BS EN ISO 6321:2021 pdf – Animal and vegetable fats and oils — Determination of melting point in open capillary tubes — Slip point.
1 Scope This document specifies two methods for the determination of the melting point in open capillary tubes, commonly known as the slip melting 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. For the determination of the slip melting point of palm oil samples the method given in Annex A shall be used. 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 documents are referred to in the text in such a way that some or all of their content constitutes requirements of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. ISO 661, Animal and vegetable fats and oils — Preparation of test sample
3? Terms? and? definitions For the purposes of this document, the following terms and definitions apply. ISO and IEC maintain terminological databases for use in standardization at the following addresses: — ISO Online browsing platform: available at https://www.iso.org/obp — IEC Electropedia: available at https://www.electropedia.org/ 3.1 slip melting point in open capillary tube temperature at which a column of fat in an open capillary tube commences to rise under the conditions specified in this document 4 Principle A capillary tube containing a column of the fat which has been crystallized 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 tube is recorded. INTERNATIONAL STANDARD ISO 6321:2021
5 Apparatus Usual laboratory apparatus and, in particular, the following. 5.1 Capillary tubes, having uniform walls and which are open at both ends, of internal diameter 0,9 mm to 1,2 mm, external diameter 1,2 mm to 1,6 mm, wall thickness 0,15 mm to 0,30 mm and length 50 mm to 70 mm 1) . Before use, clean the tubes thoroughly by washing them successively with a mixture of chromic acid, water and acetone or an alternative suitable cleaning solution, for example, hydrogen peroxide can be used. Dry the capillary tubes in an oven. However, it is recommended that new tubes are used. 5.2 Thermometer, graduated in divisions of 0,1 °C, calibrated over the range of melting points expected. 5.3 Stirrer, electrical. 5.4 Cooling bath, filled with brine or other non-freezing liquid, thermostatically maintained at a temperature of −10 °C to −12 °C, or filled with a mixture of flaked ice and salt (in the proportions 2 to 1 by mass) at a temperature of −10 °C to −12 °C. 5.5 Heating apparatus, consisting of the following elements: a) water jacket, made of glass, provided with inlet and outlet tubes, and having the shape and dimensions shown in Figure 1; b) water heater, capable of delivering a slow stream of water, the temperature of which can be controlled to increase at a rate of between 0,5 °C/min and 4 °C/min, through the water jacket [5.5 a)]. An example of a suitable heating apparatus is shown in Figure 2. Other types of heating apparatus, such as a water bath with magnetic stirrer, capable of being controlled to produce the specified temperature rise [5.5 b)], may also be used.