DIN EN ISO 27971-2015 Cereals and cereal products - Common wheat (Triticum aestivum L ) - Determination of alveograph properties of dough at constant hydration from commercial or t7.pdf

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1、November 2015English price group 26No part of this translation may be reproduced without prior permission ofDIN Deutsches Institut fr Normung e. V., Berlin. Beuth Verlag GmbH, 10772 Berlin, Germany,has the exclusive right of sale for German Standards (DIN-Normen).ICS 67.060!%G“2365725www.din.deDIN E

2、N ISO 27971Cereals and cereal products Common wheat (Triticum aestivum L.) Determination of alveograph properties of dough at constant hydration from commercial or test flours and test milling methodology (ISO 27971:2015);English version EN ISO 27971:2015,English translation of DIN EN ISO 27971:2015

3、-11Getreide und Getreideerzeugnisse Weizen (Triticum aestivum L.) Bestimmung der Eigenschaften von Teig bei konstanter Flssigkeitszufuhr zu handelsblichen Mehlen oder Versuchsmehlen bei gleichen Versuchsmahlverfahren mittels Alveograph (ISO 27971:2015);Englische Fassung EN ISO 27971:2015,Englische b

4、ersetzung von DIN EN ISO 27971:2015-11Crales et produits craliers Bl tendre (Triticum aestivum L.) Dtermination des proprits alvographiques dune pte hydratation constante de farine industrielle ou dessai et mthodologie pour la mouture dessai (ISO 27971:2015);Version anglaise EN ISO 27971:2015,Traduc

5、tion anglaise de DIN EN ISO 27971:2015-11SupersedesDIN EN ISO 27971:2008-10www.beuth.deDTranslation by DIN-Sprachendienst.In case of doubt, the German-language original shall be considered authoritative.Document comprises 72 pages11.15 DIN EN ISO 27971:2015-11 2 A comma is used as the decimal marker

6、. National foreword This document (EN ISO 27971:2015) contains, unchanged, the International Standard ISO 27971:2015, which had been prepared by Technical Committee ISO/TC 34 “Food products” (Secretariat: France/Brazil), Subcommittee SC 4 “Cereals and pulses” (Secretariat: China). Based on the resul

7、ts of parallel voting under the leadership of ISO/TC 34/SC 4, Technical Committee CEN/TC 338 decided to adopt the International Standard as a European Standard. The responsible German body involved in its preparation was DIN-Normenausschuss Lebensmittel und landwirtschaftliche Produkte (DIN Standard

8、s Committee Food and Agricultural Products), Working Committee NA 057-05-06 AA Getreide und Getreideerzeugnisse. The DIN Standards corresponding to the International Standards referred to in this document are as follows: ISO 660 DIN EN ISO 660 ISO 712 DIN EN ISO 712 ISO 12099 DIN EN ISO 12099 Amendm

9、ents This standard differs from DIN EN ISO 27971:2008-10 as follows: a) the method has been revised and brought in line with the state of the art; b) the description of the method has been editorially revised. Previous editions DIN EN ISO 27971: 2008-10 Nationale Annex NA (informative) Bibliography

10、DIN EN ISO 660, Animal and vegetable fats and oils Preparation of test sample DIN EN ISO 712, Cereals and cereal products Determination of moisture content Reference method DIN EN ISO 12099, Animal feeding stuff, cereals and milled cereal products Guidelines for the application of near infrared spec

11、trometry EN ISO 27971June 2015ICS 67.060 Supersedes EN ISO 27971:2008English VersionCerealsandcerealproducts-Commonwheat(Triticumaestivum L.) - Determination of alveograph properties of doughat constant hydration from commercial or test flours and testmilling methodology (ISO 27971:2015)Crales e tpr

12、oduits craliers -Bl tendre (Triticumaestivum L.) - Dtermination des propritsalvographiques dune pte hydratation constante defarine industrielle ou dessai et mthodologie pour lamouture dessai (ISO 27971:2015)Getreide und Getreideerzeugnisse - Weizen (Triticumaestivum L.) - Bestimmung der Eigenschafte

13、n von Teig beikonstanter Flssigkeitszufuhr zu handelsblichen Mehlenoder Versuchsmehlen bei gleichen Versuchsmahlverfahrenmittels Alveograph (ISO 27971:2015)This European Standard was approved by CEN on 16 April 2015. CEN members are bound to comply with the CEN/CENELEC Internal Regulations which sti

14、pulate 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-CENELEC Management Centre or to any CEN member. This European

15、 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-CENELEC Management Centre has the same status as the official versions. CEN members are th

16、e national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romani

17、a, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey andUnited Kingdom. CEN-CENELEC Management Centre: Avenue Marnix 17, B-1000 Brussels 2015 CEN All rights of exploitation in any form and by any means reserved worldwide for CEN national Members. Ref. No. EN ISO 27971:2015 EEUROPEAN COMMITTEE F

18、OR STANDARDIZATIONCOMIT EUROPEN DE NORMALISATIONEUROPISCHES KOMITEE FR NORMUNGEUROPEAN STANDARDNORME EUROPENNEEUROPISCHE NORMContents Page Foreword .4 Introduction .5 1 Scope .6 2 Normative references6 3 Principle .6 4 Reagents .6 5 Apparatus 7 6 Sampling . 14 7 Preparation of the wheat for laborato

19、ry milling 15 7.1 Cleaning the laboratory sample 15 7.2 Test portion . 15 7.3 Wheat moisture content determination 15 7.4 Wheat preparation . 15 7.4.1 General 15 7.4.2 Wheat with initial moisture content between 13 % and 15 % (one-stage moistening) 15 7.4.3 Wheat with a moisture content less than 13

20、 % (two-stage moistening) 15 7.4.4 Wheat with a moisture content greater than 15 % (preliminary drying followed by moistening, as described above) 16 8 Laboratory milling 16 8.1 General . 16 8.2 Milling procedure 16 8.2.1 Breaking . 16 8.2.2 Reduction . 16 8.2.3 Flour homogenization 17 8.2.4 Storage

21、 of the flour 17 8.3 Expression of milling results 17 9 Preparation and alveograph test . 18 9.1 Preliminary checks . 18 9.2 Preliminary operations . 19 9.3 Kneading . 20 9.4 Preparation of dough test pieces 21 9.5 Alveograph test 25 9.5.1 Initial preparation 25 9.5.2 First operation: Adjusting the

22、dough test piece 26 9.5.3 Second operation: biaxial extension. 27 9.6 Expression of alveograph test results . 28 9.6.1 General 28 9.6.2 Maximum pressure parameter, P . 28 9.6.3 Mean abscissa at rupture, L . 28 9.6.4 Swelling index, G . 29 9.6.5 Elasticity index 29 9.6.6 Curve configuration ratio, P/

23、L . 29 9.6.7 Deformation work, W . 29 2DIN EN ISO 27971:2015-11 EN ISO 27971:2015 (E) 10 Precision . 29 10.1 Interlaboratory tests 29 10.2 Repeatability limits 30 10.2.1 Commercial flour: limits established by the interlaboratory test 30 10.2.2 Flour obtained from laboratory milling 30 10.3 Reproduc

24、ibility limits 30 10.3.1 Commercial flour: Limits established by the proficiency tests . 30 10.3.2 Flour obtained from laboratory milling 31 10.4 Uncertainty 31 11 Test report . 31 Annex A (informative) Characteristics of the Chopin-Dubois CD1 mil 32 Annex B (normative) Quantity of water to be added

25、 to wheat for conditioning . 34 Annex C (informative) Sample milling sheet 36 Annex D (informative) Conversion table from L to G . 37 Annex E (informative) Interlaboratory and proficiency test data for commercial flours 39 Annex F (informative) Interlaboratory data for laboratory milled flour . 49 A

26、nnex G (informative) Routine maintenance instructions for the alveograph 66 Annex H (informative) Assessment of proteolytic activity in wheat (T. aestivum L.) or flour . 68 Bibliography . 70 3DIN EN ISO 27971:2015-11EN ISO 27971:2015 (E)Foreword This document (EN ISO 27971:2015) has been prepared by

27、 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. This European Standard shall be given the status of a national standard, either by publication of an identical text or by endors

28、ement, at the latest by December 2015, and conflicting national standards shall be withdrawn at the latest by December 2015. Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. CEN and/or CENELEC shall not be held responsible for iden

29、tifying any or all such patent rights. This document supersedes EN ISO 27971:2008. According to the CEN-CENELEC Internal Regulations, the national standards organizations of the following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Repu

30、blic, Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the United Kingdom. Endo

31、rsement notice The text of ISO 27971:2015 has been approved by CEN as EN ISO 27971:2015 without any modification. 4DIN EN ISO 27971:2015-11 EN ISO 27971:2015 (E) IntroductionThe end-use value of wheat is determined by a number of properties that are useful in the manufacture of baked products such a

32、s bread, rusks, and biscuits.Such properties include the important viscoelastic (rheological) properties of dough formed as a result of flour hydration and kneading. An alveograph is used to study the main parameters by subjecting a dough test piece to biaxial extension (producing a dough bubble) by

33、 inflating it with air, which is similar to the deformation to which it is subjected during panary fermentation.Recording the pressure generated inside the bubble throughout the deformation of the dough test piece until it ruptures provides information on the following:a) the resistance of the dough

34、 to deformation, or its strength. It is expressed by the maximum pressure parameter, P;b) the extensibility or the possibility of inflating the dough to form a bubble; It is expressed by the parameters of extensibility, L, or swelling, G;c) the elasticity of the dough during biaxial extension. It is

35、 expressed by the elasticity index, Ie;d) the work required to deform the dough bubble until it ruptures, which is proportional to the area of the alveogram (sum of the pressures throughout the deformation process). It is expressed by the parameter, W.The P/L ratio is a measurement of the balance be

36、tween strength and extensibility.Alveographs are commonly used throughout the wheat and flour industry, for the following purposes: selecting and assessing different varieties of wheat and marketing batches of wheat; blending different batches of wheat or flour to produce a batch with given values f

37、or the alveographic criteria (W, P, and L) complying with the proportional laws of blending.Alveographs are used both on the upstream side of the industry for marketing, selecting and assessing the different wheat varieties and on the downstream side throughout the baking industries (see Bibliograph

38、y).5DIN EN ISO 27971:2015-11EN ISO 27971:2015 (E)1 ScopeThis International Standard specifies a method of determining, using an alveograph, the rheological properties of different types of dough obtained from common wheat flour (Triticum aestivum L.) produced by industrial milling or laboratory mill

39、ing.It describes the alveograph test and how to use a laboratory mill to produce flour in two stages: stage 1: preparation of the wheat grain for milling to make it easier to separate the bran from the endosperm (see Clause 7); stage 2: the milling process, including breaking between three fluted ro

40、llers, reduction of particle size between two smooth rollers and the use of a centrifugal sieving machine to grade the products (see Clause 8).2 Normative referencesThe following documents, in whole or in part, are normatively referenced in this document and are indispensable for its application. Fo

41、r dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.ISO 660, Animal and vegetable fats and oils Determination of acid value and acidityISO 712, Cereals and cereal products Determination of moistu

42、re content Reference methodISO 12099, Animal feeding stuffs, cereals and milled cereal products Guidelines for the application of near infrared spectrometry3 PrincipleThe behaviour of dough obtained from a mixture of different types of flour and salt water is evaluated during deformation. A dough di

43、sk is subjected to a constant air flow; at first it withstands the pressure. Subsequently, it inflates into a bubble, according to its extensibility, and ruptures. The change in the dough is measured and recorded in the form of a curve called an alveogram.4 ReagentsUnless otherwise specified, use on

44、ly reagents of recognized analytical grade, and only distilled or demineralized water or water of equivalent purity.4.1 Sodium chloride solution, obtained by dissolving (25 0,2) g of sodium chloride (NaCl) in water and then making the volume up to 1 000 ml. This solution shall not be stored for more

45、 than 15 d and its temperature shall be (20 2) C when used.4.2 Refined vegetable oil, low in polyunsaturates, such as peanut oil. It is possible to use olive oil if its acid value is less than 0,4 (determined according to ISO 660). Store in a dark place in a closed container and replace regularly (a

46、t least every three months).Alternatively, liquid paraffin (also known as “soft petroleum paraffin”), with an acid value of less than or equal to 0,05 and the lowest possible viscosity maximum 60 mPas (60 cP) at 20 C.4.3 Cold degreasing agent, optimum safety.6DIN EN ISO 27971:2015-11 EN ISO 27971:20

47、15 (E) 5 ApparatusUsual laboratory apparatus and, in particular, the following.5.1 Mechanical cleaner, fitted with sieves for wheat cleaning, in accordance with the manufacturers instructions.5.2 Conical or riffle sample divider.5.3 Analytical balance, accurate to 0,01 g.5.4 Glass burette, of 50 ml

48、in capacity, graduated in 1 ml divisions.5.5 Rotary blender1), for grain conditioning and flour homogenization, including the following components:5.5.1 Constant speed stirrer.5.5.2 Two worm screws integral with the flask, possibly via the stopper (one for wheat preparation, the other for flour homo

49、genization).5.5.3 Several wide-necked plastic flasks, 2 l capacity.5.6 Test mill (laboratory mill), manually or automatically operated (see Annex A).5.7 Complete alveograph system (see Table 1 for specifications and characteristics of the accessories) including the following devices:5.7.1 Kneading machine for models MA 82, MA 87, and MA 95, see Figure 1 a); for model NG, see label a in Figure 2 and Figure 3, with accur