JP2508641B2 - Method for producing blood meal having gel strength - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION "Industrial field of application" The present invention was applied to heat sterilization from a blood component having a gel strength such as plasma liquid or serum liquid obtained from animal blood without impairing the gel strength. The present invention relates to a method for producing blood meal having gel strength capable of obtaining blood meal.

"Prior art and problems" As is well known, blood of slaughtered cows, pigs, etc. has high protein content,
It is low in fat, and the amino acid composition contained in the protein is nutritionally excellent.

However, looking at the blood utilization of such slaughtered animals, only a small portion of low quality was produced by a simple treatment method such as boiling coagulation, and it is only used for fertilizers and feeds. However, most of the wastewater is treated as unused, which is a heavy burden on wastewater treatment.

Therefore, in recent years, from the standpoint of effective utilization of by-product substances of livestock animals and modernization of slaughterhouses, a blood treatment method that utilizes the excellent nutritional value of blood components and the various physical properties of blood components in food processing. As a result, the blood is centrifuged to separate the blood into blood cells and plasma, or the fibrin is removed from the blood, and the blood is centrifuged to separate the blood cells and serum, and the separated respective are spray-dried and freeze-dried. There is provided a method for obtaining a dried product, blood meal, without denaturing proteins by low temperature drying such as vacuum drying.

Plasma or serum obtained by this method has a pale yellow color, and the gel strength is in the state of dry blood powder, for example, 300 g / cm ² or more for pig plasma, 500 g / cm ² or more for bovine plasma, and originally, It can be an additive for foods in which viscoelasticity, strain, and texture are important. For example, it can be effectively used as a substitute egg white or the like.

However, in these conventional methods, since the concentration and drying temperature is low, sterilization by temperature is not considered, and the obtained plasma or serum product contains a large amount of general viable bacteria of about 10 ⁵ to 10 ⁷ per 1 g. In many cases, there were problems with food safety.

When blood meal is used as a food or a food processing material, the most important thing is safety as a food, and what needs special attention is contamination by microorganisms. Therefore, it is necessary to adopt a hygienic blood sampling method in the blood sampling step of obtaining the raw material of blood powder, and also in the subsequent separation and drying step,
It is important to minimize the contamination of microorganisms from the outside and the proliferation of microorganisms in the process. However, it is difficult to completely suppress these microorganisms in the manufacturing process. Therefore, sterilization of the obtained blood powder is important, and as one method of sterilizing the blood powder, gas sterilization with ethylene oxide, propylene oxide or the like is known. This sterilization method is capable of sterilization without causing protein denaturation and deterioration of blood powder solubility and gel strength, but the problem of residual toxicity of the used gas remains unsolved. Another sterilization method is a heat sterilization method. Although this sterilization method is an excellent sanitary sterilization method, it causes heat denaturation of proteins, lowers gel strength, and causes a significant decrease in commercial value of blood meal.

By the way, prior to the present invention, the present applicant has found that blood components such as blood or plasma are soluble in water (solubility).
And a method for obtaining a sterilized dry product without lowering the heat coagulability by more than 50% (Japanese Patent Publication No. 60-15). In this method, blood or each blood component separated by a centrifuge or the like is dried at a low temperature to obtain a dry product having a water content of 30% by weight or less, and the dry product is 80 to 16% for each water content.
Although it is heated to a temperature of 0 ° C. and sterilized, the gel strength, which is a physical property as an additive for which viscoelasticity, strain, and texture are important, was not considered.

Gel strength is a phenomenon different from solubility (water solubility) and thermal coagulability, and is, for example ,. Blood cells have a reddish brown color and have a nutritionally excellent composition similar to that of plasma and serum. From the viewpoint of protein content, it is approximately 90% of the dry matter equivalent of plasma and serum.
Although superior to 70-75%, blood cells originally do not have gel strength. In addition, even if the solubility and thermocoagulability can be maintained when obtaining a dry product of plasma or serum, it is often impossible to measure the gel strength. Even when obtaining a dry product, the solubility is maintained at about 80%. Even if you can do it, it will be very low.

The present inventors, as a result of various studies in view of the above circumstances,
The gel strength of plasma, serum, etc. obtained by the low temperature drying is
It was found that if the water content is 12% or less, the product temperature is limited to 110 ° C or less, and if heated while appropriately ventilating and stirring, the temperature hardly decreases.

The present invention has been made based on the above findings, and an object thereof is to provide a method for producing blood meal capable of performing sterilization (commercial sterilization) of general live bacteria, Escherichia coli, etc., and having almost no decrease in gel strength. To do.

"Means for Solving Problems" The method for producing blood powder having gel strength according to the present invention,
Dry blood component with gel strength obtained from blood is stirred at an initial water content of 3 to 12 weight with continuous or intermittent ventilation in the sterilization chamber, and 90 to 110 ° C by indirect heating.
The method is characterized by obtaining sterilized blood meal by heating to the product temperature.

[Operation] According to the above method, it becomes possible to sterilize the powder of plasma, serum, etc. obtained by low-temperature drying sufficiently without substantially lowering the gel strength.

Hereinafter, the present invention will be described in more detail with reference to examples.

[Example] As shown in Fig. 1, blood is collected from the livestock animal 1 in a hygienic manner with a tubular knife or the like, and at the same time, an anticoagulant such as an aqueous solution of sodium citrate in the anticoagulant tank 2 is immediately applied to the blood. Mix about 0.5% by weight as sodium citrate to prevent blood coagulation. The collected blood is temporarily stored in the inspection tank 4 after removing contaminants such as meat pieces, fat pieces, and hair mixed through the strainer 3. After checking the presence or absence of slaughter of illness by inspecting the carcass while storing it in the inspection tank 4, only blood confirmed to be hygienic was passed through the next heat exchanger 5 and cooled. Then, it sends to the centrifuge 6. Separation is performed by this high-speed continuous centrifuge 6, and the light liquid portion is collected as plasma liquid and the heavy liquid portion is collected as blood cell liquid. The obtained plasma liquid is sent to the next plasma vacuum low-temperature dryer 7, where the product temperature is preferably 40 ° C. or lower when the concentration of the plasma liquid is low.
Care should be taken not to heat denaturate the proteins in the plasma solution by drying at a low temperature while keeping the product temperature at 50 ° C or lower even when the concentration is high, such as 50% or higher. Regarding the degree of drying in the vacuum low-temperature dryer 7, the degree of drying is adjusted in consideration of the sterilization step of the next step, and the drying is stopped at an appropriate moisture level. The dried plasma powder is pulverized by a pulverizer 8 to a size of usually 60 mesh under.

When dry serum is obtained instead of dry plasma, the capture element and the like are gently stirred in the blood to remove the fibrin in the blood from the blood, and then the blood is separated into serum and blood cells by a centrifuge. Alternatively, the plasma fluid separated by the centrifuge is stored in a storage tank for a while to coagulate the fibrin, and the coagulated fibrin is removed from the fibrin by sieving, filtering, or using a strainer to obtain a serum solution. The liquid may be dried in a vacuum low temperature dryer as described above.

The above-mentioned dried plasma and dried serum correspond to the dried blood component of the present invention.

In order to effectively carry out the present invention, common sense precautions regarding the handling of foods containing protein in the blood collection step, separation step and drying step before the next sterilization step are important. That is, when collecting blood, be careful not to mix microorganisms into the blood as much as possible, and after cooling blood, perform sufficient cooling, preferably at 4 ° C or lower to prevent growth of microorganisms in blood after collecting blood. Is important. In the separation step, the temperature of the blood rises in the centrifuge, so it is necessary to cool it again to 4 ° C or lower in the storage tank (not shown) that stores the separated liquid. In the drying process, it is necessary to heat both plasma and serum in order to evaporate water, but at this time, keep the product temperature at 50 ° C or lower, preferably 40 ° C or lower, and keep it at a temperature at which protein denaturation occurs. It is necessary to avoid going up as much as possible.

As explained above, the solubility of both dried plasma and dried serum, which are dried blood components produced with great care, is
%, And the plasma powder gel strength varies depending on the type of slaughter, but is 500 g / cm ² or more for cattle and 300 g / cm ² for pigs.
Above all, it is an excellent intermediate product in terms of physical properties, but in terms of the number of microorganisms, it is approximately 10 ⁵ per 1 g of blood meal.
In many cases, it contains a large amount of microorganisms of up to about 10 ⁷ places.

Next, the dried plasma and dried serum are heated and sterilized by a heat sterilizer 9.
Can be put in. The term "heat sterilization" as used herein includes commercial sterilization in which microorganisms are sterilized to the extent that they can be used as food materials without causing any trouble. That is, this is a method in which the number of coliform bacteria, which is an index of harmful bacteria, is set to a target value (30 as the most probable number per 100 g) or less without significantly lowering the physical properties of blood powder.

Gel strength is an important physical property change that occurs during heat sterilization of dried plasma and serum. Gel strength is important for increasing the value of plasma and serum in food and food processing.

 The outline of the method for measuring the gel strength is shown below.

Dissolve blood meal in distilled water to prepare a solution with a solid content of 10%. This is filled in a vinylidene chloride tube having a diameter of 30 mm, and degassing is performed from the upper part of the tube with a vacuum pump. The tube is then sealed and placed in a hot water bath at a temperature of 90 ° C for 30
Heat to solidify for minutes. After heating and solidifying, cool to 15 ° C, peel off the vinylidene chloride tube, and measure the breaking point of a cylindrical sample cut into a length of 30 mm using a rheometer. In the experimental example described later, NRM-2 manufactured by Fudo Kogyo Co., Ltd.
002J, a disk type plunger (for viscoelasticity) with a diameter of 1.5 cm was used as an adapter. The measurement is performed 5 times for each sample. Except for the highest value and the lowest value, the average value of three measured values is calculated, and the gel strength is calculated by the following calculation formula.

The load scale of the measuring instrument NRM-2002J is displayed in percentage, and the load at 100% can be switched. Therefore, the above equation is also displayed as

As the main items of the technical configuration of this sterilization process, appropriate product temperature during heat sterilization, maintenance of time and adjustment of initial water content of dried blood component that is the sterilization object, and in relation to the selected sterilizer, Appropriate controls such as temperature adjustment of the heating medium for heating the sterilizer, ventilation in the sterilization chamber, stirring, etc. Hereinafter, each of these items will be described in detail.

(I) Product temperature during sterilization The product temperature during sterilization is approximately 90 to 110 ° C,
It is suitable to maintain the temperature at about 95 to 105 ° C. If the number of microorganisms contained in the dried blood component is small, or if the contained organisms are microorganisms that are easy to sterilize, at 90 ° C or so, the target may be achieved sufficiently, but the number of microorganisms is large or it is difficult to sterilize. When there are many microorganisms, it is necessary to keep the product temperature at around 110 ° C. The higher the product temperature is, the better the bactericidal effect is, but the gel strength is apt to be lowered, so that the temperature is preferably 95 ° C to 105 ° C.

Regarding the maintenance time of the product temperature, in the case of batch type and continuous type, furthermore, the jacket of the sterilizer room, the indirectly heated rotary type for heat sterilization by passing the heat medium such as steam or mineral oil through the coil or the blade of the stirrer, Differs depending on when using a paddle type sterilizer. In the inter-heat batch method, the product temperature rises with time until the temperature rises, and the sterilizing effect is exerted during that time as well. Therefore, in some cases, the temperature may be lowered immediately when the predetermined product temperature is reached. As described above, it is difficult to specify the sterilization time so accurately. But,
In the case of the batch type of indirect heating, it is good to carry out for about 10 minutes after raising the temperature to about sterilization temperature, and in the case of the continuous type of indirect heating, the residence time in the sterilizer may be carried out for about 20 minutes to 60 minutes. .

(Ii) Initial water content of dried blood components The initial water content of dried blood components is very important. When heat sterilization is started with a low initial water content of less than 3% by weight, the bactericidal effect is inferior, and when the initial water content exceeds 12% by weight, the bactericidal effect is good, but the gel strength decreases and the quality deteriorates. To do. Therefore, the range of the initial water content at which effective sterilization can be carried out without causing a decrease in gel strength is 3 to 12% by weight, preferably 4 to 10% by weight, more preferably 5 to 6% by weight.

Generally, when a plasma liquid or a serum liquid is dried by vacuum drying or the like, it has a strong hygroscopic property, and the water content of the dried blood powder rarely becomes 3% by weight or less in a normal manufacturing operation. When the initial water content is less than 3% by weight, in order to effectively sterilize, spray moistening is performed, and the mixture is further well mixed by stirring to uniformly moisturize it, and after heating it to a predetermined water content, heat it. It is preferable to carry out sterilization. In addition, in this specification, the water content is a value represented by the following equation.

(Iii) Grinding of dried blood component As a method for drying plasma liquid or serum liquid that is a blood component having gel strength, a spray dryer or a stirring type vacuum dryer is used, but these are dried blood powder. (Dry blood component) has irregular particle size, and
In terms of the bactericidal effect, it is better to pulverize the dried blood component in advance, pulverize it to 60 mesh under and sterilize it. If crushed after sterilization, the blood powder after sterilization may be contaminated by microorganisms again by the crushing operation, and if the particle size of blood powder is too large, the amount of heat transfer to the inside will be small and the effect of sterilization may not be good. .

(Iv) Ventilation in sterilization chamber In the indirect heating type sterilizer, when the sterilization is hermetically closed and heat sterilized, water contained in the dried blood component evaporates, and a partial heat and heat sterilization occurs, resulting in saturation. There is a possibility that the gel strength of the dried blood component may be reduced by the high temperature steam close to the state. Therefore, it is necessary to send an appropriate amount of inert gas such as nitrogen or air into the sterilization chamber and expel the generated water vapor as appropriate to ventilate the sterilization chamber and prevent the gel strength from decreasing. The amount of gas to be ventilated differs depending on the scale of the device and the agitation speed of the dried blood components. Generally, in small-scale devices, the heat transfer area per dried blood component is large, so the heat transfer is fast and the required gas The amount of ventilation of is also large.

On the contrary, when the scale is increased, the heat transfer area per dried blood component is small and the heat transfer is slowed down, so that the required air flow rate is small. As an example, when sterilizing about 100-200 g of dried blood components, the required aeration amount is about 0.1-0.2 Nl per minute of dried blood components, but on a scale of 30-40 Kg. Ventilation around 0.02Nl is enough. The required aeration amount is also affected by the speed of stirring. Therefore,
It is necessary to confirm the required air flow rate by experiment for each device and scale used, but it is necessary to confirm that
Aeration of 0.02 to 0.2 Nl is required.

(V) Temperature of heating medium In the above indirect heating, in which the heating medium such as steam or mineral oil is passed through the jacket of the sterilization chamber or the coil of the blade of the stirrer to raise the temperature of the dried blood component, the temperature of the heating medium is the sterilization product temperature. The higher the temperature difference between the product temperature and the heating medium, the easier it is to raise the temperature.However, if it is too high, the temperature of the heat transfer surface becomes too high and the dry blood component is heated at the contact surface, causing gelation. The temperature of the heat transfer medium must be carefully considered because it may cause reduction in strength.

(Vi) Heating temperature of ventilation inflow gas Although the temperature of the inflow gas for ventilating the indirect heating type sterilization room is not particularly problematic even at room temperature, it is better to send the preheated gas to raise the product temperature. There is an advantage that the heat transfer surface is small and there is no need to raise the temperature of the medium too much.
However, if the temperature is too high above the sterilization temperature, it directly contacts the dried blood component as the substance to be sterilized, resulting in a decrease in gel strength, which is not preferable. The preheating temperature of the ventilation inflow gas is preferably 110 ° C. or lower. Also, the cheapest air may be used as the ventilation gas for ventilation. For the purpose of commercial sterilization, the inflowing air does not need to use sterilized sterile air.

(Vii) Stirring If sterilization is performed without stirring the dried blood components at all, steam will be retained in the sample, which will cause a decrease in gel strength.

According to the above technical factors, it is possible to achieve the purpose of commercial sterilization by performing heat sterilization of dried blood components, and also to suppress the decrease in gel strength as much as possible, which is an excellent raw material for food or food processing. As a result, it is possible to manufacture blood meal with high added value.

Blood meal with gel strength sterilized in this way,
Bagging is performed by the bagging machine 10 if necessary. In addition, in FIG.
Reference numerals 11, 12, 13, and 14 represent a vacuum low-temperature dryer, a crusher, and a bagging machine, respectively, which target blood cell fluid.

Next, an example of an experiment conducted to confirm the effect of the above-mentioned embodiment will be described.

The apparatus used for this experiment is a modification of a known rotary evaporator (RE-45 type, manufactured by Yamato Scientific Co., Ltd.). The schematic configuration of this experimental apparatus is shown in FIG. In the figure, reference numeral 20 is a compressed air storage tank for storing compressed air from a compressor not shown, 21 is a pressure gauge, 22 is an air inlet thermometer, 23 is an air flow meter, 24 is a connecting rubber tube for air feeding, and 25 is heating. Oil bath, 26 heating medium, 27 sample, 28 eggplant-shaped flask, 29 bar thermometer, 30 air inlet pipe, 31 air exhaust pipe, 32 eggplant-shaped flask 28 rotary joint 36
A bearing main part which is supported while rotating through, a cooling pipe 33, a rubber plug 34, and an exhaust connecting rubber pipe 35. This rotary evaporator is usually used for concentrating or drying the sample 27 in the eggplant-shaped flask 28 under vacuum, but in the case of this experiment, the switching cock in the rubber stopper 34 was used. removal. Attach this rubber stopper 34,
Further, a rod-shaped thermometer 29, an air inlet pipe 30, and an exhaust pipe 31 are attached to the rubber plug 34. A bar thermometer 29
The temperature sensation part was inserted into the sample 27 of the eggplant-shaped flask 28, and the tip of the air inlet tube 30 was enlarged so that the air was widely distributed on the surface of the sample 27. Further, the air discharge pipe 31 also reaches the inside of the eggplant-shaped flask 28 in the same manner, and the tip end thereof has a structure that is widened so that the air containing the moisture generated from the sample 27 can be easily collected. Regarding the installation positions of the tips of the air inlet pipe 30 and the air outlet pipe 31 inside the eggplant-shaped flask 28, the air inlet pipe 30 is closer to the surface of the sample 27. The tip of the air discharge pipe 31 is located far from the surface of the sample 27 so that the sample scattered by the incoming air does not flow out of the air discharge pipe 31 as much as possible.

 The outline of the operation method of this device will be described below.

An appropriate amount of sample (plasma powder or serum powder) 27 is collected in an eggplant-shaped flask 28. The temperature of the heating oil bath is raised to a constant temperature in advance. Compressed air is sent to the compressed air storage tank 20 to measure pressure and temperature. Attach the eggplant-shaped flask 28 to the rotary joint 36 and rotate it in an oil bath. Air flow meter 23
, A predetermined air is sent through the air inlet pipe 30, and the exhaust air is exhausted through the air exhaust pipe 31. The temperature of the sample 27 is measured by a rod-shaped thermometer 29 inserted in the sample 27.
The amount of air sent in was corrected to the standard state (1 atmospheric pressure, 0 ° C.) by the measured temperature and pressure and displayed. The gel strength was measured by the method described above.

(Experimental Example 1) In order to confirm the influence of the product temperature and the gel strength of the dried blood component when heat sterilized, bovine blood (0.5% by weight of sodium citrate as an anticoagulant was added to blood during blood collection) ) At 4000 rpm for 20 minutes in a centrifuge tube centrifuge,
The separated plasma liquid is vacuum dried while keeping the product temperature at 40 ° C or lower,
The obtained dry plasma was tested by the above-mentioned experimental apparatus (Fig. 2).

 The experimental conditions are shown below.

・ Flask used ・ ・ ・ 1 volume pleated eggplant flask ・ Sample type ・ ・ ・ Bovine dried plasma (water content 7%, gel strength)
584g / cm ² , particle size 60 mesh under) ・ Sample filling amount ・ ・ ・ 120g ・ Sterilization temperature ・ ・ ・ 80, 90, 95, 100, 105, 110, 120 ℃
(Product temperature) ・ Sterilization time ・ ・ ・ 10 minutes ・ Ventilation air (unsterilized) amount and temperature ・ ・ ・ 0.15Nl / g ・ mi
n, 20 ° C ・ Number of rotations ・ ・ ・ 6r.pm ・ Analysis items ・ ・ ・ Water, gel strength, general viable cell count, coliforms Experimental results are shown in Table 1 below. From the results in this table, it is understood that the product temperature in the range of 90 to 110 ° C. is appropriate in the case of bovine dried plasma. In addition, as a result of performing a similar test on the dried bovine serum obtained by similarly removing the fibrin from the bovine blood and centrifuging the same, the result was almost the same as the case of plasma. Moreover, almost the same results were obtained for dried pork plasma powder and dried pork serum powder.

(Experimental Example 2) In order to sterilize by heating without lowering the gel strength, the initial water content of the dried blood component before heat sterilization is important.

The results of an experiment investigating the effect of initial water content on heat sterilization using pig plasma powder and serum powder are shown below. The experiment apparatus shown in FIG. 2 was used for the experiment. Pig blood (At the time of blood collection, 0.5% sodium citrate was added to the blood as an anticoagulant.
Was added (by weight%) to a centrifugal separator at 4000 rpm for 20 minutes, the separated plasma solution was vacuum dried at a product temperature of 50 ° C. or lower, and an experiment was performed using the obtained pig dried plasma. The experimental conditions are shown below.

・ Flask used ・ ・ ・ Eggplant flask with 1 volume fold ・ Sample type ・ ・ ・ Pig dried plasma [initial water content 14, 12, 10,
8, 6, 4, 3, 2% by weight, particle size 60 mesh under] -Sample filling amount ... 120g-Sterilization temperature ... 110 ° C (article temperature) -Sterilization time ... 10 minutes-Ventilation air (None Sterilization) Amount and temperature: 0.15 Nl / g ・ mi
n, 20 ° C ・ Number of rotations ・ ・ ・ 6r.pm ・ Analysis items ・ ・ ・ Gel strength, general viable cell count, coliforms In addition, dried pork plasma has a water content of 7.5% by weight and a gel strength of 351g /
Since it was cm ² , the dried plasma with 8-14 wt% water used in the experiment humidified sterile water, and for the water sample of 6 wt% or less, use a vacuum dryer in which the sample container was sterilized in advance. It was dried and adjusted.

 The experimental results are shown in Table 2 below.

(Hereinafter, margin) As shown in the above table, when the initial water content is 2% by weight or less, the quality is good, but the bactericidal effect of the general viable cell count is poor. When the water content is 12% by weight or more, the bactericidal effect is good, but the gel strength decreases. The initial water content is 3 to 12% by weight, although there are some differences depending on the sterilization conditions such as sterilization temperature, ventilation volume, and rotation speed.
The range of should be kept.

Fibrin was removed from the pig blood to which the anticoagulant had been added, centrifugation was carried out, and the same experiment was performed on the dried pig serum obtained by vacuum drying. The experimental conditions are shown in Table 3 below. Is the same as for pig dry plasma.

As shown in the table above, the tendency of dried pig serum was almost the same as that of dried pig plasma. The same experiment was performed with the dried bovine plasma and serum of Experimental Example 1, but similar results were obtained.

If the initial water content is too low as a tendency in heat sterilization, the effect on quality deterioration is small, but the desired sterilization effect is poor. Further, if the initial water content is too high, the bactericidal effect is good, but the gel strength is greatly reduced, and the commercial value is reduced. The initial water content is 3 to 12% by weight, preferably 4 to 10% by weight, more preferably 5 to 6% by weight.

(Experimental Example 3) Effect of bactericidal effect due to difference in particle size of dry plasma Pigment dried plasma having a water content of 6.7% by weight and gel strength of 374 g / cm ² obtained by the same method as in Experimental Example 2 was divided by a filter for particle size. An experiment was conducted for each particle size using the above-mentioned experimental apparatus (Fig. 2).

 The experimental conditions are shown below.

・ Flask used ・ ・ ・ 1 volume pleated eggplant flask ・ Sample type ・ ・ ・ Dry pig plasma (water 6.7% by weight, gel strength 374 g / cm ² ) ・ Particle size ・ ・ ・ 4 mesh under 20 mesh on, 20 mesh under 60 Mesh on, 60 mesh under ・ Sample filling amount ・ ・ ・ 120g Sterilization temperature ・ ・ ・ 105 ℃ ・ Sterilization time ・ ・ ・ 10 minutes ・ Ventilation air (unsterilized) amount and temperature ・ ・ ・ 0.15Nl / g ・ mi
n, 20 ° C ・ Number of rotations ・ ・ ・ 6r.pm ・ Analysis item ・ ・ ・ Gel strength, general viable cell count The experimental results are shown in Table 4 below.

As shown in the above table, the finer the crushed particles, the better the bactericidal effect. It is better to sterilize after the particle size is preferably 60 mesh or less.

(Experimental Example 4) In the indirect heating type heat sterilization, the sterilizing effect and the gel strength of dry plasma were compared between the case where the sterilization chamber was ventilated and the case where no ventilation was performed at all. A bovine dried plasma having a water content of 7.0% by weight and a gel strength of 579 g / cm ² obtained by the same method as in Example 1 was used by using the above experimental apparatus (FIG. 2).

 The experimental conditions are shown below.

・ Flask used: Eggplant flask with 100 ml folds ・ Sample type: Dry cow plasma (water content: 7.0% by weight, particle size: 60)
Mesh under) ・ Sample filling amount ・ ・ ・ 15g ・ Sterilization temperature ・ ・ ・ 105 ℃ (Product temperature) ・ Sterilization time ・ ・ ・ 10 minutes ・ [Ventilation air (unsterilized) amount and temperature] ・ ・ ・ 0.15Nl / g
・ Min, 20 ℃ ・ Rotation rate ・ ・ ・ 6r.pm ・ Analysis item ・ ・ ・ Gel strength, general viable cell count The following table 5 shows the experimental results.

As is clear from the experimental results in the above table, the bactericidal effect of general viable bacteria and Escherichia coli was good in both indirect heating type heat sterilization with and without ventilation. Thermospore-forming spores were negative in the sample before sterilization. However, with respect to the gel strength, there is little decrease in the case of ventilation, and the product quality target value can be almost maintained, but in the case of no ventilation, the gel strength is remarkably deteriorated.

An experiment was carried out on the dried serum in the same condition, and the similar result was obtained. By ventilating both dry plasma and serum, it was possible to suppress the decrease in gel strength due to heat sterilization and maintain the target value of product quality. Regarding thermostable bacteria, it is generally said that the effect of heat sterilization is small, but by using fresh blood and performing hygienic pretreatment, values below the target value can be obtained at the stage of dried blood powder. It was confirmed that this experiment also showed a negative value of 300 / g or less at the stage of dry plasma before sterilization.

(Experimental Example 5) Regarding the influence of the temperature of the gas for ventilating the sterilization chamber necessary for the indirect heat sterilization, the water content was 6.7% by weight, the gel strength was 385 g / cm ² , and 60 mesh under was obtained by the same method as in Experimental Example 2. An experiment was carried out using the above-mentioned experimental apparatus (FIG. 2) using pig dry plasma. As a result, by using heated air at 80 to 120 ° C, it took 10 to 20 minutes to reach the target product temperature, but was shortened to 5 minutes or less.

However, if the temperature of the heated air is too high, the quality is affected. Therefore, it is preferable to set the temperature to 110 ° C. or lower, like the product temperature. The experimental results of the influence of the heating air temperature on the gel strength are shown in Table 6 below.

During heat sterilization, the temperature of the dried plasma was raised to 110 ° C., kept at that temperature for 10 minutes, and then lowered.

Therefore, the air blown to the sterilization chamber in the indirect heating type heat sterilization may be at room temperature, but sending preheated air requires less time to raise the temperature and lowers the temperature of the heating medium.

 The conditions of the above experiment are shown below.

・ Flask used ・ ・ ・ Eggplant flask with 1 fold ・ Sample type ・ ・ ・ Pig dried plasma (water 6.7% by weight, particle size 60)
Mesh under) ・ Sample filling amount ・ ・ ・ 150g ・ Sterilization temperature ・ ・ ・ 100 ℃ (Product temperature) ・ Sterilization time ・ ・ ・ 10 minutes ・ Ventilation air (unsterilized) amount ・ ・ ・ 0.15Nl / g ・ min ・ Ventilation Air temperature ・ ・ ・ 80, 90, 100, 110, 120 ℃ ・ Rotation rate ・ ・ ・ 6.rpm (Experimental example 6) In order to investigate the influence of stirring in heat sterilization, the water content was 6.7% by weight and the gel strength was 385 g /
Experiments were carried out with the experimental apparatus (FIG. 2) using cm ² of pig dry plasma.

 The experimental conditions are shown below.

・ Sterilization temperature ・ ・ ・ 100 ℃ (Product temperature) ・ Flask used ・ ・ ・ Eggplant flask with 1 fold ・ Sample type ・ ・ ・ Pig dried plasma (water 6.7% by weight, particle size 60)
・ Mesh under) ・ Sample filling amount ・ ・ ・ 120g ・ Ventilation air (unsterilized) amount and temperature ・ ・ ・ 0.16Nl / g ・ mi
n, 20 ° C.-rotation speed ... 0, 1, 2, 5, 10, 21 r.pm-oil bath temperature ... 120 to 125 ° C. Table 7 shows the experimental results.

As shown in the table above, the gel strength deteriorates at the number of revolutions of 0, but the deterioration of the product temperature can be prevented even if the sample moves even at one revolution per minute. Note that when the stirring is small, overheating may occur in the boundary film portion, so it is better to control the heating medium temperature to be somewhat lower.

As a method of stirring the dried blood component, there are a method of rotating the container itself containing the sterilized sample as shown in the experimental apparatus (FIG. 2) and a method of placing the stirrer in the sterilization chamber. The method of placing the stirrer in the sterilization chamber is more advantageous in terms of scattering of the sample during ventilation.

Although the vacuum drying method was used to obtain the dried blood component in the above-mentioned examples, the present invention is not limited to this, and a spray drying method or a freeze drying method may be used. Further, in the indirect heating type heat sterilization, ventilation in the sterilization chamber may be performed intermittently, and instead of the method of sending gas to the sterilization chamber with a blower, ventilation is performed by sucking gas in the sterilization chamber. Of course, it may be done.

As described above, the method for producing a sterilized blood meal having a gel strength such as plasma powder and serum powder has been described.As is apparent from these, according to the method of the present invention, the gel strength such as the food quality and the food processing material quality can be improved. Effective sterilization can be performed without deteriorating important physical properties.

[Brief description of drawings]

FIG. 1 is a manufacturing process diagram of blood powder, and FIG. 2 is a configuration diagram of an apparatus used for an experiment of the method of the present invention.

 ─────────────────────────────────────────────────── ─── Continued Front Page (72) Haruhiko Nagasawa, 1-9-3 Kamatahonmachi, Ota-ku, Tokyo Inside Niigata Iron Works Co., Ltd. (72) Inko Miko Nishimura 1-3-9, Kamatahonmachi, Ota-ku, Tokyo Niigata Iron Works Co., Ltd. (56) Reference JP-A-53-75356 (JP, A)

Claims (7)

(57) [Claims] 1. A dry blood component having a gel strength obtained from blood, which is agitated while continuously or intermittently ventilating a sterilization chamber in a state where the initial water content is 3 to 12% by weight. A method for producing blood meal having gel strength, which comprises sterilizing blood meal by heating to a product temperature of 90 to 110 ° C. 2. The method for producing blood powder having gel strength according to claim 1, characterized in that the dried blood component is dried by keeping its temperature at 50 ° C. or lower. 3. The method for producing blood powder having gel strength according to claim 1, wherein the dried blood component is crushed to 60 mesh or less. 4. The dry blood component is a dry plasma and / or dry serum component.
A method for producing blood meal having gel strength according to the item. 5. Ventilation in the sterilization chamber is set to 0 per 1 g of dried blood components.
The method for producing blood powder having gel strength according to claim 1, which is carried out by passing a gas of 02 to 0.2 Nl / min through the sterilization chamber. 6. The blood powder having gel strength according to claim 1 or 5, wherein ventilation in the sterilization chamber is performed by passing a gas heated to 110 ° C. or lower through the sterilization chamber. Manufacturing method. 7. The gas according to claim 1, wherein the gas passed through the sterilization chamber for ventilation is air.
Item 7. A method for producing blood meal having a gel strength according to item 6 or 6.