F3441/C FORM - 2 THE PATENTS ACT, 1970 (39 of 1970) & The Patents Rules, 2003 COMPLETE SPECIFICATION (See Section 10 and Rule 13) FROZEN CONFECTIONS HINDUSTAN UNILEVER 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 invention and the manner in which it is to be performed F3441(C) FROZEN CONFECTIONS Technical Field of the Invention The present invention relates to frozen confections such as ice cream, in particular to frozen confections having a low glycemic index. Background to the invention Frozen confections normally contain relatively high amounts of sugar. In recent years there has been an increasing demand from consumers for frozen confections containing reduced amounts of sugar, for example because of health concerns relating to obesity, and diseases such as type 2 diabetes. The importance of limiting the content of sugars in a healthy diet has recently been highlighted by a Joint WHO/FOA Expert Committee (see "Diet, nutrition and the prevention of chronic diseases" - Report of a Joint WHO/FAO Expert Consultation, WHO Technical Report Series 916, WHO, Geneva, 2003). Recently, there has been a particular demand for frozen confections having a low glycemic index (Gl) value. The glycemic index is a measure of the blood glucose / insulin response to food consumption, i.e. how quickly the food raises the blood glucose levels. It is measured on 100 point scale, where glucose is set at 100. A low Gl value means that the food produces a small rise in the blood glucose level, i.e. it releases energy slowly, which helps to suppress the feeling of hunger, reducing the temptation to snack. A low Gl diet is believed to help weight loss, lower blood lipid levels and improve the body's sensitivity to insulin. Ice creams typically have a high Gl (in the range 60-80), although reduced Gl ice creams are also known. For example, Norco Co-opertative Limited, New South Wales, Australia produce an ice cream containing skim milk, sucrose, inulin and cream which is stated to have a Gl of 47. It is desirable to produce frozen confections having even lower Gl values. This cannot be achieved by simply reducing the sugar content of frozen confections since the resulting products are too hard (because of the reduced freezing point depression) and insufficiently sweet-tasting. Therefore, there remains a need for frozen confections having lower Gl and which maintain an acceptable texture and level of sweetness. F3441(C) Tests and Definitions Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art (e.g. in frozen confectionery manufacture). Definitions and descriptions of various terms and techniques used in frozen confectionery manufacture are found in Ice Cream, 6th Edition, Robert T. Marshall, H. Douglas Goff and Richard W. Hartel (2003), Kluwer Academic/Plenum Publishers. All percentages, unless otherwise stated, refer to the percentage by weight, with the exception of percentages cited in relation to the overrun. Glycemic Index (Gl) Glycemic Index is defined as the incremental area under the blood glucose response curve for a portion of a test food containing 25g carbohydrate, expressed as a percentage of the response to the same amount of carbohydrate from a standard food taken by the same subject (Food and Agricultural Organization (1998), FAO Food and Nutrition Paper No. 66, Food and Agriculture, Rome, Italy). Although 50g samples are often used when measuring Gl, some of the samples described below contain very low amounts of carbohydrates, so to deliver 50g carbohydrate would require a very large portion size. Using a portion containing 25g made the portion size more reasonable. The standard food used is glucose in water, and the Gl is expressed relative to glucose where glucose is assigned a Gl of 100. Consuming glucose results in a substantial increase in blood glucose levels, which is reflected in this Gl value which is high in comparison to most foods. Glucose (sometimes also called dextrose) is a monosaccharide sugar. Gl values have been measured for a large number of food ingredients, see for example the International Table of Glycemic Index and Glycemic Load Values: 2002, American Journal of Clinical Nutrition, Vol. 76, No. 1, 5-56, 2002. The test procedure that was used for measuring Gl in the examples below is as follows. Twelve healthy, medication free subjects ranging from 18 to 60 years of age tested the frozen confections. Test sessions took place in the morning; prior to the session each subject had consumed a similar meal. Each subject received one portion of frozen confection which was consumed with 250 ml water. The control consisted of 25g glucose dissolved in 250 ml water. Each panellist was tested with the glucose standard on three different occasions and each test sample on two different occasions. The study order was F3441(C) randomised to remove any order effects. The subjects' blood glucose levels were measured using a Yellow Springs analyser before consumption, and then every 15 minutes after ingestion of the first spoonful for a period of 2 hours. The blood glucose levels were plotted as a function of time (the blood glucose response curve) and the area under the curve (AUC) was calculated geometrically by applying the trapezium rule, ignoring the area beneath the baseline initial concentration. When a blood glucose value falls below the baseline, only the area above this level is included. The Gl is calculated by dividing the frozen confection AUC by the control glucose AUC for each subject (expressed as a percentage), and then calculating the mean of the values of the 12 subjects. Overrun Overrun is defined by the following equation. It is measured at atmospheric pressure. Sugar alcohols Sugar alcohols are defined as alcohols of mono- and disaccharide sugars as well as polyols based upon hydrolysed starch. They include maltitol, xylitol, sorbitol, arabitol, glycerol, mannitol, lactitol, erythritol, HSH (hydrogenated starch hydrosylate - also known as polyglycitol), isomalt, and palatinose. Non-digestible, non-starch complex saccharides Non-digestible, non-starch saccharides are defined as those saccharides with a metabolisable energy content of less than 3 kcal (12.6 kJ) per g of saccharide which are not derived from starch. Non-digestible, non-starch complex saccharides include inulin, oligofructose, polydextrose and kestose. Starch derivatives Starch derivatives are defined as mono-, oligo- and polysaccharides derived from starch. Starch derivatives include modified starches, maltodextrins, corn syrups, maltotriose, maltose and glucose. F3441(C) Brief Description of the Invention We have now found that low Gl frozen confections which maintain an acceptable texture and level of sweetness can be formulated by using certain sweeteners whilst avoiding others. In particular, we have surprisingly found that frozen confections containing lactose have high Gl values, even though lactose itself has a relatively low Gl. Accordingly, in a first aspect, the present invention provides a frozen confection comprising (by weight of the confection): • from 5 to 15 wt% of a sweetener selected from the group consisting of sugar alcohols, sucrose, fructose, and mixtures thereof; • from 2 to 12 wt% non-digestible, non-starch complex saccharides; • less than 2 wt% starch or starch derivatives; and • less than 3 wt% lactose. Preferably the frozen confection comprises at least 2 wt% milk protein, more preferably in the form of lactose-free whey powder. Preferably the frozen confection comprises at least 2 wt% fat. Preferably the frozen confection comprises less than 2 wt% sucrose. Preferably the sweetener is maltitol and / or fructose. Preferably the frozen confection does not comprise non-saccharide sweetners. Preferably the non-digestible, non-starch complex saccharide is oligofaictose containing 7 or fewer saccharide units. Preferably the frozen confection comprises less than 0.5 wt% lactose. Preferably the frozen confection comprises less than 1.5 wt% galactose. Preferably the frozen confection has an overrun of from 20 to 150%. Preferably the frozen confection has a glycemic index of less than 40. In a related aspect, the present invention provides a process for manufacturing a frozen confection according to the first aspect of the invention, the process comprising the steps of: (a) preparing a mix of ingredients; then (b) pasteurising and optionally homogenising the mix; then (c) freezing and optionally aerating the mix to produce the frozen confection. F3441(C) Detailed Description of the Invention The frozen confection of the invention is preferably an ice cream. Ice cream typically contains, by weight of the composition, 2-20% fat, 2-15% milk protein, 12-20% sweeteners, together with other minor ingredients such as stabilisers, emulsifiers, colours and flavourings. In ice creams or water ices according to the invention, the sugars found in a typical ice cream are replaced with sugar alcohol, fructose and / or sucrose in combination with non-digestible, non-starch complex saccharides, so that the frozen confection has a low glycemic index. In order to provide sweetness and freezing point depression whilst not contributing too greatly to the glycemic index, the frozen confection comprises a sugar alcohol, sucrose, fructose or a mixture thereof in a total amount of at least 5% by weight of the frozen confection, preferably at least 6%, more preferably at least 7% and most preferably at least 8%. To avoid the product being excessively sweet, the frozen confection comprises the sugar alcohol, sucrose, fructose or a mixture thereof in a total amount of at most 15% by weight of the frozen confection, preferably at most 14%, more preferably at most 13%, most preferably at most 12%. Sugar alcohols are suitable for use in low Gl products since they do not cause appreciable increases in blood glucose levels when eaten. Preferred sugar alcohols are maltitol and xylitol. Maltitol is a sugar alcohol based on the disaccharide maltose. It has a high relative sweetness of 0.9 (compared to sucrose). Xylitol is a sugar alcohol based on xylose. It also has a high relative sweetness, i.e. 0.8. Neither maltitol nor xylitol causes off flavours often associated with other polyols such as glycerol or sorbitol. Both maltitol and xylitol have relatively high digestive tolerance compared to other polyols. Fructose has a low Gl value of 20. Sucrose has a moderate effect on blood glucose levels, with a Gl of 60. Surprisingly we have found that sucrose can be used to make a low Gl product, even though it has a moderately high Gl value. However, in order to make a frozen confection having a very low glycemic index, for example less than 30, it is preferable not to use a substantial amount of sucrose, such as less than 2% by weight of the frozen confection. Preferably the sweetener is selected from maltitol and / or fructose. F3441(C) A further advantage of the present invention is that the frozen confection according to the present invention can be made with a very low amount of intensive non-saccharide sweetener. Intensive Non-saccharide sweeteners have relative sweetness, which is higher than 1. Examples of intense sweeteners are aspartame, saccharin, acesulfame K, alitame, thaumatin, cyclamate, glycyrrhizin, stevioside, neohesperidine, sucralose, monellin and neotame. It is nevertheless possible to add intensive non-saccharide sweeteners. Some of the non-saccharide sweeteners have far higher relative sweetness when compared to others. As defined herein, relative sweetness Rj refers to the sweetness of a substance relative to the sweetness of an equivalent weight of sucrose (i.e. sucrose has a relative sweetness of 1). The relative sweetness of the non-saccharide sweeteners is given in the following table. Non-Saccharide Sweetener (i) Relative sweetness (Ri) Aspartame 200 Saccharin 400 Acesulfame K 200 Alitame 2,000 Thaumatin 2,000 Cyclamate 35 Glycyrrhizin 50 Stevioside 100 Neohesperidine 1,500 Sucralose 500 Monellin 2,000 Neotame 10,000 F3441(C) For a mixture of intensive non-saccharide sweeteners, the relative sweetness, R is defined by the following equation: wherein mi is the mass of the intensive non-saccharide sweetener i. In preferred embodiments of the present invention the intensive non-saccharide sweeteners are present in a total amount CT given by the following condition: CT99% pure. Inulin was Raftiline™ supplied by ORAFTI (Tienen, Belgium) and had a moisture content of 3.8 wt%. On a dry basis the inulin consisted of 92 wt% oligofructose and 8 wt% sugars (sucrose, fructose and glucose). Skimmed milk powder contained 50 wt% lactose, 35 wt% protein and 1 wt% milk fat with the remainder being ash and moisture. The low lactose milk protein concentrate was Alaplex 1380 PPV, supplied by Fonterra, and contains less than 0.1 wt% lactose. The emulsifier was Grinsted Mono-Di HP 60 supplied by Danisco (Babard, Denmark) and contained 98 wt% saturated fatty acids. All ingredients except for the oil and emulsifier were combined in an agitated heated mix tank. The oil was warmed to around 60°C and then the emulsifier was added to the oil F3441(C) prior to pouring into the mix tank. Once all of the ingredients were blended together, the mix was subjected to high shear mixing at a temperature of 65°C for 2 minutes. The mix was then passed through an homogeniser at 150 bar and 70°C and then subjected to pasteurisation at 83°C for 20 s before being rapidly cooled to 4°C by passing through a plate heat exchanger. The premix was then aged at 4°C for 5 hours in an agitated tank prior to freezing. Each formulation was frozen using a typical ice cream freezer (scraped surface heat exchanger) operating with an open dasher (series 15), a mix flow rate of 150 litres / hour, an extrusion temperature of -7°C and an overrun of 100%. Directly from the freezer, the ice cream was filled into 250 ml cartons. The cartons were then hardened by blast freezing for 2 hours at -30°C before being transferred to a -25°C store for storage. The glycemic index of the ice creams of examples 1 to 3 were measured by Leatherhead Food International, Leatherhead, Surrey, UK, using the method described above. The results are shown in Table 2. Table 2 Glycemic Index measurements Example 1 2 3 Gl value 20 ±7 23 ±7 37 ±7 Gl rating Low Low Low On tasting, examples 1-4 were found to be firmer and less sweet than a conventional ice cream, but were nonetheless judged to be acceptable products. Thus by carefully selecting the type and amounts of sweeteners, and in particular avoiding starch derivatives and lactose, ice creams with very low glycemic indices and acceptable sweetness and texture were obtained. The various features and embodiments of the present invention, referred to in individual sections above apply, as appropriate, to other sections, mutatis mutandis. Consequently features specified in one section may be combined with features specified in other sections, as appropriate. All publications mentioned in the above specification are herein incorporated by reference. Various modifications and variations of the described methods and products F3441(C) of the invention will be apparent to those skilled in the art without departing from the scope of the invention. Although the invention has been described in connection with specific preferred embodiments, it should be understood that the invention as claimed should not be unduly limited to such specific embodiments. Indeed, various modifications of the described modes for carrying out the invention which are apparent to those skilled in the relevant fields are intended to be within the scope of the following claims. F3441(C) Claims 1. A frozen confection comprising by weight of the confection: • from 5 to 15 wt% of a sweetener selected from the group consisting of sugar alcohols, sucrose, fructose, and mixtures thereof; • from 2 to 12 wt% non-digestible, non-starch complex saccharides; • less than 2 wt% starch or starch derivatives; and • less than 3 wt% lactose. 2. A frozen confection according to claim 1 which comprises at least 2 wt% milk protein. 3. A frozen confection according to claim 2 wherein the milk protein is provided in the form of lactose-free whey powder. 4. A frozen confection according to any of claims 1 to 3 which comprises at least 2 wt% fat. 5. A frozen confection according to any of claims 1 to 4 which comprises less than 2 wt% sucrose. 6. A frozen confection according to any of claims 1 to 5 wherein the sweetener is maltitol and / or fructose. 7. A frozen confection according to any of claims 1 to 6 comprising non-saccharide sweeteners chosen from the group consisting of aspartame, saccharin, acesulfame K, alitame, thaumatin, cyclamate, glycyrrhizin, stevioside, neohesperidine, sucralose, monellin and neotame in an amount of CT