This invention relates to a method for preparation of a bakery product with double filling, where one of the two fillings encloses the other filling in a way that the later filling is completely isolated from the bakery product; also the apparatus for injection of this double filling in bakery products before or after baking.

A bakery product with double filling, where one of the fillings encloses the other filling, is a technological achievement, due to the innovative way introduced in order to improve the keeping qualities (appearance and taste) of filled bakery products.

Filled bakery products make up a popular category of bakery products. Fillings are incorporated in the bakery products before or after the baking process.

Filling before baking is possible in bakery products that have started from dough (that are not liquid).

After dough mixing, the dough and filling can be configured by co-extrusion so as the dough part is incorporating into the filling. Patent US 6443055 describes a similar method and apparatus.

As an alternative, a dough slab can be formed and the filling can be deposited onto it. Then the dough is folded in such a way that makes it possible to incorporate the filling. Patent EP 2149304 describes a similar method.

A disadvantage of the methods mentioned above may be that the filling is thermally abused due to the high temperatures prevailing during the baking process. Furthermore, these methods cannot be applied in bakery products that are starting from a batter (that is liquid dough) such as cakes, wafers and other.

When bakery products start from batters, then the fillings can be introduced after baking by injection.

As an alternative, some bakery products like wafers can be formed in two concave pieces and the filling can be deposited into them; then the two concave pieces are glued together so as to enclose the filling.

Patent EP 1388287 describes another way to get a filled product starting from a batter; Batter is partially baked in order to get suitable structure, so that the filling can be deposited onto it; after a folding step, baking is finalized by passing the filled product in a second oven. Injection of fillings after baking is also a quite popular method.

This method applies to bakery products that start from batters, where introduction of the filling before baking is not possible. Additionally, this is a general method of filling bakery products, when the type of filling is such that it is not possible, nor desired to impose the filling to thermal abuse of baking.

The filling is injected as a semi-liquid in the baked product via a special filling head shaped as syringe. Patent US 2664054 describes apparatus for this method. Injection of the filling commences soon after baking, so bakery products are flexible enough to accept the filling.

Two or more fillings can be incorporated in bakery products by any of the methods mentioned above.

The principle of enclosing a filling with another filling can also be applied to bakery products by existing methods.

Patent US 6443055 describes a general method, where a "filling" can be enclosed in a

"casing"; that is a moldable food component like dough or another filling.

According to this method two components (for convenience called "filling" and

"casing") are fed in two hoppers equipped with screw conveyors and then co-extruded through a double nozzle. Two pumps are proportionally dosing the components through the double nozzle, and then a cutting mechanism is cutting the otherwise continuous entity in pieces, so that the "filling" is enclosed in the "casing".

Both components ("filling" and "casing") need to be moldable. It is obvious that this method cannot be applied in pre-shaped products before or after the baking process, where the "casing" is a pre-shaped dough piece.

The later method can also be applied for the preparation of the double filling, where one encloses the other; then this double filling can be deposited on a dough slab, and then the dough folds to enclose the double filling. After the baking process, the bakery product encloses the double filling that encloses the other. It is obvious that this method cannot be utilized for pre-shaped bakery products either before or after baking. A double filling where one of the fillings encloses the other, so that the later filling is isolated from the bakery product is an interesting taste perspective, but also a technical solution for products, where there are undesired interactions between filling and baked product, which unacceptably compromise shelf life, so that the product cannot be merchantable.

In some cases, the filling is too liquid and is absorbed by the baked dough during time, so it loses its discrete presence in the filled bakery product.

In other cases, there is unacceptable migration of moisture, flavors and other volatile and non volatile compounds that compromise the keeping quality of the filled bakery product.

As a solution, a second outer filling with suitable properties can be chosen to act as protective casing to the inner filling and improve the keeping qualities of the filled bakery product.

It is asked that this double filling can be incorporated in bakery products after the baking process, so the products that are starting from batters can be filled. It is also asked that these fillings will not be imposed to the temperature abuse of the baking process. It is finally asked that this method applies to bakery products before or after baking without shape or other restrictions.

This invention describes a method and apparatus, where two fillings are injected simultaneously in the bakery product before or after baking without undesirable intermixing and in a way that the outer filling encloses completely the inner filling, so that the inner filling is by no means in contact with the bakery product.

This particular method allows the injection of this double filling (where one filling encloses the other filling) before baking in pre-shaped dough. This means that the dough will have received its characteristic shape before filling.

This method makes it possible to inject a filling to a bakery product starting from batter, after having reached a desirable structure through baking.

Filling a bakery product after baking can be possible with this method, only if it is flexible enough, in order to be filled by injection.

The configuration of a filled bakery product of arbitrary shape after the incorporation of this double filling, where one of the fillings encloses the other filling, so that the later is not in contact with the bakery product, appears in fig. 1 (cross section and side view). The method of penetration and injection of this double filling explained below and the presented apparatus applies for the incorporation of the double filling inside the bakery product after but also before the baking process.

Fillings are injected simultaneously, while the injection head is moving inside the baked product or dough.

As shown in fig. 2 (side view and cross section), the injection head consists of two concentric narrow tubes, through where the two fillings are injected. The inner filling runs through the inner tube, whereas the outer filling follows the periphery formed between the two concentric narrow tubes.

Dimensioning of the concentric narrow tubes takes into account the amount of fillings and their ratio in the final product, in order that the fillings get similar linear velocities during dosing to avoid intermixing. The above has to be achieved with a minimum outside diameter of the external tube, for ease of penetration without damaging the baked product.

Injection nozzle tip is narrow, in order to assist the penetration of the bakery product. As this can cause intermixing of the creams during passage, the internal tube is shorter. In this way, the double filling is ejected without mixing, as an entity, through the nozzle tip.

The fillings are fed though the injection nozzle seat (fig. 2 - cross section), which distributes the inner filling through the inner narrow tube and the outer filling to the periphery that is formed between the two concentric narrow tubes.

A simplified version of the apparatus for the injection of this double filling is shown in fig. 3 and 4. For ease of understanding all movements, are described by their pneumatic analogs. This apparatus can fill one product at a time.

A higher level of precision and speed can be achieved by using more sophisticated electromechanical and electronic parts (step motors, PLC's). Moreover, this apparatus can be extended to fill up many products simultaneously.

All parts of the apparatus are seating on base plate (1) shown in fig. 3.

The bakery product for filling is introduced in guide (2) and is standing secure by a compressing piston (3). The base plate (12) can move horizontally (fig. 4) sliding freely over slide (17) positioned over piston (18). Base plate (12) supports the injection head and the hoppers of the two fillings.

The base plate (12) takes three characteristic end positions, while moving. These end positions are dictated by the relative positions of photocells (20), which, by their turn, are monitoring the position of the base plate through pointer (19).

The far right position (fig. 4) is the zero position of the filling mechanism. The far left

(20) is the position of maximum penetration inside the product and beginning of injection. The middle position (20) is the position, where injection ends.

The speed of movement of the base plate (12) during penetration, but also injection, can be regulated by adjusting the air supply over piston (18).

The two fillings are fed in hoppers (4) and (5) respectively. Dosing cylinders (21) are filled by suction and injected by compression arising from pistons (10) and (11).

A special three-way valve (6) is located beneath hoppers (4) and (5) and has two end positions according to position of arm (7), which, by its turn, is moving from piston (8) that is fastened on its other end on the base plate (9).

The special configuration of the three-way valve (6) allows for the simultaneous suction of the two fillings from the respective hoppers, when dosing cylinders are in suction step and the simultaneous injection of the two fillings, when the dosing cylinders (21) are in compression step.

End positions of the pistons (10) and (11) determine the amount (volume) of the fillings, which, by their turn, are defined by the relative positions of photocells (14), which are monitoring the movement of pointers (13).

During injection, both fillings are fed through injection nozzle seat (15) and passing through injection nozzle (16), which, by its turn, is moving inside the bakery product, in order to distribute the double filling across its path.

In order to achieve a complete isolation of the inner filling a lead time, at the beginning, and a lag time, at the end of injection of the outer filling, are set, by timing the relative movements of the dosing cylinders. By this way but also due to the special shape of the injection nozzle, only the outer filling is dosed at the beginning and at the end of the injection, sealing in this way the inner filling. The apparatus for the injection of the double filling, as presented, makes possible the incorporation of this double filling inside the bakery products of varying shapes. It is a prerequisite of this method that bakery products are in flexible state, in order to allow penetration from the injection head and yield enough, in order to incorporate the new volume introduced by the fillings, without rupture of their continuous structure.

The special configuration of the injection nozzle allows for the incorporation of the double filling, without intermixing of the two fillings, but also minimize the damage and deformation of the bakery product.

Finally, the movement of the injection head, while injecting, allows a uniform distribution of the double filling across the path of the injection head. Due to this, consumers can enjoy both fillings as discrete entities throughout the body of the filled bakery product.

This particular method also provides with the apparatus, presented above, which makes the incorporation of this double filling in bakery products, before or after the baking process. This double filling, by its turn, makes possible the utilization of fillings that otherwise would be not possible to be kept inside bakery products, in order to be merchantable.

As an example, water based fillings of low viscosity (like honey) tend to be absorbed and soak bakery products. A second filling (for example fat based) could be used as an outer filling to enclose the first filling and by this way isolate it from the bakery product.

As another example, no moisture containing fillings (like confectionery spreads) tend to dry bakery products, due to high water activity difference. A filling of suitable water activity could be used as an outer filling, in order to minimize the migration of moisture from the bakery product to the filling.