Field of the Invention

The present invention refers to everyday-life needs, and among them, to the field of food product manufacturing processes.

More particularly, it describes a process for producing a pasty food product comprising a series of steps wherein a batch of components at low relative humidity are repeatedly processed using colloid mills through cycles in which the temperature is gradually raised until the material reaches an adequate pasty consistency.

The invention also refers to a device that can be used in said process, which different embodiments provide for either repeated recirculation through a colloid mill or circulation of the mixture through multiple cycle stations.

Background

Different industrial processes are known in the art of manufacturing pasty food products.

For example, in the case of "dulce de leche" (also known as milk jam or milk caramel) the best known process is one carried out in a pan. In general, it is an indirect cooking method using a jacketed pan evaporator through which flows a hot vapor stream. Fluid milk and sugar are poured into the pan, with the addition of sodium bicarbonate and some glucose syrup. All these ingredients are continuously stirred while the mixture is cooked until it caramelizes and concentrates into the desired viscosity and quality.

It should be remarked that the starting material is a substantially liquid mixture which, after several steps, is gradually thickened into a pasty mixture that may have different levels of humidity. For example: the product used by confectioners and "alfajor" manufacturers has a humidity value of approximately 23%, while milk- jam spreads used in the home usually have a humidity of approximately 27%.

These conventional methods, depending on the available equipment, usually take several hours since the initial humidity values are high - approximately 60% depending on the formula - and the concentration rate is low to avoid excessive carbonization caused by high temperatures. Another known process consists in replacing fluid milk by previously concentrated milk which, although implying a double process, reduces the initial humidity values and shortens cooking times.

In spite of this difference, it is a process dealing with an essentially humid matter, and designed to reduce such high humidity along different stages to obtain a more viscous final product.

Generally, the prior art processes are continuous processes in which a substantially liquid mix is gradually modified into a thicker or more pasty product.

Advantages and purposes of the invention

A first difference between the present process and the prior art is that the present process is a batch process or continuous production, that is to say, that each step of the process is applied to a whole batch of the mixture.

Another difference is that this process develops in the contrary sense to the known methods, since the latter methods start from a liquid or high humidity mixture that is thickened by loss of humidity. On the contrary, the process of the invention begins with a mixture with very low relative humidity and is gradually heated to reach the required temperature and the final product is then obtained by the addition of the necessary water/liquid to reach the desired viscosity.

An advantage of this process is its very low power consumption, which positively affects the costs of the final product. In addition, the invention uses less equipment and less inputs such as steam.

Another advantage of the invention is that it implies a substantial simplification in the number and types of steps necessary to obtain an important production volume. This process does not involve evaporation of fluid because of the high concentration of solids and the control of the maximum desired temperature.

A further advantage of the process of the invention is that the desired density or viscosity is achieved by the addition of liquid, which makes it easier to obtain pasty food products with different final concentrations. Such is the case of "dulce de leche" which can then be produced in different densities, ranging from high density to low density watery products.

An additional advantage of the invention is that it is possible to use devices with different configurations. In fact, suitable equipment may consist of either recirculating devices based on a single colloid mill or multiple cycle stations integrating a continuous arrangement. A further additional advantage of the invention is that it uses extremely simple devices and the process can be easily and fully controlled along all its steps.

A still further advantage of the invention is that it does not require direct-heating equipment or fluid inputs such as steam, because temperature is handled by flow pressure control in combination with grinding pressure and/or valve means.

Ill - Brief description of the Figures

The following drawings have been included for illustration and clarity purposes. The drawings represent the preferred embodiments of the invention and are not limiting.

Figure 1 is a side elevation view of the single device used in the process of the present invention.

Figure 2 is a partial longitudinal section that shows the arrangement of the different components of the colloid mill.

Figure 3 is a side elevation view of an embodiment of the device in which, in addition to the initial colloid mill, seven cycle stations have been included.

Figure 4 is a side elevation view of the device used in an embodiment of the invention in which, in addition to the initial colloid mill, three cycle stations have been included.

List of references:

(I) Colloid mill.

(10) Feeding vessel.

(I I) Feeding vessel cavity(10).

(12) Screw conveyor.

(12a) Conveyor duct.

(13) Mill Stator (1).

(13a) Stator.

(13b) Grinding gap regulator [grinding gap (13a)(14a)].

(14) Mill rotor (1).

(14a) Rotor bit.

(15) Mill motor (1).

(16) Motor drive axle (15).

(17) Feed agitator.

(18) Feed agitator blades.

(19) Mill discharge port( 1 ) . (2) Intermediate vessel .

(20) Intermediate vessel walls (2).

(21) Intermediate cavity of the intermediate vessel (2).

(22) Recirculation duct.

(23) Recirculation valve means.

(24) Intermediate agitator.

(25) Intermediate agitator blades.

(3) Circulation duct.

(31) Valve means for flow pressure control.

(32) Recirculation duct.

(33) Circulation duct.

(34) Temperature gauge.

(35) Two-way valve means.

(36) Discharge duct.

(50) Mixture batch.

(100 Cycle stations.

(101 First cycle station.

(102 Second cycle station.

(103 Third cycle station.

(104 Fourth cycle station.

(105 Fifth cycle station.

(106 Sixth cycle station.

(107 Seventh cycle station.

IV - DESCRIPTION

In general, the present invention is directed to a process for producing a pasty food product comprising multiple steps for processing a mixture batch (50) at very low relative humidity - less than 20% -. During the process, the mixture passes several times through a single colloid mill (1) or circulates through multiple cycle stations (100) connected by ducts (32)(33) under flow pressure control (31). In the final steps of the process, the process comprises the addition of the necessary liquid to achieve the desired density of the mixture batch (50). The process device may comprise a single colloid mill (1) adapted for recirculation, or it may include multiple cycle stations (100) equipped with additional colloid mills (1).

Detailed Description of the Invention A) Process

More particularly, the present process for preparing pasty food products comprises a first step wherein the ingredients of the food product are mixed to obtain a low relative humidity mixture.

For example, if the food product is a milk jam, the ingredients are selected from a group comprising powdered milk, sugar, glucose and bicarbonate, with the addition of a liquid— typically water— to obtain the desired low relative humidity which is preferably below 20%, for example, 10%. The initial temperature of the mixture batch may be for example 30°C, with a ±15% tolerance.

Once the initial mixture has been obtained, a batch (50) is placed in the cavity of the feeding vessel (10) of colloid mill (1) and the screw conveyor (12) moves it into the position in which the mixture (50) is ground by the grinding bits (13a)(14a) of the stator (13) and the rotor (14). During this step, a regulator (13b) may control the gap between the grinding bits (13a)(14a) of the stator (13) and the rotor (14).

Then, the mixture batch (50) goes through a circulation duct (33) equipped with flow pressure control, from the mill's discharge port (19) towards an intermediate vessel (2)capable of holding the whole batch (50).

In an embodiment of the invention, only one colloid mill (1) is used, and once said mixture batch (50) has completed the process cycle in the colloid mill (1) and the intermediate vessel (2), it is recirculated into the feeding vessel (10) of the mill (1). This cycle is repeated a plurality of times and, the temperature of the mixture batch (50) increases gradually in each cycle.

Once a final mixture temperature above 100°C is reached, the final mixture is obtained by the addition and stirring of liquid to obtain a pasty food product with the desired consistency.

In another embodiment of the invention, an initial colloid mill (1) and a plurality of cycle stations (100) are used, each of them (101)( 102)( 103)( 104)( 105)( 106)(107) comprising a colloid mill (1), a circulation duct (33), flow pressure control means (31) an intermediate vessel (2) and a circulation passage (3).

Once the mixture batch (50) has gone through the initial colloid mill (1), it passes through a circulation duct (33) having pressure control means (31) from the discharge port (19) of said initial mill (1) towards the first available intermediate vessel (2) of a first cycle station (101) which is capable of containing the whole mixture batch (50). Once the mixture batch (50) has completed the process cycle at the first cycle station (101) - comprised by a first colloid mill (1), and a first intermediate vessel (2)- , it moves to the feeding vessel (10) of a second cycle station (102).

Subsequently, the process comprises as many process cycles as cycle stations (100) present in the device, performing one cycle at each station, and gradually raising the temperature of the mixture batch (50) in each cycle.

Also in this embodiment, when a final temperature above 100°C is reached, the final product is obtained by the addition and mixing of liquid to provide a pasty food product with the desired consistency.

Additional process steps may be added upon completion of the above described process cycles. For example, a step comprising the addition of liquid to the mixture batch (50), and mixing [for example by stirring] to reach the desired consistency. Another additional cycle could comprise homogenizing the batch.

B) Device:

In one embodiment, the device comprises a colloid mill (l)including a feeding vessel (10). Such feeding vessel (10) ends in a passage (12a) within which a screw conveyor (12) drives the mixture batch (50) into the grinding section. The grinding section includes a stator (13) and a rotor (14) of the mill (1) in which the corresponding grinding bits (13a)(14a) operate on the mixture batch (50), as it passes therebetween (13a)(14a). A regulator (13b) can be used to adjust the clearance between the grinding bits (13a)(14a) as a control means to modify the temperature of said mixture (50). All moving parts (12)(14) are driven by the motor(15) of the mill (1).

The discharge port (19) of said mill (1) communicates with a circulation duct (33), from said colloid mill (1) towards an intermediate vessel (2). Said circulation duct (33) can be fitted with flow pressure control means (31) of the mixture (50), which also allow to control the temperature of said mixture (50). Temperature gauge means (34) for the circulating mixture (50) can also be included.

The intermediate vessel (2) at the end of the circulation duct (33) is adapted to hold a full batch of the mixture (50). The intermediate vessel (2) discharges into a recirculation duct (22) fitted with recirculation valve means (23) which control the discharge rate of the colloid mill (1).

This device is capable of performing several process cycles of a mixture batch (50) which is discharged from the device once the process has been completed. For said purpose, a two-way valve means (35) can be used, communicating the discharge port (19) of the mill (1), either with the recirculation duct (32) or with the discharge port duct (36).

The mill (1) can be fitted with a feed agitator (17) which blades (18) operate within the cavity (11) of the feeding vessel (10). An additional intermediate agitator (24) can be used which blades (25)operate within the cavity(21) of the intermediate vessel (2).

In another embodiment, the device comprises, in addition to the initial mill (1), multiple cycle stations (100).

Each cycle station comprises a colloid mill (1), a circulation duct (33), flow pressure control means (31), an intermediate vessel (2) and a recirculation duct (22) for the mixture batch (50). In this arrangement, each circulation duct (33) connects the respective colloid mill (1) of one cycle station (100), with the intermediate vessel (2) of the next cycle station (100), in the machine direction of the mixture batch (50).

C) Examples

The following examples describe some embodiments of the process of the invention:

Example 1 :

This example shows the temperatures to be controlled during a process using any of the devices of the invention.

Cycle Temperature [±15%]

Initial (before lsr Cycle) 30°C

First cycle 50°C

Second cycle 65°C

Third cycle 80°C

Fourth cycle 95°C

Fifth cycle 105°C

Sixth cycle 115°C

Example 2:

This example shows other temperatures to be controlled during a process using any of the devices of the invention.

Cycle Temperature [±15%]

Initial (before 1 st Cycle) 30°C First cycle 50°C

Second cycle 65°C

Third cycle 80°C

Fourth cycle 95°C

Fifth cycle 105°C

Sixth cycle 115°C

Seventh cycle (addition of liquid) 1 15°C

Eighth cycle (homogenization) 1 15°C

Example 3 :

This example shows other temperatures to be controlled during a process using any of the devices of the invention.

Cycle Temperature [±15%]

Initial (before 1 st Cycle) 30°C

First cycle 40°C

Second cycle 50°C

Third cycle 60°C

Fourth cycle 70°C

Fifth cycle 80°C

Sixth cycle 90°C

Seventh cycle 100°C

Eighth cycle 115°C

Example 4:

This example shows other temperatures to be controlled during a process using any of the devices of the invention.

Cycle Temperature [±15%]

Initial (before 1 st Cycle) 30°C

First cycle 60°C

Second cycle 80°C

Third cycle 95°C

Fourth cycle 115°C

Example 5:

This example shows other temperatures to be controlled during a process using any of the devices of the invention.

Cycle Temperature [±15%] Initial (before 1 st Cycle) 30°C

First cycle 60°C

Second cycle 80°C

Third cycle 95°C

Fourth cycle 1 15°C

Fifth cycle (addition of liquid) 115°C

Sixth cycle (homogenization) 1 15°C

Example 6:

This example shows the temperatures to be controlled during a process using the device comprising only one mill (1):

Recirculation Cycle Temperature [±15%]

— Initial (before 1 st Cycle) 30°C

— First cycle 50°C

Firsta Second cycle 65°C

Segunda Third cycle 80°C

Tercera Fourth cycle 95°C

Cuarta Fifth cycle 105°C

Quinta Sixth cycle 115°C

Example 7:

This example shows other temperatures to be controlled during a process using a device comprising multiple cycle stations (100).

Station Cycle Temperature [±15 %]

— Initial (before 1st Cycle) 30°C

Initial mill (1) First cycle 50°C

Firrst station (101) Second cycle 65°C

Second station (102) Third cycle 80°C

Third station (103) Fourth cycle 95°C

Fourth station ( 104) Fifth cycle 105°C

Fifth station ( 105) Sixth cycle 115°C

Sixth station (106) Seventh cycle (addition of liquid) 115°C

Seventh station (107) Eighth cycle (homogenization) 115°C

It will be evident for those skilled in the art that when putting into practice the present invention different modifications may be introduced regarding certain aspects and forms of the different embodiments, without departing from the essential principles of the invention, which are clearly defined in the following claims.