1、BRITISH STANDARD BS 4585-11: 1983 ISO 5567:1982 Methods of test for Spices and condiments Part 11: Determination of volatile organic sulphur compounds in dehydrated garlic UDC 633.82/.84:664.5:635.262:543.845BS4585-11:1983 This British Standard, having been prepared under the directionof the Food an
2、d Agriculture Standards Committee,was published underthe authority of the BoardofBSI and comes into effect on 28February1983 BSI 10-1999 The following BSI references relate to the work on this standard: Committee reference FAC/7 Draft for comment 81/52169 DC ISBN 0 580 13263 3 Committees responsible
3、 for this British Standard This British Standard was published under the direction of the Food and Agriculture Standards Committee FAC/-. Its preparation was entrusted to Technical Committee FAC/7 upon which the following bodies were represented: Association of Public Analysts British Essence Manufa
4、cturers Association British Food Manufacturing Industries Research Association Co-operative Union Department of Industry (Laboratory of the Government Chemist) Food Manufacturers Federation Incorporated General Produce Brokers Association of London Ministry of Agriculture, Fisheries and Food Oversea
5、s Development Administration (Tropical Products Institute) Amendments issued since publication Amd. No. Date of issue CommentsBS4585-11:1983 BSI 10-1999 i Contents Page Committees responsible Inside front cover National foreword ii 1 Scope and field of application 1 2 Principle 1 3 Reagents 1 4 Appa
6、ratus 1 5 Procedure 1 6 Expression of results 2 7 Test report 2 Figure Allyl sulphide distillation apparatus (recommended) 3BS4585-11:1983 ii BSI 10-1999 National foreword This Part of BS4585, which has been prepared under the direction of the Food and Agriculture Standards Committee, is identical w
7、ith ISO 5567:1982 “Dehydrated garlic Determination of volatile organic sulphur compounds”. The International Standard was prepared by Subcommittee 7, Spices and condiments, of Technical Committee 34, Agricultural food products, of the International Organization for Standardization (ISO). Terminology
8、 and conventions. The text of the International Standard has been approved as suitable for publication as a British Standard without deviation. Some terminology and certain conventions are not identical with those used in British Standards; attention is drawn especially to the following. The comma h
9、as been used as a decimal marker. In British Standards it is current practice to use a full point on the baseline as the decimal marker. Wherever the words “International Standard” appear, referring to this standard, they should be read as “British Standard”. A British Standard does not purport to i
10、nclude all the necessary provisions of a contract. Users of British Standards are responsible for their correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations. Summary of pages This document comprises a front cover, an inside front cover, pa
11、ges i and ii, pages 1 to 3 and a back cover. This standard has been updated (see copyright date) and may have had amendments incorporated. This will be indicated in the amendment table on the inside front cover.BS4585-11:1983 BSI 10-1999 1 1 Scope and field of application This International Standard
12、 specifies a method for the determination of volatile organic sulphur compounds in dehydrated garlic. 2 Principle After maceration of a test portion in aqueous medium, addition of ethanol, distillation of the volatile organic sulphur compounds, and argentimetric titration of the distillate in nitric
13、 acid medium. 3 Reagents The reagents shall be of recognized analytical purity and the water used shall be distilled water or water of at least equivalent purity. 3.1 Ethanol, 95 % (V/V). 3.2 Liquid paraffin 3.3 Ammonium hydroxide, 10 % solution. 3.4 Silver nitrate, 0,1 mol/l solution. 3.5 Nitric ac
14、id, 20. 1,40 g/ml. 3.6 Nitric acid, 10 % (V/V) solution. 3.7 Iron ammonium alum, cold saturated solution. 3.8 Ammonium thiocyanate, standard volumetric solution, c(NH 4 SCN) = 0,1 mol/l. 4 Apparatus NOTEDuring the analysis, avoid all contact with copper or rubber, especially in the distillation appa
15、ratus. The apparatus should have ground glass joints. Usual laboratory apparatus, and in particular 4.1 Distillation apparatus (see the Figure), consisting of a250ml flask with a ground-neck which can be fitted with a stopper, and a straight condenser. 4.2 Conical flask, of capacity 250 ml with a gr
16、ound-neck which can be fitted with a reflux condenser. 4.3 One-mark pipette, of capacity 20 ml. 4.4 Burette with tap, of capacity 25 ml, accurate to0,05 ml. 4.5 Thermostatically controlled bath, capable of being controlled at37 1 C. 4.6 Balance 4.7 Fritted glass filter, of porosity4to164m, and a fil
17、ter flask. 4.8 Vacuum pump 5 Procedure 5.1 Preparation of the test sample Homogenize the laboratory sample of dehydrated garlic and, if necessary, reduce it to fine particles. 5.2 Test portion Weigh, to the nearest0,01g, about10g of the test sample. 5.3 Determination 5.3.1 Maceration Introduce the t
18、est portion into the flask of the distillation apparatus (4.1), add100ml of water at40 C, and allow to macerate for2h in the thermostatically controlled bath (4.5) at37 1 C, keeping the flask closed by means of a ground stopper. 5.3.2 Distillation Add20ml of the ethanol (3.1) and2ml of the liquid pa
19、raffin (3.2) to avoiding frothing. Connect the flask quickly to the condenser, with the tip of the latter dipping into the conical flask (4.2) containing approximately10ml of the ammonium hydroxide solution (3.3). Ensure that the tip of the condenser is below the surface of the ammonium hydroxide so
20、lution. Regulate the heating in such a way as to avoid entraining any froth that might be formed despite the presence of the liquid paraffin. Heat the flask (see 4.1) so as to a obtain a brisk rate of distillation and continue the distillation until about60ml of distillate has been collected. Rinse
21、the condenser with water, collecting the rinsings in the conical flask. 5.3.3 Titration Neutralize the ammoniacal distillate in the flask(4.2), adjusting the pH to7 0,1by addition of the nitric acid solution (3.6). By means of a pipette (4.3), add20ml of the silver nitrate solution (3.4) and boil un
22、der reflux for1h. Cool the flask and filter the distillate on the fritted glass filter (4.7) placed on the filter flask, operating under suction applied by means of the vacuum pump (4.8). Wash the precipitate four times with hot water and collect the filtrate and washings quantitatively. Add about5m
23、l of the nitric acid (3.5), a few drops of the iron ammonium alum solution (3.7) and titrate with the ammonium thiocyanate solution (3.8) until a persistent pink coloration is obtained.BS4585-11:1983 2 BSI 10-1999 5.4 Number of determinations Carry out two determinations on the same prepared sample.
24、 6 Expression of results 6.1 Method of calculation and formula The volatile organic sulphur compounds content, expressed as allyl sulphide as a percentage by mass, is equal to where Take as the result the arithmetic mean of the values obtained in the two determinations, provided that the requirement
25、s for repeatability (see 6.2) are satisfied. Otherwise, repeat the analysis. 6.2 Repeatability The difference between the results of two determinations carried out simultaneously or in rapid succession by the same analyst shall not exceed 5 % of the mean. 7 Test report The test report shall show the
26、 method used and the results obtained. It shall also mention any operating conditions not specified in this International Standard, or regarded as optional, as well as any incidents likely to have influenced the results. The test report shall include all the information necessary for the complete id
27、entification of the sample. m is the mass, in grams, of the test portion; V is the volume, in millilitres, of the ammonium thiocyanate solution used. 0,005 720V () 100 m - BS4585-11:1983 BSI 10-1999 3 Figure Allyl sulphide distillation apparatus (recommended)BS 4585-11: 1983 ISO 5567:1982 BSI 389 Ch
28、iswick High Road London W4 4AL BSIBritishStandardsInstitution BSI is the independent national body responsible for preparing BritishStandards. It presents the UK view on standards in Europe and at the international level. It is incorporated by Royal Charter. Revisions BritishStandards are updated by
29、 amendment or revision. Users of BritishStandards should make sure that they possess the latest amendments or editions. It is the constant aim of BSI to improve the quality of our products and services. We would be grateful if anyone finding an inaccuracy or ambiguity while using this BritishStandar
30、d would inform the Secretary of the technical committee responsible, the identity of which can be found on the inside front cover. Tel:02089969000. Fax:02089967400. BSI offers members an individual updating service called PLUS which ensures that subscribers automatically receive the latest editions
31、of standards. Buying standards Orders for all BSI, international and foreign standards publications should be addressed to Customer Services. Tel:02089969001. Fax:02089967001. In response to orders for international standards, it is BSI policy to supply the BSI implementation of those that have been
32、 published as BritishStandards, unless otherwise requested. Information on standards BSI provides a wide range of information on national, European and international standards through its Library and its Technical Help to Exporters Service. Various BSI electronic information services are also availa
33、ble which give details on all its products and services. Contact the Information Centre. Tel:02089967111. Fax:02089967048. Subscribing members of BSI are kept up to date with standards developments and receive substantial discounts on the purchase price of standards. For details of these and other b
34、enefits contact Membership Administration. Tel:02089967002. Fax:02089967001. Copyright Copyright subsists in all BSI publications. BSI also holds the copyright, in the UK, of the publications of the international standardization bodies. Except as permitted under the Copyright, Designs and Patents Ac
35、t 1988 no extract may be reproduced, stored in a retrieval system or transmitted in any form or by any means electronic, photocopying, recording or otherwise without prior written permission from BSI. This does not preclude the free use, in the course of implementing the standard, of necessary detai
36、ls such as symbols, and size, type or grade designations. If these details are to be used for any other purpose than implementation then the prior written permission of BSI must be obtained. If permission is granted, the terms may include royalty payments or a licensing agreement. Details and advice can be obtained from the Copyright Manager. Tel:02089967070.
