ISO INTERNATIONAL STANDARD 2448 Second edition 1998-08-01 Fruit and vegetable products - Determination of ethanol content Produits dérivés des fruits et leégumes Determination de la teneur enéthanol ISO Reference number ISO 2448:1998(E) ISO2448:1998(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 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 voting. Publication as an International Standard requires approval by at least 75 % of the member bodies casting a vote. International Standard ISO 2448 was prepared by Technical Commitee ISO/TC 34, Agricultural food products Subcommittee SC 3, Fruit and vegetable products. This second edition cancels and replaces the first edition (IsO 2448:1973), which has been technically revised. Annex A forms an integral part of this International Standard. @ISO1998 International Organization for Standardization Case postale 56·CH-1211Geneve 20·Switzerland Internet iso@iso.ch Printed in Switzerland ii INTERNATIONAL STANDARD@ISO ISO 2448:1998(E) Fruit and vegetable products Determination of ethanol content 1 Scope This International Standard specifies a method for the chemical determination of ethanol in fruit and vegetable products. The method is not applicable to products containing more than 5 % (m/m) of ethanol. In the case of products containing essential oils, it is necessary to remove the latter (see annex A). 2 Definition 2.1 ethanol content mass of the substances determined by the method specified in this International Standard, expressed as a 3 Principle Separation of the ethanol by distillation, followed by oxidation by potassium dichromate in a sulfuric acid medium Determination of the excess dichromate by ammonium iron(Il) sulfate in the presence of iron(IlI)-1,10- phenanthroline as indicator. 4 Reagents Use only reagents of recognized analytical grade, unless otherwise specified, and distilled or demineralized water or water of equivalent purity. 4.1 Sulfuric acid (H2SO4), P20 = 1,84 g/ml. 4.2 Dilute sulfuric acid, P20 = 1,49 g/ml, containing 500 ml of sulfuric acid (4.1) per litre water. 4.4 Potassium dichromate solution, containing 42,572 g of K2Cr2O7 per litre. 1 ml of this solution is equivalent to 0,01 g of ethanol. 4.5 Potassium permanganate solution, containing 1,372 g of KMnO4 per litre. 10 ml of this solution is equivalent to 1 ml of ammonium iron(Il) sulfate solution (4.6). 4.6Ammonium iron(II) sulfate solution [(NH4)2Fe(SO4)].