BS 4317-22-1989 Methods of test for cereals and pulses - Determination of water absorption of flour and rheological properties of doughs using a valorigraph《谷物和豆类试验方法 第22部分 使用稠度记录测.pdf

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1、BRITISH STANDARD BS4317-22: 1989 ISO5530-3: 1988 Methods of test for Cereals and pulses Part 22: Determination of water absorption of flour and rheological properties of doughs using a valorigraph UDC 664.641.12:664.653.8.014:543.812BS4317-22:1989 This British Standard, having been prepared under th

2、e directionof the Food and Agriculture Standards Policy Committee, was published underthe authority of the BoardofBSI and comes into effect on 29 September1989 BSI08-1999 The following BSI references relate to the work on this standard: Committee reference FAC/4 Draft for comment83/54855 DC ISBN 0 5

3、80 17644 4 Committees responsible for this British Standard The preparation of this British Standard was entrusted by the Food and Agriculture Standards Policy Committee (FAC/-) to Technical Committee FAC/4, upon which the following bodies were represented: AFRC Institute of Engineering Research Agr

4、icultural Engineers Association Association of Public Analysts British Edible Pulse Association Department of Trade and Industry (Laboratory of the Government Chemist) Flour Milling and Baking Research Association Food and Drink Federation Grain and Feed Trade Association Home Grown Cereals Authorit

5、y Institute of Brewing Institute of Food Science and Technology Intervention Board for Agricultural Produce Ministry of Agriculture, Fisheries and Food NABIM National Association of Commodity Cargo Superintendents and Surveyors National Farmers Union Overseas Development Natural Resources Institute

6、Society of Chemical Industry United Kingdom Agricultural Supply Trade Association Ltd. Amendments issued since publication Amd. No. Date of issue CommentsBS4317-22:1989 BSI 08-1999 i Contents Page Committees responsible Inside front cover National foreword ii 1 Scope 1 2 Normative references 1 3 Def

7、initions 1 4 Principle 1 5 Reagent 1 6 Apparatus 1 7 Sampling 1 8 Procedure 1 9 Expression of results 2 10 Test report 4 Annex A (informative) Description of the valorigraph 5 Figure 1 Representative valorigram showing the commonly measured indices 4 Figure A.1 Diagram of valorigraph unit 5 Table 1

8、Mass of flour, in grams, equivalent to50g, at a moisture content of14% (m/m) 3 Table 2 Precision of valorigraph measurements 4 Publications referred to Inside back coverBS4317-22:1989 ii BSI 08-1999 National foreword This Part of BS4317 has been prepared under the direction of the Food and Agricultu

9、re Standards Policy Committee. It is identical with ISO5530-3:1988 “Wheat flour Physical characteristics of doughs Part3: Determination of water absorption and rheological properties using a valorigraph” published by the International Organization for Standardization (ISO), and in the preparation of

10、 which the United Kingdom played a full part. Additional information. With reference to clause5, water complying with grade3 of BS3978 “Specification for water for laboratory use” is suitable. A British Standard does not purport to include all the necessary provisions of a contract. Users of British

11、 Standards are responsible for their correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations. Cross-references International Standard Corresponding British Standard ISO712:1985 BS4317 Methods of test for cereals and pulses Part3:1987 Determin

12、ation of moisture content of cereals and cereal products (routine method) (Identical) ISO2170:1980 BS5333:1981 Methods for sampling cereals and pulses (as milled products) (Identical) Summary of pages This document comprises a front cover, an inside front cover, pagesi andii, pages1 to6, an inside b

13、ack cover and a back cover. This standard has been updated (see copyright date) and may have had amendments incorporated. This will be indicated in the amendment table on the inside front cover.BS4317-22:1989 BSI 08-1999 1 1 Scope This part of ISO5530 specifies a method, using a valorigraph 1) , for

14、 the determination of the water absorption of flours and the mixing behaviour of doughs made from them. The method is applicable to flour from wheat (Triticum aestivum Linnaeus). 2 Normative references The following standards contain provisions which, through reference in this text, constitute provi

15、sions of this part of ISO5530. At the time of publication, the editions indicated were valid. All standards are subject to revision, and parties to agreements based on this part of ISO5530 are encouraged to investigate the possibility of applying the most recent editions of the standards listed belo

16、w. Members of IEC and ISO maintain registers of currently valid International Standards. ISO712:1985, Cereals and cereal products Determination of moisture content (Routinereference method). ISO2170:1980, Cereals and pulses Sampling of milled products. 3 Definitions For the purposes of this part of

17、ISO5530, the following definitions apply. 3.1 consistency the resistance, expressed in arbitrary units (valorigraph units, VU), of a dough to being mixed in the valorigraph at a specified constant speed 3.2 water absorption (of flour) the volume of water, expressed in millilitres per100g of flour at

18、14% (m/m) moisture content, required to produce a dough with a maximum consistency of500VU, under the operating conditions specified in this part of ISO5530 4 Principle Measurement and recording, by means of a valorigraph, of the consistency of a dough as it is formed from flour and water, as it is

19、developed, and as it is broken down. NOTEThe maximum consistency of the dough is adjusted to a fixed value by adapting the quantity of water added. The correct water addition, which is called the water absorption, is used to obtain a complete mixing curve, the various features of which are a guide t

20、o the strength of the flour. 5 Reagent Distilled water, or water of equivalent purity. 6 Apparatus Usual laboratory equipment and, in particular, the following. 6.1 Valorigraph (see Annex A). 6.1.1 Operating characteristics Slow blade rotational frequency: (64 2)min 1 The ratio of the rotational fre

21、quencies of the mixing blades shall be1,50 0,01. Deflection of the recorder pen, when the lever arm is loaded, at the appropriate position (75mm from the pivot), with the calibrating weight (900g, accessory of the instrument), with the mixing blades rotating in the empty bowl:(500 10) VU Chart speed

22、: (1,00 0,03)cm/min 6.1.2 Burettes burette graduated from25ml to35ml in0,1ml divisions, and burette graduated from32ml to42ml in0,1ml divisions. The time to flow from0ml to35ml or0ml to42ml respectively shall be not more than20s. 6.2 Balance, accurate to0,1g. 6.3 Plastic spatula 6.4 Water-bath, capa

23、ble of being controlled at a temperature of (31 1) C. 7 Sampling Carry out sampling by the method specified in ISO2170. 8 Procedure 8.1 Determination of the moisture content of the flour Determine the moisture content of the flour using the method specified in ISO712. 1) This part of ISO5530 has bee

24、n drawn up on the basis of the Labor-MIM Valorigraph. This information is given for the convenience of users of this part of ISO5530 and does not constitute an endorsement by ISO of this product.BS4317-22:1989 2 BSI 08-1999 8.2 Preparation of sample and apparatus 8.2.1 If necessary, bring the flour

25、to a temperature of (25 5) C. Fill the flask of the valorigraph with water. Switch on the preheating and the thermostatically controlled heating. When the air temperature has reached28 C, switch off the preheating. Start a flow of tap water through the cooling tubes of the valorigraph. Before and du

26、ring use, check the temperature of the air in the centre part of the cabinet. The air temperature shall be between28 C and30 C, with the mixer mounted, for at least10min before the first test portion is placed into the mixer. During use, the air temperature shall be (30 0,2) C. 8.2.2 Adjust the arm

27、of the recorder pen so as to obtain zero deflection with the mixing blades rotating in the empty, clean bowl. Adjust the damper so that, with the motor running, the time required for the recorder pen to go from1000VU to100VU is (1,0 0,2)s. 8.2.3 Fill the burette with water. Fill the tip of the buret

28、te by letting about1ml of water flow into a vessel; fill the burette again. 8.3 Test portion Weigh, to the nearest0,1g, the equivalent of50g of flour having a moisture content of14% (m/m). Let this mass, in grams, be m; see Table 1 for m as a function of moisture content. Switch off the heating. Pla

29、ce the flour into the mixer. Cover the mixer, and keep it covered until the end of mixing(8.4.1), except for the shortest possible time, when water has to be added, and the dough scraped down (seeA.2.2). Switch on the thermostatically controlled heating. 8.4 Determination 8.4.1 Mix for1min or slight

30、ly longer. Start adding water from the burette into the mixer, when a whole-minute line on the recorder paper passes by the pen. NOTEIn order to reduce the waiting time, the recorder paper may be moved forward during the mixing of the flour. Do not move it backwards. Add a volume of water close to t

31、hat expected to produce a maximum consistency(9.1) of500VU. When the dough forms, scrape down the sides of the bowl with the spatula(6.3), adding any adhering particles to the dough, without stopping the mixer. If the consistency is too high, add a little more water to obtain a maximum consistency(9

32、.1) of approximately500VU. Stop mixing and clean the mixer. 8.4.2 After cleaning, place the parts of the mixer for at least2min in the water-bath(6.4) at a temperature of(31 1) C. Dry and mount them rapidly. Wait for at least5min, with the temperature control operating, before the next mixing. 8.4.3

33、 Make further mixings as necessary, until two mixings are available in which the water addition has been completed within25s; the maximum consistencies(9.1) of which are between480VU and520VU; and the recording of which has been continued for at least12min after the end of the development time(9.2),

34、 if the degree of softening is to be reported. Stop mixing and clean the mixer. Between successive mixings, repeat the operations specified in8.4.2. 9 Expression of results 9.1 Water absorption From each of the mixings with maximum consistencies between480VU and520VU, derive the corrected volume V c

35、 , in millilitres, of water corresponding to a maximum consistency of500VU, by means of the formula V c = V +0,016 (c 500) where where NOTEIn the relatively infrequent case where two maxima are observed, use the height of the higher maximum. Use for the calculation the mean value of duplicate determ

36、inations of V c , provided that the difference between them does not exceed0,5ml of water. The valorigraph water absorption, expressed in millilitres per100g of flour at14% (m/m) moisture content, is equal to (+m 50) 2 V is the volume, in millilitres, of water added; c is the maximum consistency, in

37、 valorigraph units, (see Figure 1) given by c 1 is the maximum height of the upper contour of the curve, in valorigraph units; c 2 is the maximum height of the lower contour of the curve, in valorigraph units. c c 1 c 2 + 2 - = V cBS4317-22:1989 BSI 08-1999 3 where Report the result to the nearest0,

38、1ml per100g. 9.2 Dough development time The dough development time is the time from the beginning of addition of water to the point on the curve immediately before the first signs of the decrease of consistency (see Figure 1). NOTEIn the relatively infrequent case where two maxima are observed, use

39、the second maximum to measure the development time. Take as the result the mean dough development time from the two curves to the nearest0,5min, provided that the difference between them does not exceed1min for development times of up to4min, or25% of their mean value for longer development times. 9

40、.3 Degree of softening The degree of softening is the difference in height between the centre of the curve at the end of the dough development time and the centre of the curve12min after this point (see Figure 1). Table 1 Mass of flour, in grams, equivalent to50g, at a moisture content of14% (m/m) i

41、s the numerical value of the mean value of the duplicate determinations of the corrected volume, in millilitres, of water corresponding to a maximum consistency of500VU; m is the numerical value of the mass, in grams, of the test portion derived from Table 1. V c Moisture content % (m/m) Mass m of f

42、lour Moisture content % (m/m) Mass m of flour Moisture content % (m/m) Mass m of flour 9,0 9,1 9,2 9,3 9,4 9,5 9,6 9,7 9,8 9,9 10,0 10,1 10,2 10,3 10,4 10,5 10,6 10,7 10,8 10,9 11,0 11,1 11,2 11,3 11,4 11,5 11,6 11,7 11,8 11,9 12,0 47,3 47,3 47,4 47,4 47,5 47,5 47,6 47,6 47,7 47,7 47,8 47,8 47,9 47,

43、9 48,0 48,0 48,1 48,2 48,2 48,3 48,3 48,4 48,4 48,5 48,5 48,6 48,6 48,7 48,8 48,8 48,9 12,1 12,2 12,3 12,4 12,5 12,6 12,7 12,8 12,9 13,0 13,1 13,2 13,3 13,4 13,5 13,6 13,7 13,8 13,9 14,0 14,1 14,2 14,3 14,4 14,5 14,6 14,7 14,8 14,9 15,0 48,9 49,0 49,0 49,1 49,1 49,2 49,3 49,3 49,4 49,4 49,5 49,5 49,

44、6 49,7 49,7 49,8 49,8 49,9 49,9 50,0 50,1 50,1 50,2 50,2 50,3 50,4 50,4 50,5 50,5 50,6 15,1 15,2 15,3 15,4 15,5 15,6 15,7 15,8 15,9 16,0 16,1 16,2 16,3 16,4 16,5 16,6 16,7 16,8 16,9 17,0 17,1 17,2 17,3 17,4 17,5 17,6 17,7 17,8 17,9 18,0 50,6 50,7 50,8 50,8 50,9 50,9 51,0 51,1 51,1 51,2 51,3 51,3 51,

45、4 51,4 51,5 51,6 51,6 51,7 51,7 51,8 51,9 51,9 52,0 52,1 52,1 52,2 52,2 52,3 52,4 52,4 NOTEThe values in this table were calculated using the formula where H is the moisture content of the sample, as a percentage by mass. m 4 300 100H - =BS4317-22:1989 4 BSI 08-1999 Take as the result the mean degre

46、e of softening from the two curves to the nearest5VU, provided that the difference between them does not exceed20VU for degrees of softening up to80VU, or25% of their mean value for larger values. 9.4 Repetition If one or more of the differences between measurements on the two curves exceed the valu

47、es specified in9.1 to9.3 inclusive, make another two mixings that meet the requirements of8.4.3. 9.5 Precision The precision data were determined from an experiment conducted in1985 involving11laboratories,4 levels, and determinations in duplicate as specified in the method (seeTable 2). 10 Test rep

48、ort The test report shall specify the method used and the results obtained. It shall also mention all operating details not specified in this part of ISO5530, or regarded as optional, together with details of any incidents which may have influenced the results. The test report shall include all info

49、rmation necessary for the complete identification of the sample. Table 2 Precision of valorigraph measurements Figure 1 Representative valorigram showing the commonly measured indices Repeatability Reproducibility Water absorption Dough development time Degree of softening 0,7ml per100g of flour 1,0min up to80VU: 20VU above80VU: 25% of mean value 5ml per100g of flour Results inconclusive 60% of mean valueBS4317-22:1989 BSI 08-1999 5 Annex A (informative) Description of the valori