MX2008000620A - Method for preparing plasticised wheat gluten compositions for petfood and pet treat applications - Google Patents

Abstract

A method for manufacturing plasticised gluten compositions for pet food and pet treat applications, the method comprising the steps of:mixing at least gluten and a plasticiser wherein the mixing equipment is set to a value below 500C and the SME (Specific Mechanical Energy) applied to the mix is less than 600 kj/kg, wherein the gluten content is between 20 and 85%by weight wherein the plasticiser content is less than 40%by weight. The invention also relates to the use of plasticised gluten for the manufacture of a chewy pet food having a high breaking force.

Description

METHOD FOR PREPARING PLASTICIZED WHEAT GLUTEN COMPOSITIONS FOR PET AND FOOD APPLICATIONS SANDWICHES FOR PETS FIELD OF THE INVENTION The subject of this application are improved methods for preparing plastified wheat gluten vital compositions that have improved flexibility with respect to processing, in pet food applications or pet snacks, such as a pet chew meal.

STATE OF THE ART The plastified compositions of wheat gluten for food of humans and animals have been previously described in the prior art. Gluten is a protein that has been described as a high molecular weight polymer (Rigley, et al., 1996, Glutenin polymers-Nature's largest proteins, Royal Australian Chemical Institute: North Melbourne, Australia, p.316). in which the glutenin subunits are linked by the binding of the disulphide between the chains of the cysteine residues (Graveland, A., et al., 1985. A model for the molecular structure of the glutenins from wheat flour J. Cereal Sci. Vol. 3: 1-6).

In addition, it has been previously documented that gluten is considered a glassy polymer having a glass transition temperature that may depend on the plasticizer content and the pressure (Hoseney, RC, et al., 1986. Wheat gluten: a glassy polymer, Cereal Chem. 63: 285-286). The glass transition temperature of wheat gluten plastified with water, glycerol or sorbitol has also been studied (Gontard, N. et al., 1999. Glass transition of wheat gluten Plasticized with water, glycerol or sorbitol J. Agri e. Food Chem. 47: 538-543). Gluten can also form films, as described by Gontard, N. et al., In the Journal of Science, 1993, 58, p. 203-211. In addition, the viscosity of the gluten will not decrease with heating, but instead will stop the level or increase due to cross-linking reactions (Attenburrow et al., Rheological properties of wheat gluten, 1990. J. Cereal Sci. 12 : 1-14).

The knowledge of cross-linking reactions is important to understand the thermoplastic extrusion process. The formation of the final molecular network formed with gluten and glycerol (as a plasticizer) involves the dissociation and non-unfolding of the macromolecules, which allows them to recombine and cross-link through specific bonds (redi, A. , et al., 1999. Rheological properties of gluten plasticized with glycerol: dependence on temperature, glycerol content and mixing conditions, Rheol. Acta 38: 311-320). Therefore, it is known that glycerol has a plasticizing effect on gluten.

The combination of gluten with glycerol has been used in a variety of foods. In US Pat. No. 6,007,858, glycerol is used as a humectant to preserve gluten. In this patent, 15% of the wheat gluten was mixed with glycerol or maltodextrin to prepare tamale rolls.

WO 0008944 describes a composition for the preparation of chewing gums. Plasticized proteinaceous materials are described which are prepared by means of a batch process or are prepared continuously by mixing the protein with a plasticizer. Batch processing is done using a Brabender torque rheometer (high shear sample mixing). The continuous plasticization is carried out using a conical extruder with two rotation screws per count. The typical processing conditions used for this are a processing temperature of 70 ° C-100 ° C, and a processing torque of 500 to 3000 mg. Among the different protein materials, zein and wheat gluten are cited as the preferred protein materials. The materials are used as an ingredient to prepare non-tacky chewing gum. Publication WO 02/41701 and EP 1 066 759 Al also disclose the use of gluten in the manufacture of chewable compositions and chewable products.

Stable retort food pieces comprising gluten are described in US Pat. No. 5,456,934. Furthermore, a dry pet food having a meat-like structure made of protein adhesives, such as alkali-modified wheat gluten, is known from GB 1 433 976.

The purpose of US Pat. No. 6,818,245 is to provide a digestible, degradable gluten composition that can be stored for a prolonged period of time without degradation, and used as a gum base for chewing gums. This objective was carried out by developing life wheat gluten in a non-aqueous medium (i.e., a medium having an aw <0.8). In a typical preparation, the vital wheat gluten and a plasticizer are mixed together for 5 minutes to one hour at a temperature between 50 ° C and 90 ° C, typically 58 ° C, in a mixer until the 75th is obtained. % of maximum torque. The mixing must be stopped when 75% of the torque value is reached, so that there is no loss in the mechanical properties of the gluten mixture, eg. ex. , allow the gluten to unfold, and restore its interactions, i.e., the H bridges, the hydrophobic and ionic bonds, the bridges of sulfur and the cross-links. The ratio of vital wheat gluten compared to a "non-aqueous" medium is 20:80 and 60:40. In most of the examples cited in this patent, 50% vital wheat gluten mixed with 50% glycerol is used.

Another work on the behavior of vital wheat gluten plastified with glycerol was carried out by A. Redi., S. Guilbert, et al. The results of this work were published in several scientific journals, such as "Rheological properties of gluten plasticised with glycerol: dependence on temperature, glycerol content and mixing conditions", Rheological Acta, Vol. 38: 311-320 (1999). This Article describes the use of a Haake batch mixer to provide specific mechanical energy (SME) to a mixture of gluten and glycerol for 4.5 to 32.5 minutes to determine the effects of torque on batch mixing. The glycerol content varied from 30-60% and the higher glycerol levels required higher SME values. The SME ratio varied from 1000 to 2000 KJ / Kg. In addition, the operating temperature was maintained at 80 ° C.

The publications Les Cahiers de Rhéologie (1997), p. 339-347, and J. Agrie. Food Chem (1999), Vol. 47. p. 538-543 refer to the preparation of wheat gluten compositions plasticized with glycerol using torque to develop a dough. With this it is observed that, as the torque increases, the gluten / glycerol mixture, which originally shows the consistency of a sand / water mixture, changes its consistency to that of a plastic and very sticky cohesive mass. When the maximum torque is exceeded, the appearance of the gluten / glycerol mass changes to that of a fairly glossy, non-sticky and very elastic material. The temperature change in the gluten / glycerol mixtures during mixing is characterized by a sigmoidal curve with the point of change in maximum torque.

It is also noted that, to a certain degree, these temperature increases result in irreversible changes of the plasticized material, whereby the final product obtained may no longer be suitable for the above-mentioned applications. The ratio between gluten and plasticizer in these applications varies between 75:25 and 60:40.

In Cereal Chemistry, 1999, vol. 76, p. 361-369, by the same authors, the extrusion of wheat gluten plastified with glycerol is discussed. This publication concludes that extrusion at low drum temperatures (<60 ° C) is limited, due to the increase in viscosity. The increase in viscosity causes the die pressure and torque to increase beyond the extruder limits. It is also observed that the specific mechanical energy input (SME) is at least 638 kJ / kg, as described in Table I of the same publication.

In order to obtain plastified wheat gluten compositions, a common denominator in the prior art cited above is the use of dough development conditions or shear mixing conditions that result in increases in the torque and temperature of the composition during The procedure.

Because wheat gluten becomes more reactive as a result of the above, the viscosity of the plasticizer material also develops.

As a result of these conditions, the products obtained by means of these prior art methods show numerous defects, such as: diminished transformation possibilities: the irreversible changes occurring in the plasticized mass, which, if it is required to give this mass a new form, must go through a heat treatment by which the temperature that is now required will exceed the temperature of the previous step of the procedure, and / or a relatively low extensibility: due to the autocatalytic process, the plasticized mass can become more and more rigid (elongation reduced to rupture, reduced flexibility), while increasing the resistance to tearing, - and / or increased plasticizer content: this compensates to a certain extent the loss in the possibilities of transformation and provides some flexibility with respect to the mechanical properties.

As a result of the aforementioned shortcomings, the degree of incorporation of the plastified wheat gluten of the prior art in food, feed and non-food applications is limited.

In addition, US Patent 2,586,675 discloses a method for making a chewing gum that uses gluten and glycerin to prevent the gum from hardening and drying out. The gum is kept in an elastic and chewable state, combining 50-80% gluten with 15-30% glycerin, a sweet substance, and allowing the mixture to mature for 1 to 6 hours for the plasticizer to penetrate the gluten. However, the process for obtaining this plastic material is very long and difficult to implement in an industrial environment.

In view of the prior art cited above, the problem to be solved is therefore to provide an improved method for preparing plasticized gluten compositions for application in pet food and in pet snacks.

BRIEF DESCRIPTION OF THE INVENTION According to the foregoing, the objective is solved according to the independent claims. Dependent claims also develop the central idea.

Therefore, in a first aspect, the present invention proposes a method for manufacturing plasticized gluten compositions for food applications for macotas or pet snacks. The method comprises the steps of: - mixing at least the gluten and a plasticizer - where the mixing equipment is adjusted to a value below 50 ° C and the SME (specific mechanical energy) applied to the mixture is less than 600 kJ / kg, - where the gluten content is between 20 and 85% by weight, - where the plasticizer content is less than 40% by weight.

In a second aspect, a pet food is provided that is obtainable by the method of the invention.

A pet food or a chewable pet food can be obtained by mixing at least gluten and a plasticizer by applying an SME of less than 250 kJ / kg, where the plasticizer content is below 40% by weight of the total mixing mass, which falls under another aspect of the invention.

The invention provides, in another aspect, a chewable dog food sandwich, comprising plasticized gluten which is composed of 55-75 parts by weight of gluten and 35-20 parts by weight of a plasticizer, the sandwich having a maximum value of elongation of 200 to 750%, and a chewing time, when chewed by dogs, of at least 15 minutes.

Another aspect of the present invention provides a chewable pet food sandwich, comprising plasticized gluten with a maximum breaking force on the scale of 200 to 850 N.

DETAILED DESCRIPTION OF THE INVENTION Preferably, the pet food or pet snack compositions of the composition have a low plasticizer content (eg, below 40% by weight of the plasticized material), whereby the plasticized material shows good properties of cohesion, high extensibility and easy transformation properties.

The origin of the gluten is preferably wheat or other cereals. Modified gluten, e.g. ex. , gluten that has gone through physical, chemical or enzymatic treatment.

The cohesion properties are thus reflected by means of stress values at rupture and extensibility by means of the values of elongation at rupture.

The properties of easy transformation are reflected by the possibility of forming / reforming the plasticized material at temperatures below 70 ° C.

This has now been achieved by means of the method according to the present invention.

The invention proposes a process for preparing wheat gluten compositions for pet food applications or pet snacks, composed of 20-85 parts by weight of vital wheat gluten and less than 40 parts by weight of a plasticizer, where: - wheat gluten and 1 plasticizer can be fed in a continuous mixing device, and - the components can be mixed and homogenized at relatively low temperatures and with a low plasticizer content, where the specific mechanical energy input (SME) is lower at 600 kJ / kg.

Therefore, the present invention proposes a method for manufacturing plasticized gluten compositions for pet food or pet food applications, the method comprising the steps of: - mixing at least gluten and a plasticizer - where the mixing equipment is adjusts to a value below 50 ° C and the SME (Specific Mechanical Energy) applied to the mixture is less than 600 kJ / kg, - where the gluten content is between 20 and 85% by weight - where the content of Plasticizer is less than 40% by weight.

Preferably, the SME is less than 200 kJ / kg. In a more preferred embodiment, mixing is performed with an SME of more than 75 kJ / kg, preferably more than 150 kJ / kg, most preferably, of 150 kJ / k.

The mixing is preferably carried out continuously, using a continuous mixing device.

E.g . , mixing and homogenization are carried out by means of a mixing screw configuration that allows mixing and homogenization.

In the method of the invention, the temperature of the equipment is set at a temperature below 50 ° C, preferably between -10 ° C and 45 ° C, more preferably between -10 ° C and 0 ° C.

The advantage of these low temperature conditions and / or low mechanical energy conditions is that the gluten molecules do not unfold. The less the gluten molecules unfold without breaking the intermolecular and intramolecular disulfide bonds, the elasticity is maintained so that the final state of the molecule is still elastic.

The plasticizer can be selected from the group of polyhydroxy alcohols, starch hydrolysates, lower fatty acids (from C2 to C12), hydroxyalkylamines, hydroxy acids, polycarboxylic acids, urea and mixtures thereof.

The polyhydroxy alcohols are selected from glycerol, ethylene glycol, propylene glycol, diethylene glycol, triethylene glycol, sugar alcohols, any mixtures thereof and may contain up to 30% by weight of water. The sugar alcohols are selected from among glucose, fructose, sucrose, sorbitol, maltitol, xylitol, mannitol, lactitol, erythritol, isomalt, hydrogenated starch hydrolysates and mixtures thereof.

Preferred polyhydroxy alcohols used are selected from glycerol, ethylene glycol, propylene glycol, diethylene glycol and triethylene glycol, with glycerol being most preferred.

The hydroxy acids may be selected from lactic acid, malic acid or tartaric acid, gluconic acid and salts thereof.

The polycarboxylic acids are selected from succinic acid, adipic acid, citric acid, isocitric acid, glucaric acid and salts thereof.

These plasticizers can be used separately or in combinations.

In the process of the invention, the plasticizer content is preferably between 15 and 40%. More preferably, the plasticizer content is below 35%, even more preferably, it is below 30%, still more preferably it is below 25%. Most preferably, the plasticizer content is more than 20%.

The wheat gluten material as such may show some variability in the rheological properties, as illustrated by the alveograph measurements, or by means of Brabender plastgraph measurements. These variations are due to the origins of the wheat of raw material used, to variations in the conditions of the harvest, and to variations in the processing conditions.

In the process of the invention, the gluten content is preferably between 60 and 85% by weight.

Suitable continuous mixers can be selected from continuous screw mixers, continuous ribbon mixers and extruders equipped with a screw configuration that allows mixing without substantial input of mechanical energy. These types of screw configurations are known to the person skilled in the art.

In a preferred embodiment, an extruder containing the required screw configuration is used. When an extruder is used, it is advantageous to adjust the drum and the screw to a temperature not exceeding 60 ° C, preferably 50 ° C, in the section of the mixing screw. At the same time, the temperature of the materials leaving the continuous mixing unit will not exceed 90 ° C, preferably 80 ° C. It should be noted that the temperature applied to the drum is intended to limit the increase in temperature.

In another advantageous embodiment, the wheat gluten plasticizer material is composed of 65-75 parts by weight of vital wheat gluten and 35-25 parts by weight of plasticizer.

In a preferred embodiment the plasticizer is glycerol. This glycerol can contain up to 20% water.

Depending on the conditions of the process in combination with the amounts of ingredients used, a variety of suitable plasticizing materials can be obtained. A pet food according to the invention can be obtained by the method described herein. The properties of these compositions can vary from homogeneous, plastic and deformable to hard, elastic as rubber, and highly extensible.

The plasticized compositions leaving the continuous mixing device can be used as such or further processed and formatted. Additional processing and forming can be performed, e.g. ex. , by compression molding, calendering, transformation by rolling and / or microwave treatment.

Compared with the above-mentioned prior art compositions, less extreme process conditions (temperature and specific mechanical energy input, SME) are required to obtain products with well-formed rubber elasticity. At the same time, the intermediate and final materials may comprise less plasticizer and more gluten protein. A reduced plasticizer content may be advantageous in numerous food and / or feed applications in which a very high content of low PM polyol plasticizer is not desirable (eg, pet foods, chewable confectionery, imitations of meat, etc.). The desirable content of low molecular weight polyols such as glycerol and propylene glycol in these applications is typically below 25% by weight, preferably below 20% by weight, of the final compositions.

In another aspect of the invention, the compositions can be prepared by combining a range of products with the plastified wheat gluten prepared according to the process of the invention. These products may be added in an amount of between 0.1-40% by weight of the composition, during or after the preparation step of the plastified wheat gluten. More preferably, these products can be added in an amount of between 0.5-25% and more preferably between 1-15% by weight of the composition.

These products can be selected from among the byproducts obtained during the processing of agricultural or forest raw materials, polysaccharides and derivatives thereof, other proteins of vegetable or animal origin, mineral compounds, biomass, fermented materials, and / or mixtures thereof.

The agricultural by-products may comprise by-products of wet or dry milling of cereals, in particular corn and wheat, from the processing of oleaginous materials, including, but not limited to, soybean, sunflower or rapeseed, from the processing of other major crops such like, but not limited to, sugar cane, sugar beet, potato or tapioca.

Polysaccharides include, but are not limited to, starches in a native or modified form, cellulose and derivatives thereof, beta glucans, inulin-type polysaccharides, pectins, arabinoxylans, plant gums or microbial gums.

Other proteins include, but are not limited to, for example, concentrates and soy isolates, legume proteins, casein and derivatives thereof, wheat proteins, fish proteins, or animal proteins, including plasma proteins.

In addition, additives may also be incorporated, such as coloring or flavoring additives, amino acids, peptides, vitamins, stabilizers, and / or emulsifiers.

In a particular embodiment of the invention, chewable pet food snacks are prepared comprising the plasticized wheat gluten obtained by the process of the invention. These compositions may also contain up to 20% of additional ingredients belonging to the products described in the preceding paragraphs.

The materials thus obtained are characterized by their high flexibility in combination with long chewing times.

The invention proposes, for the first time, the use of plasticized gluten to produce a chewable pet food sandwich. This is surprising, since a chewable pet food sandwich has physical properties that are completely different from those of a chewing gum. It has been especially surprising that the high breaking force required for pet chewing has been achieved using plasticized gluten.

Therefore, the invention provides a chewable pet food or pet food, which is obtained by mixing at least gluten and a plasticizer by applying an SME of less than 250 kJ / kg, where the plasticizer content is below 40% by weight of the total mass mixed.

The physical parameters that differentiate a chewing gum from a pet chew such as a chewable pet snack are, for example: The flexibility of the chewable snacks of the invention is reflected in the elongation of a standard piece when subjected to a standardized tearing operation. Maximum elongation values of at least 200%, preferably at least 300% and more preferably at least 400% are obtained.

A chewable dog food snack according to the present invention comprises plasticized gluten composed of 55-75 parts by weight of gluten and 35-20 parts by weight of a plasticiser-faced, and has a maximum elongation value of 200 to 750% and a chewing time, when chewed by dogs, of at least 15 minutes.

Preferably, the dog food sandwich comprising plastified gluten is composed of 65-75 parts by weight of gluten and 35-25 parts by weight of a plasticizer, the sandwich having a maximum elongation value of 200 to 650% and a chewing time, when chewed by dogs, of at least 20 minutes.

According to a preferred embodiment, the plasticizer used is glycerol.

According to another aspect of the invention, there is provided a chewable pet food sandwich comprising plasticized gluten, which has a maximum breaking strength on the scale of 200 to 850 N. Preferably, the dog food sandwich has a strength maximum breaking on the scale of 200 to 600 N, more preferably on the scale of 200 to 400 N, even more preferably on the scale of 200 to 350 N.

The pet food sandwich of the invention may comprise plasticized gluten which is comprised of 50-75 parts by weight of vital wheat gluten and 50-25 parts by weight of a plasticizer.

Preferably, the plasticized gluten in the pet food sandwich is comprised of 55-75 parts by weight of vital wheat gluten and 35-20 parts by weight of a plasticizer.

According to another embodiment, the plasticized gluten can be composed of 60-70 parts by weight of vital wheat gluten and 40-30 parts by weight of a plasticizer.

The pet food or pet sandwich of the invention has a maximum elongation value of 200 to 750%, preferably 200 to 650%, more preferably 300 to 400%.

The chewing time of the pet food or the pet sandwich of the invention is at least 15 minutes, preferably at least 0 minutes.

The invention will now be illustrated through a number of examples.

EXAMPLES Materials: - Vital wheat gluten (Amygluten 110 and 160), 94% d.s. The Amygluten 160 has a development time of the mass of 10 min, determined in a rotary batch mixer with counter (Brabender Plastograph), while the Amygluten 110 has a development time of the mass of 5 min in the same conditions. These time values correspond to the maximum torque value measured in the plastgraph, while mixing a composition of 100 parts by weight of gluten and 53 parts by weight of glycerol. - Protinax 132 vital wheat gluten. - Food grade glycerol (14% water content) Equipment: The extrusion is carried out with a twin-screw extruder of joint and self-drilling rotation with a drum diameter (D) of 53 mm (Clextral Evolum 53). The extruder drum consists of 10 zones of 212 mm in length, each zone being equipped with an independent temperature control based on resistance heaters and water circulation in a double jacket. The feeding zone is cooled by water circulation. The total length of the screw is 40D. Each screw consists of double elements of right threaded screws with different steps. This allows to develop the viscosity as late as possible. The gluten powder is fed with a twin screw gravimetric feeder and the gluten with a measuring pump.

The temperature of the drum mentioned below was determined at the end of the screw (last drum).

The SME value within the framework of the present invention has been determined according to the following equation: SME = N / Nmax * 1 / D * U * I * 0. 9 where: N = read speed of the screw Nmax = maximum screw speed of the extruder D = dry mix speed (kg / h) U = difference of armature potential in the DC motor (V) I = motor amperage consumption - electric (A) 0.9 = coefficient that takes into account the losses between the electric motor and the gearbox EXAMPLES 1-3 In the following examples, a screw configuration that only contains transport elements was used. Two compositions of wheat gluten (Amygluten 160) were tested. The third composition was the same as Example 2 except that different gluten material was used (Amygluten 110).

Traction measurement: speed of 10 mm / min Penetrometry test with 45 ° cone; penetration depth of 6 mm.

In the case of Example 1, a homogeneous, plastic and deformable material was obtained. This material was molded in a separate step, immediately after extrusion. After storing the molded material for 24 hours at room temperature, a product with rubber elasticity was obtained which could no longer be reformed at room temperature.

In the case of Example 2, the lower plasticizer content resulted in a very elastic, extensible rubber-like material, which could no longer be formed by "cold" techniques such as lamination. However, it did not cause problems to cut it in any desired way, while the hot molding allowed to reform the material. However, the mechanical properties changed during hot molding, providing compositions that were still elastic but harder (higher E-modulus) and less extensible.

In Example 3 the same conditions as in Example 1 were used. Amygluten 160 was replaced by Amygluten 110, which has a shorter time of dough development.

This resulted in a cohesive and very elastic rubber-like material, which showed very high extruded growth (about 200%, calculated as extruded diameter / die diameter * 100). The material could be formed by means of "cold" techniques such as lamination.

This illustrates that different types of vital wheat gluten can be used.

EXAMPLES 4 TO 6 Fabrication of examples in which the elements of the last drum were cooled with glycol water (at -6 ° C). All experiments were performed using Amygluten 160. Traction measurement: speed of 10 mm / min Penetrometry test with 45 ° cone; penetration depth of 6 mm.

In all three homogeneous examples, rubber-like extrudates were obtained.

EXAMPLES 7, 8 AND 9 Chewable snacks for pets Manufacturing examples in which the elements of the last drum are cooled with glycol water (at -6 ° C).

The extrusion parameters, the recipe and the characterizations of the extrudates are presented in Tables 1, 2 and 3.

The shape of the extrudates produced was a cylinder (diameter: 55 mm / length: 150 mm).

TABLE 1 TABLE 2 Example 8 54.2% Amylogluten 160 22.5% glycerol Extruded composition (w / w) 11.9% water 11.4% other dry ingredients TABLE 3 METHOD TO MEASURE THE MASTICATION TIME Principle: Dogs are fed a snack between 1:00 PM and 4:00 PM, i.e., 5 to 6 hours after receiving their main meal. The sandwich is presented to the animal by giving it to the mouth with the hand. The chewing time can be measured, as well as the occupation time. It is compared to a product of the same size and weight, or the target competitor. The time of chewing represents only the duration of biting, chewing, chewing and ingesting the product.

Test procedure: Animals All dogs in the kennel can be used for the sandwich test. A preselection can be made, to reject the dogs that will not participate in the sandwich test. These dogs are separated as follows: - large dogs - medium dogs - small dogs Within a subgroup of dogs, the distribution of body weight, sex and ages should be balanced.

The breed of the dog can be selected depending on the size of the sandwich to be tested. In this case, only large dogs were selected (see below).

In the same breed, dogs can be divided into different balanced subgroups to test the same product every day to be evaluated.

Environment The sandwich test is conducted in kennels indoors. Otherwise, the dogs are housed in pairs inside / outside kennels. The temperature is maintained between 15-21 ° C. Dogs follow the natural nictemeral cycle.

Tap water ad libitum is provided through an automatic system. The usual feeding pattern of the dogs is not disturbed when the sandwiches are tested, which is a dry or moist main meal that is given ad libitum for 30 min between 7:45 AM and 8:15 AM.

Test design When comparing several products, a Latin square design is applied to cancel any effect of the order of presentation of the sandwich, or any effect of the first day's novelty, on the intake of the sandwiches. In this case, there are as many panels participating in the study and days of experimentation, as tested products (Table 4). In a week, a maximum of four products can be tested (4 experimental days). TABLE 4 An example of a Latin square design for testing four products (A vs B vs C vs D) Materials To perform the sandwich test, some materials are needed: For each product that is going to be tested: n sandwiches, where n is the number of dogs to be tested per day; - A chronometer; - A format of results Chewing time For each test, the number of dogs is determined for those who: - have been tested - have rejected the product (they did not take it with their mouth, see below); - They have participated in the test.

The duration of chewing is determined on the dogs that have participated in the test. It adds up all the time that the product is taken between the jaws, biting, gnawing, chewing, as well as swallowing the pieces of the sandwiches.

The chewing time was carried out with 30 large dogs (weight> 25 kg). The following breeds were used to perform the test: Labrador, German Pointer, German Shepherd, Rottweiler, Bernese, Airdale Terrier, Golden Retreiver and Dalmatian.

Claims (32)

1. Method for manufacturing plasticized gluten compositions for pet food applications or pet snacks, the method comprising the steps of: - mixing at least gluten and a plasticizer; - where the mixing equipment is adjusted to a value below 50 ° C and the SME (Specific Mechanical Energy) applied to the mixture is less than 600 kJ / kg, - where the gluten content is between 20 and 85% by weight; - where the plasticizer content is less than 40% by weight.

2. Method according to claim 1, characterized in that the gluten content is between 0 and 85% by weight.

Method according to any of the preceding claims, characterized in that the mixing is carried out with an SME of less than 200 kJ / kg.

Method according to any of the preceding claims, characterized in that the plasticizer is glycerol.

Method according to any of the preceding claims, characterized in that the plasticizer content is between 15 and 40%.

Method according to any of the preceding claims, characterized in that the plasticizer content is below 35%.

Method according to any of the preceding claims, characterized in that the plasticizer content is below 30%.

8. Method according to any of the preceding claims, characterized in that the plasticizer content is below 25%.

9. Method according to any of the preceding claims, characterized in that the plasticizer content is below 20%.

Method according to any of the preceding claims, characterized in that the mixing is carried out with an SME of more than 75 kJ / kg, preferably of more than 150 kJ / kg, most preferably, of 150 kJ / kg.

Method according to any of the preceding claims, characterized in that the temperature of the mixing equipment is adjusted to a value between -10 ° C and 45 ° C.

Method according to any of the preceding claims, characterized in that the temperature of the mixing equipment is adjusted to a value between -10 ° C and 0 ° C.

Method according to any of the preceding claims, characterized in that the mixing is carried out continuously.

14. Pet food obtainable by means of a method according to any of the preceding claims.

15. Pet food or pet food, chewable, obtainable by mixing at least gluten and a plasticizer by applying an SME of less than 250 kJ / kg, where the plasticizer content is below 40% by weight of the Total mixing mass.

16. Chewable dog food sandwich, comprising plasticized gluten which is composed of 55-75 parts by weight of gluten and 35-20 parts by weight of plasticizer, the sandwich having a maximum elongation value of 200 to 750% and a chewing time, when chewed by dogs, of at least 15 minutes.

17. A chewable dog food sandwich according to claim 16, characterized in that the plasticized gluten is composed of 65-75 parts by weight of gluten and 35-25 parts by weight of a plasticizer, the sandwich having an elongation value maximum of 200 to 650% and a chewing time, when chewed by dogs, of at least 20 minutes.

18. A chewable dog food snack according to any of claims 16 or 17, characterized in that the plasticizer is glycerol.

19. Chewable pet food sandwich comprising plasticized gluten, which has a maximum breaking force in the range of 200 to 850 N.

20. Pet food snack according to claim 19, characterized in that it has a maximum breaking force on the scale of 200 to 600 N.

21. Pet food snack according to claim 19, characterized in that it has a maximum breaking force in the range of 200 to 400 N.

22. Pet food snack according to claim 19, characterized in that it has a maximum breaking force in the range of 200 to 350 N

23. Pet food snack according to any of claims 19 to 22, characterized in that the gluten is plasticized with a glycerol-containing plasticizer.

24. Pet food snack according to any of claims 19 to 23, characterized in that the plasticized gluten is composed of 50-75 parts by weight of vital wheat gluten and 50-25 parts by weight of a plasticizer.

25. Pet food snack according to any of claims 19 to 24, characterized in that the plasticized gluten is composed of 55-75 parts by weight of vital wheat gluten and of 35-20 parts by weight of a plasticizer.

26. Pet food or pet snacks according to any of claims 19 to 24, characterized in that the plasticized gluten is composed of 60-70 parts by weight of vital wheat gluten and 40-30 parts by weight of a plasticizer.

27. Pet food or pet snacks according to any of claims 19 to 26, characterized in that it has a maximum elongation value of 200 to 750%.

28. Pet food or pet snacks according to any of claims 19 to 27, characterized in that it has a maximum elongation value of 200 to 650%.

29. Pet food or pet snacks according to any of claims 19 to 28, characterized in that it has a maximum elongation value of 300 to 400%.

30. Pet food or pet snacks according to any of claims 19 to 29, characterized in that the pet food. It is a sandwich of chewable food for dogs that have a chewing time of at least 15 minutes.

31. Pet food or pet snacks according to claim 30, characterized in that the pet food is a chewable dog food sandwich having a chewing time of at least 20 minutes.

32. Use of plasticized gluten to produce a chewable pet food sandwich, where the plasticized gluten is manufactured according to any of claims 1 to 13.