This invention relates to the process for the preparation of the gelatine and the gelatine hydrolyzate from animal bones .

The gelatine and its hydrolyzate are the animal protein which do not occur in the nature but they are produced by the chemical-thermic methods from the collagen. The raw material for the production of the gelatine and the gelatine hydrolyzate is the collagen which is present in the skin, bones and other kinds of the connective tissue. The collagen has a very complicated and outspread protein structure which undergoes partial reduction during the process of the gelatine production, which consequently leads to the changes of its characteristic physical and chemical properties.

The production of the gelatine from animal bones is a very complicated process. The first stage of this process is the appropriate preparation of the bone raw material. In this stage, the bones which are the waste product from the

slaughter of the animals, after the cutting off the meat and the preliminary classification, are crumbled to the bone shot and the defatting is carried out with the hot water or the steam. The dried and defatted bone shot is subjected to the process of demineralization - maceration by traeting it for several to a dozen or so days with the hydrochloric acid diluted to a few percents. The bone raw material cleaned in such a way and called the ossein is used for the production of the gelatine. The by-product precipitated from the acidic bone extract and containing calcium salt is used among others as the component of the fodder feeding stuffes .

The ossein prepared by the acidic method is then subjected to the multi-stage extraction with the hot water and increasing temperature of the process in the subsequent extraction operations. First fractions obtained at the lowest temperature give gels of the highest quality. The material which remains after the first extraction is subjected to the next extraction with the fresh water of a higher temperature. This process is repeated until all the remaining gelatine is transfered to the solution. The gelatine solution obtained after the extraction is next cleaned off the traces of the fat and fibrils derived from the raw material with the use of different known methods, e.g. highly efficient centrifuges and filters. The subsequent stages of the process consist of concentrating, cooling, drying, milling, mixing of the gelatine and preparation for ready use.

The gelatine hydrolyzates are usually produced from the cattle and swine skin. As a result of the longterm maceration, the alkaline molecules of the collagen are decomposed by the proteolytic enzymes to the polypeptides

mixture of a different chain length. The obtained liquid hydrolyzate is then sterilized, concentrated and dried.

Many technological problems are connected with the first stage of the preparation of the raw material for the production of the gelatine in which the bone shot is produced and especially with the stage of defatting the bone raw material. In the defatting process of the bone raw material, prior to the maceration, it is necessary to introduce to the raw material a big quantity of water of a very high temperature and next to drain this water along with the washed out fat. In the defatting process of the raw material, there is removed about 70% of the fat delivered together with the bones in the form of the water-fat emulsion constituting the post-operation residue which creates difficulties in the subsequent processing and produces a big quantity of the liquid wastes . Due to the fact that a large volume of the water is introduced to the raw material, the volume of the liquid wastes formed in this stage is also very big and results in large costs connected with the environment protection against the negative effects. In an overall process, it is also important that the defatting process is carried out in a high temperature which involves a high consumption of the electric and thermal energy required to heat the reactor content and maintain it in a high temperature. The electric and thermal energy is also consumed in the process of drying the product in ^' a very high temperature and the subsequent classification of the bone shot.

The method of the gelatine production from different kinds of the raw material containing the collagen

is known from the international patent application Nr WO9421739. According to the method of this application, the raw material is milled into the particles of the size not exceeding 1 mm and the milled raw material is mixed with water in order to obtain the suspension. The acid is added to the suspension to set pH on the level from 2 to 5 and the suspension is heated to the temperature of 60-1300 ⁰ C at the time from 1 second to 1 hour. In the next stage, the base is added to the suspension in order to rise pH value and the suspension is separated onto the liquid phase containing the gelatine and the solid phase, and then the gelatine is recovered from the liquid phase via filtration and cleaning. In the method of the invention, the preliminary stage may be the defatting of the raw material to the content of the fat on the level of about 3%. It is indicated that this stage is not necessary but it should be taken into account that the method of this application is used for different kinds of the raw material and also for the raw material of a small content of the fat (e.g. oxen skin), and in such a case the defatting may be indeed useless. The analysis of the description and especially of the examples enables the statement that in the case of the use of animal bones as the raw material containing the collagen, the preliminary stage of the defatting is carried out with the technology and the suitable equipment of Alfa Laval Centribone.

According to the method of the application Nr WO9421739, the maceration stage is carried out in a high temperature. Although it is possible to shorten the time of this gelatine production process, in a high temperature the reaction rate significantly rises and by the same rises the

decomposition rate of the organic material. In such circumstances, it is very difficult to set the time of the maceration necessary to obtain the gelatine of the assumed quality in the later part of the process. Moreover, the necessity of milling the raw material to very small particles and adding a large quantity of water to them as well as carrying out the maceration in a high temperature is connected with a high energy consumption. In the case of the use of animal bones as the raw material, the process of the application Nr WO9421739 undoubtedly comprises the preliminary defatting stage. It results from the fact that both in the schematic presentation of the process stages and in the invention description there is no information about the removal of the bone fat introduced in any other stage than the preliminary one and the fat must certainly be removed from the reaction environment.

The subject of the invention is to provide such a process for the preparation of the gelatine and its hydrolyzate which eliminates the problems connected with the preliminary defatting of the raw material in the form of the crumbled bones and especially the process which reduces the volume of the liquid wastes harmful for the environment and also lowers the level of the electric and thermal energy consumption.

The process of the invention for the preparation of the gelatine and its hydrolyzate consists in that the crumbled animal bones are subjected to the maceration process with the acid of the concentration not higher than 34% at the time from 1 to 14 days, and during the maceration or after its termination, the calcium salts are separated from the

post-maceration lyes and the ossein obtained in this way, after the remaining acid is removed, preferably by rinsing with water, possibly containing the alkaline substance, is subjected to at least once extraction with the water at the temperature from 40 to 1200 ⁰ C. In order to obtain the gelatine, the water extract of the gelatine is cleaned by the use of the known methods, the extract is concentrated, possibly dried and milled, and in order to obtain the gelatine hydrolyzate, to the water extract there is added the proteolytic enzym which is later inactivated, and the extract is cleaned by the use of the known methods, concentrated and dried. The process of the invention is characterized in that the fat is removed from the reaction environment at the time of the maceration process and/or the extraction and/or after the termination of the maceration process and/or the extraction, by the separation of the water phase and the fatty phase or, in the case when the fat is removed after the termination of the extraction process, by the separation of the water phase containing the gelatine, the fatty phase and the solid phase or by the separation of the water phase containing the gelatine from the fatty phase combined with the solid phase.

The separation of the fatty phase and the water phase is carried out by the continuous or batch method.

Preferably the hydrochloric acid is used as the acid.

Before the stage of the maceration, the bones may be subjected to the proces of the muscle removal.

Preferably, the crumbled and possibly free of muscles animal bones are rinsed out with water.

The process for the maceration is carried out with or without mixing of the reactor content.

Preferably, the acid for the maceration process is delivered to the reactor from its bottom and/or from its side, and the post-maceration lyes are collected from the top of the reactor.

Preferably, the acid for the maceration process is delivered from the top of the reactor, and the post- maceration lyes are collected from the bottom and/or from the side of the reactor.

Preferably, the acid for the maceration process is delivered from the side of the reactor, and the post- maceration lyes are collected from the top and/or from the bottom and/or from the side of the reactor.

Preferably, bones are classified by the kind of the animal species and/or the kind of the bones.

Preferably, the proteolytic enzym is added in the quantity of at least 0,01% in relation to the dry mass of the gelatine present in the extract.

Preferably, the proteolytic enzym is inactivated by rising the temperature of the extract containing the gelatine.

The substance of the invention is the removal of the fat at the stage and/or after the stage of the extraction and/or the maceration, but not, as in the known processes, before the bone raw material is subjected to maceration with the acid. The change of the defatting stage to the phase of the maceration and/or extraction enables the significant reduction of the volume of the liquid wastes formed in process. It happens thanks to the elimination of a large

quantity of water introduced according to the process of the invention in which the whole first stage of the process for the preparation of the gelatine, namely the production of the defatted bone shot, is omitted. The bone material received from the meat processing plants and other sources should be only crumbled and then, without the preliminary defatting and without drying, is transfered to the production of the gelatine. Possibly, the bones are subjected to the process of the muscles removal if this process has not been earlier carried out in the meat processing plant. As a result, the whole module of the machines and devices for the preparation of the defatted bone shot and the installations and the production areas connected with them are eliminated. It leads to very big savings of the electric and thermal energy and a significant reduction of the costs connected with processing of the liquid wastes containing some quantities of the fat and proteins as well as a significant reduction of the costs for the preparation of the final product. The fat removed at the extraction stage contains water in a much lower quantity and thanks to that the fat separation may be much more easier and cheaper. The fat may be later used as the raw material in different applications, among others in the chemical industry.

The process of the invention is presented in more details in the realization example, and the schema of the process of the gelatine production is exemplary illustrated in the figure.

Example 1.

The pork bones from the meat processing plants and other sources along with the remaining meat tissue are

crumbled onto pieces of the size from 1 to 10 mm and rinsed out with cold water in order to remove the remainder of the blood. The crumbled bones are introduced to the reactor and flooded repeatedly with hydrochloric acid of the concentration of 3,8% at the volume ratio of the bones to the acid solution of 1:2,27 until the macerated bones is obtained. In the meantime, the calcium salts are separated from the post-maceration lyes by precipitation. After the termination of the maceration, which takes from 1 to 14 days, the ossein produced is washed with water in order to remove the acid until pH not ecxeeding 5 is obtained. Next, the ossein is flooded with water in the quantity of no more than 5 volumes of the ossein and heated to the temperature of 50 ⁰ C. The extraction process is carried out several times until the gelatine is transfered from the ossein to the water solution, and next the gelatine solution in the water is collected from the reactor. The fatty phase is periodicaly removed by pumping out from the upper part of the reactor. The water phase with the gelatine is transfered from the reactor to the tanks, and next it is cleaned, deionized, possibly by the ultrafiltration. Then, there is carried out the concentration in the evaporators, cooling, drying, milling, mixing and packing of the final product. The residue after the extraction process is withdrawn from the reactor in order to separate the remaining fat, the gelatine solution and solid parts. The gelatine obtained has the gel hardness of 253 bloom.

Example 2

The pork bones from the meat processing plants and other sources along with the remaining meat tissue are

crumbled onto pieces of the size from 1 to 10 mm. The crumbled bones are introduced to the reactor and flooded repeatedly with hydrochloric acid of the concentration of 4,2% at the volume ratio of the bones to the acid solution of 1:2,5 until the macerated bones are obtained. In the meantime, the calcium salts are separated from the post- maceration lyes by precipitation. After the termination of the maceration, which takes from 1 to 14 days, the ossein produced is washed with water in order to remove the acid until pH not ecxeeding 5 is obtained. Next, the ossein is flooded with water in the quantity of no more than 5 volumes of the ossein and heated to the temperature of 55°C. The extraction process is carried out several times until the gelatine is transfered from the ossein to the water solution, and next the gelatine solution in the water is collected from the reactor. After the termination of the extraction process the residue present in the reactor is transfered to a separate tank in which the preliminary collection of the fat is carried out by pumping out. Then, the residue is transfered to the decanter where the remainig fat, the water phase containing the gelatine and the solid phase are separated. The water phases containing the gelatine from the extraction stage and collected from the decanter are cleaned and deionized, possibly by ultrafiltration. The subsequent stages include concentration on the evaporators, cooling, drying, milling, mixing and packing of the final product. The gelatine obtained has the gel hardness of 302 bloom.

Example 3

From the pork bones coming from the meat processing plants and other sources the meat tissue is removed and then

they are crumbled onto pieces of the size from 1 to 10 mm and rinsed out with cold water in order to remove the remainder of the blood. The crumbled bones are introduced to the reactor and flooded repeatedly with hydrochloric acid of the concentration of 3,5% at the volume ratio of the bones to the acid solution of 1:2,25 until the macerated bones are obtained. In the meantime, the calcium salts are separated from the post-maceration lyes by precipitation and periodically the fatty phase is separated from the upper part of the reactor. During the maceration stage about 20% of the fat is removed. After the termination of the maceration, which takes from 1 to 14 days, the ossein produced is washed with water with the addition of the base in order to remove the acid until pH not ecxeeding 5 is obtained. Next, the ossein is flooded with water in the quantity of no more than 5 volumes of the ossein and heated to the temperature of 99°C. The extraction process is carried out several times increasing the temperature until the gelatine from the ossein is transfered to the water solution, and next the gelatine solution in the water is collected from the reactor. During each extraction the fatty phase is periodicaly removed by pumping out from the upper part of the reactor. The water phase with the gelatine is transfered from the reactor to the tanks. The residue after the extraction process is withdrawn from the reactor in order to separate the remaining fat, the gelatine solution and solid parts. The water phases containing the gelatine are cleaned, deionized, possibly by ultrafiltration, and concentrated on the evaporators, cooled, dried, milled, mixed and packed as the final product. The gelatine obtained has the gel hardness of 248 bloom.

Example 4

The pork bones from the meat processing plants and other sources along with the remaining meat tissue are crumbled onto pieces of the size from 1 to 10 mm. The crumbled bones are introduced to the reactor and flooded repeatedly with hydrochloric acid of the concentration of 4,2% at the volume ratio of the bones to the acid solution of 1:2,5 until the macerated bones are obtained. In the meantime, the calcium salts are separated from the post- maceration lyes by precipitation. After the termination of the maceration, which takes from 1 to 14 days, the ossein produced is washed with water in order to remove the acid until pH not ecxeeding 5,1 is obtained. Next, the ossein is flooded with water in the quantity of no more than 5 volumes of the ossein and heated to the temperature of 58°C. The extraction process is carried out several times until the gelatine is transfered from the ossein to the water solution, and next the gelatine solution in the water is collected from the reactor. After the termination of the extraction process, the residue present in the reactor is transfered to the separate tank in which the preliminary collection of the fat is carried out by pumping out. Then, the residue is transfered to the decanter where the remainig fat, the water phase containing the gelatine and the solid phase are separated. To the water phase containing the gelatine originated from the extraction ^' stage and collected from the decanter there is added the base in order to increase pH to 7,5 and then the proteolytic enzym Bacillus amyloliquefacies (Mulitfect P-3000) is added in the quantity of 0,5% in relation to the dry mass of the gelatine present in the water

phase. The base and enzym are added with the continuous mixing of the reactor content. After 1 hour, the temperature of the extract is increased to 80 ⁰ C in order to inactivate the enzym and then the extract is cleaned, concentrated and spray-dried.