An encapsulation is a process by which one or more active ingredients are coated with, or entrapped within, another material or system. In the flavor industry, the encapsulation of flavor ingredients serves to retain the aroma in a food product during storage, protects the flavor from undesirable interactions with the food, minimizes flavor/flavor interactions, guards against either light induced reactions or oxidation, and provides a controlled release of the flavor.

In this industry, the most common processes for producing encapsulated products are spray-drying and, to a lesser extent, extrusion and coacervation.

Background Art Spray-drying is a well-known useful technique to stabilize flavors by encapsulating them in a solid form, suited to many applications.

In spray-dried powders, an active ingredient such as a flavor or a fragrance, usually hydrophobic, is entrapped as liquid droplets in a solidified matrix of a dehydrated carrier, generally consisting of carbohydrates, such as starches, hydrolyzed starches (maltodextrin), chemically modified starches, emulsifying polymers (gum arabic) and in certain instances monomers and dimers of simple aldohexoses, or any combination thereof. Conventional spray-drying techniques are perfectly well documented in the prior art. See for example Spray-Drying Handbook, 4"ed., K. Masters, (1985) or other reference books on the subject-matter.

The method for the preparation of a spray-dried powder typically first comprises dispersing a carrier in water, and then mixing this dispersion with a flavor before homogenizing to form an oil-in-water emulsion. The emulsion is then spray-dried to produce a powdered flavor.

Flavors are traditionally spray-dried in water-soluble carbohydrate matrices. As these matrices dissolve in water readily, the most common applications of the corresponding powdered flavors are dry beverage formulations. However, other applications in the flavor industry as well as in other fields such as the perfumery or the pharmaceutical domains require spray-dried products having a behavior in an aqueous environment different from traditional spray-dried powders. In particular, powders which are able to dissolve in water more slowly than most spray-dried products available today and which may even require a mechanical trigger for the release of the active ingredient encapsulated in the matrix, could be very useful for many applications.

Means to improve the dispersion of typical spray-dried powders have already been described in the prior art. Agglomeration constitutes such a means and finds applications for instance in instant coffee. However, this process does not suit all applications.

Now, we have been able to establish that a particular ingredient can be added to the carrier constituting the matrix of a spray-dried product, and, in combination with a wall-forming carbohydrate material, surprisingly improve the behavior of the powder in an aqueous or highly moist environment. This ingredient is agar agar.

Agar agar is a hydrocolloid, the physical properties of which are well known in the art. More particularly, it has a widespread use in foods as a stabilizer, thickener, humectant and surface finisher.

Some patent literature discloses the spray-drying of agar itself to provide it in a solid form. On the other hand, agar is often cited as part of the list of encompassing materials susceptible of constituting carriers in an encapsulation system. As an example, one can cite WO 98/33394 which discloses the mixture of a bulking agent with a hydrocolloid in the form of a solid powder which is used as a stabilizing agent in a wide variety of products. However, no document from the prior art has ever pointed out or even suggested the possibility of using agar in a spray-dried composition for a specific purpose, when used in defined amounts and in combination with a carbohydrate material.

Yet, we have now been able to establish that, in combination with the main carrier material, namely a carbohydrate, and when used in specific amounts, agar agar is an advantageous co-carrier material for a composition intended to be spray-dried. In an

unexpected manner, this novel composition proved to be responsible for a complete change in the product's behavior, in an aqueous or highly moist environment, and as regards the release characteristics of the active ingredient there-encapsulated, compared with conventional spray-dried powders.

Disclosure of Invention One object of the invention is thus a novel spray-dried composition, comprising one or more active ingredients dispersed in a carrier which comprises at least one wall- forming carbohydrate material and from 1 to 30% by weight of agar agar, relative to the dried weight of the composition.

What is meant here by"active ingredient", is a liquid ingredient, preferably hydrophobic, which is sought to be protected by way of solid encapsulation. It may include volatile perfuming or flavoring ingredients, as well as other kinds of ingredients such as pharmaceutical actives for instance.

The system of the invention presents many advantages. While a typical spray- dried product dissolves instantly in water, the composition according to the present invention behaves in a totally different manner in such a medium and makes it possible to provide a controlled release of the encapsulated active ingredient.

A second object of the present invention is a method for the preparation of such a spray-dried composition, and a further object, its use for the flavoring or perfuming of consumer products such as foods, beverages, or perfuming compositions.

Finally, the spray-dried powder of the invention can also be advantageously used as an intermediate product or starting product for a double-encapsulation method, i. e. as a solid product susceptible of being subjected to a further encapsulation such as an extrusion in a glassy matrix to provide a granular delivery system, or to a second spray-drying operation in a distinct or similar matrix.

More objects, aspects and advantages of the invention will become apparent from the detailed description hereafter.

The present invention thus concerns a composition in the form of a spray-dried powder, comprising one or more active ingredients dispersed in a carrier, wherein said carrier comprises at least one wall-forming carbohydrate material and from 1 to 30% of

agar agar, relative to the dried weight of the composition. In another embodiment, the proportion of agar agar in the composition can be limited to 1 to 20%, or even to 1 to 15% by weight, relative to the dried weight of the composition.

The spray-dried product of the invention turned out to be very useful in particular in an aqueous environment, where it provides a release of the active ingredient which is quite distinct from typical systems known in the prior art. More particularly, the addition of a certain amount of agar agar in the carrier matrix, in combination with a wall-forming carbohydrate material, proved to provide a structure which swells almost instantly upon hydration and forms a gel, wherein the mobility of the active ingredient, in the form of oil droplets, is restricted. As a consequence, even when excess water is present, the gel containing the oil droplets remains intact.

Therefore, if the hydrated powder particles are left undisturbed, i. e. are not subjected to constant shear at room temperature, they can retain their integrity for at least 2 weeks, after which the release of the oil from the hydrated particles, when deformed under pressure, is observable. Thus, while typical spray-dried products dissolve instantaneously in an aqueous environment, providing an instant release of the encapsulated active ingredient, the system of the invention provides a controlled release of the active substance. Under another kind of trigger such as shear force or heat, the active substance will be released from the dry powder.

The spray-dried powder of the invention also presents a particularly advantageous stability in a medium of high relative humidity. Therefore, contrary to powders known up to date, the delivery system of the invention can be stored or be subjected to transportation while protecting in an effective way the active ingredient there-encapsulated.

The carrier of the spray-dried composition comprises at least one wall-forming carbohydrate material and from 1 to 30% of agar agar which may be in a partially hydrated form. This combination is responsible for the technical effect here-above described.

Suitable wall-forming carbohydrate materials are substrates such as polyvinyl acetate, polyvinyl alcohol, dextrines, natural or modified starch, pectins, xanthanes, alginates, or yet cellulose derivatives such as for example carboxymethyl cellulose, methyl cellulose or hydroxyethylcellulose. In one particular embodiment of the

invention, the carbohydrate material is selected from the group consisting of a maltodextrin, a corn syrup, a chemically modified starch, a hydrogenated starch hydrolysate and a succinylated or hydrolyzed starch.

The composition of the invention typically comprises from 70 to 99% by weight, relative to the dried weight of the composition, of wall-forming carbohydrate material.

Preferably, it contains from 40 to 80% of carbohydrate material.

In a preferred embodiment, the matrix composition further comprises a plasticizer such as a sugar or sugar derivative, such as sucrose, glucose, lactose, levulose, fructose, maltose, ribose, dextrose, isomalt, sorbitol, mannitol, xylitol, lactitol, maltitol, pentatol, arabinose, pentose, xylose, galactose. Typically, the compositions of the invention may comprise from 0.01 to 50% by weight, relative to the weight of the dried product, of plasticizer.

An agar agar matrix, futher comprising maltodextrin in admixture with one of the sugars mentioned above, in particular sucrose, is particularly appreciated.

In addition to carbohydrates and plasticizers, the composition of the invention may comprise an emulsifier intended to promote a homogeneous mix of the oil in the carbohydrate based mixture before spray-drying. The nature and proper amount of the emulsifier can be critically assessed by the process operator without undue experimentation. Typically, proportions from 1 to 30% by weight, relative to the dried weight of the composition, can be used.

Many suitable emulsifiers are known in the commerce. Typical examples include soya lecithin, Capsule (modified maize starch from National Starch), citric acid esters of fatty acids and emulsifying polymers such as gum arabic, but other suitable emulsifiers are cited in reference texts such as Food Emulsifiers and their Applications, 1997, edited by G. L. Hasenhuettl and R. W. Hartel, USA.

Finally, the composition of the invention, which is initially in the form of an aqueous emulsion, contains, before being spray-dried, from 50 to 90% of water, preferably from 60 to 85% by weight of water, relative to the total weight of the emulsion.

The active ingredient dispersed in the carrier of the spray-dried composition of the invention will preferably be a hydrophobic flavor or fragrance ingredient or composition of current use. However, the polarity or aqueous solubility of the active

ingredient may be chosen as a function of the desired retardation of the release for a given application. In fact, more hydrophilic components will be released faster, as they are able to partition in the outer aqueous phase.

The terms"flavor and fragrance ingredient or composition"as used herein are deemed to define a variety of flavor and fragrance materials of both natural and synthetic origin. They include single compounds and mixtures. The composition of the invention can encapsulate volatile or labile components in liquid form, preferably hydrophobic. Specific examples of such components may be found in the current literature, e. g. in Fenaroli's Handbook of Flavor Ingredients, 1975, CRC Press; Synthetic Food Adjuncts, 1947 by M. B. Jacobs, edited by Van Nostrand; or Perfume and Flavor Chemicals by S. Arctander 1969, Montclair, N. J. (USA). These substances are well known to the person skilled in the art of perfuming, flavoring, and/or aromatizing consumer products, i. e. of imparting an odor and/or a flavor or taste to a consumer product traditionally perfumed or flavored, or of modifying the odor and/or taste of said consumer product.

Natural extracts can also be encapsulated into the system of the invention; these include e. g. citrus extracts such as lemon, orange, lime, grapefruit or mandarin oils, or coffee, tea, mint, cocoa, vanilla or essential oils of herbs and spices, amongst other.

The proportions of active ingredient in the composition are comprised between 0.1 to 60% by weight, relative to the dried weight of the composition. In a particular embodiment, the proportion of the active ingredient is comprised between 20 and 50%.

Another object of the invention is a method for the preparation of a spray-dried powder, which comprises the steps of emulsifying the active ingredient with an aqueous solution of the matrix carrier comprising at least one wall-forming carbohydrate material and from 1 to 30%, or from 1 to 20% or even from 1 to 15% of agar agar; homogenizing the emulsion and spray drying the latter to form a particulate product.

One particular advantage of the process according to the invention lies in the fact that the compositions comprising a combination of agar agar with a carbohydrate, as here-described, demonstrate a retention of the active ingredient (oil) which is advantageously not affected by a variation in the solid content of the starting aqueous emulsion. More particularly, in classical spray-drying processes, a high dilution rate, useful to provide monodispersity of the powder, must be balanced with the fact that the

higher is the dilution rate, the lower will be the flavor retention. It is furthermore established that 10% lower solid content in the initial aqueous emulsion should result in noticeably decreasing the flavor retention after spray-drying. Now, it turned out in the present case that, as shown in the examples below, the flavor retention of the product of the invention is not affected by the dilution rate, or solid content in the aqueous emulsion introduced into the spray-drier. In other words, high dilution rates may be employed in order to get a good monodispersity of the powder without provoking any drawback on the flavor retention, which is a totally unexpected result.

The spray-drying apparatus used in the process of the invention can be any of the various commercially available apparatus. Examples of spray-drying apparatuses are <BR> <BR> the Anhydro Dryers (origin: Anhydro Corp. of Attleboro Falls, Mass. ), the Niro Dryer<BR> (manufactured by Niro Atomizer Ltd. , Copenhagen, Denmark), or a Leaflash apparatus (origin: CCM Sulzer). Preferably a spray-drier with a pressure nozzle is used.

The process will be described in a more detailed manner in Example 1.

However, the parameters characteristic of a spray-drying process are well known in the art and can be easily adjusted by a skilled person in the art.

The particulates of the invention have typically a size comprised between 50 and 70 im and a bulk density comprised between 0.4 and 0.6 g/cm3. However, a skilled person in the art knows well that the granulometry and the bulk density of the resulting dry powders can be adjusted by selecting the nozzle pressure until the powder having the desired flowability is obtained.

The spray-dried powders prepared according to a process of the invention can be utilized as such in applications, for instance for the perfuming or flavoring of compositions wherein a release is induced by shear or heat. However, they also can be advantageously used as starting materials to be subjected to further processing, before being used as delivery systems in a variety of applications.

In particular, in one embodiment of the invention, the spray-dried particles obtained by the method here-above described, are further encapsulated in an extruded glassy matrix which may be formed from one or more carbohydrate materials or which may just comprise a plasticizer and an emulsifying agent, in order to produce a glassy matrix with an improved thermal stability. US 5,087, 461, the contents of which is hereby included by reference, describes and exemplifies an encapsulation method of a

spray-dried composition by way of extrusion. This process leads to narrow rods having a diameter in the range of 0.3 to 3 mm.

Apart from the extrusion, other kinds of encapsulation processing, following the spray-drying, are possible. The powder obtained can for instance be submitted to a second spray-drying, thus providing a two-stage spray-dried product. This technique in particular, as well as multi-stage spray-drying in general, are described by W. J. Coumans, P. J. A. M. Kerkhof and S. Bruin in Drying Technology, Vol. 12 (1 and 2), (1994), the teaching of which is hereby included by reference.

These examples are not restrictive of the encapsulation techniques which can be used for further processing of the spray-dried powder obtained according to the present invention, notably with the aim of increasing the size of the particles, or improving a particular characteristic of the powder, in order to rend it suitable for specific applications.

The products of the invention, namely the spray-dried powder as such, as well as the spray-dried compositions further subjected to a second kind of encapsulation can be advantageously used for instance for the perfuming or flavoring of food compositions in particular.

Therefore, the delivery systems of the invention can be used in applications such as chewing gums or chewing sweets, savoury food or baking in the field of flavours.

Similarly the field of perfumery comprises many applications where this kind of encapsulation systems may be very useful. For instance all kinds of deodorants and antiperspirants constitute suitable applications for a perfuming delivery system with a controlled release of the perfuming ingredient and wherein the integrity of the latter is desirable until consumer use of for a certain period of time.

The powder of the invention may also be advantageously used for perfuming powder bases such as detergent bases. In fact, as shown in a comparative example below, the encapsulation system here-disclosed presents a very good stability towards moisture or relative humidity and these products can therefore be stored during a long period of time before being used, without being subjected to a degradation of the encapsulated perfume.

In those applications, the compositions of the invention provide a flavor or fragrance retention of up to 85% after the encapsulation process, at a fix level as high as

50%, and in an unexpected manner, the flavor retention being independent of the solid content of the aqueous emulsion introduced into the spray-drier. Moreover, the product hydrates very slowly in water and does not dissolve up to two weeks.

The invention will be now described in a more detailed manner in the examples below, wherein the temperatures are indicated in degrees Celsius and the abbreviations have the usual meaning in the art.

Modes of Carrying out the Invention Example 1 Preparation of a spray-dried composition according to the invention Formulation: Ingredients Grams % dry Maltodextrin 18DE 1729 24.70 Sucrose 1729 24.70 Agar agar 700 10.00 Lemon oil 2800 40.00 Lecithin 42 0.60 Water 13600 Total 100.00 1) origin: Firmenich Citrus Center, Florida, USA Preparation : A batch was prepared by hydrating agar agar in water (approximately 10% solids level) and subsequently mixing it with the rest of the ingredients in a stainless kettle equipped with pneumatic agitation. The batch temperature was maintained at 65-70°. When the contents of the kettle were uniform, it was homogenized at 7000 kPa.

The prepared feed was dried with a Leaflash apparatus characterized by the respective inlet/outlet temperatures of 180/80° ; a feed pressure of 17x103 Pa; and a nozzle 70/216 (spraying system) (diameter of spray orifice/spinner nozzle).

Samples were collected and analyzed for oil content by steam distillation. The flavor retention of the particulates after the process was of 85% (solid content of the aqueous emulsion introduced into the spray-drier of 33.98%).

Hydration characteristics and oil droplets release were investigated by microscopy.

Thus, after 2 weeks in water, no oil coming out of the powder was observed. The particulates were intact.

Example 2 Preparation of a spray-dried composition according to the invention Formulation: Ingredients Grams % dry Maltodextrin 18DE 1379 19.70 Sucrose 1379 19.70 Agar agar 700 10.00 Lemon oil 3500 50.00 Lecithin 42 0.60 Water 15200 Total 100.00 1) see Example 1 Preparation: The spray-dried powder was prepared as described in Example 1.

The final product (after the process) had a flavor retention of 87.80% (solid content of the aqueous emulsion introduced into the spray-drier of 31.53%).

No oil droplets diffused from the particles after 2 weeks in water.

Example 3 Preparation of a spray-dried composition according to the invention Formulation: Ingredients Grams % dry Maltodextrin 18DE 1554 22.20 Sucrose 1554 22.20 Agar agar 1050 15.00 Lemon oil 2800 40.00 Lecithin 42 0.60 Water 23200 Total 100.00 1) see Example 1 Preparation: The spray-dried powder was prepared as described in Example 1.

The final product (after the process) had a flavor retention of 85.30% (solid content of the emulsion introduced into the spray-drier of 23.18%).

No oil droplets diffused from the particles after 2 weeks in water.

Example 4 Preparation of a spray-dried composition according to the invention Formulation: Ingredients Grams % dry Maltodextrin 18DE 798 11.40 Sucrose 1554 22.20 Agar agar 1050 15.00 Gum Arabic 798 11.40

Lemon oil 2800 40.00 Water 18200 Total 100.00 1) see Example 1 Preparation: The spray-dried powder was prepared as described in Example 1.

The final product (after the process) had a flavor retention of 87.00% (solid content of the emulsion introduced into the spray-drier of 27.78%).

No oil droplets diffused from the particles after 2 weeks in water.

Example 5 Preparation of a spray-dried composition according to the invention Formulation: Ingredients Grams % dry Maltodextrin 18DE 2079 29.70 Sucrose 2079 29.70 Agar agar 700 10.00 Fragrance 2100 30.00 Lecithin 42 0.60 Water 13600 Total 100.00 1) origin: Firmenich SA, Geneva, Switzerland Preparation: The spray-dried powder was prepared as described in Example 1.

The final product (after the process) had a flavor retention of 100% (solid content of the emulsion introduced into the spray-drier of 33.98%).

No oil droplets diffused from the particles after 2 weeks in water.

Example 6 Spray-dried composition of the invention, further extruded in a glassy matrix A spray-dried composition was prepared as described in Example 1 from the following formulation: Ingredients % dry Maltodextrin 18 DE 84 Agar agar 5 Orange oil 1 Citrem 5 Neobee 5 Total 100 The obtained powder was extruded under 2x105 Pa pressure through a die plate with 0.8 mm diameter holes at a temperature of 95°.

Example 7 Comparative example on the stability of a spray-dried composition according to the invention, in a detergent base Two spray-dried compositions having the following formulations were prepared according to the method described in Example 1 : Formulation A : Ingredients Grams % dry Maltodextrin 18DE 2865 38.20 Sucrose 2865 38.20 Perfume composition 1500 20.00

Agar agar 225 3.00 Lecithin 45 0.60 Water 9600 Total 100.00 1) composition consisting of a mixture of benzyl acetate, phenylethyl acetate, cyclamen aldehyde, Lilial (origin : Givaudan-Roure, Vernier, Switzerland) and hexyl salicylate; each ingredient being present in the same weight percentage in the composition Formulation B : Ingredients Grams % dry Maltodextrin 18DE 2977.5 39.70 Sucrose 2977.5 39.70 Perfume composition 1500.0 20.00 Lecithin 45.0 0.60 Water 9600.0 Total 100.00 1) see Formulation A Each powder was independently admixed with a standard European detergent powder with percarbonate-TAED bleaching system. After a four weeks storage at 37° and 70% relative humidity, the two compositions were respectively separated from the detergent, dissolved in water, and diluted with acetonitrile and 2-heptanone. 1 G of the solution thus obtained was dried over 5 g of Na2S04 and the residual liquid phase was analysed by a standard GC-MS analytical method to determine the residual quantity of the various perfuming ingredients. The results were compared with those obtained with a reference detergent, stored for four weeks at 3°, on which the perfume composition was directly sprayed-on. The results are summarised in Table 1.

Table 1 : Percentage of perfume ingredients recovered after storage for four weeks at 37° and 70% RH Perfuming Sprayed-on Formulation B Formulation A (3% ingredient detergent powder (no agar agar) of agar agar) Benzyl acetate 3 6 6 Phenyl ethyl acetate 10 18 23 Cyclamen aldehyde 31 45 67 LilialW 0. 0 10 Hexyl salicylate 25 48 100

The results reported in Table 1 demonstrate the superiority of the spray-dried composition comprising agar agar which, after a month period of storage, contains the highest proportion of perfuming ingredients which have not been decomposed.