METHOD FOR PRODUCING NUTRIENTS FROM INSECTS

Abstract

The invention relates to 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.

Claims

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

2. The preparation method according to claim 1, wherein the insects are at least one of 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 Sarnia ricini.

3. The preparation method according to claim 1, comprising a step prior to the grinding, comprising blanching the insects.

4. The preparation method according to claim 1, wherein the grinding results in the ground material having a particle size of less than 2.0 mm.

5. The preparation method according to claim 1, wherein the enzymatic hydrolysis of is performed with one or more proteases.

6. The preparation method according to claim 1, wherein the pressing is performed with a screw press.

7. The preparation method according to claim 1, wherein the subjecting is performed with a plate separator.

8. The preparation method according to claim 1, wherein the subjecting is performed with a plate separator at a temperature ranging from 50 to 80° C.

9. The preparation method according to claim 1, further comprising drying the aqueous protein fraction to obtain a protein powder.

10. The preparation method according to claim 1, further comprising filtering and/or clarifying the oil fraction.

11. An aqueous protein fraction obtained by, grinding insects to obtain a ground material, subjecting the ground material to enzymatic hydrolysis to obtain a hydrolyzed ground material, pressing the hydrolyzed ground material to obtain a chitin-enriched solid fraction and a liquid fraction, and subjecting the liquid fraction to a physical separation to obtain the aqueous protein fraction and an oil fraction, wherein at least 20% by mass of the proteins and protein fragments contained in said aqueous protein fraction have a molecular weight of between 1300 Da and 5700 Da.

12. The aqueous protein fraction according to claim 11, wherein a protein content comprises proteins, protein fragments and free amino acids and is at least equal to 60% by mass of the dry mass of said aqueous protein fraction.

13. The aqueous protein fraction according to claim 11, having a lipid content less than 20% by mass of the dry mass of said aqueous protein fraction.

14. An oil fraction obtained by performing the method of claim 1.

15. A chitin-enriched solid fraction obtained by, grinding insects to obtain a ground material, subjecting the ground material to enzymatic hydrolysis to obtain a hydrolyzed ground material, pressing the hydrolyzed ground material to obtain a chitin-enriched solid fraction and a liquid fraction, and subjecting the liquid fraction to a physical separation to obtain an aqueous protein fraction and an oil fraction, wherein a chitin content of the chitin-enriched solid fraction is at least equal to 15% by mass of the dry mass of said chitin-enriched solid fraction.

16. The preparation method according to claim 10, further comprising filtering and/or clarifying the oil fraction by polishing or by decantation.

17. The preparation method according to claim 8, wherein the subjecting is performed at a temperature ranging from 65 to 75° C.

18. The preparation method according to claim 2, wherein the insects are Hermetia illucens.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0090] FIG. 1 is a flow chart of the steps of a method according to the invention. The method notably comprises steps of boiling the larvae, grinding, enzymatic hydrolysis, pressing, separating with a plate separator and then drying of the aqueous protein fraction, known as the “oil-freed hydrolyzate” or the “insect protein hydrolyzate”. This flow chart corresponds to Protocol 1.

[0091] FIG. 2 is a flow chart of the steps of a method which is not according to the invention. The method notably comprises steps of boiling the larvae, grinding, enzymatic hydrolysis and separating in a centrifuge to obtain an aqueous protein fraction. The method does not comprise a pressing step. This flow chart corresponds to Protocol 2.

EXAMPLE

[0092] Materials and Methods

[0093] Each content was measured on samples of each of the fractions according to the following methods:

[0094] Method for measuring the protein content (proteins, protein fragments and free amino acids): the protein content was measured by nitrogen assay on the raw material (Kjeldahl method) followed by multiplication of the nitrogen content by a coefficient of 6.38 so as to obtain the protein content of the raw material. The protein content of the raw material was multiplied by the percentage of dry mass so as to obtain the protein content by mass of the dry mass.

[0095] Method for measuring the molecular weights of the proteins and protein fragments: the aqueous protein fraction samples were passed through a gel filtration column in which the rate of migration of the molecules depends on their molecular weight: the large molecules migrate the fastest whereas the smallest emerge at the end of the analysis. The UV detector detected at 214 nm the exiting proteins. The peak size is proportional to the amount of exiting proteins. The various hydrolyzates were able to be compared by comparing the area of the peaks between given fixed times. By means of standards (reference proteins of known molecular weight: ovalbumin, lysozyme, protinin, alpha-chain insulin, human angiotensin II, L-tryptophan), a retention time equivalence as a function of the molecular weight was determined.

[0096] Method for measuring the lipid content: the lipid content was measured by MGRA-H assay by an accredited laboratory, COFRAC.

[0097] Method for measuring the chitin content: the chitin content was measured by glucosamine assay with the aid of ion chromatography. The glucosamine content is then divided by a factor of 1.062 so as to obtain the chitin content.

[0098] Method for measuring the mineral content: the mineral content was determined by measuring the total mass of the raw ash. A sample, placed in a crucible, is incinerated at 550° C. in an electric muffle furnace with a thermostat. The residue is weighed.

[0099] Protocol 1: Preparation of Nutrients from Insects—According to the Invention

[0100] 165 kg of live black soldier fly (Hermetia illucens) larvae were used in this protocol. The dry mass content and the composition of the dry mass of a larval ground material are presented in Table 1.

[0101] The larvae were placed on a gauze and then immersed in water at a temperature of 90° C. for 5 minutes. The mass of the larvae after the blanching step was about 196 kg, which corresponds to a water uptake of 31 kg.

[0102] Step a)

[0103] The blanched larvae were introduced into an Urschel Comitrol 1700 brand grinding mill and ground so as to obtain a ground material with a mean particle size of 0.5 mm. The temperature of the ground material at the outlet of the grinding mill was about 40-45° C.

[0104] Step b)

[0105] The ground material was subsequently introduced into a tank with stirring with 0.4 kg of protease. The temperature was raised to 60° C. The pH was 8. In order to facilitate the stirring, water was added to the mixture during the hydrolysis.

[0106] A centrifugal pump was also installed on the reactor to improve the stirring of the mixture.

[0107] After 3 hours of stirring, the temperature of the mixture was raised to 80° C. to stop the enzymatic reaction.

[0108] Step c)

[0109] The hydrolyzed ground material was subsequently pressed with an Olexa brand screw press of MBU 75 wet-route press type equipped with a screen with a pore size of 2 mm. The temperature during the pressing was 85° C. The press shutter was adjusted so as to be three-quarters closed.

[0110] A press cake corresponding to the chitin-enriched solid fraction (mass: 18 kg) and a press juice corresponding to the liquid fraction (mass: 223 kg) were thus obtained.

[0111] The analyses of the press cake and of the press juice are presented in Table 2. The yields for this step are presented in Table 4.

[0112] Step d)

[0113] The liquid fraction heated to about 75° C. was subsequently placed in a GEA Westfalia plate separator of SAOH type, so as to obtain three fractions: [0114] an oil fraction, with a density of about 0.9; [0115] an aqueous protein fraction, with a density of about 1.0; and [0116] a solid residue fraction with a density of 1.1.

[0117] The aqueous protein fraction did not have a ring of fat after centrifugation of a sample, which proves that the separation step was successfully performed. Moreover, it should be noted that no emulsion was observed with Protocol 1.

[0118] The analyses of the three fractions are presented in Table 3. The yields for this step are presented in Table 4.

[0119] Other Steps

[0120] The protein-enriched aqueous protein fraction was subsequently dried by means of a horizontal spray atomizer. The aqueous protein fraction was sprayed in the form of microspheres via nozzles in a turbine which makes it possible to generate a convergent conical hot air stream of very high density and small dimensions. The temperature of the hot air was 200-210° C. at the inlet and 90-96° C. at the outlet.

[0121] A protein powder was thus obtained from the aqueous protein fraction. The powder contained 76.8% by mass of protein.

[0122] Protocol 2: Preparation of Nutrients from Insects—Outside the Invention

[0123] 0.507 kg of live black soldier fly (Hermetia illucens) larvae were used in this protocol.

[0124] The dry mass content and the composition of the dry mass of a larval ground material are presented in Table 1.

[0125] The larvae were boiled by immersion in boiling water in a laboratory reactor for 5 minutes with very gentle stirring and then placed on a screen for draining. The mass of the larvae after the blanching step was about 0.566 kg, which corresponds to a water uptake of 59 g.

[0126] Step a)

[0127] 194 g of water were added to the blanched larvae, which were subsequently ground in a laboratory grinding mill equipped with a knife, for 1 minute.

[0128] Step b)

[0129] 1.52 g of the same protease as used in protocol 1 were added to the ground material. The temperature was raised to 55° C. The pH was 7.2. After 4 hours of stirring, the temperature of the mixture was raised to 90° C. for 5 minutes to stop the enzymatic reaction.

[0130] The hydrolyzed ground material heated to 90° C. was subsequently placed in a bottle and centrifuged for 8 minutes at 3000×G so as to obtain four fractions: [0131] an oil fraction, with a density of about 0.9 (45 g); [0132] an emulsion, with a density of about 0.95 (58 g); [0133] an aqueous protein fraction, with a density of about 1.0 (425 g); and [0134] a solid residue fraction (223 g).

[0135] It should be noted that an emulsion was observed with Protocol 2. This emulsion was separated from the oil fraction and from the aqueous protein fraction for the analyses. The analyses of the three fractions (oil, aqueous protein and solid residues) are presented in Table 3. The yields for this step are presented in Table 5.

[0136] The aqueous protein fraction comprised 62.3% by mass of protein.

[0137] Analysis of the Fractions Obtained by Performing Protocols 1 and 2

[0138] 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-US-00001 TABLE 1 Percentage of dry Chitin Protein Lipids Others mass Minerals (1) (2) (3) (4) Protocol 1 33.7% 6.1% 8.5% 35.1% 48.3% 2% Protocol 2 36.0% 5.3% — 45.9% 48.8% —

[0139] (1) The chitin content was not measured in protocol 2.

[0140] (2) The protein content of the larvae of protocol 1 is evaluated by means of the total nitrogen content on the solids (6.1%) from which is subtracted the nitrogen contained in the chitin (0.6% since chitin contains 6.89% of nitrogen), i.e. 5.5% of protein nitrogen (multiplied by 6.38), i.e. 35.1% of protein in dry matter. Given that the chitin content was not measured in protocol 2, the protein content was not corrected. It is thus overestimated by about 10%.

[0141] (3) The lipid content was measured directly in protocol 1. In protocol 2, the lipid content was calculated by determining the difference with the mineral content and the protein content (100%−(% minerals+% protein)). The lipid content is probably slightly overestimated in protocol 2 (chitin not assayed).

[0142] (4) The “others” column corresponds to the difference between the dry matter and the sum of the minerals, chitin, protein and fat in protocol 1.

[0143] Table 2 below corresponds to the analysis of the liquid fraction and chitin-enriched solid fraction after pressing: percentage of dry mass and content of certain constituents by mass of the dry mass.

TABLE-US-00002 TABLE 2 Percentage Others of dry (by matter Minerals Chitin Protein Lipids difference) Liquid 22.6% 4.3% Not 35.3% 57.6%  2.8% fraction measured Chitin- 46.3% 7.8% 27.5% 38.3% 14.9% 11.5% enriched solid fraction

[0144] Table 3 corresponds to the analysis of the aqueous protein, oil and solid residue fractions: percentage of dry mass and content of certain constituents by mass of the dry mass.

TABLE-US-00003 TABLE 3 Dry Protein Lipids Others (by mass Minerals Chitin (1) (2) (3) difference) Fractions Aqueous 10.5% 8.3% 0.4% 76.8% <4.8% 9.7-14.5% obtained protein according fraction to Protocol Oil fraction 64.7% 0.5% Not  1.1% 77.3% 21.0% 1 measured Solid 22.9% 4.3% 0.3% 29.3% 60.7%  6.6% residue fraction Fractions Aqueous 10.5% 7.4% Not 62.3% 30.4% — obtained protein measured according fraction to Protocol Oil fraction 98.0% 1.7% Not  0.7% 97.6% — 2 measured Solid 27.9% 4.7% Not 47.0% 49.0% — residue measured fraction

[0145] (1) The chitin content was not measured in protocol 2.

[0146] (2) The protein contents in protocol 2 are overestimated since the chitin nitrogen was not subtracted.

[0147] (3) For protocol 2, the lipid contents are calculated by determining the difference with the mineral content and the protein content (100%−(% minerals+% protein)).

[0148] Conclusion:

[0149] The aqueous protein fraction obtained with Protocol 1 has a higher protein content than that obtained with Protocol 2 (76.8% versus 62.3%). Furthermore, the aqueous protein fraction obtained with Protocol 1 has a lipid content which is very much lower than that obtained with Protocol 2 (4.8% versus 30.4%). These results show that the pressing step made it possible to significantly increase the purity of the aqueous protein fraction and to avoid an emulsion during the physical separation.

[0150] Yields for Protocols 1 and 2

[0151] The yield for protocol 1 corresponds to Table 4.

TABLE-US-00004 TABLE 4 Dry Mass mass Protein Lipids Minerals Chitin Others (kg) (kg) (kg) (kg) (kg) (kg) (kg) Raw 165 55.6 19.5 26.9 3.4 4.7 1.1 material (larvae) Press 18 8.4 3.2 1.2 0.7 2.3 1.0 cake (chitin- enriched solid fraction) Press 223 50.3 17.8 29.0 2.2 Not 1.4 juice measured (liquid fraction) Total 241.0 58.7 21.0 30.2 2.8 2.3 2.4 Aqueous 143 15.0 11.5 <0.7 1.2 Not 1.5 protein measured fraction Oil 14.0 9.1 0.4 7.0 0.0 Not 1.9 fraction measured Solid 64.5 14.8 4.3 9.0 0.6 Not 0.8 residue measured fraction Total 221.5 38.8 16.3 16.7 1.9 Not 4.2 measured

[0152] The yield for protocol 2 corresponds to Table 5.

TABLE-US-00005 TABLE 5 Mass Dry mass Protein Minerals (g) (g) (kg) Lipids (g) (g) Chitin (g) Raw material (larvae) 507 182.7 83.8 90.7 9.8 Not measured Solid residue fraction 223 62.3 29.2 30.5 2.9 Not measured obtained after centrifugation Aqueous protein 425 44.8 31.3 13.6 4.9 Not measured fraction obtained after centrifugation Oil fraction 45 44.1 0.3 43.1 0.8 Not measured obtained after centrifugation Emulsion 58 Not Not Not Not Not measured obtained after measured measured measured measured centrifugation Total 751 151.2 60.8 87.2 8.6 Not measured

[0153] The yield for protocol 2 corresponds to Table 5.

[0154] Analysis of the Molecular Weight (Da) of the Proteins and Protein Fragments of the Aqueous Protein Fraction Obtained According to Protocol 1

[0155] Table 6 below corresponds to the analysis of the molecular weights of the proteins and protein fragments of the aqueous protein fraction obtained according to Protocol 1.

TABLE-US-00006 TABLE 6 Molecular weights (MW) in Da Percentage (%) MW > 14 000 10.97%  14 000 < MW > 10 000 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%

[0156] Conclusion:

[0157] the aqueous protein fraction obtained according to Protocol 1 contains 29.54% of proteins and protein fragments with a molecular weight of less than 1300 Da relative to the total amount of proteins and protein fragments of the aqueous protein fraction. It also contains about 50% of proteins and protein fragments with a molecular weight of between 1300 Da and 5700 Da, which is particularly advantageous from a nutritional viewpoint.