This disclosure relates to cooling compounds and to means of enhancing their solubility. Cooling compounds are compounds that give a cooling sensation to the skin and/or the mucous membranes of the nose and mouth. The compound N-(4-cyanomethylphenyl) p- menthanecarboxamide, disclosed in EP 1685093, and hereinafter referred to in this description for convenience as the Coolant, is one of the most potent cooling compounds yet discovered, particularly in its (7R,2 _l S ^, ,5R)-isomeric form - it has been shown to be up to an order of magnitude better than any other commercially- available cooling compound. It has received US FDA approval for use in consumables, and as a result, it is greatly in demand.

One problem hindering its possibilities is its poor solubility in all consumable solvents. This results in lower quantities being usable, and therefore a cooling effect considerably reduced over what could be possible. A number of solutions have been tried, and while these have improved the situation, they have not completely removed the handicap.

It has now been found that it is possible to use Coolant in higher proportions that hitherto achieved, allowing the full potential of the Coolant finally to be realised. There is therefore provided a cooling composition, comprising the Coolant in a cyclodextrin inclusion complex.

Cyclodextrins are cyclic oligosaccharides consisting of 6, 7, or 8 glucopyranose units with hydrophobic interiors, usually referred to as α-, β-, or γ-cyclodextrins, respectively.

Because of their water solubility and pharmaceutical acceptability, they have been widely used by pharmaceutical companies for the controlled-release delivery of pharmaceuticals. In addition, it was disclosed in WO 93/00018 that a particular cooling compound, 3,1- menthoxypropane-l,2-diol, could be combined with cyclodextrin to overcome problems with the softening of chewing gum bases containing high levels of 3,1-menthoxypropane- 1,2-diol. However, there is no indication in the art that cyclodextrin complexes would be effective in allowing the release of the Coolant into the mouth in an effective manner. The Coolant may be incorporated into the selected cyclodextrin by first dissolving the cyclodextrin in water and then stirring in the Coolant. All three cyclodextrins can solubilise the Coolant, but to a different extent, β-cyclodextrin has the highest affinity to the Coolant, i.e. it can solubilise more Coolant per mol of cyclodextrin, but because of the comparatively low solubility of β-cyclodextrin in water, the overall amount of Coolant solubilised by cc- and γ-cyclodextrins is higher.

In the case of γ-cyclodextrin, when γ-cyclodextrin is added to a saturated solution of Coolant in water, a soluble γ-cyclodextrin-Coolant complex is formed up to a γ- cyclodextrin concentration of 50 mM . If the concentration of γ-cyclodextrin in the system is further increased, the complex precipitates, and the Coolant concentration in the supernatant phase decreases. This permits an easy way of isolating complexes in solid form. The solubilities of cyclodextrins are considerably higher at elevated temperatures, hence more γ-cyclodextrin can be dissolved at e.g. 70°C. When, in the presence of Coolant, the solution is cooled down to 35-50°C, the complex precipitates first and can be removed by filtration before the pure cyclodextrin precipitates at even lower temperatures.

The resulting complex has the capacity to allow the incorporation into aqueous media of considerably more Coolant than is possible in water or any other food-grade solvent. As a result, a pronounced cooling effect is achieved.

The compositions may be used in any consumable composition in which cooling properties are desired. By "consumable composition" is meant any composition intended to be taken by mouth, either for ingestion or only into the oral cavity. The former includes all types of foodstuffs, baked goods, beverages, confectionery and the like, and the latter oral care products, such as toothpastes and toothgels, mouthwashes and medicinal products. The disclosure also provides a consumable composition, comprising a consumable product base and a cooling effect quantity of a cooling composition as hereinabove defined. It further provides a method of preparing a consumable composition having a perceptible cooling sensation, comprising the addition to a consumable product base of a cooling effect quantity of a cooling composition as hereinabove defined. By "consumable product base" is meant the totality of all the usual ingredients of such compositions in art-recognised quantities. By "cooling effect quantity" is meant the quantity sufficient to deliver the desired degree of cooling. No fixed proportions can be allocated to such uses, as the degree of cooling required will depend on how much cooling is desired in a particular application, which will in turn depend either on how much is normal for that type of composition or the effect that the individual flavourist wishes to achieve.

However, the use of a cyclodextrin complex of the type hereinabove described allows the use of a much higher proportion of the Coolant than has previously been possible. Instead of the lppm possible in water solution, the complex allows the use of proportions of several hundred more. For example, using such a complex, 200ppm is easily attainable in a chewing gum application. This is by no means an upper limit, as even higher proportions may be used, only practical considerations such as degree of cooling desired (or tolerable), and cost placing any limits on the proportion. The use of the complex hereinabove described makes possible hitherto unachievable cooling effects.

The disclosure is further described by means of the following non-limiting examples, which describe particular embodiments.

Example 1 - Preparation of Coolant - γ-cyclodextrin complex (vacuum drying)

163 g γ-cyclodextrin* (containing about 8.5% moisture) was dissolved in 250 g of water at 70°C. 2 g Coolant was added and the mixture was stirred for 6 hours at 70°C. The mixture was allowed to cool down to 40°C. The obtained precipitate was filtered and dried at 70- 80°C in a vacuum oven (10.6 kPa) until the weight did not further change.

* Cavamax W8 Food, Wacker Chemie AG Example 2 - Preparation of a Coolant - γ -cyclodextrin complex (spray drying)

350 grams of γ -cyclodextrin* was dissolved in 700 ml water at 70°C to make a one liter γ - cyclodextrin solution. 1 g Coolant was added to the solution. The mixture was stirred for 2 hours and spray-dried on a Niro Minor spray drier.

* Cavamax ^® W8 Food, Wacker Chemie AG

Example 3 - Sensory evaluation of Coolant inclusion complexes in solution

Panelists were asked to taste a saturated solution of Coolant in water (containing about 1 ppm Coolant) and a Coolant - cyclodextrin inclusion complex as described in Table 1. The panelists did not perceive the water solution as having a cooling sensation, whereas all panelists did perceive solutions of cyclodextrins containing Coolant at saturation levels as having a cooling effect.

Table 1

Cavamax W6 Food, Wacker Chemie AG

# ^# Cavamax ^® W7 Food, Wacker Chemie AG

# ^## Cavamax ^® W8 Food, Wacker Chemie AG

Example 4 - Preparation of chewing gum containing Coolant

Two batches of chewing gums were made according to the formula in Table 2: Table 2

⁺ Cafosa

+ ⁺ Givaudan

Pure Coolant (in Example C4) or the Coolant-y-cyclodextrin complex from Example 1 (in Example 4) were first suspended/dissolved in the flavor in each batch..

The gum base was cut in pieces and heated in a microwave oven. The mixer (Meili, Switzerland) was heated to 40°C and was loaded with the gum base, mannitol and half of the amount of sorbitol particles. Mixing was then started. After 3-4 minutes, the following ingredients were slowly added consecutively

- a further quarter of the amount of sorbitol,

- the maltitol syrup,

- Aspartame™

- Acesulfame-K™.

After another 2 minutes, the flavour containing the Coolant (in Example C4) or the Coolant-y-cyclodextrin complex from Example 1 (in Example 4) were added together with the last quarter of the amount of sorbitol. Mixing was continued for 3 minutes before the mixer was discharged. The chewing gum mass was dusted with talc, laminated on a roller machine (R&S, Linden, Germany) and cut into appropriate pieces.

Example 5 - Sensory evaluations of chewing gum samples

24 hours after the preparation of the chewing gum samples, 10 panelists were asked to chew Example C4 for 40 minutes and after at least 2 hours they were asked to taste Example 4 for 40 minutes. Cooling intensity scores were recorded every minute in the first 10 minutes and every 5 minutes afterwards and rated on a scale from 0 to 10 with the numbers indicating increasing cooling effect. They have the meaning given in Table 2. The results are shown in Figure 1.

Table 3

The difference between chewing gum Examples C4 and 4 is clear. Chewing gum of Example C4 with pure Coolant didn't show distinct cooling effects, as the insoluble Coolant could not be released into the saliva in the oral cavity. However, the cooling effect of chewing gum of Example 4 was much stronger, indicating that the complexed Coolant is released into the saliva and can couple easily with thermo-receptors in the oral cavity.