CEN TS 15731-2008 Cereals and cereal products - Common wheat (Triticum aestivum L ) - Determination of alveograph properties of dough at adapted hydration from commercial or test f.pdf

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1、DD CEN/TS15731:2008ICS 67.060NO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAWDRAFT FOR DEVELOPMENTCereals and cerealproducts Commonwheat (Triticumaestivum L.) Determination ofalveograph propertiesof dough at adaptedhydration fromcommercial or testflours and test millingmethodol

2、ogyThis Draft for Developmentwas published under theauthority of the StandardsPolicy and StrategyCommittee on 31 May 2009 BSI 2009ISBN 978 0 580 60107 1Amendments/corrigenda issued since publicationDate CommentsDD CEN/TS 15731:2008National forewordThis Draft for Development is the UK implementation

3、of CEN/TS15731:2008.This publication is not to be regarded as a British Standard.It is being issued in the Draft for Development series of publications andis of a provisional nature. It should be applied on this provisional basis,so that information and experience of its practical application can be

4、obtained.Comments arising from the use of this Draft for Development arerequested so that UK experience can be reported to the internationalorganization responsible for its conversion to an international standard.A review of this publication will be initiated not later than 3 years afterits publicat

5、ion by the international organization so that a decision can betaken on its status. Notification of the start of the review period will bemade in an announcement in the appropriate issue of Update Standards.According to the replies received by the end of the review period,the responsible BSI Committ

6、ee will decide whether to support theconversion into an international Standard, to extend the life of theTechnical Specification or to withdraw it. Comments should be sent tothe Secretary of the responsible BSI Technical Committee at BritishStandards House, 389 Chiswick High Road, London W4 4AL.The

7、UK participation in its preparation 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 responsi

8、ble for its correct application.Compliance with a British Standard cannot confer immunityfrom legal obligations.DD CEN/TS 15731:2008TECHNICAL SPECIFICATIONSPCIFICATION TECHNIQUETECHNISCHE SPEZIFIKATIONCEN/TS 15731August 2008ICS 67.060English VersionCereals and cereal products - Common wheat (Triticu

9、maestivum L.) - Determination of alveograph properties of doughat adapted hydration from commercial or test flours and testmilling methodologyCrales et produits craliers - Bl tendre (Triticumaestivum L.) - Dtermination des propritsalvographiques dune pte hydratation constanteadapte de farine industr

10、ielle ou dessai et mthodologiepour la mouture dessaiGetreide und Getreideerzeugnisse - Weizen (Triticumaestivum L.) - Bestimmung der Eigenschaften von Teig beiadaptierter Flssigkeitszufuhr zu handelsblichen Mehlenoder Versuchsmehlen bei gleichen Versuchsmahlverfahrenmittels AlveographThis Technical

11、Specification (CEN/TS) was approved by CEN on 9 March 2008 for provisional application.The period of validity of this CEN/TS is limited initially to three years. After two years the members of CEN will be requested to submit theircomments, particularly on the question whether the CEN/TS can be conve

12、rted into a European Standard.CEN members are required to announce the existence of this CEN/TS in the same way as for an EN and to make the CEN/TS availablepromptly at national level in an appropriate form. It is permissible to keep conflicting national standards in force (in parallel to the CEN/TS

13、)until the final decision about the possible conversion of the CEN/TS into an EN is reached.CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Cyprus, Czech Republic, Denmark, Estonia, Finland,France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Lux

14、embourg, Malta, Netherlands, Norway, Poland, Portugal,Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.EUROPEAN COMMITTEE FOR STANDARDIZATIONCOMIT EUROPEN DE NORMALISATIONEUROPISCHES KOMITEE FR NORMUNGManagement Centre: rue de Stassart, 36 B-1050 Brussels 2008 CEN All right

15、s of exploitation in any form and by any means reservedworldwide for CEN national Members.Ref. No. CEN/TS 15731:2008: EDD CEN/TS 15731:2008CEN/TS 15731:2008 (E) 2 Contents Page Foreword. 4 Introduction 5 1 Scope . 6 2 Normative references . 6 3 Principle. 6 4 Reagents 7 5 Apparatus 7 6 Sampling 12 7

16、 Preparation of the wheat for test milling 13 7.1 Cleaning the laboratory sample 13 7.2 Test portion . 13 7.3 Determining the moisture content of wheat. 13 7.4 Wheat conditioning. 13 7.4.1 General. 13 7.4.2 Case of wheat with an initial moisture content of between 13 % and 15 %: (one-stage moistenin

17、g) 13 7.4.3 Case of wheat with a moisture content less than 13 %:( two-stage moistening). . 13 7.4.4 Wheat with a moisture content greater than 15 %: preliminary drying followed by conditioning, as described above. 14 8 Laboratory milling. 14 8.1 General. 14 8.2 Milling procedure 14 8.2.1 Break syst

18、em. 14 8.2.2 Reduction system . 15 8.2.3 Flour homogenisation 15 8.2.4 Storage of the flour. 15 8.3 Expression of milling results. 16 9 Preparation and Alveograph test 16 9.1 Preliminary checks . 16 9.2 Preliminary operations. 20 9.3 Determination of flour water absorption capacity. 20 9.4 Kneading

19、21 9.5 Preparation of dough test pieces 21 9.6 Alveograph test. 23 9.7 Expression of the results of the Alveograph test at adapted hydration . 27 9.7.1 General. 27 9.7.2 Maximum pressure parameter “T” 27 9.7.3 Average abscissa at rupture “A” 28 9.7.4 Index of swelling “Ex” 28 9.7.5 Elasticity index

20、“Iec” 28 9.7.6 “T/A” ratio 28 9.7.7 Deformation energy “Fb”. 28 10 Test report . 29 Annex A (informative) Characteristics of the Chopin-Dubois CD1 mill 30 A.1 Break system. 30 A.2 Reduction system . 30 A.3 Sieve material 30 A.3.1 Post-break . 30 A.3.2 Post-reduction. 30 A.4 Milling. 31 A.5 Break per

21、formance indicator. 31 A.6 Conversion performance indicator . 31 A.7 Maintenance operations. 31 Annex B (normative) Moisture required to condition wheat 32 DD CEN/TS 15731:2008CEN/TS 15731:2008 (E) 3 Annex C (informative) Example milling sheet 33 Annex D (informative) Calculated values of “Ex” 35 An

22、nex E (informative) Routine maintenance instructions for the alveograph .36 E.1 Before every trial .36 E.2 Every day36 E.3 Every week .36 E.4 Every month .36 E.5 Every year.37 Bibliography38 DD CEN/TS 15731:2008CEN/TS 15731:2008 (E) 4 Foreword This document (CEN/TS 15731:2008) has been prepared by T

23、echnical Committee CEN/TC 338 “Cereals and cereal products”, the secretariat of which is held by AFNOR. Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. CEN shall not be held responsible for identifying any or all such patent right

24、s. According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following countries are bound to announce this Technical Specification: Austria, Belgium, Bulgaria, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland,

25、 Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and the United Kingdom. DD CEN/TS 15731:2008CEN/TS 15731:2008 (E) 5 Introduction The end-use value of wheat is determined by a number of properties that are us

26、eful in the manufacture of baked products such as bread, rusks, biscuits, etc. 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

27、to biaxial extension (producing a dough bubble) at adapted hydration by 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 rupture

28、provides information on: resistance of the dough to deformation, or its strength (stiffness). It is expressed by the maximum pressure parameter “T”; extensibility or the possibility of inflating the dough to form a bubble. It is expressed by the parameters of extensibility “A” or swelling “Ex”; elas

29、ticity of the dough during biaxial extension. It is expressed by the elasticity index “Iec”; energy required to deform the dough bubble until it bursts, which is proportional to the area of the alveogram (sum of the pressures throughout the deformation process). It is expressed by the parameter “Fb”

30、. It is generally accepted that the tenacity “T” and the extensibility “A” shall exceed a minimum level which can be varied, depending on the particular end use to which the flour is to be put. The T/A ratio is a measurement of the balance between tenacity and extensibility. Alveographs are commonly

31、 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 for the alveographic criteria (W, P and L) complying with

32、the proportional laws of blending; Alveographs are used both on the upstream side of the industry for marketing, selecting and assessing the different varieties and on the downstream side throughout the baking industries (see Bibliography). DD CEN/TS 15731:2008CEN/TS 15731:2008 (E) 6 1 Scope This do

33、cument specifies a method that uses an alveograph to determine the rheological properties of different types of dough at adapted hydration obtained from “soft” to “hard” wheat flour (Triticum aestivum L.) produced by industrial milling or laboratory test milling. It describes the alveograph test and

34、 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 itself, including the break system involving three fluted rollers, reduction of par

35、ticle size between two smooth rollers and the use of a centrifugal sieving machine to grade the products (see Clause 8). 2 Normative references The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated

36、 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 7700-1, Check of the calibration of moisture meters - Part 1: Moisture meters for cereals 3 Principle

37、 The principle of measurement involves the evaluation, during deformation, of the behaviour of dough obtained from a mixture of different types of flour and salt water. A dough disk is subjected to a constant air flow; at first it withstands the pressure, then it swells into a bubble, according to i

38、ts extensibility and ruptures. The change in the dough is measured and recorded in the form of a curve called an alveogram. DD CEN/TS 15731:2008CEN/TS 15731:2008 (E) 7 4 Reagents Unless otherwise specified, use only reagents of recognised analytical quality, and distilled or demineralised water, or

39、water of equivalent purity. 4.1 Sodium chloride solution, obtained by dissolving (25 0,2) g of sodium chloride in distilled water and then making it up to 1 000 ml. This solution shall not be stored for more than 15 days and its temperature shall be (20 2)C when used. 4.2 Refined vegetable oil, low

40、in polyunsaturates such as peanut oil. It is possible to use olive oil if its acid index value is less than 0,4 (determined according to EN ISO 660). Store in a dark place in a closed container and replace regularly (every 3 months). Alternatively, liquid paraffin (also known as “vaseline oil”), wit

41、h an acid index value less than or equal to 0,05 and the lowest possible viscosity (maximum 60 mPa.s (60 cP) at 20 C). 4.3 Cold degreasing agent - optimum safety.1)5 Apparatus Common laboratory equipment, including the following: 5.1 Mechanical cleaner fitted with sieves for wheat cleaning, in accor

42、dance with the manufacturers requirements. 5.2 Conical or riffle sample divider. 5.3 Analytical balance accurate to 0,01 g. 5.4 50 ml glass burette graduated in 0,1 ml increments, stand-mounted. 5.5 Rotary blender2)for grain conditioning and flour homogenisation. It includes the following devices: 5

43、.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 homogenisation). 5.5.3 Several wide-necked 2-litre plastic flasks. 5.6 Test mill3)(laboratory mill) manually operated (see Annex A). 1)ITECMA “Securcle

44、an ER” is an example of a suitable product available commercially. This information is given for the convenience of users of this Technical Specification and does not constitute an endorsement by CEN of this this product. 2) The Chopin MR 2-litre rotary mixer is an example of a suitable product avai

45、lable commercially. This information is given for the convenience of users of this Technical Specification and does not constitute an endorsement by CEN of this this product. 3) The Chopin-Dubois CD1 test mill is an example of a suitable product available commercially. This information is given for

46、the convenience of users of this Technical Specification and does not constitute an endorsement by CEN of this this product. DD CEN/TS 15731:2008CEN/TS 15731:2008 (E) 8 5.7 Complete alveograph system (the specifications and characteristics for some of the accessories are given in Table 1) and includ

47、e the following devices: 5.7.1 Kneading machine (see Figure 1 a) for models MA 82, MA 87 and MA 95 and Figures 2 a and 3 a for model NG, with accurate temperature control, for dough sample preparation. 5.7.2 Hydraulic Manometeror Alveolink (See Figure 1 b) for models MA 82, MA 87 and MA 95 and Figur

48、es 2 b and 3 b for model NG, for recording the pressure curve. 5.7.3 Alveograph4)(see Figure 1 c) for models MA 82, MA 87 and MA 95 and Figures 2 c and 3 c)for the NG model, with accurate temperature control, for test piece biaxial deformation of the dough pieces. It has two rest chambers, each cont

49、aining five plates on which the dough test pieces can be arranged prior to deformation. 5.8 Burette, capacity 160 ml, graduated in percentages of 0,1% of moisture content5). 5.9 Timer6). 5.10 Set of planimetric scales 7). 5.11 System for recording the test environment conditions (temperature and relative air humidity) as specified in 8.1 and 9.1. 5.12 Class A 1000 ml volumetric flask (Grade A). 5.13 Pipette (25ml) graduated in 0,1 ml increments. 4)This part of ISO 5530 was based on the CHOPIN alveograph, which is the only device o