GB2356550A

GB2356550A - Cooling a bakery product prior to filling it

Info

Publication number: GB2356550A
Application number: GB9924191A
Authority: GB
Inventors: Ray Beazley
Original assignee: J&E Hall Ltd
Current assignee: J&E Hall Ltd
Priority date: 1999-10-07
Filing date: 1999-10-07
Publication date: 2001-05-30
Also published as: GB9924191D0

Description

2356550 TITLE: METHOD AND APPARATUS The present invention relates to a

method and apparatus, notably to a method for preparing bakery foodstuffs and an 5 apparatus for use in that method.

BACKGROUND TO THE INVENTION:

The rate at which bread and bread products go stale when exposed to the air isat a maximum at a temperature of f rom - SIC to + SIC. Bakers therefore seek to pack their products at a temperature of about + 30'C and personal shoppers have come to associate warm bread with fresh baked bread. However, where the bread is used on a commercial scale in the production of sandwiches, the sandwich manufacturer must ensure that the final filled sandwich is at a temperature of less than + SIC in order to meet legislation on the storage and transport of foodstuffs. This requires that the filled sandwich be cooled from its ambient temperature to about + SIC. However, if the sandwich contains temperature sensitive materials, for example lettuce, such cooling must be carried out slowly to minimise thermal damage to those materials. Typically, this cooling of the filled sandwich is carried out in a tunnel cooler through which the sandwiches are transported on a moving belt conveyor. Typically, each filled sandwich is packed into a plastic tray or the like and the tray sealed with a heat sealed cover sheet prior to passing through the cooling tunnel.

Such a process is widely used in the commercial production P2483.Alv1 OctDber 1999 2 of sandwiches. However, it is not feasible rapidly to vary the cooling conditions in the tunnel to suit different fillings in individual sandwiches. The process is thus operated to achieve optimum conditions for long runs of production of sandwiches having the same filling or under cooling conditions which suit the average filling and thus may not be the optimum for some fillings. The residence time of the sandwich in the cooling tunnel also represents a prolongation of the sandwich production process which may limit the throughput of a given assembly of equipment because there is no room to extend the tunnel within the space available to achieve a greater cooling residence time.

We have now devised a method by which the above problems can be reduced and apparatus for use in that method.

SUMMARY OF THE INVENTION:

Accordingly, the present invention provides a method for making a bakery product incorporating a filling, which method comprises pre-cooling the bakery product at a cooling station from its ambient first temperature to a predetermined second lower temperature and at a filling 25 station applying one or more filling materials to the cooled bakery product to produce a filled bakery product having a predetermined third temperature; the third temperature having a value of 5'C or less and the second temperature being selected such that the heat exchange 30 between the bakery product and the filling material(s) results in a filled bakery product having substantially -^463.Alvl 0- c:ober 1999 - 3 the desired third temperature.

Typically, the filling of the bakery product iscarried out at ambient temperature. It will therefore be necessary to allow for the take up of heat from its environment at the filling station by the cooled bakery product when determining the required second temperature to achieve the desired third temperature of the filled product. Such allowances and the calculation of the required second temperature can readily be determined by simple thermal transfer calculations using known techniques. The calculated values for the second temperature can subsequently be verified by simple trial and error tests. However, for simplicity, the present invention will be described hereinafter ignoring the heat taken up by the cooled bakery product from the environment.

The invention can be applied to a wide range of bakery 20 products, for example sliced bread, split baguettes, rolls or bagels, or split cakes. The term bakery product is therefore used herein to denote in general any product which has been made by a baking process and which has been cut or otherwise split or separated into two or more 25 components between which and/or upon the surface of which it is desired to apply one or more fillings or coatings. For convenience, the invention will be described in terms of a loaf of bread which has been sliced into individual slices using conventional techniques, either at -'-,Ie bakery 30 where the loaf is produced or at the location wnere the filling is to take place prior to pre-cooling the slices P2483.Alvl:czober 1999 to the desired second temperature.

Typically, the bread will have been packed in a sealed bag or other container or packaging at the bakery and will have been packed at a temperature of about 30'C to reduce staling of the bread. The slices are removed from such container or packaging by any suitable means and fed to the means by which the slices are transported through the cooling station using any suitable mechanical or other technique. For convenience, the invention will be described hereinafter in terms of the manual removal of slices from a package and their loading onto the conveyor mechanism for transporting the slices through the cooling station.

In the cooling station, the slices of bread are cooled from the temperature, which may be above ambien-L, at which they are delivered from the bakery to the desired second temperature. The value of this second temperature is such that the heat exchange which subsequently takes place between the cooler bread slices and the warmer filling(s) and the filling station environment will result in an overall temperature for the filled sandwich which lies within the desired range for the third temperature. The value of this second temperature will depend upon the nature of the filling and its temperature and the final temperature, the third temperature, required Z"For the filled sandwich. The optimum value for t-e second temperature will also need to accommodate hea-L -,:,a-ins from the environment in the filling station as sta--=-d above.

The optimum theoretical second temperature can feadily be '2483.Alvl:7 Cc-ober 1999 calculated for any given case and verified by simple trial and error tests. Typically, the slices of bread will be cooled to a temperature of f rom - 5'C to + 2'C and we have found that the use of such a value for the second temperature will give a satisfactory final temperature in a wide range of filled sandwiches.

The cooling may be carried out using any suitable technique, for example using a cold air flow over the slices or by cryogenic techniques. However, if the cooling is carried out excessively rapidly and/or by the use of a cooling medium at an excessively low temperature, freeze burning of the bread may occur. We therefore prefer to carry out the cooling using a flow of air over the slices at an air temperature of from -40'C to - 30'C, typically at about - 350C. The use of such a cooling technique can cool slices of bread to a suitable second temperature in the range -5'C to +20C in less than about 2 to 5 minutes.

Whilst cooling of the slices may be carried out with the individual slices carried through the cooling station lying flat upon a conveyor belt, this may limit the rate of cooling which can be achieved, thus requiring an excessively long residence time for each slice within the cooling station. We therefore prefer to carry the individual slices through the cooling station supported in a manner which enables the cooling medium to gain access to substantially all the exposed surfaces of the slice.

Preferably, this is achieved by providing the conveyor mechanism with a plurality of upstanding slatted, P-463 Alvl 07 3czober 1999 6 reticulate, foraminous or other support members aligned substantially parallel to one another at a spacing which accepts a single slice between adjacent supports in the manner of a toast rack. In order to minimise the space occupied by the supports, it is preferred that they are aligned transversely to the line of travel of the conveyor mechanism. Thus, a preferred form of conveyor mechanism comprises a metal slatted or mesh conveyor carrying an axially spaced apart series of upstanding support hoops or arms which define a slice receiving slot between axially adjacent hoops or arms. Alternatively, the hoops or arms can be carried by transverse members which are linked to lateral chains which form the axial supports and drive members for the conveyor. Such forms of conveyor enable the cooling air to flow over the exposed surfaces of the slices of bread carried on the conveyor. If desired, the supports may be formed so that they can be rotated about an axis parallel to and/or normal to the line of travel of the conveyor so that the airflow over the slices carried by the conveyor can be varied.

It is preferred to form the conveyor as a closed loop, for example as a belt or chain carried by a pair of terminal horizontal rollers or shafts as with a conventional belt 25 conveyor, so that the cooling station can be formed as a compact unit. It is also preferred that the supports be collapsible so as to lie substantially parallel to the plane of the conveyor as the supports return to their initial position to receive a feed of slices of bread. 30 The use of such a configuration for the conveyor also enables the cooled slices to be discharged automatically P2483.Alvl Cctober 1999 as the support member travels around the distal support/drive shaft or roller and the support members splay and adopt an inverted orientation to release the slices.

We believe that such a conveyor in combination with a bakery product filling station is novel. The invention therefore also provides an apparatus for use in the method of the invention having a cooling station adapted to feed cooled bakery products to a filling station at which one or more fillings are to be applied to the cooled bakery products, which apparatus comprises a conveyor mechanism for transporting individual items of the bakery product through a cooling station in which a cooling medium is adapted to flow in thermal contact with the exposed surfaces of the items so as to cool them to a desired temperature, the conveyor mechanism being provided with a plurality of item support members extending generally normally to and spaced apart axially along the line of travel of the conveyor through the coolincr station, adjacent pairs of such support members forming therebetween an item receiving zone in which an item is transported through the cooling station and discharged to the filling station at which a filling is appliled to or between the cooled items to form a filled product which is discharged from the filling station at the desired third temperature.

The cooling station is preferably housed in ar, insulated 30 housing to reduce thermal transfer with the environment of the cooling station and to provide an enc':-sure for ?2463.AIv1 -:--ober 1999 directing the flow of cooling medium, preferably cold air, over the exposed surfaces of the bread slices.

The design, construction and operation of the cooling 5 station may be conventional in nature, using known materials, for example stainless steel, and fabrication techniques.

The cooled slices are discharged from the cooling station at the desired second temperature and proceed to the filling station. As indicated above,this discharge is conveniently achieved by the splaying and inversion of the support members of the conveyor which drop the cooled slices onto a chute, conveyor belt or chain or other mechanism which transports the cooled slices to the filling station. In the filling station, one or more fillings, for example butter, meat or fish products and salads, are applied in known manner using known equipment to the cooled bread slices to form a filled sandwich.

Where the bakery product is a sweet product, for example the top and bottom halves of a sponge cake, the filling material may be jam and/or a natural or synthetic cream or chocolate filling. It is also within the scope of the present invention for a chocolate or other coating to be applied over the filled cake as part of the filling operation or subsequently and the term filling is used herein to denote any such coating.

During the filling step, heat is extracted from the 30 f illing/coating, which is usually used a t ambient temperature, by the cooled bakery product. Bv virtue of P-7293.AlVl -ctober 1999 the transfer of heat between the various components, the temperature of the bakery product rises and that of the filling material(s) drops to provide a filled product which has the desired third temperature required to meet the legislation for that product. Since the heat transfer takes place throughout the product, rather than by extraction of heat through exposed external surfaces, the temperature profile within the final product is surprisingly uniform.

The filled sandwich or other bakery product can be packed for storage and sale in the conventional manner using conventional equipment. However, by the use of the precooling step and the transfer of heat within the product 15 as it is made, there is no need to subject the filled product to the cooling step hitherto considered necessary to meet legislation requirements. Since the cooling is carried out on the initial bread slices, temperature sensitive components of the filling are not subjected to 20 excessive or overly rapid cooling. The method of the invention thus reduces the risk of localised chill burning or other damage. Furthermore, since bakery products can in general be chilled more rapidly than many filling materials, the cooling of the bakery products to the 25 desired second temperature can be achieved using techniques which might damage the fillings materials. This reduces the residence time in the cooling station required. This in turn permits the use of a smaller cooling station than would be required to cool the filled 30 product. This enables a more compact construction to be achieved and reduces the overall time taken to produce a K-48 3. Alvl 3ctober 1999 sandwich having the desired final, third, temperature.

DESCRIPTION OF THE DRAWINGS:

To aid understanding of the invention, it will now be described with reference to a preferred embodiment thereof as shown in the accompanying drawings, in which Figure 1 is a diagrammatic block diagram of the cooling and filling stations; and Figure 2 is a diagrammatic vertical cross section through a cooling station for use in the apparatus of Figure 1.

DESCRIPTION OF THE PREFERRED EMBODIMENT:

The apparatus for cooling and filling slices of bread to produce filled sandwiches comprises a station 1 at which incoming bags containing sliced loaves of bread as conventionally produced by a bakery are unpacked and the individual slices A loaded manually onto the conveyor mechanism for transport through the cooling station 2. The cooled slices B are discharged as described below to the filling station 3 where the filled sandwiches C are produced and discharged to a packing station 4 for packing into plastic trays or the like D for discharge to storage and transport to the end consumer.

The cooling station 2 comprises a thermally insulated housing 20 containing a conveyor 21 which carries a plurality of spaced apart slatted or apertured t-ransverse supports 22 which support the slices A -;nd allow substantia'Llv free flow of cold air over the exposed :--'483.Alvl:z=ber 1999 surfaces of the slices. The support members 22are pivotally attached to a flexible chain conveyor or slotted belt conveyor 21, which is carried upon terminal rollers and drive sprockets 23 and 24 to form a closed loop. The slatted support members 22 form between them a series of transverse pockets 25 for receiving and locating slices of bread A. The supports can be configured so as to support individual single slices or can support two, three, four or more slices in side by side transverse arrangement, in the pocket 25 formed between axially sequential support members 22. Preferably, stops or other means (not shown) are provided to limit the pivot of members 22 so that they lie at an angle of about 45 to the vertical as they transport the slices through the housing 20.

As can be seen in Figure 2, the support members 22 splay as the belt 21 passes around the terminal rollers or shafts 23 and 24. This provides a wide open top to the pockets 25 which enables an operator to insert the slices A more readily into the pockets and allows the cooled slices B to drop from the pockets at the discharge, right hand, end of the conveyor and to drop onto a conveyor (not shown) for carrying the cooled slices B into the filling station 3.

The housing 20 is also provided with a fan 26 for blowing air cooled to 35'C by a cooling coil 27 over the conveyor 21 and the slices A carried by it. If desired, the cold -3S 0 air stream may be directed by individual vents, louvres or baffles (not shown) to specific areas and in specific directions along the length of the conveyor 21 to optimise - 'S 3. Alvl Octo'Cer 1999 the cooling of slices A, for example to vary the cooling effect along the length of conveyor 21.

The sandwich filling and packing stations 3,4 are of 5 conventional design, construction and operation.

In operation, an operator feeds individual slices A into the pockets 25 on the conveyor 21. The slices are carried into the housing 20 where they are cooled to about 2'C by the flow of air chilled to -35'C. The cooled slices B are discharged to the filling station 3 where one or more fillings are applied to them and the filled sandwiches C are formed. The fillings are applied at ambient temperature and are cooled in situ within the sandwich by the cooled bread slices B so that the overall temperature of the filled sandwich C is about 4 to 5'C. No external cooling has been applied to the filling, which can therefore be of a temperature sensitive nature.

The filled sandwich C can the be passed to a conventional packing station 4, for example where it is inserted into a plastic tray D and a foil plastic cover applied thereto and heat sealed in position.

P2463.AlV1 -7 October 1999

Claims

CLAIMS:

1. A method for making a bakery product incorporating a filling, which method is characterised in that it comprises:

a. pre-cooling the bakery product at a cooling station from its ambient first temperature to a predetermined second lower temperature; and b. at a filling station applying one or more filling materials to the cooled bakery product to produce a filled bakery product having a predetermined third temperature of 5C or less; the second temperature being selected such that the heat exchange between the bakery product and the filling material(s) results in a filled bakery product having the desired third temperature.

2. A method as claimed in claim 1, characterised in that the bakery product is sliced bread and at least one filling is applied between two slices to form a sandwich.

3. A method as claimed in either of claims 1 or 2, characterised in that the filling operation is carried out at ambient temperature.

4. A method as claimed in any one of the preceding claims, characterised in that the bakery product is cooled to a second temperature of from -50C to +20C.

5. A method as claimed in any one of the preceding claims, characterised in that the cooling of the bakery product is carried out using a stream of air at a temperature of from -400C to -300C.

P2483.Alvl 06 October 2000 ley

6. A method for making a filled sandwich, which comprises cooling slices of bread to a temperature of from -50C to +20C by means of an air flow at from -400C to -300C and thereafter applying at least one filling to the cooled slices at a filling station operated at ambient temperature.

7. A method as claimed in any one of the preceding claims, characterised in that the bakery products are supported between upstanding support members aligned generally transversely with respect to the line of travel of a conveyor mechanism by which they are transported through the cooling station.

8. A method as claimed in claim 7, characterised in that the support members are carried by a conveyor which travel around a closed loop path.

9. A method as claimed in claim 8, characterised in that the bakery products are discharged from the support members by splaying of the support members as the conveyor mechanism traverses a bend in its travel.

10. A method as claimed in any one of the preceding claims, characterised in that the filled bakery product is packaged for storage and transport without further cooling of the filled product.

11. A method according to claim 1 substantially as hereinbefore described with respect to the accompanying drawings.

12. An apparatus for use in the method of claim 1, having a cooling station adapted to feed cooled bakery products to a filling station at which one or more fillings are to be applied to the cooled bakery P2483.Alvl 06 October 2000 products, which apparatus comprises a conveyor mechanism for transporting individual items of the bakery product through a cooling station in which a cooling medium is adapted to flow in thermal contact with the exposed surfaces of the items so as to cool them to a desired temperature, the conveyor mechanism being provided with a plurality of item support members extending generally normally to and spaced apart axially along the line of travel of the conveyor through the cooling station, adjacent pairs of such support members forming therebetween an item receiving zone in which an item is transported through the cooling station and discharged to the filling station at which a filling is applied to or between the cooled items to form a filled product which is discharged from the filling station at the desired third temperature.

13. Apparatus as claimed in claim 12, characterised in that the cooling station is housed in an insulated housing to reduce ther mal transfer with the environment of the cooling station, which housing provides an enclosure for directing the flow of cooling medium over the exposed surfaces of the bakery products.

14. Apparatus as claimed in either of claims 12 or 13, characterised in that the conveyor mechanism is a metal mesh or slat conveyor belt.

15. Apparatus as claimed in claim 12, substantially as hereinhefore described with respect to and as shown in any one of the accompanying drawings.

P2483.Alvl 09- Cctober 2000