EN ISO 712-2009 en Cereals and cereal products - Determination of moisture content - Reference method《类和谷类制品 湿气含量的测定 参照法》.pdf

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1、BS EN ISO712:2009ICS 67.060NO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAWBRITISH STANDARDCereals andcereal products Determination ofmoisture content Reference method (ISO712:2009)This British Standard was published under the authority of the Standards Policy and Strategy Comm

2、ittee on 31 December 2009 BSI 2009ISBN 978 0 580 58496 1Amendments/corrigenda issued since publicationDate CommentsBS EN ISO 712:2009National forewordThis British Standard is the UK implementation of EN ISO 712:2009. Itsupersedes BS 4317-3:1999 which is withdrawn.The UK participation in its preparat

3、ion was entrusted to TechnicalCommittee AW/4, Cereals and pulses.A list of organizations represented on this committee can be obtained onrequest to its secretary.This publication does not purport to include all the necessary provisionsof a contract. Users are responsible for its correct application.

4、 Compliance with a British Standard cannot confer immunityfrom legal obligations.EUROPEAN STANDARD NORME EUROPENNE EUROPISCHE NORM EN ISO 712 November 2009 ICS 67.060 English Version Cereals and cereal products - Determination of moisture content - Reference method (ISO 712:2009) Crales et produits

5、craliers - Dtermination de la teneur en eau - Mthode de rfrence (ISO 712:2009) Getreide und Getreideerzeugnisse - Bestimmung des Feuchtegehaltes - Referenzverfahren (ISO 712:2009) This European Standard was approved by CEN on 14 November 2009. CEN members are bound to comply with the CEN/CENELEC Int

6、ernal 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 CEN Management Centre or to any CEN me

7、mber. 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 CEN Management Centre has the same status as the official versions. CEN mem

8、bers are the national standards bodies of Austria, Belgium, Bulgaria, 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,

9、 Switzerland and United Kingdom. EUROPEAN COMMITTEE FOR STANDARDIZATION COMIT EUROPEN DE NORMALISATION EUROPISCHES KOMITEE FR NORMUNG Management Centre: Avenue Marnix 17, B-1000 Brussels 2009 CEN All rights of exploitation in any form and by any means reserved worldwide for CEN national Members. Ref

10、. No. EN ISO 712:2009: EBS EN ISO 712:2009EN ISO 712:2009 (E) 3 Foreword This document (EN ISO 712:2009) has been prepared by Technical Committee ISO/TC 34 “Food products“ in collaboration with Technical Committee CEN/TC 338 “Cereal and cereal products” the secretariat of which is held by AFNOR. Thi

11、s European Standard shall be given the status of a national standard, either by publication of an identical text or by endorsement, at the latest by May 2010, and conflicting national standards shall be withdrawn at the latest by May 2010. Attention is drawn to the possibility that some of the eleme

12、nts of this 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 Eur

13、opean Standard: Austria, Belgium, Bulgaria, 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 Unite

14、d Kingdom. Endorsement notice The text of ISO 712:2009 has been approved by CEN as a EN ISO 712:2009 without any modification. BS EN ISO 712:2009ISO 712:2009(E) ISO 2009 All rights reserved iiiContents Page Foreword iv 1 Scope1 2 Terms and definitions .1 3 Principle1 4 Apparatus.1 5 Sampling.2 6 Pre

15、paration of the test sample.2 6.1 Products not requiring grinding 2 6.2 Products requiring grinding.3 6.2.1 General .3 6.2.2 Grinding without preconditioning .3 6.2.3 Grinding with preconditioning .3 7 Procedure.3 7.1 Number of determinations3 7.2 Test portion3 7.3 Drying .4 7.4 Weighing.4 8 Express

16、ion of results4 8.1 Without preconditioning.4 8.2 With preconditioning.4 9 Precision.5 9.1 Interlaboratory test5 9.2 Repeatability 5 9.3 Reproducibility 5 9.4 Comparison of two groups of measurements in one laboratory .5 9.5 Comparison of two groups of measurements in two laboratories.6 9.6 Uncertai

17、nty.6 10 Test report6 Annex A (informative) Results of interlaboratory test 7 Annex B (informative) Cereals and cereal products Determination of moisture content Absolute method .9 Bibliography16 BS EN ISO 712:2009ISO 712:2009(E) iv ISO 2009 All rights reservedForeword ISO (the International Organiz

18、ation for Standardization) is a worldwide federation of national standards 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

19、 has the right to be represented on that committee. International organizations, 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. I

20、nternational Standards are drafted in accordance with the rules given in the 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. Publ

21、ication as an International Standard requires approval by at least 75 % of 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

22、rights. ISO 712 was prepared by Technical Committee ISO/TC 34, Food products, Subcommittee SC 4, Cereals and pulses. This fourth edition cancels and replaces the third edition (ISO 712:1998), which has been technically revised. BS EN ISO 712:2009INTERNATIONAL STANDARD ISO 712:2009(E) ISO 2009 All ri

23、ghts reserved 1Cereals and cereal products Determination of moisture content Reference method 1 Scope This International Standard specifies a routine reference method for the determination of the moisture content of cereals and cereal products. This International Standard applies to: wheat, rice (pa

24、ddy, husked and milled), barley, millet (Panicum miliaceum), rye, oats, triticale, sorghum in the form of grains, milled grains, semolina or flour. The method is not applicable to maize and pulses. NOTE For moisture content determination in maize, see ISO 65405; and for pulses, see ISO 245577. 2 Ter

25、ms and definitions For the purposes of this document, the following terms and definitions apply. 2.1 moisture content mass loss undergone by a product under the conditions specified in this International Standard NOTE Moisture content is expressed as a percentage. 3 Principle If necessary, a laborat

26、ory sample is ground, after conditioning, if required. A test portion is dried at a temperature between 130 C and 133 C, under conditions which enable a result to be obtained which corresponds to that obtained by the absolute method described in Annex B. 4 Apparatus 4.1 Analytical balance, capable o

27、f weighing to an accuracy of 0,001 g. 4.2 Grinding mill, having the following characteristics: a) made of material which does not absorb moisture; b) easy to clean and having as little dead space as possible; c) enabling grinding to be carried out rapidly and uniformly, without appreciable developme

28、nt of heat (difference of temperatures before and after grinding smaller than or equal to 5 C); NOTE A grinding mill fitted with a cooling device can comply with this requirement. d) tightness to air to avoid water exchange between sample and external air; e) adjustable so as to obtain particles of

29、the dimensions indicated in Table 1. BS EN ISO 712:2009ISO 712:2009(E) 2 ISO 2009 All rights reserved4.3 Metal dish, non-corrodible under the test conditions, or glass dish, with a lid and having an effective surface area enabling the test portion to be distributed so as to give a mass per unit area

30、 of not more than 0,3 g/cm2. 4.4 Constant-temperature oven, electrically heated, controlled in such a way that, during normal working, the temperature of the air and of the shelves carrying the test portions is maintained within the range 130 C to 133 C in the vicinity of the test portions. The oven

31、 shall have a heat capacity such that, when initially adjusted to a temperature of 131 C, it can regain this temperature in less than 30 min after insertion of the maximum number of test portions that can be dried simultaneously. The effectiveness of the ventilation shall be determined using durum w

32、heat semolina, of maximum particle size of 1 mm, as the test material. The ventilation shall be such that, after insertion of the maximum number of test portions that the oven can accommodate, and drying at a temperature of 130 C to 133 C, the results, after heating the same test portions for 2 h an

33、d then for a further 1 h, do not differ by more than 0,15 g of moisture per 100 g of sample. 4.5 Desiccator, containing an effective desiccant. 5 Sampling Sampling is not part of the method specified in this International Standard. A recommended sampling method is given in ISO 243336. A representati

34、ve sample, in an airtight packaging, should have been sent to the laboratory. It should not have been damaged or changed during transport or storage. 6 Preparation of the test sample 6.1 Products not requiring grinding Products having particle size characteristics indicated in Table 1 do not need to

35、 be ground before the determination. Mix the laboratory sample thoroughly before taking the test portion (7.2). Table 1 Particle size characteristics of products not requiring grinding Particle size characteristics mm Proportion % u 1,7 (1,8)a100 1,0 (1,0)bu 10 0,5 (0,56)aW 50 a Nominal size of open

36、ings, ISO 3310-11, that does not retain this particle size. b Nominal size of openings, ISO 3310-11, that retains this particle size. BS EN ISO 712:2009ISO 712:2009(E) ISO 2009 All rights reserved 36.2 Products requiring grinding 6.2.1 General If the products do not have the particle size characteri

37、stics mentioned in Table 1, they shall be ground either without preconditioning (6.2.2) or with preconditioning (6.2.3), as required. 6.2.2 Grinding without preconditioning For products that are not likely to undergo variations in moisture content during grinding (in general, products with a moistur

38、e content between 9 % and 15 %), grind without preconditioning. NOTE The range of moisture contents given for conditioning products before grinding corresponds approximately in the laboratory to a temperature of 20 C and a relative humidity of 40 % to 70 %. Adjust the grinding mill (4.2) to obtain p

39、articles of the dimensions indicated in Table 1. Then, quickly grind a quantity of the laboratory sample according to the apparatus used and at least slightly greater than that required for the test portion (about 5 g), and immediately proceed in accordance with 7.2. 6.2.3 Grinding with precondition

40、ing Products which are likely to undergo changes in moisture content during the course of grinding (in general, products with a moisture content greater than 15 % or less than 9 %) shall be preconditioned so as to bring their moisture content to between 9 % and 15 % before grinding. If the moisture

41、content is more than 15 % (the most frequent case), weigh, to the nearest 0,001 g, a sufficient quantity of the laboratory sample to provide a test portion slightly greater than 5 g (see 6.2.2). Record the mass of the test portion before preconditioning and dish as m2. Pre-dry in accordance with 7.3

42、, except that the time of heating in the oven (4.4) shall be 7 min to 10 min and the product shall be cooled to laboratory temperature with the dish (4.3) uncovered and without a desiccator, for at least 2 h. NOTE It is possible that these times are not be suitable for all products, e.g. paddy rice.

43、 For products having moisture contents of less than 9 %, weigh, to the nearest 0,001 g, a sufficient quantity of the laboratory sample to provide a test portion slightly greater than 5 g (see 6.2.2). Record the mass of the test portion before preconditioning and dish as m2. Place in a suitable atmos

44、phere (generally that of the laboratory) and leave until a moisture content within the limits indicated above is obtained. After conditioning, weigh the sample to the nearest 0,001 g. Record the mass of the test portion after preconditioning and dish as m3. Grind immediately, adjusting the grinder s

45、o as to obtain particles of the dimensions indicated in Table 1, and immediately proceed in accordance with 6.2.2. 7 Procedure 7.1 Number of determinations Carry out separate determinations on two test portions taken from the laboratory sample in accordance with 7.2 and 7.3. If the absolute differen

46、ce between the two values obtained is greater than the repeatability limit given in Clause 9, repeat the determination until requirements are satisfied. 7.2 Test portion Rapidly weigh, to the nearest 0,001 g, a quantity of 5 g 1 g of the laboratory sample (6.2.2 or 6.2.3) in the dish (4.3). Record t

47、he mass of the undried test portion and dish as m0. Previously dry and tare the dish, together with its lid, and record the mass, md, to the nearest 0,001 g. BS EN ISO 712:2009ISO 712:2009(E) 4 ISO 2009 All rights reserved7.3 Drying Place the open dish containing the test portion (7.2), together wit

48、h the lid, in the oven (4.4) and leave for 120 min 5 min (90 min for flours). In certain cases and particularly in hot and dry countries, the drying period may be reduced to 60 min 5 min, which is sufficient time for the test portions to attain constant mass. Review these times regularly. Do not ope

49、n the door of the oven during drying and do not place moist products in the oven before removing the dry test portions, as this will result in partial rehydration of the latter. After drying, quickly remove the dish from the oven, cover, and place in the desiccator (4.5). When several tests are being carried out, never place dishes on top of one another in the desiccator, but place them side by side. 7.4 Weighing When the dish has cooled to laboratory temperature (generally between 30 min and 45 min after it has