EN ISO 2171-2010 en Cereals pulses and by-products - Determination of ash yield by incineration《谷类食品 豆类及其副产品 焚化后灰分的测定》.pdf

1、BRITISH STANDARDBS EN ISO 2171:2010Cereals, pulses and by-products Determination of ash yield by incinerationICS 67.060g49g50g3g38g50g51g60g44g49g42g3g58g44g55g43g50g56g55g3g37g54g44g3g51g40g53g48g44g54g54g44g50g49g3g40g59g38g40g51g55g3g36g54g3g51g40g53g48g44g55g55g40g39g3g37g60g3g38g50g51g60g53g44g

2、42g43g55g3g47g36g58National forewordThis British Standard is the UK implementation of EN ISO 2171:2010. It is identical to ISO 2171:2007. It supersedes BS ISO 2171:2007 which is withdrawn.The UK participation in its preparation was entrusted to Technical Committee AW/4, Cereals and pulses.A list of

3、organizations represented on this committee can be obtained on request to its secretary.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 cannot confer immunity from legal obli

4、gations.BS EN ISO 2171:2010This British Standard was published under the authority of the Standards Policy and Strategy Committee on 30 November 2007 BSI 2010Amendments/corrigenda issued since publicationDate Comments 30 June 2010 This corrigendum renumbers BS ISO 2171:2007 as BS EN ISO 2171:2010ISB

5、N 978 0 580 69803 3EUROPEAN STANDARD NORME EUROPENNE EUROPISCHE NORM EN ISO 2171 April 2010 ICS 67.060 English Version Cereals, pulses and by-products - Determination of ash yield by incineration (ISO 2171:2007) Crales, lgumineuses et produits drivs - Dosage du taux de cendres par incinration (ISO 2

6、171:2007) Getreide, Hlsenfrchte und Nebenprodukte - Bestimmung des Aschegehalts durch Verbrennung (ISO 2171:2007) This European Standard was approved by CEN on 13 March 2010. CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this Euro

7、pean 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 CEN Management Centre or to any CEN member. This European Standard exists in three official versions (Engli

8、sh, 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 CEN Management Centre has the same status as the official versions. CEN members are the national standards bodies of Austria, Belgium, Bulgaria,

9、 Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom. EUROPEAN COMMITTEE FOR STAN

10、DARDIZATION COMIT EUROPEN DE NORMALISATION EUROPISCHES KOMITEE FR NORMUNG Management Centre: Avenue Marnix 17, B-1000 Brussels 2010 CEN All rights of exploitation in any form and by any means reserved worldwide for CEN national Members. Ref. No. EN ISO 2171:2010: EForeword The text of ISO 2171:2007

11、has been prepared by Technical Committee ISO/TC 34 “Food products” of the International Organization for Standardization (ISO) and has been taken over as EN ISO 2171:2010 by Technical Committee CEN/TC 338 “Cereal and cereal products” the secretariat of which is held by AFNOR. This European Standard

12、shall be given the status of a national standard, either by publication of an identical text or by endorsement, at the latest by October 2010, and conflicting national standards shall be withdrawn at the latest by October 2010. Attention is drawn to the possibility that some of the elements of this

13、document may be the subject of patent rights. CEN and/or CENELEC shall not be held responsible for identifying any or all such patent rights. According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following countries are bound to implement this European Standa

14、rd: Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and the United K

15、ingdom. Endorsement notice The text of ISO 2171:2007 has been approved by CEN as a EN ISO 2171:2010 without any modification. BS EN ISO 2171:2010EN ISO 2171:2010 (E)iiiContents Page 1 Scope . 1 2 Normative references . 1 3 Terms and definitions. 1 4 Principle. 2 5 Reagents 2 6 Apparatus 2 7 Sampling

16、 3 8 Preparation of the test sample 3 9 Procedure 3 9.1 Determination of the moisture content. 3 9.2 Preparation of the ashing dishes 3 9.3 Preparation of the test portion 4 9.4 Pre-ashing . 4 9.5 Ashing 4 9.6 Number of determinations . 4 10 Expression of results . 4 11 Precision 5 11.1 Interlaborat

17、ory tests . 5 11.2 Repeatability 5 11.3 Reproducibility 5 11.4 Critical difference 6 11.5 Uncertainty 6 12 Test report . 6 Annex A (informative) Results of interlaboratory tests 8 Annex B (informative) Practical application of repeatability and reproducibility limits . 10 Bibliography . 11 BS EN ISO

18、 2171:2010EN ISO 2171:2010 (E)This page deliberately set blank1Cereals, pulses and by-products Determination of ash yield by incineration 1 Scope This International Standard specifies a method for determining the ash yielded by cereals, pulses and their milled products intended for human consumption

19、. The source materials covered are: a) grains of cereals; b) flours and semolinas; c) milled products (bran and high bran content products, sharps); d) mixed cereal flours (mixes); e) cereal by-products other than milled products; and f) pulses and their by-products. This International Standard is n

20、ot applicable to starches and starch derivatives (see ISO 3593), to products intended for animal feeding stuffs (see ISO 5984), or to seeds. 2 Normative references The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited

21、applies. For undated references, the latest edition of the referenced document (including any amendments) applies. ISO 712, Cereals and cereal products Determination of moisture content Routine reference method ISO 6540, Maize Determination of moisture content (on milled grains and on whole grains)

22、ISO 24557:1), Pulses Determination of moisture content Air-oven method 3 Terms and definitions For the purposes of this document, the following terms and definitions apply. 3.1 ash incombustible residue obtained after incineration according to the method given in this International Standard 1) To be

23、 published. BS EN ISO 2171:2010EN ISO 2171:2010 (E)2 4 Principle A test portion is incinerated until combustion of organic matter is complete, then the residue obtained is weighed. The residue obtained is flaky after incineration at 550 C and vitrified after incineration at 900 C. In general, produc

24、ts containing salts (e.g. sodium chloride, pyrophosphate) shall be incinerated at (550 10) C. Table 1 summarizes incineration temperatures according to product type. Table 1 Incineration temperatures and product type Product type Incineration temperature Flours (550 10) C (900 25) C Semolinas (550 1

25、0) C (900 25) C Cereal grains (550 10) C (900 25) C Other milled products (e.g. bran, high bran content products, sharps) (550 10) C Mixed cereal products (mixes) (550 10) C Cereal by-products other than milled products (550 10) C Pulses and their by-products (550 10) C 5 Reagents Unless stated othe

26、rwise, use only reagents of recognized analytical quality and distilled or demineralized water or water of equivalent purity. 5.1 Hydrochloric acid, aqueous solution of one part by volume of HCl (35 % volume fraction) and one part by volume of water. 5.2 Purified diphosphorus pentoxide (P4O10). 5.3

27、Ethanol. 6 Apparatus 6.1 Grinding mill, easy to clean and having as little dead space as possible, and ensuring rapid, uniform grinding. 6.2 Ashing dish, of capacity not less than 20 ml, rectangular or round shape, flat-bottomed and having a surface area of not less than 12 cm2. Suitable materials f

28、or the ashing dish which do not deteriorate under test conditions at the temperature of operation are: a) at 900 C platinum or rhodium; b) at 550 C quartz or silica. In both cases, the material used shall allow compliance with the precision values. The dishes shall be cleaned by complete immersion f

29、or at least 1 h in hydrochloric acid (5.1), then rinsed with running water and then with distilled water. BS EN ISO 2171:2010EN ISO 2171:2010 (E)3After rinsing, the dishes shall be dried in an oven (6.7) at a temperature and for a period sufficient to eliminate water. 6.3 Electrically heated muffle

30、furnace, with adequate ventilation, provided with temperature control system and a refractory coating which is not liable to lose particles at the ashing temperature, and capable of being maintained at (900 25) C or at (550 10) C. 6.4 Vacuum desiccator, equipped with a perforated aluminium or porcel

31、ain plate, and diphosphorus pentoxide (5.2) as drying agent. 6.5 Analytical balance, with an accuracy of 0,01 mg. 6.6 Riffle splitter or cone-shaped divider. 6.7 Oven for drying the ashing dishes. 7 Sampling A representative sample should have been sent to the laboratory. It should not have been dam

32、aged or changed during transport or storage. Sampling is not part of the method specified in this International Standard. Recommended sampling methods are given in ISO 6644 and ISO 13690. 8 Preparation of the test sample For grains or products containing whole grains, mix and divide the sample in or

33、der to obtain a representative quantity compatible with the type of grinding mill (6.1) being used. Grind the sample thus obtained. The other products do not require grinding. 9 Procedure 9.1 Determination of the moisture content Determine beforehand the moisture content of the test sample in accord

34、ance with ISO 712 for cereals other than maize or ISO 6540 in the case of maize or ISO 24557 in the case of pulses. Pulses and their derived products should be processed according to ISO 712 with a 90 min drying time and preconditioning if moisture mass fraction is below 7 % or above 13 %. 9.2 Prepa

35、ration of the ashing dishes For ashing dishes suitable for use at 900 C (6.2), bring the previously cleaned dishes up to the incineration temperature being employed by putting them in the muffle furnace (6.3) for 5 min, leave them to cool in the desiccator (6.4), then weigh (6.5) them to within 0,1

36、mg. For ashing dishes suitable for use at 550 C, place the cleaned dishes in an oven (6.7) for the time required for drying (e.g. 90 min at 130 C). Immediately before use, remove the dishes from the oven and leave them to cool in a desiccator (6.4), then weigh (6.5) them to within 0,1 mg. BS EN ISO

37、2171:2010EN ISO 2171:2010 (E)4 9.3 Preparation of the test portion From the test sample prepared according to Clause 8 and carefully mixed, rapidly weigh (6.5) to within 0,1 mg a test portion between 3,9 g and 4,1 g in the case of incineration at 900 C and between 4,9 g and 5,1 g in the case of inci

38、neration at 550 C. In the case of low density products, the test portion can be between (2 0,1) g and (3 0,1) g. In the ashing dish, prepared and weighed as described in 9.2, spread out the product, without packing it, to form a uniform layer. 9.4 Pre-ashing Place the ashing dish and its contents at

39、 the entrance of the furnace brought up to the ashing temperature. At 900 C, the products burst into flame spontaneously. At 550 C, it is necessary to ignite them with ethanol (5.3). For pre-ashing at 550 C, it is permissible to put the dishes in the cold furnace and to let the temperature of the fu

40、rnace rise to the target temperature. 9.5 Ashing Wait until the product has finished burning, then place the dish inside the furnace. Close the furnace door. Continue the ashing until combustion of the entire product, including the carbon particles contained in the residue, is complete, namely 1 h m

41、inimum at 900 C, and 4 h minimum at 550 C. Once the ashing is completed, remove the dish from the furnace and place it in the desiccator (6.4) to cool. In order to maintain the efficiency of the desiccator, do not stack dishes. Due to the hygroscopic nature of the ash, as soon as the dish has reache

42、d ambient temperature (namely 15 min to 20 min for metallic dishes and 60 min to 90 min minimum for quartz or silica dishes), weigh rapidly to within 0,1 mg. For test portions incinerated at 550 C, special precautions shall be taken to avoid flaky residues being swept away with the influx of air on

43、opening the desiccator. The validity of the results obtained on this sample shall be checked with respect to the laboratorys self-inspection criteria (e.g. control chart). 9.6 Number of determinations Conduct at least two determinations on the same test sample. 10 Expression of results The ash yield

44、, as a mass fraction on the dry matter basis expressed as a percentage, wa,d, is given by Equation (1): wmmmw=a,d 2 10m100 100()100(1) BS EN ISO 2171:2010EN ISO 2171:2010 (E)5where m0is the mass, in grams, of the test portion (9.3); m1is the mass, in grams, of the ashing dish (9.2); m2is the mass, i

45、n grams, of the ashing dish (9.2) and the incinerated residue (9.5); wmis the moisture content, as a percentage by mass, of the sample (see 9.1). Take as a result the arithmetic mean of the two determinations if the repeatability conditions (see 11.1) are fulfilled. Express the result to the nearest

46、 0,01 % by mass. If needed, the ash yield, as mass fraction on the wet matter basis expressed as a percentage, wa,w, is given by Equation (2): wmmm=a,w 2 10100() (2) 11 Precision 11.1 Interlaboratory tests The values for repeatability and reproducibility limits and for critical differences were deri

47、ved from results of interlaboratory tests carried out in accordance with ISO 5725-1, ISO 5725-2, and ISO 5725-6. Details are summarized in Annex A. The values deriving from these interlaboratory tests may not be applicable to content ranges and matrices other than those given. 11.2 Repeatability The

48、 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 more than 5 % of cases be greater than: r = 2,8 sr(3) r = 2,8

49、0,009 = 0,025 for 0,49 % wa,du 1,00 % (4) r = 2,8 0,012 = 0,034 for 1,00 % wa,du 2,53 % (5) where sris the standard deviation of repeatability. 11.3 Reproducibility The absolute difference between two independent single test results, obtained using the same method on identical test material in different laboratories with different operators using different equipment, will in not more than 5 % of cases be greater than: R = 2,8 sR(6) R = 2,8 0,023 = 0,064 for 0,49