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
  • A23L3/36—Freezing; Subsequent thawing; Cooling
  • A23L3/365—Thawing subsequent to freezing
• • A—HUMAN NECESSITIES
  • A23—FOODS OR FOODSTUFFS; TREATMENT THEREOF, NOT COVERED BY OTHER CLASSES
  • A23B—PRESERVING, e.g. BY CANNING, MEAT, FISH, EGGS, FRUIT, VEGETABLES, EDIBLE SEEDS; CHEMICAL RIPENING OF FRUIT OR VEGETABLES; THE PRESERVED, RIPENED, OR CANNED PRODUCTS
  • A23B4/00—General methods for preserving meat, sausages, fish or fish products
  • A23B4/06—Freezing; Subsequent thawing; Cooling
  • A23B4/07—Thawing subsequent to freezing
• • H—ELECTRICITY
  • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
  • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
  • H05B6/00—Heating by electric, magnetic or electromagnetic fields
  • H05B6/64—Heating using microwaves
  • H05B6/66—Circuits
  • H05B6/68—Circuits for monitoring or control
  • H05B6/688—Circuits for monitoring or control for thawing
• • H—ELECTRICITY
  • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
  • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
  • H05B6/00—Heating by electric, magnetic or electromagnetic fields
  • H05B6/64—Heating using microwaves
  • H05B6/78—Arrangements for continuous movement of material
  • H05B6/782—Arrangements for continuous movement of material wherein the material moved is food

Definitions

• the present invention relates to the field of defrosting food products by microwave technology. It is particularly interested in defrosting processes for defrosting foods in the form of large pieces or blocks, for example blocks of fish or meat mass greater than about 20 or 30 kilograms.
• One of the objectives of the present invention is to provide good control of the temperature to ensure homogeneous core and surface temperatures while avoiding hot spots ("HOT SPOTS").
• the present invention relates to a new method of defrosting food products by microwave technology whose characteristics can be summarized as follows: the product is brought into contact with CO 2 under the a snow that looks like tiny particles (typically the size of the laundry powder) these particles being charged with static electricity.
• the size of such particles is typically of the order of a few hundred microns, for example close to 500 microns.
• the present invention seeks to cover the surface of the product with a film of dry ice in the form of such electrostatically charged microparticles, and it is found in practice that such conditions make it possible to reduce the temperature rise. achieve an excellent coverage, not only of the faces of the blocks but also of their edges, which the methods of the prior art fail to do, and this is a fundamental point to avoid dissipating microwaves to the surface but also to eliminate hot spots. It is thus particularly advantageous to set up a homogeneous carbon dioxide film that covers the entire outer surface of the product.
• a feed is typically fed with liquid CO 2 , which in turn feeds a series of blunderbusses with solenoid valves or calibrated orifices.
• the present invention thus relates to a method for thawing food products of the type implementing the action, in a chamber where the products transit, of at least one microwave radiation applicator, characterized in that prior to its entry into the chamber or in a first inlet zone of the chamber, all the surfaces of the product are covered with a homogeneous film of dry ice in the form of electrostatically charged microparticles.
• one or more cyclonic type apparatuses centrrifugation with a convergent cone of polymer material will preferably be used.
• the conveyor is moved back a step to bring this film with respect to a product deposition system and is deposited a product (i + 1) on the snow film (i + 1) previously filed ;
• a step is taken backwards to put the product (i + 1) facing the cyclone and to deposit a snow deposit on the product (i + 1) and the deposition of a product (i) on the film (i) ;
• the conveyor is moved back a step, to deposit a product (i-1) on the film (i-1), and deposit a snow deposit on the product (i) ...
• one or more production units are used and application of dry ice on the cyclonic product provided with a convergent cone of polymer material.
• the conveyor is moved back a step to bring this film (i + 1) with respect to a product deposition system and is deposited a product (i + 1) on the snow film (i +1) previously filed;
• a new snow film (i) is deposited on the conveyor upstream of the preceding product (i + 1); a step is made behind the conveyor to put the product (i + 1) opposite the cyclonic apparatus and deposit a snow deposit on the product (i + 1), and the deposit of a product (i) on the film (i);
• the conveyor is moved back a step, to deposit a product (i-1) on the film (i-1), and deposit a snow deposit on the product (i) and so on.
• said sequencing makes it possible to obtain a residence time of the products in the chamber for 10 to 15 minutes.
• the invention also relates to a device for defrosting food products, of the type comprising, in a room where transit the products, at least one microwave radiation applicator, characterized in that upstream of the entrance of the chamber or inside the chamber in its entry zone, one or more Apparatus (s) for producing and applying a homogeneous dry ice film to the surfaces of the product, the dry ice being in the form of electrostatically charged microparticles.
• the device according to the invention can adopt one or more of the following characteristics:
• a single device for producing and applying CO 2 of the cyclonic type positioned upstream of the opening of the chamber or in the chamber itself in its entry zone above the conveyor, and includes a conveyor advancement control system for passing products into the chamber, a control system capable of enabling the following sequencing:
• FIG. 1 schematically represents a device enabling the implementation of FIG. the invention, comprising a single device of cyclonic type, positioned in the chamber itself in its input area above the conveyor.
• - Figure 2 schematically shows a device for implementing the invention, comprising two devices cyclonic type, the first is positioned upstream of the chamber and the loading area of the product, to uniformly cover the conveyor by a snow film, the second cyclonic device is positioned in the entrance zone of the chamber, just after the entry of the product.
• - Figure 3 schematically illustrates the sequencing of the advance of the conveyor according to the invention using a single cyclonic device.
• FIG. 1 shows a tunnel for defrosting foodstuffs continuously, comprising at least one microwave radiation applicator (not shown in the figure so as not to load it but well known to those skilled in the art), plant being provided, upstream of the tunnel entrance, with a device (D) for depositing products, as well as with a cyclonic apparatus (C) for producing and applying a film of dry ice on the surface of the product located inside the tunnel in its zone of entry.
• a microwave radiation applicator not shown in the figure so as not to load it but well known to those skilled in the art
• FIG. 2 illustrates another embodiment of the invention implementing two cyclonic-type devices, the first one being positioned upstream of the chamber and the loading zone of the product.
• the second cyclonic apparatus is positioned inside the chamber, in its entry zone, just after the entry of the product.
• the advance of the conveyor can be done continuously forward, the dosage of the film thickness is achieved by the speed of the conveyor and the amount of snow injected.
• FIG. 3 for its part, makes it possible to better visualize a mode of sequencing the treatment of the products according to the invention, using a single cyclonic device for producing CO 2 particles (whether it is located upstream of the entrance or inside the tunnel), one thus visualizes well the following operations on the 3 stages 1/2 / and 3 / of this figure:
• Step 2 a step was made behind the conveyor to put the product (i + 1) opposite the cyclone apparatus (C) and deposit a snow deposit on the product (i + 1) and in this same position is deposited a product (i) on the film (i);
• Tested product Blocks of fish fillets (initial temperature of -18 ° C, dimensions 255x485x60 mm).
• CO? ⁇ for a first test, comparative, we used mini-sticks of CO 2 of diameter close to 2mm.
• Dry Ice and Microwave To evaluate the behavior of dry ice (CO 2 ) in the presence of microwaves, we have introduced 500g of dry ice for 15 minutes in a microwave cell and we compared the weight loss compared to 500g of dry ice outside the cell. The result showed that the microwave oven does not heat dry ice. His weight has not changed.
• the results obtained under such conditions in accordance with the invention are firstly that the temperature between the core and the surface remains homogeneous and secondly that the formation of hot spots on the surface of the product is avoided.

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• Life Sciences & Earth Sciences (AREA)
• Engineering & Computer Science (AREA)
• Physics & Mathematics (AREA)
• Electromagnetism (AREA)
• Chemical & Material Sciences (AREA)
• Food Science & Technology (AREA)
• Polymers & Plastics (AREA)
• Wood Science & Technology (AREA)
• Zoology (AREA)
• Health & Medical Sciences (AREA)
• Nutrition Science (AREA)
• Freezing, Cooling And Drying Of Foods (AREA)

Applications Claiming Priority (2)

Publications (1)

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• 2008
  • 2008-03-10 FR FR0851514A patent/FR2928245B1/fr not_active Expired - Fee Related
• 2009
  • 2009-03-03 US US12/921,900 patent/US8465784B2/en not_active Expired - Fee Related
  • 2009-03-03 EP EP09723422A patent/EP2262374A2/de not_active Withdrawn
  • 2009-03-03 WO PCT/FR2009/050342 patent/WO2009115723A2/fr active Application Filing
  • 2009-03-03 JP JP2010550237A patent/JP2011512858A/ja active Pending

Non-Patent Citations (1)

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