WO2024125824A2 - Plant protein isolate extracted and enhanced via microbial strain - Google Patents

Abstract

The invention relates to a method for extracting plant proteins comprising the following steps: 1. suspending a plant flour in a preferably aqueous solvent, so as to obtain a plant flour suspension; 2a. adding a strain into the plant flour suspension of step 1; 2b. incubating the seeded suspension of step 2a so that the strain acidifies the seeded suspension until a protein precipitate is formed; and 3. separating the protein precipitate obtained at the end of step 2b. The invention also relates to a plant protein isolate capable of being obtained by the method of the invention.

Description

Description

PLANT PROTEIN ISOLATE EXTRACTED AND IMPROVED VIA MICROBIAL STRAIN

Technical area

[0001] The invention relates to the field of plant proteins, in particular protein isolates from legumes, even more particularly protein isolates from peas.

Prior art

[0002] Human daily protein requirements are between 12 and 20% of the food ration. These proteins are provided both by products of animal origin (meat, fish, eggs, dairy products) and by products of plant origin (cereals, legumes, algae).

[0003] However, in industrialized countries, protein intake is mainly in the form of proteins of animal origin. However, numerous studies show that excessive consumption of proteins of animal origin to the detriment of vegetable proteins is one of the causes of an increase in cancer and cardiovascular diseases.

[0004] Furthermore, animal proteins present many disadvantages, both in terms of their allergenic potential, particularly concerning proteins derived from milk or eggs, and on the environmental level in relation to the harmful effects of intensive breeding.

[0005] Thus, there is a growing demand from manufacturers for compounds of plant origin having interesting nutritional and functional properties without having the disadvantages of compounds of animal origin.

[0006] Soya was, and remains, the first plant-based alternative to animal proteins. The use of soy nevertheless has certain disadvantages. There Soybean is more than frequently of GMO origin and obtaining its protein goes through a de-oiling stage using a solvent.

[0007] Since the 1970s, grain legumes, including peas in particular, have developed significantly in Europe, mainly in France, as an alternative protein resource to animal proteins intended for animal and human food. Peas contain approximately 27% protein by weight. The term “pea” is considered here in its broadest sense and includes in particular all wild varieties of “smooth pea”, and all mutant varieties of “smooth pea” and “wrinkled pea”. (“wrinkled pea”), regardless of the uses for which said varieties are generally intended (human food, animal nutrition and/or other uses). These seeds are non-GMO and do not require solvent deoiling.

[0008] Pea protein, mainly pea globulin, has been extracted and used industrially for many years. Several processes exist that can be categorized into two large families: so-called “dry” processes and so-called “wet” processes. The first consist of the particle size reduction of legume seeds into flour followed by particle size separation using an ascending air current, a process commonly called turbo-separation. These processes lead to the production of protein concentrates whose protein richness does not exceed 60%-70%. These processes are not to be considered in the context of the present invention which falls within the field of isolates whose protein concentration is greater than these contents.

[0009] Concerning the second family of so-called “wet” processes, we can cite, as an example of a process for extracting pea protein, patent EP 1 400 537. In this process, the seed is crushed in the absence of water (a process known as “dry grinding”) in order to obtain flour. This flour will then be suspended in water in order to extract the protein by precipitation. Precipitation is carried out by adjusting the isoelectric pH and/or heating the medium.

[0010] Such processes have several disadvantages. The first lies in the use of acid-base reagents which are expensive, require investments for their storage and implementation. The latter are also dangerous for humans in that their contact without adequate protection causes significant lesions. The second consists of obtaining an isolate whose molecular integrity is affected, as well as the organoleptic profile. It is thus well known that heating under acidic conditions will potentially significantly modify protein molecules and cause the appearance of organovolatile compounds resulting from lipid degradation. Such compounds are for example hexanal or methanethiol.

[0011] It is therefore common and much work currently being done in the field of improvements to these processes replacing this isoelectric precipitation step with or without heating, or even adding additional process steps to compensate for these undesirable effects. The first solution unfortunately requires investment in membrane filtration techniques which are expensive and cumbersome to operate due to significant clogging of the filter media. The second solutions also have many limitations, if only due to the implementation of new steps in an already complex process. We can cite in particular the fermentation of legume seeds prior to the core extraction process of patent EP 3 071 046. If the final result obtained is interesting, the process involves heavy fermentation of more than 24 hours and the generation of water excessive residuals that will need to be treated.

[0012] A recent alternative route consists of the use of bacterial strains in order to replace the acid-base reagents during the precipitation step, described in the article Emkani et al., 2021 (Emkani et al., Foods, 10, 549, 2021: “Pea Protein Extraction Assisted by Lactic Fermentation: Impact on Protein Profile and Thermal Properties”). If this process seems interesting, it also has two disadvantages: hydrolysis or even consumption of the protein by the strain, and the fermentation time of around 5 hours to 6 hours, which is difficult to compatible with an industrial process. In the article “Protein composition and nutritional aspects of pea protein fractions obtained by a modified isoelectric precipitation method using fermentation” (Emkani et al., Frontiers in Nutrition, Volume 10, 2023) it is thus demonstrated a “degradation of proteins by LAB in small peptides and amino acids, which were solubilized in the soluble fraction (albumins) as confirmed by size exclusion chromatography (SEC-HPLC). ".

[0013] It is to the applicant's credit to have worked in this field and to have discovered a set of strains carrying out rapid acidification without hydrolysis, that is to say without consumption of the protein, as well as having developed the process using it with the aim of obtaining a protein isolate whose functional and organoleptic characteristics are optimized to a level never before achieved. In addition, the strains and the process according to the invention using them make it possible to obtain a plant protein isolate whose organoleptic performance is of certain interest for the food industry.

The invention will be better understood in the descriptive part of the present application which follows.

General description

The present invention relates to a process for extracting plant proteins comprising the following steps:

1. suspending a vegetable flour in a preferably aqueous solvent, so as to obtain a suspension of vegetable flour;

2a. adding a strain to the vegetable flour suspension of step 1, the strain being selected from the group consisting of Lactobacillus Fermentum, Lactobacillus Salivarius, Lactobacillus Delbrueckii subsp Jakobsenii, Lactobacillus Mucosae, Streptococcus Salivarius, and Enterococcus Lactis; the strain being preferentially a strain of Lactobacillus Fermentum; even more preferably the strain deposited with the CNM under the number CNCM I-5802, so as to form a seeded suspension;

2b. incubating the inoculated suspension from step 2a so that the strain acidifies the inoculated suspension until a protein precipitate is formed;

3. Separation of the protein precipitate obtained at the end of step 2b.

[0016] In one embodiment, the process according to the invention is characterized in that the vegetable flour of step 1 is in the form of a vegetable powder containing a quantity of protein greater than 1% by weight, preferably between 15% and 30% by weight, relative to the weight of powder.

[0017] In one embodiment, the process according to the invention is characterized in that the vegetable flour of step 1 is an isolate or a concentrate, preferably an isolate whose protein content is greater than 80% by dry weight on dry matter of isolate.

[0018] In one embodiment, the process according to the invention is characterized in that the vegetable flour of step 1 is a legume flour, preferably in that the vegetable flour is a legume flour selected from the group consisting of peas and fava beans, more preferably in that the vegetable flour is pea flour.

[0019] In one embodiment, the process according to the invention is characterized in that the incubation temperature of the suspension of step 2b is between 30°C and 50°C, preferably between 35°C and 45°C. °C.

[0020] In one embodiment, the process according to the invention is characterized in that the pH of the vegetable flour suspension from step 1 is rectified so as to be between 6.5 and 7.5; preferably so as to be equal to 7.0, before the implementation of step 2a.

[0021] In one embodiment, the method according to the invention is characterized in that the addition of strain in step 2a is carried out so as to obtain a seeded suspension having a strain concentration of between 0.1 × 10 ⁹ and 1.10 ⁹ Colonies Forming Unit (CFU) per milliliter of vegetable flour suspension.

[0022] In one embodiment, the process according to the invention is characterized in that the incubation of step 2b is carried out until the inoculated suspension has a pH of between 4 and 5, preferably a pH of 5.0.

[0023] In one embodiment, the method according to the invention is characterized in that if at the end of step 2b, the pH of the inoculated suspension is not between 4 and 5, the 'step 2b comprises at the end of step 2b a sub-step 2b' of acidification of the inoculated suspension by adding acid, so that the seeded suspension obtained at the end of step 2b has a pH between 4 and 5, preferably between 5 and 4.5.

[0024] In one embodiment, the method according to the invention is characterized in that step 2b comprises, at the end of step 2b, a sub-step 2b” of additional heating to increase the flocculation yield, consisting of carrying the suspension of vegetable flour from step 2b at a temperature between 45° and 85°C.

[0025] In one embodiment, the method according to the invention is characterized in that step 3 comprises the following steps:

3a. rectifying the pH of the seeded suspension obtained at the end of step 2b to a pH between 6 and 9, preferably a pH of 7, preferably by adding soda or lime to said suspension;

3b. heat treatment of the suspension from step 3a between 100°C and 160°C for 0.1 to 1 s, and

3c. drying the vegetable flour suspension from step 3b until obtaining a vegetable flour isolate having a dry matter greater than 95% using an atomizer.

The invention also relates to a plant protein isolate capable of being obtained by the process of the invention.

[0027] In one embodiment, the plant protein isolate according to the invention is characterized in that its degree of hydrolysis (or DH) is less than 10%, preferably less than 5.

[0028] In one embodiment, the plant protein isolate is characterized in that the methanethiol content is reduced by more than 25%, preferably by more than 50%, compared to an isolate obtained by acidification of a suspension of vegetable flour only by adding hydrochloric acid.

[0029] In one embodiment, the plant protein isolate is characterized in that its protein content is between 80% and 95% by weight, preferably between 82% and 92% by weight, preferably between 84% and 90% by weight. % by weight, preferably between 84% and 88% by weight, relative to the weight of total dry matter of the isolate.

[0030] The invention also relates to the use of the isolate according to the invention or obtained according to the process of the invention for industrial applications including food, nutraceutical and pharmaceutical applications.

[0031] The invention also relates to a microbial strain deposited with the CNCM under the number CNCM I-5802.

[0032] The invention also relates to a plant protein isolate characterized in that its hexanal content is less than 6000 μg/kg and its methanethiol content is less than 100 μg/kg.

[0033] The invention will be better understood on reading the detailed description below

detailed description

The present invention relates to the microbial strain deposited with the CNCM under the number CNCM I-5802.

This particular strain was identified as belonging to the Lactobacillus Fermentum group. As will be demonstrated in the example section, this stands out in an exceptional way by allowing acidification of a medium containing vegetable proteins, preferably pea proteins, both quickly and efficiently.

The CNCM I-5802 strain will be mainly used for plant protein extraction processes but also for any other activity requiring rapid acidification with reduced or even non-existent protein hydrolysis. These applications will be reviewed precisely and in a non-exhaustive manner later in this description.

The present invention therefore relates to a process for extracting plant proteins comprising the following steps:

1. suspending a vegetable flour in a preferably aqueous solvent, so as to obtain a suspension of vegetable flour;

2a. adding a strain to the vegetable flour suspension from step 1, strain being selected from the group consisting of Lactobacillus Fermentum, Lactobacillus Salivarius, Lactobacillus Delbrueckii subsp Jakobsenii, Lactobacillus Mucosae, Streptococcus Salivarius, and Enterococcus Lactis; the strain being preferentially a strain of Lactobacillus Fermentum; even more preferably the strain deposited with the CNCM under the number CNCM I-5802, so as to form a seeded suspension;

2b. incubating the inoculated suspension from step 2a so that the strain acidifies the inoculated suspension until a protein precipitate is formed;

3. Separation of the protein precipitate obtained at the end of step 2b.

[0037] The first step of the process therefore consists of the use of vegetable flour.

[0038] For the purposes of the invention, “plant flour” means any powder of plant origin containing a quantity of protein greater than 1%, preferably between 15% and 30% by weight, relative to the weight of powder.

[0039] In particular, within the meaning of the invention, flour obtained by grinding plant seeds will be understood. These seeds may undergo pretreatment such as cleaning, sieving, thermal heating, a quenching or bleaching step, sieving (separation of seeds from stones for example). Preferably, if bleaching is carried out, the heat treatment scale will be 3 minutes at 80°C.

[0040] Plant seeds consist of the structure containing and protecting the plant embryo. It is often contained in a fruit which allows its dissemination or protected by an external envelope often called a shell. These will be particularly selected from the list containing legumes and cereals.

[0041] For the purposes of the present invention, the term “legume” means the family of dicotyledonous plants of the Fabales order. It is one of the most important families of flowering plants, third after Orchidaceae and Asteraceae in number of species. It has approximately 765 genera bringing together more than 19 500 species. Several legumes are important cultivated plants including beans, peas, fava beans, lupine, beans, chickpeas, peanuts, cultivated lentils, cultivated alfalfa, various clovers, broad beans, carob, licorice.

[0042] Preferably, the legumes are selected from the list consisting of peas and fava beans, even more preferably peas.

[0043] The term "pea" being considered here in its broadest sense and including in particular all varieties of "smooth pea" and "wrinkled pea", and all mutant varieties of “smooth pea” and “wrinkled pea”, regardless of the uses for which said varieties are generally intended (human food, animal nutrition and/or other uses). The term “pea” in the present application includes the varieties of peas belonging to the genus Pisum and more particularly to the species sativum and aestivum. Said mutant varieties are in particular those called “r mutants”, “rb mutants”, “rug 3 mutants”, “rug 4 mutants”, “rug 5 mutants” and “lam mutants” as described in the article by C-L HEYDLEY and al. entitled “Developing novel pea starches” Proceedings of the Symposium of the Industrial Biochemistry and Biotechnology Group of the Biochemical Society, 1996, pp. 77-87.

[0044] The term “faba bean” is understood here as the group of annual plants of the species Vicia faba, belonging to the group of legumes of the family Fabaceae, subfamily Faboideae, tribe Fabeae. There are varieties Minor and Major. In the present invention, wild varieties and those obtained by genetic engineering or breeding are all excellent sources.

[0045] The vegetable flour will therefore be preferentially reduced to powder of finer particle size. All well-known techniques of the prior art will be compatible with the process according to the invention. We can cite, for example, knife mills. A particular and particularly suitable example of such a knife mill is for example the SM300 marketed by the company Retsch® or a stone mill for example marketed by the company Alma®.

The flour thus obtained is suspended in a solvent. This solvent is not intended to completely solubilize all of the same dry matter, even if this case is entirely conceivable. In a preferred mode, the conditions for suspending the flour are adapted to insolubilize the non-protein compounds in order to eliminate them and thus pre-enrich the solution with proteins.

Preferably, the solvent is water. This can nevertheless be supplemented, for example with compounds to facilitate solubilization.

Preferably, the pH of the aqueous solvent is adjusted between 8 and 10, preferably 9. Any basic reagent such as soda or lime is possible, but potash is preferred. The temperature is preferably adjusted between 2°C and 30°C, preferably between 10°C and 30°C, preferably between 15°C and 25°C, even more preferably at 20°C. This temperature is regulated throughout the extraction reaction.

The flour is diluted in the preferably aqueous solvent in order to obtain a suspension of between 5% and 25%, preferably between 5% and 15%, preferably between 7% and 13%, even more preferably between 9% and 11%. %, the most preferred being 10%, the percentage being expressed in weight of powder per total weight of water/powder suspension. The suspension is stirred using any equipment well known to those skilled in the art, for example a tank equipped with an agitator, equipped with blades, marine propellers, or any equipment allowing effective stirring. The extraction time, preferably with stirring, is between 5 and 25 minutes, preferably between 10 and 20 minutes, even more preferably 15 minutes.

[0050] Preferably, the suspension is then centrifuged in order to eliminate insoluble non-protein compounds such as, for example, starch and/or internal fibers also called pulp in the case of legumes.

[0051] In an alternative mode, vegetable seed flour is a material rich in proteins. By “protein-rich material” we mean any material in the form of powder, floc containing at least 25% protein by dry weight on dry matter. We can cite, in a non-limiting manner, concentrates, isolates, seeds. Preferably, the protein-rich material is in powder form.

[0052] Preferably, the material rich in pea proteins used for step 1 is an isolate, that is to say its protein content is greater than 80%. in dry weight on dry matter. The use of concentrates (protein content between 50% and 80% by dry weight on dry matter) or even flour (protein content less than 50% by dry weight on dry matter) can also be considered but isolate is preferred.

[0053] Obtaining material rich in pea proteins is easy with conventional art processes well known to those skilled in the art. We will cite for example the processes described in patent applications EP 1 909 593 or FR 2018052261 of the applicant. The basic principle of these processes (suspension of pea flour in water by wet or dry grinding, elimination of insoluble parts such as starch and internal fibers by centrifugation, isoelectric precipitation of the protein of interest) is classic now and very easily offers a suitable protein.

Whatever the process used to obtain the vegetable protein suspension (e.g. simply by adding water to a pea protein isolate or by starting from pea flour and eliminating internal fibers and starch), the final dry matter of said suspension (also called “crude extract”) will preferably be between 3% and 9%, which therefore includes the values 3%, 4%, 5%, 6%, 7%, 8% and 9%. The percentage is expressed in grams of dry matter per 100 grams of total weight of the protein suspension.

The second step of the method according to the invention comprises at least:

2a. adding a strain to the vegetable flour suspension of step 1, the strain being selected from the group consisting of Lactobacillus Fermentum, Lactobacillus Salivarius, Lactobacillus Delbrueckii subsp Jakobsenii, Lactobacillus Mucosae, Streptococcus Salivarius, and Enterococcus Lactis; the strain being preferentially a strain of Lactobacillus Fermentum; even more preferably the strain deposited with the CNM under the number CNCM I-5802, so as to form a seeded suspension,

2b. incubating the inoculated suspension from step 2a so that the strain acidifies the inoculated suspension until a protein precipitate is formed. [0056] The second step therefore consists in particular of acidifying the pH using a strain selected from Lactobacillus Fermentum, Lactobacillus Salivarius, Lactobacillus Delbrueckii subsp Jakobsenii, Lactobacillus Mucosae, Streptococcus Salivarius, and Enterococcus Lactis; preferably from a strain of Lactobacillus Fermentum; even more preferably of the CNCM I-5802 strain.

[0057] Preferably, the temperature of the protein suspension is regulated between 30°C and 50°C, preferably between 35°C and 45°C, therefore including the values of 30°C, 31°C, 32° C, 33°C, 34°C, 35°C, 36°C, 37°C, 38°C, 39°C, 40°C, 41°C, 42°C, 43°C, 44°C and 45°C;

Preferably, the starting pH is rectified between 6.5 and 7.5; preferably 7.0; which includes values of 6.5; 6.6; 6.7; 6.8; 6.9; 7.0; 7.1; 7.2; 7.3; 7.4 and 7.5. To do this, the Skilled Person will use any well-known material and reagent.

The strain selected from Lactobacillus Fermentum, Lactobacillus Salivarius, Lactobacillus Delbrueckii subsp Jakobsenii, Lactobacillus Mucosae, Streptococcus Salivarius, and Enterococcus Lactis; preferably Lactobacillus Fermentum; even more preferably the strain CNCM I-5802; is then preferably introduced at a concentration of between 0.1.10 ⁹ and 1.10 ⁹ CFU (meaning Colonies Forming Unit) per milliliter of suspension.

[0060] Preferably, the inoculate of the strain is prepared in the following manner, hereinafter referred to as “inoculate preparation method A”):

- The strain is stored in the form of a cryoball

- Seeding a 2L Erlenmeyer flask with 500 mL of MRS medium with 1 bead from a cryoball of the strain.

- Incubation for 18 to 24 hours in an anaerobic incubator, at a temperature of 37°C +/- 1°C and shaking at 80 rpm

- Transfer the contents of the Erlenmeyer flask into a centrifugation jar

- Centrifuge at 3000g for 10 minutes

- Eliminate the supernatant

- Resuspend the pellet with physiological water - Repeat the centrifugation/washing steps twice

- After the last centrifugation, take the pellet again in 10mL of physiological water

- Store the suspension thus obtained in ice or at 4°C while awaiting its implementation

- Creation of the correlation line between O.D. 600nm and CFU/ml. This is obtained by carrying out several 10-fold dilutions of the bacterial suspension, then by measuring both the O.D. 600nm and carrying out the CFU/ml count. Draw the curve CFU/ml = f(OD 600 nm). We can thus obtain by linear regression the correlation coefficient between OD 600nm and the number of CFU/ml allowing one to be calculated from the other.

- Carry out a measurement of D.0.600nm using a spectrophotometer on the suspension stored at 4°C (If necessary to dilute to obtain the measurement, the dilutions of the cell suspensions will be made in Tween 0.3% because biomass tends to stick to the walls of the dilution tubes)

- Determine the volume of inoculum to introduce into a given volume of crude protein extract to reach the concentration between 0.1.10 ⁹ and 1.10 ⁹ CFU (meaning Colonies Forming Unit) per milliliter of suspension.

[0061] Preferably and in order to exemplify, a suspension of the Lactobacillus fermentum strain CNCM I-5802 having an OD 600nm of 1 corresponds to a concentration of 3.0.10 ⁸ CFU/mL.

[0062] After introduction of the bacterial inoculum into the crude protein extract, agitation is carried out with any installation well known to those skilled in the art including an agitation axis equipped with a marine propeller. The stirring speed is preferably between 200 and 400 rpm, preferably 250 and 350 rpm.

[0063] The pH will quickly become acidic. Monitoring of changes in pH is carried out with a suitable probe. The maximum acidification speed (called Vm) expressed in pH units per min is typically between -0.030 and -0.020 pH units/min, preferably between -0.027 and -0.022 UpH/min. If the pH does not change (absence of acidification) or when the acidification speed is less than -0.020 pH units/min, it is possible to add an additional quantity of ferment in order to compensate for poor capacity at that this to acidify. The target pH is the so-called isoelectric pH for the protein that we wish to flocculate. For example, for the so-called globulin fraction of pea this pH is 5. This is likely to vary depending on the targeted protein. Through this natural acidification, the protein will flocculate and coagulate.

[0065] Preferably, an addition of an additional quantity of acid making it possible to finalize the acidification, e.g. to acidify from pH 5 to pH 4.5 can be carried out at the end of step 2b (sub-step 2b’).

Preferably, additional heating, preferably at the end of step 2b, is possible in order to increase the flocculation yield (sub-step 2b”). By “flocculation” is meant in the present invention the insolubilization of a portion of the proteins present in solution in order to be extracted. “flocculation” and “precipitation” can be used interchangeably here. The heating temperature is between 45° and 85°C, therefore including the values of 45°C, 46°C, 47°C, 48°C, 49°C, 50°C, 51°C, 52°C , 53°C, 54°C, 55°C, 56°C, 57°C, 58°C, 59°C, 60°C, 61°C, 62°C, 63°C, 64°C, 65 °C, 66°C, 67°C, 68°C, 69°C, 70°C, 71°C, 72°C, 73°C, 74°C, 75°C, 76°C, 77°C , 78°C, 79°C, 80°C, 81°C, 82°C, 83°C, 84°C and 85°C.

When the protein floc obtained is of the desired quality and quantity, it will conventionally be separated from the rest of the aqueous suspension, conventionally by static or dynamic decantation (plate centrifuge, horizontal decanters, etc.).

[0068] The floc thus obtained can be used such that or undergo one or more unit process steps including unit steps of purification (e.g. by chromatography, ultrafiltration), concentration (e.g. evaporation, drying), addition of chemical reagents (e.g. to adjust the pH) / enzymatic reagents (e.g. proteases) and/or heat treatment (e.g. pasteurization, HTST, sterilization).

[0069] A preferred example of post-treatment consists of 1) rectification at pH between 6 and 9, preferably 7 with preferential use of soda or lime, 2) heat treatment between 100°C and 160°C for 0.1 at 1s and 3) drying to a dry matter greater than 90%, preferably 95% using an atomizer. [0070] The present invention also relates to the plant protein isolate obtained or capable of being obtained by isoelectric precipitation with the use of a strain selected from Lactobacillus Fermentum, Lactobacillus Salivarius, Lactobacillus Delbrueckii subsp Jakobsenii, Lactobacillus Mucosae, Streptococcus Salivarius, and Enterococcus Lactis; preferably from a strain of Lactobacillus Fermentum; even more preferably of the strain CNCM I-5802.

[0071] This isolate obtained by isoelectric precipitation obtained using bacterial acidification is characterized compared to the prior arts, particularly the article Emkani et al., 2021 (Emkani et al., Foods, 10, 549, 2021 ) in that its degree of hydrolysis is invariant. Without being bound by any theory, it is the selection of strains and their implementation which allows the obtaining of this unique and unequaled result until now to the best of our knowledge. The absence of protease, a presence with a lower activity and/or a speed of combined acidifying metabolism allow this result to be obtained.

[0072] The plant protein isolate according to the invention is preferably characterized in that its degree of hydrolysis (or DH) is less than 10%, preferably less than 5.

[0073] The isolate according to the invention preferably has a degree of hydrolysis (or DH) less than 10%, preferably less than 5%, including the DH of 10%, 9%, 8%, 7%, 6 %, 5%, 4%, 3%, 2% and 1%.

[0074] The degree of hydrolysis can be determined by measuring the free amino nitrogen content by the OPA method disclosed in the article Nielsen et al., 2001 (Nielsen et al., Journal of Food Science, Volume 66, Issue, Pages 642-646, 2001 “Improved Method for Determining Food Protein Degree of Hydrolysis”) in relation to the total nitrogen measured by the DUMAS method according to standard ISO 16634-2:2016.

The Test for measuring the degree of hydrolysis described below is particularly preferred. Its principle consists of first determining the amino nitrogen content (free NH2 functions) on the protein sample (preferably with the MEGAZYME kit (reference K-PANOPA)), then determining the protein nitrogen content (total nitrogen therefore including the free and engaged NH2 functions) of the sample, and finally to calculate the degree of hydrolysis accessible via the ratio of these two measurements.

[0076] Determination of the amino nitrogen content:

[0077] The “amino nitrogen” groups of the free amino acids in the sample react with N-acetyl-L-cysteine and Ophthaldialdehyde (OPA) to form isoindole derivatives.

The amount of isoindole derivative formed during this reaction is stoichiometric with the amount of free amino nitrogen. It is the isoindole derivative which is measured by the increase in absorbance at 340 nm.

Into a 100 mL beaker, an exactly weighed test portion P* of the sample to be analyzed is introduced. This test portion will be 0.5 to 5.0 g depending on the amino nitrogen content of the sample. Approximately 50 mL of distilled water is added, homogenized and transferred into a 100 mL volumetric flask. 5 mL of 20% sodium dodecyl sulfate (SDS) are added and made up with distilled water to reach a volume of 100 mL. Stir for 15 minutes with a magnetic stirrer at 1000 rpm. Solution No. 1 is prepared by dissolving a tablet from bottle 1 of the Megazyme kit in 3 mL of distilled water and shaking until completely dissolved. One tablet should be provided per test. Solution no. 1 is prepared extemporaneously.

A blank, a standard and a sample are prepared directly in the spectrophotometer tanks under the following conditions:

-blank: introduce 3.00 ml of solution no. 1 and 50 μl of distilled water

-standard: introduce 3.00 ml of solution no. 1 and 50 μl of bottle 3 of the Megazyme kit -sample: introduce 3.00 ml of solution no. 1 and 50 μl of the sample preparation.

The contents of each cell are mixed and the absorbance measurement (A1) of the solutions is read after approximately 2 minutes using a spectrophotometer at 340 nm (spectrophotometer equipped with cells with an optical path of 1.0 cm, capable of measuring at a length of wave of 340 nm, and checked according to the operating procedure described in the manufacturer's technical manual which relates to it).

The reactions are then started immediately by adding 100 μl of solution no. 2 which corresponds to the OPA solution from bottle 2 of the Megazyme kit in each spectrophotometer tank.

The contents of each tank are mixed and placed in the dark for approximately 20 minutes.

The A2 absorbance measurement of the blank, the standard and the sample is then read on the spectrophotometer at 340 nm.

The free amino nitrogen content, expressed as a percentage by weight relative to the weight of the product, is given by the following formula:

[Math.1]

où : [Math .2]

Or :

ΔAech =Aech2 - Aech1

ΔAblc =Ablc2 - Ablc1

Aech2 = absorbance of the sample after addition of solution no. 2

Aech1 = asorbance of the sample after addition of solution no. 1

Ablc2 = absorbance of the white after addition of solution no. 2

Ablc1 = absorbance of the white after addition of solution no. 1

V = volume of the vial m = mass of the test portion in g

6803 = extinction coefficient of the isoindole derivative at 340 nm (in L. mol ^-1 . cm ^-1 ).

14.01 = molar mass of nitrogen (in g. mol ^-1 )

3.15 = final volume in the tank (in mL)

0.05 = test portion in the tank (in mL)

[0078] Determination of the protein nitrogen content:

[0079] The protein nitrogen content is determined according to the DUMAS method according to standard ISO 16634 - 2016. It is expressed as a percentage by weight relative to the weight of the product. [0080] Calculation of the degree of hydrolysis:

The degree of hydrolysis (DH) is calculated with the following formula:

[Math.3]

The isolate obtained according to the process of the invention is also characterized by a reduced methanethiol content. As will be exemplified in the present application, during conventional acidification for example. with hydrochloric acid we observe the synthesis of this compound resulting from the degradation of sulfur amino acids. Its presence in the ppb range is sufficient to give a so-called “rotten egg” or “hydrogen sulphide” flavor when the isolate is used to prepare ready-to-drink beverages or wet extrusion strips intended to produce meat analogues. . Without being bound by any theory, these processes, by generating significant heat, will cause a significant appearance of degradation compounds from methanethiol. The process according to the invention preferably makes it possible to obtain an isolate whose methanethiol content is reduced by more than 50%, preferably by more than 25%, the reduction values potentially being 50%, 49%, 48 %, 47%, 46%, 45%, 44%, 43%, 42%, 41%, 40%, 39%, 38%, 37%, 36%, 35%, 34%, 33%, 32%, 31%, 30%, 29%,

28%, 27%, 26%, 25%, 24%, 23%, 22%, 21%, 20%, 19%, 18%, 17%, 16%, 15%,

14% 13% 12%, 11% 10%, 9%, 8% 7%, 6%, 5%, 4% 3%, 2% or 1%. The process according to the invention preferably makes it possible to obtain an isolate whose methanethiol content is less than 0.1 ppb, that is to say an isolate comprising less than 0.1 μg of methanethiol per kg of isolate. Preferably, the process according to the invention makes it possible to obtain an isolate whose methanethiol content is less than 0.01 ppb, that is to say an isolate comprising less than 0.01 μg of methanethiol per kg of isolate. Even more preferably, the process according to the invention makes it possible to obtain an isolate whose methanethiol content is less than 0.001 ppb, or in other words whose content is less than 1 ppt (part trillion; 1 ppt = 1 ng /kg, i.e. an isolate comprising less than 0.01 μg of methanethiol per kg of isolate

[0081] The plant protein isolate according to the invention is characterized in that its protein content expressed relative to its total dry matter is preferably between 80% and 95%, preferably between 82% and 92%, preferably between 84% and 90%, preferably between 84% and 88%.

[0082] The invention also relates to a plant protein isolate characterized in that its hexanal content is less than 6000 μg/kg and its methanethiol content is less than 100 μg/kg.

[0083] By “hexanal” (or hexanaldehyde), according to the invention is meant the organic compound of the aldehyde family, of the crude formula C6H12O, isomer of hexanone. Its CAS number is 66-25-1.

[0084] By “methanethiol” (or methyl mercaptan) is meant according to the invention I organosulfur compound of chemical formula CH3SH. It is a colorless gas from the thiol family whose odor is reminiscent of rotten cabbage. Its CAS number is 74-93-1.

[0085] The impact of volatile compounds in the aromatic profile of pea proteins has been well known for decades, in particular hexanal. While hexanal is important, other volatile compounds are also important to control. Recently, methanethiol was highlighted as the main important leading to sulfur aromas (see “Characterization of odor-active compounds of various pea preparations by GC-MS, GC-O, and their correlation with sensory attributes” (Zhogoleva & al., Future Foods, volume 8, available online in June 2023).

[0086] The dosage of these compounds is conventionally carried out using gas phase chromatography, equipped with a mass spectrophotometer. Many protocols exist, and the person skilled in the art will know how to find & adapt in order to quantify these compounds. A particularly preferred protocol is described in paragraph 168 of this application.

[0087] The hexanal content is less than 6000 μg/kg, preferably less than 5500 μg/kg, preferably less than 5000 μg/kg, preferably less than 4500 μg/kg, preferably 4000 μg/kg, preferably 3500 μg/kg . [0088] The methanethiol content is less than 120 μg/kg, preferably less than 110 μg/kg, preferably less than 100 μg/kg, preferably less than 90 μg/kg, preferably 80 μg/kg, preferably 70 μg/kg , preferably 65 μg/kg. The methanethiol content could therefore be 119, 118, 117, 116, 115, 114, 113, 112, 111, 110, 109, 108, 107, 106, 105, 104, 103, 102, 101, 100, 99, 98, 97, 96, 95, 94, 93, 92, 91, 90, 89, 88, 87, 86, 85, 84, 83, 82,

81, 80, 79, 78, 77, 76, 75, 74, 73, 72, 71, 70, 69, 68, 67, 66, 65, 64, 63, 62, 61, 60,

59, 58, 57, 56, 55, 54, 53, 52, 51, 50, 49, 48, 47, 46, 45, 44, 43, 42, 41, 40, 39, 38,

37, 36, 35, 34, 33, 32, 31, 30, 29, 28, 27, 26, 25, 24, 23, 22, 21, 20, 19, 18, 17, 16,

15, 14, 13, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1 μg/kg as well as all the sub-ranges formed with these values as limits. For example, the methanethiol content will be between 100 μg/kg and 50 μg/kg; preferably between 90 μg/kg and 60 μg/kg, preferably between 80 μg/kg and 60 μg/kg, even more preferably between 70 μg/kg and 60 μg/kg.

[0089] The plant protein isolate according to the invention is preferably characterized in that its degree of hydrolysis (or DH) is less than 10%, preferably less than 5.

[0090] Also, the invention relates to the application of the plant protein isolate obtained with the use of the CNCM I-5802 strain in nutritional formulations in dairy or vegetable drinks, in yogurt-type fermented milks (brewed, at the same time). Greek, to drink) and in dairy or vegetable creams, frozen desserts or sorbets.

[0091] First of all, the invention concerns the application of the isolate according to the invention in biscuits, muffins, pancakes, nutritional bars (intended for specialized nutrition/slimming or sports), in breads or gluten-free breads. enriched with proteins, small cereals obtained by high-protein extrusion cooking (“crisps”), where we are particularly looking for high-protein solutions without negative impact on the preparation process or the texture of the preparations or finished products.

[0092] For the purposes of the invention, the term “powdered nutritional formulations” means powdered formulations comprising at least, preferably only, a protein from a legume, and in particular from pea or fava bean, according to the invention, which are reconstitutable with an aqueous liquid, and which are suitable for oral administration to a human being.

[0093] The term "dry blend" as used herein, unless otherwise indicated, refers to the mixing of components or ingredients to form a basic nutritional powder or, to the addition of a dry component, in powder or granule or a powder-based ingredient to form a powdered nutritional formulation.

[0094] All percentages, parts and ratios, as used herein, refer to the weight of the total formulation unless otherwise stated.

[0095] The powdered food formulations and corresponding manufacturing processes of the present invention may comprise, consist of or consist essentially of the essential elements of the invention as described herein, as well as any additional or optional elements described herein or otherwise useful in nutritional formulation applications.

[0096] The powdered nutritional formulations of the present invention are generally in the form of flowable or substantially fluid particulate compositions, or at least particulate compositions that can be easily molded and measured using a spoon. or other similar device, wherein the compositions can easily be reconstituted by the intended user with an aqueous solution, typically water, to form a liquid nutritional formulation for immediate oral or enteral use. In this context, use "immediately" generally means within about 48 hours, more typically for about 24 hours, preferably immediately after reconstitution.

[0097] The powdered food formulations can be formulated with all types and sufficient quantities of nutrients so as to form a food supplement, or a specialized nutritional formulation intended for use in people following a particular diet intended for sports dietetics. and slimness.

[0098] In exemplary embodiments, the nutritional powder formulation can be formulated for use: to repair the muscles after intense effort, for example in athletes, - to ensure that athletes maintain or build muscle mass, or

- as a meal replacement for people wishing to lose weight via a satiety effect.

[0099] Powdered food formulations may have a caloric density adapted to the nutritional needs of the end user, although in most cases reconstituted powders comprise from about 350 to about 400 kcal/100 ml.

[0100] The powdered food formulations can have a protein level adapted to the nutritional needs of the end user, although in most cases, the reconstituted powders comprise from approximately 20 to approximately 91 g of protein / 100 g, including comprised of approximately 40 to approximately 65 g of protein / 100g.

[0101] Thus, the formulation can comprise between 20 and 95% of proteins relative to the total weight of the formulation, for example between 20-90%, 30-80%, or 40-60%.

[0102] For example, the protein isolate from legumes, preferably from pea or fava bean, according to the present invention can represent 40-50%, 50-60%, 60-70%, 70-80%, 80-90 % or 90-100% of the total protein in the formulation, or any combination of these percentage ranges. 100% representing the ultimate preferential mode to maximize the effect of FGF19 overexpression.

[0103] Furthermore, the powdered food formulations can have a fat content adapted to the nutritional needs of the end user, although in most cases, the reconstituted powders comprise from approximately 0.5 to approximately 13 g /100 g, including from about 3 to about 7 g /100 g. Thus, the formulation can comprise between 0 and 20% of lipids relative to the total weight of the formulation, for example between 0.5-15%, 1-10%, or 3-7% (in particular % by weight).

[0104] The powdered nutritional formulations of the present invention can be packaged and sealed in single or multi-use containers and then stored under ambient conditions for up to about 36 months or more, more typically from about 12 to about 24 month. [0105] For multi-use containers, they may be opened and covered for repeated use by the end user, provided that the covered package is then stored under ambient conditions (e.g. avoid extreme temperatures) and content used in about a month or two.

[0106] The areas of application of the nutritional formulations according to the invention are in particular:

- dietary nutrition (sport, slimming),

- clinical nutrition (in the form of a drink, dessert cream or enteral bag),

- dairy products (in the form of yogurts, dairy drinks, dairy creams, frozen desserts or sorbets).

- biscuit products, pastry products, bread products and high-protein cereal products.

[0107] In the field of sport, it is known that proteins participate in the maintenance and growth of muscle. Protein intake is also important for athletes who practice bodybuilding or muscle strengthening.

[0108] These proteins must be balanced in terms of amino acid profile and must comply with the recommendations of the FAO/WHO. Their digestibility is an important factor ranging from rapid digestibility to slower digestibility depending on the timing of protein intake.

[0109] Ready-to-drink protein or high-protein drinks then allow the body to benefit from a protein intake of choice, minus the calories.

[0110] These high-protein drinks must:

- be rich in proteins, low in carbohydrates and fats;

- to have good taste ;

- be designed to help lose weight, by stimulating fat loss and helping muscle recovery;

- be satiating;

- help you cope with cravings, without added sugars or fats;

- present a balanced content of essential amino acids, fiber, vitamins and minerals;

- be low-calorie.

[0111] These ready-to-drink drinks can advantageously be prepared with protein isolates from legumes, preferably from fava beans or peas, in accordance with the invention. They can also be used as the sole source of proteins, preferably because they maximize the effect of overexpression of FGF19.

[0112] For example, alternative vegetable drinks to cow's milk contain on average 4.5 to 11 g of protein per 100 ml of drink, preferably of the order of 7 g of protein per 100 ml, and are very low in fiber (around 0.5 to 1 g per 100 ml).

[0113] Thus, the drink can include between 1 and 20% protein relative to the total weight of the drink, for example between 3-15%, or 6-8%.

[0114] For example, the pea protein isolate according to the present invention can represent 50-60%, 60-70%, 70-80%, 80-90% or 90-100% of the total protein, or a any combination of these percentage ranges. Preferably, it represents at least 52%. Notably, pea protein intake is between 52 and 100% of total protein intake.

[0115] For ready-to-drink drinks, the pea protein intake can range from 0 to 100%, preferably from 0.01 or 0.1 to 100%. For example, the pea protein isolate according to the present invention may represent 0.1-10%, 10-20%, 20-30%, 40-50%, 50-60%, 60-70%, 70- 80%, 80-90% or 90-100% of total protein, or any combination of these percentage ranges.

[0116] In the field of “slimming” drinks, ie intended to be used in low-calorie diets or intended for weight loss, as mentioned previously, these protein or protein-enriched drinks are not only effective for rapid weight gain. muscles. This type of drink is also very advantageous as part of a slimming diet based on protein consumption. [0117] It is known that slimming drinks are ideal for helping with weight loss. More specifically, they allow:

- provide an effect of satiety

- protect the muscles and tone the body, avoiding weight gain.

[0118] As with “sports” drinks, these slimming drinks present:

- a balanced content of essential amino acids, fiber, vitamins and minerals

- reduced sugar, fat and calorie content.

[0119] This is why protein drinks are indeed very effective for quickly losing a few pounds. These protein-rich preparations simply reduce or stop the feeling of hunger in the person who consumes them. By taking such a drink, for example, the user can considerably reduce the quantity of food to consume, and enable rapid weight loss (as part of a meal replacement process for weight control, or weight loss replacement). the total daily ration for weight control).

[0120] In clinical nutrition, it is known that enteral nutrition is a therapeutic tube nutrition solution which is used when the digestive tract is functional and accessible but when the patient cannot eat normally or in cases of malnutrition. severe.

[0121] This technique makes it possible to deliver nutrients directly to the digestive tract. It replaces, totally or partially, traditional oral nutrition with “complete” nutritional formulas providing all the nutrients necessary for the body.

[0122] These formulas are generally packaged in flexible bags (in PVC) and administered by means of nasogastric or gastrostomy, nasojejunal, nasoduodenal or jejunostomy tubes.

[0123] These nutritional mixtures are composed of proteins, lipids, carbohydrates, vitamins and minerals with or without fiber.

[0124] Several categories are distinguished: polymeric mixtures (standard) and semi-elemental mixtures (“predigested”), the latter being indicated in very specific cases (short bowel syndrome, exocrine pancreatic insufficiency, etc.):

- Polymeric mixtures

- hypocaloric (0.5 - 0.75 kcal/ml), normo or hyperprotein, with or without fiber

- isocaloric (1 kcal/ml), normo or hyperprotein, with or without fiber

- hypercaloric (1.25 -1.5 kcal/ml) normo or hyperprotein, with or without fiber

- specific formulas (glycemic metabolism disorders, respiratory insufficiency).

[0125] Semi-elementals are iso- or hypercaloric normo or hyperprotein mixtures, based on peptides and medium-chain triglycerides.

[0126] Pea protein isolates, as a protein source, by their functional properties are particularly well suited to this use.

[0127] Furthermore, they make it possible to preserve the same properties as milk proteins, at a lower cost.

[0128] The invention will be better understood with the following examples which only aim to make it better understood. These have no restrictive scope.

Examples

[0129] Example 1: Process according to the invention starting from pea flour

[0130] Mixing 2 kg (expressed in commercial mass) of smooth yellow pea flour (85% dry matter and 28% N6.25 protein by dry weight) with demineralized water (20°C). The suspension obtained is homogenized for 30 minutes using a RAYNERI benchtop stirrer equipped with a dispersion turbine. The suspension thus obtained is centrifuged at 1000 g for 5 minutes in a BECKMAN laboratory centrifuge. Approximately 7 kg of supernatant with 7% dry matter (DM) is recovered after elimination of the pellet containing the insoluble part, mainly a fiber/starch mixture. The supernatant thus obtained is called “crude extract” and is standardized by rectifying its dry matter to 6%.

[0131] This set of steps leading to the raw extract is hereinafter referred to as “process head”. [0132] The acidification of the crude extract is then carried out according to the following protocol: Preculture

- Strain: CNCM I-5802

- Inoculum: 1 cryoball

- Middle: MRS broth (Man Rogosa Sharpe), ready to use, Sigma ref.69966

- Incubation for 24 hours at 37°C

- The biomass obtained is concentrated, washed 3 times with physiological water at 4°C

- The quantity to be added to 900ml of crude extract at 6% MS is calculated to obtain a cell concentration of 10 ⁹ CFU/mL according to the inoculate preparation method A described above (OD=1 <-> 3.10 ⁸ CFU/mL)

Culture :

- 2L DasGip® fermenter.

- Reaction volume: 900mL of crude extract at 4°C

- Agitation is regulated at 300 rpm, temperature 40°C

- Rectification of the pH to 7 in order to normalize it before sowing

- Seeding the fermenter with the quantity of preculture making it possible to obtain the cell concentration of 10 ⁹ CFU/mL calculated at the end of the preculture step.

- Monitoring the evolution of the pH using the Dasgip® pH meter (natural acidification of the extract by the strain)

- A control is carried out in parallel under the same conditions but without strain introduced in order to check the absence of an unwanted contaminant disrupting the process

[0133] The parameters of the acidification reaction are as follows:

- Witness :

- The control remained at pH 7 without becoming acidic, which validates the absence of contaminants

- In the presence of the strain:

- The acidification time to reach pH 5 was 110 min

- The Vm (or average speed of acidification) was 2 pH units acidified in 110 min, i.e. -0.018 U.pH/min (expressed in pH units per min, the sign expressing acidification) -The VM (or Maximum Acidification Speed) was -0.027 U.pH/min recorded at 42 min of reaction at a pH of 6.24.

[0134] We note that the fermentation time is very short compared to the teaching of Emkani et al., 2021 (Emkani et al., Foods, 10, 549, 2021) which describes a fermentation time between 350 and 500 min depending on the strain, more than 3 times longer than with the CNCM I-5802 strain.

[0135] The suspension at the end of acidification is centrifuged at 1000 g for 5 min at 6°C. The supernatant (which can be kept for analysis) is removed and replaced with the same quantity of sterile demineralized water. The suspension thus obtained is stirred to homogenize it and adjust the pH to 7. After 15 minutes of stirring and visual inspection of good homogeneity, the suspension is lyophilized for analysis under the reference “Example 1 according to the invention”

[0136] Example 2: Repeatability of Example 1:

[0137] The principle here is to reproduce, from the same pea flour, three times the same process as that described in Example 1.

[0138] The parameters of the acidification reaction are summarized in the following Table 1:

[Table 1]

[0139] The suspensions at the end of acidification are centrifuged at 1000 g for 5 min at 6°C. The supernatant (which can be kept for analysis) is removed and replaced with the same quantity of sterile demineralized water. The suspension thus obtained is stirred to homogenize it and adjust the pH to 7. After 15 minutes of stirring and visual inspection of good homogeneity, the suspension is lyophilized for analysis under the reference “Example 2.1/2.2./2.3 according to 'invention'. [0140] Example 3 - Process according to the invention starting from a pea isolate

[0141] The process can be applied to a pea protein isolate (e.g. Nutralys® F85M from the company Roquette) which makes it possible to simplify the process head of Example 1. We just make a suspension containing 6% dry matter with pea protein isolate and drinking water.

[0142] The suspension is then acidified according to the following protocol:

Preculture

- Strain: CNCM I-5802

- Inoculum: 1 cryoball

- Middle: MRS broth (Man Rogosa Sharpe), ready to use, Sigma ref.69966

- Incubation for 24 hours at 37°C

- The biomass obtained is concentrated, washed 3 times with physiological water at 4°C

- The quantity to be added to 900ml of 6% crude extract is calculated to obtain a cell concentration of 10 ⁹ CFU/mL according to the inoculate preparation method described above A (OD=1 <-> 3.1 Op ⁸ CFU/mL) Culture:

- 2L DasGip® fermenter.

- Reaction volume: 900mL of crude extract at 4°C

- Agitation is regulated at 300rpm, temperature 40°C

- Rectification of the pH to 7 without regulation (natural acidification carried out by the strain).

- Monitoring the evolution of pH using the Dasgip® pH meter

- A control is carried out in parallel under the same conditions but without strain introduced in order to check the absence of an unwanted contaminant disrupting the process

[0143] Example 4: Process outside the invention acidification with hydrochloric acid:

[0144] This process is carried out in order to generate a protein floc representing that obtained by the conventional process of the prior art. [0145] The head of the process is the same as that of Example 1 in order to generate a crude extract containing 6% MS.

[0146] The acidification is carried out with stirring, aiming for pH 5 with 1 N HCl. The temperature applied is 60° C. and is maintained thus for 10 minutes.

[0147] The suspension at the end of acidification is centrifuged at 1000 g for 5 min at 6°C. The supernatant (which can be kept for analysis) is removed and replaced with the same quantity of sterile demineralized water. The suspension thus obtained is stirred to homogenize it and adjust the pH to 7. After 15 minutes of stirring and visual inspection of good homogeneity, the suspension is lyophilized for analysis under the reference “Example 4 outside the invention - HCl acidification”

[0148] Example 5: Process outside the invention - acidification with strains not allowing the invention to be carried out and/or obtained:

[0149] The aim here is to demonstrate the importance of the strains used. The protocol is almost identical to that described in Example 1.

[0150] Mixing 2 kg (expressed in commercial mass) of smooth yellow pea flour (85% dry matter and 28% N6.25 protein by dry weight) with demineralized water (20°C). The suspension obtained is homogenized for 30 minutes using a RAYNERI benchtop stirrer equipped with a dispersion turbine. The suspension thus obtained is centrifuged at 1000 g for 5 minutes in a BECKMAN laboratory centrifuge. Approximately 7 kg of supernatant containing 7% material is recovered after elimination of the pellet containing the insoluble part, mainly a fiber/starch mixture. The supernatant thus obtained is called “crude extract” and is standardized by rectifying its dry matter to 6%.

[0151] The acidification of the crude extract is then carried out according to the following protocol:

Preculture

- Strain: several strains are compared, the list will be presented in the table below

- Inoculum: 1 cryoball

- Middle: MRS broth (Man Rogosa Sharpe), ready to use, Sigma ref.69966

- Incubation for 24 hours at 37°C - The biomass obtained is concentrated, washed 3 times with physiological water at 4°C

- The quantity to be added to 900ml of 6% crude extract is calculated to obtain a cell concentration of 10 ⁹ CFU/mL according to the inoculate preparation method A described above (OD=1 <-> 3.10p8 CFU /mL)

Culture :

- 2L DasGip® fermenter.

- Reaction volume: 900mL of crude extract at 4°C

- Agitation is regulated at 300rpm, temperature 40°C - Rectification of the pH to 7 without regulation (natural acidification carried out by the strain).

- Monitoring the evolution of pH using the Dasgip® pH meter

- A control is carried out in parallel under the same conditions but without strain introduced in order to check the absence of an unwanted contaminant disrupting the process.

[0152] The parameters of the acidification reaction are as follows:

[0154] Il est clair que seules les souches recommandées pour réaliser l’invention (en gras) permettent d’obtenir une acidification à pH 5 dans un temps inférieur à 130 min. Ceci est un avantage indéniable pour un procédé industriel. [0153] [Table 2]

[0154] It is clear that only the strains recommended for carrying out the invention (in bold) make it possible to obtain acidification at pH 5 in a time of less than 130 min. This is an undeniable advantage for an industrial process.

[0155] To complete this table, several analyzes are carried out including the analysis of organovolatile compounds by CPG/MS (including methanethiol) as well as a measurement of the degree of hydrolysis.

[0156] A mass balance of recovery of the protein floc obtained using the strains recommended for the invention (in bold) is also carried out. This is calculated from 1) the quantity of dry matter used in the crude extract and 2) the quantity of dry matter obtained in the floc. The ratio of the two (2/1) makes it possible to obtain an extraction yield. We compare example 4 (acidification with HCL). Table 3 below summarizes the results:

[Table 3]

Sd for standard deviation or “standard deviation” in English.

[0157] Example 6: Validation on an industrial pre-pilot scale of the invention

[0158] To facilitate the implementation of these tests but also to ensure a strict comparison of the scenarios, the chosen raw material is produced according to the same operating mode as the process head described in Example 1, then atomized in order to stabilize it.

[0159] Table 4: Physico-chemical characteristics of the atomized crude extract

[Table 4]

[0160] Four comparative tests and their associated prototypes are described Error!

Reference source not found.. They were conducted according to the following procedure:

- Rehydration of the raw extract atomized at 6% M.S.

- Acidification in a 20I Biolaffite fermenter:

. For the three “fermentation” tests, the reaction process is that described in paragraph 130 but adapted to a volume of 20 liters.

. For the “HCl” control, introduction of HCl to correct the pH to 5

- The different acidifications are followed by a heating step intended to precipitate the proteins still potentially in solution:

. Continuous: tubular exchange zone with parameters: preheating 35°C. chambering 74°C for 10 seconds - cooling 65°C

Batch: reaction tank with controlled heating and stirring - 60°C - 30 min

- Post-treatment of the must:

. Centrifugation 4000G

. Sediment recovery

. Redispersion with water for suspension 15% MS

. pH7 rectification

. HTST treatment (preheat 50°C / heat 130°C 2s / flash 75°C)

. Atomization (air inlet T°C = 200°C / air outlet T°C = 90°C)

[0161] Table 5 below summarizes the different tests: [0162] [Table 5]

[0163] The idea here is to validate that the process according to the invention works at a pre-pilot stage of 20 liters and the effect of a combination with heating making it possible to increase the precipitation yield. [0164] Biochemical and physicochemical analyzes are carried out which are summarized in Table 6 below:

[0165] [Table s]

[0166] It is interesting compared to the article by Emkani et al, 2021 (Emkani et al., Foods, 10, 549, 2021) to note that by practicing the process according to the invention, the degree of hydrolysis is unchanged. There is therefore no hydrolysis and the product is thus intact, unchanged from this point of view unlike Emkani et al, 2021 (Emkani et al., Foods, 10, 549, 2021). This point is particularly important when additional extrusion steps are carried out. Indeed, an extrusion step carried out on a hydrolyzed protein works less well.

[0167] Example 5: Characterization of the orqanovolatile composition of the samples generated: [0168] An analysis is carried out by GC/MS on several samples generated above in order to determine the different organovolatile compounds.

We compare “Samples 1” (according to the invention) and “Samples 4” (prior art control – HCl acidification). The results are presented in Table 7: [0169] [Table 7]

[0170] It is easily seen that the process according to the invention reduces by at least 75% all organovolatile compounds with the exception of methylacetate (whose content is unchanged) and ethylacetate (whose concentration is tripled ) in comparison to the prior art. In particular, the methanethiol content is reduced (around 15% of the prior art value). Methanethiol is a compound that has a fairly low concentration, of the order of ppb, generates sulfur flavors in food products such as ready-to-drink drinks or wet protein extrudates.

[0171] A precise quantification of methanethiol is carried out using the following protocol:

- After addition of internal standards (hexanal-d12 and dimethylsufide-d6), an aliquot of each sample was diluted in water and then subjected to solid phase micro-extraction (SPME). Desorption was carried out in the chromatograph injector. - The analyzes were carried out by coupling gas phase chromatography - mass spectrometry (GC-MS) according to the following operating conditions: o Chromatograph: Shimadzu 2010 o Chromatographic column: PDMS o Injection: Splitless / Split o Mass spectrometer: Shimadzu QP2010+ o Ionization method: Electronic impact (70 eV) o Detection mode: Scan

- The identification and quantification of hexanal and methanethiol are based on a 1-point calibration with these same reference compounds.

[0172] The results obtained are as follows:

[0173] We note that by practicing the invention, the hexanal content is two times lower compared to the prior art.

[0174] The methanethiol is also less than 100 μg/kg, a much higher value when practicing precipitation by adding acid as practiced in the prior art.

Claims

Claims [Claim 1] Process for extracting plant proteins comprising the following steps: 1. suspending a vegetable flour in a preferably aqueous solvent, so as to obtain a suspension of vegetable flour; 2a. adding a strain to the vegetable flour suspension of step 1, the strain being selected from the group consisting of Lactobacillus Fermentum, Lactobacillus Salivarius, Lactobacillus Delbrueckii subsp Jakobsenii, Lactobacillus Mucosae, Streptococcus Salivarius, and Enterococcus Lactis; the Lactobacillus strain being preferentially a Lactobacillus Fermentum strain; even more preferably the strain deposited with the CNCM under the number CNCM I-5802, so as to form a seeded suspension; 2b. incubating the inoculated suspension from step 2a so that the strain acidifies the inoculated suspension until a protein precipitate is formed; 3. Separation of the protein precipitate obtained at the end of step 2b. [Claim 2] Method according to claim 1 characterized in that the vegetable flour of step 1 is in the form of a vegetable powder containing a quantity of protein greater than 1% by weight, preferably between 15% and 30% in weight, relative to the weight of powder. [Claim 3] Method according to any one of claims 1 or 2 characterized in that the vegetable flour of step 1 is an isolate or a concentrate, preferably an isolate whose protein content is greater than 80% by dry weight on isolate dry matter. [Claim 4] Method according to any one of claims 1 to 3 characterized in that the vegetable flour of step 1 is a legume flour, preferably in that the vegetable flour is a legume flour selected from the group consisting of by peas and fava beans, more preferably in that the vegetable flour is pea flour. [Claim 5] Method according to any one of claims 1 to 4 characterized in that the incubation temperature of the suspension of step 2b is between 30°C and 50°C, preferably between 35°C and 45°C. °C. [Claim 6] Method according to any one of claims 1 to 5 characterized in that the pH of the vegetable flour suspension from step 1 is rectified so as to be between 6.5 and 7.5; preferably so as to be equal to 7.0, before the implementation of step 2a. [Claim 7] Method according to any one of claims 1 to 6 characterized in that the addition of strain of step 2a is carried out so as to obtain a seeded suspension having a strain concentration of said Lactobacillus of between 0.1.10 ⁹ and 1.10 ⁹ Colonies Forming Unit (CFU) per milliliter of vegetable flour suspension. [Claim 8] Method according to any one of claims 1 to 7 characterized in that the incubation of step 2b is carried out until the inoculated suspension has a pH between 4 and 5, preferably a pH of 5 ,0. [Claim 9] Method according to any one of claims 1 to 8 characterized in that if at the end of step 2b, the pH of the inoculated suspension is not between 4 and 5, step 2b comprises at the end of step 2b a sub-step 2b' of acidification of the seeded suspension by adding acid, so that the seeded suspension obtained at the end of step 2b has a pH of between 4 and 5, preferably between 5 and 4.5. [Claim 10] Method according to any one of claims 1 to 9 characterized in that step 2b comprises at the end of step 2b a sub-step 2b” of additional heating to increase the flocculation yield, consisting of bringing the vegetable flour suspension from step 2b at a temperature between 45° and 85°C. [Claim 11] Method according to any one of claims 1 to 10 characterized in that step 3 comprises the following steps: 3a. rectifying the pH of the inoculated suspension obtained at the end of step 2b to a pH between 6 and 9, preferably a pH of 7, preferably by adding soda or lime to said suspension; 3b. heat treatment of the suspension from step 3a between 100°C and 160°C for 0.1 to 1 s, and 3c. drying the vegetable flour suspension from step 3b until obtaining a vegetable flour isolate having a dry matter greater than 95% using an atomizer. [Claim 12] Plant protein isolate capable of being obtained by the process of any one of claims 1 to 11. [Claim 13] Plant protein isolate according to claim 12 characterized in that its degree of hydrolysis (or DH) is less than 10%, preferably less than 5. [Claim 14] Plant protein isolate according to any one of claims 12 or 13 characterized in that the methanethiol content is reduced by more than 25%, preferably by more than 50%, compared to an isolate obtained by acidification of a suspension of vegetable flour only by adding hydrochloric acid. [Claim 15] Plant protein isolate according to any one of claims 12 to 14 characterized in that its protein content is between 80% and 95% by weight, preferably between 82% and 92% by weight, preferably between 84%. and 90% by weight, preferably between 84% and 88% by weight, relative to the weight of total dry matter of the isolate. [Claim 16] Plant protein isolate characterized in that its hexanal content is less than 6000 μg/kg and its methanethiol content is less than 100 μg/kg. [Claim 17] Plant protein isolate according to claim 16 characterized in that the hexanal content is less than 5500 μg/kg, preferably less than 5000 μg/kg, preferably less than 4500 μg/kg, preferably 4000 μg/kg, preferably 3500 μg/kg. [Claim 18] Plant protein isolate according to claims 16 or 17 characterized in that the methanethiol content is less than 120 μg/kg, preferably less than 110 μg/kg, preferably less than 100 μg/kg, preferably less than 90 μg/kg, preferably 80 μg/kg, preferably 70 μg/kg, preferably 65 μg/kg. [Claim 19] Use of the isolate according to any one of claims 12 to 18 or obtained according to any one of claims 1 to 11 for industrial applications including food, nutraceutical and pharmaceutical applications. [Claim 20] Microbial strain deposited with the CNCM under number CNCM I-5802.