Patent ID: 12201124

DETAILED DESCRIPTION

Insects, and particularly preferably insect larvae, are used as starting material for protein recovery. Insect larvae of Hermetia illucens (black soldier fly),Ceratitis capitata(Mediterranean fruit fly), and/orTenebrio molitor(flour beetle) are particularly preferred. However, other insects and preferably their insects in the larval stage may also be considered.

In a first process step 1, the insect larvae are killed. The killing can be done by treatment in a hot water bath.

In a second process step 2, the insect larvae can optionally be cleaned. This can be done by sieving.

In a third process step 3, the insect larvae are comminuted to an insect pulp.

Here, the larvae are crushed (e.g., ground) to facilitate digestion by subsequent pH reduction. This can be done by means of a mill or press. The comminution can advantageously be performed to a mean particle size <2 mm, in particular to a mean particle size or grain size between 1 to 2 mm. A meat grinder can be used for this purpose, for example. Smaller particle sizes may allow better disintegration, but their production by, for example, rotating cutters can promote the formation of an emulsion by breaking up the oil components, which in turn worsens the separation.

In a fourth process step 4, the insect pulp is heated and stirred. In addition, the pH value is lowered.

The insect pulp resulting from the comminution can be stirred under heat for a period of time, preferably up to 3 hours, while being heated and/or kept at temperature. The preferred temperature in this step is 60-100° C. This process is also referred to as malaxation. The treatment of the insect pulp in this step can be carried out in a malaxeur.

Malaxation can preferably take place over a period of 60-130 minutes, particularly preferably 90-120 minutes, and is also preferably performed simultaneously with or immediately after acid addition.

Particularly preferably, the temperature during malaxation is in a range of 80-100° C., in particular below the boiling point of water, i.e., preferably 85-95° C. This preferably serves to terminate the enzyme activity and thereby prevent denaturation, since the pulpy substance obtained from insects otherwise quickly turns black on the surface.

The natural pH of insect larvae is typically in the slightly basic range. This is approximately pH=8.0 for the larva of the black soldier fly and pH=7.3 for the Mediterranean fruit fly larva.

According to the invention, the pH of the insect pulp is lowered to the acidic range at pH=1.5 to 6.5 after comminution by adding an acid.

This is done with the addition of an acid200and optionally with the addition of water100.

The addition of water100to the insect pulp depends on whether the insect pulp contains sufficient liquid of its own. If this is not the case, additional dilution water must be added to the malaxeur and/or in a subsequent process step 5 of a fractionation by means of a centrifuge.

Sufficient liquid is present if free liquid is visible under the oil phase in the insect rinse, during a spin test in the laboratory centrifuge.

The acid addition starts immediately, i.e., preferably within less than 10 minutes, particularly preferably within less than 5 minutes, after the comminution in process step 3.

The acid addition can preferably be completed within less than 5 minutes.

Preferably, a strong inorganic acid can be used as acid. This acid can be added as a dilute acid in aqueous form, preferably as a 1 molar acid or in even higher dilution, in order to avoid selective over acidification of the insect pulp during acid addition and to avoid dissociation effects.

As acid, hydrochloric acid HCl is particularly preferred, preferably as HCl solution.

The preferred adjusted pH of the insect pulp after acid addition is pH=2 to pH=4.5. Particularly preferably, the adjusted pH of the insect pulp is between pH=2 to pH=3.

In a fifth process step 5, the insect pulp is fractionated. The fractionation of insect larvae can be carried out by a separating device of the centrifugal separation technique.

The acidified and optionally malaxed insect pulp can now be separated into at least two fractions by means of a centrifuge, in particular by a decanter centrifuge.

Preferably, the decanter centrifuge can be operated at at least 3500 G. This shows that lower residual oil values in the solids can be achieved by prior malaxation and the addition of acid than without lowering the pH value and/or without malaxation.

The use of a decanter is preferred and particularly suitable for separating the solid phase. A 3-phase decanter or a 2-phase decanter can be used for this purpose.

During or following fractionation5, an alkali300may optionally be added to neutralize individual fractions, preferably the solid phase and/or the water phase.

Variations of the fractionation of process step 5 are shown inFIGS.2-4.

In process step 5, according toFIG.2, a single-stage fractionation5-1, by dividing the insect pulp into several fractions, can be carried out in a 3-phase decanter.

In this process, the insect pulp is divided into a fat phase600, a water phase400and a solid phase500. The terms “phase” and “fraction” are to be understood synonymously in the context of the present invention.

In process step 5, according toFIG.3, multi-stage fractionation5-2can be carried out in a 2-phase decanter as the first fractionation stage and a separator as the second fractionation stage.

The insect pulp is divided into a fatty aqueous phase700and a solid phase500. The aqueous fat-containing phase700can then be separated in a separator into a water phase400and a fat phase600.

Both the water phase400and the solid phase500may contain proteins of the insect larvae. The proteins may be present, for example, as protein curd suspended in the water of the water phase400.

In process step 5, according toFIG.4, a third fractionation5-3can also be carried out in multiple stages, also in a 2-phase decanter, followed by a subsequent treatment in an evaporator.

In this process, the insect pulp is divided into a fat phase600and a solids-containing aqueous phase800. A protein-rich solid phase500can then be produced from the aqueous solids-containing phase800by drying8.

The degreasing of the solid, can be influenced by the setting of the separator.

For this purpose, the fat content of the solid phase can optionally be measured and the speed and/or differential speed of the decanter can be adjusted if the fat content of the solid phase exceeds a predefined setpoint.

On the other hand, the way the insect pulp is made has an influence on the separation result.

Surprisingly, a shift in the pH of the insect pulp, shows a positive influence on the separation behavior, resulting in a particularly low residual fat content in the defatted solid (lower fat values).

Finally, in a sixth process step 6, the fractions can be further processed, e.g., by a drying step.

InFIG.2, further processing6of the fat phase600is carried out by fat polishing9. This can be done in a separator.

The water phase400may be subjected to drying7, in particular in an evaporator.

The solid phase500obtained in the fractionation5according toFIGS.2-4can be dried by a drying step 8, preferably in a spray and/or disk dryer or in a dry mill, in particular a so-called ultra-red mill.

FIG.5shows a table of a test result as evidence of the surprisingly better separation efficiency for the separation of fat from the other fractions due to the pretreatment steps described above.

The results give the residual fat content (values related to dry substance) in the solid.

The parameters for the spin test shown inFIG.5were as followsAcceleration=4800 g,Spinning time=1 to 2 minutes,Temperature of insect rinse and spinner more than 60° C., max. 95° C.,Starting material: flour beetle larvae (crushed)

FIG.5shows the retention time in tabular form, which is the time during which the insect pulp remains in the malaxeur.

Furthermore, the pH value of the insect pulp in the centrifugal test is listed in tabular form.

A reduction of the residual fat content of more than 25% compared to an insect pulp from mealybug larvae without pH treatment and with only a shorter residence time in the malaxeur can be seen.

Tests have shown that the prior killing of insects in combination with solids separation leads to a significant reduction in the “browning effect”, i.e., the brown discoloration after comminution.

This has been observed in particular with heating, especially boiling, e.g., in a hot water bath. Moreover, unlike e.g., freezing the insects, heating can be carried out in-line, i.e., without batch operation. This facilitates the procedural application and enables further automation of the processing procedure compared to freezing the insects.

Alternatively, heating can also be carried out by using a tubular heat exchanger, as shown inFIG.6. In this case, the insects are conveyed through the tube heat exchanger together with water, heated therein and killed.

As variants of heating for the purpose of killing, starting from the feedstock of the live insects, processing in a continuous process or an in-line process is suitable. This is a particular advantage in the case of heating compared to a much more costly freezing process.

The temperature input prior to comminution deactivates the insect's own enzymes already at the beginning of the process, which prevents or significantly reduces the discoloration of the comminuted insect mass (browning). This is a significant advantage for the subsequent use of the solid fraction.

If a medium such as water is used, the insects or larvae are also washed in this step, which can result in an additional increase in product quality.

This is shown inFIG.6. Here, water and live insects are fed by a pump15through a heat exchanger16. The water can be already preheated water, which is further heated within the heat exchanger16, e.g., a pipe heat exchanger. This results in the killing of insects by heating or boiling, analogous to a hot water bath.

The temperature of the water in which the insects are guided during killing is preferably more than 60° C., preferably 75-100° C.

The residence time in the heat exchanger until complete killing depends on the flow rate of the insects, the water temperature reached and the capacity of the heat exchanger. The time can be determined by calculation or by tests.

The killed uncrushed insects are then separated from the aqueous solution. This can preferably be done by sieving. InFIG.6, a sieving device in the form of a vibrating sieve19is provided for this purpose.

A collection tank20is arranged below the screening device19, and the liquid can be discharged from the collection tank by a pump21via a drain.

The heat exchanger16has a circuit for supplying a heat medium, e.g., hot water, with which the water/insect mixture in the heat exchanger can be indirectly heated. This circuit has at least one pump17and a second heat exchanger18, which can be operated, for example, with superheated steam. The killed uncrushed insects leave the screening device19and can be fed to a crushing device, e.g., a chopper, a press or a mill.

The entire process, including killing, can be carried out in continuous process control so that side reactions of the biological product are largely prevented or at least reduced.

The end product thus has fewer impurities and does not have to be cleaned up at great expense.

Although the invention has been illustrated and described in detail by way of preferred embodiments, the invention is not limited by the examples disclosed, and other variations can be derived from these by the person skilled in the art without leaving the scope of the invention. It is therefore clear that there is a plurality of possible variations. It is also clear that embodiments stated by way of example are only really examples that are not to be seen as limiting the scope, application possibilities or configuration of the invention in any way. In fact, the preceding description and the description of the figures enable the person skilled in the art to implement the exemplary embodiments in concrete manner, wherein, with the knowledge of the disclosed inventive concept, the person skilled in the art is able to undertake various changes, for example, with regard to the functioning or arrangement of individual elements stated in an exemplary embodiment without leaving the scope of the invention, which is defined by the claims and their legal equivalents, such as further explanations in the description.

REFERENCE SIGN

Process step 1 KillingProcess step 2 CleaningProcess step 3 ShreddingProcess step 4 MalaxationProcess step 5 Fractionation5-1first fractionation variant5-2second fractionation variant5-3Third fractionation variant6Further processing7Drying8Drying9Fat polishing15Pump16Heat exchanger17Pump18second heat exchanger19Vibrating screen20Collector tank21Pump100Water200Acid300Lye400Water phase500Solid phase600Fat phase700aqueous fatty phase800aqueous phase containing solids