IT201600127410A1 - DEVICE FOR THE REALIZATION OF A MICROBIOLOGICAL ABATEMENT TREATMENT OF LIQUID FOOD PRODUCTS - Google Patents

Description

Title

DEVICE FOR THE REALIZATION OF A MICROBIOLOGICAL ABATEMENT TREATMENT OF LIQUID FOOD PRODUCTS

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DEVICE FOR THE REALIZATION OF A MICROBIOLOGICAL ABATEMENT TREATMENT OF LIQUID FOOD PRODUCTS.

Applicant: DI CARLO FRANCESCA.

Designated inventor: Francesca Di Carlo.

The present invention relates to a device for carrying out a microbiological abatement treatment of liquid food products.

The invention in question is advantageously applied in the dairy sector and / or liquid egg products and the like, to which the following description will make explicit reference without thereby losing generality.

In general, the continuous demand for food products characterized by nutritional, sensory and organoleptic properties similar to those of fresh products, has prompted the food industries to use non-thermal or thermobonding preservation technologies, such as food preservation technology. through the use of PEF technology (Plused Electric Fields) which

consists in the application of pulsed electric fields, obtained from a high voltage source of pulsations.

It is mainly a cold microbiological remediation technology

of products with a high protein content such as milk and derivatives and liquid eggs.

The destruction of the microorganisms inside the food placed between two electrodes achieved with the application of short high voltage pulses (20-80 Kv) is such as to cause the rupture of the membranes of the microbial cells (electroporation), with modest increases thermal.

According to this technology, when the trans-membrane potential exceeds a value

critical (1 volt) electrical collapse of the membrane occurs, local change

of the membrane conformation, an increase in permeability and loss of

cellular components. When the critical potential is exceeded, charges are formed with

opposite sign on the two sides of the membrane, with compression of the same e

formation of pores. The size of the pores depends on the strength of the electric field

and the number of electrical pulses. If the total pore area exceeds a certain

percentage, the latter breaks irreversibly, otherwise the pores can

close and the cell, even if damaged, can survive the treatments.

As far as most liquid food fluids are concerned, these are possible

distinguish relative to their own electrical characteristics including high

conductor and insulator. In a conductor the electrical charges are free to move

freely in response to an external electric field, resulting in a flux of

current, which leads the electrical charges of the conductor to restore equilibrium

internal electrical, while an insulator characterized by fixed charges prevents the

passage of current. '

Liquid food fluids generally have intermediate characteristics but sometimes

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also very different from each other and therefore can be characterized through the

their conductivity or the ability to transport electrical charges.

As an example, it is sufficient to consider that in the liquid egg product industry,

the egg white which contains on average 89% of water has a conductivity equal to 9.2

mS / cm, while the yolk with an average dry residue equal to 43% has a conductivity

equal to 4.0 mS / cm, or less than half.

This peculiarity is also found in the dairy industry among products such as milk,

cream, yogurt etc.

The factors that influence microbial inactivation with the use of PEFs are

the intensity of the applied electric field, type of pulses, treatment time e

temperature. The first factor, namely the strength intensity of the applied electric field,

is indicated as the most important factor (Qin et al 1998) and is represented by

symbol V, generated by the potential difference applied between the two electrodes on a

material of thickness d and for which the formula of the electric field E holds:

E = VI d (Wm).

According to this formula, the electric field that is created is therefore directly

proportional to the potential difference and inversely to the distance at which this

It is applied. By increasing the gap between the electrodes, to achieve the same intensity it is

it is necessary to increase the voltage or the potential difference (Zhang et al

1994).

In electroporation, this is exactly what happens, all other conditions being equal

such as the dielectric constant defined as the physical quantity that

quantifies the propensity of a substance to counteract the intensity of the field

electric field inside it, and an electric field <*> is created directly

dependent on the distance of the electrodes.

A reliable and effective PEF treatment for highly microbial inactivation

dependent on the uniform intensity of the electric field in the treatment area of the

camera (Fiala et al, 2001). Non-uniform electric fields lead to two problems

main: in the first place on the occurrence of high intensity peaks causing a

potential sudden temperature rise, the second big problem

erosion of electrodes and insulators due to the formation of arcs

(Schroeder, Buckow, Knoerzer). The first treatment chambers used to such

scope included parallel plates comprising a pair of planar electrodes.

This arrangement provides a uniform distribution of the electric field.

However, the geometry of the conventional parallel plate treatment chamber

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causes edge effects caused by the fact that the electric field tends to be of

greater intensity at the edges of the electrodes than at the center of the electrodes.

Furthermore, this localized intensity can lead to the formation of arc discharges

through the fluid liquid to be treated which can adversely affect the

nutritional and organoleptic characteristics of the fluid itself.

To overcome these drawbacks, the use of chambers has spread over time

coaxial treatment in which an internal electrode having a cylindrical shape is placed at the

center of the external electrode having an annular shape.

The fixed electrode spacing can be varied by varying the diameter of one of the

two electrodes obtaining different distances (gaps) between the two.

As known art, Bushnell document US 5048404 discloses a chamber of

treatment comprising an internal cylindrical electrode surrounded by an electrode

outer ring finger. The tapered internal electrode at each end.

Quin US 5662031 discloses a treatment chamber comprising

an inner cylindrical electrode surrounded by an outer annular electrode. Both of them

the electrodes are provided with tapered surfaces.

Mittal US 6093432 discloses a treatment chamber comprising

a housing containing an inner electrode and an outer electrode disposed a

halfway along the length of the internal electrode. The internal electrode includes

a metal tube with a circular cross section, and the external electrode

comprises an annular disc having a hole in the center.

Bushnell US 6110423 discloses a processing cell comprising

a series of electrodes, both cylindrical in shape, separated by an insulating section. There

configuration of the chamber presents variations in radius such as to allow the

maximum concentration of electric field strength near the ray s ti. 1 020 1 60 0 o? / <■>? i 1 0

minor.

Bushnell WO 00/00044 discloses a treatment chamber with a

internal electrode coaxial to an external electrode that surrounds it. The apparatus has a

inlet manifold of substantially uniform cross-section and

extending from a distance of at least twice the average manifold diameter of

entrance before the treatment area. The internal electrode with an ogival shape.

Jayaram and Kameshwara in WO 2005/107821 A1 have proposed a

type of treatment room that differs from those already mentioned below

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different aspects: it is in fact made up of two electrodes of opposing convex sections

defining a treatment zone biconcave between them.

WO2011 / 092247 discloses a device comprising a matrix of

electrodes in which the surfaces therebetween are disposed and axially spaced along the

product flow path. The electrodes are kept separate by an insulator and the

channel through flows the product and annular in shape.

Van Den Bosch in WO 2014/042526 A1 proposes a room

comprising an annular treatment zone disposed between inlet and outlet e

having a cross section at least as large as the section area

transversal of the inlet manifold, an internal conveyor in the shape of an ogive and that

it widens from the center of the chamber towards the treatment area such as to make the

laminar flow, a first and a second electrode such as to provide an electric field

axial in said treatment zone. 3⁄4 From the analysis of the above documents, which represent the current state

of the art, it is clear that no devices have yet been envisaged such that, a

all other conditions being equal, it is allowed to vary the intensity of the field

electric applied.

The purpose of the invention in question is to overcome the problems and problems

drawbacks of the prior art described above.

In particular, an object of the present invention is to provide a

device, an integral part of a treatment chamber, for the abatement

microbiological liquid food products, able to allow the possibility of

being able to vary the intensity of the electric field with all other conditions being equal

operational.

Another object of the present invention is to provide a device which

is easy to clean and maintain, and quick to wash with very low losses of

prevalence.

The structural and functional characteristics of the present invention and its advantages

will be even more clear and evident from the claims below, and in

particular from an examination of the following description, referring to the attached figures, which

show a preferred but not limiting embodiment of the device in

object, in which:

Figure 1 is a schematic view of a preferred but not limiting form

for the implementation of the device for carrying out an abatement treatment

microbiological analysis of liquid food products in question, in a first position

operational; And

Figure 2 is a schematic view of the device of Figure 1 in one

second operating position.

With reference to the attached figures, a device is globally indicated with Z

for the realization of a treatment of microbiological abatement of products

liquid foodstuffs of the present invention.

The device Z comprises a CT treatment chamber consisting of at least two

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concentric electrodes. The two electrodes both have a truncated cone shape such as

maintain, in the treatment area inside the CT chamber, the respective ones

perfectly parallel surfaces and at the same time allowing them to vary

distance between them as the inner electrode has the possibility of

translate sideways in a direction parallel to the flow of the product with respect to the other

electrode (or uter electrode) placed outside the CT chamber (Figure 1).

In the present description, the treatment area means that part of the

CT treatment chamber in which the two electrode surfaces, external and internal,

they are parallel (section AB in Figure 1) and the distance is the shortest between them.

It is therefore considered that bacterial inactivation occurs only in this specification

part of the CT treatment chamber and treatment time means time

necessary for the food product to pass through said section of the chamber CT.

It is clear at this point that being able to vary the distance between the electrodes from one

minimum which corresponds to the point where the electrodes are in contact to a maximum

in which the internal electrode is substantially outside the external electrode, involves

the possibility, all other conditions being equal, to vary the intensity of the field

electric in a very simple way and with extreme precision.

In Figure 1, specifically, the inclination of the surfaces of the two electrodes with respect to the

parallel plane represented by the direction of flow of the food product is of

about 10.42 degrees.

It therefore follows that for each millimeter of lateral translation, the distance of the

electrodes in the treatment area varies by exactly 0.1805mm and, like

any other configuration with different inclination, can be managed in a

this gap is very precise.

The lateral translation of the internal electrode can be exerted by a piston

pneumatic, electric motor or other suitable system to generate a bidirectional movement.

The internal electrode connected to this motor system through the shaft C (Fig. 1) which slides inside a cylinder made of insulating material which also has the purpose of isolating the two electrodes and avoiding direct contact (Fig. . 2 insulator component indicated with I).

It is connected to the pulse generator by means of an electric cable of suitable shape and material.

The shaft C also has the function of allowing the cooling of the internal electrode for this purpose, suitably provided with an internal cavity in which a coolant liquid flows.

The circuit is equipped with an inlet D and an outlet E of said fluid, and can be open to loss or closed to recirculation.

The external electrode coupled to the remaining part of the circuit through stubs F made of insulating material such as technopolymers or vitreous material (e.g. borosilicate,

ceramic glass, calcium sodium etc).

The second socket may be preferable as it allows visual internal inspection of the Z device.

Both electrodes do not have any sharp edges or angular shapes and all the parts where the configuration changes in inclination have been rounded to avoid peaks of concentration of the electric field with possible arc discharges.

The present invention also provides for the cooling of the external electrode but, unlike the first, it is preferable that it takes place with air or refrigerant gas.

The system includes an external casing that covers the electrode creating a cavity and in which there are an inlet G and an outlet H of the gas.

cooling down.

This choice derives from the possibility of using a single refrigerating system (Chiller) which, by cooling the gaseous fluid of the external electrode, conveys this to a radiator, also allowing the cooling of the liquid fluid and keeping the two circuits electrically isolated. It goes without saying that one of the advantages of the present invention for low viscous fluids consists in the fact that the construction of the pulse feeders can be greatly simplified since there is no need to provide modulations of any kind in the delivery of power.

On the other hand, as regards the treatment of high and very high viscosity fluids, it is possible to use, if necessary, both treatment chambers with variable distance, as envisaged in this document, and power supplies with modulable power supply.

The present device Z is of particular importance in sectors such as dairy and liquid egg products in which the present invention can advantageously be used in combination with heat treatment.

traditional to obtain greater microbiological abatements at the same temperature or obtain similar abatements using decidedly lower process temperatures while greatly preserving the nutritional and organoleptic characteristics of the food.

In these sectors, the same pasteurization-sterilization systems are used to process very different products from a chemical-physical point of view such as milk, yogurt or mascarpone, or yolk and whole liquid eggs.

These types of products with different viscosities and conductivity are thermally treated with different process parameters, temperatures and flow rates, it follows that it would be necessary to replace the internal or external electrode at each

Claims (6)

<■> M <'> w product change. A second aspect of significant importance in the food industry sector it concerns the correct cleaning and sanitization of the CT chamber. The washing of the production plants normally takes place with flow rates from two to three times higher than normal production capacities and in any case with minimum speeds from equal to 2-2.5 mt / sec. The configurations envisaged up to now for the treatment chambers provide for distances fixed between the electrodes by a few millimeters (on average from 3 to 15) with consequent significant head losses and increase in pressures during washing. In this case, the permitted advantage of the present device Z is to be able to translate the internal electrode to the point such as to obtain the maximum flow passage equal to inner diameter of the outer electrode. CLAIMS 1. Device (Ζ) for carrying out a microbiological abatement treatment of liquid food products fed into a treatment chamber (CT), comprising at least two concentric electrodes provided with respective parallel surfaces (AB) to each other; characterized in that one of said electrodes is arranged inside said chamber (CT) and being able to translate with respect to the other electrode arranged externally to said chamber (CT) to vary the distance with respect to the other external electrode itself in a direction parallel to a feed flow of said product. 2. Device according to claim 1, characterized in that said two electrodes have a substantially frusto-conical shape. 3. Device according to claim 1 or 2, characterized in that the inclination of the surfaces of said two electrodes with respect to the parallel plane represented by the direction of the said flow of the said alimerftare product is about 10.42 degrees. 4. Device according to one or more of claims 1 to 3, characterized in that said internal electrode is able to be connected to a motor unit through a relative shaft (C); said shaft (C) being able to slide inside a cylinder (I) made of insulating material to isolate said two electrodes from each other, avoiding direct contact thereof. 5. Device according to claim 4, characterized in that said shaft (C) is also able to allow the cooling of said internal electrode, being suitably provided with an internal cavity in which a coolant liquid flows. 6. Device according to one or more of the preceding claims 1 to 5, characterized in that said two electrodes have rounded edges for