GB 5009.229-2025 National food safety standard - Determination of acid value in foods
1 Scope
This standard specifies the methods for the determination of acid value in foods.
Method I, Method II, and Method III are applicable to the determination of acid value in foods [except for non-dairy cream, powdered oil, margarine, and compound condiments (mayonnaise, salad dressing, oil-based chili sauce, nut and seed butters, hot pot base, and other semi-solid condiments)].
Method IV is applicable to the determination of acid value in non-dairy cream, powdered oil, margarine, and compound condiments (mayonnaise, salad dressing, oil-based chili sauce, nut and seed butters, hot pot base, and other semi-solid condiments).
Method I Cold solvent indicator titration method
2 Principle
Based on the principle of acid-base neutralization reaction, the free fatty acids in the specimen solution are neutralized with a standard titration solution of potassium hydroxide or sodium hydroxide. The titration endpoint is determined by an acid-base indicator. The acid value of the specimen is calculated based on the consumption of the standard titration solution.
3 Reagents and materials
Unless otherwise specified, analytically-pure reagents and Grade III water (defined in GB/T 6682) are adopted for the purpose of this method.
3.1 Reagents
3.1.1 Isopropanol (C3H8O).
3.1.2 Anhydrous diethyl ether (C4H10O)
3.1.3 95% Ethanol (C2H5OH).
3.1.4 Phenolphthalein (C20H14O4, CAS No.: 77-09-8).
3.1.5 Thymolphthalein (C28H30O4, CAS No.: 125-20-2).
Contents
Foreword i
1 Scope
2 Principle
3 Reagents and materials
4 Apparatus and equipment
5 Analysis steps
6 Expression of analysis results
7 Precision
8 Principle
9 Reagents and materials
10 Apparatus and equipment
11 Analysis steps
12 Expression of analysis results
13 Precision
14 Principle
15 Reagents and materials
16 Apparatus and equipment
17 Analysis steps
18 Expression of analysis results
19 Precision
20 Principle
21 Reagents and materials
22 Apparatus and equipment
23 Analysis steps
24 Expression of analysis results
25 Precision
26 Others
Annex A Removal of impurities and drying/dehydration of oil specimen
Annex B Schematic diagrams for titration endpoint determination in automatic potentiometric titration
