Technical Field of the Invention The present invention relates to coated frozen aerated confection products. Background to the Invention

Frozen confections which consist of ice cream, frozen yoghurt, or the like coated with chocolate, frozen fruit juice, or other coatings are popular products. These products are often supported on a stick so that they can be conveniently consumed without being held directly. Chocolate-coated stick products are one example of this type of product that have been known for many years. Frozen confection products, including those on sticks are often produced by an "extrude and cut" process. This provides an uncoated frozen confection, which may at this stage already include a stick inserted in the confection.

More recently it has been proposed to manufacture frozen aerated products with cold roller apparatus the process comprising providing two rollers with open cavities on their surfaces, filling two cavities, one on each roller, with a frozen aerated material, wherein at least one of the cavities is filled with a frozen aerated product which is then allowed to expand outside its cavity, the two cavities then being moved opposite one another and the frozen aerated product in each cavity is pressed against the frozen aerated product in the other cavity. The product is thus formed from two halves and is self-releasing from the rollers.

Once manufactured, the uncoated frozen aerated confection can then be coated by dipping into a bath of liquid coating to form the coating or may also be sprayed or enrobed with liquid coating. Once coated, the frozen products are typically blast frozen and moved from the production area to the storage areas in the factory prior to distribution. In some regions of the world such confections are manufactured at one altitude and then shipped and sold at another altitude. Such confections can also be manufactured at one altitude and experience different altitudes in the distribution chain for example when items are shipped via air freight or by road over mountain regions. Sometimes the difference in altitude can be significant. It has been observed that when such frozen aerated confections are shipped to a significantly higher altitude the coating applied can break and fall away from the surface of the frozen confection. Additionally, when such frozen confections are shipped to a significantly lower altitude, the coating applied is seemingly more easily broken by mechanical shocks.

It would therefore be desirable to prevent these altitude-related problems from arising.

Summary of the invention The present inventors have found that such altitude-related problems are caused by expansion or contraction of the frozen aerated confection. Such frozen aerated confections may comprise a significant quantity of gas bubbles entrapped within the confection. For example ice cream typically has around 30 % by volume of gas. When such gas is transported to a significantly different altitude, the entrapped gas either compresses or expands according to Boyle's Law. As the gas in entrapped within the frozen confection, such expansion or contraction will exhibit itself as an increase in the volume of the frozen confection. Thus, when the frozen aerated confection is transported to a lower altitude the external pressure increases, which causes a contraction of the entrapped gas bubbles and a commensurate contraction of the frozen aerated confection. Such contraction then causes a spacing to appear between the frozen confection and the coating applied during manufacture. Such a spacing results in the coating being less able to resist mechanical shocks, as there is no frozen confection in contact with the coating to absorb a portion of any impacting mechanical energy. Thus, the net result is that the coating is more easily broken by mechanical shocks.

When the frozen confection is transported to a higher altitude the external pressure decreases, which causes an expansion of the entrapped gas bubbles and a commensurate expansion of the frozen aerated confection. Such an expansion causes internal pressure on the coating applied during manufacture and can be sufficient to cause the coating to fail and thus crack and fall away from the surface of the frozen confection. The present inventors have surprisingly found that, although the overall volumetric expansion/contraction cannot be easily prevented, its effects can be reduced. The inventors have found that it is the linear expansion/contraction in a direction normal to the surface of the frozen confection which causes the problems described above. Therefore, the inventors have sought to reduce the linear expansion/contraction to such an extent that the mechanical problems discussed above do not arise or are greatly reduced.

Accordingly, the present invention relates to an aerated frozen confection coated in a coating, wherein the ratio of the surface area to the volume of the frozen confection before coating is greater than 0.2mm ^"1 .

Thus, the inventors have realised that the linear expansion/contraction is inversely proportional to the ratio of the surface area to the volume of the frozen confection. In other words, for a given volumetric expansion, a frozen confection will exhibit less linear expansion/contraction if it has a greater surface area to volume ratio.

The inventors have found a very clear relationship between the surface area to volume ratio and cracking upon changes in altitude. It is clear that the greater the surface area to volume ratio the less cracking occurs upon altitude change. Thus, preferably the ratio of the surface area to the volume of the frozen confection before coating is greater than 0.16mm ^"1 , more preferably greater than 0.17mm ^"1 , more preferably greater than 0.18mm ^"1 , more preferably greater than 0.19mm ^"1 , still more preferably greater than 0.20mm ^"1 . Preferably the ratio of the surface area to the volume of the frozen confection before coating is less than 0.50mm ^"1 , more preferably less than 0.45mm ^"1 . The frozen confection of the present invention is aerated. The term "aerated" means that gas has been intentionally incorporated into the product, such as by mechanical means. The gas can be any food-grade gas such as air, nitrogen or carbon dioxide. The extent of aeration is typically defined in terms of "overrun" (OR). In the context of the present invention, %overrun is defined in volume terms (measured at atmospheric pressure) as: „ volume of frozen aerated product - volume of premix at ambient temp , _{n n}

OR = x 100

volume of premix at ambient temp

The amount of overrun present in the product will vary depending on the desired product characteristics. In the context of the present invention the level of overrun is typically from 50 to 150%, preferably typically from 60 to 100%.

The inventors have also found that the resulting mechanical failures in the coating predominantly involve an edge between two relatively flat faces of a frozen confection. Upon further investigation the inventors have noted that frozen confections having edges between relatively flat faces do not have a uniform thickness of coating. In particular the coating at the edges can be noticeably thinner than the coating on the faces themselves.

This is explained because near the edges there will be proportionally more coating for a given amount of frozen confection at the immediate surface. Thus, heat will transfer from the liquid coating to the body of the frozen confection more slowly as the edges of the frozen confection become relatively warmer, thus reducing the driving force for heat transfer. The result of this is that the coating takes longer to crystallise or solidify at the edges and it therefore has an opportunity to flow away from the edges, thus making the coating thinner at the edges. This observation leads to the conclusion that such edges are sources of mechanical weakness, particularly when there is expansion/contraction of the aerated frozen confection caused by altitude changes.

The present inventors have however surprisingly found that such thinning near the edges is strongly dependent upon the radius of curvature of the frozen confection at the edge.

Accordingly, the present invention relates to an aerated frozen confection coated in a coating, the frozen confection comprising a plurality of relatively flat faces, each relatively flat face preferably having a radius of curvature substantially across the whole of the face of greater than 50mm, and wherein at least two such relatively flat faces meet to form at least one edge, wherein the edge has a radius of curvature of from 5mm to 20mm. Thus, the inventors have realised that by ensuring that the edges do not have a radius of curvature of below 5mm, the thickness of the coating at the edges surprisingly increases.

Thus, the edges no longer present such sources of mechanical failure. Although the volumetric expansion of the aerated frozen confection may remain present, its effects on the resulting mechanical damage caused is therefore reduced or eliminated.

Preferably, substantially all or all of the edges have a radius of curvature of from 5mm to 20mm.

In a preferred embodiment the at least one edge has a radius of curvature of from 6mm to 15mm, more preferably from 7mm to 13mm, or even from 8mm to 12mm.

Thus, the ratio of the thickness of the coating substantially across all of the relatively flat faces to that at the edges is preferably from 1 .5:1 to 1 : 1 .5, more preferably from 1 .3:1 to 1 :1 .3.

The relatively flat faces may be essentially flat to the eye of a consumer. Alternatively they may comprise a slight bend or undulations, provided that such curves have a radius of curvature of greater than 50mm, preferably greater than 100mm. Preferably they are essentially flat with little or no curvature.

The thickness of the coating on the relatively flat faces can vary according to the particular design of frozen confection. However coating thicknesses of from 0.5 to 3mm are preferred, more preferably from 1 mm to 2mm.

In general the aerated frozen confection is comprised of relatively flat surfaces, and as such preferably at least 70%, more preferably at least 80%, of the total surface area of the aerated frozen confection is made up of such relatively flat faces.

The aerated frozen confection is a generally rectangular cuboid with relatively flat faces at the front, back and/or sides. The relatively flat faces are preferably connected by edges having a radius of curvature of from 5 to 20mm. In one preferred embodiment the aerated frozen confection comprises two essentially parallel relatively flat side faces which are joined together by their respective perimeters by a circumferential face. The circumferential face is relatively flat in the dimension normal to the surfaces of the side faces but curves in an orthogonal dimension, in order to join together the perimeters of said side faces.

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 food manufacture). Definitions and descriptions of various terms and techniques used in frozen confection manufacture are found in "Ice Cream", 7th Edition R.T. Marshall, H.D. Goff and R.W. Hartel, Kluwer Academic / Plenum Publishers, New York 2013.

Frozen confection means a confection made by freezing a pasteurised mix of ingredients such as water, fat, sweetener, protein (normally milk proteins), and optionally other ingredients such as emulsifiers, stabilisers, colours and flavours. Frozen confections may be aerated. Frozen confections include ice cream, frozen yoghurt and the like. In a preferred embodiment the frozen confection is an ice cream.

The present invention typically utilises a frozen confection having at most 20 wt% of total sugars. 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. In preferred embodiments the frozen confection has at most 17.5 wt%, more preferably at most 15 wt%, more preferably still at most 12.5 wt%, yet more preferably at most 10 wt%, even more preferably at most 7.5 wt%, more preferably at most 6wt% total sugars. Preferably the frozen confection contains at least 1 wt%, more preferably at least 2 wt%, more preferably still at least 5 wt% total sugars.

The frozen confection further typically contains stabilisers, the primary purposes of which is to produce smoothness in body and texture, retard or reduce ice and lactose crystal growth during storage, and to provide uniformity of product and resistance to melting. Additionally, they stabilize the mix to prevent wheying off, produce a stable foam with easy cut-off in the freezer, and slow down moisture migration from the product to the package or the air. The action of stabilisers in ice cream results from their ability to form gel-like structures in water and to hold free water. Iciness can be controlled by stabilizers due to a reduction in the growth of ice crystals over time, related to a reduction in water mobility as water is entrapped by their entangled network structures in the serum phase. Suitable stabilisers include one or more of tara gum, guar gum, locust been gum, carrageenan, gelatin, alginate, carboxymethyl cellulose, xanthan and pectin. The frozen confection contains at least 0.45 wt%, preferably at least 0.5 wt%, more preferably at least 0.55 wt%, more preferably still at least 0.6 wt%, even more preferably at least 0.75 wt%, yet more preferably at least 1 .0 wt%, still more preferably at least 2.0 wt%, most preferably at least 5.0 wt% of stabilisers. Preferably the frozen confection contains at most 20 wt%, more preferably at most 15 wt%, more preferably still at most 12.5 wt%, even more preferably at most 10 wt%, most preferably at most 7.5 wt% of stabilisers.

The frozen confection may also contain non-saccharide sweetener which 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. The frozen confection contains at least 0.01 wt% of a non-saccharide sweetener, preferably at least 0.02 wt%, more preferably at least 0.03 wt%, more preferably still at least 0.04 wt%, yet more preferably at least 0.05 wt%, yet more preferably still at least 0.10 wt%, even more preferably at least 0.15 wt%, yet more preferably at least 0.20 wt%, more preferably at least 0.25 wt%, most preferably at least 0.50 wt% of a non- saccharide sweetener. Preferably the frozen confection contains at most 2.5 wt%, more preferably at most 2 wt%, more preferably still at most 1 wt% of a non-saccharide sweetener.

Preferably the product comprises at least 30g, more preferably at least 40g, more preferably still at least 50g, yet more preferably at least 60g, yet more preferably still at least 70g, even more preferably at least 80g, more preferably at least 100g, yet more preferably at least 125g, still more preferably at least 150g, even more preferably at least 200g frozen confection. Preferably the product comprises at most 500g, more preferably at most 350g, more preferably still at most 300g, still more preferably at most 250g, most preferably at most 225g frozen confection.

As discussed, the present invention provides coated frozen confections. Coating means any edible material which can be used to form a coating layer on a frozen confection. Coatings may be fat-based, such as chocolate (dark chocolate, white chocolate, milk chocolate), or a chocolate analogue or couverture. The term "chocolate" is not intended to be limited to compositions that can legally be described as chocolate in any particular country but includes any products having the general character of chocolate. It therefore includes chocolate-like materials which are made using fats other than cocoa butter (for example coconut oil). Chocolate usually contains non-fat cocoa solids, but it is not essential that it does so (e.g. white chocolate). The term chocolate analogue means chocolate-like fat-based confection compositions made with fats other than cocoa butter (for example cocoa butter equivalents, coconut oil or other vegetable oils). Such chocolate analogues are sometimes known as couvertures. Chocolate analogues need not conform to standardized definitions of chocolate which are used in many countries. In addition to fat and cocoa solids, chocolate and chocolate analogues may contain milk solids, sugar or other sweeteners and flavourings. A fat-based coating may consist essentially of vegetable oil and sugar, together with colours and / or flavours as required.

Frozen confection products, including stick based frozen confections, can be coated using various different techniques. The frozen confection can be dipped into liquid coatings for a certain time to form the coating. The most commonly used method of dipping, on an industrial scale, is to hold products upside down by their sticks on an indexing conveyor. The conveyor moves the products, stepwise, toward a dipping bath. When over the bath, the products are pushed down in to the coating, pulled back up and then indexed away by the conveyor. In a simpler and cheaper dipping method, the ice cream products are continuously moved though the bath. The products are initially held upside down by their sticks. They are then rotated into a horizontal position in order to clear the side of the bath. They are then rotated back to the upside down (vertical) position, thereby dipping the ice cream into the coating while the products are moved along the length of the bath. At the end of the bath they are rotated back to the horizontal position to clear the edge of the tank. Finally they are rotated back to the upside down position to allow the coating to set and the excess coating to run-off. As an alternative to dipping, spraying can be used to coat products, in particular stick based products. Enrobing can be used to coat products without sticks. The product is placed on a mesh conveyor belt and passed through a waterfall of coating (known as a curtain) typically formed by pumping liquid coating through an aperture in the form of a horizontal slot. This operation coats the top, front, back and sides of the bar. An air knife may be used to blow off the excess coating, which drains through the mesh conveyor. Finally, the mesh conveyor carries the product into a shallow bath of coating thereby immersing the bottom of the product and coating it.

Coatings are applied to the frozen confection as liquids, but solidify when they are cooled down, for example as a result of contact with the frozen confection. Chocolates have complex solidification behaviour because they contain mixtures of different triglycerides which can crystallize in different forms. For example, cocoa butter can exist in six different crystalline forms (polymorphs). As chocolate solidifies, triglycerides begin to crystallize. Within a few seconds the chocolate becomes dry to the touch and has plastic or leathery texture. Crystallization continues slowly, so that it typically takes several hours or days for the triglycerides to fully crystallize and so that the chocolate reaches its maximum brittleness. Chocolate made from fats other than cocoa butter displays similar behaviour, but typically crystallizes over a narrower temperature range and reaches maximum brittleness more quickly. Similarly, water based coatings freeze to create a lattice work of ice crystals around the frozen confection core. Preferably the coating is chocolate.

The product can be partially coated but in a preferred embodiment it is fully coated. Preferably the product comprises at least 5g, more preferably at least 10g, more preferably still at least 15g, yet more preferably at least 20g, still more preferably at least 25g, even more preferably at least 30g, yet more preferably at least 40g, most preferably at least 50g of coating. Preferably the product comprises at most 100g, more preferably at most 80g, more preferably still at most 70g, most preferably at most 60g of coating.

Preferably the ice content of the aerated frozen confection at -12°C is at least 40 wt%, more preferably at least 45 wt%, more preferably still at least 50%, yet more preferably at least 55 wt%, most preferably at least 60 wt%. Preferably the ice content of the frozen confection at -12°C is at most 70 wt%, more preferably at most 65 wt%, most preferably at most 60 wt%. Preferably the ice content of the aerated frozen confection at -8°C is at least 40 wt%, more preferably at least 45 wt%, more preferably still at least 50%, yet more preferably at least 55 wt%, most preferably at least 60 wt%. Preferably the ice content of the frozen confection at -8°C is at most 70 wt%, more preferably at most 65 wt%, most preferably at most 60 wt%. Brief Description of the figures

Figure 1 is a chart showing the barometric pressure needed to cause 70% of the samples to show cracking in the coating as a function of the ratio of the surface area to volume of the frozen confections.

Figure 2 is a chart showing the ratio of the thickness of the coating at the face to that at the corners as a function of the radius of curvature of the corners. Figure 3 is a chart showing the percentage of samples that showed cracking as a function of the pressure the samples were taken to.

Examples Example 1 - Effect of Surface area-to-volume ratio

Sample Preparation

Ice creams of different surface area to volume ratio were produced by extruding through a first nozzle. The nozzle cross section was approximately rectangular at 40mm by 97 mm with rounded corners of radius of 19mm. Ice creams of different sizes were produced by slicing through the extruded ice cream after lengths varying from 15 to 30mm were extruded

Details are given below in Table 1 :

Table 1

Ice

Chocolate Chocolate Ice Cream Cream

Height Area Volume Volume Mass Volume Volume SA/V

(mm) (mm ² ) (mm ³ ) (ml) Chocolate (g) (mm ³ ) (ml) (mm ^-1 )

15 1 1518.22 17134.18 17.13 21.42 58663.35 58.7 0.196

18 12257.51 18233.92 18.23 22.79 70396.02 70.4 0.174

21 12996.80 19333.67 19.33 24.17 82128.69 82.1 0.158

24 13736.09 20433.42 20.43 25.54 93861 .36 93.9 0.146

25 13982.52 20800.00 20.80 26.00 97772.25 97.8 0.143 27 14475.38 21533.16 21.53 26.92 105594.03 105.6 0.137

30 15214.67 22632.91 22.63 28.29 1 17326.70 1 17.3 0.130

Ice creams of different surface area to volume ratio were produced by extruding through a second nozzle. The nozzle was approximately rectangular at 34mm by 75 mm with rounded corners of radius of 17mm. Ice creams of different sizes were produced by slicing through the extruded ice cream after lengths varying from 15 to 30mm were extruded

Details are given below in Table 2:

Table 2

In all cases, the average chocolate coating thickness was kept constant at 1 .49mm. This was achieved by:

a. using a CAD package to determine the surface area of each ice cream slice b. the surface area allows calculation of the volume of chocolate required to achieve a 1 .49mm thick coating

c. the chocolate density of 1.25g/ml was used to convert chocolate volume to a mass of chocolate

d. When dipping the ice cream slices, the temperature of the chocolate was varied to achieve the calculated level of chocolate coverage on the ice cream slice. Once chocolate coated, the products were stored for 2 weeks at -25°C prior to altitude testing. Altitude Testing

All samples were equilibrated to -18°C for 8-12 hours prior to altitude testing. 15 of each sample type were loaded in to an Angelantoni TD 150 C thermostatic altitude chamber at -18°C and ambient pressure (approx. l OOOmbar). The pressure inside the chamber was then reduced by 25mbar at a rate of 470mbar/min and held at this pressure for

2.5hours. Following this, the chamber was returned to ambient pressure, opened and the number of samples with cracked chocolate coating was measured. Following sample inspection, the chamber was re-sealed and pressure reduced by a further 25mbar (at a rate of 470mbar/min) and holding this pressure for 2.5hours. This process of reducing the pressure in 25mbar increments, waiting 2.5hours and then inspecting the products was repeated until 70% of the samples in each set had cracked. The surface area :

volume ratio of each sample was plotted against the pressure drop required to crack 70% of the samples and this can be seen in Figure 1.

Example 2 - Effect of rounded edges

Coating thickness

Ice cream confectionery compositions were produced by extruding the ice cream and cutting the extruded ice cream into pieces with a wire. It was found that such ice cream confectioneries were naturally produced with edges and corners having a radius of curvature of approximately 3mm.

Each ice cream composition comprised two essentially parallel relatively flat side faces which are joined together by their respective perimeters by a circumferential face. The circumferential face is relatively flat in the dimension normal to the surfaces of the side faces but curves in an orthogonal dimension, in order to join together the perimeters of said side faces.

The radius of curvature of the edges where the faces join each other was varied by removing a small amount of ice cream from the edges with a heated knife and measuring with radius gauges. The ice cream confectioneries were coated in a chocolate composition by dipping the ice cream into a liquid bath of molten chocolate. The coating was formed by removing the ice cream confection from the bath and allowing the chocolate coating to crystallise. The thickness of the chocolate coating on the flat faces was measured to be approximately 1.4mm ± 0.1 mm. This was measured by cutting cross sections of the product, taking pictures of the coating using a microscope and then analysing these pictures (determining magnification factor by taking an image of a graticule and then counting number of pixels over the depth of chocolate) to derive a chocolate thickness. In total, 26 measurements of chocolate thickness were made (13 evenly spaced measurements over the entire face x 2 flat faces).

The thickness of the chocolate coating at the edges was also measured (same method as above), taking 26 (13 evenly spaced measurements over the edges circumference x 2 edges) measurements per ice cream confection. The results were plotted as a ratio of the thickness at the face to the thickness at the edge as a function of radius of curvature of the edge or corner. The results are shown in Figure 2.

Although there is some scatter in the figure, it can be clearly seen that there is a trend towards having more consistent thickness of chocolate coating with increasing radius of curvature at the edges and corners.

Altitude cracking In order to simulate potential problems arising when moving to a different altitude, tests were carried out on the produced coated ice cream confectioneries.

A batch of 20 ice cream confectioneries which all had edges and corners with a radius of curvature of approximately 3mm were placed in a pressure chamber. All samples were equilibrated to -18°C for 8-12 hours prior to altitude testing. 20 of each sample type were loaded in to an Angelantoni TD 150 C thermostatic altitude chamber at -18°C and ambient pressure (approx. l OOOmbar). The pressure inside the chamber was then reduced by 25mbar at a rate of 470mbar rnin ^"1 and held at this pressure for

2.5hours. Following this, the chamber was returned to ambient pressure, opened and the number of samples with cracked chocolate coating was noted. Following sample inspection, the chamber was re-sealed and pressure reduced by a further 25mbar (at a rate of 470mbar min ^"1 ) and holding this pressure for 2.5hours. This process of reducing the pressure in 25mbar increments, waiting 2.5hours and then inspecting the products was repeated until the pressure had been reduced to 775mbar.

The percentage of coated ice creams that had a crack in the coating were noted and the results plotted in Figure 3.

As can be seen, when the target pressure is 875 mbar, 100% of the coated ice creams had cracked coatings.

The experiment was repeated with ice cream confectioneries with edges and corners having a radius of curvature of 10mm. The results are also shown in Figure 3. As can be seen, when the target pressure is 875 mbar, only 5% of the coated ice creams had cracked coatings.