GB/T 24892-2010Animal and vegetable fats and oils -- Determination of melting point in open capillary tubes (slip point) (English PDF)

Foreword

This Standard is identical to ISO 6321:2002, Animal and vegetable fats and oils –

Determination of melting point in open capillary tubes (slip point) (English version).

This Standard is identical to the translation of ISO 6321:2002.

For ease of use, this Standard has made the following editorial changes:

a) Change the expression "this International Standard" to "this Standard";

b) Use a decimal point "." instead of a comma "," as a decimal point;

c) Delete the "Foreword" of international standard;

d) Use GB/T 15687-2008 Animal and vegetable fats and oils – Preparation of test

sample to replace ISO 661:2003 Animal and vegetable fats and oils – Preparation

of test sample.

Annex A of this Standard is a normative annex, and Annex B is an information annex.

This Standard is proposed by the State Grain Administration.

This Standard is under the jurisdiction of the National Technical Committee 270 on

Grain and Oil of Standardization Administration of China.

The drafting organization of this Standard: National Grain Administration Research

Institute.

1 Scope

This Standard specifies two methods for the determination of the melting point in open

capillary tubes, commonly known as the slip point, of animal and vegetable fats and

oils (referred to as fats hereinafter).

-- Method A is only applicable to animal and vegetable fats which are solid at

ambient temperature and which do not exhibit pronounced polymorphism.

-- Method B is applicable to all animal and vegetable fats which are solid at ambient

temperature, and is the method to be used for fats whose polymorphic behaviour

is unknown.

A method for the determination of the melting point of palm oil samples is given in

Annex A.

Note 1: If applied to fats with pronounced polymorphism, method A will give different

and less satisfactory results than method B.

Note 2: Fats which exhibit pronounced polymorphism are principally cocoa butter and

fats containing appreciable quantities of 2-unsaturated, 1,3-saturated

triacylglycerols.

2 Normative references

The following normative document contains provisions which, through reference in this

text, constitute provisions of this Standard. For dated references, subsequent

amendments to, or revisions of, this publication do not apply. However, parties to

agreements based on this Standard are encouraged to investigate the possibility of

applying the most recent edition of the normative document indicated below. For

undated references, the latest edition of the normative document referred to applies.

GB/T 15687, Animal and vegetable fats and oils - Preparation of test sample (GB/T

15687-2008, ISO 661:2003, IDT)

3 Term and definition

For the purposes of this Standard, the following term and definition apply.

Melt a portion of the test sample as rapidly as possible to at least 5 °C ~ 10 °C above

the temperature at which it is completely melted.

Dip two capillary tubes (5.1) into the melted test sample until columns of fat 10 mm ±

2 mm long are obtained. Immediately after filling the tubes, wipe them quickly with

absorbent tissue to remove any fat adhering to the outer surfaces of the tubes.

Immediately place the filled capillary tubes for a few seconds against a beaker filled

with ice so that the fat solidifies. Place the tubes in the cooling bath (5.4) for 5 min.

Continue in accordance with 8.3.

34 °C and then stir continuously with the stirrer (5.3), allowing the fat to cool until the

first signs of cloudiness appear.

Continue stirring by hand until the fat has a pasty consistency and then transfer the fat

to a 100 mL beaker at 17 °C ± 2 °C. Store the fat at this temperature for a minimum of

24 h.

Push four capillary tubes (5.1) into the conditioned fat until a column of fat 10 mm ± 2

mm long is obtained in each tube. Wipe the tubes quickly with absorbent tissue to

remove any fat adhering to the outer surfaces of the tubes. Store the tubes at 17 °C ±

2 °C until required.