Classifications

• • A—HUMAN NECESSITIES
  • A23—FOODS OR FOODSTUFFS; TREATMENT THEREOF, NOT COVERED BY OTHER CLASSES
  • A23L—FOODS, FOODSTUFFS, OR NON-ALCOHOLIC BEVERAGES, NOT COVERED BY SUBCLASSES A21D OR A23B-A23J; THEIR PREPARATION OR TREATMENT, e.g. COOKING, MODIFICATION OF NUTRITIVE QUALITIES, PHYSICAL TREATMENT; PRESERVATION OF FOODS OR FOODSTUFFS, IN GENERAL
  • A23L3/00—Preservation of foods or foodstuffs, in general, e.g. pasteurising, sterilising, specially adapted for foods or foodstuffs
  • A23L3/02—Preservation of foods or foodstuffs, in general, e.g. pasteurising, sterilising, specially adapted for foods or foodstuffs by heating materials in packages which are progressively transported, continuously or stepwise, through the apparatus
  • A23L3/04—Preservation of foods or foodstuffs, in general, e.g. pasteurising, sterilising, specially adapted for foods or foodstuffs by heating materials in packages which are progressively transported, continuously or stepwise, through the apparatus with packages on endless chain or band conveyors
• • A—HUMAN NECESSITIES
  • A23—FOODS OR FOODSTUFFS; TREATMENT THEREOF, NOT COVERED BY OTHER CLASSES
  • A23L—FOODS, FOODSTUFFS, OR NON-ALCOHOLIC BEVERAGES, NOT COVERED BY SUBCLASSES A21D OR A23B-A23J; THEIR PREPARATION OR TREATMENT, e.g. COOKING, MODIFICATION OF NUTRITIVE QUALITIES, PHYSICAL TREATMENT; PRESERVATION OF FOODS OR FOODSTUFFS, IN GENERAL
  • A23L3/00—Preservation of foods or foodstuffs, in general, e.g. pasteurising, sterilising, specially adapted for foods or foodstuffs
  • A23L3/10—Preservation of foods or foodstuffs, in general, e.g. pasteurising, sterilising, specially adapted for foods or foodstuffs by heating materials in packages which are not progressively transported through the apparatus
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
  • B65B—MACHINES, APPARATUS OR DEVICES FOR, OR METHODS OF, PACKAGING ARTICLES OR MATERIALS; UNPACKING
  • B65B25/00—Packaging other articles presenting special problems
  • B65B25/001—Packaging other articles presenting special problems of foodstuffs, combined with their conservation
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
  • B65B—MACHINES, APPARATUS OR DEVICES FOR, OR METHODS OF, PACKAGING ARTICLES OR MATERIALS; UNPACKING
  • B65B29/00—Packaging of materials presenting special problems
  • B65B29/08—Packaging of edible materials intended to be cooked in the package
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
  • B65B—MACHINES, APPARATUS OR DEVICES FOR, OR METHODS OF, PACKAGING ARTICLES OR MATERIALS; UNPACKING
  • B65B51/00—Devices for, or methods of, sealing or securing package folds or closures; Devices for gathering or twisting wrappers, or necks of bags
  • B65B51/10—Applying or generating heat or pressure or combinations thereof
  • B65B51/14—Applying or generating heat or pressure or combinations thereof by reciprocating or oscillating members
  • B65B51/146—Closing bags
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
  • B65D—CONTAINERS FOR STORAGE OR TRANSPORT OF ARTICLES OR MATERIALS, e.g. BAGS, BARRELS, BOTTLES, BOXES, CANS, CARTONS, CRATES, DRUMS, JARS, TANKS, HOPPERS, FORWARDING CONTAINERS; ACCESSORIES, CLOSURES, OR FITTINGS THEREFOR; PACKAGING ELEMENTS; PACKAGES
  • B65D77/00—Packages formed by enclosing articles or materials in preformed containers, e.g. boxes, cartons, sacks or bags
  • B65D77/22—Details
  • B65D77/225—Pressure relief-valves incorporated in a container wall, e.g. valves comprising at least one elastic element
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
  • B65D—CONTAINERS FOR STORAGE OR TRANSPORT OF ARTICLES OR MATERIALS, e.g. BAGS, BARRELS, BOTTLES, BOXES, CANS, CARTONS, CRATES, DRUMS, JARS, TANKS, HOPPERS, FORWARDING CONTAINERS; ACCESSORIES, CLOSURES, OR FITTINGS THEREFOR; PACKAGING ELEMENTS; PACKAGES
  • B65D81/00—Containers, packaging elements, or packages, for contents presenting particular transport or storage problems, or adapted to be used for non-packaging purposes after removal of contents
  • B65D81/34—Containers, packaging elements, or packages, for contents presenting particular transport or storage problems, or adapted to be used for non-packaging purposes after removal of contents for packaging foodstuffs or other articles intended to be cooked or heated within the package
  • B65D81/3446—Containers, packaging elements, or packages, for contents presenting particular transport or storage problems, or adapted to be used for non-packaging purposes after removal of contents for packaging foodstuffs or other articles intended to be cooked or heated within the package specially adapted to be heated by microwaves
  • B65D81/3461—Flexible containers, e.g. bags, pouches, envelopes
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
  • B65D—CONTAINERS FOR STORAGE OR TRANSPORT OF ARTICLES OR MATERIALS, e.g. BAGS, BARRELS, BOTTLES, BOXES, CANS, CARTONS, CRATES, DRUMS, JARS, TANKS, HOPPERS, FORWARDING CONTAINERS; ACCESSORIES, CLOSURES, OR FITTINGS THEREFOR; PACKAGING ELEMENTS; PACKAGES
  • B65D81/00—Containers, packaging elements, or packages, for contents presenting particular transport or storage problems, or adapted to be used for non-packaging purposes after removal of contents
  • B65D81/18—Containers, packaging elements, or packages, for contents presenting particular transport or storage problems, or adapted to be used for non-packaging purposes after removal of contents providing specific environment for contents, e.g. temperature above or below ambient
  • B65D81/20—Containers, packaging elements, or packages, for contents presenting particular transport or storage problems, or adapted to be used for non-packaging purposes after removal of contents providing specific environment for contents, e.g. temperature above or below ambient under vacuum or superatmospheric pressure, or in a special atmosphere, e.g. of inert gas
  • B65D81/2007—Containers, packaging elements, or packages, for contents presenting particular transport or storage problems, or adapted to be used for non-packaging purposes after removal of contents providing specific environment for contents, e.g. temperature above or below ambient under vacuum or superatmospheric pressure, or in a special atmosphere, e.g. of inert gas under vacuum
  • B65D81/2023—Containers, packaging elements, or packages, for contents presenting particular transport or storage problems, or adapted to be used for non-packaging purposes after removal of contents providing specific environment for contents, e.g. temperature above or below ambient under vacuum or superatmospheric pressure, or in a special atmosphere, e.g. of inert gas under vacuum in a flexible container

Definitions

• the present invention relates to a method for heating and packaging a consumable product, in particular a food product, in a packaging, process by which said product is introduced into the packaging and the product is heated.
• Heating the product is used in particular to promote its conservation. It can be a simple cooking, complete or partial, or else pasteurization, or even sterilization.
• pasteurization makes it possible to destroy certain bacteria by heating.
• this product can be brought to a temperature of 80 ° C to 100 ° C, for a given time, for example of the order of 3 to 5 min, so as to give it a date consumption limit of 20 days after this treatment.
• this expiration date can be extended to a much longer period, for example of the order of one year, by bringing the product to a higher temperature, for example of the order of 120 ° C. , for the time necessary, for example of the order of 3 to 5 min.
• the consumable product is in particular a food product, such as vegetables, fruit or other fresh, blanched or precooked, or frozen food. It can also be ready meals, taking for example meat or fish, or any food preparation.
• the packaging may in particular be a tray, or else a flexible pouch. It is advantageously made of plastic or composite, allowing heating by microwaves.
• the product is packaged in this packaging, in which it can be kept for some time. Depending on the case, it can, when the packaging is opened, be consumed as a fresh product or as a cooked or precooked product. It can be reheated before consumption, without necessarily being removed from the packaging at the same time.
• a vapor is produced, which puts the interior of the packaging under pressure.
• Various possibilities are known for preventing this overpressure from leading to a bursting of the packaging and to a failure of the heating process.
• FR-A-2 635 760 recommends the adaptation on the packaging of a valve formed of a composite resin which becomes porous when the temperature reaches a certain value, thus allowing the evacuation of excess gases during heating.
• FR-A-2 695 108 recommends making a hole in the packaging and placing on this hole a portion of sheet sealed with a special adhesive, which allows the lifting of this portion of sheet when, during heating, the overpressure in the packaging becomes too great.
• WO 91/01927 proposes to use a packaging, the sealing of which has a zone of partial interruption, covered with a coating, for example of adhesive, which melts during heating, so as to allow a reduction in the overpressure in the packaging, and which solidifies upon cooling so as to close the packaging.
• the present invention proposes to provide a much simpler and effective solution to the problem of overpressure which occurs inside the packaging during heating.
• This object is achieved thanks to the fact that, after having introduced the product into the packaging, the latter is partially closed while preserving at least one temporarily non-welded area between two walls of the packaging, the product is partially heated in the packaging closed, then the packaging is completely closed by welding said walls in said zone.
• the area left temporarily welded is sealed between the two walls of the package, and it is very easily ensured that this area is perfectly sealed, so as to completely close packaging.
• this weld can extend not only over the area left temporarily unwelded, but also slightly beyond.
• the product is introduced into the packaging through an opening formed between said walls and the packaging is partially closed by welding said walls to a part of said opening and preserving said temporarily non-welded area on a remaining part of the opening.
• the packaging may for example be a flexible rectangular pocket, welded on three sides, but one side of which, through which the product has been introduced into the packaging, has remained unwelded.
• a rigid or semi-rigid tray Initially, this tray can be opened on one of its faces. After the product has been placed in said tray, a cover (for example constituted by a flexible sheet or by a rigid or semi-rigid plate, possibly formed from the same material as the tray) can be placed across this face so that to cover it entirely, but only to be welded to the rim of the tray on most of its outline, leaving a small part that is not welded, which will only be welded after the product has heated up.
• the dimensions of the temporarily welded zone or zones are chosen so that the vapor released by the contents of the packaging during heating causes an overpressure inside said packaging. It is for example advantageous that this overpressure is at least substantially equal to 0.2 bar, preferably 0.4 bar.
• maintaining a certain overpressure can in fact promote the heating and cooking of the product contained in the packaging.
• the stage in which we completely close the packaging is carried out immediately after heating, while a slight overpressure (advantageously at least 0.2 bar, or even at least 0.4 bar) still prevails in this packaging, so as to avoid any risk of contamination of the contents of the packaging by products outside of the latter.
• the consumable product and an additional liquid are introduced into the packaging.
• an aqueous liquid pure water or water with one or more additives which can, for example, be chosen from dyes, preservatives, flavoring agents, perfumes, fatty substances. emulsified.
• a nonaqueous liquid for example alcohol, can also be used. It is preferably a liquid which vaporizes during heating, the latter generally occurring at a temperature below 150 ° C. During heating, this liquid vaporizes very quickly and the steam thus generated, which quickly creates an overpressure, promotes the cooking of the product contained in the packaging.
• adding a liquid to the packaging before heating is particularly advantageous when this heating is carried out by microwaves.
• the contents of the packaging are suddenly cooled after having completely closed the latter.
• An abrupt cooling makes it possible to stop the cooking of the product, to obtain exactly the desired cooking, while minimizing the degradation of the organoleptic properties of the product.
• At least one of the walls can be formed by a flexible film. This film tends to deform during heating to allow an increase in the interior volume of the packaging, but, during sudden cooling, it tends to shrink, thereby reducing the volume of the packaging and facilitating its subsequent handling.
• said walls are welded along a weld line having an interrupted area.
• the walls are welded along a first weld line having a first interrupted face and along a second weld line, distant from the first weld line and having a second interrupted face, said first and second interrupted areas being offset.
• the invention also relates to an installation for heating and packaging a consumable product, in particular a food product, in a package, comprising a heating station and drive means capable of driving the product contained in the package into the installation. .
• the object of the invention is to propose an installation of this type, making it possible in a simple way to avoid or, at least, to considerably limit, the harmful effects of an excessive overpressure inside the packaging during heating. .
• the installation according to the invention comprises, arranged upstream of the heating station in the direction of advancement of the drive means, partial closing means capable of partially closing the packaging while preserving at least one temporarily non-welded zone between two walls of the packaging and, arranged downstream of the heating station, complementary closing means capable of welding said walls in said zone.
• the packaging containing the consumable product is driven step by step in the various stations of the installation.
• the installation comprises, arranged upstream of the heating station, means for introducing the product through an opening formed between two walls of the packaging, and the partial closing means are capable of welding together said walls in a part. of the opening while preserving said temporarily non-welded area on a remaining part of the opening.
• the invention also relates to a packaging containing a consumable product, in particular a food product which has undergone heating.
• the object of the invention is to propose a packaging making it possible to avoid or, at least, to considerably limit, the harmful effects of an overpressure inside the packaging when the product it contains is heated.
• the packaging according to the invention has at least two walls welded along at least one partial weld line preserving an area initially not welded along said line and according to at least one complementary weld area, connected to said partial seal line and extending across said initially non-welded area so as to completely close the package.
• the complementary weld line is made, across the non-welded area of the partial weld line, after the product contained in the packaging has been heated.
• the non-welded zone of the partial weld line forms part of a passage in the form of a baffle capable of allowing, before the completion of the complementary weld line, communication between the interior space of the packaging and the outside.
• the packaging has a first and a second partial weld line spaced from each other and preserving, respectively, a first and a second zone which is not welded along the line considered, and at least one complementary weld zone. connected to the first seal line and extending across the first zone so as to completely close the package, said first and second zones being offset.
• FIG. 6A is a section along the line VIA-VIA of Figure 6;
• FIG. 7 shows, according to a variant, a partial weld of the packaging before heating
• FIG. 9 shows a package of the type of a tray which can also apply the method according to the invention.
• the package 10 for example consisting of a flexible bag, has an opening 12 formed between its walls 10A and 10B.
• a consumable product for example pieces of vegetables 14, is introduced into this packaging through the opening 12.
• FIG. 2 shows the pocket 10 partially closed. Indeed, the two walls 10A and 10B are welded together across the opening 12 by two weld lines 16A and 16B, between which a temporarily non-welded area 17 is preserved.
• the two portions 16A and 16B are two portions of the same rectilinear welded zone, interrupted locally. Of course, not one, but several temporarily non-welded areas could be preserved.
• a liquid 18 was introduced into the pocket.
• the product 14 and the liquid 18 are introduced through the opening 12, and it is across this opening that the pocket is then partially welded. It can also be provided that the pocket is present in another region, for example in zone Z indicated in FIG. 1, a local interruption in the welding of its walls, and that, after the introduction of the product 14 and, where appropriate, that of the liquid 18, this opening is completely closed by welding.
• the bag containing the product is ready to undergo heating.
• Figure 3 shows the situation of the bag during heating. Under the effect of heating, the pressure inside the pocket increases, in particular due to the evaporation of water due to the increase in temperature.
• the water which evaporates can come entirely from the consumable product 14 (it can for example be fresh or semi-fresh vegetables having a certain water content) or else it can also come from the liquid 18 when it is an aqueous liquid.
• the vapor 18 'fills the interior space of the pocket and, the vaporization increasing as the temperature rises, the walls 10A and 10B of the pocket deform so as to allow an increase in its volume.
• the excess steam escapes through the opening 17A formed between the walls 10A and 10B due to the presence of the temporarily non-welded zone 17.
• the dimension of this zone is small enough that, while allowing evacuation of the excess vapor pressure, it allows the establishment of an overpressure inside the pocket. Indeed, such an overpressure of vapor promotes heating.
• FIG. 4 shows the bag after heating. It can be seen that, instead of the temporarily non-welded zone 17, a weld 17 ′ has been made so as to completely close the pocket.
• FIG. 5 shows an installation for implementing the method of the invention.
• the package 10 is formed from a film tube 8, retained on a hollow support 20, also tubular. The lower end of the tube 8 is closed; it is in the lower part that the packaging will be formed 10. Firstly, through the interior of the support 20, the consumable product 14 initially contained in a reservoir 26 or the like, as well as the liquid initially contained in a reservoir 28 are poured into the lower part of the tube 8.
• the installation comprises partial closing means such as two welding electrodes 34A and 34B able to pinch between them the walls 10A and 10B, across the opening 12. These welding electrodes have an interrupted area so as, during this welding, to preserve an unwelded area of the type of the area 17 shown in the figures 2 and 3.
• cutting tools 33A and 33B can be activated to cut the lower part of the tube 10, just above the welding produced by the electrodes 34A and 34B, so as to form a package 10.
• D other closing means such as welding electrodes 32A and 32B can be activated, for example at the same time as the electrodes 34A and 34B, to weld the two walls of the tube 8 against each other, above the cutting made by the tools 33A and 33B.
• the welding carried out by these electrodes 32A and 32B achieves a complete closure of what, after cutting by the tools 33A and 33B, will become the new lower end of the tube 8.
• This first station 21 comprises means such as a vibrating conveyor belt 20A, which serves to distribute the contents of the bag homogeneously inside the latter, which is then placed flat.
• the pocket can also be pivoted by 90 ° in a horizontal plane so that the weld lines at its two ends which, in the position of the pocket shown in station 21, extend perpendicular to the plane of Figure 6, either oriented parallel to this plane.
• the bag is taken up by a new conveyor 20B which, advancing in direction F, drives it into a heating station 36 advantageously comprising an enclosure 37 for heating by microwaves.
• a microwave generator 38 disposed inside this enclosure 37.
• the latter has an inlet and an outlet for the bag 10 which are not shown.
• several pockets can be simultaneously in the enclosure 37.
• the length of the latter and the step of advancement of the conveyor 20B can be adjusted so that the duration of parking of a pocket 10 in the enclosure 36 is sufficient to allow the desired heating.
• the installation Downstream of the heating station 36, the installation comprises a complementary closing station 40 in which the pocket is driven by the conveyor 20B.
• This station comprises complementary closing means comprising, for example, welding electrodes 44A and 44B, able to pinch the two walls of the pocket between them across the zone left temporarily not welded by the electrodes 34A and 34B.
• These two electrodes 44A and 44B can be substantially similar to the electrodes 34A and 34B but, unlike the latter, extend over the entire width of the pocket. They may also extend only over the length of the ⁇ ne left provisionally unwelded 17 or, preferably, over a length at least slightly greater.
• the pocket 10 can be arranged so that its end comprising the temporarily non-welded zone protrudes beyond the edge of the conveyor 20B.
• the lower electrode 44B of the additional welding means can therefore be moved without obstacle.
• the installation Downstream of the complementary closing means, the installation includes means for suddenly cooling the contents of the packaging. They include for example a tank 46 containing cold water 48, in which the bag can be immersed. The temperature of the water 48 can be kept sufficiently low by the maintenance of a circulation of water and the use of cooling means not shown.
• tank 46 is simply placed at the end of the conveyor 20, and the packaging 10 naturally falls into this tank at the outlet of the station 40.
• the bag While in station 36, the bag was inflated under the effect of the overpressure generated during heating, it retracts into the tank 46.
• FIG. 7 shows a variant for the partial closure of the pocket 10. It can be seen in this figure that the walls of the pocket are welded along a first weld line 56 having a first interrupted area 57, and along a second line of weld 58, distant from the first line 56 and having a second interrupted area 59. The first and second interrupted areas 57 and 59 are offset from each other.
• the weld lines 56 and 58 are rectilinear, are each formed by two portions of weld lines, respectively 56A, 56B and 58A, 58B, and are parallel to each other.
• the bag 10 is capable of containing 2 kg of potatoes, each of its faces forming a rectangle of approximately 40 cm x 30 cm, the two weld lines are spaced approximately 25 mm apart and the length of each interrupted area 57 and 59 is of the order of 20 mm.
• the partial closure means 34A and 34B of the installation are advantageously able to weld the walls of the packaging according to the weld lines 56 and 58 defined above.
• the welding electrodes 34A and 34B each have two interrupted edge lines in accordance with the zones 57 and 59, the edge lines of the respective electrodes being located opposite each other.
• FIG. 9 shows that the invention applies to the heating of products contained in containers other than flexible bags. It may for example be a tray 60 whose upper opening is covered by a cover 62 which is welded to the tray on its rim 61. However, on a portion 61A of the rim, extending for example over any the width of the tray 60, the welding between the cover 62 and the rim is carried out so as to spare the temporarily non-welded area.
• the weld is similar to that of Figures 7 and 8, and there are the same weld lines 56 and 58 as those which have been described with reference to these figures.
• the two walls of the package between which the temporarily non-welded zone is formed are therefore formed respectively by the part of the rim 61A and the end of the film 62 disposed on this part of the rim.
• the consumable product and, if necessary, the additional liquid can be placed in the tray 60 before the fitting of the cover 62 and its welding as shown in FIG. 9. It is only after heating that the zones temporarily not welded 57 and 59 are completely closed.
• the packaging can be formed by a flexible pocket made of a film of composite or plastic material; whether for example a flexible bag or a tray, it is advantageously made of a material allowing the heating, by microwaves, of the product which it contains.
• this packaging can be formed from polypropylene (PP) or tetrafluorinated polyethylene (PET), polyamide / polyethylene or even polyamide / polypropylene, according to multilayer arrangements.
• the walls between which the temporarily non-welded zone is formed are advantageously made of a material comprising plastics and composite materials capable of being welded by application of heat.
• the packaging When at least part of the packaging is formed by a flexible film (the two walls 10A and 10B of the bag 10 or the cover 62 of the tray 60), the latter tends to deform during heating. Depending on the material used, and depending on the thickness of the film, this deformation is more or less significant and the film becomes more flexible under the effect of the rise in temperature. This can be an advantage because, during the sudden cooling step which follows the total closure of the container, the still flexible film can shrink around the product it contains. This is particularly advantageous when this packaging is formed by a flexible pocket.
• FIG. 10 is a comparative curves relating to tests.
• 2,000 g of peeled potatoes, 55 g in size, of the firm flesh variety type Agatha were placed in a pocket, and 90 g of water were added.
• the welding carried out across the opening of this pocket is interrupted on a temporarily non-welded area 15 mm in length.
• Each pocket wall, made of polyamide / polypropylene multilayer film, having a thickness of 90 ⁇ m and a grammage of 89 g / m 2 (film distributed under the name "CRYOVAC - OP" forms a rectangle of 40 cm x 30 cm.
• Cooking was carried out by applying microwaves, with a power of 3.8 kW for the first 150 seconds (temperature rise time) then, for the remaining 180 seconds (time to maintain temperature), with a power during heating, the ambient temperature inside the pocket ("T ambience" curve) as well as the temperature of a potato located in the center of the pocket and that of a potato are measured. soil located at the edge of the pocket (curves "T produced in the center” and "T produced at the edge).
• the bag After heating, the bag is completely closed as soon as it leaves the microwave enclosure and immersed in a tank of water at 10 ° C for 1 min.
• the weight of the sachet then measured is 2001 g, which represents a loss in mass, essentially due to the evaporation of liquid, of 89 g.
• the potatoes were therefore cooked evenly without drying out.
• 2000 g of potatoes of the same variety are placed in an identical pocket, and the latter is welded so as to provide the same zone which is temporarily not welded.
• the heating is carried out under exactly the same conditions as in FIG. 10 but the water has not been added.
• the three curves reflect temperature measurements taken in the same way as in FIG. 10. It can be seen that these temperatures are much less homogeneous than in FIG. 10. In particular, the temperature of the product at the edge increases too rapidly compared to that of the product in the center, while the ambient temperature remains low for approximately 100 seconds, the time necessary for the generation of vapor from the evaporation of the water contained in the potatoes.
• the bag After heating, the bag is completely closed and cooled under the same conditions as in the test in FIG. 10.
• the mass of the sachet then measured is 1875 g, which corresponds to a loss in mass of 125g.
• the product has dehydrated (the significant loss in mass comes from dehydration), and its appearance is somewhat degraded since the potatoes at the edge of the pocket are overcooked , while those on the edge are not enough.
• the potatoes seem perfectly cooked in a homogeneous manner. Indeed, cooking by microwaves, with the addition of water in the sachet allows to combine the advantages of microwaves and steam. Microwaves heat the liquid very quickly and therefore generate steam in a very short time. The microwaves also heat the product itself to the core. Steam promotes heat transfer and the temperature to which the potatoes are brought is more uniform over their entire thickness.
• the quantity of liquid added can be optimized so that, after total closure and cooling of the package, there is practically no liquid left in the bag, that is to say that most of the liquid has been discharged or permeates the product contained in the packaging, without remaining in the liquid state as such.
• the amount of liquid added advantageously represents, by mass, from 2% to 10% and, preferably, from 4% to 6% of the mass of the products.
• the method according to the invention is perfectly suitable for heating fresh products, for example mixtures of different vegetables, and for heating frozen products used as fresh products.
• the temperature raising step is continued until there is an overpressure inside the packaging.
• the latter is a flexible pocket, this overpressure is simply observed when the volume of this pocket increases sufficiently. The fact that this overpressure is observed makes it possible to ensure that the sachet contains a sufficient quantity of water vapor to carry out the heating under the desired conditions.

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• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Life Sciences & Earth Sciences (AREA)
• Food Science & Technology (AREA)
• Health & Medical Sciences (AREA)
• Nutrition Science (AREA)
• Chemical & Material Sciences (AREA)
• Polymers & Plastics (AREA)
• Packages (AREA)
• Lining Or Joining Of Plastics Or The Like (AREA)
• Package Specialized In Special Use (AREA)

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• 2003
  • 2003-03-24 FR FR0303534A patent/FR2852921B1/fr not_active Expired - Fee Related
• 2004
  • 2004-03-23 WO PCT/FR2004/000711 patent/WO2004085254A2/fr active IP Right Grant
  • 2004-03-23 ES ES200550061A patent/ES2285925B1/es not_active Expired - Fee Related
  • 2004-03-23 CA CA002520003A patent/CA2520003A1/fr not_active Abandoned
  • 2004-03-23 EP EP04742321A patent/EP1615824A2/de not_active Withdrawn
• 2005
  • 2005-09-22 MA MA28509A patent/MA27750A1/fr unknown

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