ISO INTERNATIONAL STANDARD 3496 Second edition 1994-09-01 Meat and meat products Determination of hydroxyproline content Viandes et produits a base de viande - Détermination de la teneur en hydroxyproline ISO Referencenumber ISO 3496:1994(E) IS0 3496:1994(E) Foreword IsO (the International Organization for Standardization) is a worldwide 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, governmental 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 voting. Publication as an International Standard requires approvalby at least75 %of the member bodies casting avote. International Standard ISO 3496 was prepared by Technical Committee ISO/TC 34, Agricultural food products, Subcommittee SC 6, Meat and meatproducts. This second edition cancels and replaces the first edition (IS0 3496:1978), which has been technically revised. AnnexAof thisInternationalStandardisforinformationonly ISO1994 All rights reserved. Unless otherwise specified, no part of this publication may be reproduced microfilm, without permission in writing from the publisher. International Organization for Standardization CasePostale56·CH-1211Geneve20·Switzerland Printed in Switzerland INTERNATIONALSTANDARDISO ISO3496:1994(E) Meat and meat products Determination of hydroxyproline content 1 Scope trated sulfuric acid (p2o = 1,84 g/ml). Cool to room temperature and make up to the mark with water. This International Standard specifies a method for the determination of the hydroxyproline content of all 4.2 Buffer solution, pH = 6,8, consisting of: kinds of meat and meat products, including poultry 26,0 g of citric acid monohydrate (CsHgO,.H2O) It is applicable to meat and meat products containing less than 0,5 % (m/m) hydroxyproline. 14,0 g of sodium hydroxide; 78,0 g of anhydrous sodium acetate 2Definition [Na(CH,CO2]. For the purposes of this International Standard, the Dissolve the reagents in 500 ml of water and transfer following definition applies. quantitatively into a 1 litre one-mark volumetric flask. Add 250 ml of propan-1-ol and make up to the mark 2.1 hydroxyproline content of meat and meat withwater products: Content of hydroxyproline determined ac- cording to the procedure specified in this International When stored at 4 °C in the dark, this solution is stable Standard. for several weeks. The content is expressed as a percentage by mass. 4.3 Chloramine-T reagent Dissolve 1,41 gof sodium N-chloro-p-toluene- 3Principle sulfonamide trihydrate (chloramine-T) in 100 ml of the buffer solution (4.2). Hydrolysis of a test portion in sulfuric acid at 105 C Filtration and dilution of the hydrolysate. Oxidation of Prepare this solution immediately before use. the hydroxyproline by chloramine-T, followed by the formation of a red compound with p-dimethyl- 4.4 Colour reagent aminobenzaldehyde. Photometric measurement at a wavelength of 558 nm. Dissolve 10,0 g of p-dimethylaminobenzaldehyde in 35 ml of perchloric acid solution [60 % (m/m)] and Reagents then slowly add 65 ml of propan-2-ol. 4 Prepare this solution on the day of use. Useonly reagents of recognized analytical qualityand distilled or demineralized water or water of equivalent If purification of p-dimethylaminobenzaldehyde is purity necessary (see note 3 in 8.4), proceed as follows. Prepareasaturatedsolutionof p-dimethyl- 4.1 Sulfuric acid solution, c(H,SO4) ~ 3 mol/l. aminobenzaldehyde in hot 70 % (V/M) ethanol. Cool, first at room temperature and finaily in a refrigerator. Add 750 ml of water to a 2 litre one-mark volumetric After about