BS EN ISO 3657:2020 pdf free.Animal and vegetable fats and oils -Determination of saponification value.
This document specifies a method for the determination of the saponification value of animal andvegetable fats and oils.The saponification value is a measure of the free and esterified acids present infats and fatty acids.
The method is applicable to refined and crude vegetable and animal fats.
lf mineral acids are present, the results given by this method are not interpretable unless the mineralacids are determined separately.
The saponification value can also be calculated from fatty acid data obtained by gas chromatographyanalysis as given in Annex B.For this calculation, it is necessary to be sure that the sample does notcontain major impurities or is thermally degraded.
The following documents are referred to in the text in such a way that some or all of their contentconstitutes requirements of this document. For dated references, only the edition cited applies. Forundated references, the latest edition of the referenced document (including any amendments) applies.
The test sample is saponified by boiling under reflux with an excess of ethanolic potassium hydroxide,followed by titration of the excess potassium hydroxide with standard volumetric hydrochloricacid solution.
The test samples are carefully mixed and filtered if visible impurities are present. If filtration isnecessary, this shall be mentioned in the test report.
Weigh, to the nearest 5 mg, approximately 2 g of the test sample (see Clause 8) into a conical flask(6.1).The test portion of 2 g has been determined on the basis of saponification values of 170 to 200.For othersaponification values, the mass should be altered accordingly so that approximately half the ethanolicpotassium hydroxide solution is neutralized. Recommendations for the mass of the test portion aregiven in Table 1.
Using a pipette (6.5), add to the test portion 25,0 ml of the ethanolic potassium hydroxidesolution(5.2) and some boiling aids (5.6).Connect the reflux condenser (6.2) to the flask, place the flaskon the heating device (6.3) and boil gently, shaking from time to time, for 60 min or for 2 h in the case ofoils and fats having a high melting point and which are difficult to saponify.BS EN ISO 3657 pdf download.