AU683713B2 - Stable aqueous dipeptide suspensions - Google Patents

Description

WO 95115697 PC(''S94/140801 Stable Aqueous Dipeprtde Susrensions Background of the Invention The present invention relates to the preparation of stable suspensions of high intensity sweeteners for use in foods and beverages and the compositions r-"pared thereby. More specifically, the present iention relates to stable dipeptide based sweeteners that are formulated as stable, easy to use suspensions for use in the food and beverage industries.

Aspartame (APM) is a well known dipeptide sweetener manufactured and sold by The NutraSweet Company of Deerfield, Illinois, as NutraSweet Brand sweetener. Additionally, there are some foreign manufacturers of aspartame. When used herein the term "aspartame" or "APM" refers to alpha-L-aspartyl-Lphenylalanine methyl ester and its' salts and metal complexes as taught in U.S. Patent No. 3,492,131 to Schlatter. Salts and metal complexes of APM are disclosed in U.S. patents 4,439,460; 4,029,701; _.3,714,139; 4,031,258; and 4,448,716 all of which are incorporated herein by reference.

A major application for aspartame is as a low calorie sweetener in the food and beverage industries.

Aspartame is sold in bulk to the various beverage manufacturers who must then repackage the sweetener and distribute it to their various bottlers. Aspartame in bulk is commercially available as both powder and granulated forms. Aspartame powder has low bulk density and good dissolution properties yet, due to its lower bulk density and small particle size, is readily air-borne and may have dusting and flow problems. The granular form has a higher bulk density and possesses good flow properties but does not always -I I I I I~ WO 95/15697 P('TIl'SU941408( instantaneously dissolve. These properties ca. result in product losses and metering problems, a need for expensive packaging and overall shipping and handling inconveniences.

The present invention improves the overall stability and flowability of aspartame during shipping and storage. The dipeptide nature of the compound, render it highly susceptible to degradation by heat and other chemicals by hydrolysis of the its peptide bonds.

Long term storage or storage in areas cf high temperatures often result in the loss of much of its sweetness. Moreover, the powder itself is hard to handle as some becomes lost in the environment as "dust". It has been determined that in the beverage industry some of the bulk aspartame powder is lost as dust in the air during handling and manufacture. When one is dealing in tons of aspartame per year, these are considerable losses which if cut down will result in major cost reductions. The present invention eliminates this problem.

Finally, another advantage of the stabilized APM suspensions of the present invention is the dissolution and dispersion of the suspensions in solution as compared with the unprocessed aspartame powder. During beverage manufacture, aspartame powder when mixed with the soft drink liquid has a tendency to float on the surface of the liquid and adhere to the sides of the container in which it is mixed. In non-acidified liquids, both the powder and granular forms tend to clump into a sticky mass and are not easily dispersed and dissolved. Since the high tech beverage manufacturing facilities of today require precise metering of the liquid components of the beverage to be made, such clumping is entirely unacceptable. This requires the use of equipment for agitation or stirring r Ir WO 95/15697 PCTIUS94/14080 -3to mix the powder into the liquid resulting in additional processing steps and costs of manufacture.

For liquid and semi-liquid applications a high concentration aspartame (APM) suspension can have many advantages over powder or granular APM. For example, it may be more convenient and economical for carbonated soft drink companies to have an all liquid production system to avoid the costs, labor and problems relating to handling solids, particularly in powder form.

However, both APM's aqueous stability and solubility have prevented the development of such a product.

United States Patent No. 4,722,844 to T. Ozawa et.

al. teaches the preparation of aqueous APM suspensions which are asserted to be stable both chemically aid physically. In water, like most crystalline materials, APM particles sink and settle since APM's specific gravity is significantly greater than that of water.

To obtain physically stable APM suspensions, this patent teaches the addition of a viscosity or specific gravity increasing component, such as food gums and polysaccharides. The patent discloses physically stable 2-5% APM suspensions in sugar syrups, such as isomerized sugar and sorbitol syrups. The aspartame suspensions of Ozawa et. al. '844 use an aqueous vehicle that is high in sugar, polysaccharide or food gum content, i.e. over 50%, and low aspartame content.

Such a product will not be acceptable however, for use in most food applications.

United States Patent No. 4,007, 288 to Glicksman et. al. discloses a readily soluble sweetening composition for use in foods and beverages wherein the aspartame is first solubilized with a bulking agent such as dextran or some other hydrolyzed starch material and the solution is then vacuum drum dried to a composite powder of sweetener and bulking agent.

L I WO 95/15697 PCT/US94/14080 -4- Unized States 2atent No. 4,631 ,195 to Coil--c-'0 et.

dscioses a notIner at temptc szabi- ing asp a rzae for cookina and baking uses wacrerby tn'-e ascarcame is co-dri-ea. witn polygucs or Uoynlts Patent: No. 4,619,83 to Anderson teaches a rapid>171 s l-te dry beveragre mix in which ascarae is drv mixed w:t-h a discerslon o'f foocd ac'ds, flow condit~nr and rmat dexr rin.

Finally, United States Pa=tenz No. 4 CC'456 a-Iso t0 o G-Iicksrnan et. al. Zeaches sweetening corcs~tiocns in which asnarcame is mixed 4 n an acueous sclution orf a bukina aaent cortvorisima an organ--- acid, hv-drc lyzed starch materIals and suaars wherein the solution is szrav dried to formn a fine, aaaolcrera-ed APM/bulkina aaent powder. None of the- por-or arc however, teach-es a physically stable aspartai-e susnens-cn in wacer with a hichI AP-cncent :cr easyv use, handlino and stor-age for a broad ranae of liauid and en---d ziccos umayof the Invention :in a first aspect, the present invention provides a shelf-stable sweetener suspensionL- comprising an aqueous suspension of alpha-L-aspartyl-L-phenl-alaline methyl ester, in a concentration of from about 10% to about 70% by weight of the total weight of the suspension, and a stabilizing flow agent, in a concentration of from about 0.001%- to about 0.6%; by weight of the total weight of the suspension, wherein said stabilizing flow agent is selected from the group consisting of sodium carboxym,-ethyl cellulose, dexc-ran, gum arabic, carrageenan, xanznan gum, cruar gum, <q~>hydroxypropyl methylcellulose, wethylicellulose, peccin, locust bean gum, sodium alginat, prcpylene glycol alginate, Lo caramel and mixtures thereof.

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~BL~DLB ~II_ II_- I WO 95/15697 PCT/US94/14080 -4A- In a second aspect, the present invention provides a method for the preparation of a shelf stable dipeptide sweetener suspension comprising: mixing-powdered or granular alpha-L-aspartyl-Lphenylalanine methyl ester with a stabilizing flow agent in water to form a suspension; wherein said alpha-L-aspartyl-L-phenylalanine methyl ester is present in the suspension at a concentration of from about 10% to about 70% by weight of the total weight of the suspension, said stabilizing flow agent is present in the suspension at a concentration of from about 0.001% to about 0.6% by weight of the total weight of the suspension, and said stabilizing flow agent is selected from the group consisting of sodium carboxymethyl cellulose, dextran, gum 15 arabic, carrageenan, xanthan gum, guar gum, hydroxypropyl methylcellulose, methylcellulose, pectin, locust bean gum, sodium alginate, propylene glycol alginate, caramel and i mixtures thereof.

In a third aspect, the present invention provides a S 20 shelf stable sweetener composition comprising an aqueous suspension of about 50% by weight alpha-L-aspartyl-Lphenylalanine methyl ester and about 0.1% by weight sodium carboxymethyl cellulose.

In preferred embodiments of the first and second aspect 25 of the present invention, the suspension/method is characterized in that said alpha-L-ascartyl-L-phenylalanine methyl ester is present in an amount of from about 20% to about 35% by weight of the total weight of the suspension; or in further comprising an emulsifier, which may be selected from the group consisting of Folysorbate, lecithin and mixtures thereof.

In further preferred embodiments of the first aspect of <.'RA'LN the present invention, the suspension is characterized in 5 1 C- I ~1 -r WO 95/15697 PCT/US94/14080 -4Bthat said alpha-L-aspartyl-L-phenylalanine methyl ester is comprised of particles having a size of no greater than 100 standard U.S. mesh; or in having a viscosity from about 150 mPas. to about 1750 mPas.

In a further preferred embodiment of the second aspect of the present invention, the method is characterized in that said alpha-L-aspartyl-L-phenylalanine methyl ester is first mixed into water, and said stabilizing flow agent and emulsifier are subsequently added to the water and alpha-Laspartyl-L-phenylalanine methyl ester mixture.

Thus, the present invention provides a physically stable aspartame liquid composition in which high concentrations of aspartame (APM) are achieved in suspension 15 using a trace amount of a stabilizing flow agent in the composition. APM suspensions containing concentrations of from about 10% to about 70% in water by weight are stabilized under long term storage conditions and provide superior handling and dissolution characteristics for use in beverages 20 and other liquid applications since the crystalline problems inherent in APM dry powder such as poor flowability, dustiness and poor dissolution are no longer present.

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Ip I I WO 95115697 PCT/US94/14080 Brief Description of the Drawings Figure I is a line graph plotting the percent of dissolved aspartame with a trace amount of carboxymethyl cellulose in water as a function of time.

Figure II is a line graph comparing the dissolution rate of the aspartame suspensions of the present invention versus that of pure aspartame alone in water Figure III is a graph depicting the effect of the hydrocolloid additives on the viscosity of APM suspensions.

Figure IV is a flow curve of aspartame suspensions using sodium carboxymethyl cellulose.

Figure V is a graph depicting the fluidization of APM suspensions using a hydrocolloid.

Detailed Description of the Invention For liquid and semi-liquid applications, a high concentration aspartame (APM) solution can have many advantages over powder and granular APM as discussed, supra. For example, it may be more convenient and economical for carbonated soft drink companies to have an all liquid production system to avoid the costs, labor and problems relating to handling solids.

However, both APM's aqueous stability and solubility characteristics have prevented the development of such a product.

The present invention is a relatively pure aspartame liquid suspension with an APM concentration of from about 10% to 70% by weight that is both physically stable under long term and adverse storage conditions as well as providing greater ease in handling than bulk aspartame crystalline powder. The problem with most APM suspensions of high aspartame concentrations, i.e. is that they become highly I I III WO 95/15697 PCT/US94/14080 -6viscous, sticky and not sufficiently flowable for the required applications.

By the term "suspension" one refers to a system whereby very small particles (solid, semi-solid or liquid) are more or less uniformly dispersed in a liquid or gaseous medium. If the particles are small enough to pass through a filter membrane the system is colloidal. If the particles are larger than this, they will tend to precipitate and sink since they are la heavier than the surrounding solution. If lighter than the solution however, they will agglomerate and rise to the surface.

All of the aforementioned problems are surprisingly overcome in the present invention through S: 15 the incorporation of a small amount of a stabilizing flow agent selected from the group consisting of sodium carboxymethyl cellulose, dextran, gum arabic, carrageenan, xanthan gum, guar gum, hydroxypropyl methyl cellulose (HPMC), methylcellulose, pectin, locust bean gum, sodium alginate, propylene glycol alginate, caramel and mixtures thereof.

Trace amount of an emulsifier or wetting agent such as polysorbate (polyoxyethylene fatty acid ester) or lecithin may also be incorporated to improve the suspensions' dissolution and stability characteristics. The stabilizing 25 flow agent may be effectively incorporated in the suspensions in amounts of from about 0.001% to about 0.6% of the total weight of the suspension. Levels exceeding 0.6% may continue to reduce the viscosity of the suspension but to a less effective degree and thereby provides a diminished return.

Although asparame powder is sparingly soluble In water, it is possible to make a suspension of AFM in water by itself. For example, suspensions up to '1 II WO 9S/1S697 PCT/US94/14080 o r r r r r -7can be made in water, however, this suspension is a very viscous foam or paste which does not lend itself to fluid processing operations like pumping, mixing, etc., which are prevalent in the beverage and dairy industries. This foam is not stable and seDarates into 3 phases, a foam/air layer, water and a layer of APM crystals that has settled. The addition of the stabilizing flowability agent of the present invention in a trace amount (approx. during the formation of the suspension makes it stable which lends itself well to unit operations in fluid processing for the food and beverage industry.

The addition of the stabilizing flow agen:.- to an aqueous suspension of aspartame surprisingly alters the flow 15 characteristics of the suspension to a more fluid form exhibiting pseudoplastic flow behaviour with enhanced dissolution properties and stability. This is of particular value to applications involving fountain dispensed carbonated soft drinks where aspartame is prone to accelerated degradation because of the low pH environment created by the other fountain components.

When mixed in a suspension with the stabilizing flow agent, aspartame levels of from apprcximately to about 70% by weight of the total weight cf the 25 suspension is achievable. Preferably, said asparame is incorporated in amounts of from about 20% to about by weight and most preferably in an amount of from about 20% to about 35% by weight of the en:ire suspension.

Viscosity values for suspensins can be measured using a Haake Rotoviscometer Model 7-500 (Saddlebrook, in which a 'bob' rotates in a vessel crntan ng the susoension to be measured. -s the bob rotates, She speed is measured as the shear rate an :he o' .s 1

(C-V

-II I I WO 95/15697 PCT/US94/14080 -8suspension is sheared and exerts a resistance to the movement of the bob that is measured by the stress which is a direct function of its viscosity; i.e. the greater the viscosity, the greater the resistance.

This is the shear stress plotted on the Y-axis of Figures III-V Viscosity (ETA) is measured by the slope of the line plotted by the shear stress v. shear rate.

This is called the flow curve and the viscosity values are defined in terms of milli-Pascal seconds (mPas).

Referring now to the graph of Figure I, it is clearly shown just how quickly the compositions of the present invention dissolve in water. A 50% APM suspension with 0.2% carboxymethyl cellulose is almost completely dissolved within thirty (30) seconds.

Figure II compares the rate of dissolution of the APM suspension (with 0.2% CMC) versus that of pure APM powder in distilled water at 100C. Again clearly, a greater percentage of APM becomes dissolved in solution at a much faster rate using the compositions of the present invention than that of APM alone.

Traditionally, hydrocolloids have been used to increase the viscosity of fluids. In the present case, the addition of hydrocolloids turns the foam into fluid, the viscosity decreases, and the APM suspension becomes fluidized thereby becoming more manageable.

Microscopy data shows that the APM crystals surround the air bubbles in a foam and that crystals are floating or moving freely in a liquid suspension. This phenomena may be explained by the fact that APM is dipeptide with a hydrophobic group in its structure.

When this is dissolved in water, the water is organized and further addition of the crystals then creates the foam with the aspartame stabilizing the foan. Addition of a very hydrophilic polymer like carrageenan or sodium carboxymethyl cellulose (sodium CMC) frees up ~I 9 __sl~l~ll~ WO 95/15697 PCT/US94/14080 -9the water and allows more APM to be added to the system. The suspending properties of sodium CMC are not unknown, however, the fluidizing effect it has on the APM suspension is truly surprising and unexpected.

Referring now to Figure III, the effect of some selected hydrocolloids on the viscosity of APM suspensions is compared to a control 30% solution of pure aspartame. ETA, i.e. viscosity of the suspension ,is plotted as a function versus the shear rate of the suspensions. The greater the slope of the line, the greater the breakdown and flowability of the system.

As can be seen from the graph, suspensions comprising aspartame with 0.2% sodium carboxymethyl cellulose or 0.2% Viscerin (carrageenan) maintain viscosities that break down with the application of greater shear than that of the 30% APM control. Therefore, the suspensions with the additional hydrocolloid excipient were of a lower viscosity than the con rol indicating the flowability of these suspensions is also far greater.

Figure IV on the other hand showr the flow curve of three APM-CMC suspensions at 25 0 C rough a comparison of the compositions' shear stress as plotted against its shear rate. Again, flowability is measured in terms of the slope of the different curves and as expected, the 30% APM suspension displays far quicker breakdown at a greater rate than the 40% APM suspension which is greater than that of the 50% APM suspension.

Nevertheless, the 50% APM-CMC suspension does display substantial breakdown with increasing shear rate thereby proving that even high APM concentrations of the present invention are flowable and pourable and useful in the fluid and semi-fluid applications of the food and beverage industry.

Finally, Figure V compares the fluidability of a MOMOM-OW- WO ,95/15697 PCT/US94/14080 control 30% APM suspension with that of two suspensions of the present invention comprising APM with trace amounts of two different hydrocolloids.

Again, the rate of shear stress, the viscosity, is far greater with respect to the control than the two suspensions of the present invention. Here, the shear exerted against the system is encountering far greater resistance from the control (as shown by the height of the control graph line) than the other two suspensions.

Hence, the compositions of the present invention are far more fluid and consistent in their texture.

Without being bound to any theory, it is believed that the addition of the stabilizing flow agent prevents the formation of foam, the air entrapment by APM crystals and forms a fluid suspension of APM crystals in water with little or no air entrapment. In light micrographs of the foam APM in water, the crystals surround the air bubbles whereas in the suspension made with stabilizing flow agents, the crystals are literally moving around in the continuous 20 water phase.

The present invention also provides a method of preparing the physically stable and flowable APM suspensions. The desired amount of aspartame for a given S concentration in either powder or granular form may be 25 dispersed in water, either with or without the stabilizing flow agents using a standard intense rotary mixer. The preferred aspartame for use is a powder form of crystalline particles with a size of no greater than 100 standard U.S.

mesh. Aspartame granules and purified wet aspartame precipitate formed as a wet cake may also be used, provided they are mixed well into solution. The flow agent may be mixed into the aspartame powder or precipitate prior to solubilization or may be added to all three types cnce 1 *1 i v ~1~ WO 95115697 PCT/US94/14080 -11in solution.

Aspartame powder or granules are added slowly to water in a kettle and mixed using a high shear mixer in order to break up the larger particles. The stabilizing flow agent such as sodium CMC is added along with the powder. This helps in reducing the viscosity and allows for the addition of more APM. If preferred, sodium CMC can also be added to the water first and thoroughly dispersed prior to the subsequent addition of the APM to make the suspension.

The greater the concentration of aspartame in the suspension, the greater the viscosity of the suspension. Obviously, suspensions of long term stability will be more highly viscous than those of short term stability. Generally, the preferred viscosity values for the suspensions of the present inventions should range from about 150 mPas. to about 1750 mPas. and most preferably from about 150 mPas. to about 750 mPas. at 50 1/s shear rate when measured in the Haake Roto-viscometer at The flowable APM suspensions of the present invention may have many applications and can replace powder and granular APM in all liquid or semi-liquid food uses. In particular, the suspensions will provide a shelf stable product that is easily handled and readily incorporated into soft drinks, juices, dairy products and other beverage applications. Its high rate of dissolution and chemical stability will be particularly beneficial in fountain dispensed soft drink applications. It can also be used as an excellent table top sweetener with its superior dust free, rapid dispersion and dissolution properties.

The fluid APM suspensions of the present invention are an excellent sweetener source in "high tech" continuous beverage manufacturing plants employing I I i LI WO 95115697 PCTJUS94/14080 -12computer controlled valves that require precise delivery and mixing of liquid ingredients or components of the beverage. The APM suspension mixes easily with water or other sweetening agents such as high fructose corn syrup, liquid sucrose and/or fructose with minimal agitation or mixing and can be used in the manufacture of diet beverages in combination with caloric sweeteners.

The following examples are provided to better describe and disclose several embodiments of the present invention. They are for illustrative purposes only however, and it is recognized that minor variations and changes may be made with respect to the ingredients or process parameters that differ from those set forth below. These are still considered to fall within the spirit and scope of the present invention however, as recited by the claims that follow.

Example I A number of APM suspensions at 30% concentration were prepared using the stabilizing flow agents of the present invention comprising the following food polymers, hydrocolloids and gums in an amount of approximately 0.2% by weight of the total weight of the suspension. The flow curves of the suspensions were generated using the Haake Rotoviscometer Model VT500 at 250C using a MV1 sensor. The viscosity at 54 1/s is reported.

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WO 95/15697 PCTIUS94/14080 -13- Viscosity at Polymer Flow Agent 54 shear rate Carrageenan 32 Sodium Alginate 88 Xanthan gum 63 Sodium cart)xymethyl cellulose 111 Locust bean gum 519 Guar gum 193 Pectin 1512 Gum Arabic 679 Propylene glycol alginate 18 Caramel DS #400 166 A combination of polymer flow agents can also be used to make fluid 30% APM suspensions in water as shown below: Viscosity at Polymer Flow Agent 54 shear rate 0.2% Carrageenan 0.05% Xanthan 58 0.2% Carrageenan 0.05% Locust bean gum 68 0.2% Carrageenan Guar gum 43 0.2% Carrageenan 0.05% Sodium carboxymethyl cellulose 64 Samples of the above suspensions (50 ml.) were placed in test tubes and spun in a table-top centrifuge for fifteen (15) minutes at 50 g. After this time, all suspensions exhibited less than 2.0% sedimentation in the tubes.

Example II Stable APM suspensions were incorporated as the sweetener in fountain dispensed diet beverages and carbonated soft drinks (CSD).

Diet concentrates for fountain dispensed beverages need a stable high intensity sweetener since the distribution of the concentrate takes an average of days in distribution before it is hooked to a dispensing unit. The pH of the concentrate is below APM degradation in such applications is well known in the beverage industry. There are two modes of delivering the beverage concentrate to the fountain I I WO 95115697 PCT/US94/14080 -14unit: 1. A bag or a box container, typical size gallons.

2. A pressurized cylinder.

The preparation of a stable suspension with enhanced dissolution characteristics makes it possible to use APM in fountain dispensed drink applications.

Stable APM suspensions can be used in such applications where the suspension is stored separately from the diet drink/beverage concentrate in a separate unit. A required amount of the suspension (approx. 110 ml. of 50% APM for 5 gallon concentration) can be injected into the concentrate prior to attachment to the fountain dispenser. The injected APM dissolves rapidly in the concentrate within 30 seconds of introduction in the container under quiescent conditions with minimal external agitation providing the necessary sweetness when the beverage is dispensed from the fountain unit.

Food grade emulsifiers or wetting agents such as polysorbate 60 or lecithin may be added to the suspension to further enhance the dissolution and stability.

Example III A 50% liquid APM suspension containing 0.2% CMC was spray dried in a Niro spray drier with a centrifugal head. The inlet temperature was 160C and the outlet temperature was 100 0 C. The resulting powder was then easily reconstituted into a suspension. The powder can also be agglomerated using standard spray drying and agglomeration technology. The wet cake (described earlier) can be fluidized using the polymer flow agent and spray dried into a powder.

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Claims (12)

1. A shelf-stable sweetener suspension comprising an aqueous suspension of alpha-L-aspartyl-L-phenylalanine methyl ester, in a concentration of from about 10% to about 70% by weight of the total weight of the suspension, and a stabilizing flow agent, in a concentration of from about 0.001% to about 0.6% by weight of the total weight of the suspension, wherein said stabilizing flow agent is selected from the group consisting of sodium carboxymethyl cellulose, dextran, gum arabic, carrageenan, xanthan gum, guar gum, hydroxypropyl methylcellulose, methylcellulose, pectin, locust bean gum, sodium alginate, propylene glycol alginate, caramel and mixtures thereof.

2. The shelf stable sweetener suspension according to claim 1, wherein said alpha-L-aspartyl-L-phenylalanine methyl ester is present in an amount of from about 20% to about by weight of the total weight of the suspension.

3. The shelf stable sweetener suspension according to 20 claim 1 or 2 further comprising an emulsifier.

4. The shelf stable sweetener suspension according to claim 3, wherein said emulsifier is selected from the group consisting of polysorbate, lecithin and mixtures thereof. The shelf stable sweetener suspension according to any one of claims 1 to 4, wherein said alpha-L-aspartyl-L- phenylalanine methyl ester is comprised of particles having a size of no greater than 100 standard U.S. mesh.

I WO 95/15697 PCT/US94/14080 -16-

6. The shelf stable sweetener suspension according to claim 5, wherein said suspension has a viscosity from about 150 mPas. to about 1750 mPas.

7. A method for the preparation of a shelf stable dipeptide sweetener suspension comprising: mixing powdered or granular alpha-L-aspartyl-L- phenylalanine methyl ester with a stabilizing flow agent in water to form a suspension; wherein said alpha-L-aspartyl-L-phenylalanine methyl ester is present in the suspension at a concentration of from about 10% to about 70% by weight of the total weight of the suspension, said stabilizing flow agent is present in the n suspension at a concentration of from about 0.001% to about 0.6% by weight of the total weight of the suspension, and 15 said stabilizing flow agent is selected from the group o consisting of sodium carboxymethyl cellulose, dextran, gum arabic, carrageenan, xanthan gum, guar gum, hydroxypropyl methylcellulose, methylcellulose, pectin, locust bean gum, sodium alginate, propylene glycol alginate, caramel and 20 mixtures thereof.

8. The method according to claim 7, wherein said alpha-L-aspartyl-L-phenylalanine methyl ester is present in an amount of from about 20% to about 55% by weight of the total weight of the suspension.

9. The method according to claim 7 or 8 further comprising an emulsifier. The mechod according to claim 9 wherein said emulsifier is selected from the group consisting of RA %\polysorbate, lecithin and mixtures thereof.

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11. The method according to claim 9 or 10, wherein said alpha-L-aepartyl-L-phenylalanine methyl ester is first mixed into water, and said stabilizing flow agent and emulsifier are subsequently added to the water and alpha-L- aspartyl-L-phenylalanine methyl ester mixture.

12. A shelf stable sweetener composition comprising an aqueous suspension of about 50% by weight alpha-L-aspartyl-L- phenylalanine methyl ester and about 0.1% by weight sodium carboxymethyl cellulose. DATED this 20th day of August 1997 C S.C.o CC *r *o C THE NUTRASWEET COMPANY, By its Patent Attorneys, E. F. WELLINGTON CO.,, By; (Bruce Wellington) z A/KA/4248 I I