Process and apparatus for decorating a frozen confection

Abstract

A process for the manufacture of a plurality of dimensionally similar frozen confections, the process comprising the steps of: a. applying a layer of a solidifiable liquid coating material to the outer surface of a plurality of frozen confections to form a liquid coated frozen confection, b. bringing each liquid coated frozen confection into a decorating position, whereby a decorating pattern stencil is positioned between each liquid coated frozen confection and an atomising nozzle directed towards the stencil, c. generating a plurality of atomised sprays of decorating liquid, the decorating liquid having a different colour to that of the liquid coating material, by projecting the atomised sprays from each nozzle towards a respective stencil, whereby a stencilled pattern of atomised decorating liquid lands onto the surface of each liquid coated frozen confection, the timing and conditions being such that the liquid coating is in the process of solidifying, thereby producing a plurality of coated frozen confections each having a stencilled decorating pattern on a surface thereof.

Description

[0001] PROCESS AND APPARATUS FOR DECORATING A FROZEN CONFECTION

[0002] Field of the invention

[0003] The invention relates to a process for the manufacture of a plurality of dimensionally similar decorated and coated frozen confections, an apparatus for carrying out the process and the decorated and coated frozen confections made thereby.

[0004] Background of the invention

[0005] Frozen confections that have a surface decoration to enhance their visual appeal are well-known. Frozen confections that are coated with an outer coating e.g. a chocolate coating that are subsequently decorated are also well-known.

[0006] WO 2012 / 080360 A1 discloses a process for producing a frozen confection, the process comprising coating the frozen confection with a liquid coating, followed by applying a liquid patterning material (fat-based or water-based) before the liquid coating has solidified, so that the patterning material forms a pattern within the layer of the liquid coating material. The patterning material is preferably applied from a pressurised nozzle, e.g. a syringe.

[0007] Whilst such a technique is very effective at producing swirled or wavy patterns, it is not suitable for the formation of geometric patterns due to the lack of precision involved in directing a stream of liquid coating. Also, as the liquid coating forms part of the coating material, there is some inevitable mixing, which has a further negative effect on the precision of any patterning.

[0008] There therefore remains a need for a process of forming a decorated surface on a coated frozen confection that allows for precision artwork in a short period of time. Summary of the Invention

[0009] In a first aspect, the invention relates to a process for the manufacture of a plurality of dimensionally similar frozen confections, the process comprising the steps of: a. applying a layer of a liquid coating material to the outer surface of a plurality of frozen confections to form a coated frozen confection, b. bringing each coated frozen confection into a decorating position, whereby a decorating pattern stencil is positioned between each coated frozen confection and an atomising nozzle directed towards the stencil, c. generating a plurality of atomised sprays of decorating liquid, the decorating liquid having a different colour to that of the liquid coating material, by projecting the atomised sprays from each nozzle towards a respective stencil, whereby a stencilled pattern of atomised decorating liquid lands onto the surface of each coated frozen confection, the timing and conditions being such that the liquid coating has not solidified, thereby producing a plurality of coated frozen confections each having a stencilled decorating pattern on a surface thereof.

[0010] It has been found that using an atomised spray of decorating liquid in conjunction with a stencil, whilst the surface of the coating has not become solid, allows for precision artwork to be deposited in a short period of time, allowing for high quality decoration to be applied in a high throughput factory environment.

[0011] By the term “in the process of solidifying” is meant that the liquid coating is at a temperature where the coating is not yet solid and at a higher temperature than that which it will eventually reach once it has come into thermal equilibrium with the underlying frozen confection that is coated, at which point it will become solid.

[0012] 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, gelato, frozen yoghurt, sorbets, granitas, shaved ices and the like. Preferably the frozen confectionery is an ice cream.

[0013] 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 UR = - x tut) volume of premix at ambient temp

[0014] 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 0 to 150%, preferably from 60 to 150%, more preferably from 60 to 100%.

[0015] 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 confectionery 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.

[0016] Preferably the coating may completely surround or partially surround the frozen confection. Suitable fat-based confections include 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 confectionery 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 fatbased coating may consist essentially of vegetable oil and sugar, together with colours and I or flavours as required.

[0017] Coatings are typically applied to the frozen confection as liquids, but solidify over time as they cool 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. In the context of the present invention, decoration onto any chocolate coating takes pace before such a dry surface has had an opportunity to form.

[0018] 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. Preferably the coating is chocolate.

[0019] The thickness of any coating can vary according to the particular design of frozen confectionery. However coating thicknesses of from 0.5 to 3mm are preferred, more preferably from 1 mm to 2mm.

[0020] It has been found that when both the coating material and the decorating liquid are fatbased, then a superior decorating quality results.

[0021] Preferably therefore, the decorating liquid is fat-based, and is preferably chocolate or chocolate compound. The decorating liquid may have a fat content of rom 30 to 70 wt%, preferably from 40 to 60 wt%. One of the main technical benefits of the present invention is that it enables the high production rate of a plurality of dimensionally similar frozen confections to be made. Thus, preferably the time taken to carry out both steps b and c is a total of less than 5.0 seconds, preferably less than 2.0 seconds and more preferably less than 1.0 seconds.

[0022] Additionally, the present invention allows for parallel decoration of a number of coated frozen confections simultaneously. Therefore, preferably from 10 to 50, preferably 15 to 30, frozen confections are decorated simultaneously.

[0023] Typically, each frozen confection will comprise a stick, and preferably each frozen confection is held in a vertical position with the stick uppermost during steps a, b and c.

[0024] It has been found that the closer the stencil is to the surface of the coated frozen confection, the better the result of the decorated image. Therefore preferably the stencil is positioned at a distance of from 1 to 10mm from the surface of each frozen confection, more preferably 2 to 5mm.

[0025] It has been found that sufficient decorating liquid is deposited when the average thickness of the decoration image exceeds 15pm. Any more than this can increase the quality of the image but at the expense of increasing decoration times. Therefore preferably the average thickness of the deposited decoration is from 15 to 50 pm.

[0026] Preferably the atomised sprays are generated by bringing the decorating liquid into contact with a pressurised gas, although single fluid atomisation may also be used. The decorating liquid is generally brought into contact with the pressurised gas, e.g. compressed air, in an atomising apparatus, which generates small droplets of decorating liquid which exit the atomiser via a nozzle, aimed at the decorating stencil. To carry out atomisation, both the decorating liquid and the atomising gas must be pressurised. Typical levels of pressure of the decorating liquid vary from 0.5 to 3 bar gauge, preferably from 1 .0 to 3.0 bar gauge, with the atomising gas being also at a pressure of from 0.5 to 3 bar gauge, preferably from 1 .0 to 3.0 bar gauge. A wide variety of atomising nozzles may be used, and will be known to the person skilled int the art. For example, standard two-fluid atomisers with either an external or an internal mix of gas and liquid are suitable.

[0027] In a second aspect, the invention relates to an apparatus for carrying out a process as described herein, the apparatus comprising a number of operating stations, and comprising a decorating station for decorating the plurality of coated frozen confections, the decorating station comprising: a. a row of decorating pattern stencils, each positioned facing a respective atomising nozzle directed towards the stencil, b. a coated frozen confection transporter, operable to move a row of a plurality of coated frozen confections into their decorating position.

[0028] In a third aspect, the invention relates to a decorated coated frozen confection, obtainable by the process described herein.

[0029] The invention will now be illustrated by way of example, and with reference to the following figures, in which:

[0030] Figure 1 shows images of decoration produced in the examples. Spray time is shown in the graphic, with other settings being kept the same (distance = 27 cm, liquid pressure = 2 bar, air pressure = 0.7 bar, follower time = 8 ms, anticipator time = 3 ms).

[0031] Figure 2 shows images of decoration produced in the example 2. Varied settings are presented beneath the decorations; other parameters were kept the same (liquid pressure = 2 bar, air pressure = 0.7 bar, follower time = 8 ms, anticipator time = 3 ms).

[0032] Figure 3 is a side sectional view through a portion of an apparatus according to the present invention, for producing a plurality of decorated frozen confections according to the present invention. Figure 4 is a perspective view of a decorating station for use with an apparatus as shown in figure 3 as a plurality of frozen confections enter the station.

[0033] Figure 5 is another perspective view of the decorating station shown in figure 4 at a later point in time.

[0034] Turning to the figures, figure 3 shows a portion of an apparatus 10 for producing a plurality of dimensionally similar frozen confections 12 which in this case are ice creams. Each frozen confection 12 is comprised of an extruded and cut billet of ice cream into which has been inserted a stick in an earlier stage of production. In this apparatus, rows 14 of twenty such sticked ice creams 12 are produced in parallel and arrive from the left, carried by a conveyor 16. The billets of ice cream are dipped into liquid chocolate couverture at a dipping station 18, e.g. with a similar formulation as used in the examples below. The row 14 of twenty ice creams are then moved to the decoration station 20 whilst the chocolate coating has not yet solidified.

[0035] Figures 4 and 5 show detail of the decorating station 20. This comprises a stencil manifold 22 made of sheet metal which comprises a continuous stencil portion 24 that curves away from vertical and extends across the entire length of the row 14 of twenty ice creams with a decorating pattern stencil 25 aligned with each ice cream 12, and provides a cover portion 26 to contain any sprayed decoration.

[0036] Also provided is a row of twenty atomisation nozzles 30 (of which only two are shown) capable of generating a plurality of atomised sprays of decorating liquid, by bringing the decorating liquid into contact with a pressurised gas, and projecting the atomised sprays from each nozzle 30 towards a respective decorating pattern stencil 25.

[0037] In use the row 14 of twenty coated ice creams descends vertically from the position shown in figure 4 to the position shown in figure 5. Each of the sticks of each frozen confection 12 is held by a coated frozen confection transporter (not shown). As the ice creams approach the continuous stencil portion 24, the continuous stencil portion 24 also begins to move vertically downwards to match the vertical movement of the ice creams. As the continuous stencil portion 24 begins its downwards motion, spraying of the decoration liquid begins. Once the ice creams 14 meet their lowermost position, as shown in figure 5, they return to their position shown in figure 4. Throughout this movement, spraying is continued, which in this case is for a period of time of approximately 0.4 to 0.7 seconds.

[0038] During the spraying the continuous stencil portion 24 is held at a separation distance of just 5-10mm from the surface of each coated ice cream, and the distance from the nozzle to each ice cream is approximately 10cm.

[0039] Subsequently, the coating of chocolate hardens further by losing its heat to the ice cream billet, which hardens the stencilled decoration in place.

[0040] Examples

[0041] Example 1 (T30)

[0042] Examples were carried out at pilot plant scale to determine parameters for use of a Spray Systems Autojet for applying decoration to a frozen confection. In particular, the following were investigated: simulating the current line cycle time with different liquid / air pressures, and determining the amount of chocolate needed for ‘good’ coverage.

[0043] Materials

[0044] A conventional chocolate couverture with formulation and physical properties shown in table 1 was used for spraying.

[0045] Table 1 Composition

[0046] The chocolate was sprayed on a standard A4 office paper sheet to retain the highest contrast available or to better mimic the surface via a white chocolate sheet. Sample production

[0047] Samples were produced using a Spray Systems AutoJet AccuCoat Model 2250 machine with a compressed air atomiser, and two internal mixture nozzles - cone nozzle and a flat nozzle. Liquid, air pressure, and nozzles were varied in the study, as shown in Table 2.

[0048] Table 2: Spray parameters of the samples

[0049]

[0050] *29.19 was used to check flowrate and is not included in the trail list

[0051] Distance was kept the same at 27 cm and all the spraying was done using cone shaped nozzle. Other Autojet parameters - anticipation and follower times were kept to their defaults of 8 ms and 3 ms.

[0052] To produce consistent images, samples were imaged with the Karl Zeiss Smartzoom5 system (34x optical zoom). 4 images were captured for each sample, with 3 aiming for the central area of the sample where the Autojet nozzles were aimed and 1 at the edge of the page. Results and discussion

[0053] As seen in Table 1 , samples 2.1-2.18 show the atomising air pressure growing by 0.25 bar from 0.5 bar to 2.5 bar. Only the two lowest atomising air pressures (0.5, 0.75 bar) result in a measurable drop in atomisation as seen by larger droplet sizes and decreased droplet density on the paper.

[0054] This also suggests that there is little benefit in increasing the atomising air past 1 bar for this arrangement. This could help to mitigate some of the downsides associated with atomising air, such as cumulative material loss as mist and occupational exposure to fine particulate matter.

[0055] Time required for full coverage of a stencil shape

[0056] Tests conducted for how much time and chocolate are required for coverage show that the estimated thickness of decoration required to produce visually appealing samples is low i.e. 20 pm.

[0057] Table 3: Summary of chocolate coverage tests using a sun shaped stencil. Flow rate calculate from cup measurements - 1.7 g / s. Stencil area (3.742 cm2).

[0058] As can be seen in the figures, a thickness of 20pm or more provides good coverage. Example 2 (T30) n these experiments, the Spray Systems Autojet Pilot Plant was used to investigate the effects of viscosity changes on the quality of decoration and its droplet size.

[0059] Materials

[0060] The chocolate couverture of example 1 was prepared with the addition of an extra 10% w / w of pure cocoa butter that were mixed upon melting, with the physical properties and composition as shown in table 4.

[0061] Table 4

[0062] The chocolate was sprayed on a standard A4 office paper sheet to retain the highest contrast available or to better mimic the surface via a white chocolate sheet.

[0063] Sample production

[0064] Samples were produced using the Spray Systems AutoJet AccuCoat Model 2250 machine with a compressed air atomiser, and two internal mixture nozzles - cone nozzle and a flat nozzle. Liquid, air pressure, and nozzles were varied in the study, as shown in Table 5. Table 5: Spray parameters of the samples

[0065] Nozzle was maintained the same throughout the experiment (cone shaped nozzle). Other Autojet parameters - anticipation and follower times were kept to their defaults of 8 ms and 3 ms.

[0066] To produce consistent images, samples were imaged with the Karl Zeiss Smartzoom5 system (34x optical zoom). 4 images were captured for each sample, with 3 aiming for the central area of the sample where the Autojet nozzles were aimed.

[0067] Results and discussion

[0068] Upon the addition of additional fat from cocoa butter, the viscosity of chocolate quickly drops due to the effective dilution of cocoa solids and proteins present in the chocolate. This was quantified via standard ICA 46 viscosity measurement. An increase of 5% in total fat content via the addition of 10% cocoa butter in T30 results in viscosity being nearly halved; hence, significant changes in spray behaviour are to be expected. In particular, increased flow rates were found as viscosity was reduced.

[0069] In samples 30.1-30.16 (figures 1f to 1i) the effect of distance and time was investigated similarly to that in T29. In comparable measurements, we see that more chocolate is deposited.

[0070] Large distances and short spray times were still insufficient to cover the stencil with appropriate detail, while closer distances with shorter spray times gave good deposition (Figures 2a to 2c).

[0071] With reduced viscosity, the flow rate of the chocolate nearly doubles within the same pressure range; this can lead to chocolate overspray within the spray distances and time scales previously evaluated in T29. Lower viscosity also increases the mobility of the chocolate, so the large volume of chocolate starts dripping away, creating a strong gradient effect. With adjustments to accommodate an increased flow rate, reduced viscosity materials can offer certain advantages, such as reduced spraying times.

Claims

Claims1. A process for the manufacture of a plurality of dimensionally similar frozen confections, the process comprising the steps of: a. applying a layer of a solidifiable liquid coating material to the outer surface of a plurality of frozen confections to form a liquid coated frozen confection, b. bringing each liquid coated frozen confection into a decorating position, whereby a decorating pattern stencil is positioned between each liquid coated frozen confection and an atomising nozzle directed towards the stencil, c. generating a plurality of atomised sprays of decorating liquid, the decorating liquid having a different colour to that of the liquid coating material, by projecting the atomised sprays from each nozzle towards a respective stencil, whereby a stencilled pattern of atomised decorating liquid lands onto the surface of each liquid coated frozen confection, the timing and conditions being such that the liquid coating is in the process of solidifying, thereby producing a plurality of coated frozen confections each having a stencilled decorating pattern on a surface thereof.

2. A process according to claim 1 , wherein atomised sprays are generated by bringing the decorating liquid into contact with a pressurised gas.

3. A process according to claim 1 or claim 2, wherein the liquid coating material is fat-based, preferably chocolate or chocolate compound.

4. A process according to any one of the preceding claims, where the decorating liquid is fat-based, preferably chocolate or chocolate compound.

5. A process according to any one of the preceding claims, wherein the time taken to carry out steps b and c is less than 5.0 seconds.

6. A process according to any one of the preceding claims, wherein the time taken to carry out step c is less than 2.0 seconds, preferably less than 1 .0 second.

7. A process according to any one of the preceding claims, wherein from 10 to 50, preferably 15 to 30, frozen confections are decorated simultaneously.

8. A process according to any one of the preceding claims, wherein each frozen confection comprises a stick.

9. A process according to claim 8, wherein each frozen confection is held in a vertical position with the stick uppermost during steps a, b and c.

10. A process according to any one of the preceding claims, wherein the stencil is positioned at a distance of from 1 to 10mm from the surface of each frozen confection.

11. A process according to any one of the preceding claims, wherein the average thickness of the deposited decoration is from 15 to 50 pm.

12. A process according to any one of the preceding claims, wherein the pressure of the decorating liquid, when brought into contact with the pressurised gas has a pressure of from 0.5 to 3 bar gauge.

13. A process according to any one of the preceding claims, wherein the pressure of the atomising gas when brought into contact with the decorating liquid has a pressure of from 0.5 to 3 bar gauge.

14. An apparatus for carrying out a process according to any one of the preceding claims, the apparatus comprising a number of operating stations, and comprising a decorating station for decorating the plurality of coated frozen confection, the decorating station comprising: a. a row of decorating pattern stencils, each positioned facing a respective atomising nozzle directed towards the stencil,b. a coated frozen confection transporter, operable to move a row of a plurality of coated frozen confections into their decorating position.

15. A decorated coated frozen confection, obtainable by the process according to any one of claims 1 to 13.

Images