METHOD FOR PREPARING A POWDER OF BROWN MACROALGAE BY STIRRING AND A METHOD OF MANUFACTURING RIGID OBJECTS FROM SAID POWDER

Abstract

A method is provided for manufacturing a rigid object from a powder produced from shear stirred brown macroalgae so as to extract proteins, such as actin, from the brown macroalgae, the powder consisting of particles having an equivalent diameter smaller than or equal to 1.5 millimetres and having a residual moisture content smaller than or equal to 45%. The method includes thermo-compression of the powder in a mould, the powder being brought to a temperature between 50 and 100° C. and subjected to a pressure of between 150 and 4000 bars for 50 seconds to 45 minutes. Also provided is a method for preparing the powder.

Claims

1-14. (canceled)

15. A method for preparing a powder of brown and/or red macroalgae, for the manufacture of rigid objects, wherein the method comprises the following steps in that order: harvesting said brown and/or red macroalgae; shear stirring said macroalgae in a tank a rate of at least 4 rpm, so as to extract proteins, such as actin, from said macroalgae, wherein said shear stirring is carried out at least partially under vacuum; drying said stirred macroalgae, so as to obtain stirred and dried macroalgae having a residual moisture content smaller than or equal to 45%; and grinding said stirred and dried macroalgae, so as to obtain a powder of macroalgae.

16. The method for preparing a powder of brown and/or red macroalgae according to claim 15, wherein, during said drying step, the drying temperature of said stirred macroalgae ranges between 30 and 50° C.

17. The method for preparing a powder of brown and/or red macroalgae according to claim 16, wherein, during said drying step, the drying temperature of said stirred macroalgae ranges between 30 and 45° C.

18. The method for preparing a powder of brown and/or red macroalgae according to claim 15, wherein the step of shear stirring of said macroalgae is performed for a time that ranges between 6 and 24 hours.

19. The method for preparing a powder of brown and/or red macroalgae according to claim 15, wherein particles of said powder of macroalgae have an equivalent diameter smaller than or equal to 1.5 millimetres.

20. The method for preparing a powder of brown and/or red macroalgae according to claim 15, wherein said drying step comprises a step of compacting said macroalgae in the form of a plurality of granules of volume between 0.1 and 1 cm.sup.3.

21. The method for preparing a powder of brown and/or red macroalgae according to claim 20, wherein said compaction step comprises a step of adding to said macroalgae, macroalgae treated with a weak acid.

22. The method for preparing a powder of brown and/or red macroalgae according to claim 21, wherein the weak acid comprises at least one of acetic acid, citric acid, or an acid diluted in water.

23. The method for preparing a powder of brown and/or red macroalgae according to claim 15, wherein said step of shear stirring is carried out under vacuum throughout its duration.

24. The method for preparing a powder of brown and/or red macroalgae according to claim 15, wherein said step of stirring comprises a step of adding to said macroalgae an additive belonging to the group consisting of: water; a dye: a coloured pigment; an odour absorbent; an odorant agent; albumin.

25. The method for preparing a powder of brown and/or red macroalgae according to claim 24, wherein said dye or said coloured pigments, said odour absorbent and albumin are added in respective proportions of 0.05 to 0.1%, 1 to 3.5% and/or 0.2 to 1%.

26. The method for preparing a powder of brown and/or red macroalgae according to claim 15, wherein said stirring rate ranges between 4 and 6 rotations per minute.

27. The method for preparing a powder of brown and/or red macroalgae according to claim 15, wherein, in said stirring step, at least 2% actin contained in said macroalgae, is extracted.

28. The method for preparing a powder of brown and/or red macroalgae according to claim 27, wherein in said stirring step, at least 5% actin contained in said macroalgae, is extracted.

29. The method for preparing a powder of brown and/or red macroalgae according to claim 15, wherein said brown macroalgae are chosen from brown algae of the order laminariales or of the order fucales.

30. The method for preparing a powder of brown and/or red macroalgae according to claim 29, wherein said brown macroalgae are selected from thelaminaria digitata, ascophyllum nodosum species and the genus fucus species.

31. The method of preparing a powder of brown and/or red macroalgae according to claim 15, wherein the residual moisture content of said powder is greater than or equal to 7%.

32. A method of manufacturing a rigid object at least partially from brown macroalgae, wherein the method comprises the following steps in that order: shear stirring said macroalgae in a tank a rate of at least 4 rpm, so as to extract proteins from said macroalgae, wherein said shear stirring is carried out at least partially under vacuum; drying said stirred macroalgae so as to obtain stirred and dried macroalgae having a residual moisture content smaller than or equal to 45%; grinding said stirred and dried macroalgae so as to obtain a powder of macroalgae; and thermo-compression of said powder in a mould, said powder being brought to a temperature between 50 and 100° C. and subjected to a pressure of between 150 and 4000 bars for 50 seconds to 45 minutes.

33. The method for manufacturing a rigid object according to claim 32, wherein in said thermo-compression, said powder is brought to a temperature between 60° C. and 100° C.

34. The method for manufacturing a rigid object according to claim 32, further comprising at least one partial step of applying a water-repellent lacquer on a surface of the thermo-compressed powder.

35. The method for manufacturing a rigid object according to claim 32, wherein the shear stirring is performed so as to extract actin from said macroalgae.

Description

5. LIST OF FIGURES

[0053] Other features and advantages of the invention will become more evident on reading the following description of one particular embodiment of the invention, given by way of illustrative and non-limiting example only, and with the appended drawings among which: [0054] FIG. 1 is a schematic diagrammatic representation of the steps of an exemplary method for preparing a powder from brown macroalgae according to the invention; [0055] FIG. 2 is a view of a powder obtained by the preparation method shown with reference to FIG. 1; [0056] FIG. 3 shows a thermo-compression press used to form a funerary urn from brown macroalgae powder; [0057] FIG. 4 is a schematic view of a half-shell of a funerary urn manufactured in thermo-compressing a powder of brown macroalgae using the press shown in reference to FIG. 3.

6. DESCRIPTION OF A DETAILED EXAMPLE OF THE INVENTION

[0058] FIG. 1 shows in the form a block-diagram the steps of an example of embodiment of a method for preparing a powder intended for the manufacture of rigid manufactured articles according to the invention, from a mixture of laminaria digitata and ascophyllum nodosum, also known as black seaweed.

[0059] In other embodiments of the invention, it may be envisaged to prepare a powder only from laminaria digitata or ascophyllum nodosum or any other kind of brown algae alone or mixed.

[0060] After harvesting laminaria digitata and ascophyllum nodosum on the high seas, the latter are methoded on a production line of a powder preparation plant where they are washed in a first steps to remove sand and the shells interlaced in the algal thalli (step 11).

[0061] About 70% in weight of laminaria digitata and 30% in weight of ascophyllum nodosum are then poured into a mixing tank, in which they are shear stirred under continuous vacuum for 14 hours at a rate of 6 rpm (step 12). During this stirring step 12, 0.03% w/w of a natural dye is added gradually during a step 121 and 1.2% w/w of activated carbon fines is added to mask the odour emanating from them.

[0062] At the end of step 12, a block of macroalgae is obtained, the appearance of which reveals that they are agglomerated with one another by an actin gel.

[0063] To the macroalgae extracted from the mixing tank is then added 8% in mass of a waste obtained from an alginate production plant, consisting of a residue of low-acid-treated brown macroalgae from which alginates are extracted (step 13).

[0064] In a step 14, the macroalgae extracted from the mixing tank and the macroalgae treated with the weak acid are mixed by means of an auger (step 141) and this mixture is compacted in an annular matrix granulate press, in the form of substantially cylindrical granules of about 6 millimetres and 10 to 20 millimetres in height (step 142).

[0065] In a variant of this particular embodiment of the invention, the macroalgae extracted from the mixing tank can be directly compacted in the form of granules, without adding macroalgae treated with the weak acid.

[0066] The granules thus obtained are then dried in an induction heating tunnel or by heat transfer fluid for 6 hours at a temperature of 46° C. (step 15).

[0067] In variants of this particular embodiment of the invention, it may be provided to dry the granules for 1 to 15 hours depending on whether a static or dynamic drying mode is used.

[0068] At the exit of the drying tunnel, the dried granules are conveyed by a belt conveyor to a hammer mill in which the granules are ground in the form of a powder with a grain size of 1 ±0.3 mm (step 16). FIG. 2 is a top view of an open pouch of powder 21 obtained by the preparation method according to the invention.

[0069] Each production line of the plant thus enables to continuously prepare approximately 3 tons of powder per hour at an attractive cost.

[0070] In a particular embodiment of the invention, the residual moisture content of said powder is about 39%.

[0071] The powder thus obtained can be used directly to prepare manufactured articles.

[0072] Illustrated in FIG. 3 is a thermo-compression press 31 developing a pressure of 300 kg/cm .sup.2 for manufacturing the half-shells of a 180 mm-diameter substantially hemispherical funerary urn from a powder of brown macroalgae.

[0073] As can be seen in FIG. 3, the press 31 has a piston head equipped with a cast heated to 98° C. by induction. For the sake of mastering the manufacturing method, the temperature of the cast of the piston is regulated.

[0074] The powder is dosed automatically by a suction flow in the lower mould 32 brought to a maximum regulated temperature of 98° C.

[0075] In this example, 500 g of powder are metered into the mould and a force of 12.5 tons is exerted on the powder with the piston head for a cycle time of 45 minutes, so as to raise the powder temperature to about 70° C.

[0076] A funeral half-urn 41 is obtained with a mass of about 490 g and a density of 1.58, illustrated schematically in FIG. 4 in a perspective view.

[0077] A water repellent lacquer is then sprayed onto the surface of the funeral half-urn to render it insensitive to moisture.

[0078] In a subsequent step, the surface of the urn is decorated by pad printing or by digital printing.

[0079] It will be noted that, advantageously, when using an imprint tool, the temperature of the casts is chosen between 75 and 110° C.

[0080] It can also be envisaged without departing from the scope of the invention, to apply the successive steps for preparing a powder of a mixture of brown and red macroalgae or of a powder of red macroalgae:

harvesting the macroalgae;
shear stirring of said macroalgae in a tank a rate of at least 4 rpm for 6 to 24 hours, so as to extract proteins, such as actin, from said macroalgae;
drying said macroalgae stirred at a temperature ranging between 30° C. and 50° C., preferably between 30 and 45° C., so as to obtain stirred and dried macroalgae having a residual moisture content smaller than or equal to 45%;
grinding said stirred and dried macroalgae, so to get a macroalgae powder whose particles have an equivalent diameter smaller than or equal to 1.5 millimetres.

[0081] An exemplary embodiment remedies the shortcomings of the state of the art mentioned above.

[0082] More precisely, An exemplary embodiment provides a raw material totally or at least predominantly produced from brown macroalgae which can be used to manufacture rigid manufactured articles.

[0083] A particular embodiment provides this raw material in the form of a powder of constant quality and homogeneous properties.

[0084] An exemplary embodiment provides a technique for producing manufactured articles from brown macroalgae which is simple to implement and reliable.

[0085] An exemplary embodiment provides such a manufacturing technique whose operating cost is reduced.

[0086] An exemplary embodiment also upgrades an algal raw material taken from the open sea or cultivated on floating ropes.

[0087] Although the present disclosure has been described with reference to one or more examples, workers skilled in the art will recognize that changes may be made in form and detail without departing from the scope of the disclosure and/or the appended claims.