ISO 6321 pdf download – Animal and vegetable fats and oils – Determination of melting point in open capillary tubes (slip point).
NOTE 1 If applied to lets with pronounced polymorphism, method A witi give different and less satisfactory resuts ian method B.
NOTE 2 Fats which exhibit prono.xiced polymorpi.sm are pnncipally cocoa butler and lets conta.ng appreciable quantities of 2•unsaturaled. 1,3-saturated triacylglyoerols
2 Normative reference
The following normative document contains provisions which, through reference in this text, constitute provisions of this International Standard. For dated references, subsequent amendments to, or revisions of, this publication do not apply However, parties to agreements based on this International 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. Members of ISO and IEC maintain registers of currently valid International Standards
ISO 661. Animal and vegetable fats and ojls — Preparation of test sanpe
3 Term and definition
For the purposes of this International Standard, the following term and definition apply.
melting point (in open capillary tubes)
s1ip point
temperature at which a column of fat in an open capillary tube commences to rise under the conditions specified in this International Standard
4 Principle
A capillary tube containing a column of the fat which has been crystalkzed under controlled conditions is Immersed to a specified depth in water, the temperature of which is increased at a specified rate, The temperature at which the column is observed to start rising in the capillary tiMe is recorded.
Dip two capillary tubes (5.1) into the melted test sample until columns of tat 10mm ±2 mm long are obtained. Immediately after filling the tubes. wipe them quickly with absorbent tissue to remove any tat adhering to the outer surfaces of the tubes, Immediately place the filled capillary tubes lot 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 mm.
Continue in accordance with 8.3.
8.2 PreparatIon of the capillary tubes for method B
Melt a portion of the test sample as rapidly as possible to at least 5 C, but not more than 10°C. above the temperature at which ii is completely melted.
Cool the melted test sample. wth occasional stirring, until its temperature is 32 °C to 34 °C and then stir continuously with the stirrer (53), allowing the fat to cool until the first signs 01 cloudiness appear.
Continue stirring by hand until the fat has a pasty consistency and then transfer the tat 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 cokimn of fat 10mm ± 2mm 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.
8.3 Determination
8.3.1 AvoidIng transfer ot body heat to the fat, attach two capillary tubes prepared lot method A (8.1) or lot method B (8.2) to the thermometer (5.2) using small rubber bands (or by any other suitable means such as a rubber ring) so that the columns of fat are located at the lower ends of the tubes and lie adjacent to the bulb of the thermometer.
8.3.2 Fill the water jacket (5.5 all and the water heater (5.5 b)j with previously belied water cooled to 15 °C. Clamp or suspend the thermometer with the attached capillary tubes centrally in the water jacket so that the lower ends of the capillary tubes are 30 mm below the surface of the water.
8.3.3 Operate the heating apparatus (5.5)so that a slow stream of water passes through the water jacket, regulating the heating so that the rise in temperature of the water, as measured by the thermometer in the water jacket, is about 3 “C/mm to4 ‘Cmin lot method A and 1 °C/min for method B.
8.3.4 For each of the two capillary tubes, note the temperature value indicated by the thermometer immediately the fat starts to rise in the tube.
8.3.5 Note the arithmetic mean of the two readings obtained. For method A, take this arithmetic mean as the result of one determination.
ISO 6321 pdf download – Animal and vegetable fats and oils – Determination of melting point in open capillary tubes (slip point)
