5498 (ISO International Standard Agricultural food products -- Determination of crude fibre content - General method Produits agricoles alimentaires -- Détermination de I'indice d'insoluble dit 《cellulosique》 - -Méthodegénérale First edition - 1981-04-15 UDC 664 : 543.868 Ref. No. ISO 5498-1981 (E) SO 5498-1981 Descriptors : agricultural products, tests, determination, indexes (ratios), insoluble matter, extraction analysis. Price based on 8 pages Copyright International Organization for Standardization d without license from IHS Not for Resale Foreword national standards institutes (iSO member bodies). The work of developing Inter- national Standards is carried out through ISO technical committees. Every member body interested in a subject for which a technical committee has been set up has the right to be represented on that committee. International organizations, governmental 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. International Standard ISO 5498 was developed by Technical Committee ISO/TC 34, Agricultural food products, and was circulated to the member bodies in September 1979. It has been approved by the member bodies of the following countries : Australia France Netherlands Germany, F.R. Poland Austria Brazil Hungary Portugal Bulgaria India Romania Canada Israel South Africa, Rep. of Chile Kenya Spain Cyprus Korea, Rep. of Thailand Czechoslovakia Libyan Arab Jamahiriya Turkey Egypt, Arab Rep. of Malaysia United Kingdom Ethiopia Mexico Yugoslavia The member body of the following country expressed disapproval of the document on technical grounds : USA International Organization for Standardization, 1981 Printed in Switzerland n or networking permited without license from IHS Not for Resale ISO 5498-1981 (E) INTERNATIONAL STANDARD Agricultural food products - Determination of crude fibre content - General method O Introduction The crude fibre content is expressed as a percentage by mass referred either to the product as received or to the dry matter There are numerous methods for the determination of the content of the product. crude fibre content of agricultural food products and, for a - In French, the term "indice d'insoluble dit cellulosique" has given method, numerous variants are used according to the NOTE products analysed, or, for the same product, from laboratory to brute". laboratory. This International Standard therefore fulfils a need for har- Principle 5 monization. It specifies a method of general application based on the Weende method, which is the most commonly used, After any necessary grinding and defatting, boiling with and basically involves acid treatment followed by alkaline treat- suiphuric acid solution of standard concentration, and separa- ment. tion and washing of the insoluble residue. Studies carried out have demonstrated the need to specify Boiling this residue with sodium hydroxide solution of standard precisely the conditions for the acid and alkaline treatments and concentration, then separation, washing, drying and weighing to describe the various procedures used for separating the in- of the insolubie residue, and determination of the loss in mass soluble matter. These procedures are described in annex B. on incineration. Scope 1 Reagents and materials This International Standard specifies a conventional method for All reagents shall be of recognized analytical quality and the the determination of the crude fibre content of agricultural food water used shall be distilled water or water of at least equivalent products. purity. 6.1 Sulphuric acid, standard volumetric solution, 2 Field of application c(1/2 H2SO4) = 0,255 ± 0,005 mol/I (corresponding to 12,5 g of sulphuric acid per litre of solution). The method is intended for general application; however, it may be necessary, i