1、| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | BRITISH STANDARD BS EN 12145 : 1997 The Eu
2、ropean Standard EN 12145 : 1996 has the status of a British Standard ICS 67.160.20 NO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAW Fruit and vegetable juices Determination of total dry matter Gravimetric method with loss of mass on dryingBS EN 12145 : 1997 This British Standar
3、d, having been prepared under the direction of the Consumer Products and Services Sector Board, was published under the authority of the Standards Board and comes into effect on 15 May 1997 BSI 1997 The following BSI references relate to the work on this standard: Committee reference AW/21 Draft for
4、 comment 89/548090 DC ISBN 0 580 27059 9 Amendments issued since publication Amd. No. Date Text affected Committees responsible for this British Standard The preparation of this British Standard was entrusted to Technical Committee AW/21, Fruit and vegetable juices, upon which the following bodies w
5、ere represented: British Fruit Juice Importers Association British Retail Consortium British Soft Drinks Association Limited Campden and Chorleywood Food Research Association Laboratory of the Government Chemist Leatherhead Food Research Association Ministry of Agriculture, Fisheries and Food Royal
6、Society of ChemistryBS EN 12145 : 1997 BSI 1997 i Contents Page Committees responsible Inside front cover National foreword ii Foreword 2 Text of EN 12145 3ii BSI 1997 BS EN 12145 : 1997 National foreword This British Standard has been prepared by Technical Committee AW/21, and is the English langua
7、ge version of EN 12145 : 1996 Fruit and vegetable juices Determination of total dry matter Gravimetric method with loss of mass on drying, published by the European Committee for Standardization (CEN). EN 12145 was produced as a result of international discussions in which the United Kingdom took an
8、 active part. Cross-references Publication referred to Corresponding British Standard EN ISO 3696 : 1995 BS EN ISO 3696 : 1995 Specification for water for laboratory use ISO 5725 : 1986, to which informative reference is made in the text, has been superseded by ISO 5725-1 : 1994, ISO 5725-2 : 1994,
9、ISO 5725-3 : 1994, ISO 5725-4 : 1994 and ISO 5725-6 : 1994 which are identical with BS ISO 5725 Accuracy (trueness and precision) of measurement methods and results, BS ISO 5725-1 : 1994 General principles and definitions, BS ISO 5725-2 : 1994 Basic methods for the determination of repeatability and
10、 reproducibility of a standard measurement method, BS ISO 5725-3 : 1994 Intermediate measures of the precision of a standard measurement method, BS ISO 5725-4 : 1994 Basic methods for the determination of the trueness of a standard measurement method, and BS ISO 5725-6 : 1994 Use in practice of accu
11、racy values. 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, pages i and ii, the EN title page, pages 2 to 6, an inside back cover and a back cover.CEN European Committee for
12、Standardization Comite Europe en de Normalisation Europa isches Komitee fu r Normung Central Secretariat: rue de Stassart 36, B-1050 Brussels 1996 Copyright reserved to CEN members Ref. No. EN 12145 : 1996 E EUROPEAN STANDARD EN 12145 NORME EUROPE ENNE EUROPA ISCHE NORM September 1996 ICS 67.160.20
13、Descriptors: Food products, beverages, fruit and vegetable juices, chemical analysis, determination, dry matter, gravimetric analysis, weight losses English version Fruit and vegetable juices Determination of total dry matter Gravimetric method with loss of mass on drying Jus de fruits et de le gume
14、s De termination du re sidu sec total Me thode gravime trique par perte de poids a l a dessiccation Frucht- und Gemu sesa fte Bestimmung der gesamten Trockensubstanz Gravometrisches Verfahren mit Masseverlust beim Trocknen This European Standard was approved by CEN on 1996-05-09. CEN members are bou
15、nd to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such national standards may be obtained on application to the C
16、entral Secretariat or to any CEN member. This European Standard exists in three official versions (English, French, German). A version in any other language made by translation under the responsibility of a CEN member into its own language and notified to the Central Secretariat has the same status
17、as the official versions. CEN members are the national standards bodies of Austria, Belgium, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and United Kingdom.Page 2 EN 12145 : 1996 BSI 1997 Foreword This Euro
18、pean Standard has been prepared by Technical Committee CEN/TC 174, Fruit and vegetable juices Methods of analysis, of which the Secretariat is held by AFNOR. This European Standard shall be given the status of a national standard, either by publication of an identical text or by endorsement, at the
19、latest by March 1997, and conflicting national standards shall be withdrawn at the latest by March 1997. According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following countries are bound to implement this European Standard: Austria, Belgium, Denmark, Finlan
20、d, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and United Kingdom. Contents Page Foreword 2 1 Scope 3 2 Normative references 3 3 Principle 3 4 Reagents 3 5 Apparatus 3 6 Procedure 3 7 Calculation 4 8 Precision 4 9 Test repor
21、t 4 A (informative) Bibliography 5 B (informative) Statistical results of the interlaboratory test 5Page 3 EN 12145 : 1996 BSI 1997 1 Scope This European Standard specifies a gravimetric method for the determination of the total dry matter in fruit and vegetable juices and related products. 2 Normat
22、ive references This European Standard incorporates by dated or undated references, provisions from other publications. These normative references are cited at the appropriate places in the text and the publications are listed hereafter. For dated references, subsequent amendments to or revisions of
23、any of these publications apply to this European Standard only when incorporated in it by amendment or revision. For undated references the latest edition of the publication referred to applies. EN ISO 3696 : 1995 Water for analytical laboratory use Specification and test methods ISO 5725 : 1986 Pre
24、cision of test methods Determination of repeatability and reproducibility for a standard test method by inter-laboratory tests 3 Principle The determination of loss of mass on drying is carried out by mixing the sample thoroughly with kieselguhr or a similar material, pre-drying the mixture, and fin
25、ally drying for 2 h in a vacuum oven at 70 C 1 C and approximately 6,6 kPa (66 mbar) pressure. 4 Reagents Use only reagents of recognized analytical grade and water of at least grade 3 of EN ISO 3696 : 1995. 4.1 Kieselguhr, or a similar material. 5 Apparatus Usual laboratory apparatus and, in partic
26、ular, the following: 5.1 Drying equipment 5.1.1 Vacuum drying oven, with automatic temperature control, thermometer and vacuum manometer. This oven should be so constructed that the temperature variation across different parts of the interior does not exceed 2 C. 5.1.2 Drying oven, with ventilator,
27、automatic temperature control and thermometer. This oven should allow for speedy circulation and a sufficient exchange with the external air so that the initial moisture can be rapidly removed. 5.1.3 Water bath 5.2 Apparatus for drying the air, consisting of a column filled with freshly dried self-i
28、ndicating silica gel (or a similar material). This drying column should be placed in series with a gas-washing flask filled with concentrated sulfuric acid, and the whole assembly connected to the air inlet of the vacuum oven. As a safety precaution, empty gas-washing flasks should be connected both
29、 before and after the flask of concentrated sulfuric acid. 5.3 Vacuum pump, to evacuate and maintain a pressure of no more than 6,6 kPa (66 mbar) in the oven. 5.4 Corrosion-resistant metal dish, with a flat bottom and tightly closing lid, approximately 100 mm in diameter and at least 30 mm high. 5.5
30、 Glass rod, long enough to reach over the edge of the dish. 5.6 Desiccator, with freshly dried self-indicating silica gel (or equivalent). 5.7 Analytical balance, with an accuracy of 1 mg. 6 Procedure 6.1 Preparation of the test sample Normally products shall not be pretreated and their analysis by
31、this method shall be on a gravimetric basis, results being expressed as mass fraction in per cent. Mix cloudy samples well before analysis. 6.2 Test procedure 6.2.1 Pre-drying stage Weigh approximately 1,5 g of kieselguhr (4.1) into a metal dish (5.4). Place the dish and its lid separately into the
32、oven (5.1.2) and dry at 110 C 3 C for at least 4 h. Then cover the dish, place in the desiccator (5.6) and weigh accurately after cooling to room temperature (m 2 ). Weigh approximately 15 g of sample (correct to the nearest milligram) into the dish (m o ). Do this quickly to avoid any loss of moist
33、ure by evaporation. Mix the sample and the kieselguhr with the glass rod (5.5) and distribute the contents equally in the dish dilution with a little distilled water may make this easier. Rinse the glass rod with distilled water. The complete sample can now be taken to apparent dryness (pre-dried st
34、age) by one of the following procedures: heat the sample on a boiling water bath (5.1.3); place the sample in the oven (5.1.2) maintained at 70 C; place the sample in the vacuum oven (5.1.1) maintained at 70 C with the pressure reduced to about 41,3 kPa (413 mbar).Page 4 EN 12145 : 1996 BSI 1997 6.2
35、.2 Final drying stage Place the pre-dried sample (6.2.1) into the vacuum oven. Lower the pressure to approximately 6,6 kPa (66 mbar). Dry for 2 h at 70 C 1 C. Then close the vacuum tap and admit dry air until atmospheric pressure is reached. Close the dish with its lid and place immediately into the
36、 desiccator and allow to cool to room temperature. Weigh dish with lid and contents accurately (m 1 ). 7 Calculation Calculate the total solids, in per cent, from the following equation: T s =( m 1 2m 2 )3 100 m 0 where: T s is the total solids content, in per cent; m 0 is the original mass of sampl
37、e in grams (6.2.1); m 1 is the mass of the dish containing kieselguhr, lid and dry residue in grams (6.2.2); m 2 is the mass the dish containing kieselguhr and lid in grams (6.2.1). Take into account the dilution factor and the relation of the value to mass or volume. If a concentrated product has b
38、een diluted to single strength, report the relative density of the single strength sample. Report the total dry matter in per cent (m/m) to two decimal places. 8 Precision Details of the interlaboratory test on the precision of the method are summarized in annex B. The values derived from the interl
39、aboratory test may not be applicable to analyte concentration ranges and matrices other than given in annex B. 8.1 Repeatability The absolute difference between two single results found on identical test material by one operator using the same apparatus within the shortest feasible time interval wil
40、l exceed the repeatability limit r in not more than 5 % of the cases. The values are: apricot nectar : r = 0,13; tomato juice r = 0,10. 8.2 Reproducibility The absolute difference between two single test results on identical test material reported by two laboratories will exceed the reproducibility
41、limit R in not more than 5 % of the cases. The values are : apricot nectar : R = 0,56; tomato juice R = 0,32. 9 Test report The test report shall contain the following data: all information necessary for the identification of the sample (kind of sample, origin of sample, designation); a reference to
42、 this European Standard; the date and type of sampling procedure (if known); the date of receipt; the date of test; the test results and units in which they have been expressed; whether the repeatability of the method has been verified; any particular points observed in the course of the test; any o
43、perations not specified in the method or regarded as optional, which might have affected the results.Page 5 EN 12145 : 1996 BSI 1997 Table B.1. Sample A B Number of laboratories retained after eliminating outliers 10 11 Number of outliers (laboratories) 3 2 Number of accepted results 36 39 Mean valu
44、e ( ) (%) (m/m) x 2 14,3 5,9 Repeatability standard deviation (s r ) (%) (m/m) 0,0447 0,0367 Repeatability relative standard deviation (RSD r ) (%) 0,31 0,62 Repeatability limit (r) (%) (m/m) 0,13 0,10 Reproducibility standard deviation (s R ) (%) (m/m) 0,2003 0,1138 Reproducibility relative standar
45、d deviation (RSD R ) (%) 1,40 1,93 Reproducibility limit (R) (%) (m/m) 0,56 0,32 Annex A (informative) Bibliography 1 Appendix to the EEC Commission Directive No. 1979/82 of 19 July 1982 on analytical methods for estimation of total dry matter in tomato juice (Rule 4 Chapter 20 of the Common Customs
46、 Tariff. Publication No. 217/13 of 22.7.1982). 2 Determination of total dry matter. Method No. 61 (1991). In: The collected analyses of the International Federation of Fruit Juice Producers. Loose-leaf edition of 1996. Zug: Swiss Fruit Union. Annex B (informative) Statistical results of the interlab
47、oratory test In accordance with ISO 5725 : 1986, the following parameters have been defined in an interlaboratory test. (For literature pertaining to the method see annex A). The test was conduced by the International Federation of Fruit Producers (IFU), Paris, France. Year of interlaboratory test 1
48、990 Number of laboratories 13 Number of samples 2 Sample types: A apricot nectar; B tomato juice.6 blank BSI 1997 BS EN 12145 : 1997 List of references See national foreword.BSI 389 Chiswick High Road London W4 4AL | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
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