The present invention relates to an aerated food composition comprising a high- melting fat, a medium-melting fat, and a low-melting fat. A further aspect of the invention is a method of manufacturing an aerated food composition comprising letting the composition perform a first crystallization event; aerating the composition; and controlling the temperature of the aerated composition to allow a second crystallization event in the composition.

Background of the Invention Aerated compositions are of particular interest to the food industry, having the potential to provide new textures and sensory properties. There is increasing concern about the amount of fat consumed in people's diet. Foaming fat-containing materials provides a method to maintain product volume whilst reducing the fat content.

The major difficulty in generating stable foam structures within fat-based systems as compared to water-based systems lies in the lack of suitable surfactants for forming stable interfaces between air and lipid. Those surfactants which have been proposed may not be suitable for stabilizing edible foams due to toxicity or unpleasant taste. As a consequence, the most common approach for obtaining stable foams in a fat-based matrix is by forming a rigid network in the bulk material, for example by forming a rigid network of crystals in a liquid fat-continuous phase or by rapidly cooling the lipid so as to solidify the bulk material. However, both of these approaches lead to constraints when processing the foam. Having a rigid network in the fat-continuous phase affects the ability of the foam to be pumped, deposited, or mixed with other components without destroying the stabilizing network leading to coalescence of bubbles. A foam stabilized by solidifying the bulk is generally unstable before solidification and so can only be maintained as a foam for a short period and cannot be subject to substantial shear forces during processing.

Aerated fat-based food compositions typically use a high proportion of harder fats to rapidly crystallize and so stabilize the aerated structure after processing, preventing a loss of volume during the prolonged fat crystallization process which, for softer fats, may continue long after the product has been wrapped. These harder fats have high saturated fatty acid (SFA) contents. Consumption of saturated fatty acids have been linked to increased levels of LDL cholesterol in the blood and heart diseases and so it would be advantageous to be able to reduce the consumption of saturated fatty acids. Mixing solid inclusions such as raisins or nut pieces into aerated food compositions presents a challenge. As the inclusions are mixed into the composition they tend to break down the foam or, when inclusions are present before aeration, they reduce the effectiveness of foam generation. One way around this difficulty is to aerate by applying a vacuum as described in US2082313, but continuous vacuum processes are complex to engineer and costly to maintain.

The challenges of producing fats which have the appropriate physical properties to be satisfactorily aerated has led many suppliers to offer interesterified fats for this purpose. Interesterification of vegetable oils may enhance the amount of saturated fatty acids at the 2-position. Fatty acids at the 2-position are biologically different from fatty acids at the 1 and 3 position because they are handled differently during digestion and metabolism. Some consumers are concerned that this may have a negative health impact, and would prefer to consume fats in their "natural" configuration.

Hence, there is a need in the industry to find better solutions to produce stable aerated fat-continuous food compositions, in particular edible fat foams which taste good and are made from natural ingredients. It would furthermore be advantageous to find solutions which do not require the use of interesterified fats. An object of the present invention is to improve the state of the art and to provide an improved solution to overcome at least some of the inconveniences described above or at least to provide a useful alternative. Any reference to prior art documents in this specification is not to be considered an admission that such prior art is widely known or forms part of the common general knowledge in the field. As used in this specification, the words "comprises", "comprising", and similar words, are not to be interpreted in an exclusive or exhaustive sense. In other words, they are intended to mean "including, but not limited to". The object of the present invention is achieved by the subject matter of the independent claims. The dependent claims further develop the idea of the present invention. Summary of the invention

Accordingly, the present invention provides in a first aspect an aerated food composition having a continuous fat phase, the composition comprising between 35 and 60 wt.% of non-interesterified fat and between 40 and 65 wt.% of non-fat solids having a particle size distribution D90 of less than 100 μηη, the non-interesterified fat comprising a high-melting fat, a medium-melting fat, and a low-melting fat, wherein the aerated composition comprises, on a total fat basis, less than 45 wt.% of saturated fatty acids, between 9 and 60 wt.% of monounsaturated fatty acid, and less than 30 wt.% of polyunsaturated fatty acid, and wherein the high-melting fat has a melting point between 35 °C and 80 °C, the medium-melting fat has a melting point between 15 °C and 30 °C and the low-melting fat has a melting point between -50 °C and 5 °C. In a second aspect, the invention relates to a method of manufacturing the aerated food composition of the first aspect, the method comprising the steps; providing a composition comprising the non-fat solids and the non-interesterified fat, the continuous fat phase comprised within the composition being liquid; letting the composition perform a first crystallization event; aerating the composition; and controlling the temperature of the aerated composition to allow a second crystallization event in the composition. It has been surprisingly found by the inventors that a food composition comprising a high-melting fat, a medium-melting fat, and a low-melting fat provides excellent aeration properties at low levels of saturated fat. The resulting fat-phase crystallizes at two distinct temperatures during processing, leaving the low-melting fat in the liquid state. By initially cooling the liquid composition to a temperature at which a first fat crystallization event occurs and then whipping the composition, a stable foam is produced. The gas bubbles in the foam are found to be coated in fat crystals. The crystals jam together around the bubble, leading to mechanical stability and resisting bubble shrinkage. At this stage, the bulk remains soft, e.g. there is no rigid network of crystals in-between the bubbles. This allows the foam to be processed, for example pumped, deposited or mixed with inclusions, while the crystals wrapping the gas bubbles prevent significant loss of foam volume. Once the foam has been formed as required, for example deposited into moulds, it is then cooled to temperature at which a second crystallization event occurs. This second crystallization event builds a network in the fat phase, surprisingly developing a desired texture and stability despite the presence of un-solidified fat from the low-melting component. This low-melting component reduces the overall level of saturated fats in the composition.

Brief Description of the Drawings

Figure 1 shows optical micrographs of aerated foams of compositions C-E, just after aeration (left column) and fat crystals coating the interfaces between bubbles in aerated foams diluted with oil (right column)

Figure 2 shows stability of aerated foam structures of compositions C-E, deposited without inclusions (left column), and with 10% fruit inclusions of 3 mm size (right column) after overnight storage at different temperatures (20, 28, 30, 34 °C) Figure 3 shows optical micrographs of aerated filling recipe 2, just after aeration (left) and fat crystals coating the interfaces between bubbles in aerated foams diluted with oil (right) Figure 4 shows 1 week old aerated foams of filling recipes 1-4 stored at room temperature (approx. 20°C)

Figure 5 shows a differential scanning calorimeter melting thermogram of 1 week old aerated foams of filling recipes 1-4 stored at room temperature (approx. 20°C) Figure 6 shows aerated (a) Filling recipe 1 and (b) Filling recipe 3 with 10 wt.% fruit inclusions of 3 mm size in chocolate tablets stored at room temperature (approx. 20°C)

Detailed Description of the invention

Consequently the present invention relates in part to an aerated food composition having a continuous fat phase, the composition comprising between 35 and 60 wt.% (for example between 40 and 55 wt.%) of non-interesterified fat and between 40 and 65 wt.% (for example between 45 and 60 wt.%) of non-fat solids having a particle size distribution D90 of less than 100 μηη (for example less than 50 μηη), the non- interesterified fat comprising (for example consisting of) a high-melting fat, a medium- melting fat, and a low-melting fat, wherein the aerated composition comprises, on a total fat basis, less than 45 wt.% (for example less than 40 wt.%) of saturated fatty acids, between 9 and 60 wt.% (for example between 15 and 50 wt.%) of monounsaturated fatty acid, and less than 30 wt.% of polyunsaturated fatty acid, and wherein the high-melting fat has a melting point between 35 °C and 80 °C (for example between 40 °C and 50 °C), the medium-melting fat has a melting point between 15 °C and 30 °C (for example between 18 °C and 25 °C) and the low-melting fat has a melting point between -50 °C and 5 °C.

The non-fat solids may be provided in the form of materials selected from the group consisting of sugar, nuts, cocoa, milk powder and combinations of these. The non-fat solids may be provided at a larger particle size and then dispersed in at least a part of the non-interesterified fat before being ground to the desired particle size distribution. A D90 value is the diameter below which lie 90% of the particles in the distribution. The particle size may be measured by laser light scattering.

According to the present invention, the composition may comprise 0.1 to 2 wt. % of emulsifiers, for example emulsifiers selected from sunflower lecithin, soya lecithin, polyglycerol polyricinoleate (PGPR; E476), ammonium phosphatide (YN; E442) or a combination thereof. The composition may comprise lecithin but no other emulsifier.

In the context of the present invention, the term fat refers to triglycerides. Fats are the chief component of animal adipose tissue and many plant seeds. Fats which are generally encountered in their liquid form are commonly referred to as oils. In the present invention the terms oils and fats are interchangeable. The melting point of a fat may for example be the temperature at which it has a 1 % solid fat content as measured by pulsed NMR.

Interesterified fat is a type of fat where the fatty acid residues have been moved from one triglyceride molecule to another, or from one position on the glycerol backbone to another. Saturated fatty acids are not common in the central "2 position" of natural triglycerides. They are more common in interesterified fats, where the interesterification process has re-arranged the positions of the fatty acids. The fat phase of the composition of the invention may have a ratio of SSU triglycerides to SUS triglycerides of less than 0.1, wherein S indicates a saturated fatty acid residue with 16 to 24 carbon atoms and U indicates an unsaturated fatty acid residue with 18 carbon atoms. The description SSU indicates a triglyceride with S in the 1 position, S in the 2 position and U in the 3 position of the glycerol backbone. (It should be noted that SSU and USS are equivalent in this context as the 1 and 3 positions are interchangeable.) Similarly SUS triglycerides have S in the 1 position, U in the 2 position and S in the 3 position of the glycerol backbone.

The aerated food composition of the invention may have a soft texture at 20 °C. Soft textured aerated food compositions include confectionery fillings and spreads. Spreads and fillings may be very soft, for example having a maximum penetration force of between 10 and 60 g at 20 °C. Fillings have a wider range of texture and may have a maximum penetration force of between 10 and 1500 g at 20 °C. A material having a soft texture may be considered to be a material having a maximum penetration force of less than 1500 g at 20 °C, for example less than 1000 g at 20 °C, for further example less than 500 g, for further example less than 100 g, for further example less than 60 g. The maximum penetration force may for example be measured using a 60° conical probe. Conical probes are suitable for soft materials. A conical probe may cause a hard material to fracture before completing the measurement. Hard materials such as chocolate would generally have a penetration force above 3000 g at 20 °C. Cylindrical probes are more suitable for hard materials.

The term "aerated" is used to refer to a foam, in other words a dispersion of a gas in a solid or liquid medium. The gas may be any gas commonly used for foam generation such as C0 ₂ , N ₂ or N ₂ 0, but typically the gas is air. The aerated food composition may have a porosity of between 1 and 80 %, for example between 10 and 75 %. The term porosity refers to the fraction of the volume of gas-filled voids over the total volume, as a percentage between 0 and 100 %.

The aerated composition may comprise water, for example water may be emulsified into the continuous fat phase. The aerated food composition of the invention may have a low moisture content, for example the composition may contain less than 5 % water by weight, for example less than 2.5 % water by weight. It should be noted that the aerated composition of the present invention can be formed without moisture, for example without the use of surfactants in water or the formation of an emulsion containing water. Food ingredients that are completely free from moisture are rare, but the composition of the invention may be essentially free from water.

The fat phase of the aerated food composition of the invention may crystallize at two distinct temperatures between 50 °C and 0 °C. This two-step crystallization allows the separation during processing of the stabilization of gas bubbles (after at least a portion of the high-melting fat crystallizes) and the formation of a network in the bulk (after at least a portion of the medium-melting fat crystallizes). The fat component of the aerated food composition of the invention may have a solid fat content between 5 and 35 % at 20 °C and a solid fat content at 10 °C increased by between 10 and 20 % from the value at 20 °C. For example the fat component may have a solid fat content of 10 % at 20 °C and solid fat content at 10 °C of 25 %, this being increased by 15 %. The solid fat content may be measured by pulsed NMR, for example according to the lUPAC Method 2.150 (tempered). The solid fat content may also be measured by differential scanning calorimetry.

The aerated food composition may comprise gas bubbles whose surface is wrapped by glyceride crystals. Such crystal-wrapped bubbles being obtainable by cooling the composition such that at least a portion of the high-melting fat crystallizes (for example forming a gel) and then whipping the composition. Particularly stable assemblies of crystal-wrapped bubbles can be obtained by using a process of prolonged and intensive whipping. The composition of the invention may additionally comprise glycerides selected from the group consisting of monoglycerides, diglycerides, esters of monoglycerides, esters of diglycerides and combinations of these. For example glycerides with a melting point between 35 °C and 60 °C, for example between 40 °C and 50 °C. These glycerides can assist in the formation of crystal-wrapped bubbles. Under conditions at which the fat phase has a solid fat content between 0.1 and 80% (e.g. between 5 and 20%), the composition of the invention may comprise gas bubbles having at least 50 % of their surface occupied by crystals, the crystals comprising a glyceride selected from the group consisting of monoglycerides, diglycerides, triglycerides, esters of monoglycerides, esters of diglycerides and combinations of these. The crystals may comprise (for example consist of) triglycerides.

A gel is a non-fluid network characterised by a continuous liquid throughout its whole volume. A gel may be defined by its rheology. For example at a frequency of 1 Hz, the measured linear shear elastic modulus G' of a gel may be greater than 10 Pa and the viscous modulus G" may be less than G'. Gels most suitable for foam generation have a linear shear elastic modulus G' initially in the range 10 ² - 10 ⁷ Pa at 1 Hz, for example a linear shear elastic modulus G' initially in the range 10 ² - 10 ⁶ Pa at 1 Hz, for further example a linear shear elastic modulus G' initially in the range 10 ³ - 10 ⁶ Pa at 1 Hz.

The percentage of the gas bubbles' surface occupied by crystals may be measured using microscopy (for example optical and/or confocal microscopy), coupled with suitable image analysis techniques. With a high level of surface coverage it may be immediately obvious after inspection by microscopy that at least 50 % of the surface of the gas bubbles is occupied by crystals.

The crystals occupying at least 50 % of the surface of the gas bubbles jam together, resisting any shrinkage of the bubbles and providing a stable, flowable foam when the continuous phase is fluid, such as when the fat phase has a solid fat content between 0.1 and 80 %. The crystals occupying at least 50 % of the surface of the gas bubbles may cause the bubbles to have a non-relaxing shape when the foams are diluted with oil. The crystals comprising a glyceride occupying the surface of the gas bubbles may form layers having an average thickness below 5 μηη .

In the context of the present invention the term flowable foam refers to a foam which can be processed in pumping or stirring units using typical food process equipment without undergoing obvious structural coarsening or collapse. The flowable foam may be flowable under gravity after stirring (for example at 20 °C).

The aerated food composition of the invention may comprise gas bubbles having their surface occupied by glyceride crystals, for example triglyceride crystals, such that their surface density is at least 15 mg.nr ² , for example at least at least 25 mg.nr ² , for example at least 50 mg.nr ² , for further example at least at least 200 mg.nr ² . The high-melting fat comprised within the aerated food composition of the invention may be present at a level of between 10 and 30 wt.% of the total fat. The medium- melting fat comprised within the aerated food composition of the invention may be present at a level of between 35 and 75 wt.% of the total fat. The low-melting fat comprised within the aerated food composition of the invention may be present at a level of between 15 and 35 wt.% of the total fat. Such quantities of the three different melting-point fats provide the desired textural and processing characteristics of the aerated food composition.

The high-melting fat comprised within the aerated food composition of the invention may have a saturated fatty acid content greater than 58 %. The medium-melting fat comprised within the aerated food composition of the invention may have a saturated fatty acid content of between 35 and 55 %. The low melting fat comprised within the aerated food composition of the invention may have a saturated fatty acid content of below 20%. The overall saturated fatty acid content of the aerated food composition may be below 45 %, on a total fat basis.

The high melting fat comprised within the aerated food composition of the invention may be selected from the group consisting of stearin or mid-fractions of shea butter, kokum butter, sal butter, cocoa butter, palm oil and algal oil and combinations of these. In addition to stearin or mid-fractions of cocoa butter, the high melting fat may be a naturally hard cocoa butter such as known to be produced from cocoa grown in Malaysia. The high melting fat comprised within the aerated food composition of the invention may for example be selected from the group consisting of stearin or mid- fractions of shea butter, kokum butter, sal butter, palm oil and combinations of these. The medium-melting fat comprised within the aerated food composition of the invention may be selected from the group consisting of soft olein fractions of palm oil, shea butter, kokum butter, sal butter, cocoa butter, algal oil, and combinations of these. The low melting fat comprised within the aerated food composition of the invention may be selected from the group consisting of high oleic sunflower oil, high oleic safflower oil, high oleic soybean oil, high oleic rapeseed oil such as high oleic canola oil, high oleic algal oil, olive oil, macademia nut oil, hazelnut oil, avocado oil, sunflower oil, rapeseed oil, soybean oil, grape-seed oil, cotton-seed oil, corn oil and combinations of these.

Good results are obtained using a fat phase having high levels of triglycerides with saturated fatty acids in the 1 and 3 position. The fat phase of the aerated food composition of the invention may comprise 0.5 to 1.5 wt.% SSS, 2.0 to 3.5 wt.% SSU, more than 40 wt.% SUS, between 20 and 35 wt.% SUU and between 15 and 35 wt.% UUU, wherein S indicates a saturated fatty acid residue with 16 to 24 carbon atoms (C16:0 - C24:0) and U indicates an unsaturated fatty acid residue with 18 carbon atoms. The ratio of saturated fatty acid residues with 16 carbons (C16:0) to saturated fatty acid residues with 18 to 24 inclusive carbon atoms (C18:0-C24:0) comprised within the fat phase of the aerated food composition of the invention may be between 0.5 and 4.0, for example between 1 and 3.5. A higher quantity of C16:0 (palmitic) fatty acid residue in the fat phase compared to longer chain fatty acid residues provides lower viscosity at aeration temperatures between 15 and 20 °C and allows better aeration.

It is beneficial to be able to stabilize an aerated food composition without needing to use triglycerides with high chain length fatty acids. Such high chain length fatty acids, especially saturated ones, affect the organoleptic properties of the foam, giving a heavy and waxy mouthfeel. The inventors were surprised to find that aerated food compositions according to the invention could be effectively stabilized without using triglycerides with high chain length fatty acids, for example by using the method of the invention. The aerated food composition of the invention may comprise less than 2 wt.% triglycerides all of whose fatty acids have a carbon chain length less than 20, for example the aerated food composition of the invention may comprise less than 1 wt.% triglycerides all of whose fatty acids have a carbon chain length less than 20, for example the aerated food composition of the invention may be essentially free from (for example free from) triglycerides all of whose fatty acids have a carbon chain length less than 20. The aerated food composition of the invention may comprise triglycerides all of which have an average fatty acid chain length less than 20. For example, the triglyceride palmitic-oleic-stearic (POSt) has an average chain length of 17.3 as palmitic acid is C16, oleic acid is C18 and stearic acid is C18.

The aerated food composition of the invention may contain more than 95 % by weight of the total fat (for example more than 98 %, for further example more than 99 %) of triglycerides all of whose fatty acids have a carbon chain length less than 22. The aerated food composition of the invention may contain more than 95 % by weight of the total fat (for example more than 98 %, for further example more than 99 %) of triglycerides all of whose fatty acids have an average chain length less than 20.

The aerated food composition of the invention may additionally comprise inclusions, for example inclusions with an average diameter greater than 2 mm, for example inclusions which are retained by a sieve with a 2 mm opening. The inclusions may have a diameter ranging from 2 mm to 22.6 mm, for example inclusions which pass through a sieve with an opening of 22.6 mm but are retained by a sieve with a 2 mm opening. The inclusions may have a diameter ranging from 2.83 mm to 11.2 mm, for example inclusions which pass through a sieve with an opening of 11.2 mm but are retained by a sieve with a 2.83 mm opening. The inclusions may be selected from the group consisting of herbs (for example chives, dill, coriander, parsley), cereals (for example puffed rice, puffed wheat, extruded cereal pieces), fruit (for example freeze-dried fruit pieces, candied fruit or alcohol-soaked fruit), nuts, chocolate (for example chocolate vermicelli, chocolate shapes), sugar confectionery (for example cinder toffee pieces, marshmallow, sugar-panned centres such as Nestle mini SMARTIES ^® ) and combinations of these. The composition of the invention, with its two-step crystallization capability, allows inclusions to be mixed into the aerated composition after the first crystallization event without the significant loss of gas volume. The bulk fat remains fluid and so mixing in the inclusions does not cause a destructive level of shear. Once the inclusions are mixed in the second crystallization event can take place, creating the network structure in the bulk fat which provides attractive texture and long-term stability.

Conveniently the (optionally harder) inclusions are distributed substantially homogenously within the (optionally softer) aerated composition of the invention which is sufficiently structured to prevent to substantially hold the inclusions in place and prevent significant movement within the aerated composition - for example when forming part of a filled product. Thus the aerated compositions of the invention substantially hinder and/or prevent agglomeration and/or sinking of the inclusions to the bottom of the composition e.g. under gravity. Conveniently the inclusions comprise any of the following and/or mixtures thereof: fruits or fruit pieces which may be: hard fruits (e.g. hazelnuts, almonds, brazil nuts, cashew nuts, peanuts and/or similar) and/or soft fruits (e.g. raisins, cranberries, blueberries, blackcurrant, apples, pear, orange, apricot and/or similar), preferred soft fruits are dried fruits; crispy inclusions (e.g. caramel, coffee, biscuits, wafer hard candy pieces etc.); and/or any suitable mixtures thereof.

Conveniently where for example inclusions are added prior to aerating the composition they may be small having a size of no more than 0.5 mm, as the aeration process may break up larger inclusions and/or the inclusions may disrupt the aeration process (e.g. block a nozzle or conduit). The aerated food composition according to the invention may be a savoury composition such as a meat or fish flavoured filling for a pastry. The aerated food composition according to the invention may be a component of a pet food, for example a filling for an extruded dog biscuit. The aerated food composition according to the invention may be a sweet spread, such as an aerated chocolate and hazelnut spread. The aerated food composition according to the invention may be a confectionery filling; for example a sweet filling for a pastry, biscuit, extruded cereal, or moulded chocolate product.

The aerated food composition according to the invention may be a confectionery filling for a biscuit such as a wafer. Wafers are baked products which are made from wafer batter and have crisp, brittle and fragile consistency. They are thin, with an overall thickness usually between < 1 and 4 mm and typical product densities range from 0.1 to 0.3 g/cm ³ . The surfaces are precisely formed, following the surface shape of the plates between which they were baked. They often carry a pattern on one surface or on both. Wafers may also be produced by extrusion. Two basic types of wafer are described by K.F. Tiefenbacher in "Encyclopaedia of Food Science, Food Technology and Nutrition p 417-420 - Academic Press Ltd London - 1993":

1) No- or low-sugar wafers. The finished biscuits contain from zero to a low percentage of sucrose or other sugars. Typical products are flat and hollow wafer sheets, moulded cones or fancy shapes.

2) High-sugar wafers. More than 10% of sucrose or other sugars are responsible for the plasticity of the freshly baked sheets. They can be formed into different shapes before sugar recrystallization occurs. Typical products are moulded and rolled sugar cones, rolled wafer sticks and deep-formed fancy shapes.

In a still further embodiment the invention provides a filled confectionery product such as a filled chocolate tablet or bar that comprises from 50 to 70%, for example from 55 to 65%, for further example about 60% by weight of the product of an aerated food composition of the invention optionally with inclusions homogenously dispersed therein. In another embodiment of the invention provides a filled confectionery product that comprises from 20 to 70% by weight of the product of an aerated food composition of the invention (for example the aerated food composition of the invention having a porosity from 40% to 60%). Optionally the remainder of the product being a shell of chocolate-like material such as compound or chocolate that substantially encloses (for example completely encloses) the product. The aerated food composition may comprise from 1 to 70% by weight (with respect to the weight of aerated food composition) of inclusions homogenously dispersed therein with no substantial change in the porosity of the aerated food composition. Whether inclusions are substantially homogenously dispersed within the aerated food composition will be readily apparent from a visible inspection (for example of a cross- section of the product if the filling is fully enclosed). There has been a problem in the prior art that when large amounts of inclusions and/or large inclusions are added to known aerated compositions, the inclusions sink to the bottom of the filling as they are unable to be supported in place within the aerated filling which has insufficient structure to prevent or mitigate movement of inclusions within the filling which migrate under gravity due to their own weight. Therefore it is an object of one aspect of one embodiment of the present invention to provide aerated food compositions with inclusions that are dispersed evenly from top to bottom over the height of the composition and/or remain within substantially the same horizontal plane within the middle of the composition. Thus in aerated food compositions of the present invention the inclusions do not (or have reduced tendency to) to clump at the bottom of the composition.

It will also be understood that the terms top and bottom referring to a product may be interchangeable and depend for example how the product is formed and its orientation under gravity. Thus for example the top of a product in use or when packed may be the bottom of the product when formed in a mould during production. The term 'substantially horizontal' refers to a plane through an axis of the product which during storage, transport and display of the product in store is likely to be held substantially horizontal, e.g. where the product is stored flat on a largely (preferably exactly) horizontal surface. A substantially horizontal surface is typically parallel to the major plane of the product, for example the flat bottom side of large area of a filled chocolate tablet. As used herein 'substantially vertical' refers to lines or planes which are substantially perpendicular (preferably perpendicular) to a substantially horizontal (preferably exactly horizontal) line or plane as defined herein. Preferred substantially vertical orientation is vertical, especially aligned with the direction of gravity in the typical position of the product in storage, transport and/or display.

Thus the exact definition of homogeneity will depend on the product size and shape (and filling component thereof) and the amount and quantity of inclusions relative to the amount of aerated food composition, but whatever definition is used, it is strongly preferred that the aerated food compositions with inclusions avoid clumping of the inclusions at the periphery of the composition.

In one embodiment of the invention the term substantially homogeneous is used to denote that the inclusions are substantially equally and evenly dispersed within the height of an aerated food composition of the invention such height measured along a substantially vertical plane within a food product such that the inclusions are not disproportionally located at the bottom or top end of said plane, preferably are substantially evenly distributed along it.

In a yet other embodiment of the invention the term substantially homogeneous is used to denote that the inclusions are substantially equally and evenly dispersed within the aerated food composition (especially within the height thereof) when within a food product such that the inclusions have a normal distribution of linear spaces between them and one standard deviation of these spaces is no more than 10% the linear length of any dimension of the product or filling component there within, preferably such distribution being measured across a substantially vertical plane.

In another embodiment of the invention the tern substantially homogeneous may be used instead or as well as the previous definition to denotes a measure of homogeneity defined by a homogeneity index that measures how uniformly the inclusions are distributed within the composition, being especially suitable for use with large amounts of small sized inclusions.

The homogeneity index may be determined by taking an image (from X-ray tomography and/or CLSM) and measuring the number of inclusions that intersect along at least 3 parallel horizontal lines of equal length (for example at least 10 cm) located on the image to be equally spaced from each other and the image edges. The ratio of the minimum number of inclusions on one of these lines to the maximum number of inclusions on one of these lines can be defined as a number homogenous distribution index (NHDI) which for aerated fillings of the invention may be at least 0.4, for example greater than or equal to 0.5, for further example greater than or equal to 0.6, for still further example > 0.7.

In another alternative or cumulative embodiment of the invention the homogeneity index that measures how uniformly the inclusions are distributed may be determined by taking an image (from X-ray tomography and/or CLSM) and measuring along each of at least 3 parallel horizontal lines of equal length (preferably at least 1 cm) located on the image to be equally spaced from each other and the image edges, the length of each line that lies inside the inclusion. The ratio of the minimum length on one of these lines to the maximum length on one of these lines can be defined as inclusion length homogenous distribution index (ILHDI) which may be at least 0.4, for example greater than or equal to 0.5, for further example greater than or equal to 0.6, for still further example > 0.7. Homogeneity index is measured on a sufficiently large volume of sample that is appropriate for the size and concentration of inclusions that are present. Thus for example some bigger inclusions (such as blueberries) may be added to the composition at a dosing ratio of 5% in the filling by weight (corresponds to approximately 8 fruit pieces in 80g serving of filling which is approximately the amount present in one filled tablet, so a much larger quantity of filling and/or sample size of products would be needed to measure homogeneity using either measure described herein.

Homogeneity index may also be used to measure the homogeneity of the bubbles within the aerated composition and in a preferred embodiment, the bubbles may also be distributed homogenously with a NHDI and/or LHDI which may be at least 0.8, for example greater than or equal to 0.85, for further example greater than or equal to 0.9.

A second aspect of the invention provides a method of manufacturing the aerated food composition of the invention, the method comprising the steps; providing a composition comprising (for example consisting of) the non-fat solids and the non- interesterified fat, the continuous fat phase comprised within the composition being liquid; letting the composition perform a first crystallization event; aerating the composition; and controlling the temperature of the aerated composition to allow a second crystallization event in the composition. In the context of the present invention, the continuous fat phase comprised within the composition being liquid means that the solid fat content of the continuous fat phase is less than 0.1 %. Some fat in the composition may be isolated and not form part of the continuous fat phase, for example fat trapped within non-fat materials such as milk powder.

Letting the composition perform a first crystallization event may involve cooling the composition, for example cooling the composition to a temperature below the melting point of the high-melting fat but above the melting point of the medium-melting fat. The first crystallization event may be initiated by the addition of seeding crystals, for example cooling the composition to below the melting point of the high-melting fat and adding seeding crystals of high-melting fat.

The solid fat content of the composition during aeration according to the method of the invention may be between 5 and 20 % of the total fat. It has been surprisingly found that by cooling a liquid composition comprising fat to a temperature at which there is partial crystallization and a gel is formed and then whipping the composition, a stable foam is produced. The composition may form a gel before it is aerated in the method of the invention. The gel structure may continue to develop during and after aeration. Good results may be obtained by allowing the partially crystallized composition to mature before being aerated. In the method of the invention there may be a time interval of at least 2 minutes between the first crystallization event and the start of aeration.

The temperature for the first crystallization event in the method of the invention should be chosen to allow crystallization of at least part of the high-melting fat in the composition without significant crystallization of the medium-melting fat, for example without any crystallization of the medium-melting fat. The first crystallization event in the method of the invention may be performed at a composition temperature of between 16 and 24 °C. For ease of processing, the temperature may be raised before aeration, as long as some crystals remain, however, the method of the invention may be performed without any heating of the composition between the first and second crystallization events.

The temperature for the second crystallization event in the method of the invention should be chosen to allow crystallization of at least part of the medium-melting fat in the composition. The second crystallization event in the method of the invention may be performed at a composition temperature at least 5 °C lower than the composition temperature of the first crystallization event (for example between 5 °C and 20 °C lower than the composition temperature of the first crystallization event). The second crystallization event may for example be performed in a cooling tunnel, for example a cooling tunnel with a minimum temperature between 5 and 15 °C. The solid fat content of the composition may increase by at least 10 % of the total fat during the second crystallization event in the method of the invention.

The aeration step in the method of the invention may comprise mechanical agitation, for example whipping. Although foams can be obtained by non-mechanical agitation methods, such as dissolving or dispersing gas under pressure and then releasing it, to obtain the most stable foams it is preferable to apply mechanical agitation. Without wishing to be constrained by theory, it is proposed that mechanical agitation increases the wrapping of the gas bubbles with glyceride crystals. Mechanical agitation may for example be applied using rotor-stator type of equipment, such as a Haas-Mondomix aerating system. After the first crystallization event, and maturation (if any), the partial-crystallized composition may be gently sheared to allow an easy transfer to the aerating system. Mechanical agitation, for example whipping, may be applied for at least 5 s (such as the residence times in a continuous rotor-stator system), for example at least 1 minute, for example at least 5 minutes (such as in a batch whipping machine), for example at least 10 minutes, for further example at least 30 minutes. Foam stability generally increases with increasing mechanical agitation time. The aeration step in the process of the invention may comprise gas depressurization followed by mechanical whipping. Such a combination of initial bubble generation using dissolved/dispersed gas and a pressure drop followed by mechanical agitation may usefully be employed, however all process steps may be performed at or near atmospheric pressure, for example at an absolute pressure of between 800 hPa and 2100 hPa, for example between 850 hPa and 1100 hPa. The method of the invention provides a part-processed aerated composition before the second crystallization event which is both fluid and has excellent foam stability. This allows the foam to undergo processing steps which would normally be expected to damage the foam. For example, inclusions with an average diameter greater than 2 mm may be mixed into the aerated composition before the second crystallization event in the method of the invention. The inclusions may be homogeneously dispersed in the aerated composition. Inclusions with an average diameter greater than 2 mm are those which are retained by a sieve with a 2 mm opening. The inclusions may have a diameter ranging from 2 mm to 22.6 mm, for example inclusions which pass through a sieve with an opening of 22.6 mm but are retained by a sieve with a 2 mm opening. The inclusions may have a diameter ranging from 2.83 mm to 11.2 mm, for example inclusions which pass through a sieve with an opening of 11.2 mm but are retained by a sieve with a 2.83 mm opening. Small inclusions, for example those with a maximum size of 0.5 mm may be added prior to or during the aeration step. The composition after aeration may be filled into moulds before the second crystallization step, for example where the composition is a confectionery filling it may be deposited as a centre in a chocolate shell-moulding process. The composition after aeration may be combined with extruded cereal, for example co-extruded as a filling in a cereal tube which may be crimped to form cereal pillows. The composition after aeration may be laminated between wafer sheets, for example to form a wafer "book". It is advantageous that the aerated food composition of the invention may be laminated between wafer sheets, a process which applies a high degree of shear, without significant loss of aeration. It is also advantageous that the aerated food composition of the invention forms a cohesive layer between wafer sheets, allowing them to be cut into shapes without delamination.

Those skilled in the art will understand that they can freely combine all features of the present invention disclosed herein. In particular, features described for the composition of the present invention may be combined with the method of the present invention and vice versa. Further, features described for different embodiments of the present invention may be combined. Where known equivalents exist to specific features, such equivalents are incorporated as if specifically referred to in this specification. Further advantages and features of the present invention are apparent from the figures and non-limiting examples.

Examples

Example 1: Fat compositions

A series of fat compositions were prepared as shown in Table 1. Composition A is a high-melting fat (shea stearin fraction, CBI, lllexao HS 90 from AAK), composition B is a palm olein and composition C is a mixture of the shea stearin fraction with rapeseed oil. Compositions D and E comprise combinations of a high-melting fat, a medium melting fat and a low-melting fat (all non-interesterified). The components were mixed together after melting in a range of 50-70 °C and were maintained at 30 °C. Regioisomeric distribution of fatty acids: An Accela 1250 liquid chromatograph (ThermoFisher Scientific, Bremen, Germany) equipped with an Agilent Poroshell 120 EC-C18 column (2.7 μηη particle size, 2.1 x 250 mm, from BGB Analytix, Boeckten, Switzerland, cat.no. 693775-902) was used for separation of analytes. An LTQ-Orbitrap XL hybrid mass spectrometer (ThermoFisher Scientific, Bremen, Germany) was used for mass analysis, fragmentation and quantification of the triacylglycerols and fatty acids.

High resolution Orbitrap and nominal resolution linear ion trap data was integrated and extracted using the software Quanbrowser (ThermoFisher Scientific, Bremen, Germany). Chromatographic peak areas were extracted in 10 ppm m/z windows. MS Excel and its built-in Solver was used for further interpretation of the data e.g. to calculate the relative proportions of regioisomers matching the experimental data. Table 1

Example 2: Lab scale aeration

A Megatron MT-FM30 (Kinematica AG) aeration unit coupled with an IKA screw pump was used to aerate the fat mixtures outlined in Table 1. Typical settings for fat mixtures were followed but was varied from one composition to the other depending on the viscosity and kinetics of crystallization during process (Table 2.1).

Table 2.1

Foam characterization

-OR/porosity: The levels of aeration have been estimated by Over-Run (OR) or porosity ( ) measurements in standardized 3 cL plastic cups.

%OR = aerated _{χ W Q}

^-aerated

-SFC measurements: The SFC of aerated samples was determined using pulsed NMR (Nuclear Magnetic Resonance), Minispec mq20 NMR Analyzer, Bruker Biospin GMBH (Rheinstetten, Germany) using lUPAC 2.150 tempered method. Supplier standards which had solids at 0 %, 31.1 % and 72.8 % solids were used to calibrate the equipment. Approximately 2 g of aerated samples was placed in a 10 mm NMR tube for SFC measurements just after aeration and further cooling at 10 °C for 30 mins (Table 2.2). -Optical microscopy: A few drops of aerated samples were placed onto a glass slide for microscopic observation and also diluted with HOSO to be imaged using appropriate magnification and brightfield illumination using a Zeiss optical microscope. The presence or absence of gas bubbles having at least 50 % of their surface occupied by crystals was noted. The micrographs of samples C-E are shown in figure 1, where the images in the right column are diluted foam samples.

-Texture analysis: Approximately 30 grams of each aerated sample mass was poured in plastic cups and crystallized at 10°C for 30 min. Then the samples were stored for 1 day at 20°C to stabilize. The hardness of the aerated samples was measured at room temperature with a TA-HDi texture analyzer, using a conical probe of 60°, speed 1 mm/sec and 10 mm penetration with a force threshold of 5 g. 5 replicates were performed to record the maximum force of penetration. The results obtained are displayed in table 2.2.

-Oiling out measurements: Approximately 6-8 g of aerated samples were hand piped on a filter paper placed in a plastic Petri dish just after aeration and was cooled at 10°C for 30 mins before storing at 20°C for 1 day. After 1 day of storage, the stability of the aerated samples was evaluated at 28°C, 30°c and 34°C by further overnight storage. The levels of oiling out from the samples have been estimated by measuring the extent of oil released at different temperatures (Table 2.2).

„. .. . , ^released oil „

% oiling out = x 100

M sample

-Differential scanning calorimetry (DSC): The melting thermograms of aerated filling recipes were obtained with a Mettler Toledo DSC823e equipped with a TSO800GC1 gas unit (Mettler-Toledo, Ohio, United States). Nitrogen was used to purge the system. Approximately 15-20 mg of each aerated filling recipe were weighed into aluminum pans and then hermetically sealed. An empty pan was used as reference. The aerated samples were kept at 20°C for 10 min and reheated to 50°C at the rate of 10°C/min. Results were evaluated using the STARe Evaluation Software (Mettler-Toledo, Ohio, United States).

Table 2.2

From the above results it can be concluded that within the typical aeration parameters (Table 2.1) fat A and B were unable to aerate (data not shown) due to extremely fast (A) or slow (B) crystallization kinetics resulting in too high viscosity (A) or in too low crystal concentration (B) in process. Greater degrees of porosity were obtained for the blends of high-melting, medium-melting and low-melting fats (D and E) than for the simple combination of a high-melting fat with an oil (C).

Figure 1 shows the aerated foam micrographs of the fat blends (C-E), with or without diluting with liquid oil. By diluting the foams with liquid oil the bulk rheological effects normally acting on bubble shape are suppressed, but the interfacial stabilization of the crystals around the bubbles can be observed by the fact that the bubble shape do not relax. From these micrographs, around 50% of bubbles were found to have a surface coverage at least 50% of the maximal surface coverage. Maximal surface coverage corresponds to a jammed structure of crystals absorbed at a bubble ^' s interface, or at the interface between two bubbles. The dense packing of crystals at bubble interfaces gives good structural stability. Hence the non-interesterified fat blends D and E were found to retain at least 75% of the porosity after mixing with 10 wt.% fruit inclusions of 3 mm size.

It was observed that the aerated foams from compositions D and E displayed a 3-fold increase in SFC after cooling at 10°C for 30 minutes compared to the foam from composition C, despite containing similar levels of high melting fat (~20 wt.%). The foams from compositions D and E also showed higher texture and texture index. The texture index of the aerated samples is defined as texture per percent of SFA content of the fat. The presence of middle-melting fats in the fat blends allows a slow crystallization over time to provide additional texture. By tuning the proportions of high-melting, middle-melting and low-melting fats it is possible to achieve different levels of texture whilst maintaining similar levels of saturated fatty acid (SFA) content.

The aerated foams from the compositions comprising high-melting, medium-melting and low-melting fats (D and E) were equally temperature stable as the fat blend C, but advantageously displayed less oiling-out below 30°C. Figure 2 shows the structural stability of the aerated compositions C-E stored overnight at 20, 28, 30 and 34 °C. Example 3: Further fat compositions

Table 3 illustrates further composition comprising high-melting, medium-melting and low-melting fats. The components were mixed together after melting in a range of 50-70 °C and were maintained at 30 °C. Table 3

Example 4: Aerated confectionery fillings

Filling recipes 1-4 were prepared at pilot scale with compositions D, F, G, and H respectively (see Table 3 and Table 1) as elaborated in Table 4. The fillings were prepared by first blending the dry ingredients with part of the fat compositions, followed by refining with a 3 roll-refiner and treating the mixture in a Stephan mixer at 50-60 °C where the remaining fat and lecithin were added and mixed into the filling mass. Approximately 25 kg of each filling recipe was prepared with average particle size (D90) between 20-25 microns.

Table 4

Pilot scale aeration

A Haas-Mondomix aeration machine was used to aerate the fillings outlined in Table 4 at pilot scale. Typical settings for fillings were followed but was varied from one composition to the other depending on the viscosity and kinetics of crystallization during process (Table 4.1). Table 4.1

Inlet product temperature (°C) 22-24

Screw-pump speed (rpm) 100-150

Pipe jacket temperature (°C) 13-18 3C

N ₂ pressure (L/hr) 20-40

Rotor speed (rpm) 300-500

Aeration head temperature (°C) 10-15

Back pressure (bar) 0.2-5

Outlet product temperature (°C) 18-23

Filling recipes 1-4 comprising blends of high-melting, medium-melting and low-melting non-interesterified fats (D, F, G and H) were able to be successfully aerated displaying similar OR and porosity (~53%). Figure 3 shows an aerated filling micrograph of filling recipe 2, with or without diluting with liquid oil. From the micrograph, around 50% of bubbles were found to have a surface coverage at least 50% of the maximal surface coverage. Maximal surface coverage corresponds to a jammed structure of crystals absorbed at a bubble ^' s interface, or at the interface between two bubbles. The filling recipes 1-4 retained around 75% of their porosity after mixing with 10 wt. % fruit inclusions of 3 mm size.

By varying the proportions of high-melting, middle-melting and low-melting fats the filling recipes 1-4 provided different levels of texture and texture index (5.5 to 25) after 7 day storage at 20°C whilst having at similar levels of SFA (i.e. 40 %).

Figure 4 shows the structural stability and appearance of the filling recipes 1-4 after 1 week storage at around 20°C. No foam collapse or phase separation (oiling out) were observed. This demonstrates that the dense packing of crystals at bubble interfaces provides the fillings with good structural stability making them suitable for use in food products which require long shelf-lives. The creation of an extensive network during the second crystallization event helps prevent oil migration, which in the case of a filing to be used in contact with chocolate, can help prevent fat bloom. Figure 5 shows the melting thermograms of filling recipes 1-4 stored at around 20°C for 1 week, obtained using DSC. The overall melting fingerprint region for filling recipes of present invention were found to be between 24°C to 36°C. However, melting temperature of the fillings were found to be higher with higher content of high melting fat (for e.g. shea stearin).

Table 4.2

Example 5: Chocolate tablet with aerated fillings and inclusions Approximately 1 kg of aerated fillings 1, 2 and 4 containing 100 g of dried fruit inclusions of 3 mm size (see Table 4 for recipe descriptions) were shell-moulded into chocolate tablets. The aerated compositions retained most of their porosity during the depositing. The chocolate shell was a standard tempered milk-chocolate of 2-3 mm thickness. The filled moulds were cooled for 10 mins in a cooling tunnel maintained at 15 °C before being backed-off with additional tempered milk-chocolate and cooled once again for 10 min at 15 °C. Figure 6 shows the cross-section of the filled tablets with aerated fillings 1 and 3 containing fruit inclusions.