GB/T 15688-2024 Animal and vegetable fats and oils-Determination of insoleole impurities content
1 Scope
This document specifies a method for the determination of the insoluble impurities content of animal and vegetable fats and oils.
This document is applicable to animal and vegetable fats and oils. If it is not desired to include soaps (particularly calcium soaps) or oxidized fatty acids in the insoluble impurities content, it is necessary to use a different solvent and procedure to make the determination meet relevant requirements.
Milk and milk products (or fat coming from milk and milk products) are excluded from the scope of this document.
2 Normative reference
The following referenced documents are indispensable for the application 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
Note: GB/T 15687-2008 Animal and vegetable fats and oils - Preparation of test sample (ISO 661:2003, IDT)
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
insoluble impurities content
quantity of dirt and other foreign matter insoluble in n-hexane or light petroleum under the conditions specified in this document
Note 1: The content is expressed as a percentage by mass.
Note 2: These impurities include mechanical impurities, mineral substances, carbohydrates, nitrogenous substances, various resins, calcium soaps, oxidized fatty acids, fatty acid lactones, and (in part) alkali soaps, hydroxy-fatty acids and their glycerides.
4 Principle
A test portion is treated with an excess of n-hexane or light petroleum, then the solution obtained is filtered. The filter and residue are washed with the same solvent, then dried at 103℃ and weighed.
5 Reagents
WARNING - Attention is drawn to the regulations which specify the handling of dangerous substances. Technical, organizational and personal safety measures shall be followed.
5.1 n-Hexane or light petroleum, having a distillation range between 30℃ and 60℃ and having a bromine value of less than 1. For either solvent, the residue on complete evaporation shall not exceed 0.002 g per 100 ml.
5.2 Kieselgur, purified, calcinated, with loss in mass at 900℃ (red heat) of less than 0.2% by mass.
5.3 Use only reagents of analytical grade.
