IE44797B1 - Sweetening composition and method for the preparation thereof - Google Patents

Abstract

L-aspartic acid derivatives typified by L-aspartyl, Lphenylalanine methyl ester (APM) in crystalline form are agglomerated by a minor weight percent of a like solution serving as a permanent aggregating matrix at the spaced points of contact in a random distribution of the crystals whereby they are assembled and immobilized to a free flowing form for use in dry food mixes.

Description

The present invention relates to a process for the preparation of artificially sweetened comestibles and, more particularly, to a process whereby the class of L-aspartic acid derivatives that are sweet are effectively converted to a free flowing mixable and highly soluble sweetening •5 composition.

The members of the sweetening class of L-aspartic acid derivatives such as the dipeptide L-aspartic acid ester of L-phenylalanine, i.e., APM aforesaid, are characteristically less soluble than would be prefen-red for a so-called instant comestible like a beverage mix containing the artificial sweetener. Accordingly, attempts have been made to render the compounds in this class more readily dispersible and soluble such as by subdividing them and thus improving their rate of solubility, as well as their rate of dispersibility. Attempts at subdivision of the crystalline particles of such compounds to enhance the rate of solubility have not been too successful and alternative means have been employed to effectively improve the rate of dispersion and hence the overall rate of solubility. One common problem of such compounds appears to be their electrostatic properties; as recovered in crystalline form, they possess an inherent zwitterion capacity; 4797 indeed as long as the compounds retain their identity as sweeteners it appears that they possess this capacity. Comestibles such as beverage mixes containing food acids, and powdered flavouring and/or colouring agents, when commingled with the artificial sweetener will have erratic flow properties due to the electrostatic properties of the sweetener. Also, such mixes are prone to dusting and are not free flowing compared to the more flowable active ingredients which characterize the mix; the consequences are irregularities or even useless beverage and other comestible recipes. Attempts at ameliorating these effects such as by screening are not effective since such attempts at subdivision are not permanent since the sweetening compound particles reaggregate under the influence of their inherent electrostatic charges.

It would be desirable to have a form of L-aspartic acid-derived sweetener which is readily blendable and flowable and which has a high rate of solubility and dispersibility. Preferably, such a compound should be blendable with flavouring and colouring ingredients, or should itself impart flavouring and colouring while at the same time being a stable sweetener.

We have now developed a process whereby discrete crystals of L-aspartic acid derivative sweetening compounds meeting the foregoing requisites are produced by employing a minor amount of the compound per se in solution as a medium to aggregate the crystals thereof in an immobilized state, the crystals being assembled randomly at spaced points of contact by the dried solution of the sweetening compound.

Accordingly, the present invention provides a process for producing a flowable dry sweetening composition which comprises admixing crystalline particles of an L-aspartic acid-derived sweetening compound with an amount of water sufficient either (a) to form a mixture of undissolved compound particles therewith and to cause a minor amount of the compound particles to be dissolved by the water to form an agglutenating solute, milling the compound particles admixed with water to a uniform, cluster-free slurry, causing the'^esulting solute solution to be distributed throughout the remaining undissolved compound particles while causing the particles to arrange themselves randomly with respect to one another, and drying the solution to immobilize the particles in the random arrangement thereof at spaced paints 44787 of contact through the intermediation of the redried compound, the sweetening composition consisting essentially of the particles immobilized by the redried compound, or (b) to form a semi-moist meal or dough and to cause a minor amount of the compound particles to be dissolved by the water to form an agglutinating solute which enables the moist mixture of crystalline solids to be converted into a handleable mass, shaping and subsequently drying and grinding the mass to immobilize the particles in the random arrangement thereof at spaced points of contact through the intermediation of the redried compound, the sweetening composition consisting essentially of the particles immobilized by the redried compound.

In carrying out the process of the invention according to alternative (a) the sweetening compound crystals are preferably subdivided by hydro-milling than to a uniform particle size upon which some crystals will be dissolved and form agglutinating solutes. This hydromilTed slurry, preferably at a reduced temperature at which solution is minimized, is then dried such, as by spray drying droplets produced by pumping the slurry through an atomizing nozzle- the droplets advantageously dry in a form whereby the subdivided discrete crystals nest with one another while a part of the droplet and are permanently bound to one another by the solute sweetening compound at their points Of contact, so that when the droplet is recovered as a dry powder a permanent agglomerate of sweetening compound in a free flowing, rounded form is obtained.

In alternative (b) the sweetening compound is converted into a semimoist meal or dough consistency produced by combining limited quantities of water and the sweetening compound in crystalline form, whereby the water partially dissolves a portion of the sweetening compound forming an agglutinating solute which enables the moist mixture of crystalline solids to be converted into a handleable mass, as by extruding at room temperature, which extrudate or otherwise-shaped mass can be dried and subsequently ground- the aggregated particles wjll possess the same characteristic random nesting of crystalline sweetening compounds adhering at their spaced points of contact through the intermediation of redried sweetening compound acting to bridge the crystalline particles into immobilized granules, In this aspect of the invention the compound particles are preferably distributed in an amount of water which forms a doughy, shape-retaining meal : 4 44797 having the solution of sweetening compound distributed therethrough to agglutinate the particles in the random arrangement. More preferably, the meal is shaped and sub-divided.

The alternative embodiments of the process of this invention and the 5 product produced thereby, will be chosen dependent upon the intended use of the product. The preferred spray dried form of particles having a very free blowing, high rate of solubility are preferred for beverage uses, whereas in other applications it may be practical to resort to the dough-forming techniques to be hereinafter described wherein a more granular form of particulate structure will be suitable.

The invention may be used- in the production of sweetening compositions from a broad class of L-aspartic acid derivatives which will be categorized as follows:(1) The methyl esters of L-aspartyl-2, 5-Dihydro-L-phenylalanine; L-aspartyl-L-{l-cyclohex-l-en)-alanine; L-aspartyl L-phenylglycine; L-aspartyl-L-2, 5-dihydro-phenylglycine; (2) methyl-L-aspartyl-L-alpha-phenylglycinase and its salts. (3) Lower alkyl esters of L-aspartyl-L-(beta-cyclohexyl)-alanine disclosed in South Africa Patent No. 5,695,910; (4) Those alkyl esters classed as alpha-L-or DL-aspartyl-L or DLsubstituted glycines described in Netherlands Patent No. 7,007,176; (5) Those hvdroqenated dipeDtide ester sweeteners such as L-asparagio-O-etherified serine methyl esters described in French Patent No. 2,105,896; (6) Those aspartic acid peptide esters havinq the formula: H2CC(CH2COOH)HCONHC fR-j) (R2)C00R where R and R-j are CH3 or CgHg and R2 is ^4-7 alkyl having the stereo chemical form L-L, DL-L, L-DL, or DL-DL; 4797 (7) Those sweetening agents having the formula: H,N - CH - CONH-CH - COOR - 1 1 CH, 1 2 ch2 I I COOH 1 pH shown in British Patent 1,339,101; wherein R is a lower alkyl such as methyl and is prepared by reacting an N-protected-L-aspartic anhydride with L-phenylalanine lower alkyl esters, and (8) Those sweetening preparations having the formula L-aspartyl-L-1, 4-dimethyl-pentyl amide disclosed in German Patent No. 2,306,909, In the preferred spray drying process, the L-aspartic acid derivative _ crystal solids at a minor weight percent are admixed with water and converted into a slurry maintained at a temperature much below 150°F and typically at ambient room temperature conditions, whereby a minimum of the sweetening compound is allowed to go into solution, the vast majority of the derivative crystalline materials being undissolved and at most hydrated. This slurry is thereafter subjected to a hydromill processing wherein it will be force hydromilled or otherwise colloidally milled under pressure between a narrow orifice operative to sub-divide the crystalline material to a uniform, particle size distribution as by passage between a mill having an 2Q opening less than 125 microns intermediate the working mill faces.

The hydromilled slurry is thereafter spray dried into the intended form. The partial solution of the sweetening compound will be just sufficient to provide the agglutertating adhesion intermediate the undissolved crystalline sweetening, compound solids whereby when a droplet is caused to undergo evaporation the crystals will be randomly aggregated at their spaced points of contact through the intermediation of the re-dried compounds per se.

As indicated, the slurry may be dried by means other than spray drying, spray drying being most preferred in that by the formation of a droplet and the surface tension effects produced thereby the crystals are caused to be assembled into a spherical aggregated condition whence they may be permanently bonded to one another in the structure intended to provide a substantial immobilization and reduction of the effects of the electrostatic charges thereof. A slurry may be dried by any one of a number of well known drying methods of use in accordance with the foods arts such as drum drying, oven drying, freeze drying, etc.; in all of these applications, a slurry form that is relatively cool will be employed and if the slurry is dried in this unitary condition en masse, it will be subsequently subdivided into the granular state of use.

In lieu of a slurry form, a dough may be produced which takes advantage of the glutinous character of the peptide and equivalent hydrated crystals which is generated by the addition of a minor weight percent of water thereto, whence a suitable dough or meal that is moist will be produced and converted into a shape-retaining form as by the preferred step of extrusion subsequent to which the shape will be redried and incident to which redrying the individual crystals will be permanently bonded to one another through the intermediation of the redried dissolved sweetening compounds.

The slurry or dough practices do not preclude the presence in the aqueous phase of compatible inert or adjunctive agents such as colors and even flavors provided they are sufficiently incapable of entering into unstabilizing reactions with the L-aspartic acid derivative; thus, the aqueous medium used to produce the slurry or meal may have the coloring matter dissolved in the aqueous solvent; e.g. a spray dried form can be advantageously colored requiring no blending for this purpose. Likewise, water insoluble materials may be emulsified or homogenized in the aqueous medium forming a slurry or the dough for efficacious combination with the sweetening compound, the remaining water present being operative to effect the partial dissolution of the compound and form the agglutenating bridging solution.

Moreover, other artificial sweeteners such as saccharin and/or cyclamates may be blended at minor weight percents of the total composition to provide a balanced organoleptic sweetening impact by force of the uniformity of their distribution throughout the slurry or dough matrices depending upon the particular process employed; in this application, it will be desired to employ the cyclamate at a very minor weight percent of the saccharin which in turn will be a very minor weight percent of the total L-aspartic acid compound solids used whereby a preferred balanced organoleptic sweetness will be afforded when the total sweetening compounds are rendered solubld and used in beverage or other food applications. In these applications, the artificial sweeteners may be either dissolved in the aqueous phase or dry blended in the non-aqueous phase and will be effectively fixed through the random aggregation of the crystalline L-aspartic acid derivative compound per se.

All of these applications will produce a most flowable and blendable, stable, highly soluble composition which avoids the disadvantages stemming from the electrostatic properties still possessed by the compound jq - itself. .

The invention will now be more fully understood by reference to the following Example.

Example APM crystals (30%) and room temperature tap water (70%) are admixed; the admixture is-then charged to a Fryma mill wherein the particles are caused to pass an opening having a gap setting of about 75 microns operative to reduce the particle size of the APM crystals and subdivide any clusters thereof resulting in a fluid, pumpable, creamy slurry which at room temperature is pumped to a spray drying, atomizing nozzle which charges, under a spray pressure of 425 psig, the droplets into a vertical, spray drying tower having an inlet drying air temperature of 410°F and an outlet air temperature of about 235°F with an air flow of approximately 2600 cubic feet per minute. The dried droplets charge was recovered at a moisture content of 1.07% and a density of 0.248 grams per cc and 0.304 grams per cc packed - the density resulting from tapping a charge of the material until it approaches asymptotic density reduction under the influence of tapping per se with no overt positive mechanical displacement force.

The dried particles had the following particle si2e distribution: Sieve Number (U.S.S.) Ί θη Sieve +60 θ·60 -60,+70 25.4 -17,+120 58.03 -120,+140 Π-30 -140,+200 3.80 -200,+300 0.30 -300 0.07 The dried product will be noted to have a very uniform particle size distribution wherein 99% of the particles are between 60-200 mesh size; advantageously the composition has a narrow particle size distribution such that the particles are an amount of 1.10 grams of the spray dried APH agglomerates, dry blended with 3.60 grams of anhydrous citric acid can be spoon-stirred in 1892 milimeters of water at 45°F for 40 seconds and will form a complete solution; a like mixture of APM-acid mix that is unprocessed will take between 60 and 90 seconds to go into solution depending upon particle distribution and size of the sweetening compound therein.

A complete beverage mix of colour, flavour and citric acid, blended with the processed APM particles of this invention, had a free flow capacity which was quite acceptable to food manufacturing processes.

We are aware of the Food Regulations 1969 and in so far as the present invention relates to the use of artificial sweeteners which are governed by these regulations, we make no claim to the use of the invention in contravention of these regulations.

Claims (18)

1. A process for producing a flowable dry sweetening composition which comprises admixing crystalline particles of an L-aspartic acidderived sweetening compound with an amount of water sufficient either (a) to fonn a mixture of undissolved compound particles therewith and to cause a minor amount of the compound particles to be dissolved by the water to form an agglutenating solute, milling the compound particles admixed with water to a uniform, cluster-free slurry, causing the resulting solute solution to be distributed throughout the ranaining undissolved compound particles while causing the particles to arrange themselves randomly witft respect tn’.nne another, and drying the solution to immobilize the particles in the random arrangement thereof at spaced points pf contact through the intermediation of the redried compound, the sweetening composition consisting essentially of the particles immobilized by the redried compound, or (b) to form a semi-moist meal Or dough and to cause a minor amount of the compound particles to be dissolved by the water to form an agglutinating solute which enables the moist mixture of crystalline solids to be converted into a handleable mass, shaping and subsequently drying and grinding the mass to immobilize the particles in the random arrangement thereof at spaced points of contact through the intermediation of the redried compound, the sweetening composition consisting essentially of the particles immobilized by the redried compound.

2. A process as claimed in claim 1 wherein the compound particles are milled in step (a) to a particle size less than 125 microns.

3. A process as claimed in claim 1 or claim 2 wherein the amount of water in step (a) is a major percent by weight of the admixture of compound and water.

4. A process as claimed in any one of the preceding claims wherein the slurry in step (a) is maintained below 150°F prior to drying.

5. A process as claimed in claim 4 wherein the slurry in step (a) is maintained at ambient temperature prior to drying.

6. A process as claimed in any one of the preceding claims wherein the slurry in step (a) is hydromilled. 4479γ Ί. A process as claimed in claim 6 wherein the slurry in step (a) is spray dried.

7. 8. A process as claimed in claim 1 wherein in step (b), thecompound particles are distributed in an amount of water which forms a doughy, shaperetaining meal having the solution of sweetening compound distributed therethrough to agglutinate the particles in the random arrangement.

8. 9. A process as claimed in claim 8 wherein the meal is shaped and subdivided.

9. 10. A process as claimed in any one of the preceding claims wherein the compound is an alkyl ester of·L-aspartyl-L-phenylalanine. i

10. 11. A process as claimed in claim 1 substantially as hereinbefore ·! described with reference to the Example.

11. 12. A free-flowing water soluble powdery sweetening composition which comprises immobilized crystalline particles of an L-aspartic acid-derived sweetening compound aggregated to one another at spaced points of contact through intermediate aggregating bonds formed by redried quantities of the compound, the dissolved and redried form of the compound at the spaced contact points being a minor amount of the L-aspartic acid sweetening compound present, the sweetening composition consisting essentially of the L-aspartic acid sweetening compound particles immobilized by the redried compound.

12. 13. A composition as claimed in claim 12 wherein the compound is an alkyl ester of L-aspartyl-L-phenylalanine.

13. 14. A composition as claimed in claim 13 wherein the compound is L-aspartyl L-phenylalanine methyl ester.

14. 15. A composition as claimed in any one of claims 12 to 14 wherein the sweetening composition contains minor quantities by weight of the total composition of other artificial sweeterners.

15. 16. A composition as claimed in claim 12 substantially as hereinbefore described with reference to the Examples. n. 4 4 79 7'

16. 17. A flowable dry sweetening composition when prepared by a process as claimed in any one of claims 1 to 11.

17.

18. A comestible when sweetened using a sweetening composition as claimed in any one of claims 12 to T7.