The ability to separate one component of a mixture from other components of the mixture relies on a difference between the properties of the components to be separated. For example, a difference in physical or chemical properties such as molecular weight, hydrophobicity, volatility, charge or binding constants (for binding to a ligand or substrate) can be exploited to allow a compound to be separated from its mixtures with other compounds.

Current separation techniques which exploit the differences in chemical or physical properties of compounds include evaporation (eg, distillation), membrane processes such as pervaporation, or processes based on size selective permeation (eg, dialysis), chemical or biological complexation, immobilisation (eg, onto ion-exchange resins), extraction into solvents of different polarity and membrane-mediated extraction.

The extraction of materials from natural tea products to obtain tea extracts having the taste and/or aroma of the natural tea products has previously been carried out. However, the extraction processes can be relatively complex and often fail to separate the desired components from those which are not desired. For example, when extracts are prepared from tea leaf material (generally as an aqueous infusion), they are often undesirably coloured, can be poor in aroma and/or taste, may be particularly lacking in

top notes especially when thermal processing steps have been used and may contain solids which are insoluble in water.

As described in GB 2 173 985, milled dry black tea may be extracted using a liquid mixture of carbon dioxide and ethanol to provide an alcoholic solution comprising tea extract.

It is well known that aqueous extracts obtained from tea contain a number of solids, some of which are soluble in hot water but not cold water. The components that are insoluble in cold water are often referred to as "tannins"or"tea creams". These insoluble components cause undesirable haziness or cloudiness in beverages, which is unacceptable to the consumer.

A common approach to solving this problem in the art has been to solubilise the"tannins"or"tea creams".

Thus, US 5, 827,560 describes a process for producing a tea extract with good colour (ie, that of a natural tea beverage) which contains solubilised tannins. The process comprises extraction of tea solids from tea leaves using water. The insoluble tannins are separated and oxidised under raised temperature conditions. No acidifying or basifying agents are used.

A process in which a hot water extract of black tea leaves is concentrated, cooled and treated with catechins is described in US 4,680,193. The catechins substantially solubilise"tea creams"to produce a cold water soluble tea extract.

US 4,156,024 describes a process for producing a soluble tea product comprising hot water extraction of fermented black tea, followed by cooling and separate catalytic oxidation of precipitated tea tannins. The oxidation of

dispersed tannins in water requires oxygen in the presence of an inorganic oxidation catalyst at a specified pH.

US 3,950,553 describes a process for preparing a powdered tea extract which is soluble in cold water. The process comprises a hot water extraction of tea leaves followed by cooling and separate oxidation of precipitated tannin at a specified temperature and pH. Non-oxidised tanin is then contacted with oxidised tannin in order to decolourise the oxidised tannin.

GB 1,055,550 describes a process for obtaining a tea extract by a combination of percolator and slurry extraction techniques. In order to produce cold water soluble tea extracts, the tea tannins are precipitated, separated, oxidised then returned to the mother liquor.

GB 1,043,792 describes a process for clarifying tea brew and removing astringent tannins by adding a minute quantity of a water soluble polyvinylpyrrolidone, followed by filtration.

None of the above-mentioned documents describes a tea extract which is substantially colourless in solution and which can be prepared as a white or colourless solid The present invention aims to provide tea extracts having improved flavour and/or aroma properties compared to tea extracts produced by other extraction methods and to alleviate one or more of the problems mentioned above.

The present invention also seeks to provide a process for providing tea extracts from a mixture in the aqueous phase, which can be carried out relatively simply and in a good yield.

According to the present invention, there is provided a tea extract which comprises compounds responsible for the aroma and/or taste of tea, wherein the extract is soluble in water at room temperature and contains less than 30% by weight tannins based on the dry weight of the tea extract.

In another aspect, the invention provides a method of producing a tea extract which comprises separating an aqueous phase comprising a mixture of tea extract and one or more further components from a water immiscible hydrophobic phase by means of a hydrophilic membrane and allowing said tea extract to move out of the aqueous phase through the membrane and into the water immiscible hydrophobic phase.

The tea extract of the present invention comprises compounds responsible for the aroma and/or taste of tea. Such compounds may include, for example, linalool, geraniol and other compounds which are the principal flavour components of conventional teas. The extract is soluble in water at room temperature and contains less than 30% (preferably less than 10%, more preferably less than 5%) tannins based on the dry weight of the tea extract, as determined by the method described herein. Reducing the amount of tannins in the extract reduces the bitter taste of the extract and the colour of, and degree of insoluble material in, the extract.

The tea extract may be produced from material obtained from tea plants, preferably from leaf material. The leaf material may be in whole or comminuted form (preferably comminuted) and may be dried. Thus, the tea

extract can be obtained from commercially available loose-leaf tea, suitable for infusion to produce a tea drink. The leaf material may have been processed to any extent (suitable material includes Oolong tea, for example).

The tea from which the extract is produced can be any variety of tea. For example, Lapsang Souchong, Ceylon, Darjeeling, English breakfast, Kenyan, Mate, Rooibos and Green teas all produce acceptable tea extracts according to the invention.

The tea extract may be obtained at, above or below the"creaming point"of the tea (typically about 42°C).

The tea extract of the invention preferably dissolves in water to give no detectable residual solids. By the term"no detectable residual solids"we mean that no solids can be observed visually when the tea extract is dissolved in water to give a concentration at about the level normally found in a conventional tea drink.

The tea extract is preferably a pale coloured (or white) solid which gives a substantially colourless solution when dissolved in water. By"substantially colourless"we mean that the solution would have no detectable colour when observed visually when the tea extract is dissolved in water at a concentration sufficient to give a taste similar to that of a conventional tea drink. Preferably, the tea extract has an absorbance of less than 1 x 104 at 570 nm when dissolved in water at a concentration of about 11.9 mg/ml.

The tea extract is also very soluble in ethanol, making it suitable for use in alcoholic beverages and ethanol based fragrances.

The tea extract may be used alone in order to provide the aroma and/or taste of tea. Alternatively, the tea extract can contain preservatives and/or stabilisers or can be used in conjunction with a carrier.

The tea extract of the present invention is obtainable by a method comprising separating an aqueous phase comprising a mixture of tea extract and one or more further components from a water-immiscible hydrophobic phase by means of a hydrophilic membrane and allowing said tea extract to move out of the aqueous phase through the membrane and into the water immiscible hydrophobic phase.

Preferably the tea extract is more soluble in the aqueous phase, for example water, than in the water-immiscible hydrophobic phase but still has some solubility in the water-immiscible hydrophobic phase. More preferably, the components of the tea extract have a water solubility of greater than about 0.010 gel-', although other solubilities are possible. Preferably, the said further components have a water solubility of less than 0.010 gl-l, although other solubilities are possible. Preferably the tea extract has a solubility of at least 0.1 gel-', more preferably at least 1.0 gel-', even more preferably at least 5.0 gel-'. Solubilities are based on deionised water at 25°C.

Preferably, the said further components are either more hydrophobic than the components of the tea extract, such that they cannot pass across the hydrophilic membrane, or are more hydrophilic than the components of the tea extract, so that although they can pass across the hydrophilic membrane they cannot dissolve in the water-immiscible hydrophobic phase.

The method of the invention relies on the selective movement of the tea extract from the aqueous phase across the hydrophilic membrane into a

second water immiscible hydrophobic phase. The tea extract is able to dissolve and pass through a hydrophilic membrane and is soluble in a water- immiscible hydrophobic phase.

In the invention the tea extract is typically more soluble in water than in the hydrophobic phase (for example, a water-immiscible organic solvent) so as to be able to pass across the hydrophilic membrane but also has some solubility in the water-immiscible hydrophobic phase, so that it can accumulate in the water-immiscible hydrophobic phase. Also, preferably the organic solvent, where this is the hydrophobic phase, does not pass across the hydrophilic membrane, so those molecules with a more hydrophobic character than the tea extract present in the aqueous phase cannot be extracted across the membrane and into the water-immiscible hydrophobic phase.

Hence, without wishing to be bound by theory it is believed that according to the method of the present invention, separation of the tea extract from the further components will be achieved because any molecules that are more hydrophobic than the tea extract will not pass through the hydrophilic membrane, and any molecules that are more hydrophilic than the tea extract will not dissolve into the hydrophobic phase even though they can readily pass through the hydrophilic membrane.

By using the system of the invention with a hydrophilic membrane and a water-immiscible hydrophobic phase, further component (s) which are more hydrophilic than the tea extract, so that they can pass through the hydrophilic membrane, cannot dissolve into the hydrophobic phase.

The aqueous phase containing the tea extract typically comprises water, the tea extract and one or more further components. The aqueous phase may contain other solutes or water miscible solvents that may assist in the separation process. Each of the components of the mixture may be present in the aqueous phase in solution, in the solid phase or in a separate liquid phase, such as in the form of particles or droplets suspended or dispersed in the aqueous phase.

The mixture from which the tea extract is extracted in the method of the invention may contain the tea extract in relatively small amounts up to relatively large amounts (eg, 1 % to 99% by weight).

The tea extract may contain a single component or two or more components. Where tea extract contains two or more components, they may be separated from each other by repeating the method of the invention using a different membrane and/or different aqueous and/or hydrophobic phases or by employing conventional separation techniques.

The aqueous phase may comprise a suspension, dispersion or solution of a natural tea product or an extract thereof, or waste material such as spent tea.

For example, the aqueous phase may be an infusion obtained by treatment of the natural tea product with hot water. The natural tea product or extract may be obtained directly from the naturally occurring source of the natural tea product, for example by treatment with hot water, or may be obtained following a pretreatment of the naturally occurring source of the natural tea product to assist in the release of the natural tea product eg, by treatment of the naturally occurring source with an enzyme. For example, in the production of a tea extract, the tea leaf material may be treated with a glycosidase prior to treatment with hot water.

In a preferred embodiment of the method, the tea extract comprises compounds responsible for the aroma and/or the taste of tea and the aqueous phase comprises an infusion of tea leaves.

Preferably, the aqueous phase comprises an extract obtained by heating tea leaves in water at a temperature of about 90°C up to the boiling point of the solution.

The tea extract of the invention has surprisingly been found to have a very good quality aroma and/or taste, a lighter colour, and much less propensity to form haze and/or precipitates on storage and/or cooling, than tea extracts produced by conventional methods.

The membrane which is used in the method of the invention is hydrophilic.

The selection of a suitable membrane for any particular extraction can be readily made by the skilled person. Suitable membranes include, for example, hydrophilic polymers such as acrylic co-polymers, modified polyether sulphones, polysulphones and cellulose or other modified or unmodified cellulosic polymers, eg, cellulose acetate membranes.

Other suitable membranes may be in the form of hollow fibres. Hollow fibre membranes are particularly useful when the method of the invention is performed on a larger scale. They have the advantage of providing a large area (m2) of membrane surface per area (m2) of floor space occupied.

Suitable hollow fibre membranes include polysulphone membrane and polyacrylonitrile membrane. The properties of preferred hollow fibre membranes are shown in the table below. Module MWCO Water Area Fibre Module Module Max2 Inlet Max2 Type dalton Flux (m2/ft2) Bore Length outside Pressure #P (l/hr) (mm) (mm/in) diameter (bar/psi) (bar/psi) (mm/in) P0olyacrylonitrile ACP-0053 13,000 2.2 0.012/0.13 1.4 130/5.1 20/0.8 1/15 1/15 Polysulphones SLP-0053 10,000 5.7 0.015/0.16 1.4 130/5.1 20/0L8 1/15 1/15 SEP-0013 3,000 2.5 0.017/0.18 0.8 130/5.1 20/0.8 1/15 1/15 MWCO = molecular weight cut off.<BR> these hollow fibre membranes are supplied by Pall Ulttrafine Filtration Co. (Pall Corp) of New York. All of the moidule<BR> components meet the requirements for biological test slisted in the United States Pharmacopoeia for Class VI Plastics at<BR> 121°C and are also constructed from materials listed in Title 21 of the US Code of Federal Regulations. The mateirals are<BR> resistant to a wide range of chemical agents and tolerate the pH range 1-14.

The hydrophobic phase can take a number of different forms.

In one embodiment of the method of the invention, the hydrophobic phase is a solvent which is immiscible with water. Solvents which may be used as a hydrophobic phase include, for example, branched and unbranched alkanes. Preferably, the alkanes are liquid at room temperature. Preferably the hydrophobic phase is hexane or comprises hexane. Suitable alkanes include Cg-Cio straight chain alkanes eg, n-hexane and n-decane. The hydrophobic phase may comprise a single solvent or a mixture of different solvents. Where the solvent comprises a mixture of different solvents, these are preferably miscible. During the method of the invention, the tea extract passes into the hydrophobic phase and will typically form a solution with the solvent. The tea extract can be isolated from the hydrophobic solvent by conventional techniques, including, for example, removal of the solvent by evaporation at elevated temperature and/or reduced pressure to leave behind the tea extract.

It is typically preferred not to use a solvent such as chloroform in which water is soluble, or which dissolves to some extent in water, in the method of the invention. Without wishing to be bound by theory, it is believed that the preferred solvents, such as the alkanes mentioned above, cannot pass through the hydrophilic membrane and dissolve the relatively hydrophobic molecules of the further components present in the aqueous phase. This inhibits the relatively hydrophobic molecules of the further components in the aqueous phase from being transported across the hydrophilic membrane into the hydrophobic phase.

Preferably, the hydrophobic phase includes alkanes which are liquid under the conditions of extraction and preferably alkanes which are liquid at room temperature, more preferably n-hexane.

The method of the invention may be carried out in any suitable apparatus in which the aqueous phase can be separated from the hydrophobic phase by a membrane. Preferably, the aqueous phase and/or the hydrophobic phase are moved relative to the membrane (eg, by stirring or other methods of causing circulation in liquids). Apparatus suitable for use in the method will be well-known to those skilled in the art. One illustrative form of apparatus in which the method of the invention may be carried out comprises the membrane in the form of a tube which contains the hydrophobic phase. The tube is at least partly immersed in the aqueous phase. The hydrophobic solvent may be substantially static in the tube, in which case the tube may be open at one or both ends or sealed at both ends. Alternatively, the hydrophobic liquid may flow along the tube, and the tube may pass into and out of the aqueous phase, to effect continuous extraction of the tea extract from the aqueous phase or the separation may employ a flat membrane with either cross-flow or tangential separator configurations.

The tea extract may be formulated together ; typically in a"ready to use" form, with a carrier material, as described hereinafter. This formulation of the tea extract with a carrier material may form part of the method of the invention rather than being a separate step after the tea extract has been produced according to the method of the invention. For example, if the carrier material is an absorbent substrate such as paper, it may be added to the solution of the tea extract which has passed through the membrane, before the solvent is evaporated. Alternatively, if the absorbant is, for example a maltodextrin it may be added in the same way. The absorbed

flavour can then be obtained in an easy to use form, for example by addition to a blend or by tableting.

In another aspect, the invention comprises a tea extract of the invention together with a carrier.

The carrier may comprise tea leaf material. Thus, the tea extract of the invention may be used to modify or to increase the flavour and/or aroma provided by tea leaf material. Preferably, the tea extract is used in an amount of less than 5% (more preferably less than 1%) by weight based on the weight of the tea leaf material.

Alternatively, the carrier may be a conventional tea extract. By the term "conventional tea extract"we mean a tea extract obtained by conventional methods which are known in the art.

The carrier may comprise paper, in which case the tea extract may be absorbed into and/or onto the paper. The paper may be paper which is suitable for use in making tea bags, in order to allow the extract of the invention to be delivered at the same time as a tea drink is made from tea leaf material contained in a tea bag. Alternatively, the paper may be suitable for use as packaging (eg, cardboard or paperboard). Impregnating the inside of a package for a conventional tea product with the tea extract of the invention allows the consumer to experience a greater aroma of the tea when opening the packaged tea product.

The carrier for the tea extract may be a liquid, such as glycerol. Liquid carriers allow the product to be used in a variety of food and/or beverage applications. Furthermore, formulating a product (such as a tea product) in

liquid form allows it to be dispensed by a variety of different routes, such as, for example, from a spray dispenser.

Carriers include carbohydrates, preferably mono-, di-or poly-saccharides, which are preferably water soluble. Suitable carriers of this type include maltodextrin, sorbitol, glucose, sucrose and mixtures thereof. The tea extract may be encapsulated in a matrix of these carriers, thus preventing the compounds responsible for the taste and/or aroma of the tea extract from being lost by evaporation before it is used. The product may therefore be in the form of a glass comprising a matrix of the carrier with the tea extract encapsulated in the matrix. This form of the product is preferably in the form of a powder or another solid body such as a tablet.

Tablets of the invention may be in a form suitable for easy use and dispensation (eg, by having a size of less than 1cm, such as from 2mm to 8 mm). The tablets may comprise two or more tea extracts, in which case one or more of the extracts may be produced by the method of the invention with, optionally, any remaining tea extracts produced in other ways. The tablets may comprise other materials such as, for example, acidulants (eg, lemon juice), colours, caffeine, flavours (eg, vanillin, citrus or mint flavours), whitener, sweeteners, thickeners, emulsifiers,"fizzing"agents such as sodium bicarbonate, vitamins, antioxidants (eg, ascorbic acid), preservatives and mixtures thereof. The tablets may be wrapped or coated, preferably with edible materials (eg, rice paper, edible foil or gelatin).

Preferably, the tablets are in unit dosage form. For example, in the case of a tablet for addition to hot or cold water to form a beverage, one tablet preferably provides a drink of standard size (eg, one cup or glass).

Examples of tablets provided by the invention include tea extract tablets such as green tea tablets.

The tablets of the invention may contain some of the retentate from the method of the invention (ie, the material which does not pass through the hydrophilic membrane). Preferably, the amount of the retentate by weight does not exceed the amount of extract by weight by a factor of more than 10.

Generally, it is the tea extract which is the useful material obtained from the method of the invention. However, the components which do not pass through the membrane in the method of the invention (ie, the retained components) may be useful in their own right. The retained components may be termed the"retentate". For example, tea retentate has been found to have useful properties.

The invention is illustrated, by way of example only, by reference to the accompanying drawing wherein: Figure 1 is a schematic diagram of an apparatus suitable for use in the invention.

Figure 2 is a schematic diagram of an apparatus suitable for use in tea extraction according to the invention.

In Figure 1, membrane 1 is in the form of a sealed tube and contains a hydrophobic solvent 2. Membrane 1 is of a hydrophilic membrane (such as of cellulose) and is disposed within aqueous phase 3 in container 4 containing the tea extract. The tea extract is typically present in aqueous

phase 3 together with other components. Membrane 1 remains sealed as aqueous phase 3 is stirred by stirrer 5. The tea extract which it is desired to extract from the aqueous phase 3 passes though membrane 1 and into solvent 2.

After the required degree of extraction has taken place, the solvent 2 can be recovered from membrane 1, for example by unsealing membrane 1 or cutting it open. The solvent 2 may then be removed, for example by evaporation under reduced pressure, to give the tea extract, as concentrated or solid products.

In Figure 2, tea is brewed in tea vessel (6). This is then pumped through hollow fibre cartridge (8) using pump (9), with recirculation back into the tea vessel (6). Simultaneously, n-hexane, held in hexane vessel (11), is pumped using pump (10) through the hollow fibre cartridge (8), with recirculation back into the hexane vessel (11). Both the pumps (9) and (10) have drains, and both recirculation lines have vents, ( (7) for the tea, and (13) for the hexane line). In addition, the hexane vessel (11) has an atmospheric vent (12). In addition pressures and flow rates are monitored at indicators (14), (15), (16) and (17) and controlled to ensure safe operation and the required residence times. Hollow fibre cartridge (8) is operated with the brewed tea passing through the hollow fibres (the lumen) and the hexane passing around the hollow fibres. A single hollow fibre cartridge may be used, as shown in Figure 2, or a plurality of cartridges, in series or in parallel, may be employed. When the required extraction period has been completed, the contents of the hexane vessel (11) are concentrated and dried to give the tea extract. The contents of the tea vessel (6) comprise the "retentate", which can be used as such, or concentrated and dried to give dried retentate.

The following non-limiting examples illustrate the present invention. Throughout the following examples, unless otherwise stated, the term "membrane"refers to a cellulose acetate membrane. The cellulose acetate membranes used typically had a molecular weight cut off of about 12,000 daltons. In the examples and throughout the specification, all percentages are percentages by weight unless indicated otherwise.

EXAMPLES Examples 1 to 3-Separation of tea extracts EXAMPLE 1 Tea Extraction 625ml deionised water in 2 litre conical flask was brought to the boil using a standard heating mantle. The flask was removed from the heat and 75g of loose leaf black tea were added. The flask was then brought back to the boil, removed from the heat again, and finally allowed to stand for a further 10 minutes. The contents of the flask were then filtered through muslin to yield a separated hot liquid tea infusion and retained tea leaves. The tea leaves were allowed to cool, then squeezed using a garlic press, and the resultant liquid extract combined with the initial tea infusion. The total volume of recovered tea infusion was approximately 500ml : this was then made back up to 625ml by the addition of a suitable volume of cold distilled water.

Dialysis tubing (cellulose acetate; thickness 0. 05mm, MW cut off 12-14000 Da) pre-soaked in deionised water containing 200ml n-hexane was added to the 625ml liquid tea infusion in a 2 litre conical flask. The flask was placed in an orbital incubator (200rpm, 30°C). After mixing for 21 hours, the dialysis tubing was removed and carefully dried with paper towelling. The n-hexane contents of the dialysis tubing were recovered and the solvent then removed by rotary evaporation to yield a residue (approximately 5mg of yellow/pale green extracted solids).

EXAMPLE 2 Rooibos Tea extract 75 g of Rooibos tea was emptied from tea bags. 625 ml boiling distilled water was poured onto the tea and the mixture was stirred. The tea was left to brew for 10 minutes before filtering through a mesh bag. The leaves were pressed and the liquor was strained through tights and then made back up to 625 ml with distilled water. A length of cellulose acetate dialysis tubing was wetted and knotted at one end. 200 ml hexane was transferred to the dialysis tubing and air was expelled before knotting the end. The dialysis tubing containing hexane was transferred to a 21 conical flask containing the 625 ml of rooibos tea. The flask was shaken at 200 rpm at 30°C for 20 hours. The hexane was recovered, evaporated off and taken to dryness under a stream of helium. A few mg of pale yellow solid with a distinctive rooibos aroma were obtained. EXAMPLE 3 Tea Extract

This example illustrates the use of a hollow fibre membrane.

A polyacrylonitrile hollow fibre cartridge ACP-0053 (supplied by Pall Ultrafine Filtration Co Pall Corp of New York) was engineered into a rig together with pumps, flow meters and pressure gauges etc. The cartridge was washed with NaOH solution, then with deionised water until a pH of 6.5 was reached, and then bubble tested to check integrity.

Extraction was carried out using tea prepared from 150g black leaf tea in 1250ml of water pumped at 200L/h with a back pressure of 13.8 KN/m2 (2psi) and 1,000 ml of hexane pumped at 42L/h at a back pressure of 34.5- 41.4 KN/m2 (5-6psi). Extraction was carried out continuously over 5 hours with the temperature of the tea reducing from 45°C to 20°C over the run, and with the pH of the tea remaining at pH4.9 throughout the extraction.

Subsequently, the hollow fibre cartridge was washed twice with 200ml aliquots of hexane. The hexane was recovered (1370ml) and evaporated to dryness at 40°C, reducing to 30°C at a pressure of-80KN/m2 (-0.8 bar) to yield 14.6mg of flavour solids.

EXAMPLE 4 Characterisation of Tea Extracts Methods 1. Sample preparation

50g of tea were added to 420 ml boiling water. This was stirred, brought back to boiling then removed from the heat and stewed for 10 minutes. Tea was then filtered through a mesh bag and tights, pressed and the liquor made up to 420 ml with cold distilled water. This process was repeated for PG Tips (trademark) loose leaf tea, Green Tea and Lapsang Souchong.

20 ml of each tea was removed for analysis of brewed tea. 400 ml tea was extracted according to Example 1 ; 130 ml hexane was transferred to dialysis tubing and placed in the tea. This was extracted for 20 hours at 30°C/200 rpm. Hexane was removed by evaporation and blowing with helium to obtain a solid sample of tea extract. 20 ml of the retentate were retained for analysis. The tea extracts obtained in this way were: Tea Leaf mg of extract/lOOg dry weight tea leaf Loose leaf 4.6 Lapsang Souchong 43.2 Green Tea 8. 2 2. Tannin Assay Reagents: folin denis reagent (Riedel-de Haen) Saturated Na2C03 solution: 35g Na2C5) 3 dissolved by heating to 70-80°C.

Cool to room temperature. Tannic acid standard solution: 0.1 mg/ml.

Procedure A standard curve was prepared by substituting 1 ml of sample 0,1,2,3, or 5ml tannic acid standard at 0.1 mg/ml in the following procedure:

50 ml volumetric flasks were half-filled with distilled water. 1 ml sample was added (brewed teas retentates were used at 1/10 dilution; tea extracts were dissolved in 5 ml cold water and used neat). 2.5 ml folin denis reagent was added followed by 5 ml Na2C03 solution. Samples were made up to 50ml and mixed well by inversion. After 30 minutes, the absorbance was read at 760 nm. Absorbencies of samples were compared to a standard curve, prepared alongside samples.

The tannin content of original tea leafs, retentates and extracts obtained in this way were: Tea Mg Mg Tannin % of total Mg tannin/g tannin/dry content tannin tannin/g dry solids tea (% by extracted of dried weight tea extract weight) retentate leaf Loose leaf 67.0 29.5 2.95 0.002 66.0 Lapsang 39.0 200.0 20.0 0.22 37.0 Souchong Green Tea 54.0 4.4 0.44 0.0007 50.0 3. Tea Precipitate Measurement 10 ml of each brewed tea and retentate tea samples were transferred to nalgene centrifuge tubes of known weight. Tea samples were centrifuged for 20 minutes at 4000 rpm. The supernatant was discarded and the pellets were dried in an oven at 40°C. When dry the centrifuge tubes containing tea pellets were weighed and mg precipitate/l Oml was recorded.

1 ml of each sample of tea extract according to the invention was transferred to a weighed eppendorf tube. Tea extract samples were centrifuged for 20 minutes at 4000 rpm on the biofuge. No visible pellets were observed so a further spin of 5 minutes at 13,000 rpm was performed. The supernatant was discarded and any pellets were dried and weighed as above.

The weight of tannin precipitate in the tea samples obtained in this way were: Mg tanning Mg tannin/g % of total Mg tannin/g dry weight dry solids precipitate of dried tea leaf tea extract extracted retentate Loose leaf 34.6 0.0 0 37.0 Lapsang 28.3 69.4 0.15 37.0 Souchong Green Tea 22.9 0.0 0 27.6 Therefore the following can be concluded for loose leaf tea: Tea was brewed using 50g of loose leaf tea leaf.

This loose leaf brewed tea contains 3350 mg of tannins, that is 67 mg of tannin/g dry weight of tea leaf used.

Processing of this brewed loose tea according to the invention gave a permeate which when dried, yielded 2.3 mg of solid with a tannin content of 29.5 mg tannin/g dry solid of extract. That is the tannins comprise 2.95% of the dry solid, and represent only 0.069% of that present in the original tea.

The retentate remaining after the process of the invention contained 66 mg tannin/g of dried retentate, ie tannins comprised 6.6% of the

dry solid, and (assuming no losses) have 98.5% of the tannins present in the original tea.

Upon cooling, fresh brewed loose leaf tea was seen to produce 34.6 mg precipitate/g dry tea leaf and the retentate 37 mg precipitate/dry tea leaf. At 4 g/l, the loose tea extract contained no measurable precipitate.

See following tables that also contain the data for the Lapsong Souchon and Green tea.

4. Method for determining colour of extracts Note: LS-Lapsang Souchong GN-Green Tea PG-PG Tips (trade mark) tea Tea extracts produced according to the sample preparation set out above had been kept at 4°C for 3 days.

These samples were centrifuged at 13,000 rpm/5 min to remove any precipitate-obtained clear solutions for the spectra work. Quartz curvettes (lml) were used and the range 800 nm to 200 nm was investigated.

Preliminary scans revealed that peaks were seen at 270 nm and 373 nm. In addition, the absorbance of teas at 570 nm is used as a means of characterising the tea, and so this wavelength was also investigated.

3 teas were investigated (LS, GN and PG) and 3 fractions were obtained from each tea (whole tea, spent tea (ie, the remaining tea after it has been

subjected to extraction according to the invention), extract according to the invention).

To obtain absorbances at 570 nm and 373 nm required a ten fold dilution of the samples (all dilutions in H20). To obtain the absorbance at 270 nm, a 1000 fold dilution was required (but only ten fold for tea extracts according to the invention). After obtaining all of the absorbance values, these were recalculated to give the absorbance of neat samples at either 373 nm or 270 nm. This allowed the 270/373-absorbance ratio to be determined (see tea characterisation table). It was felt that the low absorbance values of tea extracts of the invention at 570 nm would make any use of them as ratios unreliable, and therefore these were expressed as stand-alone values. However, to have some form of comparison between tea fractions, the absorbance at 570 nm was determined for a cup of tea equivalent (ie the weight of tea or tea extracts per ml H20 required to give a"cup of tea"was estimated and the absorbances adjusted accordingly).

The results are summarised in the tea characterisation tables, along with the tannin and precipitate data.

Characterisation of Tea, Spent Tea versus 'Tea' Extracts of the Invention<BR> Lapsong Souchong % tannin Tannins Precipitate Absorbance Specrtra pH extracted by mg tanning/g mg mg/g dry mg/mug tea Abs 570 nm Ratio the method dry weight tannin/mug weight equvalence # mug tea 270 nm/373 of the of tea equivalence nm invention equivalent 0.22% Brewed 39 151 28.3 109.8 0.130 10.27 5.0 Spent 37 143 37.0 91.6 0.129 9.63 5.0 Tea 200 0.176 69.4 0.061 1.85 x 10-5 69.58 4.2 Extract Loose Leaf Tea % tannin Tannins Precipitate Absorbance Spectra pH extracted mg tannin/g mg mg/g dry mg/mug tea Abs 570 nm Ratio by the dry weight tannin/mug weight equivalence @ mug tea 270 nm/373 method of of tea equivalence nm the equivalent invention 0.002% Brewed 67 266 34.6 134.2 0.092 13.72 5.0 Spent 66 256 37.0 143.6 0.098 12.88 4.9 Tea Extract 30 0.026 0* 0* 8.70 x 10-5 46.4 4.4 Green Tea % tannin Tannins Precipitate Absorbance Spectra pH extracted mg tannin/g mg mg/g dry mg/mug tea Abs 570 nm Ratio by the dry weight tannin/mug weight equivalence @ mug tea 270 nm/373 method of of te aequivalence nm the equivalent invention 0.00067% Brewed 54 210 22.9 88.8 0.043 11.39 5.7 Spent 50 194 27.6 107.1 0.036 10.48 5.9 Tea Extract 4.4 0.0039 0* 0* 4.88 x 10-5 40.3 4.4 *=undetectable

EXAMPLE 5 Adsorption of the tea extract onto a bulking agent; sorbitol/maltodextrins 2.4 mg of the tea extract produced in Example 1 were dissolved in 1 ml hexane with mixing and/or sonication. 20-50 mg maltodextrin or sorbitol were added and mixed by inversion for several minutes. A helium line was used to evaporate off the hexane. For maltodextrin and sorbitol an off- white free flowing powder was obtained. When resuspended in 1 ml distilled water a slightly hazy solution was obtained, and the support material was solubilised. Tea aroma remained on the solid and in solution.

EXAMPLE 6 Adsorption of tea extract onto herbal tea-Camomile 2 mg of the tea extract produced in Example 1 was dissolved in 2 ml hexane with mixing and sonication. 0.5 g camomile tea leaves were added and mixed by inversion for several minutes. Hexane was evaporated off on a helium line. The appearance of camomile tea impregnated with tea extract was identical to the original camomile tea. The aroma of camomile tea impregnated with the tea extract was different from the original with a stronger fruity, tea aroma.

EXAMPLE 7 Adsorption of tea extract onto instant tea products

1-1.5 mg of the tea extract produced in Example 1 were dissolved in 1 ml hexane with mixing-sonication as required. 0.1 ml instant tea granules (PG Tips or Lawrie freeze dried tea) were added and mixed by inversion. Hexane was removed under helium. PG Tips granules impregnated with tea extract were free flowing and similar in appearance to the original granules though some break up of the granules had occurred in the process. Lawrie freeze-dried tea powder produced a powder which appeared damp and clumpy compared to the original free flowing powder.

Both instant tea products with tea extract absorption had an improved strong tea aroma.

EXAMPLE 8 Adsorption of tea extract onto tea bag material 1 mg of the tea extract of Example 1 was dissolved in 1 ml hexane. One empty tea bag was added and mixed by inversion for several minutes. A second tea bag was placed in hexane alone. For both samples the hexane was evaporated to dryness under helium. The tea bag impregnated with tea extract was found to have a strong tea aroma compared to the control, which had virtually no tea aroma.

EXAMPLE 9 Solubility of tea extract in glycerol 1 ml of glycerol was added to 3.4 mg of tea extract. This was sonicated and mixed by turning for several minutes. The tea extract was partially soluble in glycerol. The glycerol was pale green in colour, and some yellowish

particulates remained. A further 2-4 ml glycerol was added and no further solubility was observed after mixing at a concentration of 1 mg/ml. The glycerol tea extract solution was pale green with a good strong tea aroma with some particulates remaining. This demonstrates the ability of solvents such as glycerol to act as carriers for the tea extract.

Comparative Example for Example 9 Solubility of freeze dried spent tea in glycerol 1 ml glycerol was added to 9.7 mg freeze-dried spent tea. This was sonicated and mixed by turning in glass bijoux for several minutes. The freeze-dried tea was partially soluble in 1 ml glycerol, giving an amber/brown solution with some brown particulates remaining. When a further 1 ml glycerol was added, the freeze-dried tea was mostly dissolved.

A further 1 ml, (3m total), glycerol was added and after mixing and gentle heating, the freeze-dried tea was found to be very soluble. An amber brown solution with a slight haze resulted.

EXAMPLES 10 to 12 Products in Tablet Form General Method The ingredients were weighed out and then well mixed to ensure even distribution between tablets. The required amount for the tablet was then

measured out into the mould, then subjected to high pressure by means of a tableting device.

The resulting tablets dissolved rapidly in cold water upon moderate agitation.

EXAMPLE 10 Effervescent tablet Ingredient % by weight Weight to give 100ml drink (g) Icing Sugar 85. 3 6.5 Sodium Bicarbonate 3.3 0.25 Citric Acid 4.6 0.35 Vanillin 0.1 0.01 Ascorbic Acid 0.1 0.01 Tea Extract on Maltodextrin* (20mg on 0. 4g) 1.3 0.1 Tea Retentate from method of the invention 5.3 0.4 Total 7. 62 *According to Example 5 EXAMPLE 11 Tea tablet containing tea extract plus commercially available tea extract

Ingredient % by weight Weight to give 100ml drink (g) IcingSugar 89. 8 5. 500g CitricAcid 1. 5 0. 090g LawrieTM tea extract 8. 15 0. 500g Ascorbic Acid 0. 3 0. 20g Tea extract on carrier** 0. 25 0. 015g* Total 6. 125 *equivalent to 0.74mg tea extract

**According to Example 5 EXAMPLE 12 Tablet containing freeze dried tea retentate Ingredient % by weight Weight to give 100ml drink (g) Icing Sugar 86. 5 6. 4g Sodium Bicarbonate 3. 4 0. 25g Citric Acid 4. 7 0. 35g Tea retentate 5. 4 0. 4g

EXAMPLE 13 Use of a sugar glass encapsulated tea extract

15 g of maltodextrin were added to 15 ml of distilled water and heated/mixed via a magnetic hotplate stirrer. The maltodextrin was seen to be solubilised upon heating and the solution was simmered until there had been a reduction in volume of about 20-30 % (approximately 0.5 hour) resulting in a viscous syrup.

About 2 ml of the resulting syrup was added to 5 mg of the tea flavour and mixed together by stirring with a micro-spatula. Although not solubilised, the tea extract was evenly dispersed throughout the maltodextrin. This was smeared onto watch glasses to give a thin layer, and placed into either a 40°C oven to dry overnight (16-20 hours) or left to air dry for approximately 48 hours. The remainder of the syrup was added to moulds, such as eppendorf tube caps (approximately 300 ul volume), which were then frozen in a-80°C freezer and lyophilised overnight (approximately 16- 20 hours).

A pale-green, crystalline solid was obtained from the air-and oven-dried samples. The freeze-dried samples produced a number of solid"tablets" that were also pale green.

The crystalline solids and tablets had no detectable tea aroma, but when dissolved in distilled water a tea aroma was obtained, indicating the tea extract was encapsulated in these sugar glass preparations. The mould employed, the volume and temperature of the samples to be freeze-dried can alter the appearance (eg, open or dense structure) of the tablets obtained.

EXAMPLE 14 A comparison of different tea extracts

Method Lapsang Souchong, Ceylon, Darjeeling, Kenyan, Green tea and leafs obtained from Sainsburys (a UK retail store) economy tea bags were extracted by the following methods. 75 g tea leaf was added to 625 ml boiling water. This was brought to the boil, stirred and stewed for 10 minutes. The tea was filtered and tea liquor made back to 625 ml. 200 ml hexane was transferred to a dialysis tube and knotted at both ends. Each tea was extracted for 20.5 hours, 200 rpm 30°C. Hexane was recovered from each tea sample and evaporated down under reduced pressure and taken to dryness under a stream of helium.

PG (trade mark) Instant tea granules were treated slightly differently.

Firstly, one teaspoon of instant tea and loose leaf tea were weighed and it was calculated how much instant tea was required to produce an equivalent taste of 75 g/625 ml brew of loose leaf tea.

The results are set out in the following table: Type of tea Aroma and Yield (mg Changes in Extract extract/75g tea volatile flavour leaf) chemical composition Lapsang Strong 33.4 Mostly similar to Souchong distinctive standard black smoky aroma. tea. 3 large Masks tea notes. peaks could be Yellow/orange responsible for oily extract. smoky aroma chromatographic retention times 22.7,28.7,30.9 Ceylon Rounded light 3.7 Very similar to tea aroma quite standard black flowery. tea some larger Yellow, oily peaks solid. Darjeeling Sharp, citrussy 3.2 Similar to aroma yellow, standard black oily solid tea some elevated peaks chromatographic retention times 24-30 Sainsburys'Strong tea 2.7 (w/w) Very similar to economy tea aroma, lacks 2.1 (taste) black tea bags body. Yellow solid Kenyan tea Strong tea aroma 4.0 Similar to with'antiseptic'standard black notes. Pale tea yellow solid Green tea Light flowery 2.8 Chromato- earthy tea aroma graphic retention yellow solid, non times peaks oily mostly the same as black tea, levels different RT42.1 elevated

EXAMPLE 15 A best mode of operating the present invention is indicated below.

Pressure, flow, temperature and time parameters may be varied for a particular experiment. The figures quoted below are functional ranges which are known to generate acceptable product.

Abbreviations: HF Hollow fibre HDPE High Density PolyEthylene MWCO Molecular Weight Cut Off L/hr Litres per hour barg Bar (pressure) gauge 1. Apparatus preparation (i) A hydrophilic hollow fibre membrane cartridge, for example Pall ACP1050 (MW CO 13,000 Da), is fitted to the apparatus of Figure 2.

(ii) Ensure that the shell side of the cartridge is free of gross moisture by examination of shell side liquid.

(iii) Ensure that the aqueous side of the membrane is clean by circulating fresh clean deionised water (3x1 litre) and checking wash pH value. This should be reduced to pH 7 +/-0.2 after washing. Membrane storage will typically have been at pH 8.5-9.

2. Tea preparation (i) Weigh out 150g of loose leaf tea into a clean, odourless 4L HDPE jug.

(ii) Charge the jug with 1250ml of fresh, boiling softened water at 93- 97 °C. Stir the leaves in the water to form a homogeneous mixture. Cover and allow to mash for the specified time, normally 10 minutes. Stir the mash once during the process to re-homogenise the mixture.

(iii) Remove the spent leaves, typically by use of a small hand press.

Approximately three pressings will be required for this volume of mash.

Traces of fines not removed in the press should be filtered out through a fine mesh gauze.

(iv) Note the volume of the mash recovered and adjust the volume back to 1250ml with hot water.

3. Separation apparatus operation (i) Drain any residual water wash from the aqueous side of the membrane. Ensure that wash pH reduced to 7.0 +/-0.2 before proceeding.

(ii) Charge the apparatus solvent reservoir with the specified volume of solvent, normally 10OOOml of n-hexane.

(iii) Start the apparatus solvent pump and ensure that flow has been established by observing solvent returning to the reservoir without gross amounts of entrained air.

(iv) Adjust the pump speed (air feed pressure) and solvent back-pressure valve to give the specified flow and solvent side pressure. Normal values: 100 L/hr, 0.34-0.41 bar.

(v) Charge the tea mash preparation from 2 (iv) above to the aqueous reservoir and note its temperature. Set the temperature control bath to the specified temperature (range 25-45°C) and switch on. Ensure that temperature control liquid is flowing through the coil.

(vi) Cool the tea mash liquor to-3°C above the specified running temperature (normally 35°C), ensure that solvent side pressure is as set above in 3 (iv), then start tea flow.

(vii) Adjust tea pump speed to give the specified flow, normally 200 L/hr, and note the tea side pressure. If necessary adjust hexane flow and pressure to return to the specified values for the solvent side. Ensure that a pressure differential of 0.2 bar is maintained between the solvent and aqueous sides.

(viii) Operate the apparatus for the time specified for the experiment (normally 60 minutes). Ensure that operating conditions are maintained during the batch by monitoring at specified intervals.

4. Stopping operation of apparatus

(i) At the end of the apparatus operation, time point in 3 (viii) above (typically 60 minutes), stop the aqueous flow by turning the tea mash pump off.

(ii) Drain the spent tea mash from the apparatus and sample for any analysis specified. Ensure that solvent flow is maintained during this process.

(iii) Recover the rich solvent extract, normally n-hexane, from the apparatus by releasing the solvent side back pressure. Slow the pump speed then open the solvent drain valve and collect the rich solvent extract in a measuring cylinder. Note the volume recovered.

(iv) Charge the solvent reservoir with the specified volume of rinse solvent, normally 200ml, and circulate for 3-5 minutes at-100 L/hr and minimal back pressure.

(v) Recover the washing as in 4 (iii) above and repeat the rinse as in 4 (iv) above.

(vi) Combine the washes with the bulk rich solvent extract.

5. Product recovery (i) Evaporate the solvent from the product under reduced pressure, normally-0.8 bar using a rotary evaporator set at a bath temperature of 30°C.

(ii) As the solvent, normally n-hexane, is evaporated a white floccular precipitate may be observed towards the end of concentration. At this stage transfer the concentrate to successively smaller flasks to ensure good mass recovery.

(iii) Finally, transfer the concentrate to a weighed 5ml Bijou bottle and dry product in a stream of inert gas, for example nitrogen.

(iv) Continue addition of concentrate from rotary evaporator flask to Bijou as required, rinsing flask with a few ml of fresh hexane when empty.

(v) Complete drying of product to a constant weight in the Bijou bottle, under an inert gas stream.

(vi) Typically 10-15 mg of extract is produced for the conditions specified in this document. Store the product at-20°C.