1、BRITISH STANDARD BS 4317-19: 1990 Methods of test for Cereals and pulses Part 19: Determination of protein quality of wheat by the sodium dodecyl sulphate (SDS) test UDC 633.11:664.38:006.83:546.33:547.268.15:546.226:543.05BS4317-19:1990 This British Standard, having been prepared under the directio
2、nof the Food and Agriculture Standards Policy Committee, was published underthe authority of the BoardofBSI and comes into effect on 28 February 1990 BSI 08-1999 The following BSI references relate to the work on this standard: Committee reference FAC/4 Draft for comment 88/54719 DC ISBN 0 580 17817
3、 X 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 Agricultura
4、l 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 Authority Instit
5、ute 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 Society
6、of Chemical Industry United Kingdom Agricultural Supply Trade Association Ltd. Amendments issued since publication Amd. No. Date CommentsBS4317-19:1990 BSI 08-1999 i Contents Page Committees responsible Inside front cover Foreword ii 1 Scope 1 2 Principle 1 3 Reagents 1 4 Apparatus 1 5 Sampling 1 6
7、Preparation of the test sample 1 7 Procedure 1 8 Expression of results 2 9 Test report 2 Table 1 Summary of procedure showing elapsed time 1 Publications referred to Inside back coverBS4317-19:1990 ii BSI 08-1999 Foreword This Part of BS 4317 has been prepared under the direction of the Food and Agr
8、iculture Standards Policy Committee. The sodium dodecyl sulphate (SDS) test is used as a measure of the protein quality of wheat for analytical, technical and contractual purposes. It is hoped that the publication of this Part of BS4317 will facilitate the use of the test for legal purposes in place
9、 of other methods. 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. Summary of pages This
10、document comprises a front cover, an inside front cover, pages i and ii, pages1 and 2, an inside back 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.BS4317-1
11、9:1990 BSI 08-1999 1 1 Scope This Part of BS4317 describes a method for carrying out the sodium dodecyl sulphate (SDS) test in the determination of the protein quality of wheat. NOTEThe titles of the publications referred to in this standard are listed on the inside back cover. 2 Principle A ground
12、sample of wheat is suspended in a solution of sodium dodecyl sulphate containing lactic acid, inverted several times, and allowed to settle. The volume of the sediment is measured. 3 Reagents 3.1 General. All reagents shall be of a recognized analytical grade. 3.2 Water, complying with grade3 of BS3
13、978. 3.3 SDS reagent. Dissolve20g of sodium dodecyl sulphate (formerly known as sodium lauryl sulphate), specially pure, in1 L of water, add20mL of diluted lactic acid solution (10mL of lactic acid solution88% m/m diluted further with80mL of water) and mix thoroughly. 4 Apparatus 4.1 Ordinary labora
14、tory apparatus and the apparatus described in4.2 to4.4. 4.2 Measuring cylinders, stoppered, of100mL capacity, with a distance of160 3mm between the0mL and100mL graduations. 4.3 Water bath, capable of being controlled at22 1 C. 4.4 Stop clock 5 Sampling The laboratory sample shall have been taken in
15、accordance with BS4510. 6 Preparation of the test sample Grind a representative portion of the laboratory sample (see clause5) so that it passes through a sieve with0.8mm apertures. NOTEA KT mill is suitable. 7 Procedure NOTE 1The procedure is written so that four tests may be carried out at the sam
16、e time in the measuring cylinders (4.2), numbered1 to4, but the number of tests may be varied according to circumstances. NOTE 2All the test portions should be prepared in advance. NOTE 3The procedure is summarized inTable 1. 7.1 Pour 50 mL of water (3.2), into each of the numbered measuring cylinde
17、rs (4.2) and50mL of the SDS reagent (3.2) into the same number of unstoppered50mL measuring cylinders. Stand all the cylinders in the water bath (4.3), controlled at22 1 C, until the temperature of the contents reaches22 1 C. NOTEThe water and the SDS reagent may be preheated to22 C by being kept in
18、 the water bath. 7.2 Remove cylinder1 from the water bath. Add a test portion of6.0 0.05g of the test sample (clause6) calculated at15.0% m/m moisture content to the cylinder and start the stop clock (4.4). Keep the clock running until the procedure is completed. Stopper the cylinder and shake it vi
19、gorously in a horizontal plane for15s using approximately36 movements of approximately18cm. Return the cylinder to the water bath. NOTEThe moisture content of the test sample is determined after milling using a rapid instrumental method. 7.3 Repeat the procedure in7.2 with each test portion at30s in
20、tervals in the cylinders numbered2,3 and4. 7.4 After 2 min repeat the shaking of each cylinder. 7.5 After 2 min repeat the shaking of each cylinder. Immediately after each shaking, add50mL of SDS reagent and invert each cylinder4times. 7.6 After 2 min, invert each cylinder4times. Table 1 Summary of
21、procedure showing elapsed time Cylinder number Operation Shake in water for 15 s (7.2) Shake in water for 15 s (7.4) Shake in water for 15 s, add SDS reagent, invert 4times (7.5) Invert 4 times (7.6) Invert 4 times (7.7) Invert 4 times (7.8) Read sedimentation volume (7.9) min min min min min min mi
22、n 1 0.0 2.0 4.0 6.0 8.0 10.0 30.0 2 0.5 2.5 4.5 6.5 8.5 10.5 30.5 3 1.0 3.0 5.0 7.0 9.0 11.0 31.0 4 1.5 3.5 5.5 7.5 9.5 11.5 31.5BS4317-19:1990 2 BSI 08-1999 7.7 After 2 min, invert each cylinder4times. 7.8 After 2 min, invert each cylinder4times. 7.9 After 20 min, read the volume of sediment in eac
23、h cylinder to the nearest mL. 8 Expression of results Express the SDS value as the volume of the sediment in mL. 9 Test report The test report shall show the method used, i.e.BS4317-19:1990, and the results obtained. It shall also mention all operating details not specified or regarded as optional,
24、together with details of any incidents likely to have influenced the results. The test report shall include all the information necessary for the complete identification of the sample.BS4317-19:1990 BSI 08-1999 Publications referred to BS 3978, Specification for water for laboratory use. BS 4510, Me
25、thods for sampling cereals (as grain). BS 4317-19: 1990 BSI 389 Chiswick High Road London W4 4AL BSIBritishStandardsInstitution BSI is the independent national body responsible for preparing BritishStandards. It presents the UK view on standards in Europe and at the international level. It is incorp
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