GB2186782A

GB2186782A - An edible ink and a method of printing onto an edible substrate using same

Info

Publication number: GB2186782A
Application number: GB08704130A
Authority: GB
Inventors: Stuart Michael Bell; David Robinson
Original assignee: BIGIN MARKETING Ltd
Current assignee: BIGIN MARKETING Ltd
Priority date: 1986-02-22
Filing date: 1987-02-23
Publication date: 1987-08-26
Anticipated expiration: 2007-02-23
Also published as: GB2186782B; GB8704130D0

Abstract

A sheet of an edible substrate has on it an image printed in an edible ink. The edible ink is comprised of an aqueous solution or paste the vapour pressure of which is less than the partial vapour pressure of water in the edible substrate at normal atmospheric pressure. The edible ink may comprise a sucrose solution containing 90 grams sucrose, 10 grams water, together with artificial colouring and flavouring. The device may be used in advertising a food product that includes the "image" item.

Description

SPECIFICATION An edible ink and a method of printing onto an an edible substrate using same The present invention relates to an edible item and, in particular, to an edible substrate on which images of, for example, food products are printed in an edible ink. The present invention also relates to an edible ink for use in printing images onto an edible substrate. The present ivention further relates to a method of printing onto an edible substrate using edible inks. By edible it is meant that the material is safe for human consumption.

Promotional campaigns are often used to bring new food products to the attention of the public. Usually such campaigns involve giving away samples of the product at supermarkets and stores. This is expensive for the promoter in that special runs of the product must be made for the promotions and people hired to distribute the product and assess public reaction to it. Moreover, such campaigns have little novelty value and their impact on the public is limited to those supermarkets and stores where samples of the product are being tested.

For some time past now it has been a wish of many food manufacturers and advertisers to be able to promote new, and indeed, existing food products using images of the product printed on edible paper. These printed images would ideally look, taste and possibly smell like the food product so as to capture the interest of the public in them, and could easily and cheaply be distributed by inserting them in magazines and papers.

Of course, the obvious choice of edible substrate onto which images of a product could be printed is "rice" paper , but conventional coloured water based inks swell the fibres of "rice" paper and give rise to an effect known as "cockling". This cockling effect distorts the "rice" paper even after is has dned out, and this results in bad definition for the printed images. In addition, there is a tendency for the different coloured and flavovred inks to run together when printed in close proximity on the "rice" paper.

It is an object of the present invention to provide an edible substrate on which an image of, for example, a food product is printed in edible ink, in which the aforementioned problems are obviated or substantially mitigated.

It is a further object of the present invention to provide an edible ink which can be used on "rice" paper and other edible substrates which does not tend to dissolve then and give rise to the effect known as "cockling".

It is yet another object of the present invention to provide a method of printing on to an edible substrate using edible ink.

According to a first aspect of the present invention there is provided a sheet of an edible substrate on which an image is printed in an edible ink, wherein the edible ink is comprised of an aqueous solution or paste the vapour pressure of which is less than the partial vapour pressure of water in the edible substrate at normal atmospheric pressure.

According to a second aspect of the present invention there is provided an edible ink for use in printing on an edible substrate comprised of an aqueous solution or paste the vapour pressure of which is less than the partial vapour pressure of water in the edible substrate at normal atmospheric pressure.

Preferably, the aqueous solution or paste comprises a saturated solution of a sugar of such concentration that when exposed to normal atmospheric pressure it sets by precipitation of a crystalline matrix to a solid with a non-tacky surface. The sugars used may be simple or complex and appropriate selection allows the flavour of the ink to be subtly varied. The vapour pressure of the solution or paste is determined by the number of molecules in solution, however in a preferred embodiment of the present invention the aqueous solution or paste comprises nine parts sucrose to one part water, by weight.

The inventors believe that the cockling effect seen when water is applied to a substrate, particularly a "rice" paper substrate, is caused by the rapid absorption of water into the substrate resulting in the fibres swelling uncontrollably.

In the present invention, however, the vapour pressure of moisture in the solution or paste is less than that of moisture in the substrate and so there is differential between the two materials which tends to encourage moisture to pass from the paper to the solution or paste.

Of course depression of the vapour pressure slows down the evaporation of moisture from the surface of the applied solution or paste but it is important that the solution or paste sets to a nontacky solid after application. This solid need not be rigid and may deform to the touch but should not be transferred when touched. An effect equivalent to drying can be obtained by choosing an ingredient, for for example a sucrose solution as referred to above, which cakes at the surface of the paste following its application to the paper. In the case of caking by crystallisation the effect depends on humidity as well as saturation.

The structure of the crystallisation can be modified with additives, for example the alginate used in ice cream.

Hardening of the deposited solution or paste may be achieved by a mechanism other than the precipitation of crystals at the surface. For example by the formation of a gel using e.g.

gelatin, pectin or albumen, or maybe thixotropic additives. The possibility of a reactive hardening system should not be forgotten for example when a solution of sodium alginate comes into contact with calcium chloride, calcium alginate is formed which is a solid. The effect might be achieved with a powder dusting technique.

Preferably, artificial or natural food colourings and food flavourings are used in the solution. These artificial or natural food colourings and food flavourings are usually designated by either an E number or a serial number and are readily available in the food industry. Where the images to be printed are of foodstuffs the colours and flavourings used in the edible inks can be matched to those of the real foodstuff.

"Rice" paper is an ideal choice for printing on with the edible ink of the present invention. However, other edible, that is water soluble or water absorbing films and papers may be used instead.

It has been found that images of food products printed on a substrate in the edible ink of the present invention do not dissolve the substrate and give excellent image definition.

The artificial and natural food colourings and food flavourings accurately reflect the tastes of many natural foods, and, by way of example, images tasting of chocolate, orange and savoury foodstuffs have been printed on rice paper in the applicant's trials.

Preferably, the edible ink according to the second aspect of the present invention is printed onto an edible substrate using conventional screen printing techniques.

This method of printing may be repeated, using differing stencils for each coloured and flavoured ink to be used on the edible substrate. Thus the final sheet of edible substrate may protray on it a picture of a complete meal, each part of which has its own distinctive colouring and flavouring. This has tremendous practical implications for those seeking to promote a new food product, as it may be portrayed in a variety of meal settings, each one of which actually tastes as it looks.

Other printing techniques may also be used, although the effectiveness of these remain to be evaluated by the inventors.

Once an image is printed on an edible substrate, particularly "rice" paper it must be ailowed to dry before the next image can be printed. In order to prevent the sheets of edible substrate from sticking together a layer of powder, such as cornflower, may be sprinkled between them. As the edible ink used to print the images is comprised of a saturated car bohydrate solution it tends to dry very quickly. The speed at which it dries is increased if thicker films or papers are used and in some instances it may be possible to dispense with the layer of separating powder.

An embodiment of the present invention will now be described, by way of example, with reference to the accompanying drawings, in which: Fig. 1 shows a screen printing apparatus for use in the present invention; and Fig. 2(a), (b) and (c) illustrate three separate stages in the development of multi-coloured and multiflavoured images.

Referring to Fig. 1 of the accompanying drawings there is shown a screen printing press 1 for printing images in edible ink onto an edible substrate, such as "rice" paper. The press comprises a table 2 which supports a sheet of "rice" paper 3. Over the "rice" paper 3 a stencil 4 is placed in which the shapes 5 of images to be printed in a particular flavour and colour have been cut out. Over the stencil 4 a mesh screen 6 is positioned, the sides 7 of which define a tray into which edible ink can be poured. Usually the mesh screen 6 and the stencil 4 will be formed as a single unit, but they have been shown separately in the drawing for the sake of clarity.

Once the ink has been poured over the mesh screen 6 a flexible squeezing blade 8 is used to force the ink through the mesh screen 6.

The blade 8 is swept over the mesh screen 6 and ensures an even distribution of ink through the mesh screen 6. Those areas of the "rice" paper 3 which are not covered by the stencil are impregnated with the ink.

The edible ink is comprised of a saturated solution of sugar which is coloured with artificial food colourings and flavoured with artificial food flavourings. It is essential that the ink sets to allow further printing steps to be made and also to ensure that the "rice" paper does not dissolve and in this respect it has been found that a sucrose solution containing 90 grams of sucrose to 10 grams of water gives very good results.

As soon as a printing step is completed the sheet of "rice" paper 3 may be allowed to set on a rack. To prevent it sticking to adjacent sheets a fine layer of cornflour may be sprinkled between the sheets as they are laid one on top of the other.

Referring now to Figs. 2(a), (b) and (c) it can be seen how a number of different coloured and flavoured food products are printed on a sheet of "rice" paper. As shown in Fig.

2(a) a representation of a sausage 9 is printed first. Then, as shown in Fig. 2(b) a representation of an egg white 10 is printed. Finally, as shown in Fig. 2(c) a representation of an egg yolk 11 is printed. Thus, the final picture is of egg and sausage, and each part of the image has its own unique and distinctive colour and flavour.

Claims

1. A sheet of an edible substrate on which an image is printed in an edible ink, wherein the edible ink is comprised of an aqueous solution or paste the vapour pressure of which is less than the partial vapour pressure of water in the edible substrate at normal atmospheric pressure.

2. A sheet according to claim 1, wherein the edible substrate is comprised of a water soluble material.

3. A sheet according to claim 2, wherein the water soluble material comprises rice paper.

4. An edible ink for use in printing on an edible substrate comprised of an aqueous solution or paste the vapour pressure of which is less than the partiai vapour pressure of water in the edible substrate at normal atmospheric pressure.

5. An edible ink according to claim 4, wherein the aqueous solution or paste comprises a saturated solution of a sugar.

6. An edible ink according to claim 5, wherein the aqueous solution or paste comprises nine parts sugar to one part water, by weight.

7. An edible ink according to any one of claims 4, 5 or 6 in which the solution or paste sets by crystallisation on its surface.

8. An edible ink according to claim 7, in which the structure of crystallisation of the solution or paste is modified by additives.

9. An edible ink according to any one of claims 4, 5 or 6, in which hardening of the solution or paste may be achieved by a mechanism other than the precipitation of crystals at the surface.

10. An edible ink according to claim 9, in which the hardening mechanism comprises a gel forming agent.

11. An edible ink according to any of claims 4 to 11 wherein artificial or natural food colourings and food flavourings are used in the solution or paste.