FEED FOR AQUATIC SPECIES WITH A STABLE SOFT AND ELASTIC TEXTURE

Abstract

Extruded, formulated, complete feed for aquatic species, said formulated, complete feed comprising: at least one non-hydrolysed protein source; at least one fat source; fibers inherent in at least one raw material; optionally at least one carbohydrate containing source; a vitamin additive; a mineral additive; water; a binder comprising at least partly an edible, starch containing, tuberous-originating thickening agent; a hydrolysed plant protein source; and a plasticizer,
and said formulated, complete feed comprises a moisture content from about 12.5% to about 25% (w/w) of the complete feed.

A method for production of the feed is disclosed as well.

Claims

1. An extruded, formulated, complete feed for aquatic species, comprising: (a) at least one non-hydrolysed protein; (b) at least one fat source; (c) fibers; (d) a vitamin additive; (e) a mineral additive; (f) water; (g) a binder comprising at least partly an edible, starch containing, tuberous-originating thickening agent; (h) a hydrolysed plant protein source; and (i) a plasticizer, wherein the feed has a moisture content from about 12.5% to about 25% (w/w) of the complete feed.

2. The feed according to claim 1, comprising from about 5% to about 9% (w/w) of an edible, starch containing, tuberous-originating thickening agent of the complete feed.

3. The feed according to claim 1, wherein the hydrolysed plant protein is a hydrolysed plant protein with a degree of hydrolysis from about 3% to about 25%.

4. The feed according to claim 1, comprising from about 5% to about 15% (w/w) hydrolysed plant protein of the complete feed.

5. The feed according to claim 1, wherein the hydrolysed plant protein comprises hydrolysed wheat gluten.

6. The feed according to claim 1, comprising from about 1.5% to about 5% (w/w) plasticizer of the complete feed.

7. The feed according to claim 6, wherein the plasticizer comprises glycerol.

8. The feed according to claim 1, having a moisture content from about 14% to about 20% (w/w) of the complete feed.

9. The feed according to claim 1, comprising from about 40% to about 60% (w/w) crude protein content of the complete feed.

10. The feed according to claim 1, comprising from about 15% to about 35% (w/w) of crude fat content of the complete feed.

11. The feed according to claim 1, having a hardness less than 1000 g mm.sup.−1 as measured by diametral compression using a texture-analyser fitted with a 50 kg load cell and a 5 mm diameter spherical cylinder, a trigger of 10 g, compressing a horizontally placed feed pellet at a pre-test speed of 2 mm s.sup.−1 and at a constant test speed of 2 mm s.sup.−1 to achieve 35 g of force, and a post-test speed to 10 mm s.sup.−1 and a break sensitivity to 10 g and record a strength-time graph by a computer.

12. The feed according to claim 1, having a hardness less than 1000 g mm.sup.−1 as measured by diametral compression using a texture-analyser fitted with a 50 kg load cell and a 25 mm diameter spherical cylinder, a trigger of 5 g, compressing a horizontally placed feed pellet at a pre-test speed of 2 mm s.sup.−1 and at a constant test speed of 2 mm s.sup.−1 to achieve 40% compression, and a post-test speed to 10 mm s.sup.−1, recording a force-strain graph by a computer and calculate Gradient=Force (g)/Strain (%) at a first peak of the force.

13. A method of producing a feed for aquatic species according to claim 1, comprising: (i) providing: (a) at least one non-hydrolysed protein; (b) at least one fat source; (c) fibers; (d) a vitamin additive; (e) a mineral additive; (f) water; (g) a binder comprising at least partly an edible, starch containing, tuberous-originating thickening agent; (h) a hydrolysed plant protein source; and (i) a plasticizer, (ii) mixing at least the at least one non-hydrolysed protein source, fibers, vitamin additive, mineral additive, binder comprising at least partly an edible, starch containing, tuberous-originating thickening agent, hydrolysed plant protein source, and optionally, the at least one fat source, plasticizer, and water; (iii) optionally, feeding the mixture of (ii) into a pre-conditioner; (iv) optionally, adding the plasticizer and/or the at least one fat source to the pre-conditioner; (v) optionally, adding steam and/or water to the pre-conditioner; (vi) feeding the, optionally preconditioned, mixture to a cooking extruder; (vii) optionally, adding the plasticizer and/or the at least one fat source to the cooking extruder; (viii) optionally, adding water and/or steam to the mixture of step vii); (ix) making an extrudate, and optionally cutting the extrudate into feed pellets; and (x) optionally, adding the at least one fat source to the feed pellets by sub-atmospheric coating.

14. A method for production of the formulated, complete feed according to claim 1, comprising: (i) providing the non-hydrolysed protein source, optional carbohydrate containing source, vitamin additive, mineral additive, edible, starch containing, tuberous-originating thickening agent, and hydrolysed plant protein source; (ii) mixing the materials provided in (i); (iii) feeding the mixture of (ii) into a pre-conditioner; (iv) optionally adding the plasticizer to the pre-conditioner; (v) adding steam to the pre-conditioner and optionally adding water to the pre-conditioner; (vi) feeding the heated materials from the pre-conditioner to a cooking extruder; (vii) optionally adding the plasticizer to the cooking extruder; (viii) optionally adding moisture to the mixture of (vii) to the extruder; (ix) making an extrudate with an oil absorbing capacity of at least 10% (w/w); and (x) adding the fat source to the extrudate in a sub-atmospheric operated coating apparatus.

15. A method of feeding an aquatic species, comprising administering to the aquatic species a feed according to claim 1.

16. The method according to claim 15, wherein the aquatic species is selected from the group consisting of tuna, salmonids, basses, tilapia, cleaner fish, cod fish, flat fish such as flounders, soles, turbot, plaice, and halibut, catfish, pike and pickerel, carps, breams such as sea bream, shrimp, prawns, crabs, lobsters, and crawfish.

Description

[0103] In the following are described examples of preferred embodiments and analytical results are illustrated in the accompanying drawings, wherein:

[0104] FIG. 1 shows a comparison of texture between a 9 mm diameter standard Atlantic salmon feed and an 8.5 mm soft and elastic feed according to the invention, x-axis: strain (%), y-axis: force (g);

[0105] FIG. 2 shows in the same way as FIG. 1 a comparison of texture between a 17 mm diameter standard turbot feed and a 20 mm soft and elastic feed according to the invention;

[0106] FIG. 3 shows a comparison of several standard fish feed (hard pellets) and soft and elastic feeds according to the invention as “gradient” (=force(g)/strain (%)) as a function of pellet size;

[0107] FIG. 4 shows a comparison of texture between five different 8.5 mm diameter feeds according to the invention, stored for up to six months at 25° C. and 75% RH;

[0108] FIG. 5 shows results from a growth trial with young bluefin tuna (T. orientalis) comparing feeding with raw forage fish and a feed according to the invention;

[0109] FIG. 6A-B Panel A shows samples of a diet 1 feed (according to the invention); panel B shows a feed pellet after manually squeezing four or five times;

[0110] FIG. 7A-B Panel A shows samples of a diet 2 feed (without wheat gluten hydrolysate); panel B shows a feed pellet after manually squeezing four or five times; and

[0111] FIG. 8A-B Panel A shows samples of a diet 3 feed (without glycerol); panel B shows a feed pellet after manually squeezing four or five times.

[0112] Feed Texture Analysing Method #1

[0113] Strength at rupture (hardness) was measured by diametral compression using a Texture-Analyser (TA XT2, Model 1000 R; SMS Stable Micro Systems, Blackdown Rural Industries, Surrey, UK), fitted with a 50 kg load cell. Once the trigger of 10 g is attained, the probe proceeds to compress the sample. Analyses were performed using a 5 mm diameter spherical stainless-steel cylinder (P/5S, Stable Micro Systems) by pressing the cylinder onto the horizontally placed pellet at a pre-test speed of 2 mm s.sup.−1 and a constant test speed of 2 mm s.sup.−1 to achieve 35 g of force. The post-test speed was set to 10 mm s.sup.−1 while break sensitivity was set to 10 g. The strength-time graphs were recorded by a computer and analysed using the Texture Exponent for Windows (version 6.1.7.0, Stable Micro Systems), and strength at rupture was recorded on ten pellets. Strength was reported as the average value of ten pellets.

[0114] Feed Texture Analysing Method #2

[0115] Strength at rupture (hardness) and elasticity were measured by diametral compression using the same Texture-Analyser as in Method #1, fitted with a 50 kg load cell. Once the trigger of 5 g is attained, the probe proceeds to compress the sample. Analyses were performed using a 25 mm diameter spherical stainless-steel cylinder (P/25, Stable Micro Systems) by pressing the cylinder onto the horizontally placed pellet at pre-test speed of 2 mm s.sup.−1 and a constant test speed of 2 mm s.sup.−1 to achieve 40% compression. The post-test speed was set to 10 mm s-1. The force-strain (%) graphs were recorded by a computer, analysed and reported as “gradient”, i.e. Gradient=Force (g)/Strain (%). Strength at rupture was reported as the average value of ten pellets.

EXAMPLES

[0116] Standard formulated dry pellets of 9 and 22 mm in diameter presented in the examples were manufactured in the ordinary way by extrusion as is well known by those skilled in the art. Total moisture content was adjusted to about 7-8% by drying after extrusion. Soft and elastic fish feed pellets suitable for feeding tuna according to the invention were prepared separately as described below.

[0117] The formulated fish feeds presented in the examples meet the theoretical nutritional requirements for Atlantic Bluefin Tuna (T. thynnus). The formulations of the 8.5 mm, 25 mm and 35 mm in diameter tuna feeds are given in table 1A. Tuna feeds of 8.5 mm correspond to the standard formulated dry pellets of 9 mm, and tuna feed of 25 mm corresponds to the standard formulated dry pellets of 22 mm, as these are comparable feed sizes.

[0118] Production of Fish Feed Suitable for Feeding Tuna

[0119] A first 8.5 mm diameter fish feed according to the invention was produced as follows: The dry ingredients were pre-mixed in a vertical mixer and ground in a Dinnissen 30 kW hammer mill (Dinnissen, Sevenum, The Netherlands), with a screen size of 0.75 mm. The ingredients were then mixed in a Dinnissen horizontal ribbon mixer (500LTR) for 7 min. The feed mash was conditioned in a differential diameter conditioner (DDC 2; Wenger Manufacturing, Sabetha, Kans., USA) and extruded in a Wenger X-85 single screw extruder with a screw diameter of 85 mm. The ingredients were extruded as described, yielding extrudates with a diameter of 8.5 mm and a length of approximately 9 mm. The knife rotation speed was adjusted according to the specified length of the extrudates.

[0120] The drying temperature was set to 25° C. and the product was dried for just 5 min in a Wenger Series III horizontal 3-zones dryer. Typically, at these conditions, the product will lose only about 1% moisture of its nominal weight and therefore the whole process can be seen as a “no drying process”. Subsequently, the pellets obtained were coated with oil in a Forberg 6-I vacuum coater (Forberg, Oslo, Norway). The total moisture addition to the extrusion process, i.e. added to the preconditioner and/or to the extruder barrel was calculated in such a way to give 15% total moisture content in the finished product, considering almost no loss of water during drying and accounting for the loss of moisture during extruder die “flash off” as well as coating. Actual moisture addition is shown in table 2.

[0121] A second 8.5 mm diameter fish feed according to the invention was produced as described above but extruded in a Wenger TX-57 twin screw extruder. The barrel of the extruder was 57 mm in diameter and the length-to-diameter ratio was 17.5:1. The extruder barrel consisted of four head sections, with each section jacketed to permit either steam heating (Sections 1-4) or water cooling (Sections 2-4). Temperature control of the second, third and fourth sections was achieved by balancing the heating and cooling power input. The ingredients were extruded as described, yielding extrudates with a diameter of approximately 8.5 mm and a length of approximately 9.5 mm. The knife rotation speed was adjusted according to the specified length of the extrudates.

[0122] The obtained fish feed was dried in a Wenger Series III horizontal 3-zones dryer to approximately 850 g kg.sup.−1 dry matter.

[0123] Subsequently, the obtained first 8.5 mm fish feed and the second 8.5 mm fish feed were coated with fish oil in a Forberg 60-I vacuum coater.

[0124] A 25 mm diameter fish feed according to the invention was produced on a commercial extruder (Wenger, X-175 Single screw extruder). This fish feed has been prepared using the same procedure as described for the 8.5 mm diameter fish feed production. The process parameters can be found in table 2.

TABLE-US-00001 TABLE 1A Formulations of fish feeds according to the invention Examples/Pellet size (mm) Ex. 1/ Ex. 2/ Ex. 4/ Ex. 5/ Ingredient (kg) 8.5 25 35 35 Water (added) 0.07 7.88 8.44 8.44 Glycerol 3.36 2.20 2.20 2.20 Potato starch 7.02 8.00 7.00 7.00 Wheat gluten hydrolysate 7.07 7.5 14.50 14.50 Vital wheat gluten 3.46 5.50 Krill meal 1.00 3.00 3.00 3.00 Fish meal 56.51 47.99 36.05 36.05 Fish protein hydrolysate 5.01 5.00 5.00 Fish oil 11.51 14.47 21.38 21.38 Minerals & vitamin mix 4.98 2.46 2.28 2.28 Salt (NaCl) 1.00 Calcium propionate 0.15 0.15

TABLE-US-00002 TABLE 1B Composition by NIR analysis of some fish feed according to the invention Examples/Pellet size (mm) Ex. 1/ Ex. 2/ Ex. 4/ Main constituents (%) 8.5 25 35 Moisture 15.6 13.9 13.3 Protein 49.3 41.8 40.5 Fat 18.4 21.5 23.8 Ash 8.1 8.8 8.7 Other* 8.6 14 13.7 *Glycerol, carbohydrates, fibres

TABLE-US-00003 TABLE 2 Extruder process parameters Examples/Pellet size (mm) Ex. 1/ Ex. 3/ Ex. 2/ Ex. 4/ Ex. 5/ Process parameter 8.5 8.5 25 35 35 Capacity feed mix (kg h.sup.−1) 120 150 4319 200 2938 Steam added to pre-conditioner 6.5 6 7.2 6 5.7 (%) Water added to pre-conditioner 10 13 8.8 9.5 6.6 (%) Temperature pre-conditioner 85 74 89 71 90 (° C.) Steam added to extruder (%) 4.1 Water added to extruder (%) 0 0 0 0 0 Glycerol added to pre- 3.7 3.3 2.4 2.8 2.7 conditioner (%) Process oil (%) 1 3.6 0.6 3 7.4 Extruder barrel temp. (° C.)* ≈90 ≈90 ≈90 ≈100 ≈100 Revolution of screws (rpm) 361 578 371 321 353 Die orifice diameter (mm) 7 6.5 19.5 31 25.1 Bulk density after extruder (g/l) 540 540 459 529 *Material within the extruder barrel is at least 20 K warmer than the extruder barrel

TABLE-US-00004 TABLE 3 Drying parameters Examples/Pellet size (mm) Ex. 1/ Ex. 3/ Ex. 2/ Ex. 4/ Ex. 5/ Drying parameter 8.5 8.5 25 35 35 Temperature section 1 (° C.) 25 40 40 Temperature section 2 (° C.) 25 38 40 Temperature section 3 (° C.) 25 36 40 Total drying time (min) 5 13 Dryer batch time (s) 40 40 40 Dryer fans 1-3 Off Off Dryer heaters 1-3 Off Off

[0125] Texture Analysis

[0126] The accepted threshold to consider an extruded product soft is 1000 g/mm force using the Feed texture analysing method #1 in combination with a shape of the curve from the Feed texture analysing method #2 as shown in FIGS. 1 and 2. The product is soft if the force is below 1000 g/mm.

[0127] In some cases, a standard feed particle can be below the threshold value of 1000 g/mm using the Feed texture analysing method #1 depending for instance on the feed ingredients used, but even than the shape of the curve from the Feed texture analysing method #2 will remain the same as shown in FIGS. 1 and 2.

[0128] The results of texture analysis may be presented in a different format as shown in FIG. 3. Each pair of values “force (g)” and “strain (%)” at the first peak of force is given as “gradient” (=force/strain). “Gradient” is shown as a function of pellet size and plotted for each measured fish feed pellet. In case there is no first peak of force, see e.g. FIG. 1 for the soft and elastic fish feed, the pair of values are the endpoint of the graph, i.e. 40% compression has been reached without the pellet cracking.

Example 1

[0129] A first 8.5 mm diameter fish feed according to the invention was produced as described in tables 2 and 3 and according to the recipe shown in table 1A. Actual content of main constituents is shown in table 1B. The 8.5 mm feed was compared to a standard, i.e. commercial, 9 mm diameter Atlantic salmon fish feed.

[0130] Texture of the feeds were analysed as described by Feed texture analysing methods #1 and #2. Results for the Feed texture analysing method #2 are shown in FIG. 1.

[0131] The shape of the salmon feed curve presented in FIG. 1 is typical for the standard hard and brittle extruded feed particles. The maximum force value, which represents hardness or the first cracking point of the feed particle, occurs rather early, i.e. short penetration distance of the probe, which results in a steep peek. After the first crack, the force does not get straightway to zero as the feed particle still shows some resistance while it is steadily broken down into smaller particles.

[0132] On the other hand, the soft and elastic fish feed particle according to the invention demonstrates a completely different shape of curve. This is typical for a soft and elastic sample. The long distance the probe compresses the feed particle without breaking it or reaching the first peak, indicates that the feed particle has not broken. This is an indication of elasticity of the pellet. Short distance of penetration before the first peak indicates a brittle feed particle whereas a long distance of penetration before rupture indicates a more elastic feed particle. In addition, the maximum breaking force of the elastic fish feed particle is significantly lower compared to the Atlantic salmon feed particle.

[0133] Hardness value of the first 8.5 mm elastic fish feed measured by Feed texture analysing method #1 was 516 g mm.sup.−1. The hardness of the 9 mm Atlantic salmon feed, i.e. comparable size, was 3778 g mm.sup.−1.

[0134] The elastic fish feed demonstrated standard quality criteria such as sinking speed, oil absorption capacity and durability according to commercial guidelines established by the Applicant (data not presented).

Example 2

[0135] A 25 mm diameter fish feed according to the invention was produced as described in tables 2 and 3 and according to the recipe shown in table 1A. Actual content of main ingredients is shown in table 1B. The 25 mm diameter feed was compared to a standard, i.e. commercial, 22 mm diameter turbot fish feed.

[0136] Texture of the feeds were analysed as described by Feed texture analysing methods #1 and #2. Results for the Feed texture analysing method #2 are shown in FIG. 2.

[0137] The standard turbot feed shows no or very little resistance before the first crack, i.e. maximum force value, and therefore the force drops immediately to zero which results in a steep peak.

[0138] Hardness value of a 22 mm standard turbot feed was 3874 g mm.sup.−1, while the hardness of the 25 mm tuna feed according to the invention was 416 g mm.sup.−1.

[0139] The elastic fish feed demonstrated standard quality criteria such as sinking speed, oil absorption capacity and durability according to commercial guidelines established by the Applicant (data not presented).

[0140] Comparison of the curves of FIGS. 1 and 2 shows that increasing the feed particle size from 8-9 mm to about 20 mm is not changing the texture of the feed particles according to the invention.

[0141] As shown in FIG. 3, pellets according to the invention in a “pellet size”−“gradient” diagram follows a linear distribution as a function of pellet size. The distribution may follow the formula: gradient=33.5×(pellet size)−235. In contrast, hard pellets of known art may follow the formula: gradient=202×(pellet size)−1364.

Example 3

[0142] Five different feeds of 8.5 mm diameter according to the invention was produced as described in tables 2 and 3 and according to the recipes shown in table 4. The purpose was to evaluate shelf life of the feeds. Varying amounts of calcium propionate was added to the recipes as preservative. The feeds were stored at a temperature of 25° C. and at 75% RH (relative humidity) during the whole storage period.

TABLE-US-00005 TABLE 4 Formulations of fish feeds of Example 3 Samples Ingredient (kg) 1 2 3 4 5 Water (added) 10.11 10.11 10.11 10.11 10.11 Glycerol* 3.02 3.02 3.02 3.02 3.02 Potato starch 6.31 6.31 6.31 6.31 6.31 Wheat gluten hydrolysate 8.50 8.50 8.50 8.50 8.50 Vital wheat gluten 4.96 4.96 4.96 4.96 4.96 Krill meal 0.90 0.90 0.90 0.90 0.90 Fish meal 47.08 46.98 46.88 46.73 46.73 Fish protein hydrolysate 4.51 4.51 4.51 4.51 4.31 Fish oil 10.35 10.35 10.35 10.35 10.35 Minerals & vitamin mix 4.27 4.27 4.27 4.27 4.27 Calcium propionate 0 0.15 0.25 0.35 0.55

[0143] Sampling was performed after 1 month, 3 months and 6 months of storage. Samples were analysed for microbial quality, i.e. mold, aerobic bacteria, anaerobic bacteria and Clostridium perfringens, and for hardness. Results for hardness are shown in FIG. 4.

[0144] In general, the microbiological results show that it is possible to store the product for six months without an anti-molding agent addition (results not shown). Moreover, the texture was acceptable for all the products produced in this trial after six months of storage.

[0145] Some hardening was observed between the one month samples and the three month samples. The hardness then remained stable between three and six months of storage. All samples remained soft and elastic during storage as all samples demonstrated a hardness of less than 1000 g mm.sup.−1 after six months of storage.

Example 4

[0146] A 35 mm diameter fish feed according to the invention was produced on a pilot scale as described in tables 2 and 3 and according to the recipe shown in table 1A. Actual content of main ingredients is shown in table 1B.

[0147] The measured hardness of the product was 443 g mm.sup.−1. In addition, standard quality criteria for this type of feed were according to the Applicant's commercial guidelines (data not shown).

Example 5

[0148] A 35 mm feed for tuna according to the invention was produced in the same way as described for the 8.5 mm tuna feed. For comparison and to check influence of scale of process, a second single-screw extruder (X-175, Wenger Manufacturing with a screw diameter of 175 mm) was used to produce 35 mm new tuna feed.

[0149] The 35 mm diameter fish feed was produced as described in tables 2 and 3 and according to the recipe shown in table 1A.

[0150] The feed was soft and elastic. In addition, standard quality criteria for this type of feed were according to the Applicant's commercial guidelines (data not shown).

Example 6

[0151] Young bluefin tuna (T. orientalis) at approximately 6 kg body weight were caught by purse seine in 2017 and transferred to four sea cages in a commercial fish farm close to Wakayama (W. Japan). Each cage was stocked with approximately 850 fish that were fed raw forage fish mainly consisting of Japanese sardine (Sardinops melanostictus), Japanese horse mackerel (Trachurus japonicas), chub mackerel (Scomber japonicas) and/or blue mackerel (S. australasicus) to apparent satiation. The fish in two cages were weaned to eat a SOFT EP diet according to the present invention over a period of one month before onset of the growth trial. The growth trial compared SOFT EP with raw forage fish and started on Dec. 11, 2017. The trial lasted for 4 months till Apr. 10, 2018. The ambient water temperature decreased from 19° C. at the start of the trial to 14-15° C. in February-March before increasing again towards 17° C. at the end of the trial. Fish were fed to apparent satiation and development in body size/growth was followed using an AQ1 camera system every month. Survival during the trial was high (≥99%) and independent of diet. Fish fed the SOFT EP grew significantly better (approximately 30% increase from initial body weight) compared to fish fed the raw forage fish (approximately 5% increase) (FIG. 6). Especially during the period with declining water temperature and low water temperature, SOFT EP supported better growth than raw forage fish. Feed conversion ratio (FCR) calculated as feed dry matter (kg) used per kg weight gain of fish, were also better for SOFT EP (3.5 and 6.0) compared to feeding raw forage fish (5.3 and 11.2).

Example 7

[0152] The following three diets were prepared by means of cooking extrusion into pellets of 20 mm diameter and assessed for elasticity and braking strength. Diet 1 contained both wheat gluten hydrolysate and glycerol, whereas diet 2 lacked wheat gluten hydrolysate and diet 3 lacked glycerol.

TABLE-US-00006 Diets Diet 1 Diet 2 Diet 3 Water 8.6 8.6 8.6 Glycerol to extrusion 3 3 0 Potato starch 7 7 7 Wheat gluten hydrolysate 7.5 0 7.5 Vital wheat gluten 7 7 7 Krill meal 0.9 0.9 0.9 Fish meal 42.8 50.3 45.8 Fish Protein Hydrolysate 5 5 5 Fishoil 14.7 14.7 14.7 Min&Vit premix 3.5 3.5 3.5

[0153] The pellets of diet 1 had a smooth surface and shiny appearance. The pellets were soft and elastic (FIG. 6A) and could easily be squeezed four to five times without rupturing (FIG. 6B).

[0154] In contrast, pellets of diet 2 and 3 had torn edges, rough cutting surface, marked protrusions and grooves (FIGS. 7A and 8A, respectively). These pellets were not elastic. The pellets cracked/ruptured already after squeezing them once. After four to five times squeezing, they were ruptured considerably and started to fall apart (FIGS. 7B and 8B, respectively).

[0155] Thus, both the plant protein hydrolysate and the plasticizer were required to obtain soft and elastic pellets as taught herein.

[0156] It should be noted that the above-mentioned embodiments illustrate rather than limit the invention, and that those skilled in the art will be able to design many alternative embodiments without departing from the scope of the appended claims. In the claims, any reference signs placed between parentheses shall not be construed as limiting the claim. Use of the verb “comprise” and its conjugations does not exclude the presence of elements or steps other than those stated in a claim. The article “a” or “an” preceding an element does not exclude the presence of a plurality of such elements.

[0157] The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage.