BS 5086-3-1984 Analysis of butter - Method for determination of water content (routine method)《黄油分析 第3部分 含水量测定方法(常规法)》.pdf

1、BRITISH STANDARD BS 5086-3: 1984 Analysis of butter Part 3: Method for determination of water content (routine method) NOTE This Part should be read in conjunction with Part 1 “General introduction, including preparation of samples” published separately. UDC 637.2.074BS5086-3:1984 This British Stand

2、ard, having been prepared under the directionof the Dairying Standards Committee, was published under the authority ofthe Board of BSI and comes intoeffect on 30 April 1984 BSI 07-1999 The committees responsible for this British Standard are shown inPart 1 The following BSI references relate to the

3、work on this standard: Committee reference DAC/3 Draft for comment 83/54117 DC ISBN 0 580 13809 7 Amendments issued since publication Amd. No. Date of issue CommentsBS5086-3:1984 BSI 07-1999 i Contents Page Foreword ii 1 Scope 1 2 Principle 1 3 Sampling 1 4 Apparatus 1 5 Procedure 1 6 Expression of

4、the result 1 7 Repeatability 1 8 Test report 1 Publications referred to Inside back coverBS5086-3:1984 ii BSI 07-1999 Foreword This Part of this British Standard has been prepared under the direction of the Dairying Standards Committee. It describes a method of determination given in clause 2 of BS

5、5086:1974. A new Part 5 describes the remaining method given in BS 5086:1974 (determination of salt content) and that standard is therefore superseded and withdrawn. The maximum permissible amount of water in butter is governed by legislation 1)and consequently there is a need during manufacture and

6、 blending for a method for determination of the water content in the shortest possible time consistent with accuracy. This standard, which allows for the use of special-purpose balances designed for the determination of water in butter, describes a method based on one which has been developed and us

7、ed for a number of years in butter factories. The method is described in basic outline in the knowledge that adjustment of time schedules may be necessary to conform to the overall time limitation imposed by the requirements of any particular factory, and with the object of providing a method which

8、can be more rapidly carried out by the analyst than can the corresponding method described in Part 2 of this standard. 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

9、a British Standard does not of itself confer immunity from legal obligations. Summary of pages This 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 amend

10、ments incorporated. This will be indicated in the amendment table on the inside front cover. 1) For England and Wales: Statutory Instrument 1966, No. 1074, Food and Drugs; Composition and Labelling, “The Butter Regulations 1966”. For Scotland: Statutory Instrument 1966, No. 1252 (S95), “The Butter (

11、Scotland) Regulations1966”. For Northern Ireland: Statutory Rules and Orders of Northern Ireland 1966, No. 205, Food and Drugs, Composition and Labelling Butter.BS5086-3:1984 BSI 07-1999 1 1 Scope This Part of BS 5086 describes a method for the rapid determination of the water content of butter. The

12、 method is applicable to all types of butter. NOTEThe titles of the publications referred to in this standard are listed on the inside back cover. 2 Principle A known mass of butter is heated under controlled conditions in an open vessel to evaporate the volatile constituents and the loss in mass is

13、 determined. 3 Sampling Take a representative sample of the butter to be tested using, where appropriate, the procedures described in Part 1 of this standard. NOTEIn the routine rapid examination of butter the sample is not normally “creamed”. If “creaming” is necessary for a particular application,

14、 the procedure descrived in 5.2 of Part1:1984 for the preparation of the sample should be used. 4 Apparatus 4.1 Balance, capable of weighing to an accuracy of 5 mg. This may be a balance specially designed for determination of the water content of butter. 4.2 Beaker, metal, of such dimensions that l

15、osses through spurting or frothing are avoided. It is recommended that the minimum diameter should be 60 mm and the minimum height should be60mm. 4.3 Heating apparatus. A spirit burner, bunsen burner, or electric hot-plate, is suitable. 4.4 Beaker tongs, to hold the beaker by its outer surface only.

16、 4.5 Glass stirring rod, of suitable dimensions, for use if a hot-plate or a bunsen flame with a gauze is used to heat the beaker. 5 Procedure 5.1 Dry and weigh the metal beaker (together with the stirring rod, if used). Weigh into the beaker 9 g to 11 g of butter (see note 1) with an accuracy of 10

17、mg. 5.2 Heat the beaker and contents, agitating continuously and taking care to control the heating and agitation so that losses through spurting are avoided. This operation may be carried out, for example: a) by swirling the beaker, using the tongs, in a bunsen flame; b) by heating on wire gauze wi

18、th a ceramic centre, over a low bunsen flame, stirring with the glass rod; c) by heating on a hot-plate, stirring with the glass rod. 5.3 When the stage is reached at which there is a tendency for the heated butter to froth, slow down the rate of heating. Stop the heating when the colour of the non-

19、fatty solids changes from creamy-white to yellow-brown (see note 2). 5.4 Cool the beaker to the desired temperature (seenotes 3 and 4). Weigh the beaker and contents (including the stirring rod, if used) and record the loss in mass. NOTES to clause 5. NOTE 1The range permitted for the mass of the te

20、st portion accommodates the use of special-purpose butter balances. When using these the mass of butter should be that which gives the result either by direct reading of the balance scale or by the use of the appropriate nomogram. NOTE 2The correct end-point should be established on a range of butte

21、r samples by preliminary tests comparing the results with those obtained by the use of the reference method for determination of moisture content described in Part 2 of this standard. NOTE 3Cooling of the beaker and its contents may be accelerated by partial immersion in cold water followed by dryin

22、g the exterior of the beaker with a clean dry cloth. To prevent condensation of atmospheric moisture on the beaker do not cool below the ambient .air temperature. NOTE 4Where certain special-purpose balances are used and a correction has been previously determined, the beaker may be weighed without

23、cooling. 6 Expression of the result Calculate the result as follows. Percentage (m/m) water content where Express the result correct to one decimal place. 7 Repeatability The difference between the results (expressed in accordance with clause 6) of two determinations carried out in rapid succession

24、by the same analyst should not exceed 0.2 % absolute. 8 Test report The following information shall be included in the test report: a) the result, expressed in accordance with clause5; b) the number of this British Standard, i.e.BS5086-3; c) details of the sample identity. m 1 is the mass of butter

25、taken, and m 2 is the loss in mass recorded. 100 m 2 m 1 - =2 blankBS5086-3:1984 BSI 07-1999 Publications referred to BS 5086, Analysis of butter. BS 5086-1, General introduction including preparation of samples. BS 5086-2, Method for determination of water, solids-not-fat and fat contents (referenc

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