GB1583182A - Bread making - Google Patents

Description

(54) BREAD MAKING (71) We, SERGE LEFEUVRE, a French citizen, of 2 rue Charles Camichel, 31 071 Toulouse, France, ROGER REMY, a French citizen of 61 rue de la Paix, 94 Le Perreux, France, and RENE MAURICE SICHET, a French citizen, of 5 Avenue du Pasteur Martin Luther King, 78 190 Trappes, France, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: This invention relates to bread making.

An object of the invention is to improve the customary process of panification and more particularly to reduce the baking time, increasing productivity accordingly.

The invention provides a method of making bread wherein a basket containing a plurality of pre-formed loaves is placed in an oven wherein conventional baking by the application of external heat is supplemented by the application of micro-wave heating which commences simultaneously with the application of external heat, and wherein the microwave heating is terminated before the conventional heating.

The invention will be described further by way of example, with reference to the accompanying drawings, wherein: - Figure 1 is a schematic elevational view of a micro-wave oven, suitable for the prebaking of loaves of about 750 grammes; and Figure 2 is a schematic plan view of the oven of Figure 1.

The method of the invention combines the usual panification process with a simultaneous additional cooking step initiated simultaneously with the conventional baking by use of micro-waves.

An oven for this method is essentially constituted by a close and parallelepipedic metal enclosure 1, comprising at least one mobile wall, in order to be able to centre therein, in the zone shown cross-hatched. a basket 2, (of the type currently used in a bakery, and containing a plurality of previously prepared dough shaped into loaves) wherein the loaves, in addition to the application of conventional (e.g. infra-red) heating simultaneously subjected to an initial brief micro-wave cooking step, for example of a duration of the order of a minute).

After this the partly-baked loaves are finished by conventional heating. The micro-wave heating is effected by means of a magnetron generator having a stabilised electrical feed. The micro-waves are guided and retained by successive reflections against the internal walls of a U-shaped wave guide 4, above the upper wall of the oven 1 and are distributed uniformly in the oven through slots 5 dimensioned and mutually spaced apart to foster the establishment of a stationary wave pattern, in the direction of the arrow f and thus a good homogeneity of the power dissipated, in a plane perpendicular to this direction.

In the case of a magnetron 3, generating micro-waves of a frequency of 2,450 MHz, the rectangular internal section of the wave guide 4 will advantageously be 8.636 x 4.318 centimetres.

For loaves of about 750 grammes - disposed in a conventional basket such as 2, excellent results have been obtained with micro-wave heating for a period of the order of one minute, in a metallic enclosure forming an oven 1 of 94 x 76 x 31 centimetres and using a magnetron of a useful power of the order of 5 kilowatts and the arrangement of the wave guide 4 schematically shown in Figures 1 and 2, with slits such as 5 mutually spaced apart by 17.4 centimetres, from axis to axis.

The slits are mutually spaced apart by one wave-length, or a multiple thereof. They are electrically in the same state, for example in parallel, and their dimensions, their spacing from the axis of the guide and the position of the terminal short-circuit are calculated and adjusted experimentally, as a function of the mean electrical characteristics of the dough, so that each slit is "at resonance", while presenting a stationary wave relation which is as low as possible.

In the experimental conditions thus described and illustrated by Figures 1 and 2 and for the aforesaid particular case of the baking of loaves of about 750 grammes, excellent results have been obtained with a very brief micro-wave heating, of the order of one minute, followed by a further thermal, e.g. infra-red, baking of the order of 10 minutes, thus reducing considerably (by more than half) conventional baking times, therefore increasing productivity while ensuring a better baking at the centre of the loaves, Better results are obtained by substituting infra-red electrical heating for conventional hot-air heating for further baking.

The method of panification thus described, for the particular case of application to loaves of 750 grammes are applicable to other types of loaves.

The invention is not limited to the precise details of the foregoing and variations can be made thereto.

WHAT WE CLAIM IS: 1. A method of making bread wherein a basket containing a plurality of pre-formed loaves is placed in an oven wherein conventional baking by the application of external heat is supplemented by the application of micro-wave heating which commences simultaneously with the application of external heat, and wherein the microwave heating is terminated before the conventional heating.

2. A method as claimed in claim 1, wherein conventional baking is effected by infra-red heating.

3. A method as claimed in claim 1 or 2 wherein micro-wave heating and conventional baking are effected in a tunnel oven.

4. A method of making bread as claimed in any of claims 1 to 3 and substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.

5. Apparatus for making bread, when used for carrying out the method of any preceding claim and comprising an oven having a baking heater for applying external heat to a loaf, and a micro-wave heater.

6. Apparatus as claimed in claim 5, wherein a generator of the micro-wave heater is a magnetron. having a power of the order of 5 kilowatts at a frequency of 2,450 MHz and a wave guide of internal rectangular section of 8.636 x 4.318 centimetres fixed to an upper wall of the oven and comprising equi-distant slits spaced apart by the wave length or by a multiple of the wavelength of the aforesaid micro-waves, opening out into the oven and positioned so as to foster therein the establishment of a stationary wave pattern and presenting a .wave ratio which is as low as possible.

7. Apparatus as claimed in claim 5 or 6 wherein the baking heater is an infra-red heater.

8. Apparatus as claimed in claim 5, 6 or 7 wherein micro-wave heater and baking heater are arranged in a tunnel oven.

9. Apparatus for baking bread when used for carrying out the mthod of any of claims 1 to 4 and substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (9)

**WARNING** start of CLMS field may overlap end of DESC **. from the axis of the guide and the position of the terminal short-circuit are calculated and adjusted experimentally, as a function of the mean electrical characteristics of the dough, so that each slit is "at resonance", while presenting a stationary wave relation which is as low as possible. In the experimental conditions thus described and illustrated by Figures 1 and 2 and for the aforesaid particular case of the baking of loaves of about 750 grammes, excellent results have been obtained with a very brief micro-wave heating, of the order of one minute, followed by a further thermal, e.g. infra-red, baking of the order of 10 minutes, thus reducing considerably (by more than half) conventional baking times, therefore increasing productivity while ensuring a better baking at the centre of the loaves, Better results are obtained by substituting infra-red electrical heating for conventional hot-air heating for further baking. The method of panification thus described, for the particular case of application to loaves of 750 grammes are applicable to other types of loaves. The invention is not limited to the precise details of the foregoing and variations can be made thereto. WHAT WE CLAIM IS:

1. A method of making bread wherein a basket containing a plurality of pre-formed loaves is placed in an oven wherein conventional baking by the application of external heat is supplemented by the application of micro-wave heating which commences simultaneously with the application of external heat, and wherein the microwave heating is terminated before the conventional heating.

2. A method as claimed in claim 1, wherein conventional baking is effected by infra-red heating.

3. A method as claimed in claim 1 or 2 wherein micro-wave heating and conventional baking are effected in a tunnel oven.

4. A method of making bread as claimed in any of claims 1 to 3 and substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.

5. Apparatus for making bread, when used for carrying out the method of any preceding claim and comprising an oven having a baking heater for applying external heat to a loaf, and a micro-wave heater.

6. Apparatus as claimed in claim 5, wherein a generator of the micro-wave heater is a magnetron. having a power of the order of 5 kilowatts at a frequency of 2,450 MHz and a wave guide of internal rectangular section of 8.636 x 4.318 centimetres fixed to an upper wall of the oven and comprising equi-distant slits spaced apart by the wave length or by a multiple of the wavelength of the aforesaid micro-waves, opening out into the oven and positioned so as to foster therein the establishment of a stationary wave pattern and presenting a .wave ratio which is as low as possible.

7. Apparatus as claimed in claim 5 or 6 wherein the baking heater is an infra-red heater.

8. Apparatus as claimed in claim 5, 6 or 7 wherein micro-wave heater and baking heater are arranged in a tunnel oven.

9. Apparatus for baking bread when used for carrying out the mthod of any of claims 1 to 4 and substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.