According to a first aspect the present invention relates to a method for manufacturing a fish bait as stated in the preamble of claim 1. According to a further aspect the present invention relates to a fish bait produced by the method. During fishing it has been proven that the ability to catch fish, be it by angling or commercial fishing, can be increased considerably by adding flavourings, so-called attractants, which is attractive to fish. Such attractants may be used in association with both living as artificial bait.

Such agents are known among others from ZA 8206790 A, related to artificial bait comprising added flavourings and colourings to be attractive to fish. A mixture of grain, water and hydrogenated fats is included in the bait as an aromatizing substance. Hydrolysed vegetal protein and polyhydric alcohols used to increase the attractive effect on fish. Hydrolysed protein from marine resources is not discussed. The effect of the bait on one or more types of fish are also not disclosed or exemplified.

US 2003 066231A discloses a degradable artificial bait for fish based on natural, biodegradable components. Fish protein hydrolyzate, fish oil, fish meal, shellfish from the seabed, mussels from the seabed, fish powder, fruits, spices, garlic, garlic oil, neutral L-amino acids can be constituents of the bait. A particular effect of hydrolysed fish protein or other hydrolysed protein from marine resources as bait is not discussed. The effect of the bait to any fish species are neither discussed nor exemplified. U.S. Patent Nos. 4,704,286 A describes a fish bait with flavouring agent based on a water soluble polymer with slow solubility rate. The preferred polymer is polyvinyl alcohol having a

predetermined degree of hydrolysis of its ester groups, for achieving the desired rate of solubility. It may have the physical form of a sheet, comprising parallel slots. The flavouring agent consisting of gelatine hydrolyzate and beef extract, the gelatine hydrolyzate being made by pancreatic digestion of gelatine. Hydrolysed protein from marine resources is not discussed. The effect of the bait on one or more types of fish are neither disclosed nor exemplified.

US patent application 2004088901 describes an angling system consisting of a rod and reel, including fishing line, at least one artificial or natural bait and a controlled liberated fish attractant for application to said artificial or natural bait. Hydrolysed protein from marine resources is not referred to as fish attractant.

There is a considerable challenge to produce fish bait with inducements (attractants) which may be manufactured at a low cost, which are effective over time, which emits attractant with convenient rate to be effective immediately and which still retain efficacy over time, and which is not washed-out quickly in contact with water.

Objective

It is an object of the present invention to provide a bait that meets all the above challenges. The present invention

The above object is achieved by the present invention which according to a first aspect comprises a method as claimed in claim 1.

According to another aspect the invention comprises a fish bait as claimed in claim 17.

Preferred embodiments of the invention are disclosed by the dependent claims. By "slowly soluble (or degradable) in water" is meant that an exposed block of the polymeric material with a thickness of 2 cm will not be completely dissolved in saline water or fresh water in less than a minimum of 2 hours and more preferably 2 days. Preferably, such a block will be completely dissolved after less than about 2 months.

Further details of the invention with reference to the attached figures Figure 1 shows a schematic cross-section of parts of a first embodiment of an apparatus suitable for carrying out the method of the present invention.

Figure 2 shows a schematic cross-section of parts of a second embodiment of an apparatus suitable for carrying out the method of the present invention.

Figure 3 shows a schematic cross-section of parts of a third embodiment of an apparatus suitable for carrying out the method of the present invention.

Figure 4a and 4b show cross-sections of two variations of the fish bait prepared by one embodiment of the method of the present invention.

Figure 5a and 5b show cross-sections of two variations of the fish bait prepared according to another embodiment of the method of the present invention.

Figure 6a and 6b show cross-sections of two variations of the fish bait produced according to a third embodiment of the method of the present invention.

Figure 7a and 7b show cross sections of two variations of the fish bait prepared according to a fourth embodiment of the method of the present invention

Figure 8 shows another cross section of a variation of fish bait produced according to an embodiment of the method of the present invention. Figure 9 shows a cross section of a variant of the fish bait prepared by the embodiment which also resulted in the fish bait shown in Figure 4b.

Figure 1 shows schematically a cross-section of a type of extrusion head 11 suitable for use in carrying out the method of the present invention. The extrusion head 11 has two feed channels, a central tubular duct 12 and arranged around this a channel 13, both channels having a discharge end in a joining zone 14 in which the applied material is allowed to solidify using one or more mechanisms described in further detail below. To the right of the extruder head 11 a cross-section 15 of the fish bait leaving the extrusion head 11 is shown in the state it exhibits during solidification. It appears from the cross-sectional shape that the central channel 13 has the shape of a tube with circular cross section and that the channel 14 has the form an annular gap 13 coaxial with the channel.

Figure 2 shows schematically, like Figure 1, a cross-section of a type of extrusion head 21 with two supply channels, a central tubular channel 22 and around this a channel 23 is arranged, both of which having a discharge end in a joining zone 24 in which the applied material is allowed to solidify using one or more of the mechanisms described in more detail below. To the right of the extruder head 21 a cross-section 25 of the fish bait leaving the extrusion head 21 is shown in the state it exhibits during solidification. As indicated by the cross section 25, the cross section of the channels 22 and 23 are slightly irregular.

In general, the profile shown in Figure 2 has a first cross sectional side having a first shape and a first extension, while an opposite cross sectional side has a second shape and extension different from the first shape and extension such that a fluid flow across the bait will create a Bernoulli effect with an overpressure at one side and an under-pressure at the opposite side, similar to the flow of air around an air foil.

A person skilled in the art will understand that still other sectional profiles can be achieved by changing the cross section of the channels 22 or 23 or even only using interchangeable nozzles (not shown) where the liquid components are fed into the joining zone 24.

Figure 3 shows a third variant of an extrusion head 31 suitable for use in carrying out the method of the present invention. The extrusion head 31 is in principle similar to the variants shown in Figures 1 and 2. The cross-section of the channels 32 and 33 is not shown and may be similar to that in Figure 1 or in Figure 2 or they can also have other cross-sectional shapes. The

distinctiveness of the variant shown in Figure 3 is that there are supporting walls or a supporting casing for the material coming into the joining zone 34 and also a supporting casing in a subsequent stabilizing zone 37 downstream of the joining zone 34. Figure 3 also shows means 36 which surrounds the material in the joining zone and is suitable to speed up the solidification rate. The means 36 may consist of UV lamps which are suitable to accelerate the solidification rate of the material that solidifies by UV illumination, it can be means which are suitable to cool the material in the joining zone, means suitable to heat the material in the joining zone or means to remove volatile constituents from the joining zone 34, through application of a negative pressure in the zone. A combination of such agents may also be used, such as both means to heat the material and means to remove volatiles.

It is understood that in all variants shown in Figures 1-3, the bait is typically produced in the joining zone 14, 24, 34 as a longitudinally continuous extruded object which can subsequently be divided into desired lengths or thicknesses.

Figure 4a shows the cross-section of a product in the form of a fish bait 45 which is principally similar to cross-section 15 shown in Figure 1. The dark, circular component 46 includes the attractant suitable to lure fish, while the annular component 47 is a component with the ability to solidify. It is clearly preferred that the component 47 is able to solidify fairly rapidly, for example in seconds or a few minutes when subjected to conditions which favour solidification. Also component 46 may, in addition to the attractant, comprise material which solidifies. As shown in Figure 4a, the attractant is evenly distributed in the component 46 and there is little or no mixing of the components 46 and 47.

While the fish bait 45 leaves the joining zone as an endless "sausage", it is later typically sliced to discs in a direction across the direction of movement, that is, with a section as shown in Figure 4a.

In principle Figure 4b shows the same as Figure 4a, but with different cross-sectional shape of the fish bait. The desired cross-sectional shape can be achieved through the use of channels with such cross-sectional shape, or it can be achieved through the mechanical action of the fish bait (as shown in Figure 4a) immediately downstream of the joining zone, that is, before component 47 able to solidify, is completely solidified.

Figures 5a and 5b principally show the same as Figures 4A and 4B except that the attractant in this case does not exist as a homogeneous suspension but as discrete microcapsules distributed in component 56. Component 57 is the component with the ability to solidify under the given conditions. The advantage of the microcapsules may be to prevent premature leaching of attractant from the product, making it easier to control a slow release of attractant.

Figure 6a and 6b show a product variant where attractant, similar to the case shown in Figures 5a and 5b, is present as microcapsules, though here the final product is uniform over its entire cross- section, that is, there is no longer any boundary between the first and second component after the second component has solidified. This requires a slightly different type of equipment than the extruder shown in Figures 1-3. For example, a bundle of inner ducts 12, 22, 32 distributed within the cross section of one larger channel 13, 23, 33, may be used. Figures 7a and 7b show still another variant of the product resulting from the method of the present invention, by which the attractant is fed partly as a homogeneous suspension, partly in the form of microcapsules. The benefit of this may be to achieve both a fast, immediate release of attractant, while using micro capsules allows more reliable control with the duration of attractant available for release. Figure 8 shows a variant which has much in common with the variant shown in Figure 6b, but the concentration of attractant, decreases gradually from a high concentration near the cross-section centre to a lower concentration near the peripheral parts of the product's cross-section.

Figure 9 shows a cross section of a variant of the fish bait shown in Figure 4b. What is distinctive by the variant shown in Figure 9 is that along the length extension of the product a form of reinforcement 98 is arranged, adhering to the settable / solidified component 97. The

reinforcement 98 may in other embodiments enclose larger or smaller portions of the periphery of the product, the purpose of which being to provide greater physical strength to the bait, so that it will not easily disengage from the hook to which it is attached during fishing. The reinforcement 98 can be placed on the outside as shown in the figure, alternatively flush with the surface of the component 97 or within the component 97. The reinforcement can also be applied with a

"surplus" hanging free at the rear edge of the bait and which during movement through the water will flutter and make the bait appear more lifelike.

The reinforcement 98 is attached to at least part of the periphery of the polymer matrix of the bait before the latter is completely solidified, and is preferably fed consecutively with the liquid components to the joining zone 14, 24, thereby avoiding an extra step in the manufacturing process. The reinforcement 98 is typically made of a polymeric material in a form selected from foils, films, non-woven network, woven network. The material for the reinforcement 98 is preferably selected from paper, cardboard, silk, modified and unmodified cellulose, polyamide, polyester, polyvinyl alcohol, polyacrylic acid, cotton, viscose. Figure 10 shows a piece of bait placed on a hook during active fishing, the direction of movement being from right to left. The shape of the bait effects a flow along the surface of the bait in such a manner that there is a slight negative pressure on the upper side of the bait due to the curved shape that makes the water flowing over the bait on its upper side have a longer path to pass, thereby passing the bait with greater speed than the water which passes under the bait. Higher speed means lower pressure. Thus, the bait as a whole experiences a certain buoyancy in the water as a result of the movement, and will with increased speed move up to shallower water depths. More about the settable component

The liquid component with the ability to solidify typically comprises a polymer or polymer-forming monomers and / or oligomers. The specific chemistry of the component can be selected e.g. depending on the mechanism preferred for the solidification process. Relevant components for the component able to solidify include, but are not limited to, monomers, oligomers and / or polymers of: acryl, carbohydrates, saturated and unsaturated alcohols, saturated and unsaturated esters, carboxylic acids, epoxides and amines.

Examples of the solidification component and method for solidification

Solidification process and apparatus

The solidification process can be implemented in a variety of ways, depending primarily on the choice of polymer for the second liquid component. Thus, the solidification may e.g. be initiated through temperature increase, temperature decrease, evaporation of the solvent, UV illumination or by the use of peroxide.

The apparatus may advantageously comprise tubular members as shown in Figure 1-3. The tubular members can end in a joining zone, but it may be preferred that the outer tube continues a distance beyond the joining zone to facilitate stabilizing the combined materials during the solidification process.

In the joining zone, the material may for example be subjected to quenching to initiate solidification.

In another alternative UV light is used to solidify the polymer and thereby the entire combined material. In combination therewith transparent tubular bodies may be used at least in the joining zone.

The fish bait shown in Figures 6, 7 and 8 have no separation between first and second component after the bait is completed and solidified. The apparatus for producing bait in this form may include a tube with an opening corresponding to the cross section of the bait. Encapsulated attractant dispersed in at least one additional liquid component which has the ability to solidify, is squeezed or pumped through the tube followed by curing. The artisan will select in a per se known methods and materials for encapsulating the attractant. The skilled artisan will also choose thickness of the encapsulation so that the capsules are stable enough to withstand the pressure and shear forces during the manufacturing process and yet has the ability to release the attractant through the encapsulation during use of the bait in fishing. Capsules can be selected from millicapsules, microcapsules and nanocapsules and include capsule diameters typically from 50 nm to 20 mm.

In relation to all embodiments it is to be noted that the liquid component which contains attractant before joining with the other liquid component, may also contain materials that are able to solidify under the given conditions. This solidification process can take place under other conditions and with a different solidification rate than the solidification of the second component.

The shape and density of the bait may be significant in different contexts. A preferred variant of the fish bait of the present invention has an outer cross-sectional shape as shown by the Figures 4b, 5b, 6b, 7b, 8, 9, and 10. The essence of this form is to provide a buoyancy to the bait in the water during movement, by creating a local under-pressure above the bait and a local overpressure under the bait, according to Bernoulli's principle of correlation between pressure and movement. Furthermore, the density of the bait may be adjusted so that it is balanced with respect to the density of water. It is for example undesirable that the bait rests on the seabed if it is not moving, since in that case it will quickly be eaten by bottom fish, crabs or other marine organisms which one is not interested in catching. More about the attractant phase

Preparation of attractant from shrimps according to the invention

Shrimp shells from hand picked shrimps were delivered frozen in 10 kg blocks from Lyngen eker AS. The shell was stored at -20 ° C at Nofima in Troms0 before use.

The enzyme Alcalase (subtilisin) was delivered from Novozymes (Denmark) as liquid concentrate. Enzyme activity was measured by adding enzyme solution to substrate (8% dissolved casein). The reaction was stopped after 60 minutes by addition of trichloroacetic acid, and the remaining amino acids and peptides were measured spectrophotometric ally by Lowry's method. Proteolytic activity was measured before use to 60% of the maximum activity measured in freshly acquired Alcalase. The activity measurement was used as basis for the amount of added enzyme during the hydrolysis. Specific gravity of Alcalase was calculated to 1.14 g/ ml.

Pre-filtration was conducted with bag filter from Allied Filter Systems Ltd., England, of type WE100P2VWR (ΙΟΟμιη). The ultrafiltration was performed with two new polyether sulfone (PES) membrane filter of type PES2-383875AN-OX5A with a total filter surface area of 13.6 m ² and a pore size of 3000 Daltons. The membranes were provided by Due Milj0 AS, and flushed well with water in the filter system before use. Solids measurements during the production process were carried out with a Brix gauge, and temperature was measured with an electronic thermometer. Solids measurements of the final product were measured by drying at 105 °C until constant weight, and the amount of ash and organic material was determined by combustion at 550 °C to constant weight. Shrimp shells (300 kg) was thawed and tempered for two days by spreading 10 kg blocks in a cold room of 4 °C. The reactor being equipped with a stirrer was filled with hot water (about 80 °C) and mixed with shrimp shells (300 kg) to a total weight of 800 kg and a final temperature of 50 °C. Alcalase was added to the mixture to a final concentration of 1.14% (w/ w) (or 1% (v/ w)), and the reaction was allowed to proceed for 4 hours at a uniform temperature of 50 °C. After 4 hours of reaction the enzyme was inactivated by heating the mixture to 80 °C using indirect steam. Heating to 80 °C took a total of ca. 3 hours. The reactor was then covered and allowed to stand for about 16 hours. Then the water phase was drained down and separated from the undissolved shell through a coarse sieve at the bottom of the reactor. The temperature in the tank after resting for ca. 16 hours was 58 °C. A total of 550 kg water phase was drained off, having a dry matter (DM) content of 8% measured by a Brix meter.

The aqueous phase was filtered through bag filter (100 microns) to remove most particulate material before ultrafiltration. Only small amounts of solids were observed in the filters. The filtered aqueous phase was pumped into the feed tank of the ultrafiltration plant. The

temperature then was 50 °C and properly adjusted to the filters in the ultra filtration plant.

The water phase was ultra-filtered in a filter plant from GEA Liquid Processing Scandinavia AS (GLPs Combi Pilot Plant - Type ) with two polyether sulfone membranes as previously specified, with a pore size equivalent to 3,000 Dalton. The pressure difference over the filter surface (Ap) was maintained at about 1 bar, and the temperature was controlled to 50 °C. A pore size of 3000 Dalton means that all molecules with a molecular weight less than 3000 to pass through the filters, while larger, non hydrolysed proteins are held back. The phase that passes through the filters (permeate) was collected for further concentration by evaporation. The filtration rate through the filter was good and 530 kg of permeate was collected over a period of about 2.5 hours. Early in the filtration period the dry substance in the permeate was measured by Brix meter to 5%, while later in the filtration period it was measured to 7.5%. The concentrate (the retentate) is the fraction that did not pass through the filters but were concentrated in the filter facility. The retentate amounted to 23.5 kg and had a solids content of 11.8% at the end of filtration. The permeate (530 kg) was evaporated in an Alfa-Laval Convap 6x3 evaporator under a vacuum of 0.6 bar and a temperature of 60-65 °C. Evaporated water amounted to 112 kg/ h and the evaporation continued to a residual amount of 60 kg final product. The solids content in the final product was measured to 58% with Brix meter. The final product was stored in a cold room at 4 °C.

The example shows that the hydrolyzate according to the invention can be produced in industrially relevant amounts from shrimp as a raw material.

In a similar manner the attractant from mussels, braze or other marine raw materials may be prepared.

The attractant contained in the first liquid component can be of any type and nature, provided it does not adversely affect the mixing or solidification process. Attractants prepared through processes comprising hydrolysis of naturally occurring materials from marine raw materials can be particularly relevant. Preparation of such material exclusively by homogenization of the material is another option. Microcapsules

The attractant may in some embodiments be present as so-called microcapsules which are distributed or dispersed in the first liquid phase prior to the joining. The purpose of using capsules is to achieve a more controllable release of the attractant over time and the possibility to extend the time period during which attractant is released. The capsule walls must for this purpose form a barrier through which attractant can pass, but only at a slow rate, and/ or a barrier which gradually degrades in the current environment, fresh water or salt water. Increased pressure (depth of water) can also significantly affect the capsule stability and their ability to hold the attractant over time. Microcapsules may be prepared by a number of different techniques, dependent e.g. of the desired size ranges for the capsules. Not exhaustive techniques for preparing microcapsules include spray-drying, fluidized bed, so-called coacervation and "mechanical" capsule filling.

Important features and several applications of such techniques are disclosed in "Spray drying and encapsulation of omega-3 oils", Barrow, CJ et al., Woodhead Publishing Series in Food Science, Technology and Nutrition (2013), 252, 194-225;

"Microencapsulation of Anthocyanins by Natural Biopolymers: A Review", Mahdavi, SA et al., Drying Technology (2014), 32 (5), 509-518; "Encapsulation for preservation of functionality and targeted delivery of bioactive food components," de Vos, P. et al., International Dairy Journal (2010), 20 (4), 292-302; "Microencapsulation and its application", Harini, K. et al., Synthetic Fibres (2007), 36 (1), 21-28.

Microcapsules of smallest size is obtained by spray-drying, the capsules may then be down to 10 microns and more typically from about 10 to ca. 130 microns. When using the technique referred to as fluidized bed capsules of size from about 100 to 800 microns can be prepared; by coacervation capsules of size from about 100 microns to 3 mm can be prepared, and with filling machine capsules - typically with walls of gelatine - with size over 1 cm can be prepared.

Regardless of the size and type of capsules, it is important that the capsule material exhibits good adhesion to the polymer material of the solidifying component to avoid that the presence of capsules introduces a number of crack initiations in the fish bait which would reduce its mechanical stability. Other preferred factors

A preferred embodiment of the invention is a fish bait comprising at least 80 weight percent water. Such bait is quite similar to a natural bait such as mackerel or herring, is more rapidly dissolvable or degradable than fish baits with lower water content and is less expensive to manufacture.

Still another preferred embodiment of the invention is a fish bait comprising at least 5 weight percent of a material having a density less than 0.15 g / cm ³ . Such baits have lower density and thus a greater ability to lift from the sea floor than a bait without material having a density lower than 0.15 g/ cm ³ . Such a bait is less susceptible to being eaten by benthic animals, resulting in loss of bait.

The statement that at least one component with the ability to solidify is supplied; this means that in more than one component with the ability to solidify can be added separately or in mixture. For example, an additional component with the ability to solidify may be supplied via a further annular channel arranged outside and surrounding the first annular channel which is shown in Figures 1-3.

Joining the at least two components in the joining zone occurs in a way that involves co-extrusion of the components.

The solidified material is soluble or degradable in water, though preferably slowly soluble or alternatively slowly degradable, as explained above.

Also the first liquid component, i.e. the component comprising attractant may contain at least one constituent with the ability to solidify.