TECHNICAL FIELD

The present invention relates to a composition comprising elastin, said composition having an improved oil and water binding capacity and improved emulsification properties. The composition of the present invention is specifically suitable for use in food and pet food applications as protein supplement or as replacement of specific texturizing ingredients.

BACKGROUND OF THE INVENTION

Functional ingredients for use in food and pet food are widely used for providing the right properties to said food and pet food, such as texture, cooking stability, cutting properties (eg sliceability) etc. Important parameters to provide texture are water binding capacity, oil binding capacity, emulsification properties and so on. Different ingredients are used nowadays, each with their own advantages and drawbacks. For example blood plasma is widely used as an ingredient in food applications such as sausages, cooking sausages and the like. Several attempts have been made in the art to find replacer ingredients for blood plasma. Other existing texturizers contain still high amounts of collagen in order to provide the desired functional properties to food and pet food applications.

Currently, animal skin residue and in particular pig skin residue, which is the remaining of the animal skin after collagen extraction for gelatin production, is a by product of the gelatin production process. This product usually sold as an ingredient for mere protein enrichment. The current invention has found ways to improve and upgrade this product.

The present invention aims at providing a composition having improved functional properties and being suitable to provide e.g. right texture to food or pet food applications on its own or in combination with other texturizing ingredients such as blood plasma.

SUMMARY OF THE INVENTION

The present invention is defined in the appended claims. In a first aspect, the present invention relates to a composition comprising elastin, characterized in that it has: a. A protein content of at least 60wt% b. 90V% of the composition has a particle size of less than about 310pm.

In a further aspect, the present invention relates to a process for producing a composition according to the present invention, said process comprising the steps of: a. Providing an aqueous slurry of animal skin residue material, and b. Drying the animal skin residue, and c. Grinding the dried animal skin residue, and d. Optionally sieving and e. Collecting the composition.

In a further aspect, the present invention relates to a composition comprising elastin, characterized in that: a. It has a protein content of at least 60wt% b. 90V% of the composition has a particle size of less than about 310pm c. The composition is prepared by drying and grinding an animal skin residue during 15minutes or less, while the animal skin residue remains at a temperature of 100°C or less.

In a further aspect, the present invention relates to a food, pet food or pharmaceutical application comprising the composition of the present invention and further food, pet food or pharmaceutical ingredients.

In a further aspect, the present invention relates to the use of the composition of the present invention as blood plasma replacer ingredient in food applications or pet food applications.

DETAILED DESCRIPTION

In a first aspect, the present invention relates to a composition comprising elastin, characterized in that: a. A protein content of at least 60wt% b. 90V% of the composition has a particle size of less than about 310pm. Elastin is an insoluble protein found in the skin of animals. Preferably the elastin is obtained from the skin of mammals, more preferably from pigs. The composition of the present invention may also be called animal skin residue composition, preferably pigskin residue composition, as it results from processing animal skin, preferably pigskin, preferably after at least a partial extraction of the collagen from the skin, said collagen typically being used to produce gelatin and/or collagen hydrolysate (i.e. further hydrolysis of gelatin).

The composition of the present invention is further characterized in that it comprises about 3,5wt% or less of the amino acid hydroxyproline. Preferably the composition of the present invention comprises from about 0,2wt% to about 3,5wt%, more preferably from about 0,2 to about 2wt%, even more preferably from about 0,2 to about l,5wt%, yet even more preferably from about 0,2 to about l,5wt%, yet even more preferably from about 0,2 to about lwt%, yet even more preferably from about 0,5 to about lwt% of hydroxyproline.

Preferably further the composition of the present invention has a pH of from 4 to 5,5.

The composition of the present invention preferably has a protein content of at least 65wt%, more preferably at least 70wt%, even more preferably at least 75wt%, yet even more preferably at least 80wt%, yet even more preferably at least 85wt%, yet even more preferably at least 90wt%, yet even more preferably at least 95wt%, such as from 95wt% to 99wt%.

The composition of the present invention is characterized in that 90V% (Volume %) has a particle size of less than about 310pm, further preferably in that 75 V% has a particle size of less than about 210pm, further preferably in that 50V% has a particles size of less than about 140pm, further more preferably in that 25V% has a particle size of less than about 80pm, further even more preferably in that 10V% has a particle size of less than about 50pm.

The particle size is measured with a Beckman Coulter laser diffraction particles size analyzer. The measurement is made on dry product as is typically done in the art.

Preferably further, the composition of the present invention is characterized by its wet particle size. Wet particle size is measured according to the method described below. Preferably the wet particle size distribution of the composition of the present invention is as follows: 90V% of the composition has a particle size of less than about 450pm, more preferably 75 V% has a particle size of less than about 280pm, even more preferably 50V% has a particle size of less than about 165pm, even more preferably 25V% has a particle size of less than about 95pm, yet even more preferably 10V% has a particle size of less than about 55pm.

The composition of the present invention has a moisture content of from 2 to 15wt%, preferably from 3 to 14wt%, more preferably from 3 to 12wt%, even more preferably from 3 to 10wt%, yet even more preferably from 3 to 8wt%, yet even more preferably from 3 to 6wt%, yet even more preferably from 3 to 5wt%.

Further preferably, the composition of the present invention has an ash content of about 2wt% or less.

Further preferably, the composition of the present invention has a collagen content of 12wt% or less,10wt% or less, preferably from 2 to 8wt%, more preferably from 2,5 to 8wt%, even more preferably from 3 to 8wt%, even more preferably from 3,5 to 8wt%, yet even more preferably from 4 to 8wt%, yet even more preferably from 5 to 8wt% and yet even more preferably from 6 to 8wt%. This further improves the functional properties of the present composition. It has been found that despite the low amount of collagen in the composition of the present invention, compared to existing texturizing compositions, the composition of the present invention still has advantageous functional properties such as described herein.

The water binding capacity of the present composition is advantageous in that the product can easily be incorporated in several food and pet food applications. Food applications are for example meat preparations such as sausages, more particularly cooking sausages, liver pates, ham for example. Pet food applications are wet pet food, extruded wet pet food products. Water binding capacity means the amount of water that the product can hold, even after a heating step and translates into amongst other things following parameters in food and pet food applications: less water loss after after a heat treatment (eg cooking step), less/reduced syneresis during conservation.

The composition of the present invention has a water binding capacity measured at 20°C, according to the method described below, of from 200 to 500%, preferably of from 210 to 460%, more preferably of 220 to 460%, preferably of from 230 to 460%, more preferably of 240 to 460%, even more preferably of 250 to 460%, yet even more preferably of 260 to 460%, yet even more preferably of 270 to 460%, yet even more preferably of 280 to 460%, yet even more preferably of 290 to 460%, yet even more preferably of 300 to 460%, yet even more preferably of 310 to 460%, yet even more preferably of 320 to 460%, yet even more preferably of 330 to 460%, yet even more preferably of 340 to 460%, yet even more preferably of 350 to 460%, yet even more preferably of 360 to 460%, yet even more preferably of 370 to 460%, yet even more preferably of 380 to 460%, yet even more preferably of 390 to 460%, yet even more preferably of 400 to 460%, yet even more preferably of 410 to 460%, yet even more preferably of 420 to 460%, yet even more preferably of 430 to 460%, yet even more preferably of 440 to 460%, yet even more preferably of 450 to 460%.

Further preferably, the composition of the present invention also has a water binding capacity measured at 76°C, according to the method described below, of from 200 to 450%, preferably of from 210 to 440%, more preferably of 220 to 440%, even more preferably of 230 to 440%, yet even more preferably of 240 to 440%, yet even more preferably of 250 to 440%, yet even more preferably of 260 to 440%, yet even more preferably of 270 to 440%, yet even more preferably of 280 to 440%, yet even more preferably of 290 to 440%, yet even more preferably of 300 to 440%, yet even more preferably of 310 to 440%, yet even more preferably of 320 to 440%, yet even more preferably of 330 to 440%, yet even more preferably of 340 to 440%, yet even more preferably of 350 to 440%, yet even more preferably of 360 to 440%, yet even more preferably of 370 to 440%, yet even more preferably of 380 to 440%, yet even more preferably of 390 to 440%, yet even more preferably of 400 to 440%, yet even more preferably of 410 to 440%, yet even more preferably of 420 to 440%, yet even more preferably of 430 to 440%.

Further, preferably the composition of the present invention has an oil binding capacity measured at 20°C, according to the method described below, of 110 to 350%, more preferably of 115 to 340%, even more preferably from 120 to 330%, even more preferably of 130 to 330%, even more preferably of 140 to 330%, even more preferably of 150 to 330%, even more preferably of 160 to 330%, even more preferably of 160 to 330%, even more preferably of 170 to 330%, even more preferably of 180 to 330%, even more preferably of 190 to 330%, even more preferably of 200 to 330%, even more preferably of 210 to 330%, even more preferably of 220 to 330%, even more preferably of 230 to 330%, even more preferably of 240 to 330%, even more preferably of 250 to 330%, even more preferably of 260 to 330%, even more preferably of 270 to 320%, even more preferably of 280 to 320%, even more preferably of 290 to 320%, even more preferably of 300 to 320%. Further, preferably the composition of the present invention has an oil binding capacity measured at 76°C, according to the method described below, of 105 to 320%, more preferably of 110 to 320%, even more preferably from 115 to 320%, even more preferably of 120 to 310%, even more preferably of 130 to 310%, even more preferably of 140 to 310%, even more preferably from 150 to 310%, even more preferably of 160 to 310%, even more preferably of 170 to 310%, even more preferably of 180 to 310%, even more preferably of 190 to 310%, even more preferably of 200 to 310%, even more preferably of 210 to 310%, even more preferably of 220 to 310%, even more preferably of 230 to 310%, even more preferably of 240 to 310%, even more preferably of 250 to 310%, even more preferably of 260 to 310%, even more preferably of 270 to 310%, even more preferably of 280 to 310%, even more preferably of 290 to 310%, even more preferably of 300 to 310%.

Further, preferably the composition of the present invention is characterized in that it has an emulsification capacity of from 60 to 95%, more preferably from 65 to about 99%, more preferably from 70 to 98%, even more preferably from 75 to 97%, yet even more preferably from 77 to 96%, yet even more preferably from 78 to 95%, yet even more preferably from 80 to 94%, yet even more preferably from 82 to 93%, yet even more preferably from 85 to 93%.

In a further aspect, the present invention relates to a process to produce the composition of the present invention, said process comprises the steps of: a. Providing an aqueous slurry of animal skin residue, and b. Drying the animal skin residue, and c. Grinding the dried animal skin residue, and d. Optionally sieving and e. Collecting the composition.

As mentioned above, the animal skin residue, preferably pigskin residue, is the residual skin of the animals that is obtained after extraction of collagen has been done, typically in a gelatin producing plant. The animal skin of step a. of the process of the present invention may be obtained after one or more collagen extraction cycles. For example, the animal skin may be obtained after two, three or four collagen extraction cycles. This will influence the collagen content of the animal skin residue and therefore the collagen content of the composition obtainable by the process of the present invention. Preferably, the aqueous slurry of animal skin residue is obtained after separating fat and part of the water from the animal skins after collagen extraction. Separating fat and part of the water may be done using a two phase decanter, preferably using a three phase decanter.

The aqueous slurry of step a. comprises from 50 to 80wt% of water, preferably from 60 to 70wt% of water. Before the decanter, a pasteurization step may be done.

Preferably before entering the dryer, the aqueous slurry of animal skin residue is passed in a backmixer where some dry product can be added. The amount of dry product to be added depends amongst other things on the moisture content of the animal skin residue which can be adapted to improve the performance of the drying equipment.

The process of the present invention is further characterized in that the drying is performed during 15 minutes or less, preferably during 10 minutes or less, more preferably during 8 minutes or less, even more preferably during 5 minutes or less, even more preferably during 1 minute or less, yet even more preferably during 30 seconds or less, yet even more preferably during 25 seconds or less, yet even more preferably during 20 seconds or less, yet even more preferably during 15 seconds or less, yet even more preferably during 10 seconds or less, yet even more preferably during 5 seconds or less, such as from 1 to 5 seconds.

Drying is done until the product reaches a dry substance of from 2 to 15wt%, preferably from 3 to 14wt%, more preferably from 3 to 12wt%, even more preferably from 3 to 10wt%, yet even more preferably from 3 to 8wt%, yet even more preferably from 3 to 6wt%, yet even more preferably from 3 to 5wt%.

Drying is performed with a stream of heated gas (generally air, that may be low in oxygen), heated either by direct or indirect heating, such as for example by using an indirect gas burner. Although the drying gas can reach temperatures of about 200°C, preferably about 190°C, more preferably about 180°C (dryer inlet gas temperature), the product does not reach such high temperatures. Preferably the drying is done such that the average dryer outlet gas temperature is about 130°C or less, more preferably about 125°C or less, even more preferably 120°C or less, even more preferably 115°C or less, yet even more preferably 110°C of less, yet even more preferably 100°C or less. Preferably the temperature of the product remains at a temperature of 100°C or less, more preferably 95°C or less, even more preferably 90°C or less, yet even more preferably 85°C or less, yet even more preferably 80°C or less, yet even more preferably 70°C or less, for example from 80°C to 60°C or from 70°C to 60°C.

Preferably, the drying is performed with a method allowing low heat damage, such that the composition retains advantageous functional properties such as water binding and oil binding capacity for example. Preferably thus drying is done by convection in a flow of heated gas and drying may be done by fluidized bed, ring drying, air turbulence mill drying and the like.

Drying may also be done by freeze drying.

In a preferred embodiment, the drying step is performed at atmospheric pressure while forming small particles, such that drying is very efficient. Preferably thus the drying and the grinding steps are done substantially simultaneously. Such drying may be done in an air turbulence mill. Several types of air turbulence miss exist. They are generally referred to as turbulent air grinding or vortex air mills. Some of there are also named 'spin driers and grinders', and others also 'flash dryer and grinders'. Spin dryers and grinders and flash dryers and grinders basically dry and mill wet product in a very short period of time The rotor generally is positioned vertically relative to the outlet. It is preferred to use vertically positioned rotors, as they appear to use less energy.

Air turbulence mills, such as those known in the art from Atritor (Cell Mill), Hosokawa (Drymeister), Larsson (Whirl flash), Jackering (Ultra Rotor), Rotormill, Gorgens Mahltechnik (TurboRotor) or SPX may be used for drying and grinding in the present invention.

The air turbulence mill may comprise a classifier, which causes a separation of larger and smaller particles. The use of a classifier allows the larger particles to be returned to the grinder, while smaller particles are left through for further processing. It is noted that if needed, a further grinding step or sieving step may still be performed after drying in an air turbulence mill.

The present invention also relates to a composition comprising elastin, characterized in that: a. It has a protein content of at least 60wt% b. 90V% of the composition has a particle size of less than about 310pm c. The composition is prepared by drying and grinding an animal skin residue during 30 minutes or less, preferably during 15minutes or less, preferably during 10 minutes or less, more preferably during 8 minutes or less, even more preferably during 5 minutes or less, even more preferably during 1 minute or less, yet even more preferably during 30 seconds or less, yet even more preferably during 25 seconds or less, yet even more preferably during 20 seconds or less, yet even more preferably during 15 seconds or less, yet even more preferably during 10 seconds or less, yet even more preferably during 5 seconds or less, such as from 1 to 5 seconds., while the animal skin residue remains at a temperature of 100°C or less, more preferably 95°C or less, even more preferably 90°C or less, yet even more preferably 85°C or less, yet even more preferably 80°C or less, yet even more preferably 70°C or less, for example from 80°C to 60°C or from 70°C to 60°C, further preferably wherein the drying and grinding is done simultaneously, such as in an air turbulence mill.

Preferably thus the present invention relates to a composition comprising elastin, obtainable by the process of the present invention.

As mentioned already, the composition of the present invention shows an improved heat stability meaning that when used in food or pet food applications where a heating step is done during the production process, such as a sterilization step for example, the composition of the present invention does not lose or loses only to a certain extent its functional properties, in particular water binding capacity, oils binding capacity, emulsification capacity; unlike many existing texturizers. Therefore, the composition of the present invention is suitable for use in such applications.

In a further aspect, the present invention relates to a food or pet food application comprising the composition of the present invention and further food and pet food ingredients. Preferably food applications are meat preparations, preferably sausages, in particular cooking sausages, liver pates or hams for example. Preferably pet food applications are wet pet food, extruded wet pet food products. As mentioned above the use of the present composition in food and pet food applications allows to improve the quality of food and pet food applications by influencing parameters such as water holding capacity (or cooking loss, how better the water holding capacity how less cooking loss) and syneresis. Further the texture of food and pet food applications may be improved by incorporation of the composition of the present invention, e.g. sliceability, hardness, consistency, elasticity and so on. Typically, the food or pet food application may comprise from about 0,5 to 10wt%, preferably from 1 to 5wt%, preferably 1 to 4wt%, more preferably 2 to 4wt% of the composition of the present invention. In a further aspect, the present invention relates to the use of the present composition to fully or partially replace blood plasma in food applications or pet food applications, preferably in heat processed food and pet food applications. Preferably food applications are meat preparations, preferably sausages, in particular cooking sausages, liver pates or hams for example. Preferably pet food applications are wet pet food, extruded wet pet food products.

Methods of measurement

Dry particle size

5g of product is introduced in the Beckman Coulter particle size analyser and particle size is measured at 20°C. Wet particle size

5g of product is put in 100ml water at 20°C and mixed for 30minutes with a magnetic stirrer. This aqueous composition is then introduced in the Beckman Coulter particle size analyser.

Water binding capacity Preparation of buffer solution:

1) 4.0 g NaH2P04 and 70.0 g NaCI is dissolved in 1500 g demi-water

2) the solution is corrected to pH 6.0 using 89.0 g 0.1 N NaOH

3) the solution is diluted to 2000 g using demi-water.

Protocol 20 °C

1) 2 g of protein is weighed in a pre-weighed centrifuge tube of 50 mL

2) 8 g (or more in case of a high water binding capacity) of buffer is added dropwise to the protein at room temperature

3) The centrifuge tube is shaken during 1 minute on a lab shaker

4) Centrifugation for 10 min at 2000 g (= 3150 rpm on Allegra 6R centrifuge)

5) Decantation of supernatant (buffer)

6) Weighing of the pellet.

Protocol 76 °C

Similar to the protocol at 20 °C, but:

1) the centrifuge tube is pre-heated to 76 °C

2) the buffer is pre-heated to 80 °C

3) 5 g of protein is used 4) 20 g of buffer is added

5) after shaking, the protein-buffer mixture is heated at 76 °C for 20 min.

Water binding capacity WBC (%) is calculated as follows:

[(weight pellet - weight dry protein) / weight dry protein] x 100

Oil binding capacity Protocol 20 °C

1. 5 g of protein is weighed in a pre-weighed centrifuge tube of 50 mL

2. 10 g (or more in case of a high oil binding capacity) of sunflower oil (Vandemoortele) is added dropwise to the protein at room temperature

3. The centrifuge tube is shaken during 1 minute on a lab shaker - visual check that all protein powder is in contact with oil (no dry particles)

4. Centrifugation for 10 min at 2000 g (= 3150 rpm on Allegra 6R centrifuge)

5. Decantation of supernatant (oil)

6. Weighing of the pellet.

Protocol 76 °C is similar to the protocol at 20 °C, but:

1. the centrifuge tube is pre-heated to 76 °C

2. the oil is pre-heated to 80 °C

3. 15g of oil is added

4. after shaking, the protein-oil mixture is heated at 76 °C for 10-15 min.

Oil binding capacity OBC (%) is calculated as follows:

[(weight pellet - weight dry protein) / weight dry protein] x 100

Emulsification capacity

Preparation of protein solutions and SDS solution:

0.15 % protein solutions: 1. 4.0 g NaH2P04 and 70.0 g NaCI is dissolved in 1500 g demi-water

2. the solution is corrected to pH 6.0 using 89.0 g 0.1 N NaOH

3. the solution is diluted to 2000 g using demi-water

4. preparation of a 0.15% protein solution/suspension in the buffer solution of step 3. 0.1 % SDS solution:

1.00 g SDS is dissolved in 1000 g demi-water.

Protocol: 1. The solution/suspension of 0.15 % protein in the phosphate buffer (pH 6) containing 3.5 % NaCI is stirred for 1 h at room temperature

2. 8 volumes of the protein solution/suspension of step 1. (100 ml.) is mixed with 2 volumes sunflower oil (Vandemoortele) (25 ml.)

3. An emulsion is prepared by homogenization of the mix of step 2. using a Ultra-Turrax homogenizer: 1 min. at 12000 rpm (recipient: 250 ml. Schott bottles)

4. 5-10 seconds after homogenization, 250 pL of the bottom of the emulsion is added to 25 mL of the 0.1 % SDS solution (recipient: 100 mL Schott bottles)

5. The solution is shaked/mixed for 0.5 min, Turrax-mixing (4000 rpm); measurement of the absorbance 3 min. after mixing

6. Measurement of the absorbance at 500 nm.

7. Steps 4., 5. and 6. are repeated 10 min after homogenization. The present invention will be illustrated in the following non-limiting examples. Example 1

Pig skin received from slaughterhouses was used to produce gelatin (acid process), 3 gelatin extraction broth were produced. The pig skin residue remaining after the 3 ^rd extraction broth was removed, was further processed. The pig skin residue had a moisture content of 48.5% ("wet product") and was dried to a target moisture of 5%.

Drying was done as follows: an air turbulence mill was operated such that the average outlet air temperature was 124°C. An average inlet air temperature of 192°C was used. The mill mean load was controlled to remain at about 67 Amps. The feed is back mixed at a ration 10 wet product : 1,5 dry product (having a moisture content of 5%). Drying time was from 3 to 5 seconds.

Example 2: Production of cooking sausages

The composition of example 1 was used to produce cooking sausages and compared to a reference sausages not comprising the composition of example 1.

275g of meat trimmings, 175g of mechanically deboned pork meat, 200g of ice, l,8g nitrite curing salt were blended together and grinded. After 2 minutes of grinding the composition of example 1 was added (lOg) (note for the reference sausage, no product is added at this point). Grinding was done until a homogeneous batter was obtained, temperature was 5°C. Further, 200g of pork back fat, 200g of ice and spices were added (0,5g sugar; 0,2g white pepper; 0,05 g mace; 0,05 cardamom; 0,05g ascorbate; 0,4g glutamate) and further grinded to obtain a homogeneous batter at a temperature of 14°C. The batter was used to fill sausage casings and the casings were cooked (180 minutes at 75°C). After cooking, the sausages were allowed to cool down until room temperature.

The product appearance is shown in Figures 1 and 2. Fig. 1 is a reference picture. Fig. 2 is a picture of sausage containing composition according to example 1.

The water binding capacity of the sausages is improved by adding the product according to example 1: cooking loss (in weight) is measured for the sausages. The reference sausage shows a cooking loss of more than 8% whilst the sausage with the product of example 1 shows a cooking loss of about 6% only. Thus a reduction of the cooking loss is obtained by the use of the composition of example 1, according to the present invention.