WO1997011595A1

WO1997011595A1 - Method for treating mint plants and use of such mint plants

Info

Publication number: WO1997011595A1
Application number: PCT/US1995/012465
Authority: WO
Inventors: Sonya S. Johnson
Original assignee: Wm. Wrigley Jr. Company
Priority date: 1995-09-29
Filing date: 1995-09-29
Publication date: 1997-04-03
Also published as: AU3731195A

Abstract

Improved method of growing mint plants that provide mint oil having reduced sulfur levels, mint oil provided by such plants, and products made therefrom. The method includes reducing the amount of sulfur, if any, applied to the plants.

Description

S P E C I F I C A T I O N TITLE "METHOD FOR TREATING MINT PLANTS AND USE OF SUCH MINT PLANTS" BACKGROUND OF THE INVENTION

The present invention relates generally to mint flavors. More specifically, the present invention relates to methods of growing mint plants, from which mint flavors are derived as well as the use of same. It is known, in the food industry to use mint flavoring. For example, in the chewing gum industry, it is known to add mint flavor to chewing gum. An example of such a product is the use of spearmint oil in chewing gum. In addition to adding desirable taste characteristics to the chewing gum, such mint flavoring can add perceived breath freshening properties.

Mint flavors can be obtained from oil extracted from mint plants. For example, it is known to obtain peppermint and spearmint flavors from peppermint and spearmint plants, respectively.

One issue raised by mint flavor oils, such as peppermint and spearmint oil, is that they typically include sulfur-containing compounds such as dimethyl sulfide. Dimethyl sulfide causes poor quality peppermint oil in that it gives off a sul ury corn-like odor. In attempting to create a more palatable peppermint and spearmint oil, it is known to distill these oils to remove the dimethyl sulfide and other sulfur compounds.

Dimethyl sulfide is a very odorous chemical present at relatively low concentrations in field distilled oils, typically 200-800 ppm. An additional sulfide that is present is Mint Sulfide, which is a sulfur analog of Germacrene-D, a naturally occurring sesquiterpene found in mint oils. The level of Mint Sulfide in mint oils is generally low and tends to fluctuate from 0-2000 ppm. Mint Sulfide has an organoleptic character that is described as heavy, woody and earthy.

Generally, mint plants, such as peppermint and spearmint plants, are harvested by cutting the plant, leaving the plant lying in the field for several days to dry. After drying, the plant material is chopped and from the chopped plant material, one extracts/distills the oil. This extraction/distillation process is called a field distillation. After the field distillation, the crude mint oil is sent to a dealer/buyer to be further processed. In a number of uses, e.g., for chewing gum, additional secondary distillations are necessary in order to remove the dimethyl sulfide from the mint oil. Dimethyl sulfide is generally removed by distilling-off the low boiling portion of the oil. Other higher boiling chemicals, including Mint Sulfide, also affect the quality of the mint oils. Accordingly, the low and high boiling portions of the mint oil may be removed to reduce the sulfur-containing compounds, and other undesirable chemicals. This is generally referred to as "rectified oil."

These secondary distillations make the processing of mint oil time consuming and relatively expensive. There is therefore a need for an improved method for providing mint oils that do not necessarily require extensive secondary distillation processes.

SUMMARY OF THE INVENTION The present invention provides improved methods for providing mint oils having reduced sulfur levels reducing or eliminating the need for secondary distillation processes. Additionally, the present invention provides such mint oils and compositions using the same.

To this end, the present invention provides a method for growing plants containing mint oil wherein a reduced amount, if any sulfur is applied to the plants. In an embodiment no sulfur is applied to the plants.

In an embodiment, the plants contain peppermint oil. In an embodiment, the plants contain spearmint oil. In another embodiment, the present invention provides a method for providing mint oil comprising the steps of: planting a mint plant; allowing the mint plants to grow; harvesting the mint plants; extracting mint oil from the plants; and wherein sulfur is not applied to the mint plants.

In another embodiment, the present invention provides a method for producing food stuff including a mint flavor comprising the steps of adding to a food stuff mint oil extracted from a plant that has a reduced level, if any, of sulfur applied thereto.

In another embodiment, the present invention provides a chewing gum comprising: an insoluble portion; and a mint flavor extracted from a plant that had a reduced level, if any, of sulfur applied thereto. In another embodiment, the present invention provides a method for providing a mint oil comprising the steps of: a) subjecting a mint plant to reduced levels, if any, of sulfur applied to the mint plant to obtain the mint oil having low levels of sulfur compounds; and b) subjecting the mint oil to a single distillation process that removes at least a portion of the sulfur compounds, but not more than 3% of the mint oil. It is an advantage of the present invention to provide an improved method for growing plants containing mint oils.

A further advantage of the present invention is to provide improved mint oils.

Still further, an advantage of the present invention is to provide improved flavors for food products.

Another advantage of the present invention is to provide improved food products, including mint flavors. Furthermore, an advantage of the present invention is to provide confectionery products, including mint oils.

Further, an advantage of the present invention is to provide chewing gum, including mint oils. Still, an advantage of the present invention is to provide mint plants having a reduced level of sulfur.

Moreover, an advantage of the present invention is that it reduces the heat stress to the mint oils, improving yields of rectified oils and improving the flavor quality of the oil.

Additional features and advantages of the present invention are described in, and will be apparent from, the detailed description of the presently preferred embodiments and from the drawings. DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present invention provides improved mint oils and products using same. In this regard, it has been surprisingly found that by modifying techniques for growing mint, that mint oils having reduced sulfur content can be achieved.

For many years, in growing peppermint and spearmint plants, sulfur has been applied to the fields containing such plants. It has been surprisingly found, that this sulfur is retained in the plant and forms sulfur compounds found in the mint oil that is extracted from the plant. It has further been surprisingly found that by reducing, and even eliminating, the application of sulfur to the plants, that this does not adversely impact the oil yield. However, it does result in mint or mint oil harvested from the plants that has reduced levels of sulfur.

As previously noted, sulfur containing chemicals have been detected in field distilled peppermint and spearmint oils. The two identified chemicals are dimethyl sulfide and Mint Sulfide. Mint Sulfide can be easily synthesized by mixing a Germacrene-D enhanced peppermint oil fraction with elemental sulfur and irradiating at room temperature.

Accordingly, pursuant to the present invention, mint plants are grown in an environment wherein reduced levels, if any, of sulfur are applied to the plants. The mint oil extracted from the plants, grown pursuant to the present invention, will thereby have reduced sulfur levels as compared to plants grown with sulfur.

Pursuant to the present invention, the resultant mint oil from the plants can be used in a variety of different products. In this regard, the oil can be used in any food products where it is desirable to have a mint flavor, e.g., spearmint or peppermint oil. For example, in an embodiment, the mint oils of the present invention can be utilized to manufacture food stuffs, such as confectionery products. In a more specific embodiment, the mint oils can be used to create chewing gum, e.g., chewing gum including spearmint or peppermint flavor.

In this regard, the present invention also provides a mint flavor chewing gum comprising: a water-insoluble base portion; a water-soluble base portion; and a mint flavor agent derived from a plant that is grown pursuant to the present invention. The chewing gum may be of any of a variety of different chewing gums, including low or high moisture, sugar or sugarless, wax containing or wax free, low calorie and/or a chewing gum that includes dental health agents.

Chewing gum generally consists of a water-insoluble gum base, water-soluble portion, and flavors. The water- soluble portion dissipates with a portion of the favor over a period of time during chewing. The gum base portion is retained in the mouth throughout the chew.

The insoluble gum base generally comprises elastomers, resins, fats and oils, softeners, and inorganic fillers. The gum base may or may not include wax. The insoluble gum base can constitute approximately 5 to about 95 percent, by weight, of the chewing gum, more commonly, the gum base comprises 10 to about 50 percent of the gum, and in some preferred embodiments, 20 to about 35 percent, by weight, of the chewing gum.

In an embodiment, the chewing gum base of the present invention contains about 20 to about 60 weight percent synthetic elastomer, 0 to about 30 weight percent natural elastomer, about 5 to about 55 weight percent elastomer plasticizer, about 4 to about 35 weight percent filler, about 5 to about 35 weight percent softener, and optional minor amounts (about one percent or less) of miscellaneous ingredients such as colorants, antioxidants, etc. Synthetic elastomers may include, but are not limited to, polyisobutylene with a GPC weight average molecular weight of about 10,000 to about 95,000, isobutylene-isoprene copolymer (butyl elastomer) , styrene-butadiene copolymers having styrene-butadiene ratios of about 1:3 to about 3:1, polyvinyl acetate having a GPC weight average molecular weight of about 2,000 to about 90,000, polyisoprene, polyethylene, vinyl acetate-vinyl laurate copolymer having vinyl laurate content of about 5 to about 50 percent by weight of the copolymer, and combinations thereof.

Preferred ranges are, for polyisobutylene, 50,000 to 80,000 GPC weight average molecular weight, for styrene-butadiene, 1: I to 1: 3 bound styrene-butadiene, for polyvinyl acetate, 10,000 to 65,000 GPC weight average molecular weight with the higher molecular weight polyvinyl acetates typically used in bubble gum base, and 5 for vinyl acetate-vinyl laurate, vinyl laurate content of 10-45 percent.

Natural elastomers may include natural rubber such as smoked or liquid latex and guayule as well as natural gums such as jelutong, lechi caspi, perillo, sorva, massaranduba balata, massaranduba chocolate, nispero, rosindinha, chicle, gutta hang kang, and combinations thereof. The preferred synthetic elastomer and natural elastomer concentrations vary depending on whether the chewing gum in which the base is used is adhesive or conventional, bubble gum or regular gum, as discussed below. Preferred natural elastomers include jelutong, chicle, sorva and massaranduba balata.

Elastomer plasticizers may include, but are not limited to, natural rosin esters such as glycerol esters 20 of partially hydrogenated rosin, glycerol esters polymerized rosin, glycerol esters of partially dimerized rosin, glycerol esters of rosin, pentaerythritol esters of partially hydrogenated rosin, methyl and partially hydrogenated methyl esters of rosin, pentaerythritol esters of rosin; synthetics such as terpene resins derived from alpha-pinene, beta-pinene, and/or d- limonene; and any suitable combinations of the foregoing, the preferred elastomer plasticizers will also vary depending on the specific application, and on the type of elastomer which is used.

Fillers/texturizers may include magnesium and calcium carbonate, ground limestone, silicate types such as magnesium and aluminum silicate, clay, alumina, talc, titanium oxide, mono-, di- and tri-calcium phosphate, cellulose polymers, such as wood, and combinations thereof.

Softeners/emulsifiers hydrogenated may include tallow, hydrogenated and tallow, partially hydrogenated vegetable oils, cocoa butter, glycerol monostearate, glycerol triacetate, lecithin, mono-, di-, and triglycerides, acetylated monoglycerides, fatty acids (e.g. , stearic, palmitic, oleic and linoleic acids) , and combinations thereof. Colorants and whiteners may include FD&C-type dyes and lakes, fruit and vegetable extracts, titanium dioxide, and combinations thereof.

The base may or may not include wax. An example of a wax-free gum base is disclosed in U.S. Patent No. 5,286,500, the disclosure of which is incorporated herein by reference.

In addition to a water insoluble gum base portion, typical chewing gum composition includes a water soluble bulk portion and one or more flavoring agents. The water soluble portion can include bulk sweeteners, high intensity sweeteners, flavoring agents, softeners, emulsifiers, colors, acidulants, fillers, antioxidants, and other components that provide desired attributes. Softeners are added to the chewing gum in order to optimize the chewability and mouth feel of the gum. The softeners, which are also known as plasticizers and plasticizing agents, generally constitute between approximately 0.5 to about 15% by weight of the chewing gum. The softeners may include glycerin, lecithin, and combinations thereof. Aqueous sweetener solutions such as those containing sorbitol, hydrogenated starch hydrolysates, corn syrup and combinations thereof, may also be used as softeners and binding agents in chewing gum.

Bulk sweeteners include both sugar and sugarless components. Bulk sweeteners typically constitute 5 to about 95% by weight of the chewing gum, more typically, 20 to 80% by weight, and more commonly, 30 to 60% by weight of the gum.

Sugar sweeteners generally include saccharide containing components commonly known in the chewing gum art, including, but not limited to, sucrose, dextrose, maltose, dextrin, dried invert sugar, fructose, levulose, galactose, corn syrup solids, and the like, alone or in combination.

Sugarless sweeteners include, but are not limited to, sugar alcohols such as sorbitol, mannitol, xylitol, hydrogenated starch hydrolysates, maltitol, and the like, alone or in combination.

High intensity artificial sweeteners can also be used, alone or in combination with the above. Preferred sweeteners include, but are not limited to sucralose, aspartame, salts of acesulfame, alitame, saccharin and its salts, cyclamic acid and its salts, glycyrrhizin, dihydrochalcones, thaumatin, monellin, and the like, alone or in combination. In order to provide longer lasting sweetness and flavor perception, it may be desirable to encapsulate or otherwise control the release of at least a portion of the artificial sweetener. Such techniques as wet granulation, wax granulation, spray drying, spray chilling, fluid bed coating, coacervation, and fiber extension may be used to achieve the desired release characteristics.

Usage level of the artificial sweetener will vary greatly and will depend on such factors as potency of the sweetener, rate of release, desired sweetness of the product, level and type of flavor used and cost considerations. Thus, the active level of artificial sweetener may vary from 0.02 to about 8%. When carriers used for encapsulation are included, the usage level of the encapsulated sweetener will be proportionately higher.

Combinations of sugar and/or sugarless sweeteners may be used in chewing gum. additionally, the softener may also provide additional sweetness such as with aqueous sugar or alditol solutions.

If a low calorie gum is desired, a low caloric bulking agent can be used. Examples of low caloric bulking agents include: polydextrose; Raftilose, Raftilin; Fructooligosaccharides (NutraFlora) Palatinose oligosaccharide; Guar Gum Hydrolysate (Sun Fiber) ; or indigestible dextrin (Fibersol) . However, other low calorie bulking agents can be used.

A variety of flavoring agents can be used in combination with the refined mint flavor of the present invention. The flavor, which may only include the refined mint flavor, can be used in amounts of approximately 0.1 to about 15 weight percent of the gum, and preferably, 0.3 to 5%. Flavoring agents may include essential oils, synthetic flavors or mixtures thereof including, but not limited to, oils derived from plants and fruits. In addition to spearmint oil, mint oils include peppermint oil, as well as other mint oils. Artificial flavoring agents and components may also be used. Natural and artificial flavoring agents may be combined in any sensorially acceptable fashion.

By way of example and not limitation, examples of the present invention will now be given. EXAMPLES

A 39 acre plot area was divided into a 3 x 13 acre section in the peppermint growing area in Oregon. This 39 acre plot was a three-year-old existing mint field and was separated in February into plots A, B, and C. Plot A had a high level of sulfur application, Plot B had a lower level of sulfur application, and Plot C had no sulfur application.

On May 30, there was a first cut of all three fields since there was extensive growth of the mint of all three fields. After cutting, the hay was allowed to dry in the field and distilled on June 3-4. A portion of the oil recovered from the 1-2 acre strip at the center of each 13 acre parcel was set aside for testing.

First cut yields for all three plots were typical for a first cutting, and no significant differences were noted between the plots in either plant growth level or oil yield.

On August 27, the 39 acre field underwent the second cutting. The hay was allowed to dry in the field and distilled August 31. Again, a portion of the oil recovered from the 1-2 acre strip at the center of each plot was set aside for testing. Each plot yielded average yields, with no significant differences between plots.

The only disease/pest problem occurred in July, when the entire field was treated with the sulfur-containing pesticide Comite to control a mite problem that was more than likely brought on by the hot, dry weather. The soil and the irrigation water were tested in July for their sulfur (sulfate) contents with the water sulfur level being 4.3 ppm and the soil sulfur levels ranging between 19 ppm for Plot A, 18 ppm for Plot B and 13 ppm for Plot C. The total sulfur applications per acre and soil sulfur levels for the three plots were:

Plot A = 96 lbs. applied from March to July, with the soil sulfur levels ranging from 9 ppm in March before the first sulfur application, to 19 ppm in July after the final sulfur application.

Plot B = 81 lbs. applied from March to July, with the soil sulfur levels ranging from 14 ppm in March before the first sulfur application to 18 ppm in July after the final sulfur application. Plot C = 0 lbs. applied with soil sulfur levels ranging from 15 ppm in March, to 13 ppm in July.

Samples of the first cut oil and the second cut oil were analyzed by GC/FID and results are given in the following table. Relevant results are shown; the remaining composition of peppermint oil were basically the same for all three plots and typical of first and second cut field distilled peppermint oil. A = High Sulfur B = Medium Sulfur C = No Sulfur lst Cut 2nd Cut lst Cut 2nd Cut lst Cut 2nd Cut

Dimethyl Sulfide 0.061 0.039 0.042 0.023 0.048 0.014

Mint Sulfide 0.643 0.072 0.608 0.528 0.141 trace

Germacrene D 0.030 0.881 0.108 0.128 0.636 1.001

/9-Caryophyllene 1.536 2.088 1.683 1.992 1.731 2.280

S-Cadinene 0.075 0.116 0.087 0.082 0.155 0.125 α-Terpinene 0.488 0.425 0.518 0.403 0.560 0.369 -Terpinene 0.774 0.637 0.794 0.619 0.846 0.552

P-Cymene 0.181 0.076 0.137 0.099 0.098 0.071

Sabinene Hydrate 0.354 0.662 0.319 0.766 0.201 0.934

Trans-Ocimene 0.303 0.110 0.248 0.223 0.125 0.086

Cis-Ocimene 0.160 0.339 0.215 0.232 0.401 0.329

Pulegone 0.077 0.733 0.065 0.877 0.065 1.069

Menthofuran trace 1.080 trace 1.306 trace 1.843

Menthone 36.734 23.919 33.752 23.445 33.206 21.548

Menthol 33.737 42.459 35.969 43.485 34.690 43.734

There were differences in the oil profiles which were not attributable to the time of harvest, but seem to be due to different levels of sulfur application. These differences are listed below.

1. The dimethyl sulfide level in the second cut oil from Plot A (0.039%) was higher than the dimethyl sulfide levels in the second cut oils from Plot B (0.023%) or Plot C (0.014%). The dimethyl sulfide levels in all the second cut oils were 1/2 to 1/4 the levels present in the corresponding first cut oils. All indications are that the sulfur is being taken up by the plant and is being expressed as higher levels of both dimethyl sulfide and mint sulfide in the distilled oil.

2. The Mint Sulfide level in the second cut oil from Plot B (0.528%) and Plot A (0.072%) were higher than the trace mint sulfide level found in the oil from Plot C. There is an inverse correlation between the mint sulfide level and the sesquiterpene levels in the oils, in particular the Germacrene-D content. The second cut oil recovered from Plot B which contained the highest mint sulfide content, contained the lowest levels of Germacrene-D, /3-Caryophyllene and 6-Cadinene. The second cut oil recovered from Plot A was lower in its mint sulfide content and also contained higher levels of the sesquiterpenes. The oil recovered from Plot C only contained a trace of mint sulfide and the highest levels of the sesquiterpenes. In the first-cut oils a great difference was seen in the levels of - and 7-terpinene and p-cymene between the different plots, with the high sulfur plots having the lowest levels of the terpinenes and the highest levels of p-cymene, and as such, appeared to be oxidized. The sabinene hydrate, which can be converted to the terpinenes under acidic distillation conditions, was slightly higher in the high sulfur first-cut oils. The levels of both p-cymene and the terpinenes were highest in the high sulfur second-cut oils, and the levels of the sabinene hydrate were much lower in those same oils. This indicates that again in the high sulfur oils there was some oxidation of the terpinenes to p-cymene with a concurrent conversion of sabinene hydrate to terpinenes. All six of these oils were odor screened by five individuals. All five subjects thought that the oils recovered from the two cuttings of Plot C were of good quality, typical field distilled oils. They also thought that the oil recovered from the two cuttings of Plot B and the first cutting of Plot A were atypical, bad, sulfury, smelled like natural gas, etc. The oil from the second cutting of Plot A was considered atypical to marginal. It should be noted that the three oils with the most pronounced off-notes contained the highest levels of Mint Sulfide.

There is a direct correlation between the amount of sulfur used on the fields and the levels of sulfur- containing chemicals found in the oils as well as the other chemical differences noted above. There also appears to be negative sensory correlation between the applied sulfur and the organoleptic quality of the oil.

It is speculative that continued testing of these fields, specifically Plot C with no sulfur added, will continue to give oils with lower and lower amounts of dimethyl sulfide. There is the possibility that at some point levels of dimethyl sulfide and mint sulfide may be low enough to not require further distillation after field distillation to obtain a quality peppermint oil. With this reduction of dimethyl sulfide in the peppermint oil, further distillation to remove dimethyl sulfide with only a light distillation as described on U.S. Patent No. 5,425,962 or even less may be sufficient to obtain high quality peppermint oil for use in chewing gum. This patent discloses a method for light distillation that removes sulfur compounds, but not more than 3% of the composition.

It should be understood that various changes and modifications to the presently preferred embodiments described herein will be apparent to those skilled in the art. Such changes and modifications can be made without departing from the spirit and scope of the present invention and without diminishing its attendant advantages. It is therefore intended that such changes and modifications be covered by the appended claims.

Claims

WE CLAIM:

I. A method for growing mint plants comprising the steps of growing the plants without applying sulfur to the plants.

2. The method of Claim 1 wherein the plants contain peppermint oil.

3. The method of Claim 1 wherein the plants contain spearmint oil.

4. A method for providing mint oil comprising the steps of: planting a mint plant; allowing the mint plants to grow; harvesting the mint plants; extracting mint oil from the plants; and applying a reduced level of sulfur to the mint plants than is typically applied to mint plants.

5. The method of Claim 4 wherein the plants contain peppermint oil.

6. The method of Claim 4 wherein the plants contain spearmint oil.

7. The method of Claim 4 wherein no sulfur is applied to the mint plants.

8. A method for producing food stuff including a mint flavor comprising the steps of adding to a food stuff mint oil extracted from a plant that had reduced levels of sulfur applied thereto.

9. The method of Claim 8 wherein the food stuff is a confection.

10. The method of Claim 8 wherein the food stuff is chewing gum.

II. The product of the method of Claim 8.

12. The method of Claim 8 wherein the mint flavor is spearmint.

13. The method of Claim 8 wherein the mint flavor is peppermint.

14. The method of Claim 8 wherein no sulfur is applied to the plant. .

15. A chewing gum comprising: an insoluble gum base portion; a water soluble portion; and a mint flavor extracted from a plant that did not have sulfur applied thereto.

16. The chewing gum of Claim 15 wherein the mint flavor is spearmint.

17. The chewing gum of Claim 15 wherein the mint flavor is peppermint.

18 The product of the method of Claim 15.

19 A method for reducing the level of sulfur in mint oil extracted from a plant comprising the steps of reducing the level of sulfur applied to the plant when it is growing.

20. The method of Claim 19 when no sulfur is applied to the plant.

21. A method for providing mint oil comprising the steps of: subjecting a mint plant to reduced levels of sulfur; extracting mint oil from the mint plant; and subjecting the mint oil to a single distillation process that removes at least a portion of any sulfur in the mint oil but removes not more than 3% of the mint oil.