OBJECT OF THE INVENTION
The object of the present invention corresponds to an antimicrobial
packaging based on the use of natural extracts and also to the process followed
to obtain this packaging. The packaging corresponding to the object of the invention
is characterised in that of its antimicrobial, antifungal and also antioxidant properties.
To achieve the specified objectives, a vehicle is used,
herein referred to as the active liquid, which is applied to a support made of plastic
materials, paper, cardboard, aluminium etc., of a rigid or flexible format.
The present invention is characterised in that the active
liquid can be applied to different packaging in the form of different types of coatings
or as a spray.
The active liquid is comprised of resins, which are selected
depending on the type of packaging, solvents that give the system fluidity, additives
that confer it flexibility and, finally, of active components, which in this case
are natural extracts with or without fixatives.
Therefore, the present invention can be included within
the area of varnishes used to coat packaging used for the storage and conservation
of products, mainly but not exclusively, to store food products, in order to improve
the characteristics of the packaging and the packaged product.
BACKGROUND OF THE INVENTION
To date, active packaging is one of the most important
technological innovations to preserve food products. This packaging is designed
in order to provide the packed product with an additional protection, using the
interaction between the food or product contained in the packaging to improve its
preservation and acceptability.
The actions carried out to improve the quality of the products
inside the packaging include:
- the addition of some compounds into the package, such as oxygen scavengers,
moisture absorbers, ethylene absorbers and others.
- The addition of new components, dissolved or incorporated into the packaging
material, such as antioxidants or others.
These solutions, already known as protective measures and
as means to improve the packaged products, present some drawbacks, such as involving
the incorporation of foreign bodies inside the package, alteration of the organoleptic
properties of the products by introducing foreign elements or irregular distribution
of the protective properties.
This can even lead to a complete loss of the intended activity
(loss of efficacy) when there is no direct contact between the product to be protected
and the packaging, since protection is achieved by direct contact.
It is also a clear drawback to have to make a film in each
case with the additional requirement of having to store films of different composition.
Until now, only one type of packaging which includes an
antioxidant formulation has been described, also by the authors of this patent.
The object of the invention can not under any circumstances be considered a later
version of the same patent, since the objective of the first patent was only to
prevent oxidation occurring in the packaging, without any antimicrobial or antifungal
activity, and used different products to achieve this.
There are no known cases of packaging with antimicrobial
and/or antifungal activity where the liquid used for these purposes is incorporated
into the manufactured packaging, since in other solutions proposed for similar purposes
the elements used to achieve these objectives require this to be incorporated in
the formats during the polymerisation process and while obtaining the plastic material.
On the other hand, some processes achieve the same objectives
but use chemical compounds obtained synthetically. This is a drawback from the consumer's
perspective since these products must first be approved and present potential unknown
risks for human health.
To achieve these properties, natural extracts or essential
oils are used that form part of an active liquid which is applied as a coating to
the packaging. In this way, active agents are immobilised on the packaging material
and the system as a whole presents the antimicrobial or antifungal properties. To
achieve this antimicrobial and antifungal action, direct contact with the food product
to be protected is not required since the protection is given by controlled release
of the antimicrobial agents in the active liquid used to manufacture the packaging.
The use of natural extracts has the advantage that all
of these are classified as GRAS material (Generally Recognized as Safe) and are
derived from plants used as condiments in food products.
Hence, another objective of the invention is to overcome
previous drawbacks of:
DESCRIPTION OF THE INVENTION
- incorporating antimicrobial products during the manufacturing process of the
packaging, with the incorporation of these to the final manufactured packaging format.
- the need for direct contact between the food products to be protected and the
packaging with the protection formulation, since a vapour phase is produced responsible
for protection of the food products.
- using chemical products of unique formulation obtained synthetically and with
unknown health risks.
The antimicrobial packaging which corresponds to the object
of the invention, basically consists in packaging of any material, format and arrangement,
to which an active liquid has been applied which, among other elements, contains
essential oils with an antimicrobial, antifungal and presumably also an antioxidant
The active liquid can be applied to the final format of
the manufactured packaging before it is filled with the desired product, therefore
it is not necessary to have a large store or active packaging of different characteristics
for the different products to be packaged.
The active liquid is comprised of:
- a formulation made up of:
- o a resin base such as nitrocellulose, acrylic, vinylic or others, chosen depending
on the type of packaging to which the liquid is applied, to achieve good adhesion.
- o Solvents which give the active liquid fluidity.
- o Additives to give flexibility or other characteristics to the coating.
- o Natural extracts based on essential oils that contain the active agents together
with appropriate fixatives, which produce blocking or immobilization effects of
the agents required for the desired antimicrobial and antifungal characteristics
and permit controlled release of the active agents.
The natural extracts used, among others, can correspond
to cinnamon, clove, ginger, rosemary, oregano, dill, basil etc. or other similar
compounds derived from plants, either alone, or combined in appropriate proportions
depending on the desired effect. The proportion of extracts ranges from 0.1 % to
10% in weight of the active liquid.
The natural extracts added to the base formulation can
be in the form of an essence alone or combined with a fixative which retains the
volatile elements of the natural extracts and which play the most active role in
inhibiting growth of bacteria, yeasts and fungi.
The desired objective is complete inhibition of growth
of bacteria, yeasts and fungi, producing their total elimination and preventing
Depending on the type and the concentration of the extract
used and whether or not it is used as a fixative, complete inhibition or at least
a reduction in colony forming units (CFU) is achieved for some types of bacteria,
fungi or yeasts.
Since certain food types favour the growth of certain bacteria
and/or fungi, different types or combinations of natural extracts are required in
each case, in order to achieve complete inhibition of all the possible bacteria,
fungi and yeasts that can arise.
In some cases, the combination of natural extracts has
been found to have a synergic effect on its inhibition properties, significantly
improving the active efficiency.
The following tables are included in an attempt to demonstrate
the effect of natural extracts added to a basic formulation applied to packaging,
where the following abbreviations are used:
• BACTERIA DIFFUSION ASSAYS (TABLE 1)
- CFUs per ml = colony forming units per ml
- Control = the standard microorganism culture produced in the Petri dish used
in laboratory experiments.
- P0 = the basic formulation without any extract.
- PCA1 = the basic formulation to which cinnamon essence is added at 1% in weight
of the active liquid.
- PCA4 = the basic formulation to which cinnamon essence is added at 4% in weight
of the active liquid.
- PPeCA1 = the basic formulation to which cinnamon essence is added at 1 % together
with a fixative.
- PPeCA4 = the basic formulation to which cinnamon essence is added at 4% together
with a fixative.
• FUNGI DIFFUSION ASSAYS (TABLE 2)
3.2E + 4
3.4E + 4
1.0E + 3
1.4E + 4
6.1 E+ 3
As can be observed in table 1, the number of colony forming
units (CFUs/ml) of bacteria is zero, i.e. there are NO colony forming units for
most of the bacteria and for any of the fungi and yeasts for a 4% extract of cinnamon
essence with fixative.
Also, in table 2 we can observe that colonies of fungi
are not formed with 1% extracts of cinnamon combined with fixative.
Logically, these experiments have been carried out with
natural extracts such as cloves, basil, rosemary etc. producing in some cases a
decline in the number of colony forming units (CFUs) and a radius of inhibition
inside which no colony develops, while in other cases there is total inhibition,
i.e. there is no growth of a specific bacteria, yeast or fungus.
The process to obtain the antimicrobial packaging has the
- Preparation of a basic formulation comprised of a resin substrate, some solvents
and some additives to confer the final characteristics to the coating.
- Dispersion and dissolution of natural extracts in the basic formulation that
contain antimicrobial and fungicidal active agents. The solution or dispersion is
made using Cowles type rotor stator assemblies, wet mills or other similar devices.
- Incorporation of the active liquid to the chosen package or support.
- Drying of the packaging, either in the open air or with forced air.
Incorporation of the active liquid to the package can be
- by impregnating the support in the active liquid
- by coating the different forms of the support
- by spraying the active liquid on the support
The packaging to which the liquid is applied can be made
of plastic, paper, cardboard, tinfoil, steel, aluminium or glass, either of one
material or in several layers. Materials used can be virgin or recycled.
The supports to which the active liquid can be applied
- Polypropylene and all its forms
- Polyethylene and all its forms
- Polyester (PET, PETG)
- Polystyrene and all its forms
- Cellulotic films (cellophane) and all its forms
- Paper and all its forms
And all the complexes that can be formed from these materials
(by adhesion, lamination or extrusion).
DESCRIPTION OF THE DRAWINGS
As a complement to the present descriptive report and to
make it easier to understand, this is accompanied by a set of plans. The most significant
aspects of the invention are represented in the figures of these plans, these must
be considered as illustrative and in no way limit the scope of the invention.
Figure 1. This shows a schematic representation of the
steps of the manufacturing process of the antimicrobial packaging based on the essence
of the object of the invention.
Figure 2. This shows a schematic representation of the
materials used to manufacture the active liquid applied to the final packaging.
PREFERRED EMBODIMENT OF THE INVENTION
In view of the figures, a preferable application of the
proposed invention is described.
Figure 1 represents the steps required for the process
to manufacture the antimicrobial packaging which constitutes the object of the invention
and consists of the following steps:
- Preparation (1) of a basic formulation, which is comprised of a resin substrate,
some solvents and some additives which confer the coating with its final characteristics.
- Dispersion and dissolution (2) of natural extracts that contain the active antimicrobial
and antifungal agents in the basic formulation. The dissolution or dispersion is
carried out using stirrer systems such as "Cowles" type rotor stator assembly, wet
mills or by other similar methods.
- Incorporation (3) of the active liquid to the chosen packaging or support.
- Drying (4) of the packaging, either in the open air or by forced air.
The active liquid can be incorporated to the packaging
- Impregnation (3.1) of the packaging by the active liquid in spray.
- Coating (3.2) of the different packaging formats.
- By spraying (3.3) the packaging with the active liquid.
Figure 2 shows that the active liquid (10) is comprised
- a basic formulation (5) comprised of
- o A resin substrate (6) made of nitrocellulose, acrylics, vinylic or other compounds
the selection of which is based on the type of support to which they are to be applied,
in order to achieve good adhesion.
- o Solvents (7) which confer fluidity to the active liquid.
- o Additives (8) to give flexibility or other characteristics to the coating.
- Natural extracts (9) based on essential oils that contain active agents which
produce a blocking effect or immobilisation of the active agents that confer the
desired antibacterial and fungicidal characteristics.
This description is sufficient for any expert in the area
to understand the scope of the invention and the benefits that can be derived from
The materials and size, shape and arrangement of the components
may vary provided that the essence of the invention remains the same.
The terms used in this descriptive report should always
be interpreted in their broadest sense and not in a restrictive way.