Abstract:
A low-calorie frozen confection is provided which is substantially free from non-saccharide sweeteners. The frozen confection comprises total sugar in an amount of less than 14.5% by weight and digestible complex saccharides in an amount of from 7 to 30% by weight. The total sugar comprises at least 4% fructose by weight of the frozen confection. Also provided is a process for manufacturing the frozen confection.

Description:
TECHNICAL FIELD OF THE INVENTION  
       [0001]     The present invention relates to frozen confections such as ice creams and sorbets. More particularly the present invention relates to low-calorie frozen confections.  
       BACKGROUND OF THE INVENTION  
       [0002]     The incidence of obesity and the number of people considered overweight in countries where a so-called Western diet is adopted has drastically increased over the last decade. Since obesity and being overweight are generally known to be associated with a variety of diseases such as heart disease, type 2 diabetes, hypertension and arthereosclerosis, this increase is a major health concern for the medical world and for individuals alike. Furthermore, being overweight is considered by the majority of the Western population as unattractive.  
         [0003]     This has led to an increasing interest by consumers in their health and has created a demand for products that help to reduce or control daily caloric intake and/or control body weight.  
         [0004]     Frozen confections such as ice creams, sorbets and water ices are popular and convenient foods and there have been many previous attempts to formulate frozen confections having a reduced calorie content whilst retaining their palatability and convenience. For example, U.S. Pat. No. 4,400,405 discloses dietetic frozen food dessert foods which are fat-free and have a low level of calories. Typical of previous attempts to formulate low-calorie frozen confections, the confections disclosed in U.S. Pat. No. 4,400,405 contain large amounts of non-saccharide sweetener (e.g. sorbitol) and/or high levels of sugars.  
         [0005]     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). Unfortunately, however, replacement of the sugars in frozen confections with non-saccharide sweeteners results in products with an artificial or even unpleasant taste and/or aftertaste. Furthermore, certain non-saccharide sweeteners such as sugar alcohols can cause digestive discomfort in some individuals.  
         [0006]     Thus, we have recognised that there is a need for a low-calorie frozen confection which contains a more natural and healthy sweetener system.  
         [0007]     We have found that such a goal can be achieved by providing a frozen confection having a specific saccharide distribution.  
       Tests and Definitions  
       [0008]     Frozen Confection  
         [0009]     As used herein, the term “frozen confection” refers to a sweet-tasting fabricated foodstuff intended for consumption in the frozen state (i.e. under conditions wherein the temperature of the foodstuff is less than 0° C., and preferably under conditions wherein the foodstuff comprises significant amounts of ice). Typical examples of frozen confections include ice creams, water ices and sorbets.  
         [0010]     Sugars  
         [0011]     As used herein the term “sugars” refers exclusively to digestible mono- and di-saccharides. The total sugar content of a frozen confection is thus the sum of all of the digestible mono- and di-saccharides present within the frozen confection, including any lactose from milk solids and any sugars from fruits.  
         [0012]     Complex Saccharides  
         [0013]     As used herein, the term “complex saccharide” refers to oligosaccharides and polysaccharides with a degree of polymerisation (DP) of at least three.  
         [0014]     Digestible and Non-Digestible Saccharides  
         [0015]     Digestible saccharides are defined as those saccharides with a metabolisable energy content of at least 3 kcal (12.6 kJ) per g of saccharide. Digestible complex saccharides are usually derived from starch and/or comprise alpha glycosidic linkages.  
         [0016]     Non-digestible saccharides are defined as those saccharides with a metabolisable energy content of less than 3 kcal (12.6 kJ) per g of saccharide. Common non-digestible saccharides are non-starch complex saccharides but others include resistant starches and non-digestible di-saccharides.  
         [0017]     Non-Saccharide Sweetener  
         [0018]     Non-saccharide sweeteners as defined herein consist of: 
        The intense sweeteners aspartame, saccharin, acesulfame K, alitame, thaumatin, cyclamate, glycyrrhizin, stevioside, neohesperidine, sucralose, monellin and neotame; and     The sugar alcohols HSH (hydrogenated starch hydrosylate—also known as polyglycitol), eythritol, arabitol, glycerol, xylitol, sorbitol, mannitol, lactitol, maltitol, isomalt, and palatinit.        
 
         [0021]     Relative Sweetness  
         [0022]     As defined herein, relative sweetness, R, 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 Table 1.  
                                         TABLE 1                                   Non-Saccharide Sweetener (i)   Relative sweetness (R i )                                        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           HSH   0.7           Erythritol   0.7           Arabitol   0.5           Glycerol   0.8           Xylitol   1.0           Sorbitol   0.6           Mannitol   0.6           Lactitol   0.4           Maltitol   0.8           Isomalt   0.6           Palatinit   0.5                      
 
         [0023]     For a mixture of non-saccharide sweeteners, the relative sweetness, R, is defined by Equation 1:  
               R   =         ∑   i     ⁢       R   i     ⁢     m   i             ∑   i     ⁢     m   i           ,           (   1   )             
 
 wherein m i  is the mass of non-saccharide sweetener i. 
 
         [0024]     Total Energy Content  
         [0025]     The total energy content (E) of a frozen confection is defined as the sum of the metabolizable energy of the ingredients present within 100 g of the frozen confection. It is calculated using Equation 2:  
               E   =       ∑   j     ⁢       f   j     ⁢     c   j           ,           (   2   )             
 
 wherein c j  is the mass of ingredient j in 100 g of the confection and f j  is the calorie conversion factor for the ingredient j. 
 
         [0026]     For digestible saccharides and proteins, f j  is typically 4.0 kcal (16.7 kJ) per g. For fats, f j  is 9.0 kcal (37.7 kJ) per g.  
         [0027]     Calorie conversion factors are readily available from ingredient manufacturers. Alternatively, the factors may be determined from analysis and comparison of the composition and heats of combustion of dietary material with those of excreted material (see D.A.T. Southgate and J.V.G.A. Durnin, “Calorie conversion factors. An experimental reassessment of the factors used in the calculation of the energy value of human diets.”,  British Journal of Nutrition,  1970, 24, pp. 517-535).  
         [0028]     Overrun  
         [0029]     Overrun is defined by Equation 3:  
             Overrun   =                 volume   ⁢           ⁢   of   ⁢           ⁢   frozen   ⁢           ⁢   aerated   ⁢           ⁢   product     -               volume   ⁢           ⁢   of   ⁢           ⁢   premix   ⁢           ⁢   at   ⁢           ⁢   ambient   ⁢           ⁢   temp             volume   ⁢           ⁢   of   ⁢           ⁢   premix   ⁢           ⁢   at   ⁢           ⁢   ambient   ⁢           ⁢   temp       ×   100.             (   3   )             
 
 It is measured at atmospheric pressure. 
 
       BRIEF DESCRIPTION OF THE INVENTION  
       [0030]     We have found that low-calorie frozen confections with low levels of sugars but with excellent palatability can be formulated even without the use of non-saccharide sweeteners by employing a sweetener system comprising at least 4% fructose and digestible complex saccharides in specific amounts.  
         [0031]     Thus, in a first aspect, the present invention provides a frozen confection having a total energy content of less than 160 kcal (669 kJ) per 100 g of frozen confection and being substantially free from non-saccharide sweeteners. The frozen confection comprises: 
        total sugar in an amount of less than 14.5% by weight of the frozen confection, the total sugar comprising at least 4% fructose by weight of the frozen confection, and     digestible complex saccharides in an amount of from 7 to 30% by weight of the frozen confection.        
 
         [0034]     By “substantially free from non-saccharide sweetneners” is meant that the frozen confection contains less non-saccharide sweetener than would be required to give a sweetness equivalent to 0.5% (w/w) sucrose, i.e., the frozen confection comprises non-saccharide sweeteners in a total amount C T  given by the following condition: 
 
 C   T   &lt;X/R,  
 
 wherein X is 0.5% (w/w) and R is the relative sweetness of the non-saccharide sweeteners. Preferably, X is 0.1% (w/w), more preferably 0.01% (w/w). 
 
         [0035]     Fructose has a high relative sweetness and it has been found that at levels of at least 4% (w/w), preferably at least 4.5%, more preferably at least 4.75%, that the fructose (in combination with other saccharides) provides sufficient sweetness to negate the need for non-saccharide sweeteners.  
         [0036]     Recent research has highlighted potential adverse effects of a high fructose intake on cardiovascular risk factors owing to the way in which fructose is metabolised. Therefore it is preferred that there is less than 9% fructose by weight of the frozen confection, more preferably less than 8%, even more preferably less than 7.5%.  
         [0037]     In order to maximise the nutritional quality of the confection it is necessary to limit the amount of sugars to less than 14.5% (w/w). It is particularly preferred that the total sugars are present in an amount of less than 14%, more preferably less than 12%. A certain level of total sugars is desirable, however, in order to provide freezing point depression and contribute to the sweetness of the confection. Thus it is preferred that the frozen confection comprises at least 7% total sugars, more preferably at least 8% and most preferably at least 9% by weight of the frozen confection.  
         [0038]     As well as fructose, the total sugar may comprise one or more monosaccharides such as glucose (dextrose) or galactose, and/or one or more disaccharides such as lactose, maltose or sucrose. It is particularly preferred that the total sugar comprises lactose because lactose provides excellent freezing point depression without unduly contributing to sweetness. Thus it is preferred that the total sugar comprises at least 0.5% lactose by weight of the frozen confection, preferably at least 2% and more preferably at least 3%. Too much lactose should be avoided however owing to its propensity to crystallise from solution at high concentration. Thus it is preferred that the lactose content is limited to less than 8% by weight of the frozen confection, more preferably less than 7% and most preferably less than 6.5%.  
         [0039]     In order to compensate for the relatively low levels of sugars employed, it is necessary that the frozen confection comprises digestible complex saccharides in an amount of at least 7% by weight of the frozen confection, preferably at least 8.5% and most preferably at least 10%. To avoid the confection becoming overly hard, however, it is necessary that the digestible complex saccharide is used in an amount of less than 30% by weight of the frozen confection, preferably less than 25% and most preferably less than 20%.  
         [0040]     The complex saccharide can cause the ice cream to become hard and unpalatable owing to its relatively high molecular weight. Thus, although the digestible complex saccharide may be sourced from any suitable material, such as maltodextrin, starch or glucose syrup (also known as “corn syrup”), it is preferred that the digestible complex saccharide is substantially sourced from a glucose syrup having a DE greater than 20. Particularly preferred are glucose syrups having a DE in the range 22 to 45 DE as they contain complex saccharides of not too high a molecular weight whilst not contributing large amounts of sugars. Most preferred are glucose syrups having a DE in the range 22 to 34. Most convenient are glucose syrups comprising sugars in an amount of from 8 to 35% by dry weight of the glucose syrup, preferably from 10 to 25%.  
         [0041]     It is preferable that the frozen confection contains fat in order to provide a carrier for fat-soluble flavours and to enhance the stability and processability of the confection. Thus it is preferable that the confection comprises at least 0.5% fat, more preferably at least 1% and most preferably at least 1.5%. The fat content should not be too high, however, otherwise the nutritional balance of the confection becomes unhealthy. Thus it is preferred that the confection comprises less than 7% fat by weight of the frozen confection, more preferably less than 6% and most preferably less than 5%.  
         [0042]     As used herein, the term “fat” refers to both saturated and unsaturated fatty acids. The fatty acids are usually present in the form of esters (e.g. mono-/di-/tri-glycerides). In order for the fat to contribute optimally to the stability and processability of the confection, it is preferred that the confection contains some saturated fat. In particular it is preferred that the fat comprises at least 10% saturated fatty acids by weight of the fat, more preferably at least 20%. The saturated fat content may also be limited in order to increase the nutritional value of the confection. Thus in a preferred embodiment, the fat comprises less than 55% saturated fatty acids by weight of the fat, more preferably less than 50%, and most preferably less than 40%.  
         [0043]     Suitable fats for use in the present invention include animal fats (such as butterfat) and vegetable oils (such as coconut oil, palm oil, sunflower oil, safflower oil, rapeseed oil, and soya oil) and mixtures thereof.  
         [0044]     The frozen confection may also contain protein. Suitable proteins for use in the present invention include animal proteins such as milk proteins, egg proteins and gelatin as well as vegetable proteins such as soya proteins. Particularly preferred are milk proteins owing to their superior flavour, heat stability and surface activity. Suitable sources of milk protein include milk, concentrated milk, milk powders, whey, whey powders and whey protein concentrates/isolates. In order to aid in emulsification and/or aeration during manufacture of the frozen confection it is preferable that the protein content is greater than 1% by weight of the frozen confection, more preferably greater than 2%. In order to allow for destabilisation of the fat during freezing of the frozen confection and/or to prevent the texture of the confection from becoming chalky, it is also preferable that the protein content is less than 8%, more preferably less than 6% by weight of the frozen confection.  
         [0045]     In a particularly preferred embodiment of the invention, the frozen confection further comprises non-digestible saccharides, as such materials can contribute to the freezing point depression and/or body of the confection without increasing the energy content of the confection or contributing to sweetness. Preferably the non-digestible saccharide is employed in an amount of at least 4% by weight of the frozen confection, preferably at least 5% and most preferably at least 7.5%. In order to avoid undue freezing point depression and/or undue hardness it is preferred that the non-digestible saccharide is present in an amount of less than 15% by weight of the frozen confection, preferably less than 10% and most preferably less than 9.0%.  
         [0046]     Suitable non-digestible saccharides include oligofructose, inulin, polydextrose, resistant starch and mixtures thereof.  
         [0047]     Polydextrose is a randomly bonded condensation polymer of D-glucose with some bound sorbitol and citric acid. The 1,6-glycosidic linkage predominates in the polymer. Polydextrose is resistant to digestion in the human small intestinal tract and has a metabolisable energy content (calorie conversion factor) of 1.0 kcal (4.2 kJ) g −1 . It is available from the Danisco company under the trade name Litesse™. Polydextrose has a relatively high molecular weight of around 2500.  
         [0048]     Resistant starches are food starches or starch derivatives which are not digestible by the human body. There are four main groups of resistant starches: RS1, RS2, RS3 and RS4. RS1 is physically inaccessible starch, e.g. trapped in seeds. RS2 starch is granular starch. Examples include banana, high amylose starches. RS3 starch is a highly retrograded starch, e.g. extruded cereals. RS4 is chemically modified starch. Resistant starches have a metabolisable energy content (calorie conversion factor) of around 1.6 kcal (6.7 kJ) g −1 . Resistant starches are available commercially from National Starch under the trade names Novelose™ and Hi-maize™.  
         [0049]     Oligofructose and inulin are both available from the ORAFTI company under the trade names Raftlilose™ and Raftiline™, respectively. Inulin and oligofructose are composed of linear chains of fructose units linked by β(2-1) bonds and often terminated by a glucose unit. Inulin contains chains with up to 60 fructose units. Oligofructose has between 2 and 7 fructose units. Oligofructose is obtained from inulin by partial enzymatic hydrolysis. Inulin has a metabolisable energy content (calorie conversion factor) of 1.2 kcal (5.0 kJ) g −1 , whilst oligfructose has a metabolisable energy content (calorie conversion factor) of 2 kcal (8.4 kJ) g −1 . Despite its higher energy content, oligofructose is the preferred source of non-digestible saccharide for use in the present invention owing to its low molecular weight and therefore high freezing point depression power.  
         [0050]     Frozen confections according to the present invention preferably contain ice. Thus it is preferred that the frozen confections contain at least 50% water by weight of the frozen confection, more preferably at least 61% and most preferably at least 65%.  
         [0051]     According to a preferred embodiment of the invention, the frozen confection is aerated. The overrun may range from 50 to 150%, preferably 70 to 130%.  
         [0052]     The frozen confections may also comprise a stabiliser. Suitable stabilisers include one or more of tara gum, guar gum, locust been gum, carrageenan, gelatin, alginate, carboxymethyl cellulose, xanthan and pectin.  
         [0053]     The frozen confections provided by the present invention afford consumers the everyday enjoyment of a popular food without delivering too high an energy content. Preferably the total energy content of the confection is less than 150 kcal (628 kJ) per 100 g of frozen confection, most preferably in the range 90 to 145 kcal (377 to 607 kJ) per 100 g of frozen confection.  
         [0054]     The frozen confections of this invention may also suitably provide a low calorie base for delivering nutritional actives. Thus in a preferred embodiment the frozen confection is fortified with one or more nutritional actives. The nutritional actives may be a mineral, a vitamin, a pro-biotic, a pre-biotic, an antioxidant, an essential oil, a plant sterol, an appetite suppressant, or a bioactive peptide.  
         [0055]     The frozen confections of the present invention are particularly suitable for storage and consumption from the domestic deep freeze. Thus it is preferred that the temperature of the frozen confection is below −12° C., more preferably below −14° C. and most preferably in the range −25 to −16° C.  
         [0056]     The frozen confections may be manufactured by any suitable process. However, in a further aspect of the invention there is provided a process for manufacturing the frozen confection, the process comprising the steps of: 
        (a) preparing a premix of ingredients; then     (b) pasteurising and homogenising the premix; then     (c) freezing and optionally aerating the premix to form a soft ice; and then.     (d) hardening the soft ice to produce the frozen confection.        
 
         [0061]     Typically the extrusion temperature in step (c) will be in the range −3° C. to −10° C., preferably in the range −5° C. to −9° C.  
         [0062]     “Hardening” as used herein means cooling the soft ice until it is stiff enough to hold its own shape. It is a well-known term in the art and typical processes for hardening are described in “Ice Cream”, 4th Edn, (W. S. Arbuckle, 1986, van Nostrand Renhold Co Inc, NY) at page 262. Typically the soft ice will be hardened at a temperature in the range −20 to −40° C., preferably −25 to −35° C. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0063]     The invention will now be further described by reference to the following non-limiting examples.  
       EXAMPLE 1  
       [0064]     This example demonstrates two frozen confections and a process according to the invention.  
         [0065]     Materials  
         [0066]     The frozen confections were formulated using the following materials: 
        Skimmed milk powder (SMP) was supplied by Meadow Foods (York, UK) and contained 50% (w/w) lactose, 35% (w/w) protein and 1% (w/w) milk fat with the remainder being ash and moisture.     Whey powder was “Avonol 600” supplied by Glanbia (Harefield, UK) and contained 50% (w/w) lactose, 35% (w/w) protein and 3% milk fat with the remainder being ash and moisture.     Fructose was pure and crystalline and supplied by Tate and Lyle (London, UK).     Guar gum was supplied by Willy Benecke (Hamburg, Germany) and had a moisture content of 14%.     Carrageenan was Genulacta™ L100 supplied by CP Kelco (Lille Svensved, Denmark) and had a moisture content of 11%.     Emulsifier was Grinsted™ Mono-Di HP 60 supplied by Danisco (Babard, Denmark) and contained 98% (w/w) saturated fatty acids.     Locust Bean Gum (LBG) was Viscogum FA supplied by Degussa Texturant Systems (France) and had a moisture content of less than 10%.     Palm oil was supplied by Cargill Brocklebank (Merseyside, UK) and had a saturated fatty acid content of 51%.     Glucose syrup was C*Pur™ 01934, supplied by Cerestar (France) and had a DE of 38 and a moisture content of 3% (w/w). On a dry basis the glucose syrup solids consisted of 34% (w/w) sugars (consisting of 1% dextrose and 33% maltose) and 66% (w/w) digestible complex saccharides (consisting of 23% maltotriose and 43% higher saccharides).        
 
         [0076]     Formulations  
         [0077]     The two formulations along with their properties are given in Table 2.  
                                                       TABLE 2                                       Formulation                1   2                            SMP (% w/w)   4.31   4.31           Whey Powder (% w/w)   5.00   5.00           Glucose Syrup (% w/w)   11.25   14.25           Emulsifier (% w/w)   0.40   0.40           Palm Oil (% w/w)   4.90   4.90           Flavour (% w/w)   0.20   0.20           Fructose (% w/w)   5.25   5.00           Guar (% w/w)   0.11   0.11           LBG (% w/w)   0.25   0.25           Carrageenan (% w/w)   0.04   0.04           Water   68.29   65.54           E (kcal/100 g)   146   156           E (kJ/100 g)   611   653           Total sugars (% w/w)   13.6   14.4           Total Fructose (% w/w)   5.3   .5.0           Digestible complex saccharides (% w/w)   7.2   9.1           Non-digestible saccharides (% w/w)   0.3   0.3                      
 
         [0078]     Process  
         [0079]     All ingredients except from the oil and emulsifier were combined in an agitated heated mix tank. The oil was warmed to around 60° C. and then the emulsifier added to the liquid fat 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.  
         [0080]     The premix was then passed through a 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.  
         [0081]     Each formulation was frozen using a typical ice cream freezer (scraped surface heat exchanger, SSHE) operating with an open dasher (series 80), a mix flow rate of 150 l/hour, an extrusion temperature of −7° C. and an overrun (at atmospheric pressure) 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.  
         [0082]     The ice creams were stored at −25° C. for 3 weeks and then tempered at −18° C. for 24 hours before consumption.  
       EXAMPLE 2  
       [0083]     This example demonstrates a further confection according to the invention which comprises significant levels of non-digestible saccharides.  
         [0084]     Materials  
         [0085]     The frozen confections were formulated using the same materials as in Example 1 with the exception of the following: 
        Coconut oil was supplied by Van den Bergh Oils (Purfleet, UK) and had a saturated fatty acid content of 90%.     Glucose syrup was C*Dry™ GL 01924, supplied by Cerestar (France) and had a DE of 28 and a moisture content of 4% (w/w). On a dry basis the glucose syrup solids consisted of 14% (w/w) sugars (consisting of 3% dextrose and 11% maltose) and 86% (w/w) digestible complex saccharides (consisting of 16.5% maltotriose and 69.5% higher saccharides).     Oligofructose was Raftilose™ P95 supplied by ORAFTI (Tienen, Belgium) and had a moisture content of 3% (w/w). On a dry basis the Raftilose™ consisted of 95% (w/w) oligofructose and 5% (w/w) sugars (consisting of 3% sucrose, 1% fructose and 1% glucose).        
 
         [0089]     Formulation  
         [0090]     The formulation along with its properties are given in Table 3.  
                                     TABLE 3                                   Formulation 3                                        SMP   7.00           Glucose Syrup   14.30           Emulsifier   0.30           Coconut Oil   3.00           Flavour   0.01           Fructose   6.00           Guar   0.10           LBG   0.15           Carrageenan   0.02           Oligofructose   8.30           Water   60.82           E (kcal/100 g)   135           E (kJ/100 g)   565           Total sugars (% w/w)   11.8           Total Fructose (% w/w)   6.1           Digestible complex saccharides (% w/w)   11.8           Non-digestible saccharides (% w/w)   7.9                      
 
         [0091]     Process  
         [0092]     The formulation is processed as in Example 1.