Carboxylic acid esters of mono- and di-glycerides as a dispersing agent

Field of the invention

The invention relates to the use of carboxylic acid esters of mono- and di-glycerides for the improvement of the dispersibility of powdered products, in particular foodstuff components formulated as dry powders.

Background of the invention

Some dried powders have poor dispersion properties when added to aqueous solvents such as water. Typically, dried powders which fail to fully dissolve in water form lumps, have an undesirable mouthfeel and may have poor sensory characteristics.

In recent years, efforts have been made by the food industry to provide dried powders which have improved dispersion properties without adversely affecting the taste, flavour or mouthfeel of the resulting reconstituted powder.

Soy lecithin and other vegetable lecithin's are glycerol phospholipids, a group of substances coming out as by-products from the refining of vegetable oils. In general, the biggest fractions of glycerol phospholipids are characterised by its chemical structure as being glycerol esterified in the 1-position and in the 2-position with fatty acids, while the 3-position is esterified with a group of phosphate.

Soy lecithin and other lecithins are commonly used as emulsifying, wetting, dispersing and instantising agents. As an instantising agent it finds use in many different types of instant food products, such as sweetened cocoa powder and powdered milk. With the increase in recent years in the growing of genetically modified soybeans it is very difficult, if not impossible, to obtain soy lecithin that is completely GMO-free.

Increasing consumer awareness on food originating from genetically modified plants means that there is an increasing need for completely GMO-free food products. For this reason it is desirable to find alternatives to lecithin as a wetting, dispersing or instantising agent.

Furthermore, lecithins are inevitably connected to substances, which are recognized as being allergens to some people, and food products containing allergens need to have appropriate labelling. For this reason it is desirable to find a non-allergenic alternative to lecithin as a wetting, dispersing or instantising agent.

Lecithins, in particular soy lecithin, have a characteristic smell and taste of their own. To many consumers it is undesirable to have such a smell or taste in the food products that they consume and for this reason also an alternative to lecithin is sought. Another drawback with lecithins is that they are produced under conditions that do not securely prevent contamination with disease invoking microorganisms, such as e.g. salmonella.

Different alternatives have been contemplated in the art, in particular for pharmaceutical formulations. WO 03/013473 discloses an orally deliverable pharmaceutical formulation ' comprising a dispersing agent selected from a number of alternatives to lecithin. None of these alternatives include the dispersing agents as defined in the present invention.

The need for an alternative wetting, dispersing and/or instantising agent is evident in the art. Thus, a wetting, dispersing and/or instantising agent that does not suffer from the drawbacks listed for lecithin was sought by the present inventors.

Summary of the invention

Surprisingly, it was found by the inventors of the present invention that carboxylic acid esters of mono- and di-glycerides possess many of the useful features of lecithin as a dispersing agent without having the same drawbacks. Carboxylic acid esters of mono- and/or di-glycerides are neutral in smell and taste and may be produced under conditions that exclude the contamination with disease invoking microorganisms. They are furthermore not known to be associated with allergens in any way.

Accordingly, a first aspect of the invention concerns a powdered composition comprising a dispersing agent comprising a carboxylic acid ester of mono- and/or di-glycerides and at least one foodstuff component or active pharmaceutical ingredient.

A second aspect of the present invention relates to the use of a dispersing agent comprising a carboxylic acid ester of mono- and/or di-glycerides for the improvement of the wettability, dispersibility and/or solubility of a composition comprising at least one foodstuff component or active pharmaceutical ingredient. Said foodstuff component may be any foodstuff component that can be formulated as a dry powder.

According to a third aspect, the present invention relates to a method of improving the wettability, dispersibility and/or solubility of a composition comprising at least one foodstuff component or active pharmaceutical ingredient, comprising the steps of:

a) Providing a dispersing agent as defined herein, and b) Mixing the dispersing agent with the at least one foodstuff component or active pharmaceutical ingredient.

Detailed description

Definitions

In the context of the present invention the term "powdered composition" relates to a composition of particles, and preferably a dry or a semi-dry composition. A powdered composition may e.g. be a composition wherein the components have been crushed into very fine grains or granular material. Without being bound by a specific definition, a granular material is in general characterised as a conglomeration of discrete solid, macroscopic particles characterized by a loss of energy whenever the particles interact (the most common example would be friction when grains collide). The constituents that compose granular material in general need to be large enough such that they are not subject to thermal motion fluctuations.

The term "active pharmaceutical ingredient" is well known to the person skilled in the art and is used herein in the common meaning of the term. More particularly it refers to any drug substance useful in the diagnosis, treatment or prophylaxis of a disease or medical condition suffered by a mammal, in particular a human, as well as the alleviation, diagnosis, treatment or prophylaxis of symptoms associated with said disease or medical condition.

In the context of the present invention is contemplated the use of a dispersing agent as described herein as a component in a powdered pharmaceutical composition. As an example, an active pharmaceutical ingredient may be intended for intravenous administration, but said pharmaceutical ingredient could be unstable in the solution used for intravenous administration when stored for an extended period. If said pharmaceutical ingredient is stable under dry conditions, it could be stored as a dry powder, but would need to be dissolved/dispersed in a solution before administration. Many active pharmaceutical ingredients suffer from poor solubility in aqueous solutions. Hence, a poorly soluble active pharmaceutical ingredient needing to be dissolved/dispersed rapidly into a solution could advantageously be incorporated into a composition according to the present invention.

Non-limiting illustrative examples of suitable drugs of low water solubility include acetohexamide, acetylsalicylic acid, alclofenac, allopurinol, atropine, benzthiazide,

carprofen, celecoxib, chlordiazepoxide, chlorpromazine, clonidine, codeine, codeine phosphate, codeine sulfate, deracoxib, diacerein, diclofenac, diltiazem, estradiol, etodolac, etoposide, etoricoxib, fenbufen, fenclofenac, fenprofen, fentiazac, flurbiprofen, griseofulvin, haloperidol, ibuprofen, indomethacin, indoprofen, ketoprofen, lorazepam, medroxyprogesterone acetate, megestrol, methoxsalen, methylprednisone, morphine, morphine sulfate, naproxen, nicergoline, nifedipine, niflumic, oxaprozin, oxazepam, oxyphenbutazone, paclitaxel, phenindione, phenobarbital, piroxicam, pirprofen, prednisolone, prednisone, procaine, progesterone, pyrimethamine, rofecoxib, sulfadiazine, sulfamerazine, sulfisoxazole, suϋndac, suprofen, temazepam, tiaprofenic acid, tilomisole, tolmetic, and valdecoxib.

In the context of the compositions of the present invention the term "moisture" refers to compounds or substances that, when subject to a given set of physical conditions such as e.g. room temperature, atmospheric pressure etc, would be in a liquid phase when isolated from said compositions. In particular, "moisture" may refer to water molecules present in the compositions of the present invention. Moisture content may be measured using the "loss on drying" (LOD) test as described in Food Chemistry Code IV, or a direct (Karl Fischer) titration method.

When referring to a "carboxylic acid ester of mono- and/or di-glycerides" and "citric acid ester of mono- and/or di-glycerides" in the context of the present invention, the term is used in its usual meaning as known to the person skilled in the art.

A carboxylic acid (citric acid) ester of mono- and di-glycerides is a compound of the formula I,

OR ₁ H ₂ C

CH OR ₂

H ₂ C

OR ₃ I

wherein at least one of Ri, R ₂ , or R ₃ represents a carboxylic acid (citric acid) component, at least one represents a fatty acid component, and the remainder may be selected from the group consisting of carboxylic acid (citric acid), a fatty acid and hydrogen.

When referring to the terms "carboxylic acid component", "citric acid component" and "fatty acid component" in relation to carboxylic acid esters of mono- and/or di-glycerides as defined herein, it is intended to mean the carboxylic acid, citric acid and fatty acid moieties, respectively, that result from hydrolysis of the carboxylic acid esters of nnono- and/or di-glycerides comprised in the dispersing agent comprised in the compositions of the present invention.

The term "fatty acid" herein is used with the meaning known to person skilled in the art. A fatty acid is generally considered to be a long-chained carboxylic acid containing at least 8 carbon atoms and may be either saturated or unsaturated. In an embodiment of the invention, the fatty acid component of the dispersing agent contains 12 to 22 carbon atoms, more preferably from 14 to 18 carbon atoms, most preferably from 16 to 18 carbon atoms. Natural fatty acids may be derived from naturally occurring fats or oils such as e.g. rapeseed oil.

In a mono-glyceride the fatty acid component may be in either the 1-position or the 2- position, i.e. mono-glycerides may be selected from the group consisting of 1-mono- glycerides and 2-mono-glycerides. Similarly, di-glycerides may be selected from the group consisting of 1,2-di-glycerides and 1,3-di-glycerides. Said groups may be combined in any way, i.e. the carboxylic acid esters of mono- and di-glycerides comprised in the compositions according to the present invention may have a combination of mono- and di- glycerides selected from the group consisting of 1-mono-glyceride and 1,2-di-glyceride, 1- mono-glyceride and 1,3-di-glyceride, 2-mono-glyceride and 1,2-di-glyceride, 2-mono- glyceride and 1,3-di-glyceride, as well as any mixtures thereof.

The terms "wetting agent", "dispersing agent" and "instantising agent" in the context of the present invention are intended to mean a compound or substance that, when present on the surface of a powdered product, improves the wettability, dispersibility and solubility, respectively, of said powdered product. A "dispersing agent" may be said to reduce the interfacial tension between the substrate and the wetting liquid.

In the context of the present invention the term "wettability" in relation to a powdered product is intended to mean the ability of a solid substance to be penetrated by a liquid due to capillary forces. Similarly, in the context of the present invention, the term "dispersibility" refers to the ability of individual powder particles of a powdered product to disperse in or distribute into a liquid. Wettability and dispersibility may be determined according to the international IDF standard 87. Solubility may be determined using the Insolubility Index (ISI) according to IDF standard 129.

When referring to the term "iodine value" in the context of the present invention, it is used in the meaning known to the person skilled in the art. More particularly, the iodine value may be considered a measure of the unsaturation of fats and oils and is expressed in terms of the number of centrigrams of iodine absorbed per gram of sample. The iodine 5 value may be determined according to Wijs, AOAC 17 ^th ed. 41.1.15.

In the context of the present invention, the term "hydrophilic" as applied to the hydrophilic foodstuff components generally means that the foodstuff component is sufficiently attracted to water in an aqueous medium without the need for applying a dispersing agent.

10 In the present context, a foodstuff component may be considered to be hydrophilic if it has a solubility in water of above 0.5 g per 100 g of water. A hydrophilic foodstuff component preferably has a solubility in water of above 1 g, more preferably above 5 g, in particular above 10 g, more preferably above 25 g, most particularly above 50 g, especially above 100 g per 100 g of water.

15

When referring to the "improvement of wettability, dispersibility and/or solubility" in the context of the present invention, it is meant to signify that the wettability and/or solubility measurements according to IDF standards 87 and 129, respectively decrease by at least 5%, preferably at least 10%, more preferably at least 15%, even more preferably at least

20 25%, most preferably at least 50%, and/or that the dispersibility measurement according to IDF standard 87 increases by at least 5%, preferably at least 10%, more preferably at least 15%, even more preferably at least 25%, most preferably at least 50%.

Preferred embodiments

25 The powdered compositions according to the first aspect of the present invention may contain a certain amount of moisture. In particular foodstuff components formulated as dry powders may contain up to 15% (wt/wt) of moisture. Accordingly, in an embodiment of the compositions according to the present invention, said compositions contain less than or equal to 15% (wt/wt) of moisture, preferably less than or equal to 12% (wt/wt) of

30 moisture, and even more preferred less than or equal to 5% (wt/wt) of moisture .

Alternatively, the moisture content of the compositions according to the present invention may be in the range 0.1 to 15% (wt/wt), preferably in the range 0.1 to 12%, such as in the range 0.5 to 10%, more preferably in the range 1 to 7%, most preferably in the range 2 to 5%. In another embodiment, the moisture content of the compositions according to

35 the present invention may be in the range 10 to 15% (wt/wt), preferably in the range 12 to 15%.

In a preferred embodiment, the dispersing agent comprised in the composition according to the present invention comprises at least 75% (wt/wt) of a carboxylic acid ester of mono- and/or di-glycerides, preferably at least 80% (wt/wt), more preferably at least 85% (wt/wt), even more preferably at least 90% (wt/wt), and most preferably at least 95% (wt/wt). Depending on the process for producing the dispersing agent it may not be possible to obtain a product consisting entirely of esters of mono- and/or di-glycerides at a cost efficient price. Therefore the dispersing agent comprising carboxylic acid esters of mono- and/or di-glycerides may furthermore comprise impurities such as unreacted triglycerides and carboxylic acids, glycerol and free fatty acids.

In an alternative embodiment, the composition may further comprise an additional wetting agent. The additional dispersing agent may e.g. be selected from the group consisting of lecithin, e.g. soy lechitin, sodium lauryl sulfate, propylenglycol, and microcrystalline cellulose.

The carboxylic acid component in the dispersing agent comprised in the compositions according to the present invention is preferably a carboxylic acid containing at least one hydroxy group. In another preferred embodiment, the carboxylic acid component contains two or more carboxylic acid groups, such as three acid groups, i.e. a tricarboxylic acid. In a most preferred embodiment, the carboxylic acid component is a hydroxycarboxylic acid, e.g. citric acid.

While it is contemplated by the present inventors that the dispersing agent comprised in the compositions according to the present invention may comprise a carboxylic acid ester of exclusively mono-glycerides or a carboxylic acid ester of exclusively di-glycerides, a preferred embodiment of the compositions according to the present invention comprises a dispersing agent comprising a carboxylic acid ester of both mono- and di-glycerides.

In a particularly preferred embodiment, in the composition according to the present invention, the weight/weight ratio between di- and mono-glycerides is from 3:7 to 9: 1, preferably from 2:3 to 7: 1, more preferably from 5:6 to 4: 1, such as 5:6 to 2: 1, most preferably from 5:6 to 3:2, such as around 1:1.

The fatty acid component(s) of the mono- and/or di-glycerides may originate from various sources. In particular, the fatty acid component(s) may be derived from a naturally occurring fat or oil source selected from the group consisting of rapeseed oil, castor oil, maize oil, cottonseed oil, olive oil, palm oil, safflower oil, sesame oil, soybean oil, sunflower oil, and any mixture thereof and any derivative thereof, preferably from rapeseed oil or a derivative thereof.

The fatty acid component(s) may also be defined in terms of the number of carbon atoms therein. In a preferred embodiment, the fatty acid component(s) may be a saturated or unsaturated C ₁₂ - _H fatty acid, preferably a Q ₄ - _I8 carboxylic acid, most preferably a C _16-18 carboxylic acid.

The fatty acid component(s) preferably have an iodine value of at least 40, more preferably at least 50, most preferably at least 70, such as 70-100.

The amount of dispersing agent in compositions according to the present invention may vary. The person skilled in the art will know how to determine the most desirable amount of dispersing agent in the compositions according to the present invention based on the particular carboxylic acid ester(s) and foodstuff component(s) or active pharmaceutical ingredient(s) present in the composition. It is contemplated by the inventors of the present invention that the amount of dispersing agent in the compositions according to present invention may be between 0.01 and 5% (wt/wt), preferably between 0.05 and 1.5% (wt/ wt).

In a preferred embodiment of the invention, the dispersing agent comprised in the compositions according to the present invention is present on the surface of particles of at least one foodstuff component or active pharmaceutical ingredient. The entire surface of said particles need not be covered by the dispersing agent to improve the wettability and/or dispersibility of said particles, i.e. some surface molecules on said particles may upon wetting with e.g. water be exposed directly to the water molecules rather than only through the molecules of the dispersing agent. In a particularly preferred embodiment, the dispersing agent is present as an entire or partial coating on the surface of particles of at least one foodstuff component or active pharmaceutical ingredient.

It is contemplated by the present inventors that the dispersing agent may be applied in a composition containing more than one foodstuff component or active pharmaceutical ingredient. In such a composition with the dispersing agent present on the surface of particles of at least one foodstuff component or active pharmaceutical ingredient, it may not be necessary to improve the wettability and/or dispersibility of all the components or ingredients. Hence, in an alternative embodiment of the invention, the compositions according to the present invention comprise at least two foodstuff components or active pharmaceutical ingredients, one of said components having the dispersing agent present on the surface of particles thereof, the other of said components not having the dispersing agent present on the surface of particles thereof. Very often the component or ingredient

not having the dispersing agent present on the surface of particles thereof is a hydrophilic component or ingredient.

The compositions according to the present invention preferably comprise at least one foodstuff component. Said foodstuff components may be any foodstuff components that are able to be formulated as dry powders and are preferably selected from the group consisting of cocoa, sugar, such as glucose, sucrose and other sugars known to the skilled person, powdered milk, dried fruit, dried cereals, dried foodstuff protein of animal origin, soups formulated as dry powders, sauces formulated as dry powders, dressings formulated as dry powders, deserts formulated as dry powders, ready-made dishes formulated as dry powders, and foodstuff additives, as well as any mixtures thereof, most preferably powdered milk.

In a most preferred embodiment of the invention, the composition according to the present invention comprises a dispersing agent comprising a citric acid ester of mono- and di- glycerides, wherein said dispersing agent comprises at least 75% mono- and di-glycerides in the ratio 40:60 to 60:40 (wt/wt), and wherein the fatty acid component is derived from rapeseed oil.

The embodiments of the compositions according to the first aspect of the invention as described above are not to be construed as limited to the embodiments explicitly described herein and may be combined in any way possible.

According to a second aspect, the present invention concerns the use of a dispersing agent comprising a carboxylic acid ester of mono- and/or di-glycerides for the improvement of the wettability, dispersibility and/or solubility of a composition comprising at least one foodstuff component or active pharmaceutical ingredient. The use according to this second aspect of the invention is contemplated for any of the dispersing agents and/or compositions as defined for the embodiments of the compositions according to the present invention herein.

According to a third aspect, the present invention relates to a method of improving the wettability, dispersibility and/or solubility of a composition comprising at least one foodstuff component or active pharmaceutical ingredient, comprising the steps of:

a) Providing a dispersing agent as defined herein, and b) Mixing the dispersing agent with the at least one foodstuff component or active pharmaceutical ingredient.

The dispersing agent comprising a carboxylic acid ester of mono- and/or di-glycerides as defined for the present invention may be prepared by a reaction between the carboxylic acid and mono- and/or di-glyceride. As will be known to the person skilled in the art, the ratio between the reactants, the reaction temperature and the reaction time is determining 5 the degree of esterification. Mono- and di-glyceride traditionally is prepared by trans- esterification of tri-glycerides with glycerol, but other processes may be applied

Heating the mixture of the prepared mono- and/or di-glyceride and carboxylic acid performs the esterification to give the carboxylic acid ester of mono- and/or di-glyceride.

10 Mono- and/or di-glyceride may be preheated before the addition of carboxylic acid, and then the heating preferably is continued until reaction temperature is obtained. The temperature of the preheated mono- and/or di-glyceride may generally be 8O ⁰ C to 120 ⁰ C, preferably 90 ⁰ C to HO ⁰ C and more preferably 100 ⁰ C. The reaction temperature may generally be 100 ⁰ C to 160 ⁰ C, preferably 12O ⁰ C 150 ⁰ C and more preferably about 140 ⁰ C.

15 The reaction mixture is typically maintained at a pressure of 10 to about 760 mmHg, more preferably maintained at a pressure form about 20 to 200 mmHg and most preferably about 50 mmHg.

Generally, the esterification reaction may be performed for about 1-20 hours, preferably 5- 20 10 hours and more preferably 8-10 hours.

Prior to and/or during the reaction, the reaction mixture may advantageously be covered with an inert gas such as nitrogen. The water being released during the reaction may continuously be removed from the reaction mixture by evaporating and condensing the 25 water vapour.

Mixing of the dispersing agent and the at least one foodstuff component or active pharmaceutical ingredient may be performed in a manner known to the person skilled in the art. It is for instance commonly known in e.g. the food industry how to prepare 30 "instant" products. Such processes are described in e.g. "Marijana Caric, Concentrated and Dried Dairy Products, VCH Publishers, 1st ed., 1994" and "K. Masters, Spray Drying, John Wiley and Sons, 2002".

Initially, in a preferred method of preparing the compositions according to the present 35 invention, a powder is provided. If the foodstuff component or active pharmaceutical ingredient is initially present as a liquid, such as e.g. liquid milk of a desired fat and milk solids content, it is concentrated using single or multi-effect evaporators. For liquid milk, the milk is concentrated to approximately 40% solids (or 60% moisture) although this may

vary depending on the time of year and milk quality. The concentrated liquid is then dried quickly in a spray drier typically to about 10% moisture content to form the powder.

In a preferred embodiment the dispersing agent may be added at any stage, e.g. for a composition or ingredient initially present as a liquid following spray drying. Typically, however, following spray drying, the powder is conveyed and/or transported to a fluidised bed dryer or driers. In the preferred method, the dispersing agent is added to the powder during or before the fluidised drying step when the moisture content of the powder is between 5 -10% or less. At about 10% moisture content, the powder has optimum "flow" or circulation characteristic for the fluidised bed dryer. At this stage, the powder will generally have a crystalline or glassy, or semi-solid or solid form.

The dispersing agent is preferably added to the powder as a "liquid stream" under sufficient pressure to form a spray, or in combination with compressed air to form a mist which adheres to the individual particles and thus coats the food powder.

The powder (including the dispersing agent) may then be further dried to a final moisture content of about 2% to 10% in the same or a different fluidised bed dryer for packaging for commercial sale as a dehydrated food powder and/or food product. This results in a dried powder with desirable wettability, dispersilbility and/or solubility.

Alternatively the dispersing agent may be added to dried powder, typically having a moisture content of 0.1% to 5%. Dried powder may include powder dried by a prior fluidised bed drying step.

The drying step using the fluidised bed dryer outlined above is not essential to the overall workings of the invention. The fluidised bed drying is used in the preferred embodiment for two reasons: firstly to utilise the tumbling action of the fluidised bed dryer to promote dispersion of the carboxylic acid esters of mono- and/or di-glycerides around powder particles; secondly to dry the powder to form the dehydrated food powder ready for retail sale and packaging. It will be appreciated that the dispersing agent may simply be added and mixed with the bulk powder resulting from spray drying and stored for drying or use at a later date. The mixing can be performed in any food or powdermixer known in the art. As an example may be mentioned the Vrieco-Nauta® conical mixer from Hosokawa Micron B. V. Alternatively, the mixing can be performed in the fluidised bed dryer provided that the powder with dispersing agent is removed from the dryer before drying takes place, or conveyed through the dryer with little or no drying or loss of moisture taking place. However, in the preferred embodiment the mixing and drying steps are achieved using the fluidised bed dryer to dry the powder to the dehydrated food powder.

Carboxylic acid esters of mono- and/or di-glycerides have an additional advantage in that they can be added at temperatures generally higher than normal lecithin based blends, allowing for the thermal destruction of pathogenic and other micro-organisms.

The higher temperature tolerance of the carboxylic acid esters of mono- and/or di- glycerides allows the dispersing agent to be added to powders at much higher temperatures, and at any time after injection of concentrate into the spray dryer. The higher temperature is advantageous since the viscosity of the carboxylic acid ester of mono- and/or di-glycerides is inversely proportional to the temperature. A lower viscosity will cause a spray of smaller droplets, thus yielding a better coating of the powder.

The carboxylic acid esters of mono- and/or di-glycerides are easier than lecithin to remove with hot water and surfactants. This allows for easier cleaning in place (CIP) and reduces the risk of microbial build-up.

The carboxylic acid esters of mono- and/or di-glycerides may be applied in combination with a carrier. The selection of a carrier may be made on the basis of a variety of characteristics including viscosity, flavour, ingestibility, miscibility and compatibility with the carboxylic acid esters of mono- and/or di-glycerides. The carrier will preferably be adapted to suspend, stabilise, or dissolve the ingredient(s) to provide an additive composition of desired features.

It will be appreciated, however, that it is not essential to preblend the carboxylic acid esters of mono- and/or di-glycerides with a carrier such as vegetable oil, animal fat, nonflammable solvent or the like. Removing a carrier reduces the costs associated with blending, and reducing the risks of physical, chemical or microbial cross contamination. However it may be appropriate to use a carrier where the carboxylic acid esters of mono- and/or di-glycerides are added under such conditions (such as at high viscosity) so as to prevent the dispersing agent from forming a relatively homogenous coating of particles.

It will be appreciated that other compounds may be added to the powder including flavourings, sweeteners, colourings or the like.

Examples

Example 1

A range of different citric acid esters may be prepared. In a first series of preparations, citric acid esters with the fatty acid component derived from rapeseed oil and a varying ratio between mono- and di-glycerides may be prepared. The mono- and di-glycerides may be prepared as described above and the ratio between mono- and di-glycerides may be controlled by adjusting the ratio between the reactants, tri-glyceride and glycerol, as well as the reaction temperature and reaction time.

The esters may be prepared with the following ratios (wt/wt) between di- and mono- glycerides: 30:70, 40:60, 50:50, 60:40, 70:30.

In a second series of preparations, citric acid esters with a 50:50 ratio (wt/wt) between di- and mono-glycerides may be prepared. In this second series, the fatty acid component may be derived from: rapeseed oil, castor oil, maize oil, sunflower oil, soybean oil, safflower oil, sesame oil, olive oil, cottonseed oil, or palm oil.

Glycerides derived from rapeseed oil in a mass ratio of mono-glyceride and di-glyceride of approximately 50:50 were charged to a reaction flask. The reaction flask was equipped with a mechanical stirrer, nitrogen inlet, vacuum capabilities to 1 mmHg, steam outlet, thermometer and temperature controlled heating mantel.

The glycerides were heated until 100 ⁰ C with good agitation. Citric acid, 20% in weight, was added to the glyceride, and then the heating was continued until 14O ⁰ C. After the addition of citric acid, the pressure in the reaction flask was gradually reduced to 50 mmHg. The reaction was continued for 5 hours. Then the reaction mixture was cooled to below 80 ⁰ C before discharge.

The citric acid ester of mono- and di-glycerides thus produced was applied in Example 2.

Example 2

A dispersing agent according to Example 1 may be mixed with powdered foodstuff components or active pharmaceutical ingredients in a fluidized bed according to the method described above. Components or ingredients to be tested include cocoa powder combined with sugar, powdered milk, soup powder, sauce powder, and acetyl salicylic acid.

The results for the wettability, dispersibility and solubility measured according to IDF Standards 87 and 129 of powdered foodstuff components with soy lecithin and a dispersing agent prepared in Example 1, and without dispersing agent are given in table 1 and 2 for cocoa powder combined with sugar and dextrose, and powdered milk, respectively.

Table 1

n.d = not determined

Table 2

AMF: Anhydrous Milk Fat

The results show that there is a significant improvement of wettability, dispersibility and solubility when the powdered foodstuff components are mixed with carboxylic acid esters of mono- and/or di-glycerides, and that the results obtained with these esters are at least comparable to results achieved with lecithin.