Classifications

• • A—HUMAN NECESSITIES
  • A23—FOODS OR FOODSTUFFS; TREATMENT THEREOF, NOT COVERED BY OTHER CLASSES
  • A23K—FODDER
  • A23K50/00—Feeding-stuffs specially adapted for particular animals
  • A23K50/80—Feeding-stuffs specially adapted for particular animals for aquatic animals, e.g. fish, crustaceans or molluscs
• • A—HUMAN NECESSITIES
  • A23—FOODS OR FOODSTUFFS; TREATMENT THEREOF, NOT COVERED BY OTHER CLASSES
  • A23K—FODDER
  • A23K40/00—Shaping or working-up of animal feeding-stuffs
  • A23K40/30—Shaping or working-up of animal feeding-stuffs by encapsulating; by coating

Definitions

• the present invention relates to a quick-sinking fish feed in the form of pellets, a process for preparing the same, as well as a process for increasing the sinking speed of fish feed.
• Breeding of fish preferably salmonids, i.e. salmon of various kinds, takes place, after setting out, in open seawater.
• the fish is kept confined in large net bags, and foddering takes place by feed pellets being distri ⁇ ubbed at regular intervals on the marked-off surface of water.
• the fish eats the feed pretty soon after the dis ⁇ tribution, as a rule when the feed begins to sink.
• the size of the pellets depends on the size of the fish. Just after setting-out, in the so-called s olt stage, pellets having a diameter of about 2-3 mm are fed. The mesh size of the enclosing net is greater than the diameters of the pellets.
• Fish feed contains a large amount of protein and fat, since these nutritive substances are the best sources of energy for the fish.
• Fish feed may have, for instance, the following approxi ⁇ mate contents of nutritive substances:
• the ratio of protein to fat may vary depending on age and size of the fish to be fed.
• the fat content usually is slightly more than 30%.
• pellets the diameter of which is ⁇ 4 mm, have difficulty in sinking, especially in the cold time of the year when the density of water is at its maximum.
• the reason why the feed does not sink is its low intrinsic weight and the too high surface ten ⁇ sion. If the fish does not have time to catch the feed, the pellets will be moved by the waves of the sea through the meshes out into the free water. This is on the one hand an economic problem and, on the other hand, an envi ⁇ ronmental problem.
• NO Patent Specification 911,946 discloses a method of modulating the sedimentation speed of dry fish feed pellets by admixing to the pellets a surface-active agent, selected among certain fatty acid esters having an HLB value (hydrophilic-lipophilic balance) of not less than 12 so as to increase the sedimentation speed of the pellets and certain fatty acid esters having an HBL value of less than 8 to decrease the sedimentation speed of the pellets.
• a surface-active agent selected among certain fatty acid esters having an HLB value (hydrophilic-lipophilic balance) of not less than 12 so as to increase the sedimentation speed of the pellets and certain fatty acid esters having an HBL value of less than 8 to decrease the sedimentation speed of the pellets.
• the present invention provides a new and simple pro ⁇ cess of pronouncedly increasing the sinking speed of fish feed in the form of pellets of the above-mentioned type, whereby they are not affected by the waves of the sea.
• the problem is solved by coating the surface of fish feed pellets with a cold-water-soluble starch which has the capability of quickly absorbing cold water and swell ⁇ ing. This results in a quicker wetting of the surface, while the starch has the capability of forming "lumps of gel", which in turn increase the weight of the feed pel ⁇ let.
• the invention thus provides a quick-sinking fish feed in the form of pellets, which is characterised in that the surface of the pellet is coated with a cold- water-soluble starch.
• the invention also provides a process for increasing the sinking speed of fish feed in the form of pellets, said process being characterised in that the surface of the pellet is coated with a cold-water-soluble starch.
• a process for preparing a quick-sinking fish feed in the form of pellets is provided, a mixture of protein, fat, carbohydrates and optionally one or more additives selected from the group consisting of vitamins, minerals, colorants, being extruded to a pellet, said process being characterised in that the surface of the pellet is coated with a cold-water-soluble starch.
• Fish feed generally comprises protein in the form of e.g. fish meal, fat, carbohydrates and optionally other additives, selected among vitamins, minerals, colorants etc.
• the dry ingredients are mixed.
• part of the fat and water are added, such that the fat content during extrusion is between about 15 and 20% by weight and the water con ⁇ tent is slightly above 20% by weight.
• the material is subjected to vigorous mechanical working in combination with high pressure and high temperature. This treatment results in an expanded feed of high melt- ability.
• a nozzle At the end of the extruder there is arranged a nozzle, through which the material passes, and after that, a rotary cutter which cuts the material to a suit ⁇ able size. By varying the size of the nozzle and the speed of the cutter, the size of the feed pellets can be adapted to the fish to be fed.
• the pellets are dried, whereupon the remaining amount of fat is added, either by immersion in a hot oil bath or by spraying. Finally the pellets are cooled. So far, the preparation of the pellets according to the invention conforms with the preparation of pellets that are known hitherto.
• the surface of the pellets is to be coat- ed with a cold-water-soluble starch. This can take place either simultaneously with the completing supply of fat after extrusion, or in a separate stage after that.
• the actual coating operation can be carried out in different ways.
• coating the pellets are coated with a suspension of starch particles in oil.
• dusting in which the pellets are shaken together with particulate starch.
• starch When a plant produces starch molecules, these are successively stored around a centre, the so-called hilum, and form a firmly packed granule consisting of amorphous and crystalline regions.
• the molecular composition of the starch is heterogeneous.
• Normal starch is composed of two types of molecules. The one, amylose, is essentially linear and consists of 100-10000 glucose units. The other type of molecule, amylopectin, is considerably bigger and very much branched.
• Amylopectin consists of about 100,000 glucose units.
• Normal starch consists of about 20% amy ⁇ lose which forms the amorphous parts in the granule, and about 80% amylopectin which forms the crystalline regions.
• water and heat In order to make starch in granular form hydra- tise and swell, water and heat are required. The access to water is decisive of the temperature at which the starch dissolves.
• the starch In drum drying, the starch is preboiled, thereby swelling and being dissolved. Subsequently, the product is dried on drum driers to an amorphous powder. This powder can be ground down to various grain sizes and then has the property of swelling when treated with cold liquids.
• the amount of cold-water-soluble starch on the sur ⁇ face of the pellets can be within a range of 1-5%, pre- ferably 2-3%, based on the weight of the pellet.
• Feed pellets consisting of 60% fish meal (protein) 30% fat, 3% binder (starch) and the balance being vita ⁇ mins, minerals and colorants, were prepared by extrusion in conventional manner.
• a re-checking indicates an absorption of starch of about 1-2% based on the weight of the pellets.
• EXAMPLE 2 The same starting products as in Example 1 were used, but the starch was applied by so-called dusting.
• the sinking speed of pellets according to the inven ⁇ tion was examined in two different ways.
• Water-soluble starch was applied by the above-described coating tech- nique.
• the pellets had a size of 3 mm.
• the results ac ⁇ counted for are an average value from 10 measurements.
• pellets were applied very gently to the surface of a 4% salt solution.
• the temperature of the salt solu- tion is not allowed to exceed 7°C on the occasion of eva ⁇ luation.
• the pellets that are to be tested must be cold and are therefore taken directly from a refrigerator immediately before testing.
• use was made of the same type of pellets, however with no coating of starch.
• pellets that are to be tested must be cold and are therefore taken directly from a refrigerator immediately before testing.
• reference sample use was made of the same type of pellets, but with no coating of starch.

Landscapes

• Life Sciences & Earth Sciences (AREA)
• Chemical & Material Sciences (AREA)
• Polymers & Plastics (AREA)
• Zoology (AREA)
• Engineering & Computer Science (AREA)
• Food Science & Technology (AREA)
• Insects & Arthropods (AREA)
• Marine Sciences & Fisheries (AREA)
• Animal Husbandry (AREA)
• Birds (AREA)
• Fodder In General (AREA)
• Feed For Specific Animals (AREA)

Priority Applications (1)

Applications Claiming Priority (2)

Publications (1)

Family

ID=20400600

Family Applications (1)

Country Status (3)

Cited By (9)

Citations (2)

• 1995
  • 1995-12-15 SE SE9504489A patent/SE505003C2/sv not_active IP Right Cessation
• 1996
  • 1996-12-13 WO PCT/SE1996/001653 patent/WO1997022265A1/en active Application Filing
  • 1996-12-13 AU AU11555/97A patent/AU1155597A/en not_active Abandoned

Patent Citations (2)

Non-Patent Citations (1)

Also Published As

Similar Documents

Legal Events