1、BRITISH STANDARD BS ISO 763:2003 Fruit and vegetable products Determination of ash insoluble in hydrochloric acid ICS 67.080.01 BS ISO 763:2003 This British Standard was published under the authority of the Standards Policy and S t r a t e g y C o m m i t t e e o n 1 December 2003 BSI 1 December 200
2、3 ISBN 0 580 42603 3 National foreword This British Standard reproduces verbatim ISO 763:2003 and implements it as the UK national standard. There has been no UK participation in the preparation of this document. Any enquiries on the text should be sent to the Head of Standards International Content
3、. Cross-references The British Standards which implement international publications referred to in this document may be found in the BSI Catalogue under the section entitled “International Standards Correspondence Index”, or by using the “Search” facility of the BSI Electronic Catalogue or of Britis
4、h Standards Online. This publication does not purport to include all the necessary provisions of a contract. Users are responsible for its correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations. Summary of pages This document comprises a fro
5、nt cover, an inside front cover, the ISO title page, pages ii and iii, a blank page, pages 1 to 4, an inside back cover and a back cover. The BSI copyright notice displayed in this document indicates when the document was last issued. Amendments issued since publication Amd. No. Date Comments Refere
6、nce number ISO 763:2003(E)INTERNATIONAL STANDARD ISO 763 Second edition 2003-12-01 Fruit and vegetable products Determination of ash insoluble in hydrochloric acid Produits drivs des fruits et lgumes Dtermination des cendres insolubles dans lacide chlorhydrique BSISO763:2003DPlcsid Fremia ihTs PDF f
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11、O cirypothg fofice saCe tsopale 65 eneG 1121-HC 02 av leT. 4 + 10 947 22 1 11 xaF0 947 22 14 + 9 74 E-mail coirypthgiso.o gr We bwww.is.o gro Pulbisdehi n Switlrez dnaii BSISO763:2003 iiiForeword ISO (the International Organization for Standardization) is a worldwide federation of national standards
12、 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 the right to be represented on that committee. International organiza
13、tions, 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. International Standards are drafted in accordance with the rules given in t
14、he ISO/IEC Directives, Part 2. The main task of technical committees is to prepare International Standards. 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
15、 the member bodies casting a vote. Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. ISO shall not be held responsible for identifying any or all such patent rights. ISO 763 was prepared by Technical Committee ISO/TC 34, Food produc
16、ts, Subcommittee SC 3, Fruit and vegetable products. This second edition cancels and replaces the first edition (ISO 763:1982), which has been technically revised. BSISO763:2003INTENRATIONAL TSANDADR IS:367 O3002(E)1Fruit and vegetable products Determination of ash insoluble in hydrochloric acid 1 S
17、cope This International Standard specifies a method for the determination of the hydrochloric-acid-insoluble ash yielded by fruit and vegetable products. The method serves for the determination of siliceous impurities, together with the silica endogenous to the plant. NOTE A method for the determina
18、tion of mineral impurities generally originating from the soil is specified in ISO 762 1) . 2 Principle A test portion is incinerated at approximately 525 C and the mineral matter insoluble in dilute hydrochloric acid is separated. 3 Reagents Use only reagents of recognized analytical grade, unless
19、otherwise specified, and distilled or demineralized water or water of equivalent purity. 3.1 Hydrochloric acid, 10 % (by mass) solution. 3.2 Silver nitrate, approximately 17 g/l solution. 4 Apparatus Usual laboratory apparatus and, in particular, the following. 4.1 Blender. 4.2 Muffle furnace, capab
20、le of being maintained at 525 C 25 C. 4.3 Boiling water bath. 4.4 Drying oven, capable of being maintained at 103 C 2 C. 4.5 Desiccator, containing an efficient desiccant. 4.6 Incineration dishes, made of quartz or platinum. 1) ISO 762, Fruit and vegetable products Determination of mineral impuritie
21、s content. BSISO763:20032 4.7 Filter paper, ashless. 4.8 Analytical balance, capable of weighing to the nearest 0,000 2 g. 5 Sampling It is important that the laboratory receive a sample which is truly representative and has not been damaged or changed during transport or storage. 6 Preparation of t
22、est sample Allow frozen or deep-frozen products to thaw in a closed vessel and add the liquid formed during this process to the product before mixing. Before taking the test portion, thoroughly mix the laboratory sample using, if necessary, the blender (4.1). 7 Procedure 7.1 Preparation of first dis
23、h Heat an empty dish (4.6) in the furnace (4.2) set at the incineration temperature. Allow it to cool in the desiccator (4.5) then weigh to the nearest 0,000 2 g. Repeat until a constant mass is achieved. 7.2 Test portion Weigh, to the nearest 0,01 g, in the previously prepared dish (7.1), 4 g to 25
24、 g of the test sample (Clause 6) according to the water content of the product. For liquid products, the test portion may be taken by volume (see 8.2). 7.3 Determination 7.3.1 Drying Place the dish and its contents in the boiling water bath (4.3) and evaporate the water present in the product. Dry i
25、n the oven (4.4) set at 103 C. This drying is not necessary for dry products. 7.3.2 Incineration After drying (if appropriate), carbonize and then completely incinerate the product in the furnace (4.2) set at 525 C; the ash may still be grey after incineration. Pre-incineration at a distinctly lower
26、 temperature before placing in the furnace is sometimes necessary for products with a high sugar content in order to avoid foaming and subsequent loss of foam. For that purpose, slowly heat the dried sample on the hot plate until carbonization of the most of the organic matter. It is recommended to
27、decrease the salt content of products containing more than 2 % of sodium chloride by the following method. Pre-incinerate the sample then wash the carbonaceous residue several times with small amounts of hot distilled water. 7.3.3 Treatment with hydrochloric acid Allow the sample to cool in the desi
28、ccator (4.5). After cooling, add 10 ml to 25 ml of the hydrochloric acid solution (3.1). Cover with a watch-glass and heat in the boiling water bath (4.3) for 15 min 2 min. BSISO763:2003 3Transfer the residue to the ashless filter paper (4.7) placed in a funnel. Rinse the dish with hot water and tra
29、nsfer the contents of the dish to the filter paper. Wash the filter paper and its contents until there is no trace of chloride ions in the liquid flowing from the funnel test with the silver nitrate solution (3.2) . 7.3.4 Preparation of the second dish Prepare a new dish (4.6) as specified in 7.1 or
30、 clean the first dish. Heat it in the muffle furnace (4.2) to the incineration temperature. Allow it to cool in the desiccator then weigh to the nearest 0,000 2 g. Repeat until a constant mass is achieved. 7.3.5 Drying and incineration Place the filter paper and residue in the dish. Dry in the oven
31、(4.4) set at 103 C, then incinerate in the muffle furnace (4.2), set at 525 C, for 30 min 2 min. Cool in the desiccator (4.5), then weigh to the nearest 0,000 2 g. Repeat until a constant mass is achieved. 8 Expression of results 8.1 Method of calculation The ash insoluble in hydrochloric acid, w, e
32、xpressed as a percentage by mass, is given by the formula 23 01 100 % mm w mm = where m 0is the mass, in grams, of the dish and test portion (7.2); m 1is the mass, in grams, of the empty dish (7.1); m 2is the mass, in grams, of the dish and acid-insoluble ash (7.3.5); m 3is the mass, in grams, of th
33、e second empty dish (7.3.4). Report the results to two decimal places. 8.2 Other method of expression For liquid products, it is possible to express the result in grams per 100 ml of product, by taking the test portion (7.2) by volume and by replacing the denominator (m 0 m 1 ) in the equation (see
34、8.1) by V, the volume of the test portion. 9 Repeatability The absolute difference between two independent single test results, obtained using the same method on identical test material in the same laboratory by the same operator using the same equipment within a short interval of time, will in not
35、more than 5 % of cases be greater than 0,01 g of ash insoluble in hydrochloric acid per 100 g of sample. BSISO763:20034 10 Test report The test report shall specify: a) all information necessary for the complete identification of the sample; b) the sampling method used, if known; c) the test method
36、used, with reference to this International Standard; d) all operating details not specified in this International Standard, or regarded as optional, together with details of any incidents which may have influenced the test result(s); e) the test result(s) obtained or, if the repeatability has been c
37、hecked, the final quoted result obtained. BSISO763:2003BS ISO 763:2003 BSI 389 Chiswick High Road London W4 4AL BSI British Standards Institution BSI is the independent national body responsible for preparing British Standards. It presents the UK view on standards in Europe and at the international
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