IT202100003359A1 - AQUEOUS COMPOSITION FOR ACTIVE PACKAGING CONTAINING NATURAL ANTIMICROBIAL AND/OR ANTIOXIDANT SUBSTANCES AND ACTIVE PACKAGING HAVING A COATING LAYER OBTAINED FROM SUCH AQUEOUS COMPOSITION - Google Patents

Description

DESCRIPTION

Field of application

In its most in general, the present invention refers to the technical sector of active packaging for perishable food products, such as in particular but not exclusively fruit and vegetable products.

In particular, the present invention relates to an aqueous composition comprising a particular combination of natural substances having antimicrobial and / or antioxidant that ? suitable for application on packaging for food products, such as fruit and vegetables, as well as to delay and/or slow down senescence and alteration phenomena of the products contained in the packaging. This composition? preferably in the form of an aqueous solution or dispersion of the aforesaid active ingredients, for example a colloidal dispersion.

The present invention also relates to a process for preparing a composition as above and an active packaging or an active component or accessory thereof, comprising a coating layer on one of its surfaces obtained from a composition of the aforementioned type.

The present invention also relates a process for the production of active packaging or an active component or accessory thereof which provides for the application of a composition of the aforementioned type on a surface of packaging or a component or accessory thereof to form a coating layer on it containing said active natural substances to activity? antimicrobial and/or antioxidant.

Known art

As ? known, in the food packaging sector, in particular perishable food products such as fruit and vegetables, ? of great use? being able to slow down the degradation phenomena typical of these products in order to increase their so-called shelf-life and offer the product at the best possible quality level in organoleptic terms. There? ? even more important where these products have to travel long distances, for example to be exported and/or where the distribution time of the same ? relatively long before the products can be purchased and consumed.

For this purpose, a solution adopted in this sector? that of packaging perishable food products such as fruit and vegetables in so-called ?active? packages, i.e. packages which, in addition to offering passive protection to the packaged food product by the packaging materials, are also equipped with systems capable of controlling the concentration of volatile substances or gases related to degrading processes in the head space of the package or directly in contact with the packaged product through the release of active useful substances or through the sequestration of unwanted substances.

For example, active packages containing oxygen, moisture, carbon dioxide or ethylene absorbers, active packages containing ethanol or carbon dioxide emitters, as well as active packages capable of releasing active substances with active activity are known. antimicrobial or antioxidant.

These substances can be contained in sachets to be inserted directly into the package or they can be incorporated in a polymeric matrix forming a coating film of the package or in the polymeric matrix of the packaging material.

Are they otherwise known? polymeric compositions comprising a polymeric matrix in which an intercalation composite is dispersed comprising an inorganic component with a lamellar structure such as hydrotalcite of the Mg-Al or Zn-Al type and an active substance with antibacterial or antioxidant, such as for example citric acid or chitosan, intercalated in the lamellar structure of the inorganic component. Such compositions can be used to form a coating layer of an active package and allow to obtain an adequate release of the active substance in the package for a shorter time. prolonged. Polymer compositions of this type and their use in active packages are described, for example, in EP 2310318, EP 1985585, WO 2010/128204 and WO 2013/060738.

While the above polymeric compositions containing active substances are suitable for use in active packaging, they are suitable for use in active packaging. The need is felt in the sector to devise compositions for use in active packaging which allow further improvement of the conservation characteristics of packaged perishable food products, preserving their organoleptic characteristics as much as possible. as long as possible.

The main purpose of the present invention ? therefore that of making available a composition for application in the creation of an active packaging such as a package which satisfies the aforesaid requirement.

Another object of the present invention ? that of providing an active packaging and/or an active packaging component or accessory having a coating layer formed starting from a composition of the aforementioned type.

Further purpose of the present invention? that of making available a process for manufacturing an active packaging and/or an active packaging component or accessory as above which is simple and economical to manufacture.

Summary of the Invention

Has the Applicant found that active packaging offers better shelf life characteristics? of perishable food products, in particular fruit and vegetables, packaged inside where an internal surface of the packaging or the surface of one of its accessories applied to it is coated with at least one coating layer obtained from a composition containing a particular combination of active substances of natural origin able to offer an activity? antimicrobial and a? activity? broad spectrum antioxidant.

On the basis of the above, the aforementioned aims are primarily achieved, according to the invention, by an aqueous composition suitable for making an active packaging comprising, as active components, 1-10%, preferably 1-6% chitosan, 1 -10%, preferably 1-5% of citric acid and/or a salt thereof (citrate), 0.1-5%, preferably 0.4-3% of polyphenols of which a part are tannins and 0.001-0.1 %, preferably 0.002-0.075% of flavonoids, where the percentages are by weight on the total weight of the aqueous composition.

In one embodiment, the aqueous composition according to the invention is in the form of an aqueous solution or dispersion, in particular a colloidal dispersion.

In one embodiment, the aqueous composition according to the invention does not contain (that is, is devoid of) polymeric matrices from fossil sources of dispersion of the above active components.

In one embodiment, at least one of the above active components, in particular chitosan and/or citric acid and/or citrate? present in the composition at least in part as an intercalation composite comprising an inorganic component with lamellar structure with neutralized net positive or negative charge capable of intercalating an active ingredient in said lamellar structure and at least one of the aforementioned active components intercalated at least partially in said lamellar structure .

In one embodiment, the aqueous composition according to the invention comprises one or more? of additional active components selected from the group consisting of natural essential oils, ascorbic acid, salicylic acid and benzoic acid.

The aforementioned objects are also achieved by a process for the production of an aqueous composition for active packaging as above, the process comprising the steps of mixing in water, chitosan, citric acid and/or a salt thereof (citrate), a source of of polyphenols, part of which are tannins, a citrus extract containing flavonoids and, optionally, one or more of the further aforesaid active components until an aqueous solution or dispersion containing said active components is obtained.

Are the aforementioned purposes also achieved? from an active packaging or an active component or accessory thereof comprising at least one coating layer on at least one of its surfaces obtained from an aqueous composition of the aforementioned type.

Are the aforementioned purposes also achieved? from a method for making an active packaging as above.

In one embodiment, this method comprising the steps of:

1) to make available an aqueous composition containing active components of the above type,

2) applying such a composition to at least one surface of a packing sheet,

3) dry this composition cos? to form a coating layer containing said active components on said at least one surface of the packaging foil, resulting in an active packaging foil,

4) optionally repeating the aforementioned steps 2) and 3) so as to form at least one further coating layer containing said active components on said at least one surface of the foil for packaging;

5) forming said active sheet so as to obtain an active packaging in which said surface coated with one or more? coating layers containing said active components constitutes an inner surface of said packaging.

In another embodiment, the above process comprises the steps of:

1) making available an aqueous composition containing active components of the aforementioned type and a preformed packaging for food products;

2) applying said aqueous composition on at least one internal surface of said preformed packaging,

3) to dry said aqueous composition so? to form a coating layer containing said active components on said at least one internal surface of the packaging, obtaining an active packaging,

4) possibly repeating the aforementioned steps 2) and 3) so as to form at least one further coating layer containing said active components on said at least one internal surface of the package.

Are the aforementioned purposes also achieved? from a process for the production of an accessory or component for active packaging comprising the phases of:

1) to make available an aqueous composition containing active components of the above type,

2) applying this aqueous composition to at least one surface of a packaging accessory or component,

3) to dry said aqueous composition so? to form a coating layer containing said active components on said at least one surface of the accessory or packaging component,

4) possibly repeating the aforementioned steps 2) and 3) so as to form at least one further coating layer containing said active components on said at least one surface of the packaging accessory or component.

Further characteristics and the advantages of the present invention will become more evident from the following description of some preferred embodiments, said description being provided by way of non-limiting example.

Detailed description

In the present invention, the packaging can be any package or any container having characteristics suitable for containing a food product, in particular a perishable food product, such as a fruit and vegetable product. The packaging can be of a rigid or flexible type and have any desired shape. For example, the packaging can? be a rigid container of any shape on which ? subsequently applied or welded a lid or sealing film to form the final package, an envelope, a container such as a tray, a tub or a basket, a container with a honeycomb structure, etc.

Also falling within the scope of the present invention are components of a food packaging and accessories applied to a food packaging, for example inserts such as diapers (pads) made of liquid absorbent material (for example cellulose) or paper material, bubble film ?air (bubble wrap) for impact protection, labels etc.

The packing material can be any material suitable for packaging food products such as a plastic material, a paper material, wood and combinations thereof.

The plastic material can preferably be selected from polystyrene (PS), polypropylene (PP), polyethylene terephthalate (PET) and combinations thereof.

Furthermore, the plastic material, for example PET, for use in the present invention comprises a virgin plastic material, for example virgin PET (i.e. newly produced directly from a fossil source), a recycled plastic material, for example recycled PET (r-PET) from post-consumer, a recyclable plastic material such as recyclable PET, in particular from thermoforming waste and combinations thereof.

Alternatively, the plastic material can be a biodegradable plastic material. With the term ?biodegradable? means any polymeric material having characteristics suitable for use in the production of packaging containers and which, after its life of use, can be degraded by microorganisms (bacteria and/or fungi) for example in water, natural gases, such as carbon dioxide and methane, and/or in biomass. Biodegradable polymer material can? also be compostable, that is to say that it? a biodegradable material which in an industrial composting process (55-60?C) disintegrates by at least 90% in 3 months (EN 13432) breaking down within six months into CO2, water and minerals, without releasing toxic substances into the compost.

The biodegradable and possibly compostable polymeric material can? be preferably selected from polylactic acid (PLA); mixtures of biopolymers mixed or combined in multiple layers based on starch, compostable biodegradable polyesters and mineral fillers belonging to the family of biopolymers known under the trade name Mater-bi? (Novamont?); polybutyrate (PBAT) Ecovio? Ecoflex? (BASF?); polybutylene succinate (PBS) and poly hydroxy alkanoates (PHB, PHBV), caprolactone, etc.

The aforementioned biopolymeric materials can be mixed or combined with each other in multiple layers to obtain structures having functional mechanical and permeability? to gases different when compared to the structures obtained from individual biopolymers. Also, the biodegradable material, for example PLA, can? be virgin (i.e. newly produced), recyclable, for example from thermoforming waste, or a combination thereof.

Paper material can preferably be chosen from paper, cardboard and the like.

Is the composition according to the invention suitable for making an active packaging? in the form of an aqueous solution or dispersion comprising 1-10%, preferably 1-6% chitosan, 110%, preferably 1-5% citric acid and/or a salt thereof (citrate), 0.1-5%, preferably 0.4-3% of polyphenols of which a part are tannins and 0.001-0.1%, preferably 0.002-0.075% of flavonoids, where the percentages are by weight on the total weight of the aqueous composition.

In the present invention, with the term ?antimicrobial? means a substance capable of inhibiting the growth of bacteria, molds and/or fungi (antifungal).

Furthermore, the term ?antioxidant? means a substance capable of reducing the deterioration of foods caused by their contact with the oxygen in the air.

The chitosan ? a natural polysaccharide composed of D-glucosamine and N-acetyl-D-glucosamine linked by ?(1-4) bonds. It ? obtained from the exoskeleton (the external skeleton) of crustaceans and has an activity? antimicrobial. In the present invention, with the term ?chitosan? it is also intended to include salts and derivatives thereof such as for example chitosan hydrochloride.

Citric acid and its salts (citrates) have an activity antioxidant. Suitable salts of citric acid for food use can be, for example, sodium citrate and potassium citrate.

The polyphenols contained in the composition according to the invention are soluble in water and have activity? antimicrobial and, among other things, activity? antioxidant. They may contain hydrolysable tannins and/or condensed tannins or flavanols which are also referred to as proanthocyanidins. Hydrolysable tannins hydrolyze when heated in the presence of strong acids to form glucose and ellagic acid or gallic acid. Therefore, they are divided into gallotannins and ellagiotannins.

In the composition according to the invention the polyphenols, part of which are tannins, can come from suitable sources of natural origin as extracts in liquid form (for example aqueous solution) or dried form (solid, powder, paste, gel or pellet). In particular, the extracts containing a mixture of polyphenols, part of which are tannins, can be obtained from appropriate plant sources, for example from the processing of oak bark or other plant essences and with methods per se? conventional.

In the composition according to the invention, the flavonoids can also come from sources of natural origin. Preferably, they are introduced into the composition by a citrus extract and as such are also referred to as bioflavonoids. Citrus extract refers to a composition obtained from the extraction of water-soluble compounds from the fruits of plants belonging to the Citrus genus. Citrus extract can include extracts from the fruits of one or more? citrus species such as Citrus aurantium amara (commonly known as bitter orange, sour orange, Seville orange or marmalade orange), Citrus reticulate (commonly known as tangerine) and Citrus sinensis (commonly known as sweet orange or navel orange). Can also be used extracts of other citrus fruits, depending, for example, on the availability? seasonality, cost and concentration of active antimicrobial ingredients present in these fruits.

The citrus extracts useful in the composition according to the invention are preferably aqueous citrus extracts, in particular citrus extracts with water and glycerin. Do they own businesses? antimicrobial due in particular to the presence of polyphenols and/or bioflavonoids in a relatively high concentration, i.e. a bioflavonoid concentration between 0.2% and 1.5% and/or a polyphenol concentration between 1.5% and 6% by weight on the total wet weight of the citrus extract.

The aforementioned citrus extracts may contain additives such as citric acid, lactic acid and/or ascorbic acid, for example in quality? of stabilizers.

The above citrus extracts can be in liquid form resulting from the extraction process or they can be dried to form liquid, solid, gel, powder or other forms concentrates.

The above active components can be present in the composition according to the invention in free form or some of them, in particular chitosan, citric acid and/or citrate, can be present at least partially as an intercalation composite in which they are in a form intercalated in a component (solid) inorganic lamellar structure with net positive or negative charge neutralized with properties? of intercalation of active ingredients.

With ?lamellar structure inorganic component? means an inorganic compound which, due to its chemical structure, forms a solid which is arranged spatially as a succession of lamellae, ie? of crystals that have a much smaller dimension than the other two. If the lamellas carry an electric charge (positive or negative), ions of opposite charge are positioned inside the galleries between the lamellas, to preserve neutrality. electricity of the solid. These ions can be replaced by active molecules in ionic form, through ion exchange reactions obtaining an intercalation composite in which these molecules are inserted (intercalated) in the inter-lamellar region of the inorganic component with a lamellar structure.

In one embodiment, the lamellar-structured inorganic component having properties of intercalation ? selected from Mg-Al type hydrotalcite, Zn-Al type hydrotalcite and zirconium phosphate (Zr-P).

Preferably, the inorganic component with a lamellar structure endowed with properties of intercalation ? zirconium phosphate (Zr-P).

In one embodiment, the aqueous composition according to the invention comprises free chitosan and chitosan intercalated in an intercalation composite, where the amount? of intercalated chitosan ? preferably between 0.5 and 1.5% by weight on the weight of the composition.

The use of intercalation composites allows a slow release of the intercalated active substances thus allowing? an antimicrobial and/or antioxidant action for a prolonged time to the advantage of a longer shelf life of perishable food products packaged in packaging on which it? applied the composition according to the invention.

In a preferred embodiment, the aqueous composition according to the invention comprises 0.85-4.5% of free chitosan, 1-5%, of citric acid, 0.4-3%, of polyphenols a part of which are tannins, 0.002-0.075% flavonoids and 0.5-1.1% chitosan intercalated in an intercalation composite whose inorganic component with a lamellar structure ? zirconium phosphate (Zr-P).

The composition according to the invention can include additional active components having activity? antimicrobial and / or antioxidant cos? to further increase and/or modulate the antimicrobial and/or antioxidant action by the active components of the composition according to the invention.

These active components can be chosen from natural essential oils, ascorbic acid, salicylic acid and benzoic acid. The essential oils can be chosen from the group consisting of limonene, geranial, thymol, carvacrol.

? surprisingly it has been found that the combination of active substances contained in at least one surface coating layer of an active packaging obtained from the composition according to the invention ? able to effectively counteract the development of microflora due to spoilage of packaged food products, especially fresh fruit and vegetables, thus improving? the conservation characteristics of these packaged products, preserving their organoleptic characteristics for longer times? long. These active substances with activities antimicrobial and/or antioxidant are released by at least one layer of coating applied to the surface of the packaging in a progressive and modulated way to the packaged food product, both by direct contact and by diffusion in the head space, slowing down post-harvest alterations (such as mold softening, discolouration) caused by bacteria, molds and/or yeasts and chemical-physical alterations (oxidation, darkening).

Pi? in detail, how will it be? more evident in the examples, the active substances applied on the surface of the packaging are able to act synergistically on a wide range of bacteria, molds and yeasts, thanks to their specificity? antimicrobial, and also their modality? of action appears to be balanced between efficacy by contact and efficacy by diffusion.

In particular, in the case of packaging fresh fruit and vegetables, the active substances of the coating layer applied to the surface of the active packaging are effective both by contact and by diffusion of volatile substances on bacteria and microorganisms such as:

-Botrytis cinerea (Bc, fungus), responsible for gray mold affecting small fruits, grapes, tomatoes, strawberries, cherries, cultivated mushrooms;

-Monilia laxa (Ml, fungus), responsible for brown rot on cherries;

-Pseudomonas syringae pv. tomato (Pst, bacterium), responsible for bacterial specks on tomatoes;

-Total bacterial load (CBT, bacteria), responsible for various alterations on small fruits, grapes, tomatoes, strawberries, cherries, cultivated mushrooms.

? it should also be noted that the composition according to the invention for application to form an active packaging contains active substances of natural origin (GRAS - generally recognized as safe) and does not require an organic polymeric matrix from fossil sources for the dispersion of these substances for the aforementioned application. Therefore, the composition according to the invention has a lower environmental impact. reduced compared to compositions of the known art for the same application in which the active substances are dispersed in a polymeric matrix obtained from fossil sources or synthetic waxes and this? it also allows to improve the disposal characteristics of the packaging on which the composition? applied and/or to increase the rate of recyclability? of such packaging. At the same time, thanks to the use of a combination of natural active substances as indicated above, ? It is possible to avoid the use of synthetic antimicrobial substances in the composition according to the invention while still obtaining an effective action against the microorganisms responsible for spoiling perishable food products substantially equal to or even higher than that exerted by synthetic antimicrobial substances.

The composition according to the invention, when used to make an active packaging, is also advantageous due to the substantial absence of odors or flavors transmitted to the food product packaged in this packaging.

The active composition according to the invention can be prepared by mixing in water chitosan, citric acid and/or citrate, a mixture of polyphenols, part of which are tannins, a citrus extract containing flavonoids and, optionally, further active components as indicated above, as well as to obtain an aqueous solution or dispersion containing the above components, in particular a colloidal aqueous dispersion.

Chitosan is added to the mixture of the aforementioned components in an amount between 1% and 10%, preferably between 1% and 6% on the total weight of the aqueous solution or dispersion. In one embodiment, a part of the chitosan, preferably from 0.5 to 1.5% by weight, is added in the form of chitosan intercalated in an intercalation composite whose lamellar-structured inorganic component has properties of intercalation ? selected from Mg-Al type hydrotalcite, Zn-Al type hydrotalcite and zirconium phosphate (Zr-P), preferably zirconium phosphate (Zr-P).

L? Citric acid and / or citrate is / are added / the in a quantity? between 1% and 10% by weight on the total weight of the aqueous solution or dispersion, in particular between 1% and 5%.

The source of polyphenol mixture, part of which are tannins can? be a liquid extract containing between 40% and 60% of polyphenols expressed as tannins according to the method of the ISO14088:2020 standard where the percentages are by weight on the weight of the liquid extract.

Preferably, the aforementioned liquid extract containing the mixture of polyphenols, part of which are tannins, is added in an amount between 0.25% and 8.3%, preferably between 1% and 5% by weight on the total weight of the aqueous solution or dispersion.

The citrus extract? preferably a liquid citrus extract containing a complex of organic acids (1.5 to 4% ascorbic acid, 0.3 to 2% citric acid, 0.3 to 2% lactic acid), bioflavonoids (0.2 to 1.5%), polyphenols (from 1.5 to 6%) stabilizers and glycerin.

The citrus extract is added in a quantity between 0.5% and 6.6%, preferably between 1% and 5% by weight on the total weight of the aqueous solution or dispersion.

In one embodiment, the process for preparing the composition according to the invention comprises the steps of:

- add chitosan and citric acid and/or citrate to the water, obtaining a dispersion;

- keeping this dispersion under stirring at a temperature between 15°C and 80°C for a time sufficient to dissolve the chitosan substantially completely, obtaining a solution; preferably the maintenance time of the aforementioned dispersion under stirring? between 2 and 4 hours at 30°C, in particular 3 hours.

- adding the liquid extract of the mixture of polyphenols, part of which are tannins, the liquid extract of citrus fruits and, optionally, further active components to said solution, obtaining an aqueous dispersion, preferably a colloidal aqueous dispersion.

The composition according to the invention can be used directly for the creation of an active packaging or pu? be applied on a component used to form the? active packaging or still pu? be applied to an accessory applied to the packaging.

In one embodiment, the composition according to the invention can be applied in a quantity? prefixed on at least one surface of a sheet of a packing material followed by drying of such composition so? to form a coating layer (film) on that surface.

The material forming the leaf can? be, for example, a plastic or paper material chosen from those indicated above.

The application of the composition can? be carried out by means of techniques per s? such as spraying, roll coating, dip coating, casting, blade application, etc.

L? Drying of the composition can? be carried out by means of techniques per s? conventional techniques, for example by means of hot air, drying in an oven at a temperature preferably comprised between 60°C and 70°C or other conventional techniques so to obtain a coating layer adequately adhered to the application surface and containing the active components.

If desired or appropriate, before applying the composition according to the invention, the sheet of packaging material can be be subjected to a treatment on the application surface to improve its adhesion characteristics with the composition subsequently applied thereon. Such surface treatment ? by itself conventional and can be carried out in various ways, for example by corona treatment, plasma treatment or laser treatment.

Such surface treatment ? optional but, in the case of plastic packaging, it can? be preferable to remove a layer of non-stick material (eg silicone) that can? be applied on the surface of the polymeric sheet during its production in order to favor its sliding, in particular during the winding to form a reel and the unwinding from the reel, thus avoiding that the presence of this non-stick material could compromise the adhesion of the composition according to the invention on the application surface of the sheet.

The above operations of application of the composition according to the invention on the surface of the leaf and subsequent drying can be repeated cyclically as follows: to form one or more? additional layers of coating on that surface.

The quantity? of the composition applied to the surface of the leaf for each coating layer pu? vary within wide limits depending, for example, on the geometry of the packaging used, on the modality? of application of the composition, of the packaged food product and / or other factors so? to ensure an adequate degree and duration of activity? desired antimicrobial and/or antioxidant in active packaging.

In one embodiment, the aqueous composition according to the invention can be applied for each application phase in a quantity? between 5 g/m<2 > and 30 g/m<2>, preferably between 10 g/m<2 > and 20 g/m<2>, even more? preferably between 15 g/m<2> and 20 g/m<2>, for example 17-20 g/m<2>.

In one embodiment, the composition according to the invention is applied in an amount adequate so as to distribute on the surface of at least one layer of surface coating on the active packaging or its component or accessory, and obtain, after drying, a quantity of active substances preferably between 0.44 mg/dm<2 > and 13 mg/dm<2 > of free chitosan, between 0.5 mg/dm<2 > and 15 mg/dm<2 > of free citric acid, between 0.6 mg/dm<2 > and 9 mg/dm<2 > of tannins from the polyphenol extract and between 0.001 mg/dm<2 > and 0.226 mg/dm<2 > of flavonoids from the citrus fruit extract, and between 0.78 mg/dm<2 > and 3.12 mg/dm<2 > of chitosan intercalated on an intercalation composite, preferably based on Zirconium phosphate.

Subsequently, the packing material sheet treated with the composition according to the invention can be formed so as to obtain the final active packaging in which the surface coated with at least one coating layer obtained from the above composition constitutes an internal surface of the packaging.

The forming can be carried out by procedures per s? conventional. For example, in the case of a sheet in thermoplastic material, this sheet can be thermoformed according to conventional techniques cos? to obtain a container (for example a tray or a tub) in which the surface covered with at least one coating layer formed by the above composition constitutes an internal surface of the container, for example the bottom and/or side walls of the container.

To this container, after placing the food product to be packaged in it, can be associated or welded a lid or closure, also by means of a film film, thus obtaining the final active package.

Alternatively, the plastic or paper material leaf (or film) can be folded to form a container or envelope wherein the surface coated with at least one coating layer formed by the above composition constitutes an inner surface of the container or envelope.

To this container, after placing the food product to be packaged in it, can be associated or welded a lid or closure also by means of a film film thus obtaining the final active package. In the case of the bag, after inserting the food product to be packaged, the same can be closed with suitable closure means or welded at its mouth, thus obtaining the final active package.

In another embodiment, the composition according to the invention can be applied in a quantity? fixed on at least one surface of a packaging already? preconstituted (preformed) according to the modalities? indicated above, what? to form at least one coating layer containing active components on an inner surface of the package.

For example, the? pre-made packaging can? be a previously formed plastic, paper or wooden container, and the composition according to the invention can be applied in the manner? indicated above on the bottom and / or on the side walls of the container so? to form at least one coating layer containing active components on the bottom and/or sidewalls of the container.

In yet another embodiment, the composition according to the invention can be applied in a quantity? fixed on at least one surface of a component or a packaging accessory according to the modalities? indicated above, what? to form at least one coating layer containing active components on a surface of that component or packaging accessory.

The packaging component can be for example a lid or foil as a sealing film.

The packaging accessory can be any complementary functional accessory applied to the packaging, for example inserts such as diapers (pads) of liquid absorbent material (for example cellulose) or in paper material and bubble wrap (pluriball) for protection against shocks or a label.

This invention will come now illustrated with reference to the following examples provided for indicative and non-limiting purposes.

Example 1 ? Preparation of compositions according to the invention

A composition according to the invention (hereinafter composition A) is? been prepared as follows.

1.2 g of chitosan hydrochloride (CAS 70694-72-3) and 1.2 g of anhydrous citric acid powder (CAS 77-92-9) were added in 100 ml of deionized water, obtaining a dispersion. The dispersion? was kept under stirring by means of a mixer for 3 hours at a temperature of 25°C (or 1 hour at 70°C) until obtaining a clear solution and the complete dissolution of the chitosan.

Subsequently, 1 g of a liquid extract of polyphenols, a part of which are tannins, of food grade (FINTAN AP 50 ? ) having a polyphenol content expressed as a tannin content of 40% (according to the ISO 14088:2020 method) were incorporated; 1 g of a liquid citrus extract (Biosecur F440D-k -) having a flavonoid content of 0.2-1.5% and 1 g of a zirconium phosphate - Chitosan intercalation composite (Prolabin & Tefarm s.r.l.) having a of chitosan of 52% obtaining a dispersion that ? was kept under stirring for 1 hour until a substantially homogeneous colloidal dispersion was obtained (Composition A).

Table 1 below shows the quantity? of the active substances in the dispersion (Composition A) obtained as above in percentages by weight on the total weight of the dispersion.

Table 1

*content respectively expressed as Chitosan; ** expressed as tannin content; ***expressed as bioflavonoid content.

Another composition according to the invention (hereinafter composition B) is? been prepared as above except that the chitosan ? been added only in free form, i.e. without addition of the zirconium phosphate intercalation composite ? Chitosan The compositions A and B according to the above were tested by in vitro inhibition assays through the release of volatile compounds against B. cinerea.

Rolls of microbubble pad treated with composition A or B and an untreated microbubble pad as a reference were used for the assays. Tested microorganism: Botritis cinerea obtained from fresh culture. Tests of inhibition by contact diffusion through agar culture medium (PDA) and tests of inhibition of the diffusion of the aforementioned microorganism through volatile compounds released from composition A or B were carried out. The tests were carried out at incubation temperatures of 4 ?C, 12?C and 23?C and were replicated 3 times. The material treated with composition A or B ? been sterilized before the test by exposure to UV rays for 20min and then placed on top of the plate with agar (diffusion through agar), or, applied on the lid not in contact with the culture medium (in the case of the inhibition test by diffusion of volatile compounds ). The growth of B. cinerea ? was evaluated by measuring the diameter of the mycelium.

The results of the assays of diffusion inhibition of volatile compounds on B. cinerea carried out at 4°C and at 12°C are reported in Figures 1 and 2, respectively.

With reference to the results of the tests at 4?C in Figure 1, can one? note that both compositions A and B showed a percentage of inhibition of B. cinerea after 6 days of incubation of 19.29% and 22.98%, respectively. After 8 days of inhibition, composition A still maintains a significant percentage of inhibition of just over 15%.

With reference to the results of the tests at 12°C in Figure 2, one can note that both compositions A and B showed a percentage of inhibition of B. cinerea after 2 days of incubation of almost 30%, which is reduced to just over? what half? after 4 days of inhibition. Advantageously, composition A maintains these inhibition characteristics up to the eighth day of incubation whereas the inhibition percentage of composition B progressively decreases.

Similar results were also obtained in the inhibition tests by contact diffusion through agar culture medium (PDA) and in the tests at the inhibition temperature of 23°C.

Example 2 ? Active tray

Composition A of Example 1 ? was applied by means of a BYK blade system, in the form of a thin film equal to 20 g/m<2 > on the surface of a 250 micron or 500 micron sheet of PS or PET treated by corona effect (surface tension of > 40 mN/ m) to have a better adhesion of the composition (dispersion). So the leaf? been dried for 15-30 minutes in a stove at 60-70? C. The dry leaf? been thermoformed with a thermoforming machine at temperatures between 100-120?C obtaining active trays of dimensions 180x145x40mm in height.

In Figure 3 ? shown is an optical microscope photograph (5X magnification) of a portion of the treated surface of an active tray where the aggregates of the colloidal dispersion present in the thin coating film on the surface of the tray after thermoforming are visible.

Have the active trays prepared as above been used for packing strawberries and on them ? a micro-perforated sealing film was applied. The resulting active packs were subjected to shelf-life tests of the packaged strawberries using similar non-active packs as a reference, i.e. in which the tray is not? been subjected to any treatment with active substances n? first n? after thermoforming.

As a result of these tests, ? it has been found that active trays according to the invention containing 350g of strawberries packaged with microperforated top film had about 85% good fruit free from mold and softening after 5 days of storage at a temperature of 10°C.

Differently, the non-active reference trays containing 350g of strawberries packaged with micro-perforated top film only had about 29% good fruit free from mold and softening after 5 days of storage at a temperature of 10°C.

Example 3 ? Insert (bubble wrap) active

A composition according to the invention? was prepared according to the procedure described in Example 1 with the difference that 1.7 g of a citrus extract (Biosecur F440D-k -Biosecur Lab Inc.) having a flavonoid content of 0.2-1.5% are incorporated .

The composition ? was applied by taking a fraction of a known volume of the same and applying it by means of a spray airbrush, in the form of a thin film equal to 20 g/m<2 > on the surface of a sheet (film) with bubbles of PE. So the sheet? dried for 30 minutes in an oven at 60-70?C.

The resulting active bubble wrap sheet? been divided into sections measuring 80x140 mm and these sections were used as inserts applied to the bottom of respective trays measuring 180x145x40 cm.

Have the trays containing the active inserts as above been used for packaging strawberries and on them? a micro-perforated sealing film was applied by heat sealing. The resulting active packs were subjected to shelf-life tests of the packaged strawberries using similar non-active packs as a reference, i.e. in which n? the tray n? the insert have not been subjected to any treatment with active substances.

As a result of these tests, ? It was found that trays with active insert (bubble sheet) according to the invention containing 350g of strawberries packaged with micro-perforated top film had about 61% of good fruit free from mold and softening after 5 days of storage at a temperature of 10?C.

Differently, the non-active reference trays containing 350g of strawberries packaged with micro-perforated top film only had around 34% of good fruit while the rest of the fruit was heavily mouldy.

Example 4 ? Active package comprising a tray and a respective closure lid

A composition according to the invention? was prepared according to the procedure described in Example 1 with the difference that 1.7 g of a citrus extract (Biosecur F440D-k -) having a flavonoid content of 0.2-1.5% are incorporated.

The composition ? was applied by taking a fraction of a known volume thereof and applying it by means of a spray airbrush, in the form of a thin film equal to 17 g/m<2 > on packages each comprising a tray and a closing lid. Precisely, the composition? been applied to the surface of the bottom of the tray and to the inner surface of the closure lid of these packages. Then, the packages were dried for 30 minutes in an oven at 60-70°C.

The resulting active packages were used for the packaging of strawberries and were subjected to shelf-life tests of the packaged strawberries using similar non-active packages as a reference, i.e. in which n? the tray n? the respective sealing lid have not been subjected to any treatment with active substances.

As a result of these tests, ? it has been found that active packages as above according to the invention containing 350g of packaged strawberries had about 58% of good fruit free from mold and softening after 8 days of conservation at a temperature of 10°C.

In contrast, the reference non-active packages containing 350g of packaged strawberries had only about 40% good fruit while the rest of the fruit was heavily mouldy.

Example 5 ? Active container with alveolus

A composition according to the invention? was prepared according to the procedure described in Example 1 with the difference that 1.7 g of a citrus extract (Biosecur F440D-k -) having a flavonoid content of 0.2-1.5% are incorporated.

The composition ? been applied by taking a fraction of known volume of the same and applying it by means of a spray airbrush, in the form of a thin film equal to 20 g/m<2 > on met? of the surface of a cavity (60x40 cm) of a food container. So, the alveolus of the container ? dried for 30 minutes in an oven at 60-70?C.

The resulting active container ? was used for packaging peaches which were placed in the socket so that some of them were in direct contact with the surface portion of the socket coated with the thin film containing active substances while the remaining peaches were in contact with the remaining portion of the uncoated socket surface.

The container containing the packaged peaches? was then subjected to storage tests (shelf-life) of the packaged peaches.

As a result of this test, ? been found that in the half? of the alveolus of the container coated with the thin film containing active substances do not you? observed no mold growth on fruits from day 7 to day 19 of storage at a temperature of 12°C.

Differently, in the half of the alveolus of the unlined container, a fraction of the fruit showed progressive molding until 100% of the fruit was moldy on day 19 of storage.

As in the previous examples, the presence of the active substances according to the invention prevented the development of molds in the fruits present in the part of the socket treated with the composition according to the invention.

Claims (15)

1. Aqueous composition for active packaging comprising, as active components with activity? antimicrobial and/or antioxidant, 1-10%, preferably 1-6%, chitosan, 1-10%, preferably 1-5%, citric acid and/or a salt thereof (citrate), 0.1-5% , preferably 0.4-3%, of polyphenols a part of which are tannins and 0.001-0.1%, preferably 0.002-0.075%, of flavonoids, where the percentages are by weight on the total weight of the aqueous composition. 2. Composition according to claim 1, wherein at least one of chitosan, citric acid and/or citrate? present in the composition at least in part as an intercalation composite comprising an inorganic component with lamellar structure with neutralized net positive or negative charge capable of intercalating an active ingredient in said lamellar structure and at least one of said chitosan, citric acid and/or at least intercalated citrate partly in said lamellar structure. 3. Composition according to claim 1 or 2, wherein said inorganic component having a lamellar structure? selected from Mg-Al type hydrotalcite, Zn-Al type hydrotalcite and zirconium phosphate (Zr-P), preferably being zirconium phosphate. 4. Composition according to claim 2 or 3 comprising 0.85-4.5% of free chitosan, 1-5%, of citric acid, 0.4-3%, of polyphenols of which a part are tannins, 0.002-0.075 % of flavonoids and 0.5-1.1% of chitosan intercalated in an intercalation composite whose inorganic component with lamellar structure ? zirconium phosphate (Zr-P). 5. Composition according to any one of the preceding claims, comprising one or more? additional active components selected from the group consisting of ascorbic acid, salicylic acid, benzoic acid and natural essential oils selected from the group consisting of limonene, geranial, thymol and carvacrol. 6. Composition according to any one of the preceding claims, wherein the composition is free of any polymeric matrix from fossil sources of dispersion of the aforementioned active components. The process for preparing an aqueous composition for active packaging according to any one of the preceding claims, the process comprising the steps of mixing in water, 1 to 10%, preferably 1% to 6% chitosan, of which preferably from 0.5% to 1.5% by weight as chitosan intercalated in an intercalation composite, 1 to 10%, preferably 1% to 5% citric acid and/or a salt thereof (citrate), 0.25 % to 8.3%, preferably from 1% to 5% of a source containing polyphenols of which a part are tannins having a polyphenol content between 40% and 60% expressed as tannins (ISO 14088:2020), from 0.5 % to 6.6% of a citrus extract containing 0.2% to 1.5% flavonoids and optionally one or more? further active components until an aqueous solution or dispersion containing said active components is obtained. 8. Process according to claim 7 comprising the steps of: - add chitosan and citric acid and/or citrate to the water, obtaining a dispersion; - keeping this dispersion under stirring at a temperature between 15°C and 80°C for a time sufficient to dissolve the chitosan substantially completely, obtaining a solution; - adding the source of polyphenols of which a part are tannins, the citrus extract and, optionally, further active components to said solution, obtaining an aqueous dispersion, preferably a colloidal aqueous dispersion. 9. Active packaging or component or active accessory thereof comprising at least one coating layer on at least one surface thereof obtained from an aqueous composition according to any one of claims 1 to 6. 10. Active packaging or its component or active accessory in which said at least one coating layer comprises from an amount of active substances between 0.44 mg/dm<2 >and 13 mg/dm<2 >of free chitosan, between 0.5 mg/dm<2 >and 15 mg/dm<2 >of free citric acid, between 0.6 mg/dm<2 >and 9 mg/dm<2 >of tannins from the polyphenol extract and between 0.001 mg/dm<2 >and 0.226 mg/dm<2 >of flavonoids from the citrus extract, and between 0.78 mg/dm<2 > and 3.12 mg/dm<2 > of Chitosan intercalated in an intercalation composite whose inorganic component with lamellar structure? preferably zirconium phosphate (Zr-P). 11. Active packaging or component or active accessory thereof according to claim 9 or 10 wherein the packaging is? made of a plastic material, a paper material, wood or combinations thereof, in which said plastic material is selected from the group consisting of polystyrene (PS), polypropylene (PP), polyethylene terephthalate (PET) and combinations thereof, biodegradable and possibly compostable polymeric material selected from the group consisting of polylactic acid (PLA); blends of biopolymers mixed or combined in multiple layers based on starch, compostable biodegradable polyesters and mineral fillers belonging to the family of biopolymers known under the trade name Mater-bi? (Novamont?); polybutyrate (PBAT), especially Ecovio? Ecoflex? (BASF?); polybutylene succinate (PBS) and poly hydroxy alkanoates (PHB, PHBV), caprolactone, and said paper material ? chosen from paper, cardboard and the like. 12. Process for making an active packaging according to claim 9, 10 or 11 comprising the steps of: 1) providing an aqueous composition according to claims 1 to 6, 2) applying said composition to at least one surface of a packaging foil, 3) dry this composition cos? to form a coating layer containing said active components on said at least one surface of the packaging foil, resulting in an active packaging foil, 4) optionally repeating the aforementioned steps 2) and 3) so as to form at least one further coating layer containing said active components on said at least one surface of the foil for packaging; 5) forming said active sheet so as to obtain an active packaging in which said surface coated with one or more? coating layers containing said active components constitutes an inner surface of said packaging. 13. Process for making an active packaging according to claim 9, 10 or 11 comprising the steps of: 1) providing an aqueous composition according to any one of claims 1 to 6 and a preformed food packaging; 2) applying said aqueous composition to at least one inner surface of said preformed packaging, 3) to dry said aqueous composition so? to form a coating layer containing said active components on said at least one internal surface of the packaging, obtaining an active packaging, 4) possibly repeating the aforementioned steps 2) and 3) so as to form at least one further coating layer containing said active components on said at least one internal surface of the package. 14. Process for making an accessory or component for active packaging according to claim 9, 10 or 11 comprising the steps of: 1) providing an aqueous composition according to any one of claims 1 to 6, 2) applying said aqueous composition to at least one surface of a packaging accessory or component, 3) to dry said aqueous composition so? to form a coating layer containing said active components on said at least one surface of the accessory or packaging component, 4) possibly repeating the aforementioned steps 2) and 3) so as to form at least one further coating layer containing said active components on said at least one surface of the packaging accessory or component. 15. Process according to any one of the preceding claims from 11 to 14 wherein said composition is applied in an amount between 5 g/m<2 > and 30 g/m<2>, preferably between 10 g/m<2 > and 20 g/m<2>, even more? preferably between 15 g/m<2 > and 20 g/m<2>.