Process for the production of a vegetable protein concentrate

Abstract

The invention relates to the field of processing vegetable raw materials, and concerns in detail a process for the production, preferably from soybean and / or pea seeds, of a vegetable protein concentrate in the form of flour. Said process for the production of a vegetable protein concentrate comprises the steps of: - providing soybean and / or pea seeds; - brushing said seeds to remove the dust deposited on them and simultaneously eliminate the dust by suction; - drying said seeds to dilate and at least partially raise the pericarp from the endosperm below; - heating the surface of said seeds in order to eliminate vegetative microbial forms and spore-forming strains; - hulling said seeds to permanently separate the pericarp from the endosperm and simultaneously remove the separate pericarp by means of suction; - grinding the hulled seeds to obtain a protein flour. More in general, the same process can also be applied to other vegetable seeds or grains, provided that they have an adequate protein value. The invention also concerns a plant that applies said process and the vegetable protein flour that is obtained.

Description

[0001] PROCESS FOR THE PRODUCTION OF A VEGETABLE PROTEIN CONCENTRATE

[0002] Technical field of application

[0003] The invention relates to the field of processing vegetable raw materials, and concerns in detail a process for the production, preferably from soybean and / or pea seeds, of a vegetable protein concentrate in the form of flour.

[0004] More in general, the same process can also be applied to other seeds or vegetable grains provided that they have an adequate protein content.

[0005] The invention also concerns a plant that applies said process and the vegetable protein flour that is obtained.

[0006] Background art

[0007] In recent years there has been an increase in consumer demand for products, also among industrial processed and semi-finished products, which are of guaranteed vegetable origin and which retain the qualitative characteristics, biological value and natural functionality of the original raw materials, and which also take the environmental profile into due consideration.

[0008] Naturally, in order to aspire to obtaining products with such characteristics, the original vegetable material must be subjected to treatments, which in turn must ensure the desired ecological respect not only of the product following treatment, but also of the conditions of the process and of the reagents and solvents used to perform it. Currently, the quality of the production processes used, their environmental sustainability and preserving the characteristics of the raw material in the final product, especially in the food sector, but also in related sectors such as animal husbandry, represent the main market demands in industrialized countries.

[0009] Vegetable soybean flour is a particulate obtained from soybeans, and in particular obtained as by-product of the extraction of soybean oil.

[0010] To date, there are two methods most used for the extraction of soybean oil from the seeds: an extraction method by pressing, from which the so-called soybean cake is obtained, to then be sent to a grinding step; and an extraction method using solvents with subsequent grinding of the soybean flakes from which the lipid part has been removed.

[0011] In the first case, without particular pre-treatment of the seeds, at least two pressing stages are required to obtain oil, with the negative consequence of increasing the temperature, up to 140°C, with a modification of the organoleptic properties of the oil.

[0012] In the case of chemical extraction, the solvent most widely used is hexane (boiling point between 66° and 69°C); in order to recover the solvent, extraction is followed by a step of heating with vapour current distillation (over 15 minutes of treatment with temperatures of over 100°C). Also in this case, the subsequent process to obtain protein flour suffers from chemical pollution deriving from the oil extraction process. In brief, the industrial process to obtain a soybean protein flour as by-product of oil extraction with solvents can be schematized as follows:

[0013] - cleaning using a magnetic separator and screen;

[0014] - rough crushing;

[0015] - rolling with unheated rollers, with the formation of soybean “flakes” of medium thickness;

[0016] - extraction of the lipid content with hexane at around 60°C;

[0017] - heating with recovery of the solvent, where the spent soybean “flakes” are treated with wet heat in order to remove the solvent through vapour current distillation;

[0018] - cooling and milling.

[0019] Known production processes to obtain a soybean protein flour have limits and disadvantages mainly concerning total degradation of the proteins present in the soybeans due to the temperatures and to the chemical treatments to which they are subjected.

[0020] The proteins, which represent the nutritional component that soybeans are most rich in and for which the flour is produced to be used as a supplement to animal feed, but also above all to human nutrition, are partly destroyed by the treatment with solvents and by the subsequent heating required to eliminate these solvents.

[0021] A further disadvantage, common both to the extraction method by pressing and to the extraction method with solvents, concerns the risk of possible contamination of the flour with dusts or soil matter present on the pericarp of the seeds that are not eliminated before the extraction step and are thus carried to the final milling step, ending up in the flour.

[0022] Moreover, known processes do not include any step of reducing the microbial loads on the initial raw material, i.e., on the seeds.

[0023] Presentation of the invention

[0024] The main objects of the invention are to produce a process for the production of a vegetable protein concentrate in the form of flour that that is developed in a few quick operating steps and can be implemented through an efficient, simple, reliable and safe plant, which retains all the nutritional characteristics of the raw material, above all the proteins, in compliance with all health and hygiene standards.

[0025] The objects are achieved with a process for the production of a vegetable protein concentrate characterized in that it comprises the steps of:

[0026] - providing soybean and / or pea seeds;

[0027] - brushing said seeds to remove the dust deposited on them and simultaneously eliminate the dust by suction;

[0028] - drying said seeds to dilate and at least partially raise the pericarp from the endosperm below;

[0029] - heating the surface of said seeds in order to eliminate vegetative microbial forms and spore-forming strains;

[0030] - hulling said seeds to permanently separate the pericarp from the endosperm and simultaneously remove the separated pericarp by means of suction; - grinding the hulled seeds to obtain a protein flour.

[0031] Further features of the production process of the invention are described in the dependent claims.

[0032] The invention also relates to a plant that implements such process and the vegetable protein flour obtained.

[0033] The main advantages of the invention are the following.

[0034] In the process of the invention the proliferation of bacterial microorganisms is eliminated thanks to the step of initial brushing of the seeds, the step of sanitizing the seeds by heating, and to the rapid removal of the fibrous part of the pericarp from the endosperm part of the seed during hulling.

[0035] The process of the invention, which maintains temperatures within controlled values, without peaks and steps of prolonged heating, allows maximum preservation of the functional characteristics of the native protein present in the seeds.

[0036] The temperatures at play in the whole of the production process are such as not to harm the nutritional principles contained in the seeds, in particular the proteins that the soybean and / or pea seeds are rich in and which are essential for the quality of the flour obtained. The heating steps to which the seeds are subjected during the process have a limited and / or restricted value and duration, such as not to deteriorate the nutritional values of the final flour.

[0037] The vegetable protein flour obtained at the end of the process does not contain residues of solvents, does not contain plasticizers, and the risk of cross contamination is avoided. The entire process is carried out in a continuous line, and the passages from one work station to the next take place without risk of contamination.

[0038] Brief description of the drawings

[0039] Further features and advantages of the invention will be more evident from the more detailed description set forth below with the aid of the figures, which represent preferred embodiments thereof, illustrated by way of non-limiting example, wherein:

[0040] - Figs. 1 and 2 represent, by means of block diagrams, the main steps of a process for the production of a vegetable protein concentrate in the form of flour according to two possible variants of the invention.

[0041] Detailed description of a preferred embodiment of the invention

[0042] With the aid of Fig. 1 , there are illustrated the main steps of a process for the production of a vegetable protein concentrate in the form of flour, produced in particular from soybean and / or pea seeds and preferably intended to be used for the production of a wet textured product.

[0043] Fig. 1 also schematizes the main stations of a plant 100 for the implementation of this process.

[0044] The process according to the invention starts with the sourcing of soybean and / or pea seeds having specific characteristics: the seeds are of selected genetics, cultivated in Italy and hence GMO-free by law.

[0045] Said process essentially comprises the following steps: - providing soybean and / or pea seeds;

[0046] - brushing said seeds to remove the dust deposited on them and simultaneously eliminate the dust by suction;

[0047] - drying said seeds to dilate and at least partially raise the pericarp from the endosperm below;

[0048] - heating the surface of said seeds in order to eliminate vegetative microbial forms and spore-forming strains;

[0049] - hulling said seeds to permanently separate the pericarp from the endosperm and simultaneously remove the separated pericarp by means of suction;

[0050] - grinding the hulled seeds to obtain a protein flour.

[0051] In a preferred embodiment of plant that implements such process, the seeds are provided in bags and poured into a tower storage station 1 complete with discharge hopper having a processing capacity of 1000 kg / h.

[0052] During all the process steps the seeds, at the various stages of processing, are fed by means of a cable conveyor system, produced with a tubular and modular system, where the product (first seeds, then cotyledon, then flour), is drawn inside pipes 5 by chains equipped with curved discs that ensure a precise and constant flow rate of product.

[0053] The seeds are then fed to a brushing machine 2, advantageously with an output of 600 kg / h of dry product, complete with a system for air suction 6 and elimination of the dust removed, of the type with centralized sleeves, which operates continuously. After brushing, the seeds pass to the drying step which comprises the use of infrared lamps 7 at a process temperature below 55°C.

[0054] Said drying step comprises the step of making the degree of humidity of said seeds uniform until bringing the endosperm to a humidity of 6-10%. Preferably, upon exiting the drying step, the seeds have a degree of humidity of 8% at the endosperm.

[0055] The use of an infrared dryer makes it possible to ensure that the process temperature does not exceed 55°C and that, thanks to radiation, an initial separation of the pericarp from the endosperm below occurs, which will then facilitate the hulling step.

[0056] Following the drying step, the process comprises the step of heating seeds for the purpose of sanitizing them. Such heating affects the surface of the seeds.

[0057] Upon exiting the dryer, the seeds are in fact spread out and oscillated on a vibrating table 8 radiated once again with infrared lamps 9, taking the temperature of the pericarp to temperatures close to 70° C for no more than 120” in order to eliminate vegetative microbial forms and partially eliminate spore-forming strains.

[0058] Upon exiting the heating and sanitization step, the seeds, already standardized in humidity content and prepared for immediate removal of the pericarp, are conveyed to the hulling step, which is carried out by mechanical exfoliation and comprises the use of a disc huller 3 with differentiated conical profile having a processing capacity of 600Kg / h.

[0059] Said step of hulling said seeds comprises the step of removing the separated pericarp, and comprises the use of a two-step aeroconvective separator 10: a first cyclone gravimetric separation step and a second triboelectric separation step

[0060] Immediate separation of the pericarp, and hence of the fibre part, from the cotyledon prevents the latter from coming into contact with the outer surface of the pericarp where most of the microbial forms present on the seeds are concentrated.

[0061] Once the seed has been broken into the two cotyledons and stripped of the pericarp, it is immediately ejected by centrifugal force inside an aeroconvective separator 10, provided with micro-nozzles that create a toroid of high speed air adapted to immediately separate the cotyledons from the pericarp. The pericarp, due to lower density and greater aerodynamic lift, is thrust and made to swirl in a second toroid, provided immediately above the first, where the cotyledon fragments that are discharged tangentially to the toroid through a separate exit with respect to the pericarp, are also swirling.

[0062] The pericarp delivered from the upper toroid, and already electrically charged by rubbing, is swirled against the walls of a cyclone of suitable shape made of a material that is charged with the opposite charge, allowing microfibres to be separated from cotyledon fragments of small size, which are in turn recycled together with the heavier cotyledon part.

[0063] The pericarp and all of the separated fibrous part are collected in a specific box 15.

[0064] The cotyledon part is sent to the milling step, to obtain flour, which comprises the use of a disc mill 4 having a processing capacity of 2500-3000kg / h.

[0065] Said mill 4 preferably comprises a manual system for adjusting the distance between milling discs.

[0066] Upon exiting the mill, the flour obtained is subjected to a selection step of its particle size, by means of screen 11 .

[0067] Preferably said screen 1 1 is capable of separating from two to three fractions: first fraction ranging from 300 to 150 micron, second fraction ranging from 150 to 80 micron, and third fraction below 80 micron.

[0068] The flour selected exiting from the process illustrated in Fig. 1 , sent to a storage station 12, is adapted to be used for the production of a wet textured product and comprises a size, 90% of which is below 100 micron.

[0069] With the aid of Fig. 2, the main steps of a production process of a vegetable protein concentrate, in the form of flour produced in particular from soybean and / or pea seeds and preferably intended for the production of a wet textured product, and which thus includes an intermediate step of oil extraction.

[0070] Said Fig. 2 also schematizes the main stations of a plant for the implementation of said process.

[0071] The process starts with the same steps illustrated above of:

[0072] - providing soybean and / or pea seeds;

[0073] - brushing said seeds to remove the dust deposited on them and simultaneously eliminate the dust by suction;

[0074] - drying said seeds to dilate and at least partially raise the pericarp from the endosperm below; - heating the surface of said seeds in order to eliminate vegetative microbial forms and spore-forming strains;

[0075] - hulling said seeds to permanently separate the pericarp from the endosperm and simultaneously remove the separated pericarp by means of suction.

[0076] However, the hulled seeds are not immediately fed to the mill 4 for milling, but pass through a step of de-oiling to take them to a fat content of less than 10%.

[0077] Said step of de-oiling said hulled seeds comprises a continuous pressing step with process temperature below 55°C, through the use of a continuous screw press 13.

[0078] The pressing step takes place in a single stage without raising the temperature of the seeds and of the oil above 55°C. This is possible thanks to a preventive step of rolling said hulled seeds, or their cotyledons.

[0079] A step of heavy rolling, carried out in a specific rolling mill 14, allows cold disintegration of the cells of the endosperm in order to subsequently facilitate pressing.

[0080] Seed oil and a cake, in the form of a floury product obtained from the residues of the seeds after pressing, are delivered from the press 13.

[0081] The oil is collected in a specific tank 16.

[0082] The cake obtained from pressing can be sent to the milling step to obtain a flour with a low fat content.

[0083] The seed cake is fed from above to the mill 4 which, just as for the process of Fig. 1 , produces a flour to be screened 11 before being sent to the storage station 12.

[0084] Unlike the wet flour produced with the process and plant of Fig. 1 , with the stage intermediate to the de-oiling step characterizing the process of Fig. 2, a flour with a lower content of fats and lipids is obtained, with a size ranging from 250 to 100 micron, particularly adapted to be used for the production of a dry textured product.

[0085] EXAMPLE

[0086] By way of example, the results of chemical-physical-biological tests on a vegetable protein flour obtained from a variety of soybeans of the line NAV® marketed by the company Sipcam Italia S.p.A. are shown below, these test were carried out in conformity with the provisions of Ministerial Decree 27.11.03 relating to the Method of checking corn and soya seeds for the presence of genetically modified organisms, by means of the process of the invention, with particular reference to the variant schematized in Fig. 2 which includes the step of de-oiling the hulled seeds before milling.

[0087]

[0088]

Claims

CLAIMS1 . A process for the production of a vegetable protein concentrate characterized in that it comprises the steps of:- providing soybean and / or pea seeds;- brushing said seeds to remove the dust deposited on them and simultaneously eliminate the dust by suction;- drying said seeds to dilate and at least partially raise the pericarp from the endosperm below;- heating the surface of said seeds in order to eliminate vegetative microbial forms and spore-forming strains;- hulling said seeds to permanently separate the pericarp from the endosperm and simultaneously remove the separated pericarp by means of suction;- grinding the hulled seeds to obtain a protein flour.

2. The process according to claim 1 , characterized in that said step of drying said seeds comprises the step of making the degree of humidity of said seeds uniform until bringing the endosperm to a humidity of 6-10%.

3. The process according to claim 1 , characterized in that said step of drying said seeds comprises the use of infrared rays at a process temperature below 55°C.

4. The process according to claim 1 , characterized in that said step of heating the surface of said seeds has a duration of less than 120 seconds, being adapted to bring the temperature of the pericarp to a value around 70°C.

5. The process according to claim 1 , characterized in that said step of heating the surfaces of said seeds comprises the use of a vibrating table radiated by infrared rays.

6. The process according to claim 1 , characterized in that said step of hulling said seeds is carried out by mechanical exfoliation and comprises the use of a disc huller with differentiated conical profile.

7. The process according to claim 1 , characterized in that said step of hulling said seeds comprises the step of removing the separated pericarp, comprises the use of an aeroconvective separator and is carried out in a first cyclone gravimetric separation step and in a second triboelectric separation step.

8. The process according to claim 1 , characterized in that said step of grinding the hulled seeds comprises the use of a disc mill.

9. The process according to claim 1 , characterized in that it comprises a selection step, by means of screen, for selecting the particle size of the flour coming out of said milling step.

10. The process according to claim 1 , characterized in that between said step of hulling said seeds and said step of grinding the hulled seeds is a step of de-oiling said hulled seeds until bringing them to a lipid content below 10%.11 . The process according to claim 10, characterized in that said step of de-oiling said hulled seeds comprises a continuous pressing step with process temperature below 55°C.

12. The process according to claim 10, characterized in that prior to said step of de-oiling the hulled seeds is a step of rolling saidhulled seeds.

13. A plant for the production of a vegetable protein flour adapted to implement the process according to at least one of the claims 1 - 12.

14. The vegetable protein flour obtained by means of the process according to at least one of the claims 1 -9, characterized in that it is adapted to be used for the production of a wet texturized product and comprises a size, 90% of which is smaller than 100 micron.

15. The vegetable protein flour obtained by means of the process according to at least one of the claims 1 -12, characterized in that it is adapted to be used for the production of a dry texturized product and comprises a size ranging from 250 to 100 micron.

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