BS 4317-20-1999 Methods of test for cereals and pulses - Determination of water absorption of flour and rheological properties of doughs using a farinograph《谷物和豆类的试验方法 用淀粉测定记录仪测定面粉.pdf

1、| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | BRITISH STANDARD BS 4317-20:1999 ICS 67.06

2、0 NO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAW Methods of test for Cereals and pulses Part 20: Determination of water absorption of flour and rheological properties of doughs using a farinographThis British Standard, having been prepared under the direction of the Consumer

3、Products and Services Sector Committee, was published under the authority of the Standards Committee and comes into effect on 15 December 1999 BSI 12-1999 The following BSI references relate to the work on this standard: Committee reference AW/4 Draft for comment 95/502231 DC ISBN 0 580 33054 0 BS 4

4、317-20:1999 Amendments issued since publication Amd. No. Date Comments Committees responsible for this British Standard The preparation of this British Standard was entrusted to Technical Committee AW/4, Cereals and pulses, upon which the following bodies were represented: Agricultural Engineers Ass

5、ociation Association of Public Analysts Campden and Chorleywood Food Research Association Grain and Feed Trade Association Home Grown Cereals Authority Institute of Brewing Institute of Food Science and Technology Intervention Board Maltsters Association of Great Britain Ministry of Agriculture, Fis

6、heries and Food NABIM National Farmers Union Natural Resources Institute United Kingdom Agricultural Supply Trade Association Ltd.BS 4317-20:1999 BSI 12-1999 i Contents Page Committees responsible Inside front cover Foreword ii 1 Scope 1 2 Terms and definitions 1 3 Principle 1 4 Reagents 1 5 Apparat

7、us 1 6 Procedure 1 7 Expression of results 2 Annex A (informative) Repeatability and reproducibility 3 Figure 1 Farinogram 2 Table A.1 Repeatability: limits of result differences 3 Table A.2 Reproducibility: limits of result differences 3 Table A.3 Water absorption 3 Table A.4 Results of interlabora

8、tory tests for water absorption 4 Table A.5 Development time 4 Table A.6 Results of interlaboratory tests for development time 4 Table A.7 Stability 5 Table A.8 Results of interlaboratory tests for stability 5 Table A.9 Degree of softening 6 Table A.10 Results of interlaboratory tests for degree of

9、softening 6ii BSI 12-1999 BS 4317-20:1999 Foreword This part of BS 4317 has been prepared by Technical Committee AW/4, Cereals and pulses. It supersedes BS 4317-20:1989, which is withdrawn. This British Standard is derived from ICC Standard Method No. 115/1, published by the International Associatio

10、n for Cereal Science and Technology. A British Standard does not purport to include all the necessary provisions of a contract. Users of British Standards are responsible for their correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations. Summ

11、ary of pages This document comprises a front cover, an inside front cover, pages i and ii, pages 1 to 6, an inside back cover and a back cover. The BSI copyright notice displayed in this document indicates when the document was last issued. BSI 12-1999 1 BS 4317-20:1999 1) This part of BS 4317 has b

12、een prepared based on work with the Brabender Farinograph. This information is given for the convenience of users of this part of BS 4317 and does not constitute an endorsement by BSI of this product. 1 Scope This part of BS 4317 specifies a method, using a farinograph 1) , for determination of the

13、water absorption of flours and the mixing behaviour of doughs made from these. The method is applicable to white, brown and wholemeal wheat flours. Details of an interlaboratory trial on the repeatability and reproducibility of results gained using the method specified in this British Standard are g

14、iven in annex A. 2 Terms and definitions For the purposes of this part of BS 4317, the following terms and definitions apply. 2.1 consistency resistance of a dough to being mixed in a farinograph at a specified constant speed (expressed in farinograph units, BU) 2.2 water absorption (of flour) volum

15、e percentage of water in a water/flour mixture required to produce a dough with a consistency of 600 BU 3 Principle A farinograph measures and records the consistency of a dough. The consistency is adjusted to 600 BU and the water absorption calculated. The water absorption is used to determine the

16、mixing curve, which is a guide to the strength of the flour. 4 Reagents 4.1 Distilled water or deionized water or water of equivalent purity. 5 Apparatus NOTE All measuring equipment should be calibrated. 5.1 Farinograph, with burette and constant temperature water circulating tank. For a 300 g bowl

17、 the burette shall be graduated from 135 ml to 225 ml with an accuracy of 0.6 ml and for a 50 g bowl from 22.5 ml to 37.5 ml with an accuracy of 0.2 ml. The burette shall provide readings in percentage water added (i.e. 0 % to 75 %). 5.2 Balance, at least able to weigh 300 g with an accuracy of 0.01

18、 g. 5.3 Plastics scraper. 5.4 Thermometer, graduated in intervals of 0.18C. 6 Procedure 6.1 Operational requirements of the farinograph The farinograph shall be level. If the bubble in the spirit level attached to the base plate is not centred, adjust the foot screws accordingly. The time to flow fr

19、om 0 ml to 225 ml or 0 ml to 37.5 ml for 300 g and 50 g bowl burettes respectively shall be 20 s 2s . Turn on the thermostat and circulate the water until the required temperature is reached prior to using the farinograph. (Warm up for a period of 1 h before conducting any test measurements.) Before

20、 and during use, check the temperature of the thermostat and mixing bowl, the latter in the hole provided for this purpose. Both temperatures shall be 30.08C 0.58C. Lubricate the mixer with a drop of water between its back plate and each of the blades. Check for zero deflection of the pointer with t

21、he motor running at approximately 63 r/min (clean the bowl and recheck if required). If zero deflection is not obtained and the bowl has been thoroughly cleaned including the area behind the blades, adjust the zero point to obtain zero deflection of the pointer with the motor running at approximatel

22、y 63 r/min. Adjust the position of the pen to obtain identical readings from the pointer and pen. Ensure that the chart paper is correctly aligned on the sprockets. NOTE When the upper lever arm is moved the pen should follow the arc on the chart paper. 6.2 Dough preparation Allow the flour to equil

23、ibrate to 25.08C 5.08C. Run the bowl empty for 1 min and ensure that the pen centres on the zero line. Before carrying out any tests mix a scrap dough. Place 300.0 g or 50.0 g of flour in the bowl as appropriate for the size of bowl. Close the lid to engage the safety switch. Set the pen on the char

24、t paper on a 9 min line. Start mixing the dry flour with the motor running at approximately 63 r/min. The pen shall read 20 BU or less. Fill the burette including the tip with water at 30.08C 2.08C. As the pen crosses the 0 min line, start adding water from the burette through the front end of the r

25、ight hand slot in the lid. Add a volume of water expected to bring the curve to a consistency of 600 BU. When the dough forms, carefully use the plastics scraper to push any flour particles or dough adhering to the mixing bowl walls down into the mixture.2 BSI 12-1999 BS 4317-20:1999 Figure 1 Farino

26、gram If the consistency is too high add more water to centre the curve on 600 BU 20 BU. (If the water is not added in a single titration, the sample shall not be used to determine the farinograph characteristics.) NOTE Remove the dough and clean the bowl as follows. Stop the mixer, set the pen away

27、from the paper, add a little flour and mix for a short time to stiffen the dough. Take care to avoid exceeding a consistency of about 800 BU. Remove the dough, clean the bowl and blades thoroughly with warm water and dry with a clean cloth. Make further mixing(s) if required until the correct water

28、addition is made within 30 s and continue mixing for at least 12 min after the curve first shows signs of weakening or until the required features of the curve are revealed. The maximum band width obtained during any test shall lie in the range 70 BU to 90 BU. If the band width falls beyond this ran

29、ge, adjust the damping accordingly and repeat the test. 7 Expression of results 7.1 Water absorption Read the water absorption (%) directly from the burette. 7.2 Farinogram characteristics Measure the farinogram relative to the line on which the curve centres (e.g. if the curve centres at 610 BU, ma

30、ke the measurement along this line). 7.3 Development time Report the development time (the time from the start of mixing to the point on the curve immediately before the first signs of weakening) to the nearest 0.5 min. If two peaks are observed, use the second peak to measure development time. NOTE

31、 See example farinogram in Figure 1. 7.4 Stability Report the stability (the difference in time between the point where the top of the curve first intercepts the line equivalent to a consistency of 600 BU and the point where the top of the curve leaves this line) to the nearest 0.5 min. NOTE See exa

32、mple farinogram in Figure 1. 7.5 Degree of softening Report the degree of softening (the difference in height between the centre of the curve immediately before the first signs of weakening and the centre of the curve 12 min afterwards) to the nearest 5 BU. NOTE See example farinogram in Figure 1.BS

33、 4317-20:1999 BSI 12-1999 3 Annex A (informative) Repeatability and reproducibility A.1 Repeatability r Values for the difference between two independent single test results obtained by the method specified in this British Standard, from examination of identical test material in the same laboratory

34、by the same operator using the same equipment and within a short interval of time, are given in Table A.1. Table A.1 Repeatability: limits of result differences Measurement Difference Water absorption 0.5 % Development time 0.5 min Stability 1.0 min Degree of softening 20 BU A.2 Reproducibility R Va

35、lues for the difference between two single test results obtained by the method specified in this British Standard, from examination of identical test material in different laboratories with different operators using different equipment, are given in Table A.2. Table A.2 Reproducibility: limits of re

36、sult differences Measurement Difference Water absorption 1.6 % Stability 2.0 min Development time 1.0 min Degree of softening 45 BU A.3 Water absorption The results of interlaboratory trials to determine water absorption are given in Table A.3. Table A.3 Water absorption Measurement Sample A Sample

37、B Sample C Total Number of laboratories 12 12 12 12 Number of results 24 24 24 72 Number of laboratories retained after deletion of outliers 12 12 12 12 Number of accepted results 24 24 24 72 Mean 66.2 56.8 59.4 60.8 Repeatability standard deviation S(r) 0.22 0.18 0.15 0.19 Repeatability coefficient

38、 of variation CV(r) % 0.34 0.32 0.26 0.31 Reproducibility standard deviation S(R) 0.81 0.46 0.39 0.55 Reproducibility coefficient of variation CV(R) % 1.23 0.80 0.65 0.91 Repeatability r 95 % 2.833 S(r) 0.63 0.52 0.44 0.53 Reproducibility R 95 % 2.833 S(R) 2.30 1.29 1.09 1.564 BSI 12-1999 BS 4317-20

39、:1999 Annex A The reported results of the interlaboratory trials for water absorption are given in Table A.4 (expressed as percentage of flour mass). No outliers or stragglers were identified. Table A.4 Results of interlaboratory tests for water absorption Laboratory no. Sample A Sample B Sample C 1

40、 66.9 66.9 57.3 57.3 59.8 59.8 2 65.8 66.0 56.5 56.4 59.4 59.3 3 66.1 65.8 57.0 56.5 59.2 59.1 4 67.0 66.6 56.7 57.0 59.0 59.4 7 66.4 66.3 56.9 56.6 59.7 60.0 9 64.8 65.5 56.5 56.0 58.8 59.0 10 66.2 66.0 57.2 57.2 59.7 59.7 11 66.9 67.0 56.5 56.6 59.5 59.5 12 66.0 66.0 57.0 57.0 59.0 59.5 13 64.5 64

41、.2 56.0 56.3 58.8 58.8 14 66.3 66.8 57.1 57.2 59.7 59.7 15 67.0 67.1 57.5 57.65 59.8 59.9 A.4 Development time The results of interlaboratory trials to determine development time are given in Table A.5. Table A.5 Development time Measurement Sample A Sample B Sample C Total Number of laboratories 12

42、 12 12 12 Number of results 24 24 24 72 Number of laboratories retained after deletion of outliers 12 12 12 12 Number of accepted results 24 24 24 72 Mean 3.4 1.8 2.1 2.4 Repeatability standard deviation S(r) 0.28 0.11 0.17 0.19 Repeatability coefficient of variation CV(r) % 8.18 6.19 7.93 7.92 Repr

43、oducibility standard deviation S(R) 0.46 0.13 0.33 0.30 Reproducibility coefficient of variation CV(R) % 13.43 6.80 15.29 12.27 Repeatability r 95 % 2.833 S(r) 0.79 0.32 0.48 0.53 Reproducibility R 95 % 2.833 S(R) 1.30 0.37 0.92 0.86 The reported results are given in Table A.6 (expressed in minutes)

44、. No outliers or stragglers were identified. Table A.6 Results of interlaboratory tests for development time Laboratory no. Sample A Sample B Sample C 1 3.0 3.0 2.0 2.0 2.0 2.0 2 3.5 3.5 2.0 2.0 2.5 2.5 3 3.5 3.5 2.0 2.0 2.0 2.0 4 4.0 4.5 1.5 2.0 2.0 2.0 7 3.5 3.5 1.75 1.75 2.25 2.0 9 3.0 3.5 1.75 1

45、.75 2.0 2.0 10 3.0 3.0 1.75 1.75 1.75 2.0 11 3.0 3.5 2.0 2.0 2.0 2.5 12 4.0 3.75 2.0 2.0 3.0 2.5 13 3.75 3.0 1.5 1.25 2.0 1.75 14 2.5 3.0 1.75 1.75 1.75 1.75 15 4.0 3.5 2.0 2.0 2.5 2.5 BSI 12-1999 5 Annex A BS 4317-20:1999 A.5 Stability The results of interlaboratory trials to determine stability ar

46、e given in Table A.7. Table A.7 Stability Measurement Sample A Sample B Sample C Total Number of laboratories 12 12 12 12 Number of results 24 24 24 72 Number of laboratories retained after deletion of outliers 12 12 12 12 Number of accepted results 24 24 24 72 Mean 6.4 1.7 3.6 3.9 Repeatability sta

47、ndard deviation S(r) 0.56 0.15 0.28 0.33 Repeatability coefficient of variation CV(r) % 8.78 9.13 7.56 8.46 Reproducibility standard deviation S(R) 0.93 0.22 1.07 0.74 Reproducibility coefficient of variation CV(R) % 14.44 12.94 29.5 18.89 Repeatability r 95 % 2.833 S(r) 1.60 0.43 0.78 0.94 Reproduc

48、ibility R 95 % 2.833 S(R) 2.62 0.61 3.04 2.09 The reported results are given in Table A.8 (expressed in minutes). Stragglers are marked * and are excluded from the final statistical analysis. Table A.8 Results of interlaboratory tests for stability Laboratory no. Sample A Sample B Sample C 1 5.0 6.0

49、 1.5 2.0 4.0 4.0 2 7.0 6.5 1.5 1.5 4.0 3.5 3 7.0 5.0 2.0 2.0 3.5 3.0 4 7.0 7.0 1.5 2.0 3.5 3.0 7 6.0 6.25 1.75 1.75 3.5 3.0 9 5.5 6.0 1.5 1.5 2.5 2.5 10 5.5 5.5 1.5 1.5 2.5 2.25 11 6.0 6.0 2.0 2.0 4.0 4.5 12 8.5 8.5* 1.5 1.5 6.5 6.0 13 7.5 6.25 1.75 1.5 3.5 3.0 14 6.5 7.0 1.75 1.75 2.5 3.0 15 6.5 6.0 1.5 1.5 4.5 4.56 BSI 12-1999 BS 4317-20:1999 Annex A A.6 Degree of softening The results of interlaboratory trials to determine the degree of softening are given in Table A.9. Table A.9 Degree of softening Measurem