US3385713A - Stabilization of flavoring, odorant and perfume compositions - Google Patents

Description

wwha z. 2 M! c. 3522 65:. v w w v Q m 1 A. A. LEVINSON ETAL STABILIZATION OF FLAVORING, ODORANT AND PERFUME COMPOSITIONS Flled May 26, 1966 'a w dsaa HQLDBLBO &

MM JMM aswodsaa aonarao a flmmwimckmza n May 28, 1968 United States Patent 3,385,713 STABILIZATION 0F FLAVORING, ODORANT AND PERFUME COMPOSITIONS Arthur A. Levinson, Chicago, Lawrence C. Radtke, Homewoorl, and Kenneth B. Basa, Evanstou, Ill., assignors to H. B. Taylor Co., Chicago, 11]., a corporation of Illinois Continuation-impart of application Ser. No. 399,279, Sept. 25, 1964. This application May 26, 1966, Ser. No. 559,660

7 Claims. (Cl. 99--140) ABSTRACT OF THE DISCLOSURE A stabilized liquid, flavoring, odorant and perfume composition comprising from Ms to 90% by weight in relation to solvent of a carbonyl containing compound, an aliphatic polyhydroxy, alcohol carrier and solvent containing at least two hydroxy groups which are substituted in the 1,2-; 1,3-; and 1,4-positions and an alkaline material present in an amount suflicient to substantially inhibit 'dioxolane formation and less than the amount required to promote alkali catalyzed side reactions.

This invention is a continuation-in-part of our Ser. No. 399,279, filed Sept. 25, 1964 now abandoned, and relates to the stabilization of flavoring, perfume and odorant compositions and more particularly to the stabilization of those compositions which contain aliphatic polyhydroxy alcohols, and flavoring, odorant and perfume components, and especially those containing a carbonyl functional group.

The formulation of flavoring, perfuming or odorant compositions used in the food, cosmetic, tobacco, aerosol spray, and similar industries, is well known. Usually these compositions, natural or synthetic, contain as essential flavor or odor factors, compounds having carbonyl groups, such as aldehyde or ketone groupings. These compositions are often formulated for commercial purposes as solutions which are used by the final user or manufacturer in small amounts. It has been the practice in the past to utilize various solvents which are relatively innocuous and nontoxic and which do not in themselves contribute altered flavors or odors to the final product. One group of such solvents or vehicles is known as polyhydroxy alcohols which may be exemplified by ethylene glycol, propylene glycol, glycerol, sorbitol, 1,3- butanediol, 1,4-butanediol, 2,5-hexanediol, and the like.

While those formulations which incorporate aliphatic polyhydroxy alcohols or compounds as carriers and solvents have been eminently satisfactory in many respects, it has been found that storage or shelf life of such materials is relatively short. Thus, for example, a basic flavorant manufacturer formulating a conventional flavoring composition would often receive complaints that the product, when finally incorporated into a food, cosmetic, or similar composition, had an altered flavor or odor. In some instances the shelf life of particular flavoring compositions was relatively short and the industry, ascribing this to volatilization or oxidation, would not maintain stocks of this material on hand, since the change in these flavors or odorants was appreciated as a time dependent factor.

It is well known that the principal components of many synthetic and natural flavorants contain carbonyl groups, such as aldehyde, or ketone groups, such as benzaldehyde or vanillin. It has been found that those flavoring compositions, which contain such carbonyl groups, when admixed with aliphatic polyhydroxy alcohols of the aforementioned classes, result in the formacar 3,385,713 Patented May 28, 1968 ice tion of reaction products which are termed cyclic acetals or dioxolanes. The resulting reaction products contribute to changed and/or off flavor or changed and/or off odor and are responsible for commercial rejection of flavor or odorant materials. The reactivity of the various aliphatic polyhydroxy alcohols with carbonyl compounds may be divided into three classes. The first class is polyhydroxy alcohols which contain hydroxy groups on at least two adjacent carbon atoms. Such polyhydroxy alcohols rapidly produce 5-membered ring cyclic acetals, as may be exemplified by the following equation. Class 1 polyhydroxy alcohol reactions:

CH0 0 o oHl-oH-om H O Benzaldehyde Propylene Dioxolane Glycol It has been found that since this reaction proceeds rapidly and with relative ease, the effects on flavors where the conditions and components are ideal are noticed most rapidly. Other cyclic acetals of 6- and 7-membered rings are also formed with the appropriate polyhydroxy alcohols, more slowly in the case of 7-membered rings, and the off flavor development is accordingly less noticeable but nevertheless present. Examples of the formation of these cyclic acetals are as follows:

Class 2 polyhydroxy alcohol reactions:

6-membered cyclic acetals CH2 Z62 \ZHCIT3 |1H0 ofi orn-om-OH-otn I #00113 H OH oom hi1 ()H Vanillln 1,3-butanediol Dioxolane Class 3 polyhydroxy alcohol reactions:

7-membered cyclic acetals Cl'lrCH C CH2 J. (l

([JHO ClI -CH -OH -CH;

Benzaldehyde 1,4-butanedio1 Dloxolaue Accordingly it is one of the objects of the present invention to provide improved stabilized flavoring and odorizing concentrates which have an extended shelf storage life.

In one broad form the present invention is a stabilized flavoring, perfuming and odorant composition comprising a carbonyl compound and aliphatic polyhydroxy alcohol and a stabilizing amount of an alkaline material.

Another form of the present invention comprises a method of stabilizing flavoring, perfume and odor producing compositions containing carbonyl compounds as a flavoring and odorizing factor and a polyhydroxy alcohol by the addition thereto of a stabilizing amount of an alkaline material.

As indicated in the foregoing, the principal component of these flavoring or odorant compositions contain carbonyl groups such as aldehyde and ketone groups. Exemplary of well known compounds of this class are vanillin, ethyl vanillin, benzaldehyde, cinnamaldehyde, anisaldehyde, veratraldehyde, heliotropin, 2,6-dimethyl- S-heptenal, alpha-amyl cinnamaldehyde, 3-benzyl-4-heptone, citronellal, cuminaldehyde, 2,4-dimethyl acetophenone, 2,6-dimethyl octanal, p-ethoxybenzaldehyde, alpha-hexylcinnamaldehyde, hydroxycitronellal, methoxybenzaldehyde, 3-methyl-2-phenylbutraldehyde, 3-phenylpropionaldehyde, salicylaldehyde, orthometaor paratolualdehyde, and the like. Some esters which contain a carbonyl group, such as methylphenylethylglycidate, are also reactive. The carbonyl materials are ordinarily, and for the purposes of this invention, present in the commercial formulations in widely varying amounts, from as little as one-eighth of one percent to as much as ninety percent by weight.

The flavoring and odorant components may include one or more of the aforesaid carbonyl compounds to produce the desired flavor. Other materials which are not aldehydic or ketonic in their function may also be and are often incorporated in these compositions to achieve the desired result, although their pressence is not of substantial importance in the present context.

For purposes of this invention the polyhydroxy alcohols or compounds are divided into three classes, specifically:

(1) Polyhydroxy aliphatic alcohols which contain hydroxy groups on adjacent carbon atoms.

(2) Polyhydroxy aliphatic alcohols which contain hydroxy groups on carbon atoms separated by an intervening carbon atom, as be exemplified by a 1,3-dihydroxy compound, and

(3) Polyhydroxy aliphatic alcohols which contain hydroxy groups on carbon atoms separated by two intervening carbon atoms, exemplified by a 1,4-dihydroxy compound.

The polyhydroxy compounds which are often used as solvents or components in the preparation of commercial flavors, odorants or perfume concentrates, include, as common examples, propylene glycol; glyerol; ethylene glycol; 1,3-butanediol; l,4 butanediol; 2,5-hexanediol; and tetrahydric, pentahydric and hexahydric alcohols, such as mannitol and sorbitol, and the like. They may be used alone or as mixtures. It is quite often the practice to add varying amounts of other solvents which are acceptable to the particular trade in which the flavoring, perfuming or odorant composition is to be used including for example monofunctional alcohols, such as ethyl, isopropyl or the like.

More specifically the aliphatic polyhydroxyalcohols of the present invention may be characterized as containing at least two hydroxy groups which are substituted on carbon atoms which are in the 1,2-; 1,3-; or 1,4-positions or their equivalent spacing interval in another numbering system, such as for example, 2,5-hexanediol.

These materials are, for the purposes of the present invention, liquid compositions in which the flavor or odor producing carbonyl compound and other components are soluble. In some instances the polyhydroxy compounds function as humectants rather than solvents.

Ordinarily the commercial compositions will be found to contain a small amount of water, usually less than about 1%, which occurs or appears as 'a contaminant and is not considered to be a functional or important element of these compositions, except that excessive w'ater, however, may be undesirable from the point of view of shipping costs, certain final uses, and sometimes contributes to lack of miscibility of the final composition.

" The alkaline materials 41. i. which are useful in the production of the compositions and in the process of the present invention are alkalies, such as sodium and potassium hydroxides, and carbonates, basic or alkaline salts, such as sodium bicarbonate, potassium bicarbonate, sodium monohydrogen phosphate 'and sodium acetate, and butfer compositions containing alkaline compounds or alkaline salts, such as acetic acid-sodium acetate buffer and aminecontaining compositions, such as alkaline salts of. ethylenediaminetetracetic acid (EDTA), ethanolamine and tiiethylamine. Other organic-buffer forming materials may be used as the stabilizingalkaline material in the present invention. For example, a vegetable protein hydrolyzate which might be acidic, or caramefcolo'r'which is normally 'acidic, is neutralized "with a buffer forming salt, such as sodium bicarbonate. The neutralized substance then serves as a color or flavor component as well as a stabilizer in the present invention, because it inhibits dioxolane formation. Certain zwitter ions such as glycine have also been found to be useful as alkaline stabilizers. It has been found that the stabilization is achieved in the presence of an alkaline material irrespective of pH which may boom the acid side in buffer systems, as will be hereinafter more fully described. It should be understood that the term alkaline materials as used in this context refers to hydrogen ion acceptors.

Generally the alkaline material is present in rather small amounts suflicient to produce a stabilizing result in a particular composition. Thus the alkaline material may be present in concentrations of as low as about 2.5 10- molar and achieve a stabilization. Preferably, however, the alkaline material is present in a concentration of about 5 10- molar or more for best results. It should be understood that stabilization is within the limits herein described generally directly related to the amount of alkaline material used. Thus in most instances increase of the concentration of alkaline material results in increased stability until a plateau is reached and/or the point where a deleterious side-reaction occurs, which latter is termed the maximum concentration.

The maximum amount of alkaline material is governed by the amount of alkali necessary to produce the Cannizzaro reaction. As is well known, certain carbonyl compounds, especially aromatic aldehydes in the presence of aqueous alkali, react in the manner described by Cannizzaro to produce essentially equal amounts of the corresponding alcohol and acid from the aldehyde material. Thus in the instance of benzaldehyde an excessive amount of alkali would result in the production of benzoic acid and benzyl alcohol, with changes in the odor or flavor which are undesirable. In those cases where the carbonyl compound contains an alpha-hydrogen, the result will be an aldol type of condensation which in the context of the present invention is considered the full equivalent of the C-annizzaro reaction from the standpoint of undesirable side reactions.

The following examples will illustrate the preparation of compositions embodying the present invention.

Flavoring composition concentrates were prepared to show the stabilizing effect of alkaline materials. The compositions are described in the following:

The gas-liquid chromatography apparatus employed in the following examples was the Wilkens Aerograph A--P2, in which the column was 5 feet by inch stainless steel. The stationary phase was a General Electric silicone, SF-96, at 20% on acid-washed firebrick, 60-80 mesh. Routinely, the column temperature was held at centigrade, and the thermal conductivity detector at 235 C. The carrier gas was helium at a fiow rate of 50 milliliters per minute. The usual sample size was 10 microliters.

In the following examples, unless otherwise expressed, the parts are by volume.

EXAMPLE 1 Flavoring compositions were prepared by admixing 5% benzaldehyde with 95% propylene glycol on a volume-volume (v./v.) basis. In the control the propylene glycol was as received" from the manufacturer. In the stabilized sample of Example 1 the propylene glycol had been previously prepared by adding to it a 1% of a 0.1 M solution of sodium bicarbonate. The final molarity in the flavoring composition was accordingly about 1X10" 1M. Observations were made on both the control and the stabilized sample by gas-liquid chromatography at time intervals of 5 minutes, 5 hours and 4 days to ascertain dioxolane formation.

FIGURE 1 of the attached drawing shows the superimposed gas-liquid chromatography record of the unstabilized control sample. The area under the peak in the curve identified by reference numeral 3 represents the dioxolane product formed in less than five minutes after formulation. Areas under peaks numbered 4 and 5 show the amount of dioxolane product formed after the admixture stands for periods of 5 hours and 4 days, respectively.

FIG. 2 shows the gas-liquid chromatography results obtained in the stabilized sample of Example 1 containing sodium bicarbonate. The peak identified as 3a and 4a represents the dioxolane formation after 5 minutes and 5 hours, indicating no discernible change. The peak identified as 5a represents the dioxolane formed after 4 days storage.

The operating conditions of the gas-liquid chromatography apparatus were as described above. The detector attenuation was 4x.

As may be seen in the foregoing example, the stabilized compositions of this invention substantially reduce the rate of dioxolane formation which contributes to changed flavors upon aging.

Examples 2 and 3, following, represent imitation vanilla flavors which are effectively stabilized by the use of propylene glycol. In Example 2, 1% of an aqueous solution of 0.5 M sodium bicarbonate was added to propylene glycol. The final molarity of the sodium bicarbonate with respect to the propylene glycol solution is about 5X10 M. In Example 3 the propylene glycol was prepared by the addition of propylene glycol to 1 cc. of 0.1 M NaHCO to make a final volume of 100 cc. In each case the control was plain propylene glycol. The results are summarized in the table following each example.

EXAMPLE 2 Percent, w./v. l

Ingredient Control (2) Example 2 Vanillin 13. 5 13. 5 Ethyl vanllli 4. 5 4. 5 Heliotropin 25 25 Benzaldehyde 2 1875 2 1875 Non-carbonyl comp onent 2. 0 2. 0 Propylene glycol 79 79 1 Weight/volume. 2 Volume/volume.

TABLE 2.-IMITATION VANILLA FLAVOR. VANILLIN LOSS AND THE GROWTH OF THE VANILLIN-PROPYLENE GLYCOL DIOXOLANE Storage period, days The following'table illustrates the results of prolonged storage in terms of vanillin loss. TABLE 3.LOSS 0F VANILLIN AND GROWTH OF ITS PRO- E FOLbIIESNE GLYCOLDIOXOLANE IN 6% VANILLIN SOLU- Storage period, days Stabilized sample (3):

Dioxolane peak area, mm. Trace 96 Percent vanillin loss 9. 0 35. 8 Unstabilized sample (3) control:

Dioxolane peak area, mm 30 140 Percent vanillin loss 23. 8 41. 8 56. 7

The following samples were prepared using sodium acetate-acetic acid buffer solutions as a stabilizer for propylene glycol to show that alkaline material, even when in acidic solutions, are effective and that the stabilization is not merely a function of pH.

EXAMPLES 4 AND 5 Two buifer solutions of sodium acetate-acetic acid were prepared according to AOAC standard methods:

To 1 cc. of each of the above solutions was added propylene glycol to make 100 cc. The buffer propylene glycol in turn was used as a solvent in the preparation of 5% solutions of benzaldehyde and 6% solutions of vanillin. The solutions containing propylene glycol and pH 4.5 buffer showed no change after two days, and there was a slight change in solutions containing the pH 3.5 bulfer. This difference can be attributed to the lower sodium acetate content of the pH 3.5 system, resulting in a molarity of about 1.3 X l0- It has also been found that the stability achieved is indirectly proportional to the temperature at which the product is stored. Thus, for example, storage at 53 F. showed considerably less conversion of the carbonyl compound to dioxolane than samples which were stored at 86 F. The following example will illustrate the various compositions and the results obtained at various concentrations when stored for the indicated periods of time and temperature.

EXAMPLES 6, 7 AND 8 Ex. 6 Ex. 7 Ex. 8

Vanillin, percent 12.5 w./v 12.5 w./v 12.5 w./v. Propylene glycol, percent 87.5 v./v--... 87.5 v./v 87.5 v./v. Alkaline material molarity 1X10- 6X10- 1X10.

TABLE 4 [Percent Vanillin Loss] Days 7 14 21 28 35 7 14 21 28 35 Control. 16 36. 5 39 39 44 42 47 47 47 47 Example 6. 0 SI SI SI 6 8 12 21 22 22. 5 Example 7..-. 0 O 0 0 SI SI SI 7 10 17 Example 8.-.. 0 0 0 0 SI SI SI 7 7 7 SI: Slight to immeasurable.

Compositions of 5% cinnamaldehyde in 1,3-butanediol with and without stabilizer were prepared and analyzed by gas chromatography, both initially and at various intervals during the test period. The stabilized composition contained 1% v./v. of 0.5 M NaHCO;, (0.033% by weight TABLE Storage time (days) Pei-cent g g ga xloo 0 88 EXAMPLE Compositions similar to Example 9 were prepared using, however, 1% of a 0.1 N solution of glycerine as stabilizer. The following results were obtained:

Compositions were prepared and tested as in Example 9 using 5% vanillin in place of cinnamaldehyde and a 50/50 mixture of 1,3-butanediol and 1,2-propanediol. The stabilizer was 1% of 0.01 M NaHCO showing inhibition at very low concentrations.

TABLE 7 a unstabilizcd Stora e time (days) porcent[ ]X 100 Complete inhibition was obtained using concentrations of alkaline material of 0.1 M or 0.5 M NaHCO;;.

EXAMPLE 12 This example shows the difference between dioxolane conversion of cinnamaldehyde (5%) in 1,4-butanediol compared with stabilized cinnamaldehyde (NaHCO TABLE 8 unstabilized Storage time (days) peIcentIi JXIOO EXAMPLE 13 This example of 5% cinnamaldehyde in 2,5-hexanediol illustrates the formation of 7 membered cyclic acetals of dioxolanes. The difiiculty in ring formation is indicated by the time required to show diflerences between stabilized and unstabilized products. Some benefit, however, is seen in the use of a stabilizer. Thestabilizer in this instance was 1% of a 0.5 M NaHCO solution.

TABLE 9 H I Y uust-abilized Storage time (day s) percent[ ]X 100 8 EXAMPLE 14 This example shows the results of long term storage and the comparative stability as well as absolute stability of 5% anisaldehyde solutions in 1,3-butanediol. The alkaline material used was 1% of a 0.1 M NaHCO;, solution.

TABLE 10 unstabilized Storage time (days) percent/[ X 100 Absolute concentration of anisaldehyde remaining in solution at end of storage period.

Percent Unstabilized 2.5 Stabilized 73 A number of other formulations were prepared to show the broad scope of the present invention. These were prepared by the addition of 1 ml. of 0.1 N sodium bicarbonate solution (0.1 M) to 99 ml. of propylene glycol (to make 100 ml.). This stabilized glycol was used to prepare solutions of various carbonyl containing compounds including anisaldehy-de, ethyl vanillin, heliotropin, veratraldehyde, 2,6-dimethyl-5-heptanal, melanol, ethylmethylphenyl glycidate, and methyl hexyl ketone. Other polyhydroxy alcohols were also used in place of propylene glycol, including ethylene glycol, glycerol and sorbital. In all instances the addition of alkaline material resulted in greatly improved storage stability of the products.

While some of the examples of this invention have been specific to certain carbonyl compounds, polyhydroxy alcohols or alkaline materials, it should be understood that others can be used with equally good results.

The compositions and process of the invention can be applied to various technologies with beneficial effect wherever flavor or odor are important. It should be understood that flavor is, as a practical matter, very closely associated with the olfactory sense, and cannot be and is not fully separated therefrom. Particular applications include food flavors, especially where incorporated into food products which are subsequently placed on the grocery store shelf, such as cookies, cooky fillings, pastries, and the like. Cosmetics, sprays of the aerosol type, including insecticides, deodorants including stick deodorants, polishes, tobacco products, industrial cleaners, and other items will also benefit from the present invention.

While several particular embodiments of this invention are shown above, it will be understood, of course, that the invention is not to be limited thereto, since many modifications may be made, and it is contemplated, therefore, by the appended claims, to cover any such modifications as fall within the true spirit and scope of this invention.

We claim:

1. A stabilize-d liquid flavoring, odorant or perfume composition comprising from A: to by weight, in relation to solvent, of a carbonyl containing compound, an aliphatic polyhydroxy alcohol carrier and solvent containing at least two hydroxy groups in the 1,2-; 1,3-; and 1,4-positions, and a stabilizing amount of an alkalnie material present in an amount suflicient to substantially inhibit dioxolane formation and less than the amount required to promote alkali catalyzed side reactions.

2. A composition according to claim 1 wherein the carbonyl compound is an aromatic aldehyde.

3. A composition according to claim 1 wherein the alkaline material is present in a concentration of at least 2.5 X 10' molar.

4. A composition according to claim 1 wherein the polyhydroxy alcohol is propylene glycol.

5. A composition according to claim 1 wherein the polyhydroxy alcohol is 1,3-butanediol.

6. A composition according to claim 1 wherein the polyhydroxy alcohol comprises a mixture of at least two polyhydroxy alcohols.

7. A method of stabilizing a liquid flavoring, odorant or perfume composition containing compounds having carbonyl functional groups in an amount of from A5 to 90% by weight, in relation to solvent, and an aliphatic polyhydroxy alcohol carrier and solvent containing at least two hydroxy groups in the 1,2.-; 1-3-; and 1-4-positions, said polyhydroxy alcohol and carbonyl compound being characterized by a tendency to react and form cyclic acetals and ketals containing from 5 to 7 members in the ring structure which comprises adding to said compositions a stabilizing amount of an alkalinematerial sufficient to inhibit the formation of the cyclic acetals and ketals and in an amount less than is required to promote the formation of alkali catalyzed side reactions of the carbonyl compound.

References Cited UNITED STATES PATENTS 3/1936 Grifiith et al 9914O OTHER REFERENCES Merory, Food Flavorings, Avi Publishing Co., Inc. 1960 pp. 164-165 and 187-188.

Bennett, Substitutes, Chemical Publishing Co., Inc., Brooklyn, NY. 1943 pp. 120-121.

15 A. LOUIS MONACELL, Primary Examiner.

H. H. KLARE, Assistant Examiner.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,385,713 May 28, 1968 Arthur A. Levinson et al.

It is certified that error appears in the above identified patent and that said Letters Patent are hereby corrected as shown below:

Column 3, line 38, after "as" insert may line 47, "glyerol" should read glycerol Column 7, line 19, "glycerine" should read glycine Column 8, line 33, "sorbital" should read sorbitol line 65, "alkalnie" should read alkaline Column 9, line 11, "1-3" and "l-4" should read 1,3 and 1,4

Signed and sealed this 18th day of November 1969.

(SEAL) Attest:

Edward M. Fletcher, Jr. WILLIAM E. SCHUYLER, JR.

Attesting Officer Commissioner of Patents

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