ES2673488B1 - PACKAGING APPLICABLE TO DEPOSIT AND CONSERVATION OF FOODSTUFFS AND USE OF A CONSERVATIVE AGENT - Google Patents

Description

DESCRIPTION

Container applicable to the storage and preservation of food products and use of a preservative agent

Sector of the technique

The present invention concerns, in a first aspect, a container applicable to the storage and preservation of food products, whose preservation properties include protection against moisture.

A second aspect of the invention concerns the use of a preservative agent, protector against moisture and suitable for food contact, for the preservation of food products deposited inside an air permeable container.

The invention is particularly applicable to the storage and preservation of bakery and pastry products, preferably pieces of bread for daily consumption to prolong the maintenance of its crispness.

State of the prior art

Various types of packaging for the storage and preservation of food products are known in the state of the art.

Such is the case, for example, of the package described in ES1024959U, which constitutes a flexible bag for the storage and preservation of pieces of bread, which includes aeration valves, or of the patent application EP0878407A1 proposing a plastic bag to contain bread or other food products, which includes a series of micro-perforations to aerate its contents.

The containers described in said patent documents meet the characteristics of the preamble of claim 1 of the present invention.

Although such containers retain to a greater or lesser extent the food products contained therein, they are not designed for very humid environments. In fact in such a class of very humid environments, due to the aeration openings included in such containers, the humidity of the environment passes into the container and affects its contents.

This is especially critical for bread pieces and the like. In this sense it should be noted that bread is the perishable product resulting from the cooking of a dough obtained by the mixture of wheat flour, edible salt and drinking water, fermented by species typical of the fermentation panaria, and that the common bread processed by traditional technique experiences loss of crunchiness (property highly valued by the consumer) particularly fast (already sensitive after two hours after baking) in high humidity environments.

This loss of crunchiness derives from the incorporation of an excess of moisture to the crust that under ordinary conditions of aeration comes from the external atmosphere that is added to that coming from the humidity of the crumb that is directed towards the outside, through the bark and that causes a decrease in the fragile behavior of the bark.

The crispness of fresh bread is the attribute most demanded by consumers; the problem is that after baking, this property is perceived for a short period of time and the loss of it causes rejection in consumers. The quality of the bread is quickly lost due to aging that begins when the pieces of bread are taken out of the oven and stored. This dynamic process is due to multiple factors and involves simultaneous mechanisms that include the loss of "flavor" (odor, taste and texture), an increase in the hardness of the crumb and loss of crunchiness of the crust. increase in water content in the same, causing the starch crystals to polymerize in amorphous regions causing a change in mechanical behavior (Aguilera JM, 2002. Topics in food technology - Vol. 1. Ibero-American Program of Science and Technology for Development (Tables, JM; Alegre, MT, 2002, Bread and its process of elaboration, Food science and technology, Vol 3, No. 5, pp. 307-313) In the stored bread, the "humidity "Of the bark is increased due to the migration of water vapor from the crumb to the bark and from the external environment towards it, giving the piece a gummy behavior.

In hostelerla, the gummy state of the bread often forces the presentation of ordinary toasted bread that is usually more appetizing for the customer, which entails spending time for the additional roasting operation.

The traditional bread boxes do not solve the problem stated regarding maintenance of crujibilidad in humid environment.

Until about 20 years ago, only one daily cooking is done, nowadays, successive firings are carried out even using the traditional technique (complete processing from mixing until the end of baking), and other techniques for the production of common bread are also used (mainly use of frozen doughs, and precooked techniques).

The traditional bread in loaves or in pieces of greater thickness of crust, maintains certain crunchiness during a relatively greater time, with respect to pieces of smaller thickness of crust. In areas characterized by frequency of high relative humidities, the bread is relatively well preserved for a certain time in freezers, but a tendency to mechanical disaggregation between crusts and crumbs is evident, and on the other hand thawing must be carried out, or let some time pass until consumption.

By their very nature, common breads of traditional process and careful elaboration experience in humid environment a degradation of physical properties that affect their acceptability by the consumer.

It is therefore necessary to offer an alternative to the state of the art that covers the gaps found therein, by providing a container that allows the preservation of food products disposed in its interior in very humid environments.

Explanation of the invention

For this purpose, the present invention concerns, in a first aspect, a container applicable to the storage and storage of food products which, in a manner known per se, comprises walls arranged so as to define an enclosure with at least one opening for the introduction of food products inside, where at least part of said walls allows air to pass through the wall in order to aerate the interior of the container.

Unlike the containers known in the state of the art applicable to the storage and preservation of food products, in the one proposed by the first aspect of the present invention, characteristically, at least one of its walls contains inside or attached on one of its faces, at least one preservative agent against moisture and suitable for food contact.

Depending on the embodiment example, the container walls of the first aspect of the invention are rigid or flexible.

According to an example of embodiment, the container of the first aspect of the present invention comprises at least one element that includes the preservative agent and which is attached to at least one side of the wall. Preferably, the package comprises a plurality of said elements attached to some faces of some or all of said walls.

As a function of the realization example, the cited or cited faces are or are one or some internal or external faces of the walls of the container that delimit said enclosure.

As regards the mentioned element, according to an example of embodiment, this is an air-permeable container that houses the preservative agent inside it.

For another embodiment, the preservative agent is integrated into the wall or walls of the container.

According to another embodiment, the preservative agent is incorporated in the composition constituting the wall or walls.

Advantageously, for an example of embodiment, the container of the first aspect of the invention comprises closing means for closing said opening once the food products are housed inside the enclosure.

Alternatively, for another embodiment, the package of the first aspect of the invention does not include closure means. Such is the case, for example, that the package is a bag of sufficient size so as not to require a cover itself, but that the walls of the bag sufficiently cover the contents of the bag by covering the opening.

For an example of embodiment, in order to allow aeration of the interior of the enclosure mentioned above, as a minimum part of the walls are made of an air permeable material allowing the passage of air through the wall.

According to different implementations of said embodiment, the walls are made of at least one air-permeable material, whether cardboard, paper, cloth or other type of material also permeable to air and suitable for food contact.

According to another example embodiment of the container of the first aspect of the present invention, at least part of the walls comprise or define holes or holes, which allow the passage of air through the wall. According to different implementations of said embodiment, the walls are made of at least one of the following materials: wicker, fabric, metal, wood or plastic, all of them including through holes, either in the form of perforations (metal, wood) or in the form of interstitial spaces between filaments (wicker, tissue).

According to the embodiment, the package of the first aspect of the invention is provided in the form of a box, bag or bag.

For an example of realization, the packaging of the invention consists of a box of cardboard or other air-permeable material that encloses a volume determined by rectangular faces of dimensions appropriate to the application for which the container is designed: fixed container for domestic use , container for commercial use, etc.

According to an implementation of said embodiment, on the faces of the box, in its internal part, the active material, ie the preservative agent, is incorporated in air-permeable bags or envelopes of pleated textile or corrugated cardboard. , whose folds or corrugations contain the active material (in the form of an arid with a granulometry suitable for the correct filling of the folds), of a thickness of approximately 6 mm.

For other examples of embodiment, the packaging of the first aspect of the invention consists of a cloth bag, woven or non-woven, air permeable, for domestic use and transport of small number of pieces, or by a paper bag, where the active material is incorporated into the composition of the paper, or by a bag of an air-permeable fabric that incorporates bags containing the active material.

Other packaging modalities will be wicker boxes, or a fabric of a certain consistency, which allow the aeration of its interior, to which the active material will be incorporated in a manner similar to that indicated for the previous embodiment.

Other modalities will be wooden or metal boxes whose aeration is achieved by an adequate number of perforations, and in whose internal faces the active material is incorporated in a manner similar to that indicated above.

Preferably, the package proposed by the first aspect of the invention is applicable to the storage and preservation of bakery and / or pastry products having crispiness properties (with at least one crunchy outer layer), and more preferably bread pieces. .

Therefore, preferably, the scope of the food products considered refers to bread and products of similar composition and texture, understood as those made from an initial mass that is molded plastically, and that is subsequently subjected to a process that reduces the content in water, and gives rise to an external sheet of lower content in humidity and greater mechanical consistency in relation to the humidity and consistency of the internal volume of the piece, difference of humidity and consistency that originates an adequate behavior of the product ( crujibilidad) that is lost more quickly in high humidity environment.

In general, the properties of protection against humidity of the preservative agent are regenerable when subjected to a temperature below 200 ° C, that is to say regenerable domestically (during the useful life of the container), since for this a domestic oven can be used , for example a microwave oven.

Advantageously, the preservative agent (and the container that houses it, when it is the case) is disposable or recyclable when the container has already degraded a lot, that is to say at the end of the useful life of the container.

The packaging of the first aspect of the invention constitutes an active and intelligent packaging, according to what is established in Regulation CE / 450/2009, which allows the transport and storage of, among other food products, pieces of bread and the like of daily consumption, maintaining them tender and crispy.

The container proposed by the first aspect of the present invention is intended primarily for the domestic consumer of food products, such as bread, but also has other applications (in general when it adopts the form of sack, box, etc ...), with the same foundation (incorporation of a suitable preservative agent), assigning it for example to distributors, transporters, hostelerla, etc.

The invention allows to prolong the conservation of bread attributes in the consumer's home during 12-24 hours in conditions of high humidity (up to 90%) which is an improvement over conventional packaging currently on the market.

A second aspect of the present invention concerns the use of a preservative agent, protector against moisture and suitable for food contact, for the preservation of food products deposited inside an air permeable container, preferably bakery products and pastry that have crispness properties.

In general, the preservative comprises at least one substance with a high sorption capacity (ab / adsorption) of moisture.

According to different embodiments, said substance with high sorption capacity is selected from at least one of the following groups, which are listed below from I to VII, and of which only those suitable for food contact are applicable:

I. Mineral substances with predominance of phyllosilicates of the groups of the classification of phyllosilicates of the AIPEA (Bailey, 1980), which are indicated below:

1 - Sepiolite group - paligorskite, like sepiolite, or paligosrskite (in North American denomination, attapulgite) or minerals of intermediate structure between these minerals.

2- Group of smectites, be these dioctaedricas (as montmorillonitas, or nontronitas) or trioctaedricas (as saponitas or hectoritas).

3- Group of vermiculites, be they dioctahedral or trioctahedral, when they occur in clay size and with a high specific surface.

4- Groups of interstratified clay minerals, whose structure presents smectite sheets.

5. Illitas and sericites, and minerals with basic structure of sheets 2: 1 assimilable to the group of micas in whose structure high contents of smectite sheets are presented.

For group 1 minerals, commercial or traditional denominations are used as batan lands, or "fullers's earths"

For the minerals of group 2, the commercial denomination of bentonites is usually used.

II. Mineral substances with a predominance of diatomite (also known as kieselguhr, or diatomaceous earth, or diatomaceous earth), with or without thermal treatment.

III. Pillared clays, synthesized by insertion by ion exchange of voluminous metal polycations in interlaminar spaces of the original clay minerals, usually from the group of smectites, greatly increasing their basal spacing, followed by calcination stabilizing the structure with a basal spacing greater than the initial .

IV. Natural or synthetic mineral substances of the group of zeolites, in general, and predominantly those classified as 4 A and 3 A (whose maximum pore sizes are less than those sizes).

V. Gels of silica and dried alumina gels.

SAW. Other non-hygroscopic moisture absorbers.

The active material can be used in different ways, either as fine powder, in granular or agglomerated form, and can be supplied as raw ore with only mechanical classification, or with physical or chemical treatments of activation.

Brief description of the drawings

The foregoing and other advantages and features will be more fully understood from the following detailed description of some realization examples with reference to the accompanying drawings, which must be taken by way of illustration and not limitation, in which:

Figure 1 is a perspective view schematically representing the package proposed by the first aspect of the present invention;

Figures 2 and 3 show the most frequent types of evolution of resistance (kg / cm2) in compression-flexion tests, at different times counted from the end of the baking of the piece of bread (1: 2 hours, 2: 5 hours, 3:10 h, and 4:24 hours), in pieces of bread preserved in conditions of extraordinary humidity (HR = 85%) using conventional containers (hollow boxes) or containers as proposed by the first aspect of the invention, that is, incorporating preservative (filled boxes).

Detailed description of some examples of realization

In Figure 1 is illustrated an embodiment for which the package 1 proposed by the first aspect of the present invention, applicable to the storage and storage of food products, is a box comprising walls 1a, 1b, 1c, 1d, 1e, 1f allowing the passage of air through it (either by being made of an air-permeable material, such as cardboard, or because they include aeration perforations) and which are arranged so as to define an enclosure with an opening A for introducing food products therein, in this case pieces of bread, as well as closing means 3a, 3b for closing said opening A Once the food products are housed inside the room.

As can be seen in Figure 1, the container 1 comprises containers 2 that are permeable to air and that house inside a preservative agent protective against moisture (desiccant) suitable for food contact, where the containers 2 are attached to some of the walls of the container, in the particular case of the figure, attached to the walls 1a, 1b, 1c, 1d and 1e (in the last two, they are not seen in the view presented).

The present inventors have carried out experiments, emulating prototypes of the package proposed by the first aspect of the present invention, which will be described below.

Experimental procedures and devices:

i. Testing of moisture measurements and resistance to compression:

The experimentation includes a wide bell using traditional bread bars of a certain quality on which measurements have been made of variation of moisture content of the crumb and of the crust as well as of mechanical resistance to the compression-flexion of the pieces of bread (by means of a test set up for the case), with the time elapsed since the baking, in controlled humidity environments.

Equipment and materials used: plastic or waterproofed porespan box, with variable humidity environments in the range 30-90%, by means of saturated saline solutions, providing certain equilibrium humidities, digital thermo-hygrometer to control relative humidity in the device, penetrometer (Fachini brand, cylindrical indentation of 6.65 mm in diameter) for measurement of resistance to compression (in the range of 0.1 to 1.8 Kg / cm2), cloth bags, envelopes containing dry active material, analyzer of humidity (Ohaus model, MB35).

In porespan boxes (20x20x25 cm3), with external waterproofing and hermetic sealing, a pre-set humidity was established, incorporating a receptacle containing saturated solution of a salt whose equilibrium moisture was the desired for the experiment. During the realization of the experiment the temperature and humidity were measured by thermo-hygrometer digital resident in the box of porespan.

Each box contains a cage of 14 x 22 x 6 cm3, that is to say of volume approximately equal to half the useful volume of a conventional bag used to house three or four "quarter" bars (approximately 4000 cm3), in which a cloth bag containing half a loaf of bread inside it was attached. The test box with controlled humidity had an internal volume of 10000 cm3. For each condition of humidity, and for each active agent, the experiment was carried out with half a bar in a bag located in the cage, in the lower part of the cloth bag and inside the cage, a paper envelope containing the agent was placed active agent, that is to say the preservative agent, and on the cloth bag and in contact with it, another paper envelope containing the active agent was also placed. The initial weight of the active material was preset (75 g, for the case of sepiolite), and it was verified in all cases that the sorption of water vapor in the active agent at three hours after the start of the experiment had been equal to or greater than 9 hours. % in weigh. Under the same conditions the experiment was carried out in white, with another box of analogous porespan, but without incorporating the active agent.

Experimental development carried out:

Two active agents were used, formed by clay minerals selected from two groups: the smectites and the paligorskite-sepiolite (with extensive production in Spain) and experiments were carried out at two humidities representative of very unfavorable conditions for the maintenance of the crunchiness. With successive measurements at the four times indicated above.

At times 1, 2, 3 and 4 (corresponding to 2, 5, 10 and 24 hours after baking) moisture measurements were made in crumb and bark, as well as compression resistance. For each time, 4 moisture measurements were made (three in crust and one in crumb, in 0.7 g portions), and 12 in compression resistance. The moisture determinations obtained by weight loss at 130 ° C for 20 minutes, in portions of 0.55 g.

A procedure for measuring resistance to penetration, by measuring the resistance to compression of the piece of bread, with a suitable distance between supports was developed. The measurement obtained does not correspond in a strict sense to a resistance to compression but to compression - flexion with low deformation.

This measurement of resistance to penetration was made using a pocket penetrometer in the flat part, in its central part, away from the ends, making the perforations along 15-18 cm, supporting the piece at a convenient distance ( 2 cm), and keeping the piece supported with one hand during the performance of the test.

The piece of bread with a gummy (inadequate) behavior is characterized by a high content of moisture in the crumb, as well as by not perceiving the crispy sound during the perforation with the penetrometer and by acquiring, the piece, a high resistance to perforation (at time 4) caused by the loss of the fragile behavior of the crust (deformation prior to perforation).

After carrying out testing of the compression device, different tests were carried out. Figures 2 and 3 exemplify the most frequent types of evolution of resistance to compression Rc (kg / cm2) with the time elapsed after baking, t (1, 2, 3 and 4 corresponding to 2, 5, 10 and 24 hours respectively) recognized in a wide range of tests (30). In both figures, resistances are compared to variable time, with preservative agent (Rc_cort_c) and without preservative agent (Rc_cor_s), in extreme humidity condition (HR = 85%), for different pieces of bread. At time 3 it is perceived organoleptically (oldo and touch) maintenance of the piece's crispness, the value of Rc may be lower or higher than time 2 (with addition, always higher, without addition, not always). At time 4 the increase in value of Rc with respect to the value measured at time 3 is always appreciated, in experience without active agent while in pieces with active agent the opposite occurs.

In these experiments, moisture values of crumb are decreasing, and those of bark increasing (this last in greater measure in the samples without active agent), which justifies the increase in measured resistance that translates the fragile elastic behavior of the piece.

The differences in mechanical behavior are quite clear.

ii. Crucibility tests:

Additionally, in a set of bars, preserved under conditions of extraordinary humidity (HR = 85%) and normal humidity (HR = 40%), in devices located in the laboratory (incorporating or not the preservative agent), and at different times from the baking, a crujibilidad test has been practiced by the simultaneous test of dynamic puncture and sound measurement (TA XTplus equipment, Stable Micro Systems).

The experiments have been carried out for a container consisting of a cardboard box enclosing a volume determined by rectangular faces of approximate dimensions A: 30 cm x 45 cm (2 faces), B: 7 cm x 45 cm (2 faces) and C : 7 cm x 30 cm (2 sides), for horizontal arrangement parallel to the A faces, and with 300 g of sepiolite.

For a more complete description of the phenomenon, the crustability tests described here (carried out in conserved pieces with or without a preservative, and in an environment of normal humidity or extraordinary humidity) were carried out with dynamic penetration and simultaneous measurement of acoustic signals in a TA texturometer. XT Plus, working with a cylindrical probe (contact area 3 mm2), according to the procedure based on the work of Van Hecke E., Alaf AK, and Bouvier JM, 1998. Texture and structure of crispy - puffed food products, part II: Mechanical properties in puncture. Journal of Texture Studies 29 (1998) 617-632. The results obtained are shown in the following two tables, for two bars, identified as bar A, with a bark thicker than 1 mm, and bar B, with a bark thicker than 1 mm, for eight tests EN ° 1 to EN ° 8, referenced respectively as A0, A5S, A5C, B5S, B10C, B10C, A24S, B24S.

Table 1a

Table 1b

Table 1a includes characteristics of bread piece tested, and table 1b summarizes the sonic effects recorded in the dynamic penetration test, when measuring the breaking load (whose value is not included in the table).

Table 1b includes the value of the intensity in decibels of the main sonic effect recorded up to 5 seconds (S to AT = 5 sg), as! as if they were recorded or not, additional distinguishable sonic effects of the fund (whose intensity in decibels is included in the Fund column).

With this experiment, it is shown by tests 2 and 3 (references A5S and A5C) that at 5 hours, with active agent, and extraordinary humidity environment (test 3), the crunchiness is maintained with extraordinary humidity (since it is presented main sonic effect clearly resolved with respect to the background, also appreciable secondary effects differentiable from the background) similar to that recognized in the test 2 for analogous bar with normal humidity.

On the other hand, tests 5 and 6 allowed us to appreciate the maintenance of sonic effects, secondary differentiable from the bottom, more evident in the bar with greater bark thickness (essay 5).

The results obtained validate the efficacy of the active agent in the maintenance of the crujibildad of the piece of bread, maintaining a moisture of the admissible crumb (obviously drying the fresh bread until bread "hard", dry both bark and crumb, the crust increases its mechanical resistance but also the crumb, and the nature of the product is changed). The comparison of tests 2 and 5, or 4 and 6, in terms of moisture data, shows a reduction in the moisture content of the crust, with little variation in the moisture content of the crumb, which translates a certain compositional constancy during the 12-hour interval in which consumption is usually made (breakfast, lunch, snack, dinner) of daily bread.

A person skilled in the art could introduce changes and modifications in the described embodiment examples without departing from the scope of the invention as defined in the appended claims.

Claims (20)

1. - Container (1) applicable to the deposit and conservation of food products, comprising walls (1a, 1b, 1c, 1d, 1e, 1f) arranged so as to define an enclosure with at least one opening (A) for the introduction of food products inside, where at least part of said walls (1a, 1b, 1c, 1d, 1e, 1f) allow the passage of air through the wall to aerate the container, the container being characterized in that at least one of its walls (1a, 1b, 1c, 1d, 1e, 1f) contains, in its interior or attached to one of its faces, at least one preservative agent that protects against moisture and is suitable for food contact. 2. - Container (1) according to claim 1, comprising at least one element (2) including said preservative and which is attached to at least one side of said wall (1a, 1b, 1c, 1d, 1e) , 1f), which is at least one. 3. - Container (1) according to claim 2, comprising a plurality of said elements (2) attached to faces of some or all said walls (1a, 1b, 1c, 1d, 1e, 1f). ^{4. - Container (1) according to re} v ^{indication 2 or 3, wherein said or said faces are} internal faces of the walls (1a, 1b, 1c, 1d, 1e, 1f) of the container (1) that delimit to said enclosure. ^{5. - Container (1) according to re} v ^{indication 2 or 3, wherein said or said faces are} external faces of the walls (1a, 1b, 1c, 1d, 1e, 1f) of the container (1). 6. - Container (1) according to any one of claims 2 to 5, wherein said element (2) is an air-permeable container that houses said preservative agent inside. ^{7. - Container (1) according to re} v ^{indication 1, wherein said preservative agent} is integrated into said wall (1a, 1b, 1c, 1d, 1e, 1f), which is at least one. ^{8. - Container (1) according to re} v ^{indication 7, in which the preservative agent is} incorporated in the composition or structure of said wall (1a, 1b, 1c, 1d, 1e, 1f), which is the minus one. 9. - Container (1) according to any one of the preceding claims, comprising closing means (3a, 3b) to close said opening (A) once the food products are housed inside said enclosure. 10. - Container (1) according to any one of the preceding claims, wherein at least part of said walls (1a, 1b, 1c, 1d, 1e, 1f) are made of an air permeable material allowing the passage of air through the wall. 11. - Container (1) according to claim 10, wherein said walls (1a, 1b, 1c, 1d, 1e, 1f) are made of at least one of the following materials: cardboard, paper or cloth. 12. - Container (1) according to any one of claims 1 to 9, wherein at least part of said walls (1a, 1b, 1c, 1d, 1e, 1f) comprise or define orifices or holes that allow the passage of air through the wall. 13. - Container (1) according to claim 12, wherein said walls (1a, 1b, 1c, 1d, 1e, 1f) are made of at least one of the following materials: wicker, woven, metal, wood or plastic . 14. - Package (1) according to any one of the preceding claims, wherein said preservative comprises at least one microporous substance with high water vapor sorption capacity for environments of relative humidity greater than 50%, resulting in sufficient values higher to 11% by weight. 15. - Package (1) according to claim 14, wherein said substance with high sorption capacity is selected from at least one of the following groups: I. Mineral substances with predominance of phyllosilicates of the following groups of the classification of phyllosilicates of the AIPEA: sepiolite - paligorskite, smectites, vermiculites, when they present clay size and high specific surface, minerals of clay interbedded with smectite sheets, in size clay and high specific surface, and illites, sericites, and minerals with basic structure of sheets 2: 1 presenting high contents of smectite sheets and high specific surface; II. Mineral substances with a predominance of diatomite, with or without thermal treatment; III. Pillared clays, synthesized by insertion by ion exchange of voluminous metal polycations and additional treatment; IV. Natural or synthetic mineral substances from the group of zeolites, preferably those classified as 4 A and 3 A; V. Gels of silica and dried alumina gels; SAW. Other non-hygroscopic moisture sorbents. 16. Container (1) according to any one of the preceding claims, applicable to the storage and preservation of bakery and pastry products that have crispness properties. 17. Container (1) according to claim 16, applicable to the storage and preservation of pieces of bread. 18. - Packaging (1) according to any one of the preceding claims, provided in the form of a box, bag or sack. 19. Container (1) according to any one of the preceding claims, wherein the moisture protection properties of said preservative are regenerable when subjected to a temperature below 200 ° C. 20. - Use of a preservative agent, protector against moisture and suitable for food contact, for the preservation of food products deposited inside an air permeable container defined according to any one of the preceding claims.