ISO INTERNATIONAL STANDARD 935 First edition 1988-01-15 INTERNATIONAL ORGANIZATION FOR STANDARDIZATION ORGANISATION INTERNATIONALE DE NORMALISATION MEXKAYHAPOAHAAOPIAHM3ALMAO CTAHAAPTM3ALMM Animal and vegetable fats and oils -- Determination of titre Corps gras d'origines animale et vegetale - Determination du titre ISO 935:1988 (E) No reproduction or networking permitted without license from IHS Foreword Iso (the International Organization for Standardization) is a worldwide federation of national standards bodies (iso member bodies). The work of preparing International Standards is normally carried out through Iso technical committees. Each member body interested in a subject for which a technical committee has been established has the right to be represented on that committee. International organizations, govern- mental and non-governmental, in liaison with Iso, also take part in the work. Draft International Standards adopted by the technical committees are circulated to the member bodies for approval before their acceptance as International Standards by the ISo Council. They are approved in accordance with ISO procedures requiring at least 75 % approval by the member bodies voting. International Standard ISO 935 was prepared by Technical Committee ISO/TC 34, Agricultural food products. It cancels and replaces ISo Recommendation R 935 : 1969, of which it constitutes a technical revision. Users should note that all International Standards undergo revision from time to time latestedition,unlessotherwisestated. @ International Organization for Standardization, 1988 Printed in Switzerland n for Standardization d by IHS Not for Resale ISO935:1988 (E) INTERNATIONAL STANDARD Animal and vegetable fats and oils - Determination of titre 1 Scopeandfieldofapplication heating to not more than 130 C.Foaming may occur at higher temperatures. This International Standard specifies a method for the prepara- tion of the water-insoluble fatty acids of animal and vegetable 5.2 Sulfuric acid, solution prepared by carefully adding fats and oils and the determination of their solidification 1volume of concentrated sulfuric acid (o = 1,84 g/ml)to temperature, called conventionally the titre of the fat or oil. 4 volumes of water, while strring. The method is not applicable to fats and oils the titre of which is below 30 °c. 5.3 Sodium chloride, 100 g/l solution. 5.4 Sodium sulfate, anhydrous. 2 References 5.5 Methyl orange, 5 g/l indicator solution. ISo 661, Animal and vegetable fats and oils- Preparation of test sample. Iso5555,Animal and vegetablefatsand oils-Sampling. 6 Apparatus 3Definition Usual laboratory apparatus and in particular For the purposes of this International Standard, the following 6.1Flat-bottomedflask or beaker,of1litrecapacity, definition applies. made of borosilicate glass. titre: Constant temperature observed when there is a tem- porary halt in the fall in temperature or, if there is an increase in 6.2Electrichotplate,capableofbeingcontrolledatapproxi- temperature, the maximum temperature reached during the mately 130 and at 140 ± 10 oC, preferably having a magnetic cooling, with continuous stirring, of liquid fatty acids. stirrer. 6.3Separatingfunnel,of500mlcapacity 4Principle Saponification of a test portion with potassium hydroxide solu- 6.4Cooling apparatus, fitted with an apparatus suitable for continuous stirring (seethefigure). tion. Washing of the separated insoluble fatty acids with hot sodium chloride solution, drying and filtering. 6.4.1 Wide-necked jar, of height 130 mm and external diameter 100 mm. Melting of the prepared fatty acids, cooling them, with con- tinuous stirring, and observation "of the solidification 6.4.2 Test tube, 100 mm × 25 mm, fitted with a stirrer that temperature as shown by a halt in the fall of temperature, can be operated continuously and move through a vertical possiblyaccompaniedbyatemporaryriseintemperature. No reproduction or networking permitted without license from IHS Not for Res