DE1034005B - Process for the production of fish meal and fish press water - Google Patents

Description

GERMAN

The present invention relates to a method which uses the so-called "cook-press method" for Improved production of fish meal, in particular made more technically effective and economical.

Mainly fatty fish, but also lean fish, are processed according to the " Koch-Press-Process ". According to the usual handling of this process, the raw material is first roughly crushed and then enters a heated double-jacketed pipe with a screw conveyor, the digester, in which the raw material is digested and sterilized with both indirect and direct steam. By subsequently pressing, mainly in screw presses, the material is dewatered to 45 to 50 ° / ₀ of dry substance and at the same time separating the major amount of oil. The solids are dried in dryers of various systems, while the resulting press water is recently freed of the coarser protein particles in continuously operating desludging and then the fish oil is separated from it by means of separators. The resulting when applying these processes press water containing an average of 6 to 8 ° / ₀ of dry substance and is supplied either directly to the fish meal drying apparatus and dried with the solids or else concentrated in vacuum Eindampfapparaturen or otherwise to 50% dry matter.

It has also already been proposed (Sharpless-Lassen method), acidify the resulting press water in order to denature the proteolytic enzymes and to precipitate with the egg white. By acidifying the press water, an exposure of the emulsified is at the same time Reached oil residues and the press water, which has been thickened to 50% dry matter, improves durability.

Furthermore, a method for obtaining animal body oils and fats is known, in which animal Egg white is adjusted to the isoelectric point after the cooking process. In this process, the Adjustment to the isoelectric point of the reaction product so only after the cooking process and sets a pre- previous treatment with electrolytes and surface-active substances or emulsifiers.

The Italian patent 373 002 finally made known a method according to which the crushed Raw fish by adding electrolytes containing hydrogen ions until the isoelectric is reached Point and then dewatered the pretreated fish raw material in hot air dryers will. A boiling and subsequent separation of the trane by pressing or centrifugation before drying does not take place. Press water is therefore not obtained after this procedure.

In contrast to the processes listed above, the present invention consists in the process for producing
of fish meal and fish press water

Applicant:

Wasag-Chemie Aktiengesellschaft,
Essen, Rolandstr. 9

Dr. Edgar Haase, Dr. Helmuth Nolte

and Dr. Lothar Reinhardt, Aschau (district of Mühldorf, Obb.),

have been named as inventors

Fish and / or fish waste in shredded or un-shredded Acids or acidic salts are added to the state before boiling to the extent that the pH value corresponds to the isoelectric point of the protein in question after cooking, but not in the direction Neutral point is exceeded. As has now been found, acidification to a ρπ value is therefore the Depending on the type of fish and the freshness of the fish, 0.2 to 1.2 pH units below the isoelectric point of protein in question is required. The, as described, acidified material is then cooked, for example in a heated double-jacketed pipe with a screw conveyor, and then in a Screw press or centrifuge pre-drained, with a large part of the Trane at the same time as the press water (Presstran) is removed. A part of the acidic press water produced is after desludging and de-oiling added to the raw material again, while another part either dried with the pressed solids or it is thickened in a vacuum evaporator.

The method according to the invention achieves considerable advantages, namely:

a) A better and easier separation between solid and liquid components, due to the fact that the Egg white remains in the de-swollen state during the entire cooking process. So it can be It is easier to squeeze cooked goods, especially to spin them off, with the mechanical degree of dewatering is increased.

b) By recycling the acidic press water and adding it to the raw material, a gradual and uniform swelling achieved, which in addition to the risk of acidification, the inclusion of oil particles is prevented.

809 560/54

c) In the press water, which is obtained by using the method described above, a Exposure of emulsified oil residues achieved or emulsification at all, d. H. during the cooking process, prevented. In contrast to this, there is considerable emulsification of the Trane in a press water that has not been acidified observed with finely divided and partly colloidally dissolved protein particles. This appearance is still due to the higher viscosity of the press water obtained by the usual process, their pH is around 7.0 to 7.5, favors. Are such press water also still in the following If the raw material is fed back, a further tranemulsification is the result, while the tranparation is carried out at the same time is made more difficult when separating.

d) The reaction mechanisms described under a) to c) result in a higher and better quality Oil yield achieved.

Below are some experimental results showing the advantages of the method of the invention can be clearly seen, in contrast to a working method according to which the raw material is only used up to Reaching the isoelectric point is acidified. Furthermore, in Example 6, the procedure was approximately according to US Pat. No. 1842,693, according to which there is no acidification, reproduced and with the method compared according to the invention. Absolutely the same starting material was used for experiments 1/2, 3/4, 5/6 used.

A comparison of the results shows that the press oil yields in tests 1 and 3 are comparative

material

Press water

Isoelectric point

this protein
Acidified on

Type of acid

Cooking (minutes) ...

pH after cooking

Drainage through.

Pressed oil yield,%

H ₂ O content of the
Egg white after
Throwing off, ° / o ■ · ·

10 kg of rotten herrings

4.01, sour

PH 5.1 Ph 4.0

H ₂ SO ₄ 10
5.0

Throwing off 14.2

50.4

10 kg starting material like 1

without

Ph 5.1 PH 5.1

H ₂ SO ₄ 10 6.0

Throwing off 13.5

53.6

10 kg fresh herring

4.0 1, acidic PH 5.2
Ph 4.6

H ₂ SO ₄
10
5.1

Throwing off 10.3

10 kg pegs
like 3

without

Ph 5.2
Ph 5.2

H ₂ SO ₄
10
5.9

Hurl off
9.8

52.0

10 kg of rotten herrings

4.01, sour

Ph 5.0 Ph 3.8

H ₂ SO ₄ 10
4.7

Throwing off 8.7

51.1

10 kg pegs like 5

4.01, ph 7.3

Ph 5.0

not

acidified

10 7.3

Spin 7.0

56.1

45

are higher than in tests 2 and 4, while the water content of the protein is lower in each case. Further the qualities of these two products are greatly improved.

Embodiment

Raw fish and / or their waste are chopped up in the usual way and placed in a mixing vessel or a Mixing screw intimately mixed with hot, desludged, deoiled and acidic press water (return). During the mixing process, the ρπ value of the goods is adjusted to a value using acid or acidic salts, which is 0.2 to 1.2 pn units below the isoelectric point of the protein in question. In places stronger acidity is to be avoided. The amount of press water to be added depends on the nature of the raw material.

Preferably 1000 kg of fatty fish are 250 to 4001 acidic, de-oiled and desludged press water added. The material pretreated in this way is then processed in a known manner sterilized or boiled and the oily press water separated by squeezing or spinning off.

The solids are then dried as usual, while the hot, oil-containing press water is used for sedimentation the protein particles are preferably pumped into insulated sedimentation vessels and left there for some time will. The supernatant, oil-containing press water is drawn off from the settling vessel and desludged in a known manner and de-oiled. However, it is not absolutely necessary to use sedimentation vessels; the Press water can also be desludged and de-oiled directly via desludging and separators.

The still acidic press water freed from oil and fatty substances is then pumped into an insulated storage vessel and from there, after removal above a conical bottom, advantageously the subsequent raw material added again. A certain proportion of this press water is taken from the conical end of the bottom of the vessel continuously for further processing, e.g. B. for thickening in multi-stage vacuum evaporators or but taken to dry with the solids.

Claims (5)

Claims 1. Process for the production of fish meal and fish press water from raw fish or their waste with the addition of electrolytes containing hydrogen ions, characterized in that the Fish material is so far mixed with acid or acidic salts before cooking that after the cooking process the isoelectric point is reached, but never exceeded in the direction of the neutral point, whereupon the material is cooked in the usual way, the oily press water is separated off and the solids to be dried. 2. The method according to claim 1, characterized in that the to be added before cooking Amount of acid or acidic salts measured in this way 5 6 is that the pH value of the goods by about 0.2 to water the cycle for the purpose of further processing, 1.2 pH units below the isoelectric point of e.g. B. in a vacuum evaporator, is removed, fish protein in question. 3. The method according to claims 1 and 2, thereby considered publications: characterized in that the resulting fish press water 5 German Patent Nos. 703 475, 722 431; wholly after desludging and oil removal or British Patent Nos. 612 554, 621 877; is partially added back to the raw material. U.S. Patent Nos. 2,534,640, 1,842,693; 4. The method according to claims 1 to 3, thereby Italian patent specification No. 373 002, referred to in characterized that an aliquot part of the Fischpreß- "Chemischen Zentralblatt", 1940, part II, p. 971. © 809 560/54 7.58