OSI) 5520 International Standard INTERNATIONAL ORGANIZATION FOR STANDARDIZATION MEXKAYHAPOAHAA OPFAHU3AUMA NO CTAHAAPTW3AWWORGANISATION INTE RNATIONALE DE NORMALISATION Fruits, vegetables and derived products - Determination of alkalinity of total ash and of water-soluble ash Fruits, legumes et produits derivés -- Détermination de I'alcalinité des cendres totales et des cendres solubles dans I'eau First edition - 1981-08-15 UDC 634/635 : 543.82 Ref. No. ISO 5520-1981 (E) SO 5520-1981 (E) Descriptors : fruits, vegetables, fruit and vegetable products, chemical analysis, determination, alkalinity, ashes. Price based on 3 pages ttedwithout license fromIHS Not forResale Foreword Iso (the International Organization for Standardization) is a worldwide federation of 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 5520 was developed by Technical Committee ISO/TC 34, Agricultural food products, and was circulated to the member bodies in August 1979. It has been approved by the member bodies of the following countries : France Australia Netherlands Germany, F. R. Austria Peru Brazil Hungary Poland India Portugal Bulgaria Canada Indonesia Romania Israel South Africa, Rep. of Chile Kenya Cyprus Spain Czechoslovakia Korea, Rep. of Thailand Egypt, Arab Rep. of Malaysia USSR Mexico Yugoslavia Ethiopia The member body of the following country expressed disapproval of the document on technical grounds New Zealand @ International Organization for Standardization, 1981 Printed in Switzerland ted without license from IHS Not for Resale INTERNATIONAL STANDARD ISO 5520-1981 (E) Fruits, vegetables and derived products - Determination of alkalinity of total ash and of water-soluble ash 1 Scope and field of application Reagents This International Standard specifies a method for the deter- All reagents shall be of recognized analytical quality. The water mination of the alkalinity of the total ash and a method for the used shall be distilled water or water of at least equivalent purity, freshly boiled. determination of the alkalinity of the water-soluble ash from fruits, vegetables and derived products. 4.1 Sulphuric acid, 0,1 N standard volumetric solution. 2 Definitions 4.2 Sodium hydroxide, 0,1 N standard volumetric solution (for total ash). 2.1 alkalinity of total ash : The quantity of acid, expressed in milliequivalents, required to neutralize the ash obtained from 4.3 Indicator. 100 g of sample, under the conditions specified in this Inter- national Standard. Add 4 ml of 10 g/l methylene blue solution to 100 mil of 1 g/l methyi orange solution.1) The alkalinity of the total ash may also be expressed as the alkalinity index (2.2). Apparatus 2.2 alkalinity index : The number of millilitres of 1 N acid solution required to neutralize 1 g of the ash obtained from the Usual laboratory apparatus, and in particular : sample, under the conditions specified in this International Standard. 5.1 Dishes, of vitreous silica or metal inert under the con- ditions of the test. 2.3 alkalinity of water-soluble ash : The quantity of acid, expressed in milliequivalents, required to neutralize the 5.2 Electric muffle furnace, capable of being controlled at aqueous extract of the ash obtained from 100 g of sample, 525 ± 25 °C. under the conditions specified in this International Standard. 5.3 Desiccator, containing an efficient desiccant. 3Principle Burettes. 5.4 3.1 Total ash 5.5 Analytical balance. Incinerat