A METAL MATERIAL, EDIBLE AND FLAVOURED,

AND A PROCESS FOR ITS PREPARATION

DESCRIPTION

Field of the Invention

The present invention relates in general to the field of food preparations, and more particularly it refers to a metal material, edible and flavoured, and to the related process of preparation.

State of the Art

The use of precious metals, in particular of gold and silver, for the decoration of food and drinks is known since ancient times and in all parts over the globe, from the ancient Japan to the pre-Columbian cultures of South America. In the 16 ^th century it seems that gold was so widely used for cooking that the authorities in some countries even decided to regulate the use with the limitation to special occasions, and without exceeding a definite quantity. Of course its use in different past eras has remained limited to kings and queens, or however to great dignitaries who could afford such a luxury.

The use of gold and silver for cooking was then re-launched a few decades ago, no longer as a luxury for the few, but rather as a product for everyone, great-looking and responsive to the increasingly widespread demands of a high level gastronomy. In fact, the edible precious metals, and in particular gold, that have any kind of reactivity, do not alter the flavour of foods and beverages to which are added, while they give a unique appearance to any dishes, ennobling even the most simple food, and therefore their use has spread widely. On the market products may be found in particular in the form of thin sheets, powder or flakes of edible gold, which has a carat weight generally comprised between 22 and 24 kt.

From the legislative point of view, gold and silver edible products are classified as food dyes, referred to as E-175 and E-174, by a directive of 30 June 1994, Directive No. 94/36/EC of the European Parliament, subsequently updated by EC Regulations 1333/2008 and CE231/2012, and its use in foods is governed by EC Regulation 1 129/2012 and guaranteed by International food certifications like any other food products with no contraindications for human health.

Generally, the edible precious metals are produced and sold in very thin sheets or in shredded forms, such as powder, crumbs or flakes, which are applied directly to food or even on the plate or in the glass as a decoration. The only precaution to have for the application of these products is to always use tweezers to remove the product from its packaging and to place it, without touching it directly with the fingers, because moisture on the skin would attach the metal foil to the skin, thus making it unusable. Edible gold and silver also fear in general the moisture and must be stored in a suitable environment, which means mainly in a dry environment.

It is therefore evident how such metal products in sheets or in shredded form are extremely fragile and up to date, at least as far as the Applicants are aware of, any attempts to apply aromatic substances to these sheets in order to also make pleasant their flavour, have failed.

Methods have been developed, for example, for the application of aromatic substances by spraying of their solutions or suspensions directly onto the surface of the metal sheets. It was noted, however, that the aroma was present and effective only until the surface was wet and therefore unusable for the application as mentioned above, while after evaporation, the olfactory effect was totally ineffective.

Another attempt has been made by applying to the surface of the metal sheet an aqueous formulation of the aromatic substance with maltodextrin and gum arabic, followed by evaporation. Even in this case, the attempts have proved unsuccessful: the evaporation in ventilated rooms cannot be carried out in fact because of the lightness of the metal sheets, which would fly everywhere; the evaporation in static rooms, however, even if feasible and able to yield the dried product, also evaporates the aroma, thus making it totally ineffective its application; finally, the removal of water by lyophilisation is a rather effective method in particular in respect of the maintenance of the aromatic substance properties, but the final product was also in this case unsatisfactory, because with the lyophilisation the typical gloss of gold was completely lost.

As far as the Applicants are aware of, up to today have not been developed processes for preparing edible precious metal in sheet form, that are also flavoured with flavouring substances for food use, and that solve the drawbacks of the known procedures discussed above.

Summary of the invention

Now the Applicants have found a process of preparation to obtain, by an easily scalable procedure also at industrial scale, edible precious metals in the form of sheets, which overcome the problems highlighted above for the known processes by managing to produce a flavoured metal in sheets, which keeps the characteristic sheen of the precious metal and adds to it the flavour of the flavouring substances from time to time used. Thanks to its characteristics, the novel precious metal in the form of sheets is suitable for use in foodstuff, not only as a decorative element but also as a flavouring element, and therefore as a proper ingredient.

It is therefore a subject of the invention a process for the preparation of a precious metal material, edible and flavoured, as defined in the first of the attached claims.

A precious metal material, edible and flavoured, and the use thereof as food products, as defined in the independent claims 11 and 13, are a further subject of the invention.

Further important features of the process of preparation of the precious metal material flavoured in sheet form, and of the material itself, as well as of the use thereof according to the invention, are defined in the dependent claims here attached, and reported in the following detailed description.

Detailed description of the invention

In the present invention by the term "precious metal" a precious metal is meant that is edible and suitable to be processed in sheets, selected for instance in the group consisting of gold, silver, and respective alloys thereof possibly with copper, always in respective combinations and concentrations allowed by the food regulations in force.

Examples of edible precious metals of possible use according to the invention are the gold dye E-175, consisting of an alloy of gold (minimum content≥ 90%), silver (maximum content≤ 7%), and copper (maximum content≤ 4%), and the silver dye E- 174 consisting of silver in amount≥ 99.5%.

Gold, silver and alloys thereof are the precious metals typically used to accomplish the invention. According to a particularly preferred embodiment of the invention, the precious metal is an alloy of gold and silver that meets the definition of gold dye E-175 above mentioned.

According to the invention by "flavouring substance" any compounds is meant, or mixture of compounds, suitable for food use and having a pleasant smell and/or taste, which enhances or gives a characteristic aroma to the food or beverage to which it is added. Such substances are in accordance with the CE Regulation No. 1334/2008 of the European Parliament and Council of December 16th 2008 concerning aromas and some food ingredients having flavouring properties intended for use in and on food, and that amend the CEE Regulation No. 1601/91 of the Council, the CE Regulations No. 2236/96 and CE No. 1 10/2008 and the 2000/13/CE Directive.

By way of a non-limiting example of the present invention, flavouring substances of possible use are the following: peppermint, coconut, eggnog, coffee, chocolate, hazelnut, orange, lemon, cola, tropical, raspberry, lime, vanilla, Madagascar vanilla berries extract, strawberry, rosemary, olive oil, garlic, onion, sage, asparagus, black truffles, white truffles, butter, black pepper, chilli pepper, saffron. Preferred flavouring substances according to the invention are selected from among lime, Madagascar vanilla berries extract, white truffles and olive oil.

In the process of the invention synthetic flavouring substances or natural flavouring substances can be used, the latter representing a preferred embodiment of the invention.

The process of preparation of a precious metal material edible and flavoured according to the invention comprises the following steps:

i) preparation of a solution of shellac in a suitable solvent, further comprising a flavouring substance;

ii) application of the solution prepared in step i) on the surface of an edible, precious metal sheet material;

iii) drying of the metal material, on which the solution is applied, obtained in step ii). Shellac is a polymer of natural origin, with a chemical composition similar to that of synthetic polymers, which has been found surprisingly able to create a protective layer of flavourings applied on thin sheet metals, without altering the characteristics of the metal sheet itself, in particular its colour and sheen; it can also be applied easily and without damaging the metal foil, as on the contrary is for other products, even similar, such as gum arabic.

Shellac is a lac purified and bleached, obtained from the resinous secretion of an insect, called Laccifer lacca, whose use is governed by EU Regulation No. 231/2012. That regulation, which classifies the shellac as a food additive E-904, also defines their criteria of purity in terms of weight loss on drying, which must be less than 6% by weight at 40°C after 15 hours on silica gel, in terms of quantity of wax and lead content. Preferably, the shellac used in the present process is dewaxed, namely it has a content of wax lower or equal to 0.2% by weight.

Solvents suitable for use in step i) of the process of the invention are selected amongst the solvents of shellac that may be used for food stuff for the use with aromas. Examples of suitable solvents are ethyl acetate, benzyl alcohol, n-propyl alcohol, i- propyl alcohol and ethyl alcohol. According to a preferred embodiment of the present invention, the solvent is ethyl alcohol.

Suitable solutions for use in the present process are for instance shellac solutions obtained by dissolving shellac flakes or powder in the minimum amount of solvent required to dissolve completely the shellac. The shellac concentration in the present solutions will be for instance comprised between 1 and 60% by weight with respect to the total weight of the solution, and preferably it will be comprised between 20 and 35% by weight.

To the so obtained shellac solution the selected flavouring substance is then added, in the form of powder or in liquid form, and it is mixed until complete dissolution; alternatively the flavouring substance may be added already dissolved in the same solvent wherein the shellac was dissolved. The amounts of flavouring substance added from time to time determined by any technician expert in the field depending on the type of flavouring substance and on the effect that you may want to obtain in terms of kind and intensity of the aroma.

According to a particular embodiment of the invention the flavoured metal material prepared as described above may further comprise one or more food additives selected for instance in the group consisting of antioxidants, colouring agents, stabilizers, thickeners, preservatives, sweeteners, and mixtures thereof; such additives may be added to the shellac solution in step i) of the present process.

The application of the solution to the metal sheet may be accomplished on a part or on more selected parts of one or both surfaces of the sheet or, preferably, on the whole surface of one or of both sides of the sheet. Such application in step ii) of the present process may be carried out by mechanical action, for instance by brushing or spraying the solution on the metal sheet, or even by immersion of the sheet into the solution; alternatively, the application can be made with chemical-physical means, for example by nebulizing the solution on the metal sheet.

According to a particularly preferred embodiment of the present process, the application of the solution is carried out by the use of a suitable vaporizer/nebulizer; as a matter of fact such technique allows moving minimum masses of air so that the metal sheet remains perfectly stationary and stable during the operation.

Also the drying step iii) can be carried out alternatively by mechanical methods, such as natural ventilation or drying with a hot, forced-air flow, or by chemical-physical methods, such as lyophilisation, until complete evaporation of the solvent from the solution and obtainment of a dry layer of shellac and flavouring substance. For an optimal drying at room temperature too, both in terms of efficacy and of rapidity, it is preferable to use ethyl alcohol as solvent for the preparation of the solution; ethyl alcohol is among other things perfectly suitable for food use and guarantees the complete solubility of shellac, and in particular the ethyl alcohol 96° so called "buongusto". Typically the time of air drying of the solution according to the present process may range between 2 and 5 hours, depending on the amount of solution applied on the metal surface.

The so obtained final product consists of a precious metal material in the form of a sheet comprising on one or on both surfaces at least a layer of shellac, with a flavouring substance "trapped" inside said layer. The layer of shellac and flavouring substance is perfectly transparent, and does not alter in any way the colour or the sheen of the underlying metal, being at the same time always able to spreading odours and/or flavours typical of the flavouring substance according to its natural characteristics, that the present process does not alter at all. When the product, at the time of use, is put into contact with food, many factors allow the release of odours and/or flavours from the flavoured products, such as the heat, the liquids possibly present in the dish, the enzymes of the saliva, and the same mechanical action of chewing.

According to a particular embodiment of the present process, after drying in step iii) a further layer of a shellac solution, this time without the flavouring substance, may be applied over the first dry layer of shellac, so as to form a further protective layer of the underlying aromas. Such application of a second layer can be accomplished as already described above for the application of the first layer, and it is followed by a drying step, again carried out as described above for the step iii) of drying of the first layer. The final product obtained will have in this case two layers of shellac, the first in contact with the metal also comprising the flavouring substance. Also in this case the shellac does not alter the aspect of the metal sheet nor the ability of aroma to spread on food and drinks at the time of use.

The precious metal material in the form of sheets obtained by the present process may be then possibly shredded or cut into regular shapes, before being packaged for the subsequent sale.

It can be used for colouring ad decorating food and drinks, further giving to foodstuff where it is added the smell and/or taste of the flavouring substance contained therein, that keeps perfectly intact thanks to the protective layer created by the present process.

The following non-limiting examples are reported to illustrate the present invention. EXAMPLE 1

Preparation of a shellac solution

In a suitable container the following ingredients have been poured: 2 g of lime essential oil, 30 g of shellac E-904, and ethyl alcohol 96° until complete dissolution of the shellac, without heating and under stirring.

The so obtained solution was filtered on filter paper before use.

EXAMPLE 2

Application of the solution on a gold leaf The gold leaf was placed on a non-stick surface then the solution prepared in Example 1 was uniformly distributed in a thin layer on the gold leaf by mechanical micronisation. The application of the same solution of Example 1 on the gold leaf was repeated also by nebulization with compressed air.

EXAMPLE 3

Drying

The gold leaf with the solution applied as in Example 2 was allowed to dry in air with a natural system of ventilation until the solvent was completely evaporated, and the surface of the leaf was perfectly dry after a time period of about 4 hours.

EXAMPLE 4

Characterization of the final product

The characteristics of manageability of the product in leaf, processed and dried as described in the previous Examples, were improved compared to those of the starting gold leaf, thanks to the presence of the dry residue of the shellac and the aroma which there has been deposited thereon and which advantageously makes the leaf more rigid.

It was however observed that the increased stiffness of the gold leaf was not going to minimally affect its characteristics of applicability on foodstuff and the ability to blend with food or to be added in beverages.

Likewise, as regards to the sheen, it was wholly similar in the starting gold leaf and in the gold leaf with shellac and aroma applied on the surface.

The gold leaf flavoured with the lime essence prepared in the Examples above was added to various types of liqueurs and alcoholic beverages to obtain cocktails with lime flavour, having at the same time an original effect due to gold fragments fluctuating in the drink. The gold leaf with lime flavour was also applied on chocolate giving to it, besides the gold glistening appearance, also the fresh tone, slightly sour, of the lime. The finished product obtained with the process of the invention proved therefore to be able to combine the decorative features of the gold leaf and the aroma of the essence applied thereon for a very pleasant stimulation of both sight and taste.

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The present invention has been described herein with reference to preferred embodiments thereof. It is understood that there may be other embodiments afferent to the same inventive core, all falling within the protective scope of the claims set out below.