Title of Invention

A PROCESS FOR MAKING A POWDER TEA PRODUCT

Abstract

A process for making a powder tea product which can be reconstituted to give a milked tea beverage, said process comprising the steps of: a) adjusting the pH of a liquid milk product to a value in the range 6.0 to 7.5 b) heat treating the liquid milk product by maintaining the temperature of the liquid milk product in the range 70 to 90°C for sufficient time to bind p-lactoglobulins to the surface of the casein micelles in the liquid milk c) concentrating the resulting liquid milk product to a solid content of 35 to 60% by weight d) combining the concentrated liquid milk with a tea concentrate, and e) drying the resulting product to give the powder tea product.

Full Text

F3309 FORM -2 THE PATENTS ACT, 1970 (39 of 1970) COMPLETE SPECIFICATION (See Section 10) HINDUSTAN LEVER LIMITED, a company incorporated under the Indian Companies Act, 1913 and having its registered office at Hindustan Lever House, 165/166, Backbay Reclamation, Mumbai -400 020, Maharashtra, India The following specification particularly describes the nature of the invention and the manner in which it is to be performed. TEA PRODUCT FIELD OF THE INVENTION The present invention relates to feoa produetg- for making BO.Heed tea bovoragog', particularly those that produce little or substantially no sediment when prepared for consumption by the consumer. BACKGROUND OF THE INVENTION Apart from water, tea is consumed in greater volumes than any other beverage. In the Western world most of that tea is so-called "black tea" which is obtained from the leaves of the plant Camellia sinensis by processes that allow polyphenols in the leaf to be oxidised by enzymes within the leaf (such as polyphenol oxidase) to produce the coloured polymeric materials that are responsible for the characteristic colour of black teas and of the infusions made from them. In seventeenth century England, when tea was a luxury and taken in porcelain cups, tea drinkers were concerned that pouring hot tea directly on to the delicate cup would cause it to crack, so they began to add a small amount of milk first. In many countries, consumers still prefer to add milk to black tea before consumption. Milk reacts chemically with tea. One of its components, called casein, binds with the tannins in tea to give the milked tea beverage a smoother, less astringent taste. Traditionally such milked tea beverages have been prepared by infusing leaf tea, more recently contained in a tea bag, with boiling water in a suitable container such as a tea pot or drinking vessel for sufficient time to give the strength and colour required by the consumer. The infusion is then mixed with liquid milk prior to ingestion by the consumer. The preparation of a tea beverage in this way is considered by many to be time-consuming and consumers today demand convenience but still expect to drink a quality beverage. When it is inconvenient to prepare the tea beverage by infusion consumers may use powdered tea products which can be reconstituted with hot water to give the tea beverage. Such powdered tea products are often used to make tea beverages in beverage dispensing machines. When liquid milk is not readily available consumers may use a milk substitute instead. These milk substitutes are generically known as whiteners, usually containing a portion of non-dairy fat and may be available as liquids or powders. However when such milk substitutes are used with tea infusions or with beverages made from reconstituted tea powders they do not always meet the consumer's expectations. Unfortunately powdered milk products tend to form a sediment when added to tea beverages. Although this may have only a minor impact on the taste of the final product it is not aesthetically pleasing to consumers. They might even perceive the product as lacking quality. It is therefore desirable to minimise any sedimentation. Sediment formation is believed to occur as a result of an interaction between the polyphenols found in tea and proteins found in the milk. Others have struggled with the interaction between milk substitutes and beverages such as tea. For example, US patent specification 4,980,182 discloses ready to serve coffee or tea based beverages that contain milk protein. Kappa carrageenan, buffering and chelating agents including a phosphate and at least one of sodium alginate and propylene glycol alginate are added to enhance the colloidal stability of the composition. The mixture is heat treated to sterilise it and aseptically packaged to give a long shelf life at room temperatures. European patent specification 133,772 discloses a method of producing a soluble or dissolved tea product. Water soluble caseinate is added to tea liquor to prevent tea cream formation and thus enable the tea to be processed or distributed as a homogeneous liquid, at temperatures down to the point where it becomes frozen. French patent specification 2,122,417 describes a process for making an optionally carbonated chilled tea beverage at normal strength without concentration. Soluble caseinate is used as a stabiliser to retard sedimentation. The powder tea product preferably contains 50 to 75, preferably 55 to 70% by weight of milk solids and 25 to 50, preferably 30 to 45% by weight of tea solids ID IE A second aspect of the present invention provides a process for making a powder tea product which can be reconstituted to give a milked tea beverage, said process comprising the steps of:- a) adjusting the pH of a liquid milk product to a value in the range 6.0 to 7.5 b) heat treating the liquid milk product by maintaining the temperature of the liquid milk product in the range 70 to 90°C for sufficient time to bind /S-lactoglobulins to the surface of the casein micelles in the liquid milk c) concentrating the resulting liquid milk product to a solid content of 35 to 60% by weight d) combining the concentrated liquid milk with a tea concent rat e, and e) drying the resulting product to give a powder tea product which can be reconstituted to give a milked tea beverage A further aspect of the present invention provides a process for making a powder tea product which can be reconstituted to give a milked tea beverage, said process comprising the steps of:- a) adjusting the pH of a liquid milk product to a value in the range 6.0 to 7.5 b) heat treating the liquid milk product by maintaining the temperature of the liquid milk product in the range 70 to 90°C for sufficient time to bind jS-lactoglobulins to the surface of the casein micelles in the liquid milk c) drying the resulting liquid milk product to give a powdered milk product d) mixing the powdered milk product with a tea powder to give the powder tea product. Another aspect of the present invention provides a process for making a powder tea product which can be reconstituted to give a milked tea beverage, said process comprising the steps of:- a) adjusting the pH of a liquid milk product to a value in the range S,0 to 7.5 b) heat treating the liquid milk product by maintaining the temperature of the liquid milk product in the range 70 to 90°C for sufficient time to bind jS-lactoglobulins to the surface of the casein micelles in the liquid milk c) drying the resulting liquid milk product to give a powdered milk product d) mixing the powdered milk product with a tea powder, and e) coagglomerating the resulting mixture to give the powder tea product. The liquid milk product may be full cream milk or may be partially or fully skimmed. The fat content of the liquid milk product may be adjusted by the addition of additional fat if required before the heat treatment step. The liquid milk product may be demineralised, homogenised and/or pasteurised before the heat treatment. Additional materials may be added to the liquid milk product before the heat treatment, for example a) whey protein isolate and/or whey protein concentrate may be added to increase the whey protein to casein ratio of the liquid product. Preferably whey protein isolate is used. If whey protein concentrate is used it may be obtained from sweet or acidic whey though sweet whey is preferred due to its low ionic calcium content. b) transglutaminase may be added to covalently crosslink proteins and consequently to fix their associative state c) a synthetic fat replacer (for example that sold under j the trade mark Simplesse by Kelco (for example Simplesse 100) may be added to give increased body d) propylene glycol alginate may be added to provide a desirable mouthfeel. 1) Preferably the pH of the mixture is adjusted to within the range 6.2 to 7,1 most preferably pH 6.6. The heat treatment step preferably takes place at a temperature in the range 70 to 80°C, more preferably at around 75°C. The period during which the temperature is maintained in the ranges specified above will depend on the temperature at which the heat treatment occurs but will usually be in the range 1 to 10 minutes, preferably around 5 minutes at 75°C. The above heat treatment step may be preceded by a pretreatment step in which the temperature is maintained at a temperature of around 50°C for around five minutes to promote migration of unassociated jS-casein into the micelles. The concentration step may be performed using apparatus known in the art for this purpose, for example a reduced pressure/vacuum concentrator or falling film evaporator. The liquid milk product may be concentrated to a solids content of 35 to 50% more preferably 40 to 45%. The product of the concentration step may be optionally cooled to 10 to 15°C before the tea concentrate is added. The tea concentrate may be form of a liquid or a powder which may optionally contain additional flavouring agents. The tea concentrates for use in the present F3309cs(C) invention are preferably prepared from black (ie fermented) teas. These tea concentrates may be prepared using either a simple extraction process or an enzymatically assisted extraction process. In such extraction processes the leaf teas are preferably combined with water in an extractor at the desired temperature to obtain a tea extract slurry. Enzymatically assisted extraction, if used, requires the addition of enzyme(s) to the extractor during or prior to extraction. If a mixture of enzymes is used it may be added in the form of a cocktail or the enzymes may be fed to the extractor individually. Tea concentrates produced with enzymes may be prepared by treating leaf tea with an enzyme cocktail including selected cell wall lysis enzymes such as carbohydrase, cellulase, hemicellulase and/or xylanase. A suitable enzyme is available commercially as Viscozyme L™ (obtainable from NOVO Industri A/S Denmark) which is a multi-enzymecarbohydrase/cellulase/hemicellulase/xylanase complex. The tea extract slurry containing the enzymes is then hot extracted to complete the extraction process and the leaf tea is separated from the tea extract. The tea extract is then preferably pasteurised. This heat treatment deactivates the enzymes. The tea extract is optionally concentrated and polished by centrifugation or other clarification methods such as filtration and the like. After polishing, the extract is then either (a) concentrated (for example by vacuum concentration)to give liquid tea concentrates for use in the present invention, and/or (b) dried (for example by spray drying) to give powder tea concentrates for use in the present invention. Liquid tea concentrates for use in the present invention preferably contain from about 20 to about 70% of tea solids, preferably from 3 0 to about 65% by weight tea solids. The combined concentrated milk product and the tea F3309cs(C) concentrate preferably have a solids content of 40 to 45%, more preferably 42 to 44% solids. The coinbined concentrated milk product and the tea concentrate are preferably dried by spray drying in a three stage spray i drier. The resulting powder tea product may then be packaged into any suitable packaging. Sufficient powder for a single serving may be placed in a sachet or the powder may be packaged in a container holding several servings. The powder may be reconstituted by the user by adding water. To prepare a hot beverage the temperature of the water is preferably in the range 70 to 95°C). The powder may be reconstituted in the drinking vessel (eg a cup) from which the consumer intends to drink the tea beverage. The powder may also be used in beverage dispensing machines in which a measured amount of water at the appropriate temperature is mixed with the powder before the resulting tea beverage is directed into a drinking vessel which the consumer removes from the vending machine. The tea product prepared as above gives minimum sediment when reconstituted. The tea product also has good whitening characteristics due to its particle size distribution and a mouth feel typical of freshly milked tea. An alternative embodiment of this invention is prepared by blending a milk powder from a liquid concentrate which has been treated according to the above method with a tea powder and flavourings if required to produce a powder tea product which can be reconstituted with water to give a milked tea beverage A further embodiment of this invention is prepared by the co-agglomeration of a powdered milk product prepared from a liquid concentrate that has been treated according to the above method with a tea powder to give a powder tea product which can be reconstituted with water to give a milked tea beverage. DETAILED DESCRIPTION OF THE INVENTION Black tea infusions are known to contain polyphenols which give the infusions their characteristic colour and flavour. The major polyphenols in such infusions are catechins, theaflavins and thearubigins, their levels are approximately 3-5%, 3-8% and 25-35% respectively. Polyphenols are known to interact with proteins, particularly proline-rich proteins such as casein. The content of caffeine is about 6-7%. Milk proteins may be divided into two main groups: caseins and whey proteins. The caseins in bovine milk comprise 80% of the total milk protein. They have an open, random coil structure and a flexible conformation. They also have hydrophobic and hydrophilic regions and form micelles. One of the caseins is K-casein. It has a hydrophobic N-terminal, and hydrophillic C-terminal and a cysteine residue. It is the major casein on the surface of the casein micelles. The major whey proteins, which are 20% of total milk protein, are jS-lactoglobulin (9.8%) and a-1actalbumin (3.7%). Whey proteins have a globular, compact conformation and jS-lactoglobulin has a single buried free thiol group and two cysteine groups. Sediment is believed to be a direct consequence of the interactions between casein and tea polyphenols. The free thiol group of jS-lactoglobulin is can be denatured such that its structure unfolds with the concomitant exposure of this thiol group. The cysteine residue in K-casein contains two thiol groups attached to each other. These thiol groups are fairly unreactive under ambient conditions but undergo thermal reduction when heated. This thermal reduction is catalysed by the exposed thiol group of -lactoglobulin. Once in the reduced form the thiol groups of the casein molecule take part in a sulphydryl-disulphide interchange reaction between the thiol groups of the K-casein and thiol groups of the ^-lactoglobulin at the surface of the casein micelles. This interchange reaction blocks the free thiol groups on the surface of the casein and prevents tea polyphenols from binding to micelles of casein and consequently stabilises the micelles. /S-Lactoglobulin can also self-aggregate by forming disulphide bridges between two molecules. These large aggregates will reduce the capacity to complex with tea polyphenols. The invention will now be illustrated by the following description which is given by way of example only. Example 1 Bulk raw milk was standardised to a fat level of 0.19% and then pH adjusted to pH 6.59, using lactic acid (80%), prior to being homogenised and pasteurised. Following pasteurisation, the pH was re-adjusted to 6.59. The milk was heated at a temperature of 75°G for 5 minutes, and evaporated to 42.5% (w/w) solids using a falling film evaporator. The resulting milk concentrate (301kg) was held at 55°C in a jacketed vessel. De-ionised water (113kg) was heated to 90°C in a vacuum mixer (Limitech), and conventional instant tea powder (75kg) was mixed in using a high shear mixer under vacuum for 3 minutes. The resulting tea liquor had a solids level of 39% (w/w). Liquid tea flavour (lOOg) was mixed into the tea liquor using gentle agitation, again under vacuum, for a further 3 minutes. The resulting liquor was reheated to 90°C and pumped onto the milk concentrate in the jacketed vessel. The combined mix was cooled to 55°C and stirred 5 continuously. The mixture was then pre heated to 60°C and spray dried. An integral fluidised bed with fines recycle into the spray drier was used to give a powder with a bulk density of 400kg/m3 containing 63% milk solids and 37% tea solids based on the weight of the powder tea product. Example 2 Bulk raw milk was standardised to a fat level of 0.19% and then pH adjusted to pH 6.59, using lactic acid (80%), prior to being pasteurised. Following pasteurisation, the milk was preheated to a temperature of.75°C and held for 5 minutes, and was then evaporated to 47% (w/w) solids using a falling film evaporator. 400kg of the subsequent milk concentrate was held at 55°C in a jacketed vessel. The milk was the re-heated to 80°C for 90 seconds and then spray dried, using fines recycle and an integral fluidised bed to give a well agglomerated powder with a bulk density of SBOkg/m^ . This milk powder was then blended in a Nauta mixer with tea powder and a flavouring, in the ratio: milk 59%, tea 38% and flavouring 3%, yielding a final instant milked 0 tea powder. Example 3 Samples of the powder tea product (1.3g) made according l5 to Example 2 were infused in distilled water (175ml) at around 80*C. The resulting infusion was centrifuged at 400g for five minutes while still hot. The supernatant liquid was removed by decantation and the residue weighed. The residue represents the amount of sediment present in the infusion. The average amount from four experiments is given below in Table 1. The amount is expressed as the number of grammes of residue in 100 ml of the infusion. Samples of a tea product containing the same instant tea powder used to make the powder tea product of Example 1 and a commercially available dried milk product were treated as in the previous paragraph. The average amount of residue from four experiments is given in Table 1 below. Table 1 2D Amount (g.100ml ) Residue from powder tea product of Example 2 0.972 ± 0.172 Residue from product containing tea powder and dried milk 2.145 ± 0.616 25 The results in Table 1 clearly show that there is more residue (sediment) from the product which is a mere mixture of tea powder and dried milk which has not been treated in accordance with the present invention. The supernatant liquids from above were filtered through Watman No. 113 filter paper and the absorbance of the filtrate and amount of solids left after drying of the filtrate were measured. The absorbance indicates the amount of tea and milk solids which were dispersed in the infusion. A greater amount of these solids indicates that the infusion is of better quality as it contains more solids which did not form sediment. The absorbance readings were measured at 440nm with a 1mm pathlength. Table 2 below gives the average absorbance from four experiments. Table 2 Absorbance at 440nm Residue from powder tea product of Example 2 0.790 ± 0.085 Residue from product containing tea powder and dried milk 0.235 ± 0.0.008 15 The average weight of the residues left when four samples of the filtrate were evaporated to dryness are given below in Table 3. In this experiment a larger amount of residue indicates that more solids were retained in the infusion which could not be removed by centrifugation or filtration. The results in Table 3 are expressed as a weight/volume percentage. Table 3 20 Amount (% w/v) Residue from powder tea product of Example 2 0.634 ± 0.004 Residue from product containing tea powder and dried milk 0.500 ± 0.010 The results above show that the powder tea product according to the present invention produces less sediment and gives a higher quality product. WE CLAIM: 1. A process for making a powder tea product which can be reconstituted to give a milked tea beverage, said process comprising the steps of: a) adjusting the pH of a liquid milk product to a value in the range 6.0 to 7.5 b) heat treating the liquid milk product by maintaining the temperature of the liquid milk product in the range 70 to 90°C for sufficient time to bind p-lactoglobulins to the surface of the casein micelles in the liquid milk c) concentrating the resulting liquid milk product to a solid content of 35 to 60% by weight d) combining the concentrated liquid milk with a tea concentrate, and e) drying the resulting product to give the powder tea product. 2. A process for making a powder tea product which can be reconstituted to give a milked tea beverage, said process comprising the steps of: a) adjusting the pH of a liquid milk product to a value in the range 6.0 to 7.5 b) heat treating the liquid milk product by maintaining the temperature of the liquid milk product in the range 70 to 90°C for sufficient time to bind p-lactoglobulins to the surface of the casein micelles in the liquid milk c) drying the resulting liquid milk product to give a powdered milk product d) mixing the powdered milk product with a tea powder to give the powder tea product. 3. A process for making a powder tea product which can be reconstituted to give a milked tea beverage, said process comprising the steps of: a) adjusting the pH of a liquid milk product to a value in the range 6.0 to 7.5 b) heat treating the liquid milk product by maintaining the temperature of the liquid milk product in the range 70 to 90°C for sufficient time to bind P-lactoglobulins to the surface of the casein micelles in the liquid milk c) drying the resulting liquid milk product to give a powdered milk product d) mixing the powdered milk product with a tea powder, and e) coagglomerating the resulting mixture to give the powder tea product. 4. A process as claimed in any one of Claims 1 to 3 wherein the pH is adjusted to a value in the range 6.2 to 7.1. 5. A process as claimed in Claim 4 wherein the pH is adjusted to around 6.6. 6. A process as claimed in any one of Claims 1 to 3 wherein the heat treatment step takes place at 70 to 80°C. ^th Dated this 20 day of June 2003.

Documents:

645-mum-2003-abstract(20-6-2003).pdf

645-mum-2003-abstract(granted)-(14-6-2007).pdf

645-mum-2003-annexure to form 3(23-2-2004).pdf

645-mum-2003-cancelled pages(09-07-2004).pdf

645-MUM-2003-CLAIMS(20-6-2003).pdf

645-mum-2003-claims(amended)-(9-7-2004).pdf

645-mum-2003-claims(complete)-(20-6-2003).pdf

645-mum-2003-claims(granted)-(09-07-2004).doc

645-mum-2003-claims(granted)-(09-07-2004).pdf

645-mum-2003-claims(granted)-(14-6-2007).pdf

645-MUM-2003-CORRESPONDENCE(8-2-2012).pdf

645-mum-2003-correspondence(ipo)-(14-06-2007).pdf

645-mum-2003-correspondence(ipo)-(23-7-2007).pdf

645-mum-2003-correspondence1(23-06-2003).pdf

645-mum-2003-correspondence2(02-08-2004).pdf

645-mum-2003-description(complete)-(20-6-2003).pdf

645-mum-2003-description(granted)-(14-6-2007).pdf

645-mum-2003-form 1(20-06-2003).pdf

645-mum-2003-form 1(20-6-2003).pdf

645-mum-2003-form 19(23-06-2003).pdf

645-mum-2003-form 2(complete)-(20-6-2003).pdf

645-mum-2003-form 2(granted)-(09-07-2004).doc

645-mum-2003-form 2(granted)-(09-07-2004).pdf

645-mum-2003-form 2(granted)-(14-6-2007).pdf

645-mum-2003-form 2(title page)-(complete)-(20-6-2003).pdf

645-mum-2003-form 2(title page)-(granted)-(14-6-2007).pdf

645-mum-2003-form 3(20-06-2003).pdf

645-mum-2003-form 3(20-6-2003).pdf

645-mum-2003-form 5(20-06-2003).pdf

645-MUM-2003-GENERAL POWER OF ATTORNEY(1-12-2003).pdf

645-mum-2003-power of attorney(08-12-2003).pdf