BS 5752-14-1995 Methods of test for coffee and coffee products - Roasted ground coffee - Determination of moisture content (loss in mass at 103 C (routine method)《咖啡和咖啡制品试验方法 烤粗咖啡 .pdf

1、BRITISH STANDARD BS5752-14: 1995 ISO11294: 1994 Methods of test for Coffee and coffee products Part 14: Roasted ground coffee: Determination of moisture content loss in mass at103 C (routine method)BS5752-14:1995 This British Standard, having been prepared under the directionof the Consumer Products

2、 and Services SectorBoard, was published undertheauthority of the StandardsBoard and comes into effect on 15 February1995 BSI10-1999 The following BSI references relate to the work on this standard: Committee referenceAW/15 Draft for comment92/57072DC ISBN 0 580 23813 X Committees responsible for th

3、is British Standard The preparation of this British Standard was entrusted to Technical CommitteeAW/15, Coffee, upon which the following bodies were represented: Association of Public Analysts British Soluble Coffee Manufacturers Association Coffee Trade Federation Ltd. Food and Drink Federation Ins

4、titute of Trading Standards Administration Ministry of Agriculture, Fisheries and Food Natural Resources Institute Amendments issued since publication Amd. No. Date CommentsBS5752-14:1995 BSI 10-1999 i Contents Page Committees responsible Inside front cover National foreword ii 1 Scope 1 2 Definitio

5、n 1 3 Principle 1 4 Apparatus 1 5 Sampling 1 6 Preparation of test sample 1 7 Procedure 1 8 Expression of test results 1 9 Precision 1 10 Test report 2 Annex A (informative) Results of interlaboratory test 3 Table A.1 Determination of loss in mass for roasted ground coffee 3 Table A.2 Comparison of

6、loss in mass values with moisture content values determined by Karl Fischer method 3 List of references Inside back coverBS5752-14:1995 ii BSI 10-1999 National foreword This Part of BS5752 has been prepared under the direction of the Consumer Products and Services Sector Board. It is identical with

7、ISO11294:1994 Roasted ground coffee Determination of moisture content Method by determination of loss in mass at103 C (Routine method), published by the International Organization for Standardization (ISO) and in the preparation of which the UnitedKingdom played a full part. This standard embodies a

8、n agreement, to which the UK was a party, reached in Subcommittee15, Coffee, of Technical Committee34, Agricultural food products, of ISO. A British Standard does not purport to include all the necessary provisions of a contract. Users of British Standards are responsible for their correct applicati

9、on. Compliance with a British Standard does not of itself confer immunity from legal obligations. Cross-reference International Standard Corresponding British Standard ISO5725:1986 BS5497 Precision of test methods Part 1:1987 Guide for the determination of repeatability and reproducibility for a sta

10、ndard test method by inter-laboratory tests (Identical) Summary of pages This document comprises a front cover, an inside front cover, pagesi andii, pages1 to4, an inside back cover and a back cover. This standard has been updated (see copyright date) and may have had amendments incorporated. This w

11、ill be indicated in the amendment table on the inside front cover.BS5752-14:1995 BSI 10-1999 1 1 Scope This International Standard specifies a routine method for the determination of loss in mass at103 C of roasted ground coffee. NOTE 1This method has been shown to give very similar results on avera

12、ge to those obtained by the method given in ISO11817:, Roasted ground coffee Determination of moisture content Karl Fischer method (Reference method). This method is most suited to degassed roasted ground coffee, because of the presence of volatile matter, especially carbon dioxide, in variable quan

13、tities in roasted coffee. 2 Definition For the purposes of this International Standard, the following definition applies. 2.1 loss in mass at103 C loss in mass caused principally by water and volatile matter (carbon dioxide, volatile acids, etc.) which are vaporized under the conditions specified in

14、 this International Standard loss in mass is expressed as a percentage by mass 3 Principle Heating a test portion at103 C 1 C for2h at atmospheric pressure. 4 Apparatus Usual laboratory apparatus and, in particular, the following. 4.1 Oven, electrically heated, capable of being operated at103 C 1 C.

15、 4.2 Dish, made of corrosion-resistant metal or of glass, with lid and an effective surface area of at least18cm 2(for example,50mm minimum diameter and25mm to30mm deep). 4.3 Desiccator, containing an effective desiccant. 4.4 Analytical balance, capable of weighing to0,1mg. 5 Sampling It is importan

16、t that the laboratory receive a sample which is truly representative and has not been damaged or changed during transport or storage. 6 Preparation of test sample Mix thoroughly the laboratory sample. 7 Procedure 7.1 Preparation of the dish Dry the dish(4.2) and its lid for1h in the oven(4.1) set at

17、103 C. Remove the dish and its lid from the oven and allow them to cool to room temperature in the desiccator(4.3). Weigh the dish and its lid to the nearest0,1mg. 7.2 Test portion Place approximately5g of the test sample (clause6) in the prepared dish(7.1). Cover the dish with its lid and weigh the

18、 dish, lid and contents to the nearest0,1mg. 7.3 Determination Place the dish containing the test portion, with the lid removed but alongside or beneath the dish, in the oven(4.1) set at103 C, and dry for2h 0,1h. Remove the dish, fit the lid and place them in the desiccator(4.3). Allow the dish, lid

19、 and contents to cool to room temperature and then weigh them to the nearest0,1mg. 8 Expression of test results The loss in mass at103 C, expressed as percentage by mass of the sample, is calculated according to the following formula: 9 Precision Results of an interlaboratory test are given in Annex

20、 A. 9.1 Repeatability The absolute difference between two independent test results, obtained using the same method on identical test material in the same laboratory by the same operator using the same equipment within a short interval of time, should not be greater than0,1%. where m 0 is the mass, i

21、n grams, of the dish and lid (see7.1); m 1 is the mass, in grams, of the dish, test portion and lid before drying (see7.2); m 2 is the mass, in grams, of the dish, test portion and lid after drying (see7.3). m 1 m 2 ()100 m 1 m 0 -BS5752-14:1995 2 BSI 10-1999 9.2 Reproducibility The absolute differe

22、nce between two single test results, obtained using the same method on identical test material in different laboratories with different operators using different equipment, should not be greater than0,5%. NOTE 2The reproducibility of the test method is such that the method is less suitable for roast

23、ed ground coffees with low moisture contents (below approx.2% moisture). 10 Test report The test report shall specify the method used, the test result obtained, and if the repeatability has been checked, the final quoted result obtained. It shall also mention any operating details not specified in t

24、his International Standard, or regarded as optional, as well as any circumstances that may have influenced the result. The test report shall include all information required for the complete identification of the sample.BS5752-14:1995 BSI 10-1999 3 Annex A (informative) Results of interlaboratory te

25、st An interlaboratory test carried out in1989, in which15 laboratories participated, each of which carried out three determinations on each sample, gave the statistical results (evaluated in accordance with ISO5725 1) ) shown in Table A.1. In the same interlaboratory test, the same laboratories dete

26、rmined the true moisture content by the Karl Fischer method of ISO11817. Table A.2 shows the comparison of mean values obtained for each sample by the two methods. Table A.1 Determination of loss in mass for roasted ground coffee Table A.2 Comparison of loss in mass values with moisture content valu

27、es determined by the Karl Fischer method 1) ISO5725:1986, Precision of test methods Determination of repeatability and reproducibility for a standard test method by inter-laboratory tests. Sample A B C D E Number of laboratories retained after eliminating outliers 15 15 14 15 15 Mean loss in mass,%

28、(m/m) 4,98 4,54 3,20 1,56 1,50 Standard deviation of repeatability, s rCoefficient of variation of repeatability,% Repeatability2,83s r 0,031 0,6 0,09 0,011 0,9 0,12 0,027 0,8 0,08 0,027 1,7 0,08 0,021 1,4 0,06 Standard deviation of reproducibility, s RCoefficient of variation of reproducibility,% R

29、eproducibility2,83s R 0,187 3,7 0,5 0,168 3,7 0,5 0,281 8,8 0,8 0,187 12,0 0,5 0,154 10,3 0,4 Sample A B C D E Mean loss in mass,% (m/m) 4,98 4,54 3,20 1,56 1,50 Mean moisture content,% (m/m) 5,07 4,64 3,32 1,51 1,444 blankBS5752-14:1995 BSI 10-1999 List of references See national foreword.BS5752-14

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