SIST EN ISO 1211:1998

Milk - Determination of fat content - Gravimetric method (Reference method) (ISO 1211:1984)

Describes several methods of measuring the figure-of-merit (G/T) of the receiving systems of earth stations.

Milch - Bestimmung des Fettgehaltes - Gravimetrisches Verfahren (Referenzverfahren) (ISO 1211:1984)

Diese Internationale Norm legt ein Referenzverfahren für die Bestimmung des Fettgehaltes von Rohmilch und bearbeiteter flüssiger Milch, teilentrahmter und entrahmter Milch fest, in der keine merkliche Trennung oder Fettspaltung eingetreten ist (siehe Anmerkung zu Abschnitt 8.1).

Lait - Détermination de la teneur en matiere grasse - Méthode gravimétrique (Méthode de référence) (ISO 1211:1984)

Décrit plusieurs méthodes de mesure du facteur de qualité (G/T) des systèmes de réception des stations terriennes.

Mleko - Določevanje maščobe - Gravimetrijska metoda (Referenčna metoda) (ISO 1211:1984)

General Information

• Status: Withdrawn
• Publication Date: 31-Jul-1998
• Withdrawal Date: 30-Nov-2001
• ICS: 67.100.10 - Milk and processed milk products
• Technical Committee: KŽP - Agricultural food products
• Current Stage: 9900 - Withdrawal (Adopted Project)
• Start Date: 01-Dec-2001
• Due Date: 01-Dec-2001
• Completion Date: 01-Dec-2001
• Ref Project: EN ISO 1211:1995 - Milk - Determination of fat content - Gravimetric method (Reference method) (ISO 1211:1984)

Relations

• Replaced By: SIST EN ISO 1211:2001 - Milk - Determination of fat content - Gravimetric method (Reference method) (ISO 1211:1999)
• Effective Date: 01-Dec-2001

Standards Content (Sample)

SLOVENSKI STANDARD
SIST EN ISO 1211:1998
01-avgust-1998
0OHNR'RORþHYDQMHPDãþREH*UDYLPHWULMVNDPHWRGD5HIHUHQþQDPHWRGD,62

Milk - Determination of fat content - Gravimetric method (Reference method) (ISO
1211:1984)
Milch - Bestimmung des Fettgehaltes - Gravimetrisches Verfahren (Referenzverfahren)
(ISO 1211:1984)
Lait - Détermination de la teneur en matiere grasse - Méthode gravimétrique (Méthode
de référence) (ISO 1211:1984)
Ta slovenski standard je istoveten z: EN ISO 1211:1995
ICS:
67.100.10 0OHNRLQSUHGHODQLPOHþQL Milk and processed milk
SURL]YRGL products
SIST EN ISO 1211:1998 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST EN ISO 1211:1998

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SIST EN ISO 1211:1998

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SIST EN ISO 1211:1998

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SIST EN ISO 1211:1998
International Standard
INTERNATIONAL ORGANIZATION FOR STANDARDlZATIONWvlEMJYHAPO~HAR OPrAHM3A~MR fl0 CTAHAAPTM3A~l4M~RGANlSATlON INTERNATIONALE DE NORMALISATION
Milk - Determination of fat content - Gravimetric
method (Reference method)
Dhtermination de la teneur en matike grasse - M&bode gravimktrique fM&hode de rkfkencel
Lait -
First edition - 1984-11-15
-~
UDC 637.12.043 : 543.85 Ref. No. IS0 1211-1984 (E)
Descriptors : agricultural products, dairy products, milk, chemical analysis, determination of content, fats, gravimetric analysis.
Price based on 8 pages

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SIST EN ISO 1211:1998
Foreword
IS0 (the international Organization for Standardization) is a worldwide federation of
national standards bodies (IS0 member bodies). The work of preparing International
Standards is normally carried out through IS0 technical committees. Each member
body interested in a subject for which a technical committee has been established has
the right to be represented on that committee. International organizations, govern-
mental 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. They are approved in accordance with IS0 procedures requiring at
least 75 % approval by the member bodies voting.
International Standard IS0 1211 was prepared by Technical Committee ISO/TC 34,
Agricultural food products.
It cancels and replaces IS0 Recommendation R 1211-1970, of which it constitutes a
technical revision.
NOTE - The method specified in this International Standard has been developed jointly with the
IDF (International Dairy Federation) and the AOAC (Association of Official Analytical Chemists,
USA). The text as approved by the above organizations will also be published by FAO/WHO
(Code of principles concerning milk and milk products and associated standards), by the IDF and
by the AOAC (Official Methods of Analysis).
0 International Organization for Standardization, 1984
Printed in Switzerland

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SIST EN ISO 1211:1998
INTERNATIONAL STANDARD IS0 1211-1984 (E)
rmination of fat content - Gravimetric
Milk -
method (Reference method)
1 Scope and field of application
0 Introduction
This International Standard specifies the reference method for
This International Standard constitutes a revision of
the determination of the fat content of raw and processed
ISO/R 1211. Attempts to produce a single International Stan-
dard specifying the use of the Rose-Gottlieb method applicable liquid milk, partly skimmed milk and skimmed milk in which
no appreciable separation or splitting of fat has occurred (see
to all milk products have been found impracticable for the time
the note to 8.1).
being. Therefore, it has been decided to revise and harmonize
the existing standardized methods for individual products or
NOTE - When greater accuracy is required for skimmed milk, for in-
groups of products and to standardize similar methods for
stance to establish the operating efficiency of cream separators, the
those products for which methods had not been prepared
special method for skimmed products, specified in IS0 7208, Sklinmed
previously.
milk, whey and buttermilk - Determination of fat content -
Gravimetric method (Reference method), should be used.
The main modifications as compared to ISO/R 1211 are :
a) preference is given to the use of Mojonnier-type fat-
2 References
extraction flasks and the use of a centrifuge to separate the
solvent layers;
IS0 707, Milk and milk products - Methods of sampling.
b) addition of ethanol before the second extraction;
IS0 3889, Milk and rndk products - Determination of fat con-
tent - Mojonnier- type fat extraction flasks.
c) emphasis is placed on the necessity of cooling the fat-
collecting vessels to ambient temperature before performing
weighings.
3 Definition
The use of a centrifuge enables rapid and complete separation
fat content of milk : All the substances determined by the
of the solvent layers and minimizes the need for redissolution of
method specified in this International Standard.
the extracted fat or a repetition of the determination.
It is expressed as a percentage by mass.
The addition of ethanol before the second extraction has been
specified to reduce the risk of formation of a viscous or gelified
aqueous layer, especially in the case of products containing
4 Principle
sucrose (for example sweetened condensed milk, edible ices
and, to a lesser extent, milk powder). It has been found that
Extraction of an ammoniacal ethanolic solution of a test portion
this addition distinctly improves the precision of the method,
also for milk. with diethyl ether and light petroleum, removal of the solvents
by distillation or evaporation, and determination of the mass of
the substances extracted which are soluble in light petroleum.
Emphasis has been placed on the necessity of cooling fat-
(This is usually known as the Rose-Gottlieb principle.)
collecting vessels to ambient temperature before weighing, as
errors from this source of the order of 0,Ol % fat per degree
Celsius have been reported for liquid milk. The use of a desic-
cator is therefore not recommended. The use of an empty con- 5 Reagents
trol vessel will compensate for these errors to some extent. It
has been found, however, that the use of such a vessel All reagents shall be of recognized analytical grade and shall
together with a blank test on 10 ml of water carried out with the leave no appreciable residue when the determination is carried
out by the method specified. The water used shall be distilled
determination is complicated and produces no improvement in
precision. water or water of at least equivalent purity.
An empty control vessel is, however, necessary, and is To test the quality of the reagents, carry out a blank test as
therefore specified when performing the blank test to check the specified in 8.3. Use an empty fat-collecting vessel, prepared as
reagents in order to avoid a false impression of the presence or specified in 8.4, for mass control purposes. The reagents shall
absence of non-volatile matter. leave no residue greater than 0,5 mg (see 10.1).

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SIST EN ISO 1211:1998
IS0 1211-1984 (E)
If the residue of the complete reagent blank test is greater than 6.3 Distillation or evaporation apparatus, to enable the
0,5 mg, determine the residue of the solvents separately by solvents and ethanol to be distilled from the flasks or to be
evaporated from beakers and dishes (see 8.5.12) at a
distilling 100 ml of the diethyl ether and light petroleum respec-
tively. Use an empty control vessel to obtain the real mass of temperature not exceeding 100 OC.
residue which shall not exceed 0,5 mg.
6.4 Drying oven, electrically heated, with ventilation port(s)
redistil
Replace unsatisfactory reagents or solvents, or
fully open, capable of being maintained at a temperature of
solvents.
102 + 2 OC throughout the working space. The oven shall be
fitted with a suitable thermometer.
5.1 Ammonia solution, containing approximately 25 %
.
b-n/m) of NH,, ezo = 910 g/l
6.5 Water-bath, capable of being maintained at 35 to 40 OC.
NOTE - If ammonia solution of this concentration is not available, a
more concentrated solution of known concentration may be used (see
6.6 Mojonnier-type fat-extraction flasks, as specified in
8.5.1).
IS0 3889.
5.2 Ethanol, or ethanol denatured by methanol, at least
NOTE - It is also possible to use fat-extraction tubes, with siphon
94 % (VW).
or wash-bottle fittings, but the procedure is then different and is
specified in the annex.
(See 10.5.)
The flasks (or tubes, see the note) shall be provided with good
quality bark corks or stoppers of other material (for example
Congo-red solution.
5.3
silicone rubber) unaffected by the reagents used. Bark corks
shall be extracted with the diethyl ether (5.4), kept in water at
Dissolve 1 g of Congo-red in water and dilute to 100 ml.
60 OC or more for at least 15 min, and shall then be allowed to
cool in the water so that they are saturated when used.
NOTE - The use of this solution, which allows the interface between
the solvent and aqueous layers to be seen more clearly, is optional (see
8.5.2). Other aqueous colour solutions may be used provided that they
6.7 Rack, to hold the fat-extraction flasks (or tubes) (see
do not affect the result of the determination.
6.6).
Diethyl ether, free from peroxides (see 10.3) and con-
5.4
Wash bottle, suitable for
68 use with the mixed solvent
taining no or not more than 2 mg/kg of antioxidants and com-
(5.6). A plastic wash bottle shall not be used.
plying with the requirements for the blank test (see clause 5,
and also 10.1 and 10.4).
6.9 Fat-collecting vessels, for example boiling flasks (flat-
bottomed), of capacity 125 to 250 ml, conical flasks, of ca-
5.5 Light petroleum, having any boiling range between 30
pacity 250 ml, or metal dishes. If metal dishes are used, they
and 60 OC.
shall preferably be of stainless steel, shall be flat-bottomed,
preferably with a spout, and shall have a diameter of 80 to
use by mixing 100 mm and a height of approximately 50 mm.
5.6 Mixed solvent, prepared shortly before
equal volumes of the diethyl ether (5.4) and the light pet roleum
(5.5).
6.10 Boiling aids, fat-free, of non-porous porcelain or
silicon carbide (optional in the case of metal dishes),
6 Apparatus
6.11 Measuring cylinders, of capacities 5 and 25 ml.
- Since the determination involves the use of
WARNING
volatile flammable solvents, electrical apparatus
employed shall be required to comply with legislation
6.12 Pipettes, graduated, of capacity 10 ml.
relating to the hazards in using such solvents.
Usual laboratory equipment, and in particular
6.13 Tongs, made of metal, suitable for holding flasks,
beakers or dishes.
.
61 Analytical balance.
6.2 Centrifuge, in which the fat-extraction flasks or tubes 7 Sampling
(6.6) can be spun at a rotational frequency of 500 to 600 min - 1
to produce a gravitational field of 80 g to 90 g at the outer end See IS0 707.
of the flasks or tubes.
All laboratory samples shall be kept at a temperature of 3 to
6 OC from the time of sampling to the time of commencing the
NOTE - The use of the centrifuge is optional but recommended (see
8.5.5).
procedure.
2

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SIST EN ISO 1211:1998
IS0 1211-1984 (E)
8 Procedure 8.5 Determination
8.5.1 Add 2 ml of the ammonia solution (W), or an
NOTE - The alternative procedure using fat-extraction tubes with
siphon or wash-bottle fittings (see the note to 6.6) is described in the equivalent volume of a more concentrated ammonia solution
annex.
(see the note to 5.11, and mix thoroughly with the test portion
in the small bulb of the flask. After the addition of the am-
monia, carry out the determination without delay.
81 . Preparation of the test sample
8.5.2 Add 10 ml of the ethanol (5.2) and mix gently but
Adjust the temperature of the laboratory sample (clause 7) to
thoroughly by allowing the contents of the flask to flow
35 to 40 OC, by means of the water-bath (6.5) if necessary. Mix
backward and forward between the two bulbs; avoid bringing
the sample thoroughly, but gently, by repeatedly inverting the
the liquid too near to the neck of the flask. If desired, add
sample bottle without causing frothing or churning, and cool
2 drops of the Congo-red solution (5.3).
quickly to approximately 20 OC.
Churned milk should not be cooled as it has to be weighed at 30
8.5.3 Add 25 ml of the diethyl ether (5.41, close the flask with
to 40 OC in 8.2.
a cork (see 6.6) saturated with water or with a stopper of other
material (see 6.6) wetted with water, and shake the flask
content cannot be expected :
NOTE - A reliable value for the fat
vigorously, but not excessively (in order to avoid the formation
if the milk is churned;
a)
of persistent emulsions), for 1 min with the flask in a horizontal
position and the small bulb extending upwards, periodically
when a distinct smell of free fatty acids is perceptible;
b)
allowing the liquid in the large bulb to run into the small bulb. If
c) if during, or after, preparation of the sample, white particles
necessary, cool the flask in running water, then carefully
are visible on the walls of the sample bottle or fat droplets float on
remove the cork or stopper and rinse it and the neck of the flask
the surface of the sample.
with a little of the mixed solvent (5.6) using the wash bottle
(6.8) so that the rinsings run into the flask.
8.2 Test portion
8.5.4 Add 25 ml of the light petroleum (5.51, close the flask
Mix the test sample (8.1) by gently inverting the bottle three or
with the rewetted cork or rewetted stopper (by dipping in
four times and immediately weigh, to the nearest 1 mg, 10 to
water), and shake the flask gently for 30 s as described in 8.5.3.
11 g of the test sample, directly or by difference, into one of the
extraction flasks (6.6).
8.5.5 Centrifuge the closed flask for 1 to 5 min at a rotational
frequency of 500 to 600 min- 1. If a centrifuge is not available,
be delivered as completely
The test portion shal as possible
allow the closed flask to stand in the rack (6.7) for at least
into the I ower (small) bulb of the extraction flask.
30 min until the supernatant layer is clear and distinctly
separated from the aqueous layer. If necessary, cool the flask in
running water.
8.3 Blank test
Carry out a blank test simultaneously with the determination,
8.5.6 Carefully remove the cork or stopper and rinse it and the
using the same procedure and same reagents, but replacing the
inside of the neck of the flask with a little of the mixed solvent
test portion by 10 ml of water (see 10.2).
so that the rinsings run into the flask.
If the interface is below the bottom of the stem of the flask,
8.4 Preparation of fat-collecting vessel
raise it slightly above this level by gently adding water down the
side of the flask (see figure 1) to facilitate the decantation of
Dry a vessel (6.9) with a few boiling aids (6.10) in the oven (6.4)
solvent.
for 1 h. (See note 1.1
NOTE - In figures 1 and 2, one of the three types of flasks as specified
Allow the vessel to cool (protected from dust) to the
in IS0 3889 has been chosen, but this does not imply any preference
temperature of the weighing room (glass vessel for at least 1 h, over the other types.
metal dish for at least 0,5 h). (See note 2.)
8.5.7 Holding the extraction flask by the small bulb, carefully
Using tongs (to avoid, in particular, temperature variations),
decant as much as possible of the supernatant layer into the
place the vessel on the balance and weigh to the nearest
prepared fat-collecting vessel (see 8.4) containing a few boiling
0,l mg.
aids (6.10) in the case of flasks (optional with metal dishes),
avoiding decantation of any of the aqueous layer (see figure 2).
NOTES
1 Boiling aids are desirable to promote gentle boiling during the
subsequent removal of solvents, especially in the case of glass vessels;
8.5.8 Rinse the outside of the neck of the extraction flask with
their use is optional in the case of metal dishes.
a little o
...