METHOD FOR TREATING INSECTS, IN WHICH THE CUTICLES ARE SEPARATED FROM THE SOFT PART OF THE INSECTS, AND THE SOFT PART IS THEN SEPARATED INTO THREE FRACTIONS

Abstract

The invention relates to a method for treating insects, comprising the separation of the cuticles from the soft part of the insects, followed by the separation of the soft part of the insects into an oil fraction, a solid fraction and an aqueous fraction. The invention further relates to powders, in particular a powder obtainable by the method of treating insects according to the invention, and to the use of these powders in food.

Claims

1. Process for treating insects comprising the following steps: separating the cuticles from the soft part of the insects, then separating the soft part of the insects into a fat fraction, a solid fraction and an aqueous fraction.

2. Process according to claim 1, comprising a step of maturation of the soft part of the insects, prior to the step of separating the soft part of the insects into a fat fraction, a solid fraction and an aqueous fraction.

3. Process according to claim 1, in which separating the cuticles from the soft part of the insects is carried out using a filter press.

4. Process according to claim 1, in which separating the cuticles from the soft part of the insects is carried out using a belt separator.

5. Solid fraction obtainable by the process according to claim 1.

6. (canceled)

7. Process according to claim 1, comprising a step of concentrating the aqueous fraction.

8. Aqueous fraction obtainable by the process according to claim 1.

9. Aqueous fraction comprising at least 48% by weight proteins, at least 2% by weight trehalose and having a lipid content less than 7% by weight, the percentages by weight being indicated with respect to the total dry weight of the aqueous fraction.

10. Process according to claim 1, also comprising a step of mixing the solid fraction with: all or part of the concentrated aqueous fraction; and/or all or part of the cuticles, in order to obtain a mixture.

11. Process according to claim 1, comprising a step of drying the solid fraction or the mixture in order to obtain a dry solid fraction or a dry mixture, respectively.

12. Process according to claim 11, also comprising a step of grinding the dry solid fraction or the dry mixture.

13. Powder obtainable by the process according to claim 12.

14. (canceled)

15. Powder comprising at least 65% by weight proteins, at least 10% by weight carbohydrates and comprising between 0.1 and 2% by weight chitin, the percentages by weight being indicated with respect to the total dry weight of powder.

16. Use as flavouring of an aqueous fraction according claim 8.

17. Use of a powder according to claim 13, in nutrition.

18. Use according to claim 16, in animal nutrition.

19. Use as flavouring of the powder according to claim 15.

20. Use according to claim 17, in animal nutrition.

Description

[0220] Other characteristics and advantages of the invention will become apparent from the following examples, given by way of illustration, with reference to:

[0221] FIG. 1, which is a diagram illustrating the detailed process for treating insects according to the invention.

EXAMPLE 1: Process for Treating Insects According to the Invention

[0222] The larvae of Tenebrio molitor were used. Upon receipt of the larvae, they can be stored at 4 C. for 0 to 15 days in their rearing tanks without major degradation before being killed. The weight of the larvae (age) used is variable and as a result their composition can vary, as illustrated in Table 1 below:

TABLE-US-00001 TABLE 1 Biochemical composition of the larvae of Tenebrio molitor according to the weight thereof. 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 proteins %* 22.6 22.2 22 23.2 23.1 23.2 Lipids %* 6.62 6.88 7.98 10.3 10.9 11.7 *The % s are expressed in dry weight with respect to the wet weight of larvae.

Step 1: Killing the Insects

[0223] Living larvae (+4 C. to +25 C.) are conveyed in layers with a thickness comprised between 2 and 10 cm, on a perforated conveyor belt (1 mm) to a blanching chamber. The insects are thus blanched with steam (steam nozzles or bed) at 98 C. under forced ventilation or with water at 92-95 C. (spray nozzles) or in mixed mode (water+steam). The residence time in the blanching chamber is comprised between 5 seconds and 15 minutes, ideally 5 min.

[0224] The temperature of the larvae after blanching is comprised between 75 C. and 98 C.

Step 2: Separating the Soft Part from the Cuticles of the Insects

[0225] The larvae, once blanched, are conveyed to the feed hopper of a belt separator, in order to separate the cuticles from the soft part of the larvae.

[0226] Advantageously, the separation is performed immediately after killing so that the larvae do not have time to cool to ambient temperature.

[0227] The belt separator used is a belt separator 601 from Baader.

[0228] The diameter of the perforations of the drum is 1.3 mm.

[0229] The soft part of the insects is recovered in a tank.

[0230] The cuticles are recovered using a scraper blade.

Determining the Quantity of Trehalose of the Cuticles

[0231] The quantity of trehalose in the cuticles recovered in step 2 was measured in the following manner:

[0232] The trehalose is analyzed by GC-MS.

[0233] Temperature programme: 150 C., followed by an increase of 10 C./min up to 260 C., after 5 minutes at this temperature, an increase of 25 C./min up to 310 C. and maintaining this temperature for 2 minutes. Temperature of the injector: 280 C., of the interface: 250 C., the split ratio is 10, the injection volume is 1 L. For example, an sH-RXI-5m5 column, 30 m0.25 mm0.25 m is used.

[0234] Preparation of the sample for analysis is carried out in the following manner: a precise quantity of the sample (between 10 and 300 mg) is weighed in a Falcon tube, 9.75 mL of methanol is added thereto as well as 250 L of an internal standard solution (myo-inositol, 25 g/mL) in DMSO. The mixture is stirred at 80 C. for 10 minutes, 100 L of BSTFA is then added and the reaction mixture is stirred for 30 additional minutes at ambient temperature, 1 mL of acetonitrile is then added and the sample thus prepared is injected on a GC-MS device.

[0235] The quantity measured is 1.2 mg of trehalose per g of dry matter.

Step 3: Maturation of the Soft Part of the Insects

[0236] The soft part of the insects is left to rest in the collecting tank of step 2, under stirring for 1 h and at a temperature of approximately 90 C.

Step 4: Separating the Soft Part into a Solid Fraction, an Aqueous Fraction and a Fat Fraction

[0237] The soft part is then separated into three fractions using a three-phase decanter. The decanter used is the Tricanter Z23 from Flottweg.

[0238] Separation conditions: [0239] Flow rate: up to 500 Kg/h; [0240] Bowl speed: 4806 rpm (3000 G); [0241] Minimum Y: 5% (1.4 rpm).

[0242] Three fractions are obtained at the end of this separation phase: a fat fraction, a solid fraction and an aqueous fraction.

[0243] These fractions have the characteristics indicated in Table 2 below:

TABLE-US-00002 TABLE 2 Characteristics of the fat fraction, the solid fraction and the aqueous fraction. Dry Matter Proteins Oil Ash Carbohydrates (%) (%)* (%)* (%)* (%)* Solid 56 74.1 12.9 4 10 fraction Aqueous 10 57 4 9 23 Fraction Fat >99.5 <0.5 >99.5 <0.25 <0.25 fraction *Average results calculated over several samples of each of the fractions, expressed with respect to the % of dry matter

Determining the Size of the Soluble Proteins of the Solid Fraction and of the Aqueous Fraction

[0244] Preparation of the solid sample (solid fraction): 30 mg of the sample is solubilized in 1 L of mobile phase and filtered using the Chromafil Xtra PES-45/25 filter.

[0245] Preparation of the liquid sample (aqueous fraction): 400 L is solubilized in 1600 L of the mobile phase and filtered using the Chromafil Xtra PES-45/25 filter, just before injection. 1.5 mL of the sample thus prepared is centrifuged for 15 min at 12000 rpm (10625 g).

[0246] The conditions for implementing the chromatography (HPLC Nexera XR from Shimadzu) are as follows: the column used is a Superdex Peptide GL 10/300 (GE Healthcare), detection is carried out by a DAD detector at 215 nm, the speed of the mobile phase is 0.3 mL/min and it is composed of ACN (acetonitrile)/H.sub.2O/TFA (trifluoroacetic acid) (30/70/0.1), analysis is carried out at 25 C.

[0247] The size distribution of the soluble proteins of the solid fraction is shown in

[0248] Table 3 below:

TABLE-US-00003 TABLE 3 The size distribution of the soluble proteins 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

[0249] The size distribution of the soluble proteins of the aqueous fraction is shown in Table 4 below.

TABLE-US-00004 TABLE 4 The size distribution of the soluble proteins in the aqueous fraction Determining the quantity of trehalose in the solid fraction and 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

[0250] The quantity of trehalose in these fractions was measured in the following manner:

[0251] The trehalose is analyzed by GC-MS.

[0252] Temperature programme: 150 C., followed by an increase of 10 C./min up to 260 C., after 5 minutes at this temperature, an increase of 25 C./min up to 310 C. and maintaining this temperature for 2 minutes. Temperature of the injector: 280 C., of the interface: 250 C., the split ratio is 10, the injection volume is 1 L.

[0253] Preparation of the sample for analysis is carried out in the following manner: a precise quantity of the sample (between 10 and 300 mg) is weighed in a Falcon tube, 9.75 mL of methanol is added thereto as well as 250 L of an internal standard solution (myo-inositol, 25 g/mL) in DMSO. The mixture is stirred at 80 C. for 10 minutes, 100 L of BSTFA is then added and the reaction mixture is stirred for 30 additional minutes at ambient temperature, 1 mL of acetonitrile is then added and the sample thus prepared is injected on a GC-MS device.

[0254] The quantity measured in the solid fraction is 3.82 mg of trehalose per g of dry matter.

[0255] The quantity measured in the aqueous fraction is 33.2 mg of trehalose per g of dry matter.

[0256] In addition, the aqueous fraction comprises less than 1% by weight insoluble sediments with respect to the total weight of the aqueous fraction.

Step 5: Concentrating the Aqueous Fraction

[0257] The aqueous fraction obtained in step 4 is then concentrated by evaporation, using a falling film evaporator.

[0258] The concentrated aqueous fraction obtained has a concentration of dry matter of approximately 65%.

Step 6 (Optional): Mixing the Concentrated Aqueous Fraction and/or the Cuticles with the Solid Fraction

[0259] Step 6 was not implemented in this example.

Step 7: Drying the Solid Fraction

[0260] The solid fraction obtained in step 4 is dried using a disc dryer from Haarslev for 5 h in order to obtain a dry solid fraction or a dry mixture.

[0261] From a microbiological perspective, the solid fraction comprises less than 10 UFC/g of enterobacteria.

Step 8: Grinding

[0262] The dry solid fraction is finally ground using a continuous hammer mill (6 reversible moving partsthickness 8 mm). The grinder is fed by a hopper with a flow rate control flap (180 kg/h). The perforated grill used to control the output granulometry is 0.8 mm. The speed of rotation of the motor is 3000 rpm (electric motorization, absorbed power 4 kW (5.5 HP)).

[0263] The characteristics of an insect powder obtained are given in Table 5 below.

TABLE-US-00005 TABLE 5 Characteristics of an insect powder obtained in Example 1. Proteins Chitin Ash Lipids Carbohydrates Trehalose 75.1% 1.3% 4% 12.5% 10% 0.38% * The percentages indicated are percentages by weight with respect to the total dry weight of the insect powder.

EXAMPLE 2: Process for Treating Insects According to the Invention

[0264] Steps 1 to 5 were implemented as described in Example 1.

Step 6 (Optional): Mixing the Concentrated Aqueous Fraction and the Cuticles with the Solid Fraction

[0265] All (100%) of the concentrated aqueous fraction obtained in step 5 as well as 0.05% by weight cuticles recovered in step 2 were mixed with all of the solid fraction obtained in step 4 in order to obtain a mixture.

[0266] A conical screw mixer from Vrieco-Nauta was used.

Step 7: Drying the Mixture

[0267] The mixture obtained in step 6 is dried using a disc dryer from Haarslev for 5 h in order to obtain a dry mixture.

[0268] From a microbiological perspective, the dry mixture comprises less than 10 UFC/g of enterobacteria.

Step 8: Grinding

[0269] The dry mixture is finally ground using a continuous hammer mill (6 reversible moving partsthickness 8 mm). The grinder is fed by a hopper with a flow rate control flap (180 kg/h). The perforated grill used to control the output granulometry is 0.8 mm. The speed of rotation of the motor is 3000 rpm (electric motorization, absorbed power 4 kW (5.5 HP)).

[0270] The characteristics of an insect powder obtained are given in Table 6 below.

TABLE-US-00006 TABLE 6 Characteristics of the insect powder obtained in Example 2. Proteins Chitin Ash Lipids Carbohydrates Trehalose 66% 1% 6% 11% 13% 1.1% * The percentages indicated are percentages by weight with respect to the total dry weight of the insect powder.