BLOOD CHUNKS

Abstract: The invention provides a method of manufacturing a blood chunk. The method comprises heating a blood fraction, adding hydrogen peroxide, and compressing the resulting reaction product to form a chunk having a laminar structure. An edible chunk comprising a major proportion of blood protein and having a fibrous, laminar internal structure is also described.

Description: BLOOD CHUNKS The present invention relates to the preparation of a novel edible cnunk comprising blood, and to the chunk itself. Blood and blood fractions are used m the manufacture of pet foods as a nutrient. In particular, tne hemoglobin fraction of whole blood is employed; by the nanoglobm fraction is meant the residue from whole blooα once the plasma, or most of tne plasma, nas been removed. The haemoglobin fraction consists of reα ana wnite blood cells with a residue of plasma. The hemoglobin fraction typically contains from about 14% to 40% protein and about 35% to 45% red blood cells. The remainder is mainly water together with other blood components. Conventionally, whole blood is heated by scraped surface heating or steam infusion to 75°C and treated with hydrogen peroxide to decolour it. The decoloured blood is dewatered to give a powder. In alternative tecnniques, whole blood is coagulateα witn for example a solution containing calcium ions and the resulting coagulate cut into chunks. Sucn chunks are homogeneous m texture, resembling liver. It has now been found that if a blood fraction, defined herein as comprising from about 14% to about 40% protein and about 35% to 45% red blood cells, is heated and treated with hydrogen peroxide a solid foam results. The foam reaction product can be cut into chunks and incorporated into, for example, pet food. If the foam reaction product is compressed, a textured solid mass is produced. The compressed solid mass has a laminar structure similar to that of cooked meat. The blood fraction may be formed in any way. The blood fraction may be the haemoglobin fraction of blood. Alternatively, the blood fraction may be formed by removing water from whole blood to concentrate it so that it comprises from about 14% to about 40% protein and about 35% to 45% red blood cells. The blood fraction may be reconstituted from purified protein and red blood cells. According to the invention there is provided a method of forming a blood chunk comprising heating a blood fraction (as defined above), treating the heated blood fraction with hydrogen peroxide and compressing the resulting reaction product to form a chunk having a laminar structure. Preferably the blood fraction is a haemoglobin fraction (as defined above) . Preferably the hydrogen peroxide is added to the blood fraction at at least 0.5% by weight. There does not appear to be a significant upper limit to the concentration of hydrogen peroxide in the reaction mixture which is effective to cause the desired reaction to take place; concentrations of up to 3% (by weight) have been found satisfactory. Preferably, compression is carried out at a temperature greater than 60°C. Preferably the blood fraction is heated to between 60 C C and 80°C before addition of the hydrogen peroxide. Preferably the blood fraction comprises at least about 10%, more preferably at least about 15%, by weight protein. At lower protein concentrations, the reaction product does not absorb all the water present in the reaction mixture. Such products are useful and their manufacture falls within the scope of the present invention; however, it will usually be necessary to remove the proteinaceous material from the unabsorbed water before it s used. Additives may be included m the blood fraction to modify the nutritional content and flavour of the chunks. It is preferred that the pH of the blood fraction is no less than 4, and that it is no greater than 9. Compression of the reaction product of the blood fraction and hydrogen peroxide can be carried out on the reaction product as it is formed, or the reaction product can be stored and then subjected to heating, for example by microwave radiation, prior to compressing. Alternatively, the reaction product may be steamed to give a product having a jelly-like texture. The steaming can be carried out with meat juices or other flavoured aqueous media to impart particular flavours to the product. The product can be dried, preferably at about 60°C, to produce hard, crunchy chunks, which are useful as a dry pet food. The reaction product of the blood fraction and hydrogen peroxide can be compressed under its own weight. The reaction product may be compressed as a result of restriction of any expansion of the reaction product caused by evolution of gas as the blood fraction and hydrogen peroxide react. The pressure at which the reaction product of the blood fraction and hydrogen peroxide is compressed to achieve the laminar internal structure is not critical; a pressure of up to about 400 kPa is preferred. Also according to the invention there is provided an edible chunk comprising a major amount of blood protein and having a fibrous, laminar internal structure. The invention will be further described, by way of example, with reference to the drawings in which; Figure 1 shows schematically a method according to a first embodiment of the invention; Figure 2 shows schematically a method according to a second embodiment of the invention; and Figure 3 shows schematically a method according to a third embodiment of the invention. The methods according to the invention shown in the drawings include the following common features. The hemoglobin fraction of blood is pumped from a tank 10 by a peristaltic pump 12 to a steam infuser 14 where the hemoglobin is heated to about 75°C. The heated hemoglobin passes from the steam infuser 14 to a high shear mixer reactor 16, such as a Dispax reactor. In the Dispax reactor, the haemoglobin is reacted with hydrogen peroxide pumped from a hydrogen peroxide tank 18 by a hydrogen peroxide pump 20. In the reactor 16, the hemoglobin and the hydrogen peroxide are mixed efficiently. Preferably, the reactor is a high shear, low volume mixer to ensure adequate mixing of the two components. In the first embodiment of the invention, shown in Figure 1, the foam reaction product 22 is deposited in a tray 24. The reaction product 22 can be allowed to be compressed by its own weight, in which case the solid mass produced is elastic and can be cut up to provide elastic chunks. Alternatively, pressure can be applied to the reaction product 22 in the tray by application of a pressure plate 26. On release of the pressure plate a solid product 28 having a fibrous, laminar internal structure is produced, which can then be cut into chunks 30 as at 32. In the second embodiment of the invention, shown in Figure 2, the reaction product 22 from the reactor 16 is passed to a piston pump 40 in which the reaction product is compressed. As the reaction product 22 leaves the piston pump 40, it is diced as at 42 to produce chunks 44 having a fibrous, laminar internal structure. In the third embodiment of the invention, shown in Figure 3, the reaction product 22 leaves the reactor 16 through a disperser 50, from where it passes into a mouth formed by the widely separated ends of two converging continuous belts 52, 44. The reaction product is compressed between the two continuous belts, and the resulting solid sheet 56 is cut into chunks 58 as it leaves the continuous belts 52, 54, as at 60. Again, the chunks produced have a fibrous, laminar internal structure. The chunks have a fibrous, laminar internal structure, similar to that of meat chunks, so that the chunks can be readily used in canned food stuffs such as pet foods to provide a protein source which is analogous m appearance and texture to meat.

Claims: CLAIMS 1. A method of manufacturing a blood chunk comprising: heating a blood fraction (as herein defined) ; adding hydrogen peroxide; and compressing the resulting reaction product to form a chunk having a laminar structure. 2. A method according to claim 1 in which the blood fraction is a hemoglobin fraction (as herein defined) . 3. A method according to claim 1 or 2 in which the compression is carried out at a temperature greater than 60°C. 4. A method according to any preceding claim in which the compressed product is dried. 5. A method according to any preceding claim further comprising steaming the reaction product of the blood fraction and the hydrogen peroxide. 6. A method according to any preceding claim in which the hydrogen peroxide is added to the blood fraction at at least 0.5% (by weight) . 7. A method according to any preceding claim in which the blood fraction is heated to between 60°C and 80°C before addition of the hydrogen peroxide. 8. A method according to any preceding claim in which the blood fraction comprises at least 10%, preferably at least 15%, protein by weight. 9. An edible chunk comprising a major proportion of blood protein and having a fibrous, laminar internal structure. 10. A method substantially as described. 11. A chunk substantially as described.

Inventors: FISHER TIM, SPEIRS CHARLES, FISHER, TIM, SPEIRS, CHARLES
Applicants: FISHER TIM, MARS UK LTD, SPEIRS CHARLES, FISHER, TIM, MARS UK LIMITED, SPEIRS, CHARLES
Application year: 1999
Main classification: A23J3
IPC codes: A23J3, A23K1