1、BRITISH STANDARD BS EN 1131:1995 Method for Determination of therelative density of fruit and vegetable juices The European Standard EN1131:1994 has the status of a British Standard UDC 663.81/.82:620.1:531.756BS EN1131:1995 This British Standard, having been prepared under the directionof the Consu
2、mer Products and Services Sector Board(W/-), was published underthe authority of the Standards Board and comes intoeffect on 15 January1995 BSI 12-1999 The following BSI references relate to the work on this standard: Committee reference AW/21 Draft for comment 89/54815 DC ISBN 0 580 23150 X Coopera
3、ting organizations The European Committee for Standardization(CEN), under whose supervision this European Standard was prepared, comprises the national standards organizations of the following countries: Austria Oesterreichisches Normungsinstitut Belgium Institut belge de normalisation Denmark Dansk
4、 Standard Finland Suomen Standardisoimisliito, r.y. France Association franaise de normalisation Germany Deutsches Institut fr Normung e.V. Greece Hellenic Organization for Standardization Iceland Technological Institute of Iceland Ireland National Standards Authority of Ireland Italy Ente Nazionale
5、 Italiano di Unificazione Luxembourg Inspection du Travail et des Mines Netherlands Nederlands Normalisatie-instituut Norway Norges Standardiseringsforbund Portugal Instituto Portugus da Qualidade Spain Asociacin Espaola de Normalizacin y Certificacin Sweden Standardiseringskommissionen i Sverige Sw
6、itzerland Association suisse de normalisation United Kingdom British Standards Institution Amendments issued since publication Amd. No. Date CommentsBSEN1131:1995 BSI 12-1999 i Contents Page Cooperating organizations Inside front cover National foreword ii Foreword 2 Text of EN1131 3 National annex
7、NA (informative) Committees responsible Inside back cover National annex NB (informative) Cross-references Inside back coverBS EN1131:1995 ii BSI 12-1999 National foreword This British Standard has been prepared by Technical Committee AW/21, Fruit and vegetable juices, and is the English language ve
8、rsion of EN1131:1994 Fruit and vegetable juices Determination of relative density, published by the European Committee for Standardization(CEN). EN1131 was produced as a result of international discussions in which the United Kingdom took an active part. A British Standard does not purport to includ
9、e 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, pagesi
10、andii, theEN title page, pages2 to6, an inside back cover 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.EUROPEAN STANDARD NORME EUROPENNE EUROPISCHE NORM EN1131 O
11、ctober1994 UDC 663.81/.82:620.1:531.756 Descriptors: Food products, beverages, fruit and vegetable juices, chemical analysis, measurements, density(mass volume) English version Fruit and vegetable juices Determination of the relative density Jus de fruits et de lgumes Dtermination de la densit relat
12、ive Frucht- und Gemsesfte Bestimmung der relativen Dichte This European Standard was approved by CEN on1994-09-29. CEN members are bound 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
13、alteration. Up-to-date lists and bibliographical references concerning such national standards may be obtained on application to the Central 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 tr
14、anslation under the responsibility of a CEN member into its own language and notified to the Central Secretariat has the same status as the official versions. CEN members are the national standards bodies of Austria, Belgium, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxemb
15、ourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and United Kingdom. CEN European Committee for Standardization Comit Europen de Normalisation Europisches Komitee fr Normung Central Secretariat: rue de Stassart 36, B-1050 Brussels 1994 Copyright reserved to CEN members Ref. No. EN1131
16、:1994 EEN1131:1994 BSI 12-1999 2 Foreword This European Standard has been prepared by the Technical Committee CEN/TC174, Fruit and vegetable juices Methods of analysis, the secretariat of which is held by AFNOR. This European Standard shall be given the status of a National Standard, either by publi
17、cation of an identical text or by endorsement, at the latest by April1995, and conflicting national standards shall be withdrawn at the latest by April1995. Annexes designated “informative” are given only for information. In this standard Annex A and Annex B are informative. In accordance with the C
18、EN/CENELEC Internal Regulations, the following countries are bound to implement this European Standard: Austria, Belgium, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and United Kingdom. Contents Page Forewo
19、rd 2 1 Scope 3 2 Normative references 3 3 Definition 3 4 Principle 3 5 Reagents 3 6 Apparatus 3 7 Procedure 3 8 Calculation 4 9 Precision 4 10 Test report 4 Annex A (informative) Bibliography 5 Annex B (informative) Statistical results of theinterlaboratory test 5 Table B.1 5EN1131:1994 BSI 12-1999
20、3 1 Scope This European Standard specifies a method for the determination of the relative density d 20 C/20 Cof fruit and vegetable juices and related products. 2 Normative references This European Standard incorporates by dated or undated reference, provisions from other publications. These normati
21、ve 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 any of these publications apply to this European Standard only when incorporated in it by amendment or revision. For undated referen
22、ces the latest edition of the publication referred to applies. ISO5725:1986, Precision of test methods Determination of repeatability and reproducibility for a standard test method by inter-laboratory tests. ISO3696:1987, Water for analytical laboratory use Specification and test methods. 3 Definiti
23、on For the purposes of this standard, the following definition applies: 3.1 relative density, d 20 C/20 C the mass of a known volume of the test sample at20 C divided by the mass of an equal volume of air-free water at20C(pure number without units) 4 Principle The relative density is determined usin
24、g a pyknometer. 5 Reagents 5.1 General Use only degassed water in accordance with at least grade3 of ISO3696:1987. 5.2 Potassium dichromate-sulfuric acid solution, to clean the pyknometer(6.4) SAFETY WARNING. Extreme care should be exercised when using and transporting potassium dichromate-sulfuric
25、acid solution, which is a strong acid and oxidant. Take appropriate measures to protect skin, eyes and clothing. Never add water to this solution, since a large amount of heat will be generated locally, resulting in danger of sputtering. Take appropriate measures when disposing of used solutions. 5.
26、3 Appropriate glass cleaning agent, with cleansing effect comparable to(5.2) alternative to(5.2). 6 Apparatus Usual laboratory apparatus and, in particular, the following: 6.1 Desiccator with drying agent. 6.2 Water-bath, adjustable to20 C 0,05 C. 6.3 Analytical balance, accurate to0,1mg. 6.4 Reisch
27、auer pyknometer, nominal capacity50ml, with ground glass stopper, with a neck6cm long and not more than3,5mm internal diameter, provided in the middle third with a mark or scale. 6.5 Wide-mouthed pyknometer, if the relative density of a concentrated product and fruit pulp is to be determined(alterna
28、tive to6.4). 6.6 Funnel, diameter10cm. 6.7 Fluted filter paper 6.8 Watch-glass, diameter12cm to15cm. 6.9 Wicks of filter paper 6.10 Bent glass capillary tube 7 Procedure 7.1 Preparation of test sample If the sample contains appreciable quantities of carbon dioxide, degas it using vacuum or ultrasoun
29、d, followed by filtration through a fluted filter paper(6.7) in a funnel(6.6) covered by a watch-glass(6.8). In the case of a cloudy sample, homogenize by vigorous shaking to suspend any precipitate. Do not perform any filtration or clarification of the sample in this case. 7.2 Weighing of the empty
30、 pyknometer If necessary, clean the pyknometer(6.4) with hot potassium dichromate-sulfuric acid solution(5.2) or a proprietary cleansing agent(5.3). SAFETY WARNING. Seesafety warning in(5.2). Rinse the pyknometer(6.4) several times with water and dry gently. Avoid drying conditions that might influe
31、nce the volume of the pyknometer. After allowing the pyknometer to cool to ambient temperature in the desiccator(6.1) place it in the balance-case and allow to equilibrate in the balance-case for15min. weigh the pyknometer(6.4) to an accuracy of4decimal places. Carry out the rinsing, drying and weig
32、hing procedure a total of three times and then determine the mean mass value(m a ). 7.3 Weighing of the pyknometer filled with water Fill the pyknometer(6.4 or 6.5) to above the mark with freshly boiled air-free water, stopper and place in the water bath(6.2) at20 C 0,05 C for30min.EN1131:1994 4 BSI
33、 12-1999 While still keeping it in the water bath, bring the volume of the water to the mark by means of the bent glass capillary tube(6.10). Ensure that the adjustment of the liquid level is always carried out by the same method. The surface of the water forms a curved area in the neck of the pykno
34、meter. Adjust the liquid so that in transmitted light, the lower edge of the surface just touches the pyknometer mark. Then dry the empty part of the pyknometer neck using the filter paper wicks(6.9). Replace the stopper, remove the pyknometer from the water-bath, dry well on the outside and place i
35、n the balance-case for15min. Weigh the pyknometer to an accuracy of4decimal places. Carry out this procedure of filling and weighing three times and then determine the mean mass(m b ). 7.4 Weighing of the pyknometer filled with test sample Empty the pyknometer after weighing it(7.3), then either dry
36、 as in7.2 or rinse repeatedly with the sample to be examined. Fill the pyknometer with the sample and proceed as in7.3 to determine the mean mass(m c ). 8 Calculation Calculate the relative density d 20 C/20 Cof the sample as follows: d 20 C/20 C = Express the relative density d 20 C/20 Cof the test
37、 sample to four decimal places. 9 Precision Details of the interlaboratory test on the precision of the method are summarized in Annex B. The values derived from the interlaboratory test may not be applicable to analyte concentration ranges and matrices other than given in Annex B. 9.1 Repeatability
38、 The absolute difference between two single test results found on identical test material by one operator using the same apparatus within the shortest feasible time interval will exceed the repeatability value r in not more than5% of the cases. The value is: r=0,00018. 9.2 Reproducibility The absolu
39、te difference between two single test results on identical test material reported by two laboratories will exceed the reproducibility value R in not more than5% of the cases. The value is: R=0,00029. 10 Test report The test report shall contain the following data: all information necessary for the i
40、dentification of the sample(kind of sample, origin of sample, designation); a reference to this European Standard; the date and type of sampling procedure(if possible); the date of receipt; the date of test; the test results and units in which they have been expressed; whether the repeatability of t
41、he method has been verified; any particular points observed in the course of the test; any operations not specified in the method or regarded as optional, which might have affected the results. where: m a is the mean mass of the empty pyknometer in grams; m b is the mean mass of the pyknometer fille
42、d with water at20 C, in grams; m c is the mean mass of the pyknometer filled with test sample at20 C, in grams. m c m a m b m a -EN1131:1994 BSI 12-1999 5 Annex A (informative) Bibliography 1 Determination of the relative density d 20/20 : No1,1989. In: Analyses Collection/International Federation o
43、f Fruit Juice Producers. Loose-leaf edition, as of1989. Zug: Swiss Fruit Union. 2 Untersuchung von Lebensmitteln: Bestimmung der relativen Dichte d 20/20in Fruchtsften:31.00-1,1980-05 Food Analysis: Determination of the relative density d 20/20in fruit juices: L31.00-1,1980-05 In: Amtliche Sammlung
44、von Untersuchungsverfahren nach 35 LMBG: Verfahren zur Probenahme und Untersuchung von Lebensmitteln, Tabakerzeugnissen, kosmetischen Mitteln und Bedarfsgenstnden/Bundesgesundheitsamt In: Collection of official methods under article35 of the German Federal Foods Act: Methods of sampling and analysis
45、 of foods, tobacco products, cosmetics and commodity goods/Federal Health Office Loseblattausgabe, Stand31.12.1991, Bd.I. Loose-leaf edition, as of1991-12-31, Vol.I. Berlin, Kln: Beuth Verlag GmbH. Annex B (informative) Statistical results of the interlaboratory test In accordance with ISO5725:1986,
46、 the following parameters have been defined in an interlaboratory test. (For literature pertaining to the method seeAnnex A). The test was conducted by the Max von Pettenkofer Institute of the Federal Health Office, Food Chemistry Department, Berlin, BRD: Table B.1 Year of interlaboratory test 1977
47、Number of laboratories 13 Number of samples 4 Sample A B C D Number of laboratories retained after eliminating outliers Number of outliers(laboratories) Number of accepted results 10 3 50 9 4 48 10 3 50 10 3 50 Mean value () 1,04600 1,05108 1,05992 1,06873 Repeatability standard deviation(s r ) Repe
48、atability relative standard deviation (RSD r ) % 0,000074 0,0071 0,000058 0,0055 0,000055 0,0052 0,000065 0,0061 Repeatability limit (r) 0,00021 0,00016 0,00015 0,00018 Repeatability standard deviation (s R ) Reproducibilityrelative standard deviation (RSD R ) % 0,00012 0,0105 0,00010 0,0095 0,00010
49、 0,0094 0,00009 0,0084 Reproducibility limit (R) 0,00034 0,00028 0,00028 0,00025 Sample types: Aorange juice Bapple juice Cblack current nectar Dgrape juice, white x6 blankBSEN1131:1995 BSI 12-1999 National annex NA (informative) Committees responsible The United Kingdom participation in the preparation of this European Standard was entrusted to Technical Committee AW/21, Fruit and vegetable juices, upon which the following bodies were represented
