METHOD FOR PREPARING NUTRIENTS FROM INSECTS

Description

Technical Field

[0001] The invention relates to a process for preparing nutrients from insects. The prepared nutrients can be used in industry, particularly in the food industry and in animal feed. Previous technique

[0002] Insects provide a rich source of essential nutrients and are therefore a valuable food source. The European Union has even included them in its 2015 / 2283 regulation as a novel food, considering them a food of the future. This alternative diet is particularly relevant given the agricultural and environmental challenges facing populations and the increasing scarcity of land. Furthermore, since the nutrients obtained from insects are rich in protein and fat, their use could replace fish- or soy-based feed in animal nutrition.

[0003] Therefore, it has become essential to develop processes for preparing nutrients from insects, particularly on an industrial scale. Document WO 2016 / 108034 describes a process for preparing chitin and / or chitosan from insects by treating insect cuticles with an oxidizing agent and enzymatically hydrolyzing the cuticles with a proteolytic enzyme. However, this process requires the addition of an additive and does not allow for adequate fractionation of the insects, particularly to obtain a protein-enriched fraction.

[0004] Application WO 2013 / 191548 describes a process for converting insects or worms into nutrient streams to obtain three different fractions by enzymatic hydrolysis followed by separation. However, a significant loss of material remains, resulting in a decrease in the final yield, particularly of the protein fraction. Furthermore, the purity of the resulting fractions is not optimal.

[0005] Application FR 3 031 113 describes a process for producing product(s) of interest from insects, comprising a preliminary step of pressing insect cuticles to separate the press juice (containing, in particular, the oil fraction and the protein fraction) from the press cake (containing, in particular, chitin), followed by an enzymatic hydrolysis step of the press cake. This process, which is primarily aimed at extracting chitin and / or chitosan, is not optimized for obtaining sufficiently pure protein and oil fractions with a satisfactory yield.

[0006] Therefore, there is a need to develop a process for preparing nutrients from insects with a higher yield, particularly of the protein fraction. Furthermore, there remains a need to obtain purer nutrient fractions, especially a purer protein fraction, meaning one that is higher in protein and lower in fat.

[0007] It is in this context that the applicant has developed, and this constitutes the basis of the present invention, a process for preparing nutrients from insects comprising the steps described below. Summary of the invention

[0008] The present invention, which has applications in the field of food, aims to propose a new process for preparing nutrients from insects.

[0009] The invention relates to a process for preparing nutrients from insects comprising the following steps: a) grind insects to obtain a powder, b) subject the powder to enzymatic hydrolysis to obtain a hydrolyzed powder, c) press the hydrolyzed powder to obtain a solid fraction enriched in chitin and a liquid fraction, and d) subject the liquid fraction to physical separation to obtain an aqueous protein fraction and an oily fraction. Detailed description

[0010] The term "nutrients" refers to organic and / or inorganic compounds necessary for a living organism to function properly. In the context of the present invention, the fractions obtained by implementing the process according to the invention are considered to be "nutrients" or "nutrient fractions".

[0011] The term "insects" refers to insects at any stage of their development, such as the adult, larval, and / or pupal stage. In the context of the present invention, the insects are preferably in the larval stage. More specifically, the insects may be selected from Coleoptera, Diptera, Lepidoptera, Orthoptera, Isoptera, Hymenoptera, Blattodea, Hemyptera, Heteroptera, Ephemeroptera, and Mecoptera, preferably from Diptera. Preferably, the insects are selected from Tenebrio molitor, Hermetia illucens, Galleria mellonella, Alphitobius diaperinus, Zophobas morio, Blattera fusca, Tribolium castaneum, Rhynchophorus ferrugineus, Musca domestica, Chrysomya megacephala, Locusta migratoria, Schistocerca gregaria, Acheta domesticus, Gryllodes sigillatus, Gryllus assimillis And Samia Ricini, preferably chosen from Hermetia illucens, gryllodes sigillatus, Gryllus assimillis, Musca domestica, Tenebrio molitor, Alphitobius diaperinus And Achata domesticus. The larvae of Hermetia illucens are particularly preferred in the context of the present invention.

[0012] The present invention arises from the advantages demonstrated by the inventors of implementing the process for preparing nutrients from insects described below. For the purposes of this description, the terms "process for preparing nutrients from insects" and "process for preparing nutrient fractions from insects" are interchangeable.

[0013] The invention relates to a process for preparing nutrients from insects comprising the following steps: a) grind insects to obtain a powder, b) subject the powder to enzymatic hydrolysis to obtain a hydrolyzed powder, c) press the hydrolyzed powder to obtain a solid fraction enriched in chitin and a liquid fraction, and d) subject the liquid fraction to physical separation to obtain an aqueous protein fraction and an oily fraction.

[0014] The process according to the invention makes it possible in particular to obtain purer nutrient fractions and / or with a better yield, in particular a purer aqueous protein fraction, namely rich in proteins and poor in lipids. Step a)

[0015] Step a) consists of grinding the insects to obtain a powder. Grinding produces a starting material with a viscous consistency. The viscosity of the powder can vary depending on the nature and composition of the insects ground. A person skilled in the art will have no difficulty adjusting the viscosity of the powder. For example, the desired viscosity can be easily achieved by adding more or less water before, during, or after grinding the insects.

[0016] Grinding can be carried out with a suitable grinding tool, for example, a grinder with a turbine and cutting head, a ball mill, or a micro-grinder. The choice of grinding tool can influence the particle size of the insects present in the ground material. Preferably, the particle size of the insects in the ground material obtained in step a) is less than 2.0 mm, specifically less than 1.0 mm or even less than 0.5 mm. The particle size can be measured by any appropriate method, for example, by sieving. A person skilled in the art will have no difficulty adapting the grinding step to obtain the desired particle size. In general, the smaller the particle size, the easier the hydrolysis in step b). A small particle size promotes enzymatic attack and thus increases the efficiency of enzymatic hydrolysis.

[0017] In one particular embodiment, step a) is carried out at a temperature ranging from 20 to 90 °C, preferably from 40 to 70 °C.

[0018] The process according to the invention is particularly advantageous because it can be implemented on an industrial scale. Thus, the invention relates to an industrial process for preparing nutrients from insects. In a particular embodiment, step a) consists of grinding at least 25 kg of insects, at least 100 kg, at least 200 kg, at least 300 kg, at least 500 kg, at least 1000 kg, at least 2500 kg, at least 5000 kg, at least 7500 kg, for example at least 10,000 kg of insects. In particular, step a) consists of grinding at least 25 kg / h of insects, at least 100 kg / h, at least 200 kg / h, at least 300 kg / h, at least 500 kg / h, at least 1000 kg / h, at least 2500 kg / h, at least 5000 kg / h, at least 7500 kg / h, for example at least 10,000 kg / h of insects. Step b)

[0019] Step b) consists of subjecting the homogenate to enzymatic hydrolysis to obtain a hydrolyzed homogenate. This step notably solubilizes the proteins.

[0020] Some processes described in the prior art include a step of removing the oily fraction from the ground material before the enzymatic hydrolysis step (see, for example, the process described in FR 3 031 113). In the present invention, unlike what is described in the prior art, the ground material obtained in step a) does not undergo any separation step before the enzymatic hydrolysis step, such as a pressing step. The inventors have thus shown that it is not necessary to remove the oily fraction from the ground material before enzymatic hydrolysis and that the yield and purity of the aqueous and oily protein fractions are even improved.

[0021] In one particular embodiment, the process according to the invention does not include the addition of an oxidizing agent before the enzymatic hydrolysis step.

[0022] Step b) is carried out by contacting the ground material obtained in step a) with one or more protease enzymes. The protease(s) may be acidic, basic or neutral protease(s), for example chosen from aminopeptidases, metallocarboxypeptidases, serine endopeptidases, cysteine ​​endopeptidases, aspartic endopeptidases, metalloendopeptidases, exopeptidases or a mixture thereof.

[0023] The following enzymes, or a mixture of several of these enzymes, may be used in step b): Bacillus protease: Protamex (EC 3.4.21.14, Novozyme), Casein protease: Promod 439L (Biocatalysts), Aminopeptidases: Flavourzyme (EC 3.4.11.1, Novozyme), Fungal protease 500 (EC 3.4.11.1, Bio-Cat), Kojizyme (EC 3.4.11.1, Novozyme), Serine endopeptidases: Protex P (EC 3.4.21, Genencor International BV), Chymotrypsin (EC 3.4.21.1 Novozyme), Protamex (EC 3.4.21, Novozyme), Elastase (EC 3.4.21.14, Novozyme), Trypsin (EC 3.4.21.36, Novozyme), Alcalase (EC 3.4.21.4, Novozyme), Cysteine ​​endopeptidases: Papain (EC 3.4.22, BSC Biochemicals), Bromelain (ananase) (EC 3.4.22.32, Bio-Cat), Aspartic endopeptidases: Prolyve NP (EC 3.4.23, Lyven), Pepsin (EC 3.4.24.1, Sigma Aldrich), Metallo-endopeptidases: Neutral protease (EC 3.4.24.28, Bio-Cat), Endopeptidases: Protex 50 FP (EC 3.4.21, Genencor International BV (Dupont)), Sumizyme BNP-L (Takabio-Shin Nihon), Exo and endopeptidase (protease + amylase cocktail): Pancrealyve (Lyven), Aspartic protease: Izyme BA (EC 3.4.23, Novozyme), Aspergillopepsin l: Sumizyme AP-L (Takabio-Shin Nihon), Endoprotease based on Zn of beta ayloliequefaciens: Neutrase (EC 3.4.24, Novozyme), and Protease: Novozyme 37071 (Novozyme). .

[0024] The amount of enzyme(s) added in step b) can be easily adjusted according to the enzyme(s) used in order to obtain satisfactory enzymatic activity.

[0025] The pH of the homogenate can be adjusted depending on the enzyme(s) used. For acidic proteases, the pH will be acidic, generally ranging from pH 3 to pH 6. For alkaline proteases, the pH will be basic, generally ranging from pH 8 to pH 10. For neutral proteases, the pH will be neutral, generally ranging from pH 6 to pH 8.

[0026] The temperature during step b) can be adjusted depending on the enzyme or enzymes used and the desired reaction rate. In one particular embodiment, step b) is carried out at a temperature ranging from 40 to 70 °C, for example, from 50 to 55 °C.

[0027] Preferably, step b) is carried out under agitation, for example by placing the ground material in a tank equipped with an agitation device. Agitation can be facilitated by adding water to the mixture, which reduces viscosity, and / or by using a centrifugal pump. Agitation homogenizes the mixture and promotes enzymatic hydrolysis, thereby reducing hydrolysis time.

[0028] In one particular embodiment, the hydrolysis reaction is stopped by heating the hydrolyzed ground material, specifically at a temperature of 70 to 100°C, for example, by heating it to 80°C. Heating inactivates the protease. Generally, hydrolysis is stopped after 1 to 5 hours, for example, after 3 to 4 hours.

[0029] In another specific embodiment, the hydrolyzed ground material is not heated to stop the hydrolysis reaction before step c) of pressing. Not heating the hydrolyzed ground material prevents its degradation by heat, particularly of the lipids it contains. This embodiment helps preserve the quality of the fractions obtained in step d), especially the oily fraction. Step c)

[0030] Step c) consists of pressing the hydrolyzed ground material to obtain a chitin-enriched solid fraction and a liquid fraction. The chitin-enriched solid fraction is commonly referred to as "press cake" or "mud," and the liquid fraction is commonly referred to as "press juice" or "filtrate." Pressing can be carried out using a suitable pressing tool, such as a screw press.

[0031] The pressing temperature must be high enough to liquefy the lipids in the hydrolyzed ground material (oil fraction). The pressing temperature is generally above 25°C, for example, between 25°C and 100°C, between 40°C and 100°C, between 60°C and 100°C, or between 80°C and 90°C. The temperature may depend on the nature of the lipids present in the hydrolyzed ground material.

[0032] Advantageously, the pressing tool is equipped with a sieve. The sieve retains the chitin-enriched solid fraction while allowing the liquid fraction to pass through. The pore size is preferably less than 3 mm, for example, 0.5 to 2 mm.

[0033] When pressing is carried out with a screw press equipped with a sieve, a person skilled in the art has no difficulty selecting a suitable sieve and adjusting the pressure, for example by adjusting the screw speed and the closure of the gate. Generally, the pressure applied with a screw press ranges from 1 to 5 bar. The use of a screw press is particularly advantageous because it allows for the efficient separation of the chitin-enriched solid fraction from the liquid fraction at a low rotational speed (less than 50 rpm) compared to the rotational speed of decanters (generally between 3000 and 4000 rpm), thus preventing the formation of an emulsion.

[0034] Unlike the processes described in the prior art, the process according to the invention does not require any other pressing step than step c). Thus, step c) is advantageously the only pressing step of the process.

[0035] Step c) makes it possible to obtain a press juice essentially free of solid elements, in particular essentially free of chitin. Pressing considerably facilitates the implementation of subsequent steps carried out using the press juice. The Applicant has indeed shown that the addition of a pressing step makes it possible to obtain particularly pure nutrient fractions, in particular an aqueous protein fraction rich in protein and low in lipids in step d).

[0036] The Applicant also demonstrated that the pressing step allows for a physical separation step (step d) to be carried out at lower temperatures than those described in the prior art, for example, at temperatures ranging from 50°C to 80°C, and in particular from 65°C to 75°C. Such a temperature helps preserve the liquid fraction during physical separation, including the quality of the oil fraction obtained in step d). This temperature also limits lipid oxidation, which further helps preserve the quality of the oil fraction obtained in step d).

[0037] The chitin content in the chitin-enriched solid fraction is preferably at least 1.5 times greater than the chitin content of the ground material, preferably at least twice greater, for example at least 2.5 or 3 times greater. Advantageously, the chitin content is at least 15% by mass of the dry mass of the chitin-enriched solid fraction, for example at least 20%, at least 25%, or at least 30%.

[0038] The solid fraction enriched in chitin can be used as is or transformed, for example to extract the chitin.

[0039] Chitin has numerous applications, particularly in the food industry as a thickening or stabilizing additive. Chitin can also be used in the pharmaceutical industry and in animal feed.

[0040] In the context of the present invention, the liquid fraction is transformed in step d) to obtain in particular aqueous and oily protein fractions, which are particularly valuable industrially, especially in animal feed. Step d)

[0041] Step d) involves subjecting the liquid fraction to physical separation to obtain an aqueous protein fraction and an oily fraction. Physical separation can be achieved by decantation, centrifugation, reverse osmosis, ultrafiltration, supercritical CO2 extraction, or a combination of several of these separation methods.

[0042] In a preferred embodiment, the physical separation is carried out using equipment that allows simultaneous centrifugation and decantation, for example, a plate separator or a three-phase decanter. Such equipment is commonly used in the food industry to obtain, in a single step, an aqueous fraction (e.g., an aqueous protein fraction) and an oily fraction. Both fractions are free of solid residues.

[0043] Three-phase decanters, also known as three-phase clarifiers, are used for the simultaneous separation of two liquid phases of different densities and a solid phase. Three-phase clarifiers thus perform a three-phase separation (solid-liquid-liquid separation) of dispersions of solid residues and two immiscible liquids of different densities (e.g., an oily fraction and an aqueous protein fraction). Several three-phase clarifiers are available on the market, such as the Flottweg Tricanter, the GEA, and the Andritz.

[0044] Plate separators are also known as clarifying separators or plate centrifuges. These are high-speed centrifuges used for clarifying suspensions and / or separating two liquids of different densities (e.g., an oily fraction and an aqueous protein fraction). They operate at higher speeds than three-phase decanters. Several plate separators are available on the market, such as the Flottweg plate separator, the GEA plate separator, and the Alfa Laval plate separator.

[0045] In one particular embodiment, step d) allows for the removal of solid residues present in the liquid fraction. In this particular embodiment, the liquid fraction is subjected to physical separation in order to obtain an aqueous protein fraction, an oily fraction, and a solid residue fraction (a fraction commonly referred to as "sludge" or "centrifuge sludge").

[0046] Step d) can be carried out at a temperature ranging from 45°C to 90°C. As explained above, step d) can be implemented at lower temperatures than those described in the prior art, for example at a temperature ranging from 50 to 80°C, in particular at a temperature ranging from 65 to 75°C.

[0047] In one particular embodiment, step d) is carried out with a plate separator at a temperature ranging from 50 to 80°C, for example from 65 to 75°C.

[0048] The oily fraction consists primarily of lipids contained in insects. This oily fraction can be filtered and / or clarified, notably by polishing or decantation. This step increases the purity of the oily fraction. The oily fraction can also be processed, for example, to extract specific compounds such as particular fatty acids.

[0049] The aqueous protein fraction mainly comprises the proteins contained in the insects that were hydrolyzed in step b).

[0050] Advantageously, the aqueous protein fraction obtainable by implementing the process according to the invention has a protein content (proteins, protein fragments, and free amino acids) of at least 60% by mass of the dry mass of said fraction, for example, at least 65%, 66%, 67%, 68%, 69%, 70%, 71%, 72%, 73%, 74%, or even more, by mass of the dry mass of said fraction. The aqueous protein fraction obtainable by implementing the process according to the invention may also have a protein content (proteins, protein fragments, and free amino acids) of at least 80% by mass of the dry mass of said fraction, for example, at least 81%, 82%, 83%, 84%, 85%, or even more, by mass of the dry mass of said fraction.

[0051] Advantageously, the aqueous protein fraction that can be obtained by implementing the process according to the invention has a lipid content of less than 20% by mass of the dry mass of said fraction, for example less than 15%, 14%, 13%, 12%, 10%, 9%, 8%, 7%, 6%, or even less than 5% by mass of the dry mass of said fraction.

[0052] In specific embodiments: (i) at least 20% by mass, preferably at least 25%, for example at least 30%, for example about 30%, of the proteins and protein fragments contained in the aqueous protein fraction have a molecular weight of less than 1300 Da; (ii) at least 20% by mass, preferably at least 30% by mass, even more preferably at least 40% by mass, for example at least 50% by mass, at least 60% by mass, for example about 70% by mass, of the proteins and protein fragments contained in the aqueous protein fraction have a molecular weight greater than 1300 Da; (iii) at least 20% by mass, for example at least 30% by mass, at least 40% by mass, at least 50% by mass, for example between 25% and 60% by mass, between 45% and 55% by mass, of the proteins and protein fragments contained in the aqueous protein fraction have a molecular weight between 1300 Da and 5700 Da;(iv) at least 5% by mass, for example at least 6%, at least 7%, at least 8%, at least 9%, at least 10% by mass, for example about 13% by mass, of the proteins and protein fragments contained in the aqueous protein fraction have a molecular weight greater than 10,000 Da; (v) the protein content (proteins, protein fragments and free amino acids) is at least 60% by mass of the dry mass of said fraction, for example at least 65%, 66%, 67%, 68%, 69%, 70%, 71%, 72%, 73%, 74%, for example at least 75%, 80%, 81%, 82%, 83%, 84%, 85%, or even more, by mass of the dry mass of said fraction; and / or (vi) the lipid content is less than 20% by mass of the dry mass of said fraction, for example less than 15%, 14%, 13%, 12%, 10%, 9%, 8%, 7%, 6%, or less than 5% by mass of the dry mass of said fraction. ;

[0053] Therefore, the aqueous protein fraction that can be obtained by implementing the process according to the invention can be characterized by one, two, three, four, five or six characteristics chosen from (i), (ii), (iii), (iv), (v) and (vi).

[0054] In a preferred embodiment, the aqueous protein fraction obtainable by implementing the process according to the invention is characterized by feature (iii) and one or more features selected from (i), (ii), (iv), (v), and (vi). A protein and protein fragment content of at least 20% in the aqueous protein fraction with a molecular weight between 1300 Da and 5700 Da is nutritionally advantageous and often corresponds to what nutritionists seek, for example, in the preparation of animal feed. Indeed, molecular weights below 1000 Da combined with a high proportion of free amino acids present drawbacks, with risks of diarrhea or malabsorption. Conversely, the highest molecular weights (e.g., above 7000 Daltons) are also less desirable in terms of digestibility and nutritional value.

[0055] In one particular embodiment, the proteins and protein fragments contained in the aqueous protein fraction have the molecular weight distribution of Table 6.

[0056] The aqueous protein fraction can also be dried to obtain a protein powder, for example, a protein powder containing less than 3% water by mass. In one particular embodiment, drying inactivates the protease, especially when the hydrolyzed powder is not heated to stop the hydrolysis reaction before step c). Drying methods are well described in the literature; examples include spray drying, vacuum drying, freeze-drying, and drum drying. The protein powder can be used as is, for example, in animal or human food, can be processed, for example, to extract amino acids or specific proteins, or can be incorporated into preparations intended for animal or human consumption. Optional steps

[0057] In a particular embodiment of the invention, the liquid fraction obtained in step c) is sieved before step d). Sieving removes any residual solid particles present in the liquid fraction. For example, sieving can be carried out with a sieve having a pore size of less than 1 mm, preferably less than 0.5 mm. Those skilled in the art may decide to add a sieving step if they consider that the liquid fraction contains too many residual solid particles.

[0058] In another particular embodiment of the invention, step a) is preceded by a step consisting of blanching the insects, for example by immersing them in water heated to over 80°C for a sufficient time. Immersion for 5 minutes in water at 90°C is generally sufficient. The larvae are then drained before step a) is carried out. This blanching step makes it possible, in particular, to clean the insects, especially the larvae, and to neutralize the enzymes naturally present in the insects. The enzymes naturally present in the insects can cause undesirable blackening, particularly during the preparation of the ground material in step a).

[0059] The optional steps mentioned above are not exhaustive and can be combined with each other.

[0060] The description also relates to, but is not part of the present invention, the following fractions:

[0061] An aqueous protein fraction obtainable by implementing the process according to the invention, wherein: (i) at least 20% by mass, preferably at least 25%, for example at least 30%, for example about 30%, of the proteins and protein fragments contained in said fraction have a molecular weight of less than 1300 Da; (ii) at least 20% by mass, preferably at least 30% by mass, even more preferably at least 40% by mass, for example at least 50% by mass, at least 60% by mass, for example about 70% by mass, of the proteins and protein fragments contained in the aqueous protein fraction have a molecular weight greater than 1300 Da; (iii) at least 20% by mass, for example at least 30% by mass, at least 40% by mass, at least 50% by mass, for example between 25% and 60% by mass, between 45% and 55% by mass, of the proteins and protein fragments contained in the aqueous protein fraction have a molecular weight between 1300 Da and 5700 Da;(iv) at least 5% by mass, for example at least 6%, at least 7%, at least 8%, at least 9%, at least 10% by mass, for example about 13% by mass, of the proteins and protein fragments contained in the aqueous protein fraction have a molecular weight greater than 10,000 Da; (v) the protein content (proteins, protein fragments and free amino acids) is at least 60% by mass of the dry mass of said fraction, for example at least 65%, 66%, 67%, 68%, 69%, 70%, 71%, 72%, 73%, 74%, for example at least 75%, 80%, 81%, 82%, 83%, 84%, 85%, or even more, by mass of the dry mass of said fraction; and / or (vi) the lipid content is less than 20% by mass of the dry mass of said fraction, for example less than 15%, 14%, 13%, 12%, 10%, 9%, 8%, 7%, 6%, or less than 5% by mass of the dry mass of said fraction.

[0062] Therefore, the aqueous protein fraction that can be obtained by implementing the process according to the invention can be characterized by one, two, three, four, five or six characteristics chosen from (i), (ii), (iii), (iv), (v) and (vi).

[0063] The aqueous protein fraction obtainable by implementing the process according to the invention can be characterized by characteristic (iii) and one or more characteristics selected from (i), (ii), (iv), (v), and (vi). A protein and protein fragment content of at least 20% in the aqueous protein fraction with a molecular weight between 1300 Da and 5700 Da is nutritionally advantageous and often corresponds to what nutritionists seek, for example, in the preparation of animal feed. Indeed, molecular weights below 1000 Da combined with a high proportion of free amino acids present drawbacks, with risks of diarrhea or malabsorption. Conversely, the highest molecular weights (e.g., above 7000 Daltons) are also less desirable in terms of digestibility and nutritional value.

[0064] The proteins and protein fragments contained in the aqueous protein fraction may have the molecular weight distribution of Table 6.

[0065] For example, but not limited to, the aqueous protein fraction that can be obtained by implementing the process according to the invention is characterized by: (iii) at least 20% by mass, for example at least 30% by mass, at least 40% by mass, at least 50% by mass, for example between 25% and 60% by mass, between 45% and 55% by mass, of the proteins and protein fragments contained in the aqueous protein fraction have a molecular weight between 1300 Da and 5700 Da; and (vi) the lipid content is less than 20% by mass of the dry mass of said fraction, for example less than 15%, 14%, 13%, 12%, 10%, 9%, 8%, 7%, 6%, or less than 5% by mass of the dry mass of said fraction.

[0066] An oily fraction that can be obtained by implementing the process according to the invention.

[0067] A solid fraction enriched in chitin capable of being obtained by implementing the process according to the invention, wherein the chitin content is at least equal to 15% by mass of the dry mass of said fraction, for example at least equal to 20%, at least equal to 25%, at least equal to 30%.

[0068] The characteristics of these three fractions are specified in steps c) and d) above.

[0069] The present invention is now illustrated by the following non-limiting examples. In these examples, and unless otherwise indicated, percentages are expressed relative to dry mass. Brief description of the drawings

[0070] [ Fig. 1[ ] represents a flowchart of the steps of a process according to the invention. The process includes, in particular, the steps of boiling the larvae, grinding, enzymatic hydrolysis, pressing, separation by a plate separator, and then drying the aqueous protein fraction, called "de-oiled hydrolysate" or "insect protein hydrolysate". This flowchart corresponds to Protocol 1.

[0071] [ Fig. 2 [ ] represents a flowchart of the steps of a process that is not according to the invention. The process includes, in particular, steps of boiling the larvae, grinding, enzymatic hydrolysis, and separation by centrifuge to obtain an aqueous protein fraction. The process does not include a pressing step. This flowchart corresponds to Protocol 2. EXAMPLE Materials and methods

[0072] Each content was measured on samples of each fraction using the following methods: Method for measuring protein content (proteins, protein fragments, and free amino acids): protein content was measured by determining the nitrogen content of the raw material (Kjeldahl method), then multiplying the nitrogen content by a coefficient of 6.38 to obtain the protein content of the raw material. The protein content of the raw material was then multiplied by the percentage of dry mass to obtain the protein content by mass of the dry mass.

[0073] Method for measuring the molecular weight of proteins and protein fragments: Aqueous protein fraction samples were passed through a gel filtration column in which the migration rate of molecules depends on their molecular weight: larger molecules migrate fastest, while smaller ones elute at the end of the analysis. The UV detector detected the elute proteins at 214 nm. The peak size is proportional to the amount of protein elute. The different hydrolysates could be compared by comparing the peak areas between given fixed times. Using standards (reference proteins with known molecular weights: ovalbumin, lysozyme, protinin, alpha-chain insulin, human angiotensin II, L-tryptophan), an equivalence of retention time as a function of molecular weight was determined.

[0074] Method of measuring lipid content: lipid content was measured by MGRA-H assay by a COFRAC accredited laboratory.

[0075] Method for measuring chitin content: Chitin content was measured by glucosamine assay using ion chromatography. The glucosamine content was then divided by a factor of 1.062 to obtain the chitin content.

[0076] Method for measuring mineral content: Mineral content was determined by measuring the total mass of the raw ash. A sample, placed in a crucible, was incinerated at 550°C in an electric muffle furnace with a thermostat. The residue was weighed. Protocol 1: Preparation of nutrients from insects - according to the invention

[0077] 165 kg of Black soldier fly larvae ( Hermetia illucens Live larvae were used in this protocol. The dry mass content and dry mass composition of a larval homogenate are presented in Table 1.

[0078] The larvae were placed on a cloth and then immersed in water at a temperature of 90°C for 5 minutes. The mass of the larvae after the blanching stage was approximately 196 kg, which corresponds to a water intake of 31 kg. Step a)

[0079] The bleached larvae were introduced into an Urschel Comitrol 1700 grinder and ground to obtain a medium particle size of 0.5 mm. The temperature of the ground material at the grinder outlet was approximately 40-45°C. Step b)

[0080] The ground material was then placed in a stirring tank with 0.4 kg of protease. The temperature was raised to 60 °C. The pH was set at 8. To facilitate stirring, water was added to the mixture during hydrolysis.

[0081] A centrifugal pump was also installed on the reactor to improve the agitation of the mixture.

[0082] After three hours of stirring, the temperature of the mixture was raised to 80°C to stop the enzymatic reaction. Step c)

[0083] The hydrolyzed ground material was then pressed using an Olexa MBU 75 wet screw press equipped with a 2 mm pore size sieve. The pressing temperature was 85°C. The press valve was set to be three-quarters closed.

[0084] A press cake corresponding to the solid fraction enriched in chitin (mass: 18 kg) and a press juice corresponding to the liquid fraction (mass: 223 kg) were thus obtained.

[0085] The analyses of the press cake and press juice are presented in Table 2. The yields of this step are presented in Table 4. Step d)

[0086] The liquid fraction, heated to approximately 75°C, was then placed in a GEA Westfalia SAOH type plate separator to obtain three fractions: An oily fraction, having a density of about 0.9; an aqueous protein fraction, having a density of about 1.0; and a solid residue fraction with a density of 1.1.

[0087] The aqueous protein fraction showed no fat ring after centrifugation of a sample, proving that the separation step was successful. Furthermore, it should be noted that no emulsification was observed with Protocol 1.

[0088] The analyses of the three fractions are presented in Table 3. The yields of this stage are presented in Table 4. Other steps

[0089] The protein-enriched aqueous fraction was then dried using a horizontal spray dryer. The aqueous protein fraction was atomized into microspheres by nozzles in a turbine that generates a high-density, small-sized, converging conical stream of hot air. The inlet temperature of the hot air was 200–210°C and the outlet temperature was 90–96°C.

[0090] A protein powder was thus obtained from the aqueous protein fraction. The powder contained 76.8% protein by mass. Protocol 2: Preparation of nutrients from insects - outside of invention

[0091] 0.507kg of Black soldier fly larvae ( Hermetia illucens ) live samples were used in this protocol.

[0092] The dry mass content and dry mass composition of a ground-up larvae are presented in Table 1.

[0093] The larvae were blanched by immersion in boiling water in a laboratory reactor for 5 minutes with very gentle agitation, then placed on a sieve to drain. The mass of the larvae after the blanching step was approximately 0.566 kg, which corresponds to a water intake of 59 g. Step a)

[0094] 194 g of water were added to the bleached larvae which were then ground in a laboratory grinder fitted with a knife for 1 minute. Step b)

[0095] 1.52 g of the same protease used in protocol 1 was added to the homogenate. The temperature was raised to 55 °C. The pH was 7.2. After four hours, the temperature of the mixture was raised to 90 °C for 5 minutes to stop the enzymatic reaction.

[0096] The hydrolyzed powder, heated to 90°C, was then placed in a jar and centrifuged for 8 minutes at 3000 G to obtain four fractions: An oily fraction, having a density of about 0.9 (45g); An emulsion, having a density of about 0.95 (58g); An aqueous protein fraction, having a density of about 1.0 (425g); and A solid residue fraction (223g).

[0097] It should be noted that an emulsion was observed with Protocol 2. This emulsion was separated from the oily fraction and the aqueous protein fraction for analysis. The analyses of the three fractions (oily, aqueous protein, and solid residues) are presented in Table 3. The yields for this step are presented in Table 5.

[0098] The aqueous protein fraction comprised 62.3% by mass of protein. Analysis of the fractions obtained by implementing Protocols 1 and 2

[0099] Table 1 below corresponds to the analysis of the ground material: percentage of dry mass and content of certain constituents by mass of the dry mass. [Table 1] Percentage of dry mass Minerals Chitin (1) Proteins (2) Lipids (3) Other (4) Protocol 1 33,7 % 6,1 % 8,5 % 35,1 % 48,3 % 2% Protocol 2 36,0 % 5,3 % - 45,9 % 48,8 % - (1) Chitin content was not measured in Protocol 2. (2) The protein content of the larvae in Protocol 1 is estimated from the total nitrogen content on a dry basis (6.1%) minus the nitrogen contained in chitin (0.6%, since chitin contains 6.89% nitrogen), resulting in 5.5% protein nitrogen (multiplied by 6.38), or 35.1% protein on a dry basis. Since chitin content was not measured in Protocol 2, the protein content was not corrected. It is therefore overestimated by approximately 10%. (3) Lipid content was directly measured in Protocol 1. In Protocol 2, lipid content was calculated by subtracting protein content from mineral content (100% - (% minerals + % protein)). The lipid content is probably slightly overestimated in protocol 2 (chitin not measured).(4) The “other” column corresponds to the difference between dry matter and the sum of minerals, chitin, proteins and fats in protocol 1.

[0100] Table 2 below corresponds to the analysis of the liquid fraction and chitin-rich solid fraction after pressing: percentage of dry mass and content of certain constituents by mass of the dry mass. [Table 2] Percentage of dry matter Minerals Chitin Proteins Lipids Other (by difference) Liquid fraction 22,6 % 4,3 % Not measured 35,3 % 57,6 % 2,8 % Chitin-enriched solid fraction 46,3 % 7,8 % 27,5 % 38,3 % 14,9 % 11,5 %

[0101] Table 3 corresponds to the analysis of the aqueous, oily and solid residue protein fractions: percentage of dry mass and content of certain constituents by mass of the dry mass. [Table 3] dry mass Minerals Chitin (1) Proteins (2) Lipids (3) Other (by difference) Fractions obtained according to Protocol 1 Aqueous protein fraction 10,5% 8,3% 0,4% 76,8% <4,8% 9,7-14,5% Oily fraction 64,7% 0,5% Not measured 1,1% 77,3% 21,0% Solid residue fraction 22,9% 4,3% 0,3% 29,3% 60,7% 6,6% Fractions obtained according to Protocol 2 Aqueous protein fraction 10,5% 7,4% Not measured 62,3% 30,4% - Oily fraction 98,0% 1,7% Not measured 0,7% 97,6% - Solid residue fraction 27,9% 4,7% Not measured 47,0% 49,0% - (1) Chitin content was not measured in protocol 2. (2) Protein content in protocol 2 is overestimated because the nitrogen from chitin was not subtracted. (3) For protocol 2, lipid content is calculated by subtracting the mineral content from the protein content (100% - (% minerals + % protein)).

[0102] Conclusion: The aqueous protein fraction obtained with Protocol 1 has a higher protein content than that obtained with Protocol 2 (76.8% vs. 62.3%). Furthermore, the aqueous protein fraction obtained with Protocol 1 has a significantly lower lipid content than that obtained with Protocol 2 (4.8% vs. 30.4%). These results demonstrate that the pressing step significantly increased the purity of the aqueous protein fraction and prevented emulsification during physical separation. Yields of Protocols 1 and 2

[0103] The yield of protocol 1 corresponds to table 4. [Table 4] Mass (kg) Dry mass (kg) Protein (kg) Lipids (kg) Minerals (kg) Chitin (kg) Other (kg) Raw material (larvae) 165 55,6 19,5 26,9 3,4 4,7 1,1 Cake 18 8,4 3,2 1,2 0,7 2,3 1,0 press (Chitin-enriched solid fraction) Press juice (Liquid fraction) 223 50,3 17,8 29,0 2,2 Not measured 1,4 Total 241,0 58,7 21,0 30,2 2,8 2,3 2,4 Aqueous protein fraction 143 15,0 11,5 <0,7 1,2 Not measured 1,5 Oily fraction 14,0 9,1 0,4 7,0 0,0 Not measured 1,9 Solid residue fraction 64,5 14,8 4,3 9,0 0,6 Not measured 0,8 Total 221,5 38,8 16,3 16,7 1,9 Not measured 4,2

[0104] The yield of protocol 2 corresponds to table 5. [Table 5] Mass (g) Dry mass (g) (protein kg) Lipids (g) Minerals (g) Chitin (g) Raw material (larvae) 507 182,7 83,8 90,7 9,8 Not measured Fraction of solid residue obtained after centrifugation 223 62,3 29,2 30,5 2,9 Not measured Aqueous protein fraction obtained after centrifugation 425 44,8 31,3 13,6 4,9 Not measured Oily fraction obtained after 45 44,1 0,3 43,1 0,8 Not measured centrifugation Emulsion obtained after centrifugation 58 Not measured Not measured Not measured Not measured Not measured Total 751 151,2 60,8 87,2 8,6 Not measured

[0105] The yield of protocol 2 corresponds to table 5. Analysis of the molecular weights (Da) of proteins and protein fragments from the aqueous protein fraction obtained according to Protocol 1

[0106] Table 6 below corresponds to the analysis of the molecular weights of proteins and protein fragments of the aqueous protein fraction obtained according to Protocol 1. [Table 6] Molecular weights (MW) in Da Percentage (%) MW > 14000 10,97% 14000 < MW > 10000 2,38% 10,000 < MW > 6500 4,86% 6500 < MW > 5700 2,39% 5700 < MW > 2500 24,92% 2500 < MW > 1300 24,94% 1300 < MW > 900 8,54% 900 < MW > 600 9,27% 600 < MW > 360 2,77% 360 < MW > 200 2,48% 200 < MW > 130 5,11% MW < 130 1,37%

[0107] ConclusionThe aqueous protein fraction obtained according to Protocol 1 contains 29.54% of proteins and protein fragments with a molecular weight less than 1300 Da relative to the total amount of proteins and protein fragments in the aqueous protein fraction. It also contains approximately 50% of proteins and protein fragments with a molecular weight between 1300 Da and 5700 Da, which is particularly interesting from a nutritional point of view.

Claims

1. A method for preparing nutrients from insects, comprising the following steps: a) grinding the insects so as to obtain a ground material, b) subjecting the ground material to enzymatic hydrolysis so as to obtain a hydrolyzed ground material, c) pressing the hydrolyzed ground material so as to obtain a chitin-enriched solid fraction and a liquid fraction, and d) subjecting the liquid fraction to a physical separation so as to obtain an aqueous protein fraction and an oil fraction.

2. The preparation method according to claim 1, wherein the insects are chosen from Tenebrio molitor, Hermetia illucens, Galleria mellonella, Alphitobius diaperinus, Zophobas morio, Blattera fusca, Tribolium castaneum, Rhynchophorus ferrugineus, Musca domestica, Chrysomya megacephala, Locusta migratoria, Schistocerca gregaria, Acheta domesticus, Gryllodes sigillatus, Gryllus assimillis and Samia ricini, preferably Hermetia illucens.

3. The preparation method according to any of the preceding claims, also comprising a step prior to step a), which consists in blanching the insects.

4. The preparation method according to any of the preceding claims, wherein step a) makes it possible to obtain a ground material with a particle size of less than 2.0 mm.

5. The preparation method according to any of the preceding claims, wherein the enzymatic hydrolysis of step b) is performed with one or more proteases.

6. The preparation method according to any of the preceding claims, in which step c) is performed with a screw press.

7. The preparation method according to any of the preceding claims, wherein step d) is performed with a disk-type separator.

8. The preparation method as claimed in claim 1, wherein step d) is performed at a temperature ranging from 50 to 80°C, for example from 65 to 75°C.

9. The preparation method according to any of the preceding claims, wherein the aqueous protein fraction is dried to obtain a protein powder.

10. The preparation method according to any of the preceding claims, wherein the oil fraction is filtered and / or clarified, preferably by polishing or by decantation.