SWEETENER COMPOSITION STABLE AGAINST HEAT

Abstract: This invention encompasses a heat stabilized composi­ tion of aspartame, its salts or metal complexes and a partially hydrogenated vegetable oil melting at about 120°F or above. The composition is particularly useful in baking applications for aspartame.

Description: HEAT STABILIZED SWEETENER COMPOSITION Background of the Invention Aspartame (l-methyl N-L-a-aspartyl-L-phenylalanine) is a widely used sweetener. Its preparation and use are described in U. S. Patents 3,492,131 and 3,642,91. FDA regulations 21 CFR 172.804(c)(3) provide that when aspartame is used as a sugar substitute for table use, its label shall bear instructions "not to use in cooking or baking." This label warning was required by the FDA because aspartame was found to be unstable when heated. For example, aspartame would decompose in typical baking situations such as making cakes, cookies, breads.and the like. This invention solves the problem of aspartame's instability during baking. Brief Description of the Invention Aspartame, salts and metal complexes thereof are protected during the baking process by coating the sweetener with a partially hydrogenated vegetable oil. It is important that the aspartame, salts or metal complexes thereof and partially hydrogenated vegetable oil be formed into 8-40 standard mesh* particle size, so that aspartame *Standard mesh refers to standard screens which pass particles with diameters of 2308 microns for 8 mesh, 840 micron for 20 mesh, 20 micron for 40 mesh, 177 micron for 80 mesh. will be released in the later part of the baking cycle. Preferably an aspartarne sweetener is first granulated to 14 to 80 standard mesh sizes and most preferably to 14 to 30 standard mesh sizes and then are coated to form 8 to 40 standard mesh granules (with a partially hydrogenated vegetable oil). Thus the invention encompasses a heat stable sweetening composition comprising 8-40 mesh particles containing aspartame, salt or metal complexes thereof and 30-90% by weight of partially hydrogenated vegetable oil melting above 1200F. The invention utilizes the principle that solid aspartame is significantly more stable than aspartame in solution. Coating with compatible fat will prevent aspartame from dissolving, thus stabilized, during preparation and baking. Both the type of the fat and the particle size of fat coated aspartame have been found to be critical. The melting point of the fat is also an important factor for both stabilizing aspartame in baking. and making a granular product. This principle is also applicable to other artificial sweeteners such as saccharin and acesulfame K and con0binations with aspartame. DETAILED DESCRIPTION OF Tr.r INVENTION Aspartame (l-methyl N-L-o-aspartyl-L-phenylalanine) has the following chemical formula EMI4.1 Salts of aspartame are also effective sweeteners of generally greater stability than aspartame itself. Typical salts are: sulfate, and lower alkyl sulfonate wherein the lower alkyl group contains 1-4 carbon atoms. Preferred salts are: Bis (hydrogen aspartyl phenylalanine methyl ester) sulfate represented by the formula (APM.H)2SO4; hydrogen aspartyl phenylalanine methyl ester methyl sulfonate, represented by the formula (APM*H)S03CH3 Metal complexes of aspartame are likewise more stable in the solid state than aspartame alone. Typical metal complexes are derived from pharmacological lv acceptable metal ions and anions. Typical metal ions are Ca++, Zn++, Mg++, Al+++, Fe++ and Fe+++ and typical anions are chloride, acetate, sulfate, and phosphate. Preferred aspartyl phenylalanine methyl ester (APM) metal complexes are: ++ Mg APM-2C1 Fe APM-3C1 Al 2APM-3Cl Ca Ca ++ APM-2C1 Zn ' APM-2C1 It has been found that aspartame; its salts and metal complexes can be protected by fats during the baking cycle, particularly by partially hydrogenated vegetable oils melting above 1200F. Partially hydrogenated triglyceride vegetable oils such as soybean, palm, cottonseed oils melting above 1200F are preferred fats useful in practicing the invention. Typically about 3-9 parts by weight of fat are used to coat 7-1 parts by weight of APM, its salts or metal complexes. The APM, its salt or metal complex is coated with fat by either melting the fat and adding APM or by intermixing APM and fat prior to melting the fat. The fat is allowed to harden and the mass of fat coated particles is filtered through standard mesh screen to obtain fat coated APM particles in the size range of 8-40 standard mesh or about 2380 to 420 microns. An ideal coating is not only compatible with aspartame but also has a melting point about 1000C to release aspartame until the end of baking cycle. However, a mechanism other than melting fat is needed to slow down the release of aspartame during baking. This can be accomplished by increasing fat coating thickness and/or the particle size of the baking product to increase the diffusing time of the melted fat into the matrix of cake. Therefore, particle size is important because it provides controlled release of APM at the end of the baking cycle. If the particle size is too small, the APM will be released early in the baking cycle and will be thermally decomposed. If the particle size is too large, sweetness will not be thoroughly released and distributed. Therefore, the particle size, the type and the melting pint of the fat are critical. It has been found advantageous to include acidic polydextrose with the APM during the fat coating process when the product will be used to sweeten baked goods with high pH environment such as a chocolate cake. The polydextrose is in the amount of 3 to 8 parts of APM. The invention is further illustrated by the following examples which are intended to illustrate the invention and not limit it in spirit and scope. Example 1 Granule Preparation Method I 30 parts of partially hydrogenated triglyceride soy bean oil melting at 151-1580F is melted in a flat bottom pan. 10 parts of aspartame (APM) is gradually added so the powder is coated by the melted oil. Heating is discontinued and 60 parts of polydextrose powder is dispersed in the melted oil by stirring. The mass is stirred during solidification to produce small granules. The granules are separated on a standard 20 mesh screen. This method is applicable when using 10-30 parts of fat. Method II Polydextrose - aspartame non-porous granules(a) are made by adding a solution of 400 parts of polydextrose dissolved in 150 parts by volume of hot water to 600 parts of aspartame with stirring and drying by heating until substantially dry granules are formed. The granules are passed through a 30 standard mesh screen. Method III 3 parts of APM and 2 parts of polydextrose were mixed and granulated in a high-speed stirring granulator using water (6-10% by weight) granulation solvent and heat to facilitate granulation. The granules were tray dried and screened to la-30 mesh size distribution. The above granule was coated with 50% Duratex using a fluid-bed granulator which has a heating and pumping system to melt and spray high melting point fats. Part of the coated granules were screened to 12-30 mesh and 16-30 mesh samples. (a)The porous granules were prepared by mixing APM with granulating compounds, such as polydextrose or maltrin M100, and water or water-alcohol mixture to make a dough, which was expanded and dried in vacuum oven at 8O0C. The dried product was then milled to granular powder. These granules are coated with fat by mixing SO parts of the granules with 50 parts of fine powder fat and slowly heating with stirring until the granules are coated. The coated granules are passed through both 10 and 20 standard mesh screen. Both Methods I, II and III are applicable when no polydextrose is used. For example, aspartame may itself by granulated or mixed with other granulating agents. The heat stabilized compositions of the present invention may be utilized as in one or more of the following Examples. Example formulations 2 The formulations of cakes used in the following examples: Yellow Cake* Chocolate Cake Ingredient APM SUGAR APM SUGAR Sugar - 200 - 206 Aspartame 1.2 - 1.2 Maltrin MlOO 115 - 200 Flour 154 165 147 147 Cocoa Powder - - 56 56 Baking Powder 6.8 6.8 1.2 1.2 Baking Soda - - 3.1 3.3 Salt 3.4 3.5 3.6 3.6 Shortening 50 55.6 36 42 Water - - 92 92 Milk 194 180 - Buttermilk - - 99 99 Egg 54 70 54.5 54.5 Vanilla 3.1 4.2 1.8 1.8 *Polydextrose- APM yellow cake: The same as APM yellow cake except Maltrin.MlOO is replaced by the same amount of polydextrose. ExamDle 3 Compatibility between different types of fats and APM compounds. The following results were obtained by the analysis of fat coated samples. Unheated samples were used as controls to determine high-temperature compatibility. For all samples the weight ratio used was 9:1 (fat:APM compound). The samples were heated at 1100C for 0 minutes. APM was extracted from a fat coated sample using solvent-solvent (0.01 N HCl - methylene chloride) extraction and determined by an High Performance Liquid Chromatographic (EPIC) method. APM Content (%) % Degradation Composition Control Heated (wt ratio) Sample Sample Duratex(9),APM(1) 9.96 9.33 6.3 Durkeel7(9), APM(1) 10.40 8.40 18.7 KLX(9),APM(1) 10.20 8.50 16.7 Aratex(9),APM(1) 9.60 9.74 0 Kaomel(9),APM(1) 9.84 8.74 11.2 Duratex(9),(APM--H)2 SO4(1) 7.32 7.24 1.1 Atmos K150(9),APM(1) 9.2o 3.92 57.6 Myverol(9),APM(1) 9.50 0 100 Glycerol Monosterate(9), APM(1) 7.65 2.23 - 70.9 Stearic Acid(9),APM(l) 9.36 0 100 Stearic Acid(9), 8.37 2.60 68.9 (APM-H)2S04 This study demonstrates that triglyceride fats have the best compatibility with APM compounds at high temperature and are preferred for use in coatings. Example 4 Temperature profiles of cakes during baking. The temperature inside of a cake during baking was monitored and recorded every minute using a thermocouple inside the cake. Results show that at the end of 40 minutes baking period the cake temperature plateaus at 112-1200C. Therefore, the maximum temperature of a baking cake is significantly lower than the degradation temperatures of APM (1600C), (APM*H)2S04 (1800C), and APMCaCl2 (-1750C) in solid form. Therefore, if these sweeteners can be kept in solid form, e.g., by fat coating to prevent them from dissolving in water, they are stabilized during baking. Example 5 Summary of assay results by an HPLC method for yellow cup cakes. Coating Method Composition Particle APM Degrada- Relative Spl of Sweetener Size Recovered tion Recovery No. (wt ratio) (mesh) (%) DKP* AP- % of APM Remark 1. APM 38.3 30.5 8.7 49.4 Control 2. APM 31.1 34.1 8.5 42.2 Control 3. APM(1), Durkee 17(3), Polydextrose I/#20 62.2 25.0 3.4 68.7 (6) I/#20 62.2 25,0 3.4 68.7 4. APM(1), Dura tex(3), Polydextrose (6) I/#20 53.2 20.3 2.9 69.6 5. APM(1), KLX (3), Po lydextrose (6) I/ < 20 56.7 32.4 4.6 60.5 6. (APM'H)2 SO4(1), Durkee 17(3), Polydextrose (6) I/'20 50.1 14.5 3.2 73.9 7. APM.CaCl2(1), Durkee 17(2), Polydextrose (5) I/#20 50.1 15.2 3.3 73.0 8. (APM-H)2S04* (3), Durkee 17(8), Polydextrose (12) Maltrin M100(2) I/ < 20 45.2 14.4 2.8 72.4 *DKP is diketopiperazine degradation product'of APM. **AP aspartyl phenylalanine, a minor thermal degradation product of Coating Method Composition Particle APM Degrada- Relative Spl of Sweetener Size Recovered tion Recovery No. (wt ratio) (mesh) (%) DKP* AP* % of APM Remark 9. Granule A [(APM.H2SO4 (3), Poly dextrose(3), Maltrin 'M100(g) /L30 40.8 27.5 7.2 54 Control 10. Granule A(2), Duratex(3). II/ < l0 61.8 16.3 3.3 75.9 11. Granule B [APM(1), Polydextrose (2), Maltrin M100(2) (1), Duratex(1) II/#10 52.0 28.2 4.2 61.6 12. Granule C [ (APME)2S04 (1.1), Poly dextrose(l), Maltrin M100 (1)}(5), Duratex(3) II/ < 20 60.5 13.7 1.6 79.8 13. Granule C(1), Duratex(l) II/#20 61.9 15.2 - -80.3 14. Granule C(1), Duratex(l) II/ < 10 68.5 12.2 - -84.9 > 20 15; Granule C(2), Duratex(3! II/ > 20 60.3 23.5 2.71 69.7 < 10 16. Granule C(1), Duratex(l) Polydextrose Cake II/ > 20 80.1 11.7 87.2 The cake < 10 has a sour and bitter taste The above results indicate that: (1) The combination of fat coating and a micro-environment of polydextrose, which is acidic, has enhanced the stability of APM in baking by 20% or more. (2) Using compounds such as (APM.H)2S04 and APMiCaCl2, which have better thermal stability than APM, instead of APM has significantly reduced the degradation to DKP. (3) The higher melting fats, Durkee 17 and Duratex, are somewhat better than the lower melting one, KLX. (4) In the studies with Granule C the best results are obtained with a 50% Duratex coating and a uniform particle size between 20 and 10 mesh. ExamDle 6 Summary of assay HPLC results for APM in chocolate cupcakes. Coating Method % - Composition Particle APM Degrada- Relative Spl of Sweetener Size Recovery tion Recovery No. (wt ratio) (mesh) (%) DPK* % of APM Remark 1. APM 11.0 46.5 -19.1 Control 2. APM 17.1 63.6 -21.2 Control 3. Granule B [APM(1), Polydextrose (2), Maltrin M100(2)](1), Duratex(l) II/ < 10 26.0 45.1 -36.6 4. Granule A [(APM.H)2SO4 (3), Poly dextrose(3), Maltrin M100(4)] / < 30 13.1 53.1 -19.8 Control 5. Granule A(2) Duratex(3) II/ < lO 30.4 42.0 -42.0 6. APM.CaCl2(1) Durkee 17(2), Polydextrose (5) I/#1O 40.4 38.9 -50.9 7. Granule C (APM.H2 S04(1.1), Polydextrose(1) Maltrin M100 (1)](5) Duratex(3) II/ < 20 40.2 40.1 -50.1 8. Granule C(3) Duratex(l) II/ < 20 46.0 47.6 -49.1 Coating Method Composition Particle APM Degrada- Relative Spl of Sweetener Size Recovery tion Recovery No. (wt ratio) (mesh) (%) DPR* % cf APM Remark 9. Granule C(1), Duratex(1) II/ > 20 67.2 34.2 66.3 < 10 10. Granule C(2), Duratex(3) II/ > 2O 59.5 30.2 66.3 < 10 The results show that: 1. significantly increased APM surviving rates were found in all cakes using fat-coated APM sweetener. 2. the effects of both coating thickness and particle size on APM surviving rate in chocolate cake is even more profound than in yellow cake (Spl Nos. 8, 9, and 10). 3. the optimum results found for granule C samples are 50% fat-coating with a uniform particle size between 20 and 10 mesh, as used in yellow cake. Example 7 Sensory evaluation results. Cupcakes made with different APM samples and baked simultaneously were evluated for sweetness by 7 or more panelists. Coating Method Particle Study Composition Size Less Least Equal No. Cake of sweetener (mesh) Sweeter Sweet Sweet ¯Sweet 1Choc. (APM.H)2SO4 (1), Durkee 17(3), Poly dextrose(6)- Spl A. I/#20 1 7 - 2 (APM.H)2SO4' CaSO4(3), Durkee 17 (3), Poly dextrose(123, Maltrin M100 (2)-Spl B I/#20 7 1 - 2 2 Yell. SDl A I/ < 20 3 2 - 4 Spl B 1/ < 20 2 3 - 4 3- Yell. Spl A I/ < 20 10 1 Polydex- 1 10 trose-APM Comments: 5 noticed sourness in the cake with polydextrose. 4 Yell. Granule C II/ < 20 3 5 - 2 (APM.H2 SO4(1.1), Polydextrose( 1) Maltrin M100 (1)](5) Duratex(3) sugar 5 3 - 2 Coating Method Particle Study Composition Size Less Least Equal No. Cake of sweetener (mesh) Sweeter Sweet Sweet Sweet 5 Choc. Granule C(2), Duratex(3) II/ < 10 2 7 #20 Sugar 7 2 6 Choc. Granule C(1), Duratex(l) II/#10 6 1 #10O #20 Granule D II/ < 20 1 3 2 [APM(1), po lydextrose (2) Maltrin MlOO(2) ](1) Duratex(1) Granule D(1), II/#10 Duratex(1) > 20 2 4 The above results indicate 1. In baking, the stability of fat-coated (APM-H)2SO4.CaSO4 compares favorably to that of (APM-H)2SO. 2. A yellow cake made with (APMH)2SO4 coated with Durkee 17 is significantly sweeter than a polydextrose-APM yellow cake. 3. Cakes, both yellow and chocolate, made with fat-coated APM samples have sweetness and texture comparable to those of sugar cakes. 4. The chocolate cake made with coated (APMeH)2SO4 is sweeter than that made with coated APM. Example 8 Baking stability of Duratex coated non-porQus APM-polvsex-rose granulates. Coating Method Particle APM Study Composition Size Recovery Degradation % Relative No. Cake of Sweetener (mesh) (20) DKP APM Recovery . Yell. ***Granule E (APM(25), Polydextrose (15.6), Duratex (59.4)1 11/220 70.6 11.0 86. 510 Choc. ***Granule E II/#20 68.5 24.4 73.7 < 10 Yell. ***Granule F [APM (34.4), Polydextrose (15.6), Duratex (40.6)] II/#20 73.5 20.6 78.1 Choc. Granule F- II/ < 20 63.6 38.2 62.5 The above results clearly indicate that larger particle size and thicker coating improve APM baking stability and these factors are particularly important for chocolate cakes. ***APM-polydextrose granules passed through No. 30 mesh screen. This example demonstrates that APM dissolves significantly slower than its salts and complexes and this can be utilized as an important advantage for stabilizing APM in baking. The slow-dissolving factor can be enhanced by increasing particle size of APM. Therefore, Duratex coated APM granulates exhibit significantly better stability over Duratex coated APM powder. DoscriDtion o± Trademark Goods Maltrin M100 sold by Grain Processing Corporation is a spray dried hydrolyzed carbohydrate made from corn starch having a D.E. (Dextrose Equivalent) range of 9-12. Polydextrose sold by Pfizer Chemical Division is randomly bonded condensation polymer of dextrose containing minor amounts of bound sorbital and citric acid. Duratex sold by Durkee Industrial Foods is partially hydrogenated cottonseed triglyceride oil CMP of 141-147 F. Durkee 17 sold by Durkee Industrial Foods is partially hydrogenated triglyceride soybean oil CMP 152-1580F. KLX sold by Durkee Industrial Foods is partially hydrogenated vegetable oil (mixture of cottonseed.and soybean oil i;riglycerides) CMP 1240-13O0F. Aratex sold by Durkee Industrial Foods is partially hydrogenated vegetable oil which is a mixture of cottonseed, soybean, and palm oil triglycerides. Kaomel sold by Durkee Industrial Foods is partially hydrogenated vegetable oil, CMP 97-1010F. Atmos K150 sold by ICI is a mixture of mono- and diglyceride fats with a melting point ranye 135-1420F. Myverol sold by Eastman contains mainly (90%) monoglyceride fats with a melting point range 154-1630F. APM-calcium complex, 1:1 Grind CaCl2D2H20 crystal to fine powder. Thoroughly mix well 20.0 g APM and 10.0 g CaCl202F.2O. Add slowly with stirring 300 ml of 200 proof alcohol preheated to -60-700C. The solids should be almost completely dissolved. Eilter quickly by suction. Let the solution cool down to room temperature and then cool in refrigerator. Filter to collect precipitated product. Dry under vacuum and heat (-600C) overnight. - (APM . H)2SO4 . CaSO4 An amount of calcium bisulfate is dissolved or dispersed in small amount of distilled water. Alternatively, suitable amounts of calcium sulfate and sulfuric acid can be used to prepare the correspondlg bifulfate, in situ, in water. An amount of APM is then added and dissolved with gentle heating and stirring. The amounts used should meet the stoichiometry of APM:Ca++:E2SO4=2:1:1. An amount of organic solvent, such as alcohol and isopropanol, about 10 to 20 times the volume of water used, preheated to about 600C, is then added. The product will form suddenly as crystalline precipitate after 1 to 10 minutes of gentle heating and stirring. (APM * H)2S04 Sulfuric acid (96%, 1.66 g) was dissolved in distilled water (oil) and heated to about 400. To this solution was added aspartame (10.0 g) and the mixture was stirred. After the ester had dissolved to produce a clear solution, ethanol (00 ml), warmed to about 600, was added with stirring. The solution was quickly filtered and the filtrate cooled to about 50 to precipitate-the sulfate salt, filtered, washed with cold ethanol and dried in a vacuum at about 500 for about 2 hours to yield about 11 g of the above-titled salt. Examples of the sulfonate salts of the invention were prep2red using the foregoing procedure and substituting the appropriate organic sulfonic acid (RS032H) or sulfuric acid.

Claims: What is claimed is: 1. A sweetening composition comprising 8-40 standard mesh particles containing aspartame (APM), salts, or metal complexes thereof and 30-90% by weight of a partially hydrogenated vegetable oil melting about 1200F or above. 2. The composition according to Claim 1 containing aspartame (APM). 3. The composition according to Claim 1 containing aspartame (APMeH)2S04. 4. The composition according to Claim 1 containing aspartame (APMH)2S03CH3. 5. The composition according to Claim 1 containing aspartame (APM*H)2S04-CaS04, (APM'H)2S042 'CaSO41 (APM.H)2S04.MgSO4, or (APM'H)2S0402MgSO4. 6. The composition according to Claim 1 containing CA++(APM)2C1-. 7. The composition according to Claim 1 further containing polydextrose. 8. The composition of Claim 1 wherein the particles are 14-80 standard mesh size granules containing aspartame which are coated with partially hydrogenated vegetable oil melting about 1200F or above to form particles of 8-40 standard mesh. 9. The composition according to Claim 8 werein the particles are 14-30 standard mesh size granules containing aspartame which are coated with partially hydrogenated vegetable oil melting about 1200F cr above to form particles of 8-40 standard mesh. 10. The composition according to Claim 9 wherein the 14-30 standard mesh size granules are made of aspartame and polydextrose. 11. A method for stabilizing aspartame comprising coating aspartame containing granules of 14-80 standard mesh size with partially hydrogenated vegetable oil melting about 12O0F or above to provide particles of 8-40 standard mesh.

Inventors: TSAU, JOSEF HENG-KO, YOUNG, JAMES GEORGE
Applicants: THE NUTRASWEET COMPANY (A DELAWARE CORPORATION)
Application year: 1984
Main classification: A23L1
IPC codes: A23L1