WO2006105959A1

WO2006105959A1 - Process and plant for the treatment of vegetable protein materials

Info

Publication number: WO2006105959A1
Application number: PCT/EP2006/003114
Authority: WO
Inventors: Giuseppina Cerea
Original assignee: Vomm Chemipharma SRL
Current assignee: Vomm Chemipharma SRL
Priority date: 2005-04-06
Filing date: 2006-04-05
Publication date: 2006-10-12
Anticipated expiration: 2007-10-06
Also published as: WO2006105959A8; CN1843148A; ITMI20050579A1

Abstract

A process for treating a vegetable protein material, such as for example gluten or soybean proteins, in order to increase its digestibility, comprising the steps of : feeding a continuous flow of such protein material into a turbo-reactor (A) feeding concurrently into the turbo-reactor (A) a continuous and finely divided flow of a reactant consisting of a concentrated aqueous hydrogen peroxide solution, centrifuging the protein material and the reactant against the inner wall of the turbo-reactor heated at a temperature of 50°- 100 °C, reacting the protein material and the reactant while progressing in substantial contact with said inner wall of the turbo-reactor (A) continuously discharging a flow of treated protein material, having a humidity content of 20-30%, sending such flow of treated protein material on to a maturation step and to a subsequent drying step.

Description

Title: Process and plant for the treatment of vegetable protein materials

DESCRIPTION

Field of application

The present invention relates to the field of the food, dietetics and cattle industry and in particular, it concerns a process for treating vegetable protein materials in order to obtain highly digestible de-texturized products.

Throughout the description, specific reference will be made to gluten but it should be understood that also other vegetable protein materials, such as for example soybean proteins, can be subjected to the treatment according to the process of the present invention.

Prior art

The use of vegetable protein materials is constantly increasing in both human and animal foodstuffs following dieticians' and nutritionists' recommendations for the reduction of human intake of animal proteins, and of the well known problems arising from the use of animal protein materials in animal breeding, especially with cattle.

The digestibility of vegetable protein materials, soybean proteins especially, is, however, generally poor, and the use of some of these materials, in particular gluten, is limited by the well known intolerance reactions suffered by a considerable percentage of consumers. Summary of the invention

An object of the present invention is to provide vegetable protein materials having greater digestibility and solubility, as well as improved organoleptic properties, so as to make them apt for human and animal consumption.

Such an object is achieved, according to the invention, by a process for treating a vegetable protein material, comprising the steps of:

-feeding a continuous flow of said material into a turbo-reactor comprising a horizontal-axis cylindrical tubular body, provided with at least one opening for introducing reactants and for discharging the treated product, a heating jacket for bringing the inner wall of the tubular body to a predetermined temperature, a bladed rotor, rotatably supported in the cylindrical tubular body where it is put into rotation at peripheral speeds comprised between 15 and 40 m/s, so as to disperse said continuous flow of protein material into a flow of particles of the same,

feeding into said turbo-reactor, cocurrently with said protein material flow, a continuous and finely divided flow of a reactant consisting of a concentrated aqueous hydrogen peroxide solution,

centrifuging said protein material particles and said reactant against the inner wall of the turbo-reactor, heated at a temperature of at least 60⁰C, with formation of a thin, dynamic, highly turbulent tubular fluid layer wherein the protein material particles and said reactant are mechanically kept in close contact by the blades of said bladed rotor,

reacting said protein material and said reactant within said thin layer while progressing in substantial contact with said inner wall of the turbo-reactor towards the discharge opening,

continuously discharging a flow of treated protein material, having a humidity content of 20-30%,

sending said flow of treated protein material on to a maturation step for a time varying between 30 minutes and 20 h, at a temperature of 50- 100⁰C, and to a subsequent drying step to bring the humidity content below 10%.

The treated protein material exiting the turbo-reactor generally has a temperature of about 40-80⁰C.

The above-mentioned concentrated hydrogen peroxide solution preferably consists of an aqueous solution of hydrogen peroxide of at least 40-volumes and, advantageously, of about 120-140 volumes.

When 120-140 V hydrogen peroxide is used, the weight ratio of hydrogen peroxide to protein material generally varies between 1:4 and 1:20. The concentrated aqueous hydrogen peroxide solution can be introduced into the turbo-reactor right at the inlet, since in that case the bladed rotor carries out an effective nebulization and centrifugation thereof, thus ensuring its introduction into the turbulent dynamic thin layer of protein material particles to be treated in a highly dispersed condition.

In this way, the closest possible contact between the particles and the hydrogen peroxide is promoted, and this considerably increases the efficacy of the treatment.

As an alternative or in addition to the above-mentioned introduction through an inlet opening, the hydrogen peroxide introduction may also be carried out through openings for the nebulization of hydrogen peroxide at different levels along the length of the cylindrical tubular body.

It can sometimes be advantageous to introduce a steam flow cocurrently with the above-mentioned protein material flow into the turbo-reactor.

The mean residence time of the protein material flow inside the turbo- reactor is of about 1-5 minutes.

The above-mentioned maturation step at 50-100⁰C can be carried out in static conditions, for example inside heating silos with plate-type heat exchangers as those manufactured by the Bulkflow Technologies Inc. (Canada) company.

Alternatively, and preferably, the maturation at 50-10O⁰C is carried out in dynamic conditions, in order to prevent undesirable agglomeration and increase the homogeneity of the end product, for example by means of a slow continuous stirrer or a screw apparatus. This latter apparatus advantageously consists of a horizontal-axis cylindrical tubular body, provided with inlet and discharge openings, a heating jacket for bringing the inner wall of the tubular body to a predetermined temperature, and a screw supported in the cylindrical tubular body where it is put into rotation at low speeds.

The drying step mentioned above can be carried out with any apparatus commonly used for drying powdery substances but it is preferably carried out with the aid of a turbo-dryer, which is an apparatus structurally similar to the turbo-reactor described above, also comprising a horizontal-axis cylindrical tubular body, provided with inlet and outlet openings, with heating jacket and with a bladed rotor rotatably and coaxially mounted inside the cylindrical tubular body.

When such apparatus is used, the temperature of the heating wall is of about 120-160⁰C and, cocurrently with the flow of treated protein material entering the turbo-dryer, a hot and dry air flow is optionally fed at a temperature of 120-160⁰C. The mean residence time of the treated protein material inside the turbo-dryer is of about 1-5 minutes. The expression "vegetable protein material" includes, in particular, gluten from different sources (e.g. wheat, barley, maize, oats, rye) and soybean proteins.

With reference to gluten, following the treatment with hydrogen peroxide carried out according to the process of the present invention, it is substantially de-texturized and modified in the tertiary structure of the two components, gliadin and glutenin, more soluble and digestible than the starting gluten.

As a consequence of such modifications, it is particularly suitable for being used as an additive for low-gluten starches or flours in the production of bakery products, e.g. biscuits, that must not undergo changes in dimensions during the dough mixture laying steps. The dough mixes from starchy meals which have been supplemented with gluten treated according to the present process in fact exhibit poor spring back properties.

Moreover, still due to the modifications undergone in the tertiary structure, gluten loses, to a great extent, its ability to cause food intolerances and can be suitable for the production of food for celiacs.

With reference to soybean proteins, following the treatment with hydrogen peroxide according to the process of the present invention, they are made more soluble and digestible and therefore particularly suitable for integration in cattle feeds.

The treatment according to the present invention further produces a sterilization of soybean proteins from the microbiological standpoint, the destruction of any alpha-toxins present therein and a deodorization thereof, which makes them especially suitable for being used in foods for human consumption.

In another aspect thereof, the present invention concerns a plant for carrying out the process illustrated above, which comprises a turbo- reactor of the type described above, a screw apparatus for the maturation of the treated protein material as described above, and a dryer, preferably a turbo-dryer.

The advantages and features of this invention will appear more clearly from the description of an embodiment of a process according to the invention, hereinafter provided with reference to the annexed drawing, given for illustrative and non-limiting purposes.

Brief description of the drawings

Figure 1 schematically shows a plant for treating vegetable protein material in order to increase its solubility and digestibility according to the process of the invention.

Detailed description of a preferred embodiment

With reference to figure 1, the turbo-reactor A essentially consists of a cylindrical tubular body 1, closed at the opposed ends by end walls 2, 3 and coaxially provided with a heating jacket 4 intended to be run through by a fluid, for example diathermic oil, for keeping the inner wall of body 1 at a predetermined temperature.

The tubular body 1 is provided with inlet openings 5, 6 for the protein material to be treated and for the concentrated aqueous hydrogen peroxide solution, respectively, as well as a discharge opening 7 for the treated protein material.

Inside the tubular body 1 is rotatably supported a bladed rotor 8 , the blades 9 of which are helically arranged and are oriented for centrifuging and concurrently conveying the protein material subjected to treatment towards the outlet.

A motor M is provided for driving the bladed rotor at peripheral speeds varying between 20 and 40 meters per second.

Openings 10 are provided in the inner wall of the cylindrical tubular body 1 for introducing concentrated aqueous hydrogen peroxide solution in nebulized form.

A plant for obtaining vegetable protein material with higher solubility and digestibility characteristics according to the process of the invention comprises, in addition to the turbo-reactor A, a maturation apparatus B and a turbo-dryer C. The maturation apparatus B, shown in a very schematic manner, comprises a cylindrical tubular body 21, closed at the opposed ends by end walls 22, 23 and coaxially provided with a heating jacket 24 intended to be run through by a fluid, for example diathermic oil, for keeping the inner wall of the body 1 at a predetermined temperature.

The tubular body 21 is provided with an inlet opening 25 for the protein material coming from the turbo-reactor A and with a discharge opening 27 for the protein material at the end of the maturation step.

A screw 28 is rotatably supported in the tubular body 21, driven in rotation at low speed by a motor N and intended for conveying the protein material subjected to maturation towards the outlet.

Finally, the turbo-dryer C is not described in detail as it has a structure entirely similar to that of turbo-reactor A, except for the absence of openings for the introduction of liquid reactants. The components of turbo-dryer C that are the same as those of the turbo-reactor A are indicated with same reference numerals increased by 100.

EXAMPLE

In a turbo-reactor A wherein the bladed rotor is made to rotate at a peripheral speed of about 30 m/s and wherein the inner wall is kept at 100⁰C, a flow of powdered wheat gluten (humidity content of about 5%) is continuously fed, at a flow rate of 100 kg/hour. At the same time, 40 1/hour of a 1:1 mixture of 130 V hydrogen peroxide and water are continuously fed through opening 6 and openings 10.

Right at the inlet of the turbo-reactor A, the powdery gluten flow is mechanically dispersed into very small particles, which are immediately centrifuged against the inner wall of the turbo-reactor itself, where they form a dynamic tubular thin layer.

At the same time, the aqueous hydrogen peroxide solution entering through opening 6 is mechanically finely nebulized by the blades 9 of rotor 8, which also readily centrifuge the very small droplets obtained. These are thus introduced into the dynamic tubular thin layer of gluten particles with which they can interact.

The hydrogen peroxide solution introduced in nebulized form through the openings 10 further increases the interaction of the hydrogen peroxide with the gluten particles.

After a residence time of about 1 minute inside the turbo-reactor A, treated gluten is continuously discharged from opening 7 with a humidity content of about 25% and a temperature of about 60⁰C.

The flow of treated gluten exiting the turbo-reactor A is continuously fed to the maturation device B, through the inlet opening 25. The gluten is made to slowly progress up to the discharge opening 27 by the slowly rotating screw 28, after a mean residence time of about 2 hours at a temperature of about 70⁰C (which is also the temperature at which the inner wall is stabilized by the heating jacket 24).

At this point, the gluten flow coming out of the maturation device B is continuously fed into turbo-dryer C, through the inlet opening 105, along with a cocurrent air flow at about 140⁰C. After a mean residence time of about 1 minute inside the turbo-dryer, in which the bladed rotor 108 is put into rotation at a peripheral speed of 30 m/s and the heating jacket 104 stabilizes the temperature of the inner wall at about 140⁰C, the gluten is discharged through the discharge opening 107.

The resulting gluten has a humidity content of about 5%.

Claims

1. Process for treating a vegetable protein material in order to increase its digestibility, comprising the steps of:

feeding a continuous flow of said protein material to a turbo-reactor (A) comprising a horizontal- axis cylindrical tubular body (1), provided with at least one opening (5, 6) for introducing said material and reactants, at least one discharge opening (7) for the treated material, a heating jacket (4) for bringing the inner wall of the tubular body (1) to a predetermined temperature, a bladed rotor (8), rotatably supported in the cylindrical tubular body where it is put into rotation at peripheral speeds comprised between 15 and 40 m/s, so as to disperse said continuous protein material flow into a protein material particle flow,

feeding into said turbo-reactor (A), cocurrently with said protein material flow, a continuous and finely divided flow of a reactant consisting of a concentrated aqueous hydrogen peroxide solution,

centrifuging said protein material particles and said reactant against the inner wall of the turbo-reactor, heated at a temperature of 50°- 100⁰C, with formation of a thin, dynamic, highly turbulent tubular fluid layer wherein the protein material particles and said reactant are mechanically kept in close contact by the blades (9) of said bladed rotor (8), reacting said protein material and said reactant within said thin layer while progressing in substantial contact with said inner wall of the turbo-reactor (A) towards the discharge opening (7),

sending said flow of treated protein material on to a maturation step for a time varying between 30 minutes and 20 h, at a temperature of 50- 100⁰C, and to a subsequent drying step to bring the humidity content of the end protein material below 10%.

2. Process according to claim 1, wherein said concentrated hydrogen peroxide solution consists of hydrogen peroxide of at least 40 volumes.

3. Process according to claim 2, wherein said concentrated hydrogen peroxide solution consists of hydrogen peroxide of 120-140 volumes.

4. Process according to claim 3, wherein the weight ratio of hydrogen peroxide to protein material varies between 1:4 and 1:20.

5. Process according to any one of the previous claims, wherein said maturation step at 50-100⁰C is carried out in an apparatus (B) comprising a horizontal-axis cylindrical tubular body (21) provided with at least one inlet opening (25), at least one discharge opening (27), a heating jacket (24) for bringing the inner wall of the tubular body (21) at a predetermined temperature comprised between 50 and 100⁰C, and a screw (28) supported in rotation in the cylindrical tubular body (21).

6. Process according to any one of the previous claims, wherein said drying step is carried out in a turbo-dryer (C) comprising a horizontal- axis cylindrical tubular body (101) provided with openings (105, 106) for introducing said treated and matured protein material, discharge openings (107) for the end product, a heating jacket (104) for bringing the inner wall of the tubular body (101) at a temperature of 120-160⁰C, a bladed rotor (108), rotatably supported in the cylindrical tubular body where it is put in rotation at peripheral speeds comprised between 15 and 40 m/s.

7. Process according to claim 6, wherein an air flow at a temperature of 120-160⁰C is fed into the turbo-dryer (C), cocurrently with said flow of treated and matured protein material.

8. Process according to any one of the previous claims, wherein said vegetable protein material consists of gluten or soybean proteins.

9. Plant for carrying out the process according to any one of the previous claims, comprising:

- a turbo-reactor (A) comprising a horizontal-axis cylindrical tubular body (1), provided with at least one opening (5, 6) for introducing said protein material and reactants, at least one discharge opening (7) for the treated product, a heating jacket (4) for bringing the inner wall of the tubular body (1) to a predetermined temperature, a bladed rotor (8), rotatably supported in the cylindrical tubular body;

- a maturation apparatus (B) comprising a horizontal-axis cylindrical tubular body (21) provided with at least one inlet opening (25), at least one discharge opening (27), a heating jacket (24) for bringing the inner wall of the tubular body (21) to a predetermined temperature, and a screw (28) supported in rotation in the cylindrical tubular body (21)

- a dryer.

10. Plant according to claim 9, wherein said dryer consists of a turbo- dryer (C) comprising a horizontal-axis cylindrical tubular body (101), provided with at least one opening (105, 106) for introducing said treated and matured protein material, at least one discharge opening (107) for the end product, a heating jacket (104) for bringing the inner wall of the tubular body (101) to a predetermined temperature, a bladed rotor (108), rotatably supported in the cylindrical tubular body.

11. Gluten having increased water solubility and improved digestibility obtained through the process according to claim 8.