इंटरनेट मानक Disclosure to Promote the Right To Information Whereas the Parliament of India has set out to provide a practical regime of right to information for citizens to secure access to information under the control of public authorities, in order to promote transparency and accountability in the working of every public authority, and whereas the attached publication of the Bureau of Indian Standards is of particular interest to the public, particularly disadvantaged communities and those engaged in the pursuit of education and knowledge, the attached public safety standard is made available to promote the timely dissemination of this information in an accurate manner to the public. “जान1 का अ+धकार, जी1 का अ+धकार” “प0रा1 को छोड न' 5 तरफ” “The Right to Information, The Right to Live” “Step Out From the Old to the New” Mazdoor Kisan Shakti Sangathan Jawaharlal Nehru IS 13852 (1994): Tea - Preparation of ground sample of known dry matter content [FAD 6: Stimulant Foods] “!ान $ एक न' भारत का +नम-ण” Satyanarayan Gangaram Pitroda “Invent a New India Using Knowledge” “!ान एक ऐसा खजाना > जो कभी च0राया नहB जा सकता ह” है” ह Bhartṛhari—Nītiśatakam “Knowledge is such a treasure which cannot be stolen” . IS 13852 : 1994 IS0 1572 : 1980 ( Reaffirmed 1999 ) Indian Standard TEA - PREPARATION OF GROUND SAMPLE OF KNOWN DRY MATTER CONTENT UDC 663’95 : 620’113 @I BIS 1994 BUREAU MANAK OF BHAVAN, INDIAN 9 BAHADUR NEW DELHI February 1994 STANDA-RDS SHAH ZAFAR MARG 110002 Price Group 1 Stimulant Foods NATIONAL Sectional Committee, FAD 23 FOREWORD This Indian Standard which is identical with IS0 1572 : 1980 ‘Tea - Preparation of ground sample of known dry matter content’ issued by the International Organization for Standardization ( IS0 ) was adopted by the Bureau of Indian Standards on the recommendation of the Stimulant Foods Sectional Committee ( FAD 23 ), and approval of the Fo3d and Agriculture Division Council. In the adopted standard certain terminology and in Indian Standards; attention is drawn specially a) Wherever the words ‘International should be read as ‘Indian Standard’; b) Comma practice conventions are not identical to the following : Standard’ and appear, ( , ) has been used as a decimal marker, while is to use point ( . ) as the decimal marker. referring in with those used to this standard, Indian Standard they the current CROSS REFERENCES In this adopted standard, reference appears to certain International Standards for which fndian Standards also exist. The corresponding Indian Standards which are to be substituted in their place are listed below along with their degree of equivalence for the editions indicated: International Standard Indian IS0 565 : 1990, Test sieves - Metal wire cloth, perforated metal plate and electro-formed sheet - Nominal sizes of openings IS 460 sieves Part 1 Part 2 IS0 IS 3611 : 1975 Method ing for tea ( first revision 1839 : 1980 : 1985 Standard Degree of Correspondence Specification for test Technically : Wire cloth test sieves Perforated plate test sieves of ) sampl- equivalent Technically equivalent In reporting the result of a test or analysis made in accordance with the standard, if the observed or calculated, is to be rounded off, it shall be done in accordance value, IS 2 : 1960 ‘Rules for rounding off numerical values ( revised )‘. finaT with IS 13852 : 1994 IS0 1572 : 1980 fndian Standard TEA - PREPARATION OF GROUND SAMPLE OFF KNOWN DRY MATTER CONTENT 1 Scope 5.3 Weighing lid. and field of application This International Standard specifies a method of preparing a ground sample of tea and of determining its dry matter content, for use in analytical determinations which require the results to be expressed on the dry basis. 2 References IS0 1839, Tea -- Woven metal Nominal wire cloth sizes of squat form, with airtight 5.4 Constant-temperature being controlled at 103 f 5.5 Desiccator, desiccant. 5.6 Analytica-I IS0 565, Test sieves and perforated plate apertures. bottle, oven, 2°C. containing an efficient balance 6 Sampling Sample the tea in accordance with IS0 1839. 7 Preparation Sampling. 3 Definition For the pupose of this International the following definition applies: Standard, dry matter : The matter remaining when a ground sample of the product is heated to constant mass under the conditions specified. 4 Principle Grinding of the sample, and determination of the dry matter content of the ground sample by heating a test portion in an oven at 103 rt 2°C to constant mass. 5 Apparatus of ground sarllple Using the grinding mill ‘( 5.1 ), grind a small quantity of the sample and reject it, then quickly grind an amount slightly greater than that required for the specified tests and for the determination of dry matter content. If the moisture content is too high for satisfactory grinding of the sample to the fineness specified in 5.1, it is necessary to pre-dry a portion of the sample to be ground, in an oven to a sufficient degree of dryness. Carry out the grinding after the pre-dried sample has been allowed to cool. Transfer the grindings to the previously dried sample container ( 5.2 ) and immediately close the latter. Usual laboratory apparatus not specified, and the following items: o~therwise 8 Determination of dry matter of ground sample 5.1 Grinding mill. characteristics: having followjng 8.1 Preparation - made of material moisture; which - easy to clean and space as possible; capable of the as little dead - adjusted so as to produce particles which will pass completely through a sieve of aperture size 500 pm ( see IS0 565 ). 5.2 Sample container, clean, dry, airtight, made of glass or other suitable material which has no action on the sample and of such a size that it will be nearly completely filled by the ground sampl_e. bottle Remove the lid from the weighing bottle ( 5.3 ) and heat both for 1 h in the oven ( 5.4 ) at Cool in the desiccator ( 5.5 ). 103 f 2°C. After cooling, fit the lid and weigh to the nearest 0.001 g. does not absorb having of weighing content 8.2 Test portion Weigh, to the nearest 0,001 g, about 5 g of the sample in the prepared weighing ground bottle ( 8.1 ). 8.3 Determination Heat the weighing bottle and contents, with the lid removed but alongside the bottle, in the 1 IS 13852 : 1994 IS0 1572 : 1980 oven ( 5.4 ) at 103 f 2°C for 6 h. Cool in the desiccator ( 5.5 1, fit the lid and weigh. Return the bottle and its lid to the oven and heat again for 1 h, cool in the desiccator, fit the lid, and weigh, repeating these operations if necessary, until the difference between two successive weighings does not exceed 0,005 g. 8.4 Number mlX 8.5 Note on drying on the procedure In general, a single 16 h period in the oven at 103 f 2°C gives equivalent results, but it is the responsibility of the analyst to confirm this in each particular case. 8.6 Expression Method The dry matter of results of calculation content and formula of the ground sample, by mass, is i!!Z!Y! m0 where m0 is the initial mass, in grams, of the test portion; ml is the mass, in grams, of the dried test portion. of determinations Carry out two separate determinations same ground sample ( clause 7 1. 8.6.1 RS, expressed as a percentage given by the formula Take as the result the arithmetic mean of the two determinations, provided that the requirement for repeatability ( see 8.6.2 ) is satisfied. 8.6.2 Repeatability The difference between the results of two determinations, carried out simultaneously or in rapid succession by the same analyst, shall not exceed 0,3 g of dry matter per 100 g of sample. 2 Bureau of Indian Standards BIS is a statutory institution established under the Bureau of Indian; Standards Act, promote harmonious development of the activities of stadardization, marking and certification of goods and attending to connected matters in the country. 1986 to quality Copyright BIS has the copyright of al~l its publications. No part of these publications may be reproduced in any form without the prior permission in writing of BIS. This does not preclude the free use, in the course of implementing the standard, of necessary details, such as symbols and sizes, type or grade designations. Enquiries relating to copyright be addressed to the Director ( Publications ), BIS. Revision of Indian Standards Amendments are issued to standards as the need arises on the basis of comments. Standards are also reviewed periodically; a standard along with amendments is reaffirmed when such review indicates that no changes are needed; if the review indicates that changes are needed, it is taken Users of Indian Standards should ascertain that they are in possession of the up for revision. latest amendments or edition by referring to the latest issue of ‘BIS Handbook’ and ‘Standards Monthly Additions’. This Indian Standard has been developed from Dot : No. FAD 23 ( 332 ). 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