WO2019219589A1

WO2019219589A1 - Composition

Info

Publication number: WO2019219589A1
Application number: PCT/EP2019/062179
Authority: WO
Inventors: Lena HECHT; Vivianne MONNIER; Matthias Schultz
Original assignee: Givaudan Sa
Priority date: 2018-05-14
Filing date: 2019-05-13
Publication date: 2019-11-21
Also published as: GB201807768D0

Abstract

Stable emulsions comprising tea seed saponins, an oil phase and a water phase, wherein the oil phase is dispersed in the water phase in form of droplets, said emulsion being suitable for the preparation of transparent flavoured beverages, and a method to prepare said stable emulsions.

Description

Composition

This disclosure relates to flavour emulsions, to methods of preparing them, and to transparent beverages comprising said emulsions.

Many flavouring agents used for the preparation of beverages contain essential oils and other water insoluble constituents. Dissolving or dispersing such flavouring agents when preparing a beverage would result in phase separation. To prepare transparent beverages or at least almost transparent beverages, the insoluble flavour constituents would need to be removed, resulting in reduced impact and authenticity of the flavour, or the flavour would need to be dispersed and stabilized in the form of an emulsion. The appearance of the beverage, i.e. whether it is transparent or cloudy, would mainly depend on the size of the emulsion droplets. While emulsion droplet diameters above about 200 nm would cause the beverage to be perceived as cloudy, decreasing droplet diameters from about 190 nm down to about 160 nm would result in hazy, and, at droplet diameters of about 120 to about 150 nm and below, to completely clear beverages.

Emulsifiers are naturally required to make such emulsions, and, as the products are consumables, the emulsifiers must comply with Government regulations concerning such products. Furthermore, a major trend in the beverage industry is to use emulsifiers that are perceived by consumers as natural and/or derived from food or plants that are consumed or associated with food and beverages. They should also not be chemically modified or processed in a way that changes their natural composition.

Thus, the desire is to find emulsifiers fulfilling all those requirements with appropriate emulsifying efficiency. Some traditional emulsifying hydrocolloids perceived as natural and unprocessed include gum Arabic, gum ghatti, gum tragacanth, fenugreek gum, mesquite gum, and sugar beet pectin. Unfortunately, these do not permit the attainment of a minimum particle diameter of 190 nm maximum. Thus, a beverage prepared using an emulsion based on such traditional emulsifiers will appear cloudy.

Typical low molecular weight emulsifiers are being used to prepare emulsions for transparent beverages. Typical food grade emulsifiers of that kind belong to the groups of polyglycerol fatty acid esters, sucrose fatty acid esters and polysorbates. However, while enabling the preparation of emulsion droplets sufficiently small for transparent or clear beverages, they have been subjected to an esterification step and are therefore recognised as chemically modified substances.

More recently, saponins have been described in the art as a new category of natural emulsifiers. Quillaja saponins, whose molecular weight lies between those of low molecular weight emulsifiers and gums, in particular have been found to be useful for producing beverage emulsions with adjustable droplet diameter for the preparation of clear as well as cloudy beverages. They combine the emulsifying efficiency of low molecular weight emulsifiers with the desired naturalness and long-term stabilizing properties of the hydrocolloids.

Quillaja saponins are extracted from the bark and wood of the soap bark tree ( Quillaja saponaria), a plant not normally consumed or associated with food and beverages.

Furthermore, soap bark trees are mainly grown in some areas in Chile and Peru, and, considering the increased desirability as an emulsifier for a broad range of applications, it may be questionable if sustainable supply of quillaja extracts will be guaranteed in the future.

Therefore, there is a constant need to find alternative emulsifiers with equal or better performance for the preparation of flavoured compositions, and which are suitable for the preparation of transparent beverages.

Extensive test of saponins obtained from plants have been made. For example, the use of saponins from ginseng extracts and grape seed extracts did not result in stable emulsions at all, namely the separation of the water and oil phases was observed already after 1 day. Tests with berry extracts (Sapindus mukorossi), fenugreek seed extracts, extracts from leaves of green tea, licorice and Yucca extracts resulted in stable, but cloudy emulsions which, when diluted, did not lead to transparent beverages.

While most of the natural emulsifier do not solve the underlying problem, namely the preparation of flavoured transparent beverage, surprisingly it was found that the use of tea seed saponins does result in stable emulsions which, upon dilution gives transparent and stable beverages. Thus, there is provided in a first aspect a stable emulsion comprising tea seed saponins, an oil phase and a water phase, wherein the oil phase is dispersed in the water phase in the form of droplets, said emulsion being suitable for the preparation of transparent flavoured beverages.

By“transparent” we mean a turbidity of 20 NTU or less, e.g. 15 NTU or less, 10 NTU or less. The abbreviation NTU stands for Nephelometric Turbidity Unit, a unit of turbidity well-known to and widely used by the art and measured, for example, by a Hach 2100N turbidimeter (ex Hach Company), using the instrument as per the instructions.

Liquids with a turbidity value from about 20 NTU or smaller (e.g. about 15 NTU, such as 15 NTU or smaller, or about 5 NTU) are described as slightly hazy to fully transparent, i.e. as transparent as water. By“hazy” is meant a liquid in a bottle which is perceived as transparent by the eye, but depending on the size of the bottle (the length of the light path), an image behind the bottle would be perceived as being somewhere between from completely sharp and slightly distorted. Formazin suspension standards having a turbidity in the range of 1 to 100 NTU according to EN ISO 7027 may be obtained, for example, from Macherey-Nagel.

Beverages having turbidity values of about 20 NTU are slightly hazy. Beverages having turbidity values of about 10 NTU and smaller are fully transparent.

Emulsions capable of providing such transparent to slightly hazy beverages have Z-average oil droplet diameter of about 190 nm or smaller. In one embodiment the Z-average diameter of the oil droplets is about 170 nm or less, preferably about 150 nm or less.

The Z-average diameter of the oil droplets is determined by Dynamic Light Scattering (DLS), a method well known to and widely used by the art.

The Z-average diameter of the oil droplets is routinely obtained by measuring the fluctuation of the scattering intensity produced by the Brownian motion of the emulsion droplets in the emulsion. Typically, the measurement is performed at T = 20 °C after dilution of emulsion in water by a dilution factor or 500 to 1000 (e.g. 1 -2 g emulsion in 1 L deionized water). By“stable” in the context of this invention is meant that the Z-average diameter of the oil droplets of the emulsion remains 190 nm or smaller during 1 month storage at a temperature of about 40 °C, or upon dilution.

In another embodiment, there is provided an emulsion as described hereinabove further comprising one or more flavour ingredients.

Examples of suitable flavour ingredients include vanillin, cinnamic aldehyde, 1 ,1 - diethoxyethane; 3-hydroxybutan-2-one; 1 -phenylethanone ; (Z)-oxacycloheptadec-l 0-en-2- one; benzaldehyde; 2-methylpropyl acetate; 2-methylpropyl 2-methylbutanoate; butanal; butyric acid; 2-methylpropanoic acid; 2-methyl-5-prop-1 -en-2-ylcyclohex-2-en-1 -ol; (2E)-3- phenylprop-2-enal; (E)-3,7-dimethylocta-2,6-dienal; 3,7-dimethyloct-6-enal; 3,7-dimethyloct-6- en-1 -ol; (E)-1 -(2,6,6-trimethylcyclohexa-1 ,3-dien-1 -yl)but-2-en-1 -one; 6-pentyltetrahydro-2H- pyran-2-one; 5-hexyloxolan-2-one; decanal; chroman-2-one; methyl 2- (methylamino)benzoate; dimethyl sulfide; oxydibenzene; 1 -methyl-4-prop-1 -en-2- ylcyclohexene; 5-octyloxolan-2-one; ethyl acetate; ethyl butanoate; ethyl 2-methylpropionate; ethyl 3-phenylprop-2-enoate; ethyl decanoate; 6-ethyl-1 ,5,5-trimethylbicyclo[2.2.1 ]heptan-6- ol; ethyl formate; ethyl heptanoate; ethyl hexanoate; ethyl 3-hydroxybutanoate; ethyl 3- hydroxyhexanoate; ethyl 2-methylbutanoate; ethyl octanoate; ethyl 3-methylbutanoate; ethyl propionate; 4-ethylphenol ; pent-1 -en-3-one; 2-methyl-5-propan-2-ylcyclohexa-1 ,3-diene;

7,1 1 -dimethyl-3-methylidenedodeca-1 ,6,10-triene; 2-ethyl-4-hydroxy-5-methylfuran-3-one; (E)-3,7-dimethylocta-2,6-dien-1 -ol; (E)-3,7-dimethylocta-2,6-dien-1 -yl acetate; hexanal;

hexaoic acid; E-hex-2-enal; (Z)-hex-3-en-1 -ol; (Z)-hex-3-en-1 -yl acetate; (E)-4-(2,6,6- trimethyl-1 -cyclohex-2-enyl)but-3-en-2-one; (E)-4-(2,6,6-trimethylcyclohex-1 -en-1 -yl)but-3-en- 2-one; 3,7-dimethylocta-1 ,6-dien-3-ol; 3,7-dimethylocta-1 ,6-dien-3-yl acetate; 3-hydroxy-2- methyl-4H-pyran-4-one; 4-methyl-4-sulfanylpentan-2-one; 2-(4-methylcyclohex-3-en-1 - yl)propane-2-thiol; mercapto-para-menthan-3-one; methyl acetate; methyl 2-aminobenzoate; 2-methyl-butanoic acid; methyl 3-phenylprop-2-enoate; methyl 3-oxo-2- pentylcyclopentaneacetate; 5-methylfuran-2-carbaldehyde; 7-methyl-3-methyleneocta-1 ,6- diene; (Z)-3,7-dimethylocta-2,6-dien-1 -yl acetate; 5-pentyloxolan-2-one; nonanal; 4,4a- dimethyl-6-(prop-1 -en-2-yl)-4,4a,5,6,7,8-hexahydronaphthalen-2(3H)-one; 5-butyloxolan-2- one; octanal; octanoic acid; 2,3-pentanedione; 3-methylbutyl acetate; 3-methylbutyl 3- methylbutanoate; propyl acetate; (2E,6E,9E)-2,6,10-trimethyldodeca-2,6,9,1 1 -tetraenal, ; (2E,6E)-2,6-dimethyl-10-methylidenedodeca-2,6,1 1 -trienal; 4-methyl-1 -propan-2-ylcyclohex- 3-en-1 -ol; 1 -methyl-4-propan-2-ylcyclohexa-1 ,3-diene; 2-(4-methyl-1 -cyclohex-3-enyl)propan- 2-ol; 1 -methyl-4-(propan-2-ylidene)cyclohex-1 -ene; 2-(4-methylcyclohex-3-en-1 -yl)propan-2-yl acetate; 4a,5-dimethyl-3-prop-1 -en-2-yl-2,3,4,5,6,7-hexahydro-1 H-naphthalene; 4-hydroxy-3- methoxybenzaldehyde; and mixture thereof.

Essential oils, fruit essences and flavour compositions are compositions comprising more than one flavour ingredient. Essential oils and fruit essences are obtained from nature, for instance by extraction or distillation, whereas flavour compositions are obtained by blending natural and/or artificial flavour ingredients.

Essential oils may include spearmint oil, cinnamon oil, oil of wintergreen (methyl salicylate), peppermint oil, Japanese mint oil, clove oil, bay oil, anise oil, eucalyptus oil, thyme oil, cedar leaf oil, oil of nutmeg, allspice, oil of sage, mace, oil of bitter almonds, and cassia oil; fruit oils including citrus oils, such as lemon oil, orange oil, lime oil, grapefruit oil, yuzu oil, and sudachi oil, and fruit essences from apple, pear, peach, grape, raspberry, blackberry, gooseberry, blueberry, strawberry, cherry, plum, prune, raisin, cola, guarana, neroli, pineapple, apricot, banana, melon, apricot, cherry, tropical fruit, mango, mangosteen, pomegranate, papaya, and so forth.

Exemplary flavour compositions include a milk flavour, a butter flavour, a cheese flavour, a cream flavour, and a yogurt flavour; a vanilla flavour; tea or coffee flavours, such as a green tea flavour, an oolong tea flavour, a tea flavour, a cocoa flavour, a chocolate flavour, and a coffee flavour; mint flavours, such as a peppermint flavour, a spearmint flavour, and a Japanese mint flavour; spicy flavours, such as an asafetida flavour, an ajowan flavour, an anise flavour, an angelica flavour, a fennel flavour, an allspice flavour, a cinnamon flavour, a chamomile flavour, a mustard flavour, a cardamom flavour, a caraway flavour, a cumin flavour, a clove flavour, a pepper flavour, a coriander flavour, a sassafras flavour, a savory flavour, a Zanthoxyli Fructus flavour, a perilla flavour, a juniper berry flavour, a ginger flavour, a star anise flavour, a horseradish flavour, a thyme flavour, a tarragon flavour, a dill flavour, a capsicum flavour, a nutmeg flavour, a basil flavour, a marjoram flavour, a rosemary flavour, a bayleaf flavour, and a wasabi (Japanese horseradish) flavour; a nut flavour such as an almond flavour, a hazelnut flavour, a macadamia nut flavour, a peanut flavour, a pecan flavour, a pistachio flavour, and a walnut flavour; alcoholic flavours, such as a wine flavour, a whisky flavour, a brandy flavour, a rum flavour, a gin flavour, and a liqueur flavour; floral flavours; and vegetable flavours, such as an onion flavour, a garlic flavour, a cabbage flavour, a carrot flavour, a celery flavour, mushroom flavour, and a tomato flavour.

In a further embodiment, the oil phase of the emulsion may also comprise a vegetable oil. Emulsions that contain vegetable oils have been found to be more easily processed and less sensitive to changes in the nature of the flavour ingredients, essential oils or flavour oils used.

In one embodiment, the level of vegetable oil in the oil phase is from about 5 to about 75 wt%, preferably from about 10 to about 50 wt%, for example 20 wt%, 25 wt%, 30 wt%, or 40 wt%, based on the total weight of the oil phase.

Suitable vegetable oils are well known to the person skilled in the art, and include, for example, sunflower oil, and fatty acid glycerol ester selected from the group consisting of monoacyl, diacyl and triacyl monoglycerides, also referred to as mono-, di- and triglycerides having fatty acid rests having an alkyl chain carbon number of from about 5 (e.g., hexanoic acid) to about 24.

In a particular embodiment, the fatty acid glycerol esters are medium chain triacyl

monoglycerides, also called medium chain triglycerides (MCT), having fatty acid alkyl chain carbon numbers of from 5 (hexanoic acid) to 1 1 (dodecanoic acid). Such medium chain triacyl monoglycerides are characterized by a distribution of analogues and isomers, characterized in such that each glycerol moiety may be bound to the same or different fatty acid moieties. For example, the medium chain triacyl monoglycerides may be a glycerol tri-octanoate, or a glycerol dioctanoate mono didecanoate, or a glycerol mono-hexanoate mono- octanoate mono-decanoate. Additionally, the proportion of these different species may vary from one commercial brand to the other. These medium chain triglycerides are available commercially under different trade names. For example, a MCT having 55 wt% octanoic acid rest and 45 wt% decanoic acid rest is available under the trade name CAPTEX 255, ex Abitec

Corporation; a MCT having 65 to 80 wt% octanoic acid rest and 20 to 35 wt% decanoic acid rest is available under the trade name MIGLYOL 810, ex Cremer; a MCT having 50 to 60 wt% octanoic acid rest and 30 to 45 wt% decanoic acid is available under the trade name MIGLYOL 812, ex Cremer, 65% to 75% octanoic acid rest and 25% to 35% wt% decanoic acid rest is available under the trade name MCT OIL, ex Melrose. In another embodiment, the oil phase may also comprise a weighting agent. Suitable weighting agents are well known to the person skilled in the art, and include, for example sucrose esters, such as sucrose acetate isobutyrate (SAIB), ester gums, darmmar gum or elemi gum. Oil-soluble flavour ingredients having a density higher than 1 may also be used.

In another embodiment, the water phase of the emulsion may comprise sugars and oligosaccharides, sugar alcohols, polyols, sweeteners, acidifiers, co-solvents, preservatives and/or antioxidants, colorants, viscosity modifiers and/or suspending agents, and mixtures thereof.

Suitable sugars and oligosaccharides are well known to the person skilled in the art, and include, for example, sucrose, fructose, glucose, trehalose, galactose, rhamnose, maltose, inverted sugar, rhamnose, ribose, and isomerized liquid sugars, such as high fructose corn/starch syrup, dextrins, soybean oligosaccharides, glucose syrup and mixtures thereof.

Suitable sugar alcohols are well known to the person skilled in the art, and include, for example mannitol, sorbitol, lactitol, xylitol, isomalt, and mixtures thereof.

Suitable polyols are well-known to the person skilled in the art and include, for example, glycerol, erythritol, and mixtures thereof.

Suitable sweeteners are well known to the person skilled in the art, and include but are not limited to aspartame, neotame, thaumatin, stevia or extracts thereof, sucralose, acesulfame potassium, saccharine, and mixtures thereof.

Suitable acidifiers are well known to the person skilled in the art, and include but are not limited to citric acid, adipic acid, tartaric acid, benzoic acid, lactic acid, and their salts, and phosphoric acid.

Suitable co-solvents are well known to the person skilled in the art, and include but are not limited to ethanol, isopropanol, and triacetin.

Suitable preservatives and antioxidants are well known to the person skilled in the art, and include but are not limited to tocopherol, ascorbic acid and some of the acidifiers mentioned hereinabove, such as lactic acid, benzoic acid, citric acid and their salts. Dipropylene glycol may be used as a preservative and co-solvent.

Suitable colorants are well known to the person skilled in the art, and include but are not limited to carotenes, polyphenols and anthocyanins.

Suitable viscosity modifiers and suspending agents are well known to the person skilled in the art, and include but are not limited to polysaccharide, such as gum acacia, xanthan gum, pectins, octenyl succinate-modified starch, cellulose gels, carboxymethyl cellulose, and cellulose gums.

The emulsion may also comprise food supplements, such as vitamins; oligo-elements, such as iron, cobalt, magnesium, fluor, and the like; flavonoids; amino acids; polyunsaturated fatty acids; and other nutraceutical ingredients.

Generally any flavour ingredients, food additives and food supplements, such as those described in“Chemicals Used in Food Processing”, Publication No 1274, pages 63-258, by the National Academy of Sciences, can be used. This publication is incorporated herein by reference.

In a particular embodiment there is provided an emulsion comprising an oil phase containing one or more flavour ingredients, dispersed in a water phase, wherein said emulsion comprises tea seed saponins.

Tea seed saponins are commercially available. Preferably, extracts from the seeds of Camellia oleifera (species) are used. The extracts may comprise at least 60 wt% of saponin, e.g from 90 - 98 wt% of saponin. The saponins present in the extract of Camellia oleifera seeds are predominantly monodesmosidic triterpenoids.

The level of tea seed saponins may vary from composition to composition, and a skilled person can readily determine an appropriate amount with only simple experimentation. The level of tea seed saponins required depends on the level of the oil phase in the emulsion. In an embodiment, the weight ratio of tea seed saponins to oil phase is at least 0.05 weight parts saponin per 1 weight part of the oil phase. For example, the weight ratio may be up to 0.4 : 1 , including from about 0.1 : 1 to about 0.35 : 1 , which includes a saponin : oil phase weight ratio from about 0.15 : 1 to about 0.3 : 1 , e.g. 0.2 : 1 or 0.15 : 1 . In general, although the best results are obtained with ratios inside the range, they should not be considered as absolute limits. If the weight ratio of the tea seed saponins and the oil phase is too high, excessive foam formation may occur during the preparation of the emulsion. On the other hand, if the weight ratio between the tea seed saponins and the oil phase is too low, this may lead to emulsions that are less stable with respect to Ostwald ripening.

In an embodiment, the level of the oil phase in the emulsion is from about 1 to about 50 wt%, more particularly from about 5 to about 30 wt%, still more particularly from about 8 to about 20 wt%, based on the total weight of the emulsion.

Preferably, the emulsion comprises sugars, and/or oligosaccharides and/or sugar alcohols; as well as polyols and/or co-solvents.

In one embodiment, the level of sugars, oligosaccharides and/or sugar alcohols in the emulsion is from 1 up to 60 wt%, preferably from 10 up to 40 wt% based on the total weight of the emulsion. They may be admixed to the water phase in neat, solid form or in the form of a syrup containing water. If a syrup is used, the effective level of sugar in the syrup is considered. The polyols, the co-solvent, and any other components that are soluble in water may be admixed to the water phase in neat form.

In one embodiment, the level of polyols in the emulsion is from about 1 to about 90 wt%, based on the total weight of the emulsion. In a particular embodiment, the polyol is glycerol.

In one embodiment, the level of co-solvents in the emulsion is up to about 25 wt%, more preferably less than about 20 wt%, more preferably less than 15 wt%, based on the total weight of the emulsion.

In another aspect there is provided a method of obtaining an emulsion comprising tea seed saponin, an oil phase and a water phase, wherein the oil phase is dispersed in the

waterphase in form of droplets, by performing the steps of: a) admixing tea seed saponin to the water phase and/or the oil phase; and b) blending the water phase with the oil phase under high shear,

and wherein said droplets have a Z-average diameter of 190 nm or smaller after 1 month storage at 40°C

In one embodiment the tea saponins are admixed with the oil phase. Dispersing the tea seed saponins into the oil phase prior to forming the emulsion has the advantage of decreasing foam formation during high shear blending.

Upon formation of an emulsion comprising one or more flavour ingredients, part of the flavour may partition between the oil phase and the water phase. This is especially true in the case of polar flavour ingredients being soluble or partially soluble in water. Alternatively, the water soluble flavour ingredients may directly be admixed to the water phase.

The applied shear must be sufficiently high to disperse the oil phase in the water phase in the form of droplets and to reduce said droplets to the desired size. This is achieved by means of high shear mechanical equipment based on the rotor-stator technology well known to the skilled person, such as a Polytron and Megatron (supplied by Kinematica) or Ultra-Turrax (supplied by IKA). Mechanical shear is applied, for example, for about 2 to 20 minutes at a revolution of about 5Ό00 - 30Ό00 rpm (which includes 15Ό00, 20Ό00 and 25Ό00 rpm).

Alternatively, the emulsion may be formed by means of high pressure homogenization, that is, the composition is homogenized with high pressure homogenization by passing said composition one or more times through a valve. In general the pressure applied is about 15 to 60 MPa (which includes a range from about 20 - 50, specific examples being 35 and 45 MPa). The number of times the composition passes through the valve may be 1 to 10 times, (such as 2 - 5 times, e.g. 3 or 4 times). If a two-stage homogenization valve is used, the composition is passed through two valves, wherein the counter pressure exerted by the second valve is set to about 5-50 % (e.g. 10 - 20, including 15%) of the pressure drop induced by the first valve. The emulsion is homogenized for 1 -10 passes through the two valves (which includes 2 - 5, e.g. 3 or 4 passes). Optionally, a cooling step may be applied in between passes, in particular when the temperature of the emulsion exceeds 40 °C, which otherwise may lead to changes in the flavour profile, should temperature sensitive flavours be used. The combination of rotor-stator and high pressure technologies is also possible.

The emulsion obtained as described hereinabove may be converted to a solid form by the means of methods known to the art, and then further be diluted in water. The emulsion may, for example, be spray-dried in a conventional spray dryer or a multi-stage spray drier by adding appropriate filler materials known to the persons skilled in the art and using any spraying device known to the art, such as an atomizer, a one-fluid nozzle or a two-fluid nozzle, in order to form a powder with a particle volume average diameter of from about 10 to about 100 micrometers (about 200 micrometers if a multistage spray dryer is used).

Alternatively, the emulsion may be sprayed onto a carrier material such as a crystalline or granulated sugar by means of a spray coating, granulation or agglomeration process, for example in a fluidized bed, in order to form a granulate form with volume (or number) average diameter of from about 200 to 500 micrometers or more.

Alternatively, the emulsion obtained as defined above may directly be diluted in water, or admixed with a fruit juice or a fruit juice concentrate, which can be further diluted with water, in order to provide the final beverage product ready for consumption.

In one particular embodiment the emulsion is diluted by a factor of from about 1 /10000 to about 1 /10, particularly from about 5/10000 to about 5/100, and more particularly from about 1/1000 to about 2/100 in the final beverage product ready for consumption.

In one embodiment the flavoured beverage may be carbonated.

In one particular embodiment solidified emulsion is diluted by a factor of from about 5/10000 to about 2/10, more particularly from about 1 /1000 to about 1 /10, still more particularly from about 2/1000 to about 4/100 in the final beverage ready for consumption.

The disclosure is further exemplified with reference to the following non-limiting examples.

Example 1 : Flavour emulsions

This example discloses the preparation of flavour emulsions according to the present invention. The compositions of the emulsions obtained are reported in Table 1 below. In the formulations #1 and #2 (details see Table 1 ), an aqueous solution of tea seed saponin and water was prepared. In a second vessel, citric acid, propylene glycol, glycerin, and sugar syrup were mixed and stirred until a homogeneous mixture was obtained. To the water phase thus obtained, the aqueous tea seed saponin solution was added under stirring at low shear, in order to avoid foaming. A flavour oil (lemon lime oil) was mixed with vegetable oil (MCT oil) and then added under high shear at 18Ό00 rpm to the water phase. High shear blending was continued for 5 minutes. The resulting coarse emulsion was high pressure homogenized with a two-stage homogenizing value assembly with a first homogenization valve operating at 40 MPa and the second homogenization valve operating at 5 MPa. The homogenized emulsion was passed several times through the high pressure homogenizer. After each pass an emulsion sample was taken for the determination of the droplet diameter. Homogenization was stopped once a target diameter had been achieved. In the formulation #3, the same experimental conditions were applied, but the tea saponins were first dispersed in the oil phase, instead of being dissolved in water.

Table 1 :

(1 ) supplied by Geneham Pharmaceutical Co. LTD and used as received

(2) Sucrose syrup (brix 65) containing 35 wt% water

(3) Captex® 355, supplied by Abitex Example 2: Z-averaae oil droplet diameter and turbidity

a) Z-average oil droplet diameter [nm]

The emulsion stability was assessed by measuring the Z-average oil droplet diameter of the emulsions before and after storage at 40 °C. The emulsions were diluted 1000 times with micro-filtered and degassed deionized water and immediately transferred to a Dynamic Laser Light Scattering measurement device, Malvern Zetasizer Nano ZS90. The Z-average oil droplet diameter was then calculated using the software implemented in the measurement device. The results are reported in Table 2.

Except for formulation #1 , where the droplet diameter increased during storage, the Z- average oil droplet diameter remains nearly constant or even decreases during storage @ 40°C. The Z-average oil droplet diameter remains below 190 nm after storage in all cases. The results confirm the excellent stability of emulsions comprising tea seed saponins. b) Turbidity [NTU]

The turbidity was measured in diluted emulsions. 0.33 g of each one of the emulsions prepared according to Example 1 were added to 1 kg of deionized water and transferred to a 95 mm x 25 mm borosilicate glass photometric cell and the turbidity was determined by measuring the light scattering intensity at a wavelength of 870 ± 30 nm and an angle of 90° (forward scattering). The turbidimeter was a Hach 2100N Laboratory Turbidimeter. It was calibrated using Formazin standard suspensions and the results are given in Nephelometric Turbidity Units (NTU, Table 2). Table 2:

As apparent from Table 2, emulsions obtained by using tea seed saponins as sole emulsifier have the desired Z-average droplet diameter for providing transparent beverages. Furthermore the emulsions obtained are stable during storage @ 40°C over a prolonged period of time.

Claims

1 . A stable emulsion comprising a tea seed saponin, an oil phase and a water phase, wherein the oil phase is dispersed in the water phase in form of droplets,

characterised in that the Z-average diameter of said droplets after 1 month storage at 40 °C is 190 nm or smaller.

2. The emulsion according to claim 1 comprising one or more flavour ingredients.

3. The emulsion according to claim 2 wherein the one or more flavour ingredients are present in the oil phase.

4. The emulsion according to any of the preceding claims wherein the oil phase contains vegetable oil.

5. The emulsion according to any one of claims 1 through 4, wherein the emulsion

comprises tea seed saponins and the oil phase in a weight ratio from 0.05 : 1 to 0.4 :

1 (tea seed saponin : oil phase).

6. The emulsion according to any of the preceding claims further comprising one or more polyol and/or one or more acidifier, or mixture thereof.

7. A method to obtain an emulsion comprising tea seed saponin, an oil phase and a water phase, wherein the oil phase is dispersed in the water phase in form of droplets, by performing the steps of:

a. admixing tea seed saponins to the water phase and/or to the oil phase, and b. blending the water phase with the oil phase under high shear,

and wherein said droplets have a Z-average diameter of 190 nnm or smaller after 1 month storage at 40°C.

8. The method according to claim 7, wherein the oil phase contains vegetable oil and one or more flavour ingredients.

9. The method according to claim 8, wherein the tea seed saponin is admixed to the oil phase.

10. A method according to claim 8 or claim 9further comprising the step of spray-drying the emulsion.

1 1 . A method according to claim 10 wherein the emulsion is sprayed onto a carrier material.

12. A beverage comprising the stable emulsion as defined in any of the claims 1 through 6.

13. The use of the emulsion as defined in any of the claims 1 through 6 for generating a beverage having a turbidity of 20 NTU or less.