1 Scope
This standard specifies methods for the determination of acidity of animal and vegetable fats and oils (two titrimetric and one potentiometric) for the determination of acidity in animal and vegetable fats and oils. The acidity is expressed preferably as acid value.
The hot ethanol determination method is the reference method. The cold solvent method described is applicable to light-color fats and oils.
The methods are not applicable to waxes.
2 Normative References
The following normative documents contain provisions which, through reference in this text, constitute provisions of this standard. For dated references, subsequent amendments to (excluding amending errors in the text), or revisions of, any of these publications do not apply. However, all parties coming to an agreement according to this standard are encouraged to study whether the latest edition of the normative document is applicable. For undated references, the latest edition of the normative document applies.
GB/T 6682-1992 Water for Laboratory Use; Specifications (neq ISO 3696:1987)
GB/T 15687 Oils and Fats - Preparation of Test Sample (GB/T 15687-1995, eqv ISO 661:1989)
3 Terms and Definitions
For the purposes of this International Standard, the following terms and definitions apply.
3.1
Acid value
Number of milligrams of potassium hydroxide required to neutralize the free fatty acids present in 1g of oil and fat, when determined in accordance with the method specified in this standard; it is expressed in milligrams per gram.
3.2
Acidity
Content of free fatty acids determined according to the method specified in this standard, which is expressed as a percentage by mass.
Foreword II
1 Scope
2 Normative References
3 Terms and Definitions
4 Hot Ethanol Method Using Indicator
4.1 General
4.2 Principle
4.3 Reagents
4.4 Apparatus
4.5 Sampling
4.6 Preparation of Test Sample
4.7 Procedure Portion
5 Cold Solvent Method
5.1 General
5.2 Principle
5.3 Reagents
5.4 Apparatus
5.5 Sampling
5.6 Preparation of Test Sample
5.7 Procedure
6 Potentiometric Method
6.1 Principle
6.2 Reagents
6.3 Apparatus
6.4 Sampling
6.5 Preparation of Sample
6.6 Procedure
7 Calculation
7.1 Acid Value
7.2 Acidity
8 Precision
8.1 Repeatability
8.2 Reproducibility
9 Test report
Annex A (Informative) Results of Interlaboratory Tests
Bibliography
