ISO 729 INTERNATIONAL STANDARD Second edition 1988-11-01 INTERNATIONAL ORGANIZATION FOR STANDARDIZATION ORGANISATION INTERNATIONALE DE NORMALISATION MEXKAYHAPOAHAN OPrAHM3ALMA O CTAHAAPTW3ALWM Oilseeds - Determination of acidity of oils Graines oléagineuses - Détermination de I'acidite de I'huile Referencenumber ISO 729: 1988 (E) working permitted without license from IHS Not for Resale ISO 729 : 1988 (E) 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. ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization 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 729 was prepared by Technical Committee ISO/TC 34, Agricultural food products. This second edition cancels and replaces the first edition (iS0 729 : 1985), of which it constitutes a minor revision. International Organization for Standardization, 1988 Printed in Switzerland itted without license from IHS Not for Resale ISO 729 : 1988 (E) INTERNATIONAL STANDARD Oilseeds - Determination of acidity of oils Scope 3.2 acidity: Conventional expression of the percentage of 1 free fatty acids. This International Standard specifies a method for the deter. According to the nature of the fat or oil, acidity may be mination of the acidity of oils in oilseeds. The acidity is ex- expressed as shown in table 1. pressed, by preference, as an acid value or alternatively as conventionally calculated acidity. Table 1 NOTE 1 -- This International Standard has been developed in align ment with Is0 6601). Molar mass Nature of fat or oil Expressed as (g / mol) The acidity may be determined on the oil from the product as Copra oil, palm kernel oil received (pure seeds and impurities), or, if required, on the pure and similar oils with high seeds and possibly on the impurities. 200 lauric acid content Lauric acid The method is not applicable to cotton seeds with adherent All other fats and oils Oleic acid 282 cotton linters, or to oil palm or olive fruits. NOTE 2 -- Owing to the particularly poor results obtained during interlaboratory tests on seeds and fruits with high lauric acid content definition, this is, by convention, the acidity expressed as oleic (copra and palm kernel), the application of this method to these acid. oilseeds is at present problematic. 4Principle Normative references Dissolution in a mixture of diethyl ether and ethanol of the oil The following standards contain provisions which, through extracted for the determination of the"oil content" of the seeds, and then titration of the free fatty acids present using an reference in this text, constitute provisions of this International ethanolic potassium hydroxide solution. Standard. At the time of publication, the editions indicated were valid. All standards are subject to revision, and parties to agreements based on this International Standard are encouraged Reagents to investigate the possibility of applying the most recent editions of the standards listed below. Members of IEC and ISO All the reagents shall be of recognized analytical grade and the maintain registers of currently valid International Standards. water used shall be distilled water or water of equivalent purity IsO 542 : 1980, Oilseeds - Sampling. 5.1 Diethyl ether