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SIST ISO 937:1995
01-avgust-1995
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Meat and meat products -- Determination of nitrogen content (Reference method)
Viandes et produits à base de viande -- Détermination de la teneur en azote (Méthode
de référence)
Ta slovenski standard je istoveten z: ISO 937:1978
ICS:
67.120.10 Meso in mesni proizvodi Meat and meat products
SIST ISO 937:1995 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
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SIST ISO 937:1995
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SIST ISO 937:1995
INTERNATIONAL STANDARD 937
INTERNATIONAL ORGANIZATION FOR STANDARDIZATlON.ME~YHAPO~HAR OPl-AHbl3Ai.&lR I-IO CTAHAAPTM3AL(MMeORGANlSATlON INTERNATIONALE DE NORMALISATION
Meat and meat products - Determination of nitrogen
content (Reference method)
Viandes et produits ;i base de viande - D&termination de la teneur en azote (M&hode de re’fgrence)
First edition - 1978-12-15
Ref. No. IS0 937-1978 (E)
UDC 637.5 + 664.9 : 543.846
chemical analysis, determination of content, nitrogen.
Descriptors : meat, meat products,
Price based on 3 pages
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SIST ISO 937:1995
FOREWORD
IS0 (the International Organization for Standardization) is a worldwide federation
of national standards institutes (IS0 member bodies). The work of developing
International Standards is carried out through IS0 technical committees. Every
member body interested in a subject for which a technical committee has been set
up has the right to be represented on that committee. International organizations,
governmental and non-governmental, in liaison with ISO, also take part in the work.
Draft International Standards adopted by the technical committees are circulated
to the member bodies for approval before their acceptance as International
Standards by the IS0 Council.
IS0 937 was developed by Technical Committee
International Standard
ISO/TC 34, Agricultural food products.
It was submitted directly to the IS0 Council, in accordance with clause 6.13.1 of
the Directives for the technical work of ISO. It cancels and replaces IS0 Recommen-
dation R 937-1969, which had been approved by the member bodies of the
following countries :
Hungary Romania
Australia
Bulgaria India South Africa, Rep. of
Canada Iran Thailand
Ireland Turkey
Colombia
Israel United Kingdom
Czechoslovakia
Korea, Rep. of U.S.S. R.
Egypt, Arab Rep. of
Norway Yugoslavia
France
Poland
Germany, F. R.
Greece Portugal
The member bodies of the following countries had expressed disapproval of the
document on technical grounds :
Netherlands
New Zealand
0 International Organization for Standardization, 1978 l
Printed in Switzerland
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SIST ISO 937:1995
--~
_-.-
ISO937-1978 (E)
INTERNATIONAL STANDARD
Meat and meat products - Determination of nitrogen
content (Reference method)
5.5 Boric acid solution.
1 SCOPE AND FIELD OF APPLICATION
Dissolve 40 g of boric acid (H,BO,) in water and dilute to
This International Standard specifies a reference method
1 000 ml.
for the determination of the nitrogen content of meat and
meat products?
5.6 Hydrochloric acid, 0,l N standard volumetric solution,
the normality being known to four decimal places.
2 REFERENCE
IS0 3100, Meat and meat products - Smpling. 5.7 Indicator solution : mixed indicator (methyl red-
methylene blue)*), prepared by dissolving 2 g of methyl
red and 1 g of methylene blue in 1 000 ml of 95 % (V/V)
3 DEFINITION
ethanol.
nitrogen content of meat and meat products : The quantity
The colour change of this indicator solution occurs at a
of nitrogen corresponding to the ammonia produced and
pH of 5,4.
determined under the conditions specified below.
Store the indicator solution in a brown bottle in a dark and
cool place.
4 PRINCIPLE
5.8 Boiling regulators.
Digestion of a test portion with concentrated sulphuric
acid, using copper( II) sulphate as a catalyst, to convert
5.8.1 For the digestion
organic nitrogen to ammonium ions; alkalisation, distilla-
tion of the liberated ammonia into an excess of boric acid
Glass beads, silicon carbide or splinters of hard porcelain.
solution, titration with hydrochloric acid to determine the
ammonia bound by the boric acid, and calculation of the
5.8.2 For the distillation
nitrogen content of the sample from the amount of
ammonia produced.
Silicon carbide or freshly ignited pieces of pumice stone.
5 REAGENTS
6 APPARATUS
All reagents shall be of recognized analytical quality. The
water used shall be distilled water or water of at least
Usual laboratory apparatus not otherwise specified, and the
equivalent purity.
following items :
5.1 Copper(R) sulphate pentahydrate (CuS0,.5H,O).
6.1 Mechanical meat mincer, laboratory s
...