CS159384A2 - Zpusob upravy mikrobialnich bunecnych ot - Google Patents

Description

The present invention relates to the processing of microbial cell masses in order to convert cell mass into a form that is more suitable for further processing.

Microbial cell masses are valuable protein sources but are not useful for human nutrition without further modification. Thus, if the bacterial cell masses which contain a considerable amount of nucleic acids are to be removed, these can be removed to avoid health problems. Due to the odor and taste as well as the reason for the durability of the lipids, it is also necessary to remove the lipids as completely as possible. Extraction procedures have already been proposed to remove these interfering components. However, these extractions result in greater or lesser excretion of solids and / or protein losses.

It has now been found that the processing of microbial cell masses is greatly facilitated if the sinter material is heat treated prior to extraction of lipids and nucleic acids. Thus, the object of the invention is to provide a method for treating microbial cell masses in which the dried cell mass is subjected to

for 3 to 40 minutes of heat treatment at a temperature of 105 to 160 ° C, with thermal energy being transmitted, radiation or convection by a gaseous medium. Preferred embodiments of the process of the invention are explained in more detail below. *

The duration of the heat treatment depends on the starting material, in particular on the residual moisture contained therein, and of course on the temperature at which the tapping is carried out. This period is preferably 3 to 40 minutes, particularly preferably 5 to 20 minutes at a temperature range of 105 to 140 ° C.

The microbial raw biomass which is considered to be the starting material should have a water content of 10% by weight, preferably from about 3 to 5% by weight, which can easily be achieved by conventional contact drying procedures, in particular roller drying or convection drying. , such as spray drying, which processes the product. Preferred are the dried raw materials with a bulk density above 400 g / l, a constant weight in the shaken state of 500 g / liter and a particle size above 40 µm in an amount of 75% · Preferred is a crude product which can be obtained by the process described in German Patent Specification 2 633 451. '-1-'

The process ae may be carried out in all conventional devices in which thermal energy is a pre-batch, radiation or convection using a gaseous medium *

The products obtained by the process according to the invention have a number of advantageous properties *

The improvement in mechanical properties is demonstrated not only by increased durability and shelf-life, but also by easier filling and dosing, in particular by improved behavior in the subsequent extraction of lipids and nucleic acids. The following procedures require multiple separation of solids and liquids by filtration, blasting, using membrane filters and / or reverse osmosis. Surprisingly, the improvement in mechanical properties is not associated with impaired extraction behavior, not only does the physiological properties of the final product affect adversely.

Particularly preferred is the process according to German Patent No. 26 33 666, in which the content of lipids and nucleic acids in the cell masses is reduced in a two-stage extraction process. First, the cell mass is treated with an extraction mixture consisting of ammonia and a polar solvent from the group of lower aliphatic alcohols, lower glycols or lower alkyl ethers of low molecular weight glycol which contains at most 30% by weight of water (based on solvent). . The ammonia content is preferably 1 to 10% by weight, based on the amount of solvent. At this first stage, the lipids are extracted. This is followed by a second extraction step in which nucleic acid water is extracted to the maximum extent. Thus, about 60 to 80% of the pure product is obtained from the raw material used.

If a treatment according to the invention is carried out prior to this extraction process, then 10 to 30% higher solids yields are achieved without adversely affecting the extraction result with respect to the removal of lipids and nucleic acids. In addition, the biological properties of the final product are significantly improved. From German Patent No. 2,745,954 a process is known in which a contaminated natural microbial protein is exposed in an aqueous medium to a temperature of about 40 to 150 ° C until the protein is precipitated, whereupon the precipitated protein is separated off and enzymatically degraded Thus, in this process, heating to precipitate the protein from its aqueous solution serves to separate from other substances remaining in the solution. From DE-OS 26 51 464, a process is known to disrupt aqueous suspensions of microbial cellular matter at relatively high temperatures. and pressures. Preferably, temperatures from about 60 ° C to about 200 ° C are used. Cell disruption is carried out at 60 ° C for about 20 hours and at 200 ° C for about 2 hours. The released protein is then separated from known disrupted cell processes. Hence, heating is used to convert the protein into an aqueous solution. Therefore, it has not been possible to derive from these known processes that the heat treatment of dry bacterial cell masses will result in a product with improved technical properties for further processing, which will be advantageous in the subsequent extraction process. Furthermore, the products obtained by this process could not be expected to have improved nutritional physiological properties. In the following examples, the invention is explained in more detail, but its scope is not to be construed as limiting

with a bulk density of 544 g / liter, with a constant weight in the tapped state of 597 g / liter and with a particle size of greater than 40 µm in an amount of 90%, in a fluidized bed at a temperature of 160 ° C in contact with siphoned air. The temperature of the product is maintained at 120 DEG C. for 10 minutes. The product obtained after cooling exhibits substantially reduced abrasion and better storage properties under mechanical stress.

Extracting 1Gg / µg of the product thus obtained according to Example 1 of German Patent Specification No. 26,333,666 results in 75 kg of pure product having a nucleic acid content of 1.5% by weight, with a fat content of 0.8% by weight and a protein content of more than 1% by weight. 90% <·

Thus, the extracted product has the same content of solids and nucleic acids as the product of Example 1 of German Patent 26 33 666, but the protein yield is 15% higher due to the practically quantitative solids yield in the extraction step.

Concludes 2

Determining the PER value (PER = protein efficiency ratios of protein utilization)

The product which has been heat treated according to Example 1 is compared and further extracted (the product of the invention) with a product that has been extracted without prior heat treatment (comparator) in terms of PER.

The investigated products are compared on the basis of semi-synthetic feed (cf. Gesellchaft fur

Ernahrungsphysiologie der Haustiere, Arbeitskreis fur Proteinbewertung, Vorsehrift zur Proteánbewertung in Versuchen an waJScheanden Ratten, Zeitschr.vz

Tierphysiol. Tierern. Futtermittelkde., 19, (1964), &lt; RTI ID = 0.0 &gt; 30O3308, &lt; / RTI &gt; For the control purposes, casein feed was prepared. The protein or casein carrier was always the only source of protein in the feed. The corresponding nitrogen concentration of the total acids was 10% pure protein. All feeds were supplemented with DL-methionine. Male animals (Dawley strain) with an average weight of 70 g at the start of the experiment were used as experimental animals. 12 animals by weight are selected per mono to obtain uniform starting weights. The results are summarized in the following table. Ί 'a b u 1 k a

X '---' w * · X

group examined medium weight PES product increment in g after absolute 21 days rela- tive absolute relative A casein 136.7 100 3.56 100 B according to the invention 156.8 114.7 · 4.46 125.3 C comparative Product 136.5 99.9 3.82 107.2

Claims (2)

OBJECT OF THE INVENTION A process for the treatment of microbial cell masses, characterized in that the dried cell masses are treated with heat at temperatures of from 105 to 160 ° C for 3 to 40 minutes, with the thermal energy being transmitted by contact, radiation or convection by means of a gaseous medium. 2. A process as claimed in claim 1, wherein the heat treatment is carried out for 5 to 20 minutes at a product temperature of 105 DEG to 140 DEG.