RU2790403C2 - Method for treatment of insects, including separation of cuticle from soft part of insects, using belt separator, with subsequent separation of soft part into three fractions - Google Patents

Abstract

FIELD: fodder industry.

SUBSTANCE: invention relates to a method for treatment of insects, including separation of the cuticle from a soft part of insects, and then, separation of the soft part of insects into an oil fraction, a solid fraction, and an aqueous fraction, with subsequent use in animal feed. A method for treatment of insects for feed for obtainment of a solid fraction or an aqueous fraction is proposed, including following stages: killing of insects by scalding with hot water at a temperature of 87-100°C or blanching at a temperature of 80-105°C; separation of cuticles from a soft part of insects, using a tape belt filter press or a belt separator, where soft parts are muscles, internal organs, biological fluids, water, and hemolymph, and then, separation of the soft part of insects into an oil fraction, a solid fraction, and an aqueous fraction, where separation is carried out in two stages: at the first stage, using a two-phase decanter to obtain solid and liquid fractions, at the second stage, using a centrifuge for separation of the liquid fraction into oil and aqueous fractions, or separation is carried out directly into an aqueous fraction, a solid fraction, and an oil fraction, using a three-phase decanter. A solid fraction for feed is proposed, obtained from insects by the specified method, containing at least 71 wt.% of protein and from 0.1 to 2 wt.% of chitin, wherein weight percentages are indicated relatively to the total dry weight of the solid fraction, while at least 60% of soluble proteins have a size of less than 550 g/mol. An aqueous fraction for feed is proposed, obtained from insects by the specified method, containing at least 48 wt.% of protein, at least 2 wt.% of trehalose and having a lipid content of less than 7 wt.%, wherein weight percentages are indicated relatively to the total dry weight of the aqueous fraction. The use of the specified aqueous fraction for feed as a flavoring agent in animal feed is also proposed.

EFFECT: invention provides the production of high-quality protein feed for animals.

12 cl, 1 dwg, 6 tbl, 2 ex

Description

The present invention relates to a method for treating insects. The invention also relates to powders, in particular to a powder which can be obtained by the method of treating insects according to the invention, and to the use of these powders in nutrition, in particular in animal feed.

Powders derived from animals have long been used in animal nutrition.

One of the most widely used powders is fishmeal, which is one of the main sources of protein in animal feed. Fishmeal is very rich in animal protein (rich in amino acids such as lysine and methionine), which is easily digestible. Growing demand, accompanied by limited supply, has led, in particular, to a significant increase in the price of fishmeal. Thus, there is a high demand for alternative sources of high quality and, wherever possible, renewable protein that could be used in animal feed.

In recent years, it has been proposed to use insect meal as a substitute for fish meal.

Insect meal offers natural protein sources for replacement and the ability to be mass-produced with minimal environmental impact. In particular, some beetles such as Tenebrio molitor are of interest, as they are suitable for intensive mass production.

By way of example, WO2016/108037 describes in particular a beetle powder containing at least 67% by weight of protein and at least 5% by weight of chitin, which can be used in animal feed.

In the context of the present application, chitin is understood to mean any type of chitin derivative, i.e., a polysaccharide derivative containing N-acetylglucosamine units and D-glucosamine units, in particular chitin-polypeptide copolymers (sometimes referred to as chitin-polypeptide composites). These copolymers can also be combined with pigments, often of the melanin type.

Chitin was the second most synthesized polymer after cellulose in living nature. Indeed, chitin is synthesized by many species of the animal world: it forms part of the exoskeleton of crustaceans and insects and the side wall that surrounds and protects fungi. More specifically, in insects, chitin makes up 3 to 60% of their exoskeleton.

However, chitin is generally considered a compound that is difficult for some animals to digest.

Therefore, there is a need for insect-derived powders that have a reduced chitin content.

The work of the authors of the present invention made it possible to demonstrate that such powders can be obtained if the insects from which they are prepared are subjected to special processing.

Thus, the invention relates to a method for treating insects, comprising the following steps,

- separation of the cuticle from the soft part of the insects, and then

- separation of the soft part of insects into an oil fraction, a solid fraction and an aqueous fraction

By "insects" is meant insects at any stage of their development, ie the adult, larval or pupal stage.

The cuticle is the outer layer (or exoskeleton) secreted by the epidermis of insects. It usually consists of three layers: epicuticle, exocuticle and endocuticle.

The term "soft part" refers to the flesh (including but not limited to muscles and internal organs) and juices (including but not limited to body fluids, water and hemolymph) of insects. In particular, the soft part does not consist of insect juices.

Preferably, the insects used in the method according to the invention are in the larval stage.

Preferably, the insects used in the method according to the invention are edible.

Preferably, the insects preferred for carrying out the method of the invention are, for example, Coleoptera, Diptera, Lepidoptera, termites, Orthoptera, Hymenoptera, Cockroaches, Bedbugs, Oteropterans, Mayflies and Scorpion flies, of which Coleoptera, Diptera, Orthoptera, Lepidoptera or their mixtures, more preferably beetles.

Coleoptera preferably used in the method according to the invention belong to the families Tenebrionidae , Melolonthidae , Dermestidae , Coccinellidae , Cerambycidae , Carabidae , Buprestidae , Cetoniidae , Dryophthoridae or mixtures thereof.

More preferably we are talking about the following Coleoptera: Tenebrio molitor, Alphitobius diaperinus, Zophobas morio, Tenebrio obscurus, Tribolium castaneum and Rhynchophorus ferrugineus or mixtures thereof.

The oil fraction has a lipid content greater than or equal to 90%, preferably greater than or equal to 95%, even more preferably greater than or equal to 99% by weight of the total weight of the oil fraction.

Note that within the scope of this application, unless otherwise indicated, the indicated ranges of values include boundaries.

The solid fraction has a solids content of 45 to 65 wt.% of the total weight of the solid fraction.

The aqueous fraction has a carbohydrate content of 15 to 40% by weight, preferably 20 to 30% by weight, based on the total dry weight of the aqueous fraction.

After the step of separating the soft part and before the optional step of thickening it, the aqueous fraction has a solids content of less than or equal to 20% by weight, preferably less than or equal to 15% by weight of the total weight of the aqueous fraction.

In the first embodiment, the separation of the cuticles from the soft part of the insects is carried out using a filter press.

The filter press consists of a filter cloth and allows separation according to the pressure filtration principle.

In the second embodiment, the separation of the cuticles from the soft part of the insects is carried out using a belt separator.

A belt separator is understood as a device for separating the hard part from the soft part of the product, which contains a tension belt (or pressure belt) and a perforated drum.

The separation of the cuticle from the soft part of insects is described more broadly below in connection with step 2 of the detailed insect treatment method according to the invention.

This separation of the cuticle from the soft part of the insect makes it possible, in particular, to separate the chitin from the soft part. Indeed, as indicated below, the cuticle obtained from this separation step has a high content of chitin, on the order of 10-30% by weight of the total weight of the cuticle.

In particular, the step of separating the cuticle from the soft part is carried out without carrying out any preliminary step of grinding the insects, in particular in the form of particles.

Likewise, the separation of the soft part of insects into an oil fraction, a hard fraction and an aqueous fraction is described more broadly below in connection with step 4 of the detailed method for treating insects according to the invention.

The method of treating insects according to the invention may include a killing step prior to the step of separating the cuticle from the soft part.

Preferably, after killing step 1, the insects are directly used to carry out step 2 of cutting off the cuticle from the soft part of the insects, i.e. the insects are not subjected to any processing such as grinding, freezing or dehydration between step 1 and step 2.

This killing step is described more broadly below in connection with step 1 of the detailed method for treating insects according to the invention.

Optionally, the insect treatment method of the invention further comprises the step of thickening the water fraction between the step of separating the cuticle from the soft portion and the step of separating the soft portion into an oil fraction, a hard fraction and an aqueous fraction.

By the "maturation step" of the soft part of the insects is more specifically understood the step in which the soft part of the insects is subjected to agitation.

This step is described more broadly below in connection with step 3 of the detailed method for treating insects according to the invention.

The method for treating insects according to the invention may optionally include the step of thickening the aqueous fraction to obtain a concentrated aqueous fraction.

This step is described more broadly below in connection with step 5 of the detailed method for treating insects according to the invention.

In addition, the method for treating insects according to the invention optionally includes the step of mixing the solids:

- with all or part of the concentrated aqueous fraction; and/or

- with all or part of the cuticle,

to get a mixture.

This step is described more broadly below in connection with step 6 of the detailed method for treating insects according to the invention.

Preferably, the method of treating insects according to the invention includes the step of drying the solid or mixture to obtain a dry solid or dry mixture, respectively.

This step is described more broadly below in connection with step 7 of the detailed method for treating insects according to the invention.

Preferably, the insect treatment method according to the invention further comprises the step of grinding the dry solids or dry mixture.

According to one preferred embodiment of the method for treating insects according to the invention, it is a method for obtaining a powder, in particular an insect powder, and comprises the following steps:

i) killing insects;

ii) separating the cuticle from the soft part of the insects;

iii) optionally, maturation of the soft part of the insects;

iv) separating the soft part of the insects into a solid fraction, an aqueous fraction and an oil fraction;

v) optionally, thickening the aqueous fraction to obtain a concentrated aqueous fraction;

vi) optionally, mixing the concentrated aqueous fraction and/or cuticle with a solid fraction to obtain a mixture;

vii) drying the solid fraction obtained in step iv) or the mixture obtained in step vi) to obtain a dry solid fraction or dry mixture; And

viii) grinding the dry solids or dry mixture obtained in step vii).

Detailed description of the insect treatment method according to the invention

Stage 1: Killing insects

The killing step 1 can be advantageously carried out by thermal shock, for example by scalding or blanching. This stage 1 allows insects to be killed while reducing the microbial load (reducing the risk of damage and hygiene risks) and inactivating internal insect enzymes that can cause autolysis and thus their rapid browning.

Thus, for scalding insects, preferably larvae, soak in hot water for 2-20 minutes, preferably 5-15 minutes. Preferably, the water has a temperature of 87°C to 100°C, preferably 92°C to 95°C.

The amount of water introduced during scalding is determined as follows: the ratio of the volume of water in ml to the weight of insects in g is preferably 0.3 to 10, more preferably 0.5 to 5, even more preferably 0.7 to 3, and more more preferably on the order of 1.

For blanching insects, preferably larvae, are blanched in water or steamed (heads or steam bed) at a temperature in the range of 80-105°C, preferably 87-105°C, more preferably 95-100°C, even more preferably 98°C alternatively with water at 90-100°C, preferably 92-95°C (using spray nozzles) or in mixed mode (water+steam) at 80°C to 130°C, preferably 90°C to 120°C C, more preferably from 95°C to 105°C, even more preferably at 98°C. When the insects are blanched with steam alone, the blanching is preferably carried out in forced steaming steam blanchers. The residence time in the blanching chamber is 5 seconds to 15 minutes, preferably 1 to 7 minutes.

Preferably, after step 1, killing the insects is directly used to carry out step 2 of cutting off the cuticle from the soft part of the insects, that is, between step 1 and steps 2, the insects are not subjected to any treatment such as grinding, freezing or dehydration.

Stage 2: Separation of the cuticle from the soft part of the insects

The purpose of the stage is to separate the cuticle from the soft part of the insects.

The separation of the cuticle from the soft part of the insects can be accomplished with any suitable type of separator.

In the first embodiment, the separation of the cuticles from the soft part is carried out using a filter press.

Preferably, the filter press used in the insect treatment process of the invention is a belt filter press.

The belt filter press contains two perforated tension belts (also called filter cloth). The insects are placed between two perforated tension bands in such a way that under pressure the soft part of the insects passes through the perforations of the tension bands, and the hard part of the insects remains between the two perforated tension bands.

The person skilled in the art is able to determine the diameter of the perforations of the tension bands, as well as the pressure applied to separate the cuticles from the soft part of the insects.

Examples are belt filter presses (or belt presses) from Flottweg or belt filter presses from ATR Créations.

In the second embodiment, the separation of the cuticles from the soft part is carried out using a belt separator.

For example, the belt separator may comprise a tension belt and a perforated drum, the tension belt surrounding at least a portion of the perforated drum.

The tension tape allows insects to be delivered and applied to the perforated drum so that the soft part passes under pressure through the holes in the drum, while the hard part of the insects (cuticle) remains outside the drum.

The cuticles can then be collected with a scraper.

Examples include belt separators from Baader such as belt separators 601-607 (soft separator 601-607) or SEPAmatic® belt separators from BFD Corporation (range 410-4000V).

Preferably, the diameter of the holes in the drum is 0.5 to 3 mm, preferably 1 to 2 mm.

With regard to pressure, the specialist is able to independently determine the pressure exerted so that the cuticles can be separated from the soft part of the insects.

This step of separating insects into parts differs from classical pressing, which can be carried out, for example, using a single screw or twin screw press, in that it allows a clean separation of the soft part from the insect cuticle, but does not separate the juices from the hard fraction.

Preferably, the separation of the cuticles from the soft part of the insects is carried out using a belt separator.

The cuticles obtained in step 2 contain 10 to 30% by weight, preferably 15 to 25% by weight of chitin, based on the total dry weight of the cuticles.

The determination of the proportion of chitin is carried out by its extraction. For example, ADAC 991.43 can be used as a method for determining the proportion of chitin.

In addition, the cuticles contain less than 25%, preferably less than 10%, more preferably less than 5%, even more preferably less than 3 wt.% lipids based on the total dry weight of the cuticles.

Methods for determining the content of fats (lipids) are well known to the specialist. As a preferred example, the determination of their content can be carried out according to the method described in the regulation CE 152/2009.

In the entire application, when the date of a regulation, standard or directive is not indicated, it refers to the regulation, standard or directive in force on the date of filing of the application.

In addition, the cuticles contain 55-90%, preferably 60-85%, preferably 65-80% protein by weight of the total dry weight of the cuticles.

For the purposes of this application, protein refers to the amount of crude protein. Quantification of crude protein is well known to those skilled in the art. An example is the Dumas method or the Kjeldahl method. It is preferable to use the Kjeldahl method.

Note, however, that this method is based on the measurement of nitrogen content. However, chitin contains about 8% nitrogen. Therefore, the nitrogen content of chitin is subtracted from the measured nitrogen content before conversion is carried out to obtain the protein content.

The cuticles contain from 0.5 to 30 wt.%, preferably from 1 to 20 wt.%, preferably from 5 to 15 wt.% carbohydrates based on the total dry weight of the cuticles.

The carbohydrate content was calculated by measuring the difference in carbohydrates. According to this method, the carbohydrate content is equal to the dry matter content, from which the ash, protein and lipid content is subtracted.

In addition, the cuticles preferably contain at least 0.08 wt.%, more preferably at least 0.1 wt.%, even more preferably at least 0.12 wt.% trehalose based on the total dry weight of the cuticles.

The amount of trehalose is determined by GC-MS analysis. Such an analysis is described more broadly in Example 1 below.

The soft part obtained in step 2 contains from 20 to 50 wt.% lipids, preferably from 30 to 40 wt.% lipids based on the total dry weight of the soft part.

In addition, the soft part contains at least 45%, preferably at least 48%, more preferably at least 50% by weight of protein based on the total dry weight of the soft part.

Stage 3: Maturation of the soft part of insects

The soft part of the insects can then optionally be subjected to mixing in the tank.

Preferably, aging is carried out over a period of 15 minutes to 3 hours, preferably over 1 hour.

Preferably, the aging is carried out at a temperature of 65-100°C, preferably 85-100°C, more preferably at a temperature of about 90°C.

This step makes it easier to separate the soft part of the insects in the subsequent step 4.

The method according to the invention preferably includes this step.

In particular, no dilution of the soft part of the insects in a solvent such as water is required in this step.

Stage 4: Separation of the soft part into a solid fraction, an aqueous fraction and an oil fraction

The purpose of this stage is to collect three fractions, based on the soft part of the insects obtained in stage 2 or 3, namely, a solid fraction, an aqueous fraction and an oil fraction.

In the first embodiment, this step of separating the soft part is carried out in two steps.

In the first stage, the soft part of the insects is subjected to decantation in a two-phase decanter to obtain a solid fraction and a liquid fraction.

In the second stage, the liquid fraction is centrifuged to recover an oil fraction and an aqueous fraction.

In this second stage, it is preferable to use a plate centrifuge.

In the second embodiment of step 4, the soft part of the insects is decanted in a three-phase decanter to directly obtain an aqueous fraction, an oil fraction and a solid fraction.

Suitable three-phase decanters are, for example, Tricanter® from Flottweg or three-phase decanters from GEA, such as the CA 225-03-33 decanter.

It is preferable to carry out the separation of the soft part according to the second embodiment.

Indeed, the use of a three-phase decanter makes it possible to achieve a particularly effective phase separation. More specifically, the resulting solid fraction has a high solids content, the aqueous fraction contains little insoluble precipitates (derived from the solid fraction) and oil, and the oil fraction contains little insoluble precipitates (derived from the solid fraction) and water.

Stage 5: Thickening of the water fraction

The aqueous fraction obtained in step 4 can then optionally be thickened to obtain a concentrated aqueous fraction.

Preferably, thickening is carried out by evaporation.

Preferably, the evaporation is carried out at a temperature of from 30°C to 100°C, preferably from 60°C to 80°C.

Preferably, the evaporation is carried out at a pressure in the range from 50 to 1013 mbar, preferably at 1013 mbar.

Evaporation is preferably carried out over a period of 5 to 20 minutes.

The thickening is preferably carried out using a falling film evaporator, a rising film plate evaporator or a thin layer evaporator.

This type of standard equipment can be used without encountering the problem of fouling, thanks in part to the small amount of sediment present in the water fraction.

Generally, the aqueous fractions cannot be thickened to a solids concentration above 42%, as they tend to thicken (glue water) from this concentration.

In the present invention, the aqueous fraction contains a soluble protein of small size (as described in more detail below, at least 45% of the soluble protein of the aqueous fraction is less than 550 g/mol), which avoids thickening and thus allows to obtain an aqueous fraction with high solids concentration (up to 70%) and having a viscosity below 30,000 centipoise (centipoise).

By soluble protein, among crude proteins, is meant a protein which is soluble in an aqueous solution whose pH is between 6 and 8, preferably between 7.2 and 7.6.

When the term "protein" is used in this application, it refers to crude proteins.

Preferably, the aqueous solution is a buffer solution with a pH of 6 to 8, preferably 7.2 to 7.6. Preferably, the buffer solution is a NaCl phosphate buffer solution having a pH of 7.4±0.2.

In addition, the step of thickening the water fraction is beneficial in two respects, as it allows:

- save steam: in the absence of thickening stage 5, the water must be evaporated in drying stage 7, described below, using a dryer whose specific steam consumption is higher than that of the evaporator described above, and

- to avoid microbiological contamination due to the reduction in volume and osmotic pressure due to the high concentration of solids in the concentrated aqueous fraction.

Step 6: Mixing the concentrated aqueous fraction and/or cuticles with the solid fraction

All or part of the cuticles obtained in step 2 and/or all or part of the concentrated aqueous fraction obtained in step 5 may optionally be mixed with the solid fraction obtained in step 4 to obtain a mixture.

Preferably, the mixture is homogenized to facilitate its later processing.

Suitable mixers are, for example, conical screw mixers such as mixers from Vrieco-Nauta® or pendulum mixers such as mixers from PMS.

Note that, on average, 500 to 650 g of cuticles, for example about 550 g, and 250 to 350 g of water fraction, for example about 300 g, are obtained per kilogram of solids obtained.

Stage 7: Drying of the solid fraction obtained in stage 4 or the mixture obtained in stage 6

The solid fraction obtained in step 4, or the mixture obtained in step 6, can be dried to obtain a dry solid fraction or dry mixture.

Preferably, drying is carried out using a disc dryer, tube dryer, propeller dryer, flash dryer, thin film dryer or spray dryer.

Preferably, drying is carried out using a disc or tube dryer.

Suitable tube dryers are, for example, dryers from Tummers (Simon Dryers Technology).

Suitable disc dryers are, for example, dryers from Haarslev.

The drying time may be from 1 to 10 hours, preferably from 3 to 5 hours.

Preferably, drying is carried out at a temperature of from 60°C to 225°C, preferably from 80°C to 100°C.

Preferably, evaporation is carried out at atmospheric pressure.

Stage 8: Grinding of the dry solid fraction or dry mixture obtained in stage 7

After drying, grinding can be carried out and a powder can be obtained.

By powder is meant a composition in the form of particles.

Preferably, the powder according to the invention is an insect powder, i.e. a powder obtained exclusively from insects and optionally water.

A grinder such as a hammer mill or a cone crusher (such as Kemutec's "Kek cone mills" cone crushers) can be used.

Preferably, the milling output yields a particle size of less than 0.5 cm (the largest particle size that can be seen under a microscope), preferably on the order of 1 mm. More specifically, the particle size is from 300 µm to 1 mm, even more preferably from 500 to 800 µm.

When the powder is ground to a particle size acceptable for human or animal consumption, it can be called "flour", in particular, insect meal (English insect meal). Particle size suitable for human or animal consumption is understood to mean a particle size in the range of 100 µm to 1.5 mm, preferably 300 µm to 1 µm, more preferably 500 to 800 µm.

Depending on whether optional steps 5 and/or 6 are carried out, different powders can be obtained, namely:

- powder obtained only from the solid fraction (stage 6 is not carried out);

- a powder obtained from a mixture of the solid fraction and all or part of the cuticles;

- a powder obtained from a mixture of a solid fraction and all or part of the concentrated aqueous fraction;

- a powder obtained from a mixture of the solid fraction, all or part of the cuticles and all or part of the concentrated aqueous fraction.

The invention also relates to products obtained by the process according to the invention.

In addition, the invention relates to a solid fraction, which can be obtained by the method of processing insects according to the invention.

The invention also relates to a solid fraction containing at least 71 wt.% protein and from 0.1 to 2 wt.% chitin, and weight percentages are indicated based on the total dry weight of the solid fraction.

Preferably, the solids contains at least 73 wt.%, more preferably at least 74 wt.%, even more preferably at least 75 wt.% protein, and weight percentages are based on the total dry weight of the solids.

Preferably, the solid fraction contains from 0.5 to 1.7 wt.% chitin based on the total dry weight of the solid fraction.

Preferably, the solid fraction contains from 5 to 17 wt.% lipids, preferably from 10 to 15 wt.% lipids, based on the total dry weight of the solid fraction.

Preferably, the solid fraction contains from 1 to 10 wt.%, preferably from 2 to 6 wt.% ash, based on the total dry weight of the solid fraction.

The method for determining the ash content is well known to those skilled in the art. Preferably, the ash was determined in accordance with the regulation CE 152/2009 of 27-01-2009.

In addition, the solid fraction preferably contains from 5 to 15 wt.%, more preferably from 7 to 13 wt.% carbohydrates based on the total dry weight of the solid fraction.

More specifically, the solids preferably contains at least 0.2 wt.%, more preferably at least 0.3 wt.%, even more preferably at least 0.35 wt.% trehalose based on the total dry weight of the solids.

Meanwhile, the digestibility of protein by humans and animals is highly dependent on the size of the protein. In animal nutrition, it is customary to reduce the size of proteins in order to facilitate the digestion of food by animals. This reduction in the size of proteins is usually carried out by hydrolysis processes (eg enzymatic), which are particularly costly to implement.

The solid fraction contains soluble protein, which is sufficiently reduced in size to facilitate digestion by the animal.

Preferably at least 75%, preferably at least 80%, more preferably at least 85% of the soluble solids protein is less than or equal to 12400 g/mol.

More specifically, at least 55%, preferably at least 60%, more preferably at least 65% of the soluble solids protein is less than 550 g/mol.

The invention also relates to an aqueous fraction which can be obtained by the insect treatment process according to the invention.

In addition, the invention relates to an aqueous fraction containing at least 48 wt.% protein, at least 2 wt.% trehalose and having a lipid content of less than 7 wt.%, and weight percentages are based on the total dry weight of the aqueous fraction .

Preferably, the aqueous fraction contains at least 55 wt.%, more preferably at least 60 wt.%, even more preferably at least 65 wt.% protein, based on the total dry weight of the aqueous fraction.

Preferably, the aqueous fraction contains at least 2.5 wt.%, more preferably at least 3 wt.% trehalose based on the total dry weight of the aqueous fraction.

Preferably, the aqueous fraction has a lipid content of less than 6 wt.%, more preferably less than 4 wt.%, even more preferably less than 2 wt.%, based on the total dry weight of the aqueous fraction.

Preferably, the aqueous fraction contains 5 to 20 wt. % ash, preferably 7 to 15 wt. % ash, based on the total dry weight of the aqueous fraction.

In addition, the aqueous fraction contains less than 2 wt.% insoluble precipitates, preferably less than 1 wt.% insoluble precipitates, based on the total weight of the aqueous fraction.

The water fraction does not contain chitin.

Like the solid fraction, the aqueous fraction contains soluble protein, which is sufficiently reduced in size to facilitate digestion by the animals.

Preferably at least 90%, preferably at least 95%, more preferably at least 97% of the soluble protein in the aqueous fraction is less than or equal to 12400 g/mol.

More specifically, at least 45%, preferably at least 50%, more preferably at least 53% of the soluble protein in the aqueous fraction is less than 550 g/mol.

More specifically, the aqueous fraction has a solids content in the range of 5 to 15% by weight based on the total weight of the aqueous fraction.

When thickened, the concentrated aqueous fraction has a solids content of 55 to 75% by weight based on the total weight of the concentrated aqueous fraction.

The invention also relates to a concentrated aqueous fraction which can be obtained by the insect treatment process according to the invention, said treatment method then comprising an optional thickening step.

In addition, the invention relates to an oil fraction which can be obtained by the method of treating insects according to the invention.

The invention also relates to a powder which can be obtained by an insect treatment process comprising the following steps:

- separation of the cuticle from the soft part of insects,

- separation of the soft part of insects into an oil fraction, a solid fraction and an aqueous fraction,

- optionally, thickening of the water fraction,

- optionally, mixing the solid fraction with:

- all or part of the concentrated aqueous fraction, and/or

- all or part of the cuticle,

to get a mixture

- drying the solid fraction or mixture to obtain a dry solid fraction or dry mixture, respectively;

- grinding dry solid fraction or dry mixture.

In addition, the insect treatment method may have one or more of the features described above.

More specifically, the invention relates to a powder which can be obtained by the method for producing a powder, in particular to an insect powder according to the invention as described above.

As mentioned above, depending on whether the optional steps 5 and/or 6 of the method of treating insects according to the invention, namely the step of thickening the aqueous fraction and the step of mixing all or part of the cuticles and/or all or part of the concentrated aqueous fraction with solid fraction, and also in certain cases, depending on the conditions for their implementation, you can get different powders.

The invention also relates to a powder, in particular an insect powder, containing at least 71% by weight of protein and from 0.1 to 4% by weight of chitin, the weight percentages being based on the total dry weight of the powder.

Preferably, this powder has a protein content greater than or equal to 72 wt.%, more preferably greater than or equal to 74 wt.%, even more preferably greater than or equal to 75 wt.%, based on the total dry weight of the powder.

More specifically, this powder has a chitin content of 0.5 to 3% by weight, more preferably 0.8 to 2% by weight, even more preferably 0.8 to 1.7% by weight based on the total dry weight of the powder.

Preferably, said powder contains from 5 to 20 wt.%, preferably from 7 to 17 wt.% lipids, based on the total dry weight of the powder.

More specifically, said powder contains from 1 to 10 wt.%, preferably from 2 to 6 wt.% ash, based on the total dry weight of the powder.

In addition, said powder preferably contains from 3 to 20% by weight of carbohydrates based on the total dry weight of the powder.

More specifically, said powder preferably contains at least 0.1% by weight, more preferably at least 0.2% by weight of trehalose based on the total dry weight of the powder.

When the optional steps 5 and/or 6 are not carried out, a powder, in particular an insect powder, is obtained from the solid fraction only.

This powder contains at least 71% by weight of protein and 0.1 to 2% by weight of chitin, the weight percentages being based on the total dry weight of the powder.

Preferably, this powder has a protein content greater than or equal to 72 wt.%, more preferably greater than or equal to 74 wt.%, even more preferably greater than or equal to 75 wt.%, based on the total dry weight of the powder.

More specifically, this powder has a chitin content of 0.5 to 1.7% by weight based on the total dry weight of the powder.

Preferably, this powder contains from 5 to 17 wt.%, preferably from 10 to 15 wt.% lipids, based on the total dry weight of the powder.

More specifically, this powder contains from 1 to 10 wt.%, preferably from 2 to 6 wt.% ash, based on the total dry weight of the powder.

In addition, this powder preferably contains from 5 to 15 wt.%, more preferably from 7 to 13 wt.% carbohydrates based on the total dry weight of the powder.

More specifically, this powder preferably contains at least 0.2 wt.%, more preferably at least 0.3 wt.%, even more preferably at least 0.35 wt.% trehalose based on the total dry weight of the powder.

When steps 5 and 6 of the method according to the invention are carried out, it is also possible to obtain a powder from a mixture of the solid fraction, all or part of the cuticles and all or part of the concentrated aqueous fraction.

Thus, the invention also relates to a powder, in particular an insect powder, containing at least 65% by weight of protein, at least 10% by weight of carbohydrates and from 0.1 to 2% by weight of chitin, the weight percentages indicated on the basis of the total dry weight of the powder.

Preferably, said powder has a protein content greater than or equal to 70% by weight, more preferably greater than or equal to 74% by weight, based on the total dry weight of the powder.

More specifically, said powder has a chitin content of 0.2 to 1.5% by weight, more preferably 0.5 to 1.3% by weight, based on the total dry weight of the powder.

Preferably, said powder has a carbohydrate content greater than or equal to 12% by weight, more preferably greater than or equal to 14% by weight, based on the total dry weight of the powder.

More specifically, said powder preferably contains at least 0.7 wt.%, more preferably at least 0.9 wt.%, even more preferably at least 1 wt.% and even more preferably at least 1.2 wt. .% trehalose based on total dry weight of the powder.

Preferably, said powder contains 5 to 15% by weight, preferably 7 to 13% by weight lipids, based on the total dry weight of the powder.

More specifically, said powder contains from 3 to 10 wt.%, preferably from 4 to 8 wt.% ash, based on the total dry weight of the powder.

The residual moisture content of the powders according to the invention is 2% to 15%, preferably 5% to 10%, more preferably 4% to 8%. This moisture content can be determined, for example, by the method described in the CE regulation 152/2009 of 27-01-2009 (103°C/4h).

Preferably, the protein powders of the invention have a digestibility greater than or equal to 85% by weight of the total crude protein weight.

Digestibility is the digestibility of pepsin, measured by the method described in Directive 72/199/CE.

Preferably the digestibility is greater than or equal to 88%, more preferably greater than or equal to 92%.

The invention also relates to the use of the aqueous fraction according to the invention described above, the concentrated aqueous fraction according to the invention or the powder according to the invention containing at least 65% protein, at least 10 wt.% carbohydrates and from 0.1 to 2 wt.% chitin, as a flavoring agent, preferably in animal feed.

Finally, the invention relates to the use of the powder according to the invention in nutrition, preferably in animal feed.

Other characteristics and advantages of the invention will emerge from the following examples, given by way of illustration, in conjunction with Figure 1, which shows a diagram illustrating a detailed method for treating insects according to the invention.

Example 1 Method for treating insects according to the invention

Larvae of Tenebrio molitor have been used. After delivery, the larvae can be stored before slaughter at 4°C for 0-15 days in breeding tanks without significant degradation. The weight (age) of the larvae used varies and therefore their composition may also vary, as shown in Table 1 below.

Table 1 . Biochemical composition of Tenebrio molitor larvae depending on their weight

Biomass
(insects) mg 23 35 58 80 108 154 Dry matter %* 34 34 34.2 37.9 39.6 39.5 Ash %* 1.59 1.52 1.6 1.75 1.67 1.43 crude protein %* 22.6 22.2 22 23.2 23.1 23.2 Lipids %* 6.62 6.88 7.98 10.3 10.9 11.7

*% expressed in dry weight based on the wet weight of the larvae.

Stage 1: Killing insects

Live larvae (+4°C -+25°C) were transported in a 2 to 10 cm thick layer on a perforated conveyor belt (1 mm) to the blanching chamber. The insects were blanched with steam (nozzles or steam layer) at 98° C. with forced ventilation, or with water at 92-95° C. (spray nozzles), or in a mixed mode (water+steam). The residence time in the blanch chamber is between 5 seconds and 15 minutes, ideally 5 minutes.

The temperature of the larvae at the exit from the blanching ranges from 75°C to 98°C.

Stage 2: Separation of the soft part of the insects from the cuticle

After blanching, the larvae were transported to the feed funnel of the belt separator to separate the cuticles from the soft part of the larvae.

Preferably, separation is carried out immediately after killing, so that the larvae do not have time to cool to ambient temperature.

A belt separator 601 from Baader was used as a belt separator.

The diameter of the holes in the drum was 1.3 mm.

The soft part of the insects was collected in a container.

The cuticles were collected with a scraper.

Determination of the amount of trehalose in cuticles

The amount of trehalose in cuticles harvested in step 2 was measured as follows.

Trehalose was analyzed by GC-MS.

Temperature program: 150°C, then rise at 10°C/min to 260°C, after 5 minutes at this temperature rise at 25°C/min to 310°C and hold at this temperature for 2 minutes . Injector temperature: 280°C, interface: 250°C, split ratio: 10, injection volume: 1 µl. For example, a sH-RXI-5mS, 30 m x 0.25 mm x 0.25 µm column was used.

Sample preparation for analysis is carried out as follows: the exact amount of the sample (from 10 to 300 mg) is weighed into a Falcon tube, 9.75 ml of methanol is added to it, as well as 250 µl of an internal standard solution (myo-inositol, 25 µg/ml) in DMSO. The mixture is stirred at 80°C for 10 minutes, then 100 μl of BSTFA is added and the reaction mixture is stirred for another 30 minutes at ambient temperature, then 1 ml of acetonitrile is added and the resulting sample is injected into the GC-MS device.

The amount measured is 1.2 mg trehalose per g dry matter.

Stage 3: Maturation of the soft part of insects

The soft part of the insects is left in the recovery tank from stage 2 under stirring conditions for 1 hour at a temperature of about 90°C.

Stage 4: Separation of the soft part into a solid fraction, an aqueous fraction and an oil fraction

Then the soft part is separated into three fractions using a three-phase decanter. The decanter used was a Tricanter® Z23 decanter from Flottweg.

Separation conditions:

- consumption: up to 500 kg/h,

- rotation of the centrifuge drum: 4806 rpm (3000G);

- Y _min : 5% (1.4 rpm).

Three fractions are obtained from this separation step: an oil fraction, a solid fraction and an aqueous fraction.

These fractions have the characteristics shown in the following table 2.

table 2 . Characteristics of oil fraction, solid fraction and water fraction

Dry Matter (%) Protein (%)* Oil
(%)* Ash
(%)* Carbohydrates
(%)* solid fraction 56 74.1 12.9 4 10 Water fraction 10 57 4 9 23 Oil fraction >99.5 <0.5 >99.5 <0.25 <0.25

* Average results calculated on several samples of each fraction, expressed in % solids

Determination of the size of the soluble protein in the solid fraction and the aqueous fraction

Solid sample preparation (solid fraction): Dissolve 30 mg of sample in 1 L of mobile phase and filter using a Chromafil xtra PES-45/25 filter.

Liquid sample preparation (aqueous fraction): 400 µl is dissolved in 1600 µl of mobile phase and filtered using a Chromafil xtra PES-45/25 filter just before injection. 1.5 ml of the sample thus prepared is centrifuged for 15 minutes at 12000 rpm (10625 g).

Chromatography conditions (Nexera XR HPLC from Shimadzu) are as follows: Superdex Peptide GL 10/300 column (GE Healthcare) was used, detection was performed with a DAD detector at 215 nm, the mobile phase velocity consisting of ACN (acetonitrile)/H ₂ O/TFA ( trifluoroacetic acid) (30/70/0.1) was 0.3 ml/min, the analysis was carried out at 25°C.

The soluble protein size distribution of the solid fraction is shown in Table 3 below.

Table 3. Size distribution of soluble protein in the solid fraction

Molecular weight (kDa) % > 12.4 13.8 12.4-6.5 14 6.5-1.4 3.8 1.4-0.55 2.1 <0.55 67.3

The size distribution of soluble protein in the aqueous fraction is shown in Table 4 below.

Table 4 . Size distribution of soluble protein in the aqueous fraction

Molecular weight (kDa) % >12.4 2.7 12.4-6.5 13.4 6.5-1.4 19 1.4-0.55 11.5 <0.55 53.4

Determination of the amount of trehalose in the solid fraction and aqueous fraction

The amount of trehalose in these fractions was measured as follows.

Trehalose was analyzed by GC-MS.

Temperature program: 150°C, then rise at 10°C/min to 260°C, after 5 minutes at this temperature rise at 25°C/min to 310°C and hold at this temperature for 2 minutes. Injector temperature: 280°C, interface: 250°C, split ratio: 10, injection volume: 1 µl.

Sample preparation for analysis is carried out as follows: the exact amount of the sample (from 10 to 300 mg) is weighed into a Falcon tube, 9.75 ml of methanol is added to it, as well as 250 µl of an internal standard solution (myo-inositol, 25 µg/ml) in DMSO. The mixture is stirred at 80°C for 10 minutes, then 100 μl of BSTFA is added and the reaction mixture is stirred for another 30 minutes at ambient temperature, then 1 ml of acetonitrile is added and the resulting sample is injected into the GC-MS device.

The amount measured in the solid fraction is 3.82 mg of trehalose per g of solids.

The amount measured in the water fraction is 33.2 mg of trehalose per g of solids.

In addition, the aqueous fraction contains less than 1 wt.% insoluble precipitates based on the total weight of the aqueous fraction.

Stage 5: Thickening of the water fraction

Then, the aqueous fraction obtained in step 4 is thickened by evaporation using a falling film evaporator.

The resulting concentrated aqueous fraction has a solids concentration of approximately 65%.

Step 6 (Optional): Mixing the concentrated aqueous fraction and/or cuticles with the solid fraction

Step 6 was not performed in this example.

Stage 7: Drying of the solids

The solids obtained in step 4 are dried using a disk dryer from Haarslev for 5 hours to obtain a dry solids or dry mixture.

From a microbiological point of view, the solid fraction contains less than 10 cfu/g of enterobacteria.

Stage 8: Grinding

Finally, the dry solids were milled with a continuous hammer mill (6 reversible sliders, 8 mm thick). The crusher is fed through a funnel with an adjustable flow rate hatch (180 kg/h). The perforated grating used to control the output particle size distribution has a mesh size of 0.8 mm. The motor speed is 3000 rpm (electric motor, power input 4 kW (5.5 hp)).

The characteristics of the resulting insect powder are shown in Table 5 below.

Table 5. Characteristics of the insect powder obtained in example 1

Protein Chitin Ash Lipids Carbohydrates Trehalose 75.1% 1.3% 4% 12.5% 10% 0.38%

*Percentages shown are weight percent based on the total dry weight of the insect powder.

Example 2 Method for treating insects according to the invention

Steps 1-5 were performed as described in Example 1.

Step 6 (Optional): Mixing the concentrated aqueous fraction and cuticles with the solid fraction

All (100%) of the concentrated aqueous fraction obtained in step 5, as well as 0.05 wt.% of the cuticles collected in step 2, were mixed with the entire solid fraction obtained in step 4 to obtain a mixture.

A Vrieco-Nauta® conical screw mixer was used.

Stage 7: Drying the mixture

The solid fraction obtained in step 4 was dried using a disk dryer from Haarslev for 5 hours to obtain a dry mixture.

From a microbiological point of view, the dry mix contains less than 10 cfu/g of enterobacteria.

Stage 8: Grinding

Finally, the dry mixture was crushed using a continuous hammer mill (6 reversible moving parts, 8 mm thick). The feed to the crusher was carried out through a funnel with a hatch with adjustable flow rate (180 kg/h). The perforated grid used to control the outlet particle size distribution has a mesh size of 0.8 mm. The motor speed is 3000 rpm (electric motor, power input 4 kW (5.5 hp)).

The characteristics of the resulting insect powder are shown in Table 6 below.

Table 6. Characteristics of the insect powder obtained in example 2.

Protein Chitin Ash Lipids Carbohydrates Trehalose 66% 1% 6% eleven% 13% 1.1%

*Percentages shown are weight percent based on the total dry weight of the insect powder.

Claims (17)

1. A method for processing insects for feed to obtain a solid fraction or an aqueous fraction, comprising the following steps: - killing insects by scalding with hot water at a temperature of 87-100°C or blanching at a temperature of 80-105°C; - separation of the cuticle from the soft part of insects, using a belt filter press or a belt separator, where the soft parts are muscles, internal organs, body fluids, water and hemolymph, and then - separation of the soft part of the insects into an oil fraction, a solid fraction and an aqueous fraction, where the separation is carried out in two stages: when using a two-phase decanter at the first stage to obtain a solid and liquid fraction, at the second stage of a centrifuge to separate the liquid fraction into oil and water fractions, or separation is carried out using a three-phase decanter directly into an aqueous fraction, a solid fraction and an oil fraction. 2. The method according to claim 1, comprising the step of maturing the soft part of the insects to the step of separating the soft part of the insects into an oil fraction, a solid fraction and an aqueous fraction, while the soft part of the insects is subjected to mixing. 3. The method according to claim 1 or 2, wherein the separation of the cuticles from the soft part of the insects is carried out using a filter press. 4. The method according to claim 1 or 2, in which the separation of the cuticles from the soft part of the insects is carried out using a belt separator. 5. The method according to any one of paragraphs. 1-4, including the step of concentrating the aqueous fraction. 6. The method according to any one of paragraphs. 1-5, further comprising the step of mixing the solid fraction with: - all or part of the concentrated aqueous fraction, and/or - all or part of the cuticle to get a mixture. 7. The method according to any one of paragraphs. 1-6, which includes the step of drying the solid fraction or mixture to obtain a dry solid fraction or dry mixture, respectively. 8. The method of claim 7, further comprising the step of grinding the dry solids or dry mixture. 9. Solid fraction for feed, obtained from insects by the method of claim 1, containing at least 71 wt.% protein and from 0.1 to 2 wt.% chitin, and weight percentages are indicated in relation to the total dry weight of the solid fraction, while at least 60% of soluble proteins have a size of less than 550 g/mol. 10. Aqueous feed fraction obtained from insects by the method of claim 1, containing at least 48 wt.% protein, at least 2 wt.% trehalose and having a lipid content of less than 7 wt.%, and weight percentages are indicated in the calculation in relation to the total dry weight of the aqueous fraction. 11. The use of an aqueous fraction for feed according to claim 10 as a flavoring agent. 12. Use according to claim 11 in animal feed.

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