Methods of forming images onto chocolate surfaces of foods items

Abstract

The invention provides a method of forming an image on a surface of a food item having an outer packaging, wherein the food item comprises a chocolate surface, the method comprising the step of irradiating the chocolate surface of the food item at one or more locations using a laser to form an image thereon; wherein the step of irradiating the chocolate surface comprises passing laser energy through the outer packaging and onto the chocolate surface of the food item at the one or more locations, and wherein the laser has a wavelength of around 7000 nm to 22000 nm.

Description

[0001] Methods of Forming Images onto Chocolate Surfaces of Food Items

[0002] Technical Field of the Invention

[0003] The present invention relates to methods of forming an image onto the surface of a food item. The invention further relates to methods of forming an image on a surface of a food item comprising a chocolate surface through outer packaging material in which the item is located.

[0004] Background to the Invention

[0005] Methods of producing images, text, and / or designs on food items are well known. For food items comprising a chocolate surface in particular, methods involving moulds or handpainting have been widely used for forming images, text, and / or designs on the surface of chocolate products for many years.

[0006] With the aim of increasing the range of customer experience, there is a growing interest in the production of personalised or customised designs on the surface of food items. Conventional methods of forming images, text, and / or designs on the food items are generally not cost- or time-effective for this purpose. Conventional methods can also lack the detail, accuracy and resolution expected by consumers.

[0007] Moreover, customising products at the point of sale would further enhance the customer experience. Such methods require high accuracy, high resolution and a quick turnaround time. Customisations at the point of sale may include, for example, adding a name or image to a food item from a database or via user input (such as a drawing or from a camera).

[0008] Thus, in more recent years, methods involving the use of lasers to etch images, text, and / or designs onto the surface of food items have been developed to address the above problems. Laser etching allows for the low-cost and time-effective production of seasonal or single-run designs onto the surfaces of food items, as well as images with a higher degree of accuracy and intricacy.

[0009] For food items comprising chocolate surfaces in particular, known methods for laser etching require controlled and specific laser parameters (for example, laser power, laser etching speed and laser wavelength) and environmental conditions. Due to its relatively low melting temperature, chocolate can become easily scorched during laser etching and its taste compromised.

[0010] Additionally, known laser etching methods are generally achieved without the presence of any outer packaging to avoid damage to the pack material and to ensure that a clear mark is formed on the chocolate surface. The use of unwrapped food items prior to laser etching may increase the risk of food safety issues and Good Manufacturing Practices (GMP) concerns as the naked food item may contact the laser etching equipment or be unnecessarily exposed to the environment for longer periods of time.

[0011] Thus, current laser etching methods cannot simply be incorporated into existing product lines as the food item cannot be manufactured and packaged in accordance with existing processes, and then transported elsewhere for laser etching, without the need for additional steps of unwrapping and re-wrapping the food item, or without the need to expose the food item to the environment for unacceptable lengths of time before packaging them.

[0012] EP2008527B1 and US2017 / 354164A1 both disclose methods of laser etching chocolate confectionery items directly, without the presence of an outer packaging at a location above the area of the chocolate confectionery item which is irradiated. Thus, the laser etching methods of the prior art do not solve the above problems and are likely to cause disruption to existing product lines. In addition, the resolution of the images etched onto the surface of the chocolate is not optimal, using the laser methods described due to the confectionary items’ direct exposure to environmental conditions.

[0013] It would therefore be advantageous to be able to etch high resolution images onto chocolate surfaces of food items that have been wrapped, whilst mitigating or avoiding damage to the wrappers and chocolate. This will also provide the added benefits of reducing process complexity (e.g. reducing process steps and need for environmental control), improving reliability, stability and longevity of the markings and enabling flexibility in supply chain of laser irradiated products e.g. in non-GMP areas. Additionally, varying the laser resolution may also improve the resolution and quality of the resulting image. It would also be advantageous to be able to etch higher resolution images onto chocolate surfaces through wrappers.

[0014] It is therefore an aim of embodiments of the invention to provide an improved method of forming images onto chocolate surfaces of food items through the outer packaging which overcomes the problems of the prior art mentioned above.

[0015] It is also an aim of embodiments to the invention to overcome or mitigate at least one problem of the prior art, whether disclosed herein or not.

[0016] Summary of the Invention

[0017] In accordance with the first aspect of the invention, there is provided a method of forming an image on a surface of a food item having an outer packaging, wherein the food item comprises a chocolate surface, the method comprising the step of irradiating the chocolate surface of the food item at one or more locations using a laser to form an image thereon; wherein the step of irradiating the chocolate surface comprises laser energy passing through the outer packaging and onto the chocolate surface of the food item at the one or more locations, and wherein the laser is a CO2 laser.

[0018] The laser energy may pass through the outer packaging above only the location or locations where a mark is desired on the chocolate surface.

[0019] In some embodiments, the laser energy may pass through the outer packaging directly above, or perpendicular to, the location on the chocolate surface that is irradiated. In some embodiments, the laser energy may pass through the outer packaging above and at an angle to the location on the chocolate surface that is irradiated. The term “above” when used in relation to the chocolate surface describes both “directly above” and “above and at an angle”.

[0020] In some embodiments the laser power is at least 1 W, 2W, 3W, 4W, 5W, 6W, 7W, or 8W. The laser power may be no more than 9W, 8W, 7W, 6W, 5W or 4W.

[0021] In some embodiments the laser power is between 1 -9W, 1 -8W, 1 -7W, 1 -6W, 1 -5W, or 1 - 4W. Alternatively, the laser power may be between 8-9W, 7-9W, 6-9W, 5-9W, 4-9W, 3-9W or 2- 9W. In some embodiments, the laser wavelength may be between around 7000 nm to

[0022] 15000nm or between around 9000 nm to 11000 nm. Optionally, the laser wavelength may be around 10600 nm.

[0023] The laser etching speed may be at least 800 mm s1, 1200 mm s1, 1600 mm s1, 2000 mm s'1, 2400 mm s1, 2800 mm s1, 3200 mm s1, 3600 mm s1, 4000 mm s1, 6000 mm s1, 8000 mm s'1, 10000 mm s1, 20000 mm s1, 30000 mm s1, 40000 mm s1, 50000 mm s1, 60000 mm s1, or at least 70000 mm s1,. The laser etching speed may be no more than 75000 mm s1, 70000 mm s'1, 60000 mm s1, 50000 mm s1, 40000 mm s1, 30000 mm s1, 20000 mm s1, 10000 mm s1, 8000 mm s1, 6000 mm s1, 4000 mm s1, or no more than 2000 mm s1.

[0024] The laser etching process may take less than 2 hours, less than 1.5 hours, less than 1 hour, less than 30 minutes, less than 20 minutes, less than 10 minutes, less than 8 minutes, less than 6 minutes, less than 4 minutes, less than 2 minutes, or less than 1 minute to form the etched image on the chocolate surface of the food item.

[0025] The laser etched image may have a resolution of at least 20 Dots Per Inch (DPI), at least 30 DPI, at least 40 DPI, or at least 50 DPI. The laser etched image may have a resolution of no more than 5000 DPI, no more than 4500 DPI, or no more than 4000 DPI.

[0026] In some embodiments, the laser etched image has a resolution of around 20-3000 DPI. Preferably, the laser etched image has a resolution of around 50-2400 DPI.

[0027] It is believed that the laser energy passes through the outer packaging and marks the chocolate surface of the food item at the location irradiated without changing the structural integrity and / or functional integrity of the outer packaging. As such, it is believed that the outer packaging may not be marked or damaged by the inventive laser irradiation process.

[0028] The laser irradiation of the chocolate surface of the food item may etch the image on the chocolate surface as a result of the change to the chocolate microstructure at the location where the laser irradiates the surface. At the location irradiated, it is believed that there is a change in the fat structure of the chocolate at the location irradiated. It is believed that this change in the microstructure changes the way that the light is scattered and thus the image is visualised. The outer packaging may comprise one or more layers. The outer packaging may comprise a flexible film, which may comprise one or more layers. In embodiments with multiple layers, each layer may be laminated or connected to its adjacent layer or layers.

[0029] The outer packaging may comprise one or more materials selected from the group consisting of: polymeric material, paper, paperboard, cardboard, cork, ceramic, food, leather, rubber, silicon, stone, granite, marble, textiles, wood, metal, glass and any combination thereof. For example, the outer packaging may comprise a combination of a polymeric material and paper. In some embodiments, the outer packaging comprises a laminated structure wherein each layer may comprise one or more of the aforementioned materials.

[0030] In embodiments in which the outer packaging comprises multiple layers, each layer may be independently selected from at least one of the aforesaid materials, or any combination thereof.

[0031] Preferably, the outer packaging comprises at least one polymeric material.

[0032] In some embodiments, the outer packaging may be selected from at least one polymeric material selected from the group consisting of: polyethylene terephthalate (PET), polyethylene, polyvinyl chloride (PVC), polyethylene terephthalate glycol (PETG), polypropylene (PP), polyester (PE), biaxially orientated polypropylene (BOPP), linear low-density polyethylene (LLDPE), acrylonitrile butadiene styrene (ABS), polyamide (PA), polycarbonate (PC), poly(methyl methacrylate) (PMMA), polyoxymethylene (POM), polybutylene terephthalate (PBT), (BET) and any combination thereof. The at least one polymeric material may be a foam or a laminate. In embodiments in which the outer packaging comprises multiple layers, each layer may be independently selected from at least one of the aforesaid polymeric materials, or any combination thereof.

[0033] In some embodiments, the outer packaging covers the entirety of the food item so as to protect the food item from the external environment. In some embodiments, the outer packaging may be sealed around the food item, or alternatively, the outer packaging may be sealed only partly around the food item. Preferably, the food item remains entirely covered and sealed by the outer packaging during the laser etching process. In such embodiments, the packaging may provide food safety and GMP regulations.

[0034] The outer packaging may comprise a transparent, translucent, or opaque material above the chocolate surface of the food item which is irradiated. The outer packaging may comprise a mixture of transparent, and / or translucent, and / or opaque materials at different locations across the outer packaging.

[0035] The outer packaging may comprise a coloured material above the chocolate surface of the food item which is irradiated. The outer packaging may be opaque and coloured above the chocolate surface of the food item which is irradiated. The outer packaging may be transparent or translucent and coloured above the chocolate surface of the food item which is irradiated. The outer packaging may comprise more than one colour across the outer packaging at different locations.

[0036] The outer packaging may comprise a thickness less than 10 mm, 8 mm, 6 mm, 4 mm, 2 mm, 1 mm, 0.95 mm, 0.90 mm, 0.85 mm, 0.80 mm, 0.75 mm, 0.70 mm, 0.65 mm, 0.60 mm, 0.55 mm, 0.50 mm, 0.45 mm, 0.40 mm, 0.35 mm, 0.30 mm, 0.25 mm, 0.20 mm, 0.15mm, or less than 0.10 mm, above chocolate surface of the food item which is irradiated. The outer packaging preferably has a thickness below 0.55 mm above the chocolate surface of the food item which is irradiated. At this thickness, there is minimal or no damage to the outer packaging.

[0037] According to a method of this invention, the food item may be subjected to a preconditioning step prior to laser irradiation. The pre-conditioning step may comprise a step selected from the group consisting of: a heat conditioning step where the food item is heated directly, a hot air conditioning step where the food item is placed in a temperature controlled environment, a microwave conditioning step, and an infrared conditioning step. The preconditioning step may comprise one, or more than one steps. Typically, the pre-conditioning step comprises one step.

[0038] The pre-conditioning step may comprise placing the wrapped food item in a temperature- controlled environment at a temperature of between 18-35 °C; preferably between 24-30 °C. The pre-conditioning step may comprise a pre-conditioning time of less than 30 hours. For example, the pre-conditioning time may be around 24 hours for a hot air conditioning step, 3 minutes for a microwave conditioning step and 20 seconds for an infrared conditioning step.

[0039] Additionally, or alternatively, the food item may be subjected to a post-conditioning step following laser irradiation. The post-conditioning step may be selected from the group consisting of; a heat conditioning step where the food item is heated directly, a hot air conditioning step where the food item is placed in a temperature controlled environment, a microwave conditioning step, or an infrared conditioning step. The post-conditioning step may comprise one, or more than one step.

[0040] In some embodiments, the post-conditioning step may comprise placing the wrapped food item in a temperature-controlled environment at a temperature of between 20-30 °C, 10-20 °C, 0-10 °C, -10-0 °C, or -20 - -10 °C. For example, a first post-conditioning step may comprise placing the wrapped food item in a temperature-controlled environment of between 20-30 °C, and a second post-conditioning step may comprise placing the wrapped food item in a temperature- controlled environment of 10-20 °C.

[0041] In another embodiment, a post-conditioning step may comprise an infrared conditioning step that achieves a chocolate surface temperature of around 20-30 °C.

[0042] A single post-conditioning step may comprise a post-conditioning time of less than 30 hours, less than 20 hours, less than 10 hours, less than 5 hours, less than 1 hour, less than 30 minutes, or less than 1 minute.

[0043] The pre-conditioning step and / or post-conditioning step described herein improve the quality and resolution of the image formed on the chocolate surface.

[0044] The laser etching methods according to this invention may be applied to the etching of flat, angular, or curved chocolate surfaces.

[0045] The chocolate surface of the food item may be selected from the group consisting of: white chocolate, milk chocolate, plain chocolate, compound chocolate, dark chocolate, ruby chocolate, caramelised chocolate and any combination thereof. The chocolate surface may comprise a fat-based compound chocolate which may fall within regulatory-approved chocolate definitions in one or more countries.

[0046] In some embodiments, the food item may be selected from a group consisting of; a chocolate confectionery item, a centre-filled chocolate product, a layered food item comprising at least one chocolate layer, a chocolate coated bakery item, a composite food item comprising a chocolate portion or layer, solid chocolate perse, or any combination thereof.

[0047] The food item may comprise further added ingredients, flavourings, and / or colourings. The food item may comprise a chocolate confectionery item, such as solid chocolate for example, and may further comprise at least one ingredient selected from, but not limited to, the group consisting of: fat-based fillings, water-based fillings, nuts, fruit, biscuit pieces, rice, nougat, marshmallow, candy, jelly candies, caramel, or other confectionery pieces, flavourings, or a combination thereof.

[0048] The chocolate surface of the food item may additionally comprise inclusions. The inclusions at the chocolate surface may comprise any of the additional ingredients described above, or any combination thereof.

[0049] The chocolate surface of the food item may have a fat content of at least 5%, at least 10%, at least 15%, at least 20%, at least 25%, or at least 30%. The chocolate surface may have a fat content of no more than 60%, no more than 55%, no more than 50%, no more than 45%, or no more than 35%.

[0050] In some embodiments, the image formed on the chocolate surface of the food item may be selected from the group consisting of; text, photographs, personalised designs, customised designs, personalised messages, seasonal messages, seasonal designs, labels, logos, barcodes, quick response (QR) codes, or combinations thereof.

[0051] In accordance with a second aspect of the invention, there is provided a method of forming an image on a surface of a food item having an outer packaging , wherein the food item comprises a chocolate surface, the method comprising the step of irradiating the chocolate surface of the food item at one or more locations using a laser to form an image thereon; wherein the step of irradiating the chocolate surface comprises laser energy passing through the outer packaging and onto the chocolate surface of the food item at the one or more locations, and wherein the laser has a wavelength in the region of 7000 nm to 22000 nm.

[0052] The laser energy may pass through the outer packaging above only the location or locations where a mark is desired on the chocolate surface.

[0053] The laser wavelength may be in the mid-wave infrared (MWIR) region, or the long- wavelength infrared (LWIR) region.

[0054] In one embodiment, the laser wavelength may be at least 7000 nm, 7500 nm, 8000 nm, 8500 nm 9000 nm, 9500 nm or at least 10000 nm. The laser wavelength may be no more than 22000 nm, 21000 nm, 20000 nm, 19000 nm, 18000 nm, 17000nm, 16000 nm, 15000 nm, 14500 nm, 14000 nm, 13500 nm, 13000 nm, 12500 nm, 12000 nm, 11500 nm, or no more than 11000 nm.

[0055] The laser wavelength may be between 7000-21000 nm, 7000-20000nm, 7000-19000 nm, 7000-18000nm, 7000-17000 nm, 7000-16000 nm, 7000-15000 nm, 7000-14500 nm, 7000-14000 nm, 7000-13500 nm, 7000-13000 nm, 7000-12500 nm, 7000-12000 nm, 7000-11500 nm, 7000- 11000 nm. Alternatively, the laser wavelength may be between 7500-22000 nm, 8000-22000 nm, 8500-22000 nm, 9000-22000 nm, 9500-22000 nm, 10000-22000 nm. Preferably, the laser wavelength may be between 9000-11000 nm.

[0056] The laser power, laser etching speed, resolution and the laser etching process may be as described for the first aspect of the invention.

[0057] The food item and outer packaging may be as described for the first aspect of the invention.

[0058] The method may further comprise one or both steps of pre-conditioning the food item and post-conditioning the food item, which may be as described in relation to the first aspect of the invention hereinabove.

[0059] In accordance with a third aspect of the invention, there is provided a method of forming an image on a surface of a food item having an outer packaging, wherein the food item comprises a chocolate surface, the method comprising the step of irradiating the chocolate surface of the food item at one or more locations using a laser to form an image thereon; wherein the step of irradiating the chocolate surface comprises laser energy passing through the outer packaging and onto the chocolate surface of the food item at the one or more locations, and wherein the method further comprise one or both steps of pre-conditioning the food item and post-conditioning the food item.

[0060] The food item and outer packaging may be as described for the first aspect of the invention.

[0061] The pre-conditioning step may be performed before inserting the food item into the packaging or when the food item is wrapped before irradiating the chocolate surface or a combination thereof.

[0062] The post-conditioning step may be performed after irradiating the chocolate surface.

[0063] The pre-conditioning step and / or post-conditioning step may comprise a heat conditioning step where the food item is heated directly, a hot air conditioning step where the food item is placed in a temperature controlled environment, a microwave conditioning step, or an infrared conditioning step.

[0064] The pre-conditioning step and / or post-conditioning step may comprise one or more than one step, wherein each step may comprise placing the wrapped food item in a temperature- controlled environment at a set temperature for a specified length of time.

[0065] The pre-conditioning step and / or post-conditioning step may be as described in relation to the first aspect of the invention hereinabove.

[0066] In accordance with a fourth aspect of the invention there is provided a method of forming an image on a surface of a food item having an outer packaging, wherein the food item comprises a chocolate surface, the method comprising the step of forming the image by using a laser to change the fat microstructure and / or content at one or more locations on the chocolate surface through irradiating the chocolate surface of the food item at the one or more locations to form the image thereon; wherein the step of irradiating the chocolate surface comprises laser energy passing through the outer packaging and onto the chocolate surface of the food item at the one or more locations.

[0067] The food item and outer packaging may be as described for the first aspect of the invention.

[0068] In some embodiments, it is believed that the chocolate surface of the food item which has been irradiated comprises a lower total fat content compared to surrounding areas that have not been subject to laser irradiation; this consequently reveals non-fat solid particles that scatter the light due to increased roughness and enable the image to be visible on the chocolate surface.

[0069] In some embodiments, the laser source used to irradiate the chocolate surface of the food item resulting in a change to the chocolate microstructure and fat content may comprise a fibre laser, a solid-state laser, a gas laser, or a semiconductor laser. The laser may be as described hereinabove for the other aspects of the invention.

[0070] According to a fifth aspect of the invention there is provided a packaged food item produced by the method of any one of the first to fourth aspects of the invention.

[0071] According to a sixth aspect of the invention, there is provided a method of forming an image on a surface of a food item having multiple layers of outer packaging, wherein the food item comprises a chocolate surface, the method comprising the step of irradiating the chocolate surface of the food item at one or more locations using a laser to form an image thereon; wherein the step of irradiating the chocolate surface comprises laser energy passing through the multiple layers of outer packaging and onto the chocolate surface of the food item at the one or more locations.

[0072] In some embodiments at least one layer of outer packaging is not substantially marked or substantially damaged by the laser irradiation.

[0073] The food item and outer packaging may be as described for the other aspects of the invention. The laser may be as described for the other aspects of the invention. In some embodiments the laser is a CO2 or fibre laser. In some embodiments the irradiation step may be as described for the other aspects of the invention. The outer packaging may comprise at least 1 , at least 2, at least 3, at least 4, at least 5, at least 6, at least 7 , or at least 8 layers. Each layer may comprise the same or different material or materials. Each layer may comprise at least one material independently selected from the group consisting of: polymeric material, paper, paperboard, cardboard, glass and any combination thereof. In some embodiments each layer may comprise at least one polymeric material selected from the group consisting of: polyethylene terephthalate (PET), polyethylene, polyvinyl chloride (PVC), polyethylene terephthalate glycol (PETG), polypropylene (PP), polyester (PE), biaxially orientated polypropylene (BOPP), linear low-density polyethylene (LLDPE), acrylonitrile butadiene styrene (ABS), polyamide (PA), polycarbonate (PC), poly(methyl methacrylate) (PMMA), polyoxymethylene (POM), polybutylene terephthalate (PBT), (BET) and any combination thereof. The at least one polymeric material may be a foam or a laminate.

[0074] In some embodiments, at least two layers may be laminated or connected to each other. In embodiments with three or more layers, each layer may be laminated or connected to its adjacent layer or layers.

[0075] The packaging may comprise a flexible film, and each layer may comprise a flexible film sheet.

[0076] In some embodiments, the outer packaging may comprise peelable and / or detachable layers.

[0077] In some embodiments the irradiation step does not mark or damage the outermost layer of the packaging material. In some embodiments the irradiation step does not mark or damage the innermost layer of the packaging material (i.e. , the layer adjacent to the food item). In some embodiments the irradiation step produces an image on the outermost layer of the packaging which is identical to the image on the food item. In some embodiments the irradiation step produces an image on the outermost layer of the packaging which is identical to the image on the food item but does not mark or damage the innermost layer.

[0078] Detailed Description of the Invention In order that the invention may be more clearly understood embodiments thereof will now be described, by way of example only, with reference to the accompanying drawings, of which:

[0079] Figure 1 illustrates an example of an apparatus and laser set-up for performing the methods of the present invention.

[0080] Figure 2 illustrates a chocolate bar with a photograph and text formed on the surface of the chocolate bar through outer packaging by laser irradiation using a CO2 laser according to the methods of the invention.

[0081] Figure 3 illustrates a chocolate bar (a) with text etched on the surface of the chocolate bar, through polypropylene outer packaging (b) by laser irradiation using a CO2 laser according to the methods of the invention.

[0082] Figure 4 illustrates a chocolate bar (a) with text formed on the surface of a chocolate bar, through polypropylene outer packaging (b) by laser irradiation using a CO2 laser according to the methods of the invention.

[0083] Figure 5 illustrates (a) an etched chocolate bar which has been etched through blue translucent polyester outer packaging, (b) an etched chocolate bar which has been etched through brown translucent polyester outer packaging, (c), an etched chocolate bar which has been etched through green translucent polyester outer packaging, (d) an etched chocolate bar which has been etched through orange translucent polyester outer packaging, and (e) an etched chocolate bar which has been etched through a transparent polyester outer packaging; all by laser irradiation using a CO2 laser according to the methods of the invention.

[0084] Figure 6 illustrates a chocolate bar (a) with a customised image etched on the surface of the chocolate bar, through a translucent polyester outer packaging (b) by laser irradiation using a CO2 laser according to the methods of the invention. Figure 7 illustrates a chocolate bar (a) with a customised image etched on the surface of the chocolate bar, through an opaque polypropylene outer packaging (b) by laser irradiation using a CO2 laser according to the methods of the invention.

[0085] Figure 8 illustrates a chocolate bar with a photograph and logos etched on the surface of the chocolate bar through outer packaging by laser irradiation using a CO2 laser according to the methods of the invention; wherein the chocolate bar has not been subjected to a pre-conditioning step or a post-conditioning step.

[0086] Figure 9 illustrates chocolate bars with drawings, logos and numbers etched on the surface of the chocolate bar through outer packaging by laser irradiation using a CO2 laser according to the methods of the invention; wherein the chocolate bar has not been subjected to a pre-conditioning step or post-conditioning step (a), and wherein the chocolate bar has been subjected to a post-conditioning step (b).

[0087] Figure 1 shows an example of a laser apparatus 1 for performing the methods of the first, second, third and fourth aspects of the invention.

[0088] The laser apparatus 1 comprises a laser generator 14, a beam bender 24 and a focusing lens 18 housed within a laser focusing head 22. The laser focusing head 22 is connected to a nozzle 20.

[0089] A laser beam 16 is generated by the laser generator 14. In use, the laser beam 16 is directed onto a food item 10 by deflection via the beam bender 24 and through the focusing lens 18 and out of the nozzle 20.

[0090] In the embodiment shown in Figure 1 , the laser generator 14 is a CO2 laser. The laser generator 14 has a wavelength of between around 9000-11000 nm.

[0091] The laser apparatus 1 is used in the methods according to this invention to etch an image onto a chocolate surface 11 of a food item 10. The chocolate surface 11 of the food item 10 is covered, all or at least in part, with an outer packaging 12. Upon laser irradiation, the laser beam 16 irradiates a location 15 on the chocolate surface 11 to be marked. To mark the chocolate surface 11 , the laser energy from the laser beam 16 passes through the outer packaging 12 at a location 13 on the outer packaging above the location 15 on the chocolate surface 11 which is irradiated.

[0092] The laser apparatus 1 is used in the methods according to the invention to form text, photographs, logos, and / or personalised designs onto the chocolate surface 11 of the food item 10 through the outer packaging 12. The methods of the invention enable the formation of images comprising a high level of detail on the chocolate surface 11 of the food item 10 and with higher accuracy and / or resolution than conventional methods.

[0093] It is believed that the laser irradiation of the chocolate surface 11 of the food item 10 etches the image onto the chocolate surface 11 as a result of the change to the chocolate microstructure at the location 15 where the laser irradiates the chocolate surface 11.

[0094] The laser apparatus 1 is used for performing the methods according to the invention and is intended for the transmission of laser energy through the outer packaging 12 and onto the chocolate surface 11 of the food item 10 and wherein a clear mark is formed on the chocolate surface 11 without damage to the outer packaging or change to the structural integrity and / or functional integrity of the outer packaging. The laser parameters used in the methods of this invention may be adjusted depending on the type of chocolate surface 11 , the type of food item 10, the type of material comprising the outer packaging 12, and also for the size, level of detail and resolution of the image to be formed.

[0095] Examples 1 to 8 below demonstrate various embodiments of the methods of the invention wherein the material comprising the outer packaging 12 is varied, and wherein the etched image is also varied. Depending on the level of detail of the image, the laser etching process typically takes around 5 minutes to produce the etched image.

[0096] Examples 1 to 8 demonstrate the use of laser apparatus 1 for performing the methods of this invention in which the method comprises a Gantry CO2 laser wherein the laser power is 5.2W, the laser wavelength is around 10600 nm, and the laser etching speed is around 3600 mm

[0097] S'1. The laser etched image has a resolution of 500x500 DPI.

[0098] Examples 1 to 8 below describe methods according to this invention wherein the food item 10 comprises a solid milk chocolate bar. In the following examples, the chocolate surface 11 comprises a fat content of around 30%. However, the methods described in the following examples are also suitable for use with other food items comprising a chocolate surface. The methods described in the following examples may also be suitable for chocolate surfaces comprising white chocolate, dark chocolate, compound chocolate, or plain chocolate with a fat content in the range of around 5-60%.

[0099] Example 1

[0100] Figure 2 shows a food item in the form of a solid milk chocolate bar 110 which has been subject to a method according to this invention wherein a personalised image comprising text 102 and a photograph 103 is formed on a chocolate surface 111 of the chocolate bar 110. This example demonstrates the high resolution and high level of detail of the image formed on the chocolate surface 111.

[0101] The chocolate surface 111 was irradiated by the laser beam 16 at a location 115 on the chocolate surface 111 that is marked. The laser energy passes through a transparent polymeric outer packaging and onto the chocolate surface 111.

[0102] Example 2

[0103] With reference to Figure 3, Example 2 describes a method according to this invention, wherein an image comprising customised text 202 is formed on a chocolate surface 211 of a solid milk chocolate bar 210, as shown in Figure 3(a) wherein said food item comprises an outer packaging 212, as shown in Figure 3(b).

[0104] Although relatively simple in design, the text 202 formed on the chocolate surface 211 is clear and readable.

[0105] The chocolate surface 211 was irradiated by the laser beam 16 at a location 215 on the chocolate surface 211 that is marked. In order to mark the chocolate surface 211 , the laser energy firstly transmits through the outer packaging 212 at a location 213 on the outer packaging above the location 215 of the chocolate surface 211 that was irradiated.

[0106] The outer packaging 212 consists of a polymeric material that covers the entire chocolate surface 211. With reference to Figure 3, the outer packaging 212 is shown separately to the chocolate bar 210 to reveal the etched image on the chocolate surface 211 . In practice, the outer packaging 212 remains covering the chocolate bar 210 according to the method of this invention so as to protect the chocolate bar 210 from the external environment.

[0107] Polypropylene was used as the outer packaging 212 in this example. The outer packaging 212 is black and opaque with a thickness of 0.127 mm. The colour, transparency and thickness are substantially uniform across the entirety of the outer packaging 212.

[0108] With reference to Figure 3(b), the outer packaging 212 has a faint mark at a location 213 of the outer packaging 212 above the location 215 on the chocolate surface 211 that was irradiated. However, there was no significant damage or change to the structural integrity and / or functional integrity of the outer packaging and was deemed to still provide the desired barrier properties to protect the food item. The damage to the outer packaging was tested using various techniques such as reflected light microscopy, scanning electron microscopy (SEM), oxygen transition radiation (OTR) and water vapour transmission rate (WVTR). All aforementioned techniques showed that there were no major differences observed between etched and unetched areas of the outer packaging.

[0109] Example 3

[0110] With reference to Figure 4, Example 3 describes a method according to this invention, wherein an image comprising customised text 302 is formed on the chocolate surface 311 of a solid milk chocolate bar 310, as shown in Figure 4(a) comprising an outer packaging 312, as shown in Figure 4(b).

[0111] The text 302 etched on the chocolate surface 311 is not as clear as the text etched in Example 2. The chocolate surface 311 was irradiated by the laser beam 16 at a location 315 on the chocolate surface 311 that is marked. In order to mark the chocolate surface, the laser energy firstly passes through the outer packaging 312 at a Iocation313 on the outer packaging above the location 315 where the chocolate surface 311 was irradiated.

[0112] The outer packaging 312 consists of a polymeric material that covers the entire chocolate surface 311 . As in Example 2, and with reference to Figure 4, the outer packaging 312 is shown separately to the chocolate bar 310 to reveal the etched image on the chocolate surface 311 . In practice, the outer packaging 312 remains covering the chocolate bar 310 according to the method of this invention so as to protect the chocolate bar 310 from the external environment.

[0113] As with Example 2, polypropylene was used as the outer packaging 312 in this example. However, the outer packaging 312 used herein is white and translucent with a thickness of 0.45 mm. The colour, transparency and thickness are substantially uniform across the entirety of the outer packaging 312.

[0114] With reference to Figure 4(b), the outer packaging 312 has a very faint mark at a location 313 on the outer packaging 312 above the location 315 on the chocolate surface 311 that was irradiated. However, there was no significant damage or change to the structural integrity and / or functional integrity of the outer packaging. The marking to the outer packaging is visibly less than that of Example 2.

[0115] Example 4

[0116] With reference to Figure 5, Example 4 describes a method according to this invention, wherein an image comprising customised text 402 is formed on the chocolate surface 411 of a solid milk chocolate bar 410, as shown in Figures 5(a) to 5(e) comprising an outer packaging (not shown).

[0117] Figures 5(a) to (e) show very good clarity and high resolution of the text 402 formed on the chocolate surface 411 of the chocolate bar 410.

[0118] The chocolate surface 411 was irradiated by the laser beam 16 at a location 415 on the chocolate surface 411 that is marked. In order to mark the chocolate surface, the laser energy firstly passes through an outer packaging. The outer packaging is not shown in Figure 5. However, the method of etching the chocolate surface 411 through the outer packaging occurs in a similar process as described in Examples 2 and 3.

[0119] The outer packaging consists of a polymeric material that covers the entire chocolate surface 411. In comparison to Examples 2 and 3, polyester was used as the outer packaging material in this example. The outer packaging materials used in this example were translucent materials. Example 4 demonstrates the use of the method of this invention with outer packaging materials comprising various colours. Referring to Figure 5, the following colours of outer packaging were used; (a) blue, (b) brown, (c) green, (d) orange and (e) clear. For (a) to (e), the outer packaging had the following thickness; (a) 0.06 mm, (b) 0.14 mm, (c) 0.09 mm, (d) 0.12 mm, (e) 0.14 mm. For (a) to (e), the colour, transparency and thickness are substantially uniform across the entirety of each outer packaging.

[0120] The results show that changing the colour of the outer packaging material does not affect the quality of the etched image and so it is believed that any coloured outer packaging may be used in the methods of this invention.

[0121] The outer packaging incurred minimal marking by the laser irradiation process. Any minor marking to the outer packaging was not clearly visible by eye. Comparing this result with the previous examples, it is believed that thinner and / or translucent materials result in less or no marking to the outer packaging.

[0122] Example 5

[0123] With reference to Figure 6, Example 5 describes a method according to this invention, wherein an image comprising a quick response (QR) code 504 is formed on the chocolate surface 511 of a solid milk chocolate bar 510, as shown in Figure 6(a) comprising an outer packaging 512, as shown in Figure 6(b).

[0124] Example 5 demonstrates the laser etching of an image with a higher level of detail compared to the text formed in Examples 2 to 4. The image 504 etched is clear and of good resolution. The chocolate surface 511 was irradiated by the laser beam 16 at a location 515 on the chocolate surface 511 that is marked. In order to etch the chocolate surface, the laser energy firstly passes through the outer packaging 512 at a location 513 on the outer packaging above the location 515 where the chocolate surface 511 is irradiated.

[0125] The outer packaging 512 consists of a polymeric material that covers the entire chocolate surface 511 . As in Example 2 and 3, and with reference to Figure 6, the outer packaging 512 is shown separately to the chocolate bar 510 in order to reveal the etched image on the chocolate surface 511. In practice, the outer packaging 512 remains covering the chocolate bar 510 according to the method of this invention so as to protect the food item from the external environment.

[0126] As with Example 4, polyester was used as the outer packaging 512 in this example. Example 5 demonstrates the use of a method of this invention with outer packaging 512 materials of a greater thickness than Example 4. The outer packaging 512 has a thickness of 0.41 mm. The outer packaging 512 used in this example is a red translucent material. The colour, transparency and thickness are substantially uniform across the entirety of the outer packaging 512.

[0127] The outer packaging 512 incurred no significant marking or no change to the structural integrity and / or functional integrity by the laser irradiation process.

[0128] Example 6

[0129] With reference to Figure 7, Example 6 describes a further method according to this invention, wherein an image comprising a quick response (QR) code 604 is formed on the chocolate surface 611 of a solid milk chocolate bar 610, as shown in Figure 7(a) comprising an outer packaging 612, as shown in Figure 7(b).

[0130] As with Example 5, Example 6 demonstrates the laser etching of an image 604 on a chocolate surface 611 with a higher level of detail compared to the text in earlier examples. Example 6 shows that the image 604 is only partially formed through the outer packaging 612. The image is of lower quality compared to the similar image formed in example 5. However, although of lower quality, the image is clearly visible on the chocolate surface 611 . The chocolate surface 611 was irradiated by the laser beam 16 at a location 615 on the chocolate surface 611 that is marked. In order to mark the chocolate surface, the laser energy firstly passes through the outer packaging 612 at a location 613 on the outer packaging above the location 615 where the chocolate surface 611 is irradiated.

[0131] The outer packaging 612 consists of a polymeric material that covers the entire chocolate surface 611 . As in Examples 2, 3 and 5, and with reference to Figure 7, the outer packaging 612 is shown separately to the chocolate bar 610 in order to reveal the etched image on the chocolate surface 611. In practice, the outer packaging 612 remains covering the chocolate bar 610 according to the method of this invention so as to protect the food item from the external environment.

[0132] Polypropylene was used as the outer packaging 612 material in this example. The outer packaging 612 used in this example is a black transparent material with a thickness of 0.127 mm. This is the same outer packaging used in Example 1 . The colour, transparency and thickness are substantially uniform across the entirety of the outer packaging 612.

[0133] Referring to figure 7(b), the outer packaging 612 has incurred slight marking to the outer packaging but no change to the structural integrity and / or functional integrity. However, there was no significant damage or change to the structural integrity and / or functional integrity of the outer packaging by the laser irradiation process.

[0134] In Examples 1 to 6, or in other embodiments of the methods of the invention, the food items may be subject to a pre-conditioning step prior to laser irradiation. Alternatively, the food items may be subject to a post-conditioning step following laser irradiation. Examples 1 to 6 show food items that have been subject to both a pre-conditioning step and a post-conditioning step.

[0135] Hot air conditioning steps were used in Examples 1 to 6. The pre-conditioning step used in Examples 1 to 6 comprised one step wherein the wrapped food item is placed in a temperature-controlled environment of 20 °C for a time of around 12 hours. It may be that the pre-conditioning step comprises a time longer than 12 hours, or less than 12 hours, without affecting the quality of the image formed. A post-conditioning step directly follows the laser irradiation process. The postconditioning step used for Examples 1 to 6 comprises of two steps. The first post-conditioning step comprises placing the wrapped food item in a temperature-controlled environment of 25 °C for 17 hours. The second post-conditioning step comprises placing the wrapped food item in a temperature controlled environment of 16 °C for 5 hours. Again, the post-conditioning times vary without affecting the quality of the image formed.

[0136] The following Examples 7 and 8 describe methods of this invention without preconditioning and / or post-conditioning steps.

[0137] Example 7

[0138] With reference to Figure 8, Example 7 describes a further method according to this invention, wherein images comprising logos 705 and photographs 703 are formed on the chocolate surface 711 of a solid milk chocolate bar 710.

[0139] As with the previous examples, the laser etching method comprises irradiating the chocolate surface 711 of a chocolate bar 710 through an outer packaging (not shown) using a CO2 laser. However, the chocolate bar of Example 7 has not been subject to a pre-conditioning step, or a post-conditioning step.

[0140] Example 8

[0141] With reference to Figure 9, Example 8 describes a method according to this invention, wherein images comprising drawings 806, shapes 807, numbers 808 and logos 805 are formed on the surface of a solid milk chocolate bar.

[0142] As with the previous examples, the laser etching method comprises irradiating the chocolate surface 811 of the chocolate bar 810 through an outer packaging (not shown) using a CO2 laser.

[0143] Example 8 demonstrates, two laser etching methods according to this invention wherein laser etched chocolate bars comprise the same laser etched image. The first method does not comprise a pre-conditioning step nor a post-conditioning step, Figure 9(a).

[0144] In comparison, in a second method, the chocolate bar is subjected to a post-conditioning step, Figure 9(b). The post-conditioning step comprises one step in which the chocolate bar is placed in a temperature-controlled environment of 25 °C overnight.

[0145] Example 8 demonstrates that a post-conditioning step improves the quality and clarity of the laser etched image.

[0146] The above embodiments are described by way of example only. Many variations are possible without departing from the scope of the invention as defined in the appended claims.

Claims

CLAIMS1. A method of forming an image on a surface of a food item having an outer packaging, wherein the food item comprises a chocolate surface, the method comprising the step of irradiating the chocolate surface of the food item at one or more locations using a laser to form an image thereon; wherein the step of irradiating the chocolate surface comprises passing laser energy through the outer packaging and onto the chocolate surface of the food item at the one or more locations, and wherein the laser has a wavelength of around 7000 nm to 22000 nm.

2. A method as claimed in claim 1 , wherein the laser wavelength is between 9000 nm to 11000 nm.

3. A method as claimed in claim 1 or 2, wherein the laser wavelength is around 10600 nm.

4. A method of forming an image on a surface of a food item having an outer packaging wherein the food item comprises a chocolate surface, the method comprising the step of irradiating the chocolate surface of the food item at one or more locations using a laser to form an image thereon; wherein the step of irradiating the chocolate surface comprises laser energy passing through the outer packaging and onto the chocolate surface of the food item at the one or more locations, and wherein the laser is a CO2 laser.

5. A method as claimed in any one of claims 1 to 4, wherein the outer packaging comprises a material selected from a group consisting of: polymeric material, paper, paperboard, cardboard, cork, ceramic, food, leather, rubber, silicon, stone, granite, marble, textiles, wood, metal, glass, or a combination of the aforementioned.

6. A method as claimed in any preceding claim, wherein the outer packaging comprises a polymeric material.

7. A method as claimed in any preceding claim, wherein the laser power is at least 1 W and no more than 9W.

8. A method as claimed in any preceding claim, wherein the laser etching speed is greater than 800 mm s1and no more than 75000 mm s1.

9. A method as claimed in any preceding claim, wherein the laser etched image has a resolution of around 20-3000 Dots Per Inch (DPI).

10. A method as claimed in any preceding claim, wherein laser irradiation through the outer packaging does not result in any significant damage or change to the structural integrity and / or functional integrity of the outer packaging and wherein an image is etched on the chocolate surface of the food item.

11. A method as claimed in any preceding claim, wherein the outer packaging comprises an opaque material above the location of the chocolate surface of food item which is irradiated.

12. A method as claimed in any preceding claim, wherein the outer packaging comprises a translucent material above the location of the chocolate surface of the food item which is irradiated.

13. A method as claimed in any preceding claim, wherein the outer packaging comprises a transparent material above the location of the chocolate surface of the food item which is irradiated.

14. A method as claimed in any one of claims 11 to 13, wherein the outer packaging is coloured above the location of the chocolate surface of the food item which is irradiated.

15. A method as claimed in any preceding claim, wherein the outer packaging has a thickness of no more than 10 mm, or preferably no more than 0.55 mm above the location of the chocolate surface of the food item which is irradiated.

16. A method according to any preceding claim, wherein the chocolate surface of the food item comprises a white chocolate, milk chocolate, plain chocolate, compound chocolate, dark chocolate surface or any combination thereof, optionally comprising inclusions.

17. A method according to any preceding claim, wherein the chocolate surface of the food item has a fat content of at least 5% and no more than 60%.

18. A method of forming an image on a surface of a food item having an outer packaging, wherein the food item comprises a chocolate surface, the method comprising the step of irradiating the chocolate surface of the food item at one or more locations using a laser to form an image thereon; wherein the step of irradiating the chocolate surface comprises laser energy passing through the outer packaging and onto the chocolate surface of the food item at the one or more locations, and wherein the method may further comprise one or both steps of pre-conditioning the food item and post-conditioning the food item.

19. A method as claimed in claim 18, wherein the pre-conditioning step and / or postconditioning step comprises a heat conditioning step where the food item is heated directly, a hot air conditioning step where the food item is placed in a temperature controlled environment, a microwave conditioning step, or an infrared conditioning step.

20. A method as claim in claim 18 or 19, wherein the pre-conditioning step and / or postconditioning step comprises one or more than one steps, wherein each step may comprise placing the wrapped food item in a temperature-controlled environment at a set temperature for a length of time.21 . A method of forming an image on a surface of a food item having an outer packaging, wherein the food item comprises a chocolate surface, the method comprising a step of forming the image by using a laser to change the fat microstructure and / or fat content at one or more locations on the chocolate surface through irradiating the chocolate surface of the food item at the one or more locations to form the image thereon; wherein the step of irradiating the chocolate surface comprises laser energy passing through the outer packaging and onto the chocolate surface of the food item at the one or more locations.

22. A method of forming an image on a surface of a food item having multiple layers of outer packaging, wherein the food item comprises a chocolate surface, the method comprising the step of irradiating the chocolate surface of the food item at one or more locations using a laser to form an image thereon; wherein the step of irradiating the chocolate surface comprises laser energy passing through the multiple layers of outer packaging and onto the chocolate surface of the food item at the one or more locations.

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