The ISO 5506 standard, developed by the International Standards Organization (ISO), specifies the method for determining the urease activity of products derived from soybeans. The method allows to detect insufficient cooking of these products.
Applicable to products with nitrogen urease activity of less than 1 mg per gram of product when taken, under specified conditions. For more active products, the method can be applied provided that the mass of the test section is reduced.
The method outlined in this document is based on the ability of soybean products to release ammonia nitrogen from a urea solution when they are not sufficiently cooked.
The floor test part should be mixed with the buffered urea solution. After the mixture is kept at 30 °C for 30 minutes, the liberated ammonia should be neutralized with excess hydrochloric acid solution and diluted with standard volumetric sodium hydroxide solution.
back titration should be included in the report.
All reagents will be of analytical quality and the water used will be distilled water or water of equivalent purity. A buffer solution should be prepared by dissolving 4,45 g of disodium hydrogen phosphate dehydrate (Na2HPO4.2H2O) and 3,40 g of potassium dihydrogen phosphate (KH2PO4) in water and making up to 1000 ml.
The test procedure is to transfer approximately 0,1 g of test sample, weighed to 0,2 mg precision, into a test tube. For samples with very high activity, the test fraction can be reduced to 0,05 g. It is recommended that the samples with an oil content of more than 10% be degreased beforehand by cold extraction.
Add 10 ml of buffered urea solution using a pipette. The tube is immediately closed and shaken vigorously. The test tube is placed in a water bath at 30 °C ± 0,5 °C and held there for 30 minutes [measured with a stopwatch]. Using a pipette, immediately add 10 ml of hydrochloric acid solution, quickly cool to 20 °C and quantitatively transfer the contents of the test tube to the titration flask, shake the test tube 5 twice.
Among the services provided by our organization within the framework of material testing services, there are also ISO 5506 standard tests.
To get an appointment, to get more detailed information or to request an evaluation, you can ask us to fill in our form and reach you.
EUROLABreporting and certification activities, United Accreditation Foundation (UAF), Turkish Accreditation Agency (TÜRKAK) ve Enterprise Accreditation Foundation (EAF) based on the accreditation provided by the accreditation body. The Enterprise Accreditation Foundation (EAF) accreditation body is also a signatory of the United Nations (UN GLOBAL COMPACT) organization.
