The present invention relates to a tea product and more particularly the present invention relates to a liquid concentrate tea product and process for producing the same.

Background of the invention

Tea is one of the most widely consumed beverages in the world. Teas with different natural additives are also quite popular. Honey is one of those naturally available materials that is believed to provide various health benefits.

Different kinds of beverages with honey or its essence are disclosed in the art.

CN1954682 (JIN ZHONGYING NANO SCIENCE, 2007) discloses a health-care plum-honey-green tea-vinegar beverage with improved taste and rich nutrients for patients of hepatocirrhosis and anorexia. It is prepared from plum, green tea, vinegar, honey, citric acid and essence.

CN1 185285 (CHUNDU GROUP CO LTD LUOGANG, 1998) discloses the production method of jasmine honey tea comprising (wt%) jasmine tea juice (10- 90), sophora flower honey (0.5-15) and cane sugar (5-15), and in the course of production the antioxidant Vc and VcNa are added, and the citric acid is used to regulate its pH value to protect its natural pH value.

Different formats of tea products are also available in the market. Liquid concentrate tea product being one of them. Liquid concentrate products usually diluted at consumer end to produce consumable beverage. After dilution consumer tends store it under refrigeration and consume the beverage within a period of 2-5 days. There is prior art which describes the production of shelf stable tea concentrates.

US 4539216 (The Procter & Gamble Co.) describes a process for the preparation of shelf-stable tea concentrates and tea powders wherein a tea extract is prepared, acidified, and heated; off-flavor and malodorous compounds are removed from the extract; the extract is cooled and precipitates are removed from it; and flavoring and sweetener are blended with the clarified extract. The acidification and heating steps accelerate acid-catalyzed degradation reactions that normally occur causing the development of off-flavor sulfurous compounds and precipitates.

US 4717579 (The Procter & Gamble Co.) describes frozen tea mix concentrates which contain high levels of sugar and are flowable at freezer temperatures. These tea mix concentrates comprise from about 0.5 to about 2% by weight tea solids and from about 40 to about 70% by weight of a sugar component.

US 4797293 (General Foods Corporation) describes a non-clouding, shelf-stable tea concentrate which is prepared by lowering the pH of a freshly-prepared concentrate (8 to 24% soluble solids) to between 2.9 and 3.5, chilling the concentrate to between 30 and 45 F, clarifying the concentrate to remove precipitate, and then elevating the pH of the clarified concentrate to between about 3.9 and 4.3.

US 4748033 (The Procter & Gamble Co.) describes a tea concentrate which is stable against flake formation during cyclic freezing and thawing, and which has enhanced solubility in cold water. The tea concentrate comprises from about 0.4 to about 8% by weight tea solids, an edible gum selected from xanthan gum, cellulose gums, locust bean gum, guar gum and mixtures thereof in specified amounts, and optionally a solubilizer selected from sugars, polyols and mixtures thereof in specified amounts. EP 0162526 (The Procter & Gamble Company) describes a shelf-stable tea mix concentrate comprising: (a) from about 0.05% to about 40% by weight tea; (b) from about 0.05% to about 40% by weight acid; (c) from about 0.5% to about 90% by weight sweetener; (d) water and flavorings in an amount sufficient to make up to 100% by weight; said shelf-stable concentrate contains no preservatives and a maximum sulfur content of 0.005% by weight.

Although the prior art describes processes for producing stable tea mix concentrates, none of these documents addresses the problem of haze formation when producing a liquid concentrate with honey and soluble tea solids.

We have found out that liquid concentrate tea product with honey when diluted at consumer end forms floe and make the solution turbid when storing the diluted beverage for 2-5 days under refrigeration. Consumers tend to waste/abandon the product when there is floe formation and/or increased turbidity.

Therefore there is a need to provide a liquid concentrated tea product with honey which substantially reduces floe formation and/or turbidity when diluting and storing the beverage.

Objects of the invention

It is therefore an object of the present invention to overcome or ameliorate at least one of the disadvantages of the prior art, or to provide a useful alternative.

It is another object of the present invention to provide a liquid concentrate tea product with honey.

It is yet another object of the present invention to provide a process for producing a liquid concentrate tea product with honey. It is a further object of the present invention to provide a process for producing a liquid concentrate tea product with honey which substantially reduces floe formation and/or turbidity when diluted and stored. The present inventors have surprisingly found that instead of simply mixing the ingredients, a process modification involving addition of acidulant followed by separation of the insoluble solids leads to a liquid concentrate tea product with honey which substantially reduces floe formation and/or turbidity when diluted and stored and therefore satisfies one or more of the above mentioned objects.

Summary of the invention

In a first aspect the present invention provides a process for producing a liquid concentrate tea product with honey comprising the steps of:

a) mixing soluble tea solids, honey and water for 2 - 30 minutes at a temperature of 60 to 95 °C;

b) adding a sufficient amount of acidulant to make the pH of the solution in the range of 2.5 -3.5;

c) reducing the temperature of the solution to 15 - 40 °C;

d) separating out any insoluble solids to obtain a supernatant; and, e) adding a solubilizer selected from ethanol, propan-1 ,2-diol, glycerin, propelyne glycol, polyphthylene glycol or mixtures thereof, to the supernatant and mixing to obtain the tea product.

In a second aspect the present invention provides a liquid concentrate tea product as obtained and/or obtainable by the process of the first aspect.

Any feature of one aspect of the present invention may be utilized in any other aspect of the invention. The word "comprising" is intended to mean "including" but not necessarily "consisting of or "composed of." In other words, the listed steps or options need not be exhaustive. Except in the operating and comparative examples, or where otherwise explicitly indicated, all numbers in this description indicating amounts of material or conditions of reaction, physical properties of materials and/or use are to be understood as modified by the word "about". Numerical ranges expressed in the format "from x to y" are understood to include x and y. When for a specific feature multiple preferred ranges are described in the format "from x to y", it is understood that all ranges combining the different endpoints are also contemplated.

Detailed description of the invention

Liquid concentrate tea product preferably means a tea product in dense liquid form which is diluted at the consumer end to obtain a beverage. The beverage is preferably a cold beverage.

Cold beverage preferably means a beverage that is obtained and/or obtainable by diluting the liquid concentrate tea product of the present invention with cold (~ 0°C to 10°C) water.

The viscosity of the liquid concentrate tea product of the invention is preferably in the range of 35 to 70 Centipoise and more preferably in the range of 40 to 60 Centipoise at room temperature (~25°C). According to one embodiment, the present invention provides a process for producing a liquid concentrate tea product with honey comprising the steps of: a) mixing soluble tea solids, honey and water for 2 - 30 minutes at a temperature of 60 to 95 °C;

b) adding a sufficient amount of acidulant to make the pH of the solution in the range of 2.5 -3.5;

c) reducing the temperature of the solution to 15 - 40 °C;

d) separating out any insoluble solids to obtain a supernatant; and, e) adding solubilizer selected from ethanol, propan-1 ,2-diol, glycerin, propelyne glycol, polyphthylene glycol or mixtures thereof, to the supernatant and mixing to obtain the tea product. First, the soluble tea solids, honey and water is mixed for 2 -30 minutes, preferably for 5 to 30 minutes and most preferably for 10 to 30 minutes at a temperature of 60 to 95°C preferably 75 to 95°C. After that, a sufficient amount of acidulant is added to make the pH of the solution in the range of 2.5 - 3.5, followed by reducing the temperature of the solution to 15 - 40°C and preferably to 15 - 30°C. After that the insoluble solids are separated out from the solution to obtain a supernatant. This separation step may be achieved by any separation technique preferably by centrifugation. It is then followed by taking the supernatant and adding the solubilizer and then mixing it properly to obtain the liquid concentrate tea product.

At step (e), a further addition of acidulant is preferable as this increases the microbial stability by maintaining a pH of about 2.5 - 4.

When adding the acidulant in a stepwise manner, the present inventors have found that that out of total amount of acidulant used in the formulation, 30 - 40% is preferably required in step (b) of the above described process to bring down the pH in between 2.5 - 3.5.

The remaining 60 - 70 parts of the acidulant is preferably added at step (e).

The tea product as obtained may be pasteurized before storing it in a bottle or in any other suitable container.

The amount of tea solids added preferably is in the range of 1 -10 %, more preferably 2 - 10% and most preferably 3 - 10% by weight of the tea product. Soluble tea solids refer to tea solids that are readily soluble in water and more preferably in cold water (~ 0°C to 10°C). The soluble tea solids may be prepared by extracting tea leaf using water as an extraction medium. Commercially available soluble tea solids may also preferably be used.

Alternatively tea soluble solids are obtained by extracting the leaf tea in hot water (-80° to 95° C) for 30 minutes to 2 hours followed by cooling the solution to ~2C to 8°C. After that the solution is filtered and spray dried to obtain the soluble solids. Preferably the soluble tea solids are obtained and/or obtainable by processing Camellia sinensis plant. The preferable variety is Camellia sinensis var. sinensis and/or Camellia sinensis var. assamica. Especially preferred is material from var. assamica.

The amount of honey added preferably is in the range of 10 - 25% more preferably 12 - 25%, further more preferably 15 - 25% and most preferably 17 to 25% by weight of the tea product. Honey is a well known natural sweet food (highly viscous) made by bees using nectar from flower. The nectar collected by bees is naturally broken down into simple sugars (fructose and glucose) and stored in honeycomb. Evaporation takes place inside the honeycombs and thus produces a thick liquid known as honey. After this, the beekeepers collect the honey from the honeycomb by separating the wax and the honey. Honey also contains small amounts of polysaccharides, flavonols and proteins.

Honey has a unique taste which is preferred by a lot of people. Honey is also believed to be of high nutrition value with a number of health benefits. A number of people refer it as a natural energy booster. Regular consumption of honey is believed to improve the immune system within the human body.

Without wishing to be bound by theory, it is believed that the haze formation in the present case is due to the interaction between proteins (present in honey) and polyphenols (constituents of tea). Without wishing to be bound by theory, it is also believed that solubilizer is a compound which is required to stabilize a liquid product with honey, water, tea solids and other compounds which otherwise tends to phase separate. Another advantage of using a solubilizer is that it maintains the viscosity required for a concentrated product. As mentioned above, the viscosity of the product is preferably in the range of 35 to 70 Centipoise. The amount of solubilizer added preferably is in the range of 35 - 55 %, more preferably 40 - 55 % and further more preferably 45 - 55 % by weight of the tea product. The present inventors have found that honey, when combined with water and the other ingredients of the composition tends to phase separate. The advantage of addition of solubilizer is that it tends to prevent this phase separation. Any solubilizer that may be used for food application may be used. The solubilizer is selected from ethanol, propan-1 ,2-diol, glycerin (glycerol), propelyne glycol, polyphthylene glycol (PEG). The most preferable solubilizer is glycerin.

The amount of acidulant added preferably is in the range of 1 - 6%, more preferably 2 - 5% and further most preferably 3 - 5% by weight of the tea product. This is added for maintaining the desired pH of the product. The pH of the liquid concentrate tea product is in the range of 2.5 to 4, more preferably 3 - 3.5. Any suitable food grade acidulant may be added for this purpose. The most preferable acidulant is citric acid. Acidulant maintains the pH of the product.

The amount of water added preferably is in the range of 5 - 50%, more preferably 10 -45 %, further more preferably 20 - 40% and most preferably 25 - 35% by weight of the tea product.

Optionally 0.01 - 1 %, more preferably 0.03 to 1 % and most preferably 0.05 to 0.5% by weight of a preservative is also added. The preservative may preferably be selected from sorbic acid and its derivatives, sodium benzoate, benzoic acid or mixtures thereof.

Other additives e.g. fortificants, colour, flavour and any other additives suitable to be used for beverage composition may also be added in the tea product.

The present invention also provides a liquid concentrate tea product as obtained and/or obtainable by the process of the present invention. Now the invention will be demonstrated in terms of examples. The following examples are just for illustration and in no way limits the scope of the present invention.

Examples

Preparing the liquid concentrate tea product:

The liquid concentrate tea product was prepared as per the following Table 1 :

Table 1

For this purpose: soluble tea solids were obtained from Martin Bauer Group (Product Catalogue No: 22949/12), citric acid was obtained from Sigma (Catalogue No: C0759), glycerin was obtained from Mediplus Pharma Lab Bangalore (IP grade), sorbic acid was obtained from Sigma (Catalogue No: S1626) and honey was obtained from Dabur India Pvt. Ltd.

The water used was Milli Q water (Millipore® India). The conductivity of the Milli Q water was 18.2 MQ.cm at 25°C. The Ca ⁺⁺ content of the Milli Q water was 0.1 ppt (which is negligible).

Example A:

This is a control example. In this example soluble tea solids, citric acid, sorbic acid was added in water (~95°C) in their respective amount as per Table 1 . This mixture was taken in a beaker and placed on a hot plate maintained at a temperature of 70 ± 2 °C with constant stirring for 10 minutes. After that Honey and glycerin was added into the beaker and then again stirred for another 10 minutes on the same hot plate and transferred to a bottle as a product. Example B:

This example is same as example A except that honey was not added, the amount of water in the formulation was adjusted accordingly.

Example C:

This example is same as example A except that sugar was added instead of honey.

Example 1 :

In this example the liquid concentrate tea product was prepared as per the process of the present invention. Tea solids, honey, water (~95°C) was added and the solution was stirred on a hot plate maintained at a temperature of 70 ± 2 °C for 10 minutes. 1 .2g (for each 100 g of formulation) of citric acid was then added into this solution to bring down the pH to about 2.5. After that the solution was cooled down to room temperature (~25°C) followed by centrifuging the solution in a centrifuge (Beckman Coulter Centrifuge, Avanti - J30I) at 1 1295g for 45 minutes. The supernatant was then collected and glycerin, sorbic acid and the remaining 2.8g of citric acid (for each 100 g of formulation) was added to it. This solution was then again stirred for 10 minutes on a hot plate at a temperature of 70 ± 2 °C and transferred in a bottle as a product.

Turbidity measurement:

The liquid concentrate tea products as prepared above was taken and diluted with Milli Q water (Millipore® India) at a level of 1 :10, 1 :20 and 1 :30. After that all the solutions were stored under refrigerated condition (~4°C) for 2 days (-48 hours). After 2 days the solutions were taken out and brought to ambient temperature (~25°C) (to avoid condensation outside the cell). Then the turbidity was measured. The turbidity was measured using a turbidity meter (HACH, 2100N). The results of the experiment are summarized below in Table 2:

Table 2

From the above Table 2, it is evident that liquid concentrate tea products prepared according to the process of the present invention (Example 1 ) produces a product having much lower turbidity when compared with Example A. This means the diluted beverage of Example 1 appearing significantly clear when compared to the control (Example A). The effect is more pronounced in the lower dilution. It is also clear from the above table that honey enhances the turbidly in the formulation in presence of tea solids. The formulation without honey (Example B) and the formulation with other sweetener e.g. sugar (Example C) have significantly less turbidity than Example A. The liquid concentrate tea product prepared according to the present invention also visually appears clear (with no floe) when compared with the respective control (with floe).

Thus it is evident from the above description that by way of present invention it is now possible to provide a process for producing a liquid concentrate tea product with honey which substantially reduces floe formation and/or turbidity when diluted and stored.