DIN EN ISO 7973-2016 Cereals and milled cereal products - Determination of the viscosity of flour - Method using an amylograph (ISO 7973 1992) German version EN ISO 7973 2015《谷物和精制.pdf

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1、March 2016 English price group 11No 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!%N(T“2430549www.din.deDIN E

2、N ISO 7973Cereals and milled cereal products Determination of the viscosity of flour Method using an amylograph (ISO 7973:1992);English version EN ISO 7973:2015,English translation of DIN EN ISO 7973:2016-03Getreide und gemahlene Getreideerzeugnisse Bestimmung der Viskositt von Mehl Amylograph-Verfa

3、hren (ISO 7973:1992);Englische Fassung EN ISO 7973:2015,Englische bersetzung von DIN EN ISO 7973:2016-03Crales et produits de mouture des crales Dtermination de la viscosit de la farine Mthode utilisant un amylographe (ISO 7973:1992);Version anglaise EN ISO 7973:2015,Traduction anglaise de DIN EN IS

4、O 7973:2016-03www.beuth.deDocument comprises 14 pagesDTranslation by DIN-Sprachendienst.In case of doubt, the German-language original shall be considered authoritative.03.16 DIN EN ISO 7973:2016-03 2 A comma is used as the decimal marker. National foreword This document (ISO 7973:1992) has been pre

5、pared by Technical Committee ISO/TC 34 “Food products” (Secretariat: AFNOR, France), Subcommittee SC 4 “Cereals and pulses” (Secretariat: SAC, China) and has been taken over as EN ISO 7973:2015 by Technical Committee CEN/TC 338 “Cereal and cereal products” (Secretariat: AFNOR, France). The responsib

6、le German body involved in its preparation was DIN-Normenausschuss Lebensmittel und landwirtschaftliche Produkte (DIN Standards Committee Food and Agricultural Products), Working Committee NA 057-05-06 AA Getreide und Getreideerzeugnisse. The DIN Standards corresponding to the International Standard

7、s referred to in this document are as follows: ISO 712 DIN EN ISO 712 ISO 3093 DIN EN ISO 3093 National Annex NA (informative) Bibliography DIN EN ISO 712, Cereals and cereal products Determination of moisture content Reference method DIN EN ISO 3093, Wheat, rye and their flours, durum wheat and dur

8、um wheat semolina Determination of the falling number according to Hagberg-Perten EUROPEAN STANDARD NORME EUROPENNE EUROPISCHE NORM EN ISO 7973 December 2015 ICS 67.060 English Version Cereals and milled cereal products - Determination of the viscosity of flour - Method using an amylograph (ISO 7973

9、:1992) Crales et produits de mouture des crales - Dtermination de la viscosit de la farine - Mthode utilisant un amylographe (ISO 7973:1992) Getreide und gemahlene Getreideerzeugnisse - Bestimmung der Viskositt von Mehl - Amylograph- Verfahren (ISO 7973:1992) This European Standard was approved by C

10、EN on 30 November 2015. 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 alteration. Up-to-date lists and bibliographical references concerning such national standa

11、rds may be obtained on application to the CEN-CENELEC Management Centre or to any CEN member. 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 not

12、ified to the CEN-CENELEC Management Centre has the same status as the official versions. CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, I

13、celand, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and United Kingdom. EUROPEAN COMMITTEE FOR STANDARDIZATION C O MIT E U R O P EN D E N O RMA L I S A T IO N EU ROP IS CH ES K OMITEE F R

14、 NORMU N G 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 7973:2015 E DIN EN ISO 7973:2016-03 EN ISO 7973:2015 (E) 2Contents Page European foreword . 3 Fore

15、word 4 1 Scope 5 2 Normative references 5 3 Definition 5 4 Principle 5 5 Reagent . 5 6 Apparatus 5 7 Sampling . 6 8 Procedure . 6 9 Calculation 7 10 Precision . 9 11 Test report 9 Annex A (informative) Calibration of the amylograph . 10 Annex B (informative) Results of inter-laboratory test 11 Annex

16、 C (informative) Bibliography 12 European foreword The text of ISO 7973:1992 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 7973:2015 by Technical Committee CEN/TC 338 “Cereal and cereal

17、 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 endorsement, at the latest by June 2016, and conflicting national standards shall be withdrawn at the latest by June 2016. A

18、ttention 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 identifying any or all such patent rights. According to the CEN-CENELEC Internal Regulations, the national standards organizations

19、 of the following countries are bound to implement this European Standard: 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, N

20、etherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the United Kingdom. Endorsement notice The text of ISO 7973:1992 has been approved by CEN as EN ISO 7973:2015 without any modification. DIN EN ISO 7973:2016-03 EN ISO 7973:2015 (E) 3 Foreword IS

21、O (the International Organization 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. Esch member body interested in a subject for which a technical co

22、mmittee has been established has the right to be represented on that committee. International organizations, govern- mental and non-governmental, in liaison with ISO, also take patt in the work. ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of elect

23、rotechnical standardization. Draft International Standards adopted by the technical committees are circulated to the member bodies for voting. Publication as an Inter- national Standard requires approval by at least 75 % of the member bodies casting a vote. International Standard ISO 7973 was prepar

24、ed by Technical Committee ISO/TC 34, Agricultural food products, Sub-Committee SC 4, Cereals and pulses. This International Standard takes into account Standard No. 126 of the International Association for Cereal Science and Technology (ICC). Annex A forms an integral part of this International Stan

25、dard. Annexes B and C are for information only. DIN EN ISO 7973:2016-03 EN ISO 7973:2015 (E) 4 1 Scope This International Standard specifies a method using an amylograph for determining the viscosity of a Suspension of flour in watet-, in which the starch is gelatinized by heating, in Order io asses

26、s the con- ditions of gelatinization of the flour and so judge whether there is any alpha-amylase activity. This method is applicable to wheat and rye flour and also to wheat and rye grain. NOTES 1 This International Standard has been prepared on the basis of the Brabender-type amylograph. 2 This me

27、thod applies strictly to an amylograph and not to a viscograph, since an amylograph possesses the fol- lowing characteristics: - it is possible to Change the torque-measuring head; - the heating coils are located around the bowl of the apparatus and at the bottom; - there is no cooling rod for lower

28、ing the gel tempera- ture. 2 Normative references The following Standards contain provisions which, through reference in this text, constitute provisions of this International Standard. At the time of publi- cation, the editions indicated were valid. All stan- dards are subject to revision, and Part

29、ies to agreements based on this International Standard are encouraged to investigate the possibility of ap- plying the most recent editions of the Standards in- dicated below. Members of IEC and ISO maintain registers of currently valid Internaiional Standards. ISO 712:1985, Cereals and cereal produ

30、cts - Deter- mination of moisture content (Routine reference method). ISO 3093:1982, Cereals - Determination of falling number. 3 Definition For the purposes of this International Standard, the following definition applies. 3.1 amylograph viscosity: Maximum viscosity reached by a Suspension of flour

31、 and water which is gelatinized by heating under the conditions set out in this International Standard. lt is expressed as an arbitrary unit: amylograph unit (AU) n 4 Principle Preparation of a Suspension of flour in watet-, fol- lowed by recording of the viscosity of the suspen- sion which is heate

32、d at a constant rate from 30 C to the temperature corresponding to the moment at which viscosity Starts to decrease, having reached its maximum (approximately 95 “C). The increase in viscosity due to gelatinization of the starch is dependent upon the increase in tempera- ture, the mechanical action

33、of stirring and the ac- tivity of alpha-amylase already present or added to the flour. 5 Reagent 5.1 Distillled water, or water of equivalent purity. 6 Apparatus Usual laboratory equipment and, in particular, the following. DIN EN ISO 7973:2016-03 EN ISO 7973:2015 (E) 5 6.1 Amylograph, having the fo

34、llowing character- istics: Speed of rotation of the spindle (75 + 1) rev/min Torque exerted per amylograph unit (AU), using a stan- dard measuring (6,86 i.e. capable of grinding a product of moisture content up to 30 % (m/m) and with adjustment to obtain a meal meeting the requirements of table 1. T

35、able 1 - Particle size requirements Mesh opening of sieve Pm Meal passing through the sieve % 710 100 500 95 to 100 210 to 200 80 or less 7 Sampling It is important that the laboratory receive a Sample which is truly representative and has not been damaged or changed during transport and storage. Sa

36、mpling is not part of the method specified in this International Standard. Recommended sampling methods are given in ISO 950 (for grains) and ISO 2170 (for milled products). 8 Procedure 8.1 Preparation of test Sample 8.1 .l Flour Use the laboratory Sample as provided, after thor- ough mixing, taking

37、 test samples as required. 8.1.2 Grain Remove dust and coarse impurities from the lab- oratory Sample and then take approximately 300 g of grain. Grind the Sample carefully in the mill (6.6), avoiding heating or overloading. Continue grinding for 30 s to 40 s alter the last of the Sample has been fe

38、d into the mill. Bran particles up to 1 % remaining on the Screen may be discarded. Thoroughly mix the milled product. 8.2 Preliminary operations 8.2.1 Determination of the moisture content of the test Sample Determine the moisture content of the test Sample (8.1) in accordance with ISO 712. 8.2.2 A

39、djustment of the amylograph and no-load test Manually adjust the starting temperature of the temperature regulator to 30 OC, with the clutch in the neutral Position. Fill the pen with ink. Place the spindle in the bowl, connect the spindle to the shaft and lower the amylograph head into Position. St

40、art the motor and check that the pen moves over the baseline of the recording Paper. If necessary, adjust the Position of the pen on its arm. Stop the motor, disconnect the spindle, lift and turn the head of the apparatus. Remove the spindle. 1) Kamas Slago 200 A and Falling Number type KT 120 mills

41、 are examples of suitable commercially available products. This information is given for the convenience of users of this International Standard and does not constitute an endorse- ment by ISO of the products named. Equivalent products may be used if they tan be shown to lead to the same results. DI

42、N EN ISO 7973:2016-03 EN ISO 7973:2015 (E) 6 CAUTION - Refer to annex A for the calibration of the amylograph. Particular care shall be taken when adjusting the contact thermometer as its Position has a marked influence on the results. 8.3 Test Portion 8.3.1 For flour Weigh, to the nearest 0,l g, th

43、e equivalent of 80,O g of flour with a moisture content of 14,0 % (m/m). This mass, m, in grams, is given in table 2 as a function of moisture content. 8.3.2 For grain Adjust the mass of the test Portion so that 90,O g of milled product corresponds to a moisture content of 14,0 % (m/m). This mass, m

44、, in grams, is also given in table 2 as a function of moisture content. 8.4 Preparation of Suspension 8.4.1 Fill the burette (6.3) with distilled water up to the Zero mark. 8.4.2 Place the test Portion in the beaker (6.4) and add 100 ml of water from the burette. Mix with the spatula (6.5) for appro

45、ximately 20 s in Order to ob- tain a uniform Suspension. NOTE 3 A longer mixing time may be necessary for rye flour. While continuing to stir, gradually add the water (in four stages) until there are approximately 100 ml remaining in the burette and check that the suspen- sion is free from lumps and

46、 there is as little foaming as possible, then pour the Suspension into the amylograph bowl. 8.4.3 Using the spatula, scrape up any residue of Suspension which might be sticking to the sides and bottom of the beaker and dilute with half the water remaining in the burette. Pour all of this Suspension

47、into the amylograph bowl. Pour the remaining water into the beaker to rinse it and collect a quantity of rinsing Solution in the amylograph bowl, such that the total mass of the Suspension is 530,O g is the moisture content of the Sample, ex- pressed as a percentage by mass; m is the mass, in grams,

48、 of a test por- tion of moisture content 14 % ( mr = 80 g or mr = 90 g). 9.2 Determination of temperature at maximum viscosity The temperature 6, at maximum viscosity, ex- pressed in degrees Celsius, is given by the formula 6 = 30,o + (tf - 30,o) x a/b is the temperature, in degrees Celsius, read from the thermometer at the end of the test (approximately 95 “C); a is the length, in centimetres, of the re- cording from the mark made at the Start of t