beta-cylodextrin.

16. The beverage or foodstuff of claim 15, comprising aspartame and beta-cyclodextrin in equimolar amounts .

17. An aseptic bag comprising a solution of one of claims 1 to 5.

18. Use of an aseptic bag of claim 17 in a liquid dosing and mixing apparatus .