GB/T 5530-1998 Determination of acid value and acidity of animal and vegetable fats and oils

This standard specifies two methods for the determination of free fatty acids in animal and vegetable fats and oils - the indicator method and the potentiometer method. This standard applies to animal and vegetable fats and oils, not waxes. GB/T 5530-1998 Determination of acid value and acidity of animal and vegetable fats and oils GB/T5530-1998 Standard download decompression password: www.bzxz.net

GB/T5530-1998
GB/T5530-1998
This standard is a revision of GB5530-85 "Animal and vegetable fats and oils - Determination of acid value and acidity" based on the international standard ISO660:1983 "Animal and vegetable fats and oils - Determination of acid value and acidity". It is equivalent to the international standard in terms of technical content. Compared with GB5530-85, it adds the potentiometric titration method and the use of acidity to express the free fatty acid content. The preparation and expression of the standard are in accordance with the requirements of GB/T1.1-1993 "Guidelines for standardization work Unit 1: Rules for drafting and expressing standards Part 1: Basic provisions for the preparation of standards". This standard was proposed by the Ministry of Domestic Trade of the People's Republic of China. The drafting unit of this standard: Cereal Oil Chemistry Research Institute of the Ministry of Domestic Trade. The main drafters of this standard: Hao Xicheng, Liu Jing, Ying Shanhong. ISO Foreword
ISO (International Organization for Standardization) is a world federation composed of national standardization bodies (ISO member bodies). The development of international standards is carried out by ISO technical committees. All member groups interested in the standards projects established by a technical committee have the right to participate in the work of the committee. International organizations (official or unofficial) that maintain contact with ISO may also participate in the relevant work. Before the draft international standard adopted by the technical committee is approved by the ISO committee as a formal international standard, it must be submitted to the member groups for approval.
International standard ISO660 was developed by ISO/TC34 Agricultural Food Technical Committee and sent to member groups in September 1982.
Adopted by the member bodies of the following countries:
Australia
Portugal
Ethiopia
New Zealand
Bulgaria
Israel
Malaysia
Austria
Philippines
The member bodies that disapproved of this document on technical grounds are: Netherlands
Canada
Tanzania
Mexico
Hungary
Yugoslavia
This International Standard replaces and cancels ISO Recommendation R6601968 after revising its technical content. Approved by the State Administration of Quality and Technical Supervision on May 8, 1998 and implemented on December 1, 1998
GB/T5530-1998
National Standard of the People's Republic of China
Animal and vegetable fats and oils-Determination of acid value and of acidity
Animal and vegetable fats and oils-Determination of acid value and of acidityGB/T5530-1998
eqvISO660:1983
Replacement: GB5530-85
This standard specifies two methods for the determination of free fatty acids in animal and vegetable fats and oils, namely the indicator method and the potentiometer method. This standard applies to animal and vegetable fats and oils, but not to waxes. 2 Referenced Standards
The provisions contained in the following standards constitute the provisions of this standard through reference in this standard. When this standard is published, the versions shown are valid. All standards are subject to revision, and parties using this standard should explore the possibility of using the latest versions of the following standards.
GB/T15687—1995 Preparation of oil and fat samples (eqvISO661:1989) 3 Definitions
This standard adopts the following definitions.
3.1 Acid value
The number of milligrams of potassium hydroxide required to neutralize 1g of free fatty acids in oil and fat. 3.2 Acidity
The percentage of free fatty acids in oil and fat. The types of fatty acids in oil and fat are shown in Table 1
Types of oil and fat
Coconut oil, palm kernel oil and oils with high lauric acid content
Other oils
Types of fatty acids
Fatty acids expressed
Lauryl oil
Molar mass, g/mol
Note: When the result is written as "acidity" without detailed explanation, this "acidity" is usually expressed in terms of oleic acid. 4 Indicator titration method
4.1 General situationbZxz.net
This method is more suitable for oils and fats that are not very dark in color. 4.2 Principle
The sample is dissolved in a mixed solvent of ether and ethanol, and then the free fatty acids present in the oil and fat are titrated with a potassium hydroxide-ethanol standard solution.
4.3 Sample
The reagents listed in this standard are all analytically pure, and the water is distilled water. 4.3.1 Ether (HG3-1002) and 95% ethanol (GB679) solvents are mixed in a volume ratio of 1:1. Before use, 0.3mL of the indicator (4.3.3) is accurately neutralized with potassium hydroxide ethanol solution (4.3.2) for every 100mL of the mixed solvent. Approved by the State Administration of Quality and Technical Supervision on May 8, 1998, and implemented on December 1, 1998
GB/T5530-1998
Warning: Ether is highly flammable and can generate explosive peroxides. It must be used with extreme caution. Note: Toluene can replace ethanol: Isopropyl alcohol can replace ethanol if necessary. 4.3.2 Potassium hydroxide (GB2306) 95% ethanol standard solution, c(KOH) = 0.1 mol/L or c(KOH) = 0.5 mol/L if necessary
The exact concentration of the solution must be known before use and should be calibrated. Use the solution prepared at least five days ago. Transfer the clear solution to a brown glass bottle for storage and seal it with a rubber stopper. The solution should be colorless or light yellow. 4.3.3 Phenolic acid (GB10729) Indicator solution: 10 g/L 95% ethanol solution. 4.4 Instruments
4.4.1 Analytical balance: sensitivity 0.0001g. 4.4.2 Conical flask: 250mL.
4.4.3 Burette: 10mL, minimum scale 0.05mL. 4.5 Analysis steps
4.5.1 Sample preparation
Perform according to GB/T15687.
4.5.2 Sample
According to the estimated acid value, sample according to Table 2
Table 2 Sample sampling table
Estimated acid value
Sample amount, g
Put the accurately weighed sample into a 250mL conical flask (4.4.2). 4.5.3 Determination
Accurate value of sample weight, g
Add the sample (4.5.2) to 50-150 mL of pre-neutralized ether-ethanol mixture (4.3.1) and dissolve it. Titrate with 0.1 mol/L potassium hydroxide solution (4.3.2) while shaking until the indicator shows the end point (the phenolic acid turns pink and needs to remain for at least 10 seconds without fading). Note: If the volume of 0.1 mol/L potassium hydroxide solution required for titration exceeds 10 mL, a potassium hydroxide solution with a concentration of 0.5 mol/L can be used.
4.5.4 Number of determinations
The same sample is determined twice.
5 Potentiometric titration
5.1 Principle
In anhydrous medium, methyl ethyl propylene glycol solution is used to titrate the free fatty acids in the sample by potentiometric titration. 5.2 Reagents
The reagents listed in this standard are all analytically pure, and water is distilled water. 5.2.1 Methyl isobutyl ketone
Before use, use potassium hydroxide-isopropanol solution (5.2.2) to accurately neutralize until the phenol indicator endpoint turns slightly red. 5.2.2 Potassium hydroxide-isopropanol (HG3-1167) standard solution, c(KOH) = 0.1 mol/L or c(KOH) = 0.5 mol/L. The exact concentration of the solution must be known before use and should be calibrated. 5.3 Instruments
5.3.1 150 mL tall beaker.
Approved by the State Administration of Quality and Technical Supervision on May 8, 1998, implemented on December 1, 1998
GB/T5530-1998
5.3.2 10 mL burette, minimum scale 0.05 mL. 5.3.3 pH meter with glass and calomel electrodes. The saturated potassium chloride solution and the sample solution must be in contact with each other using a sintered glass or porcelain disk with a minimum thickness of 3 mm.
5.3.4 Magnetic stirrer.
5.4 Analysis steps
5.4.1 Sample preparation
Perform according to GB/T15687.
5.4.2 Sample
Weigh 510 g of sample, accurate to 0.01 g, and place it in a beaker (5.3.1) 5.4.3 Determination
Dissolve the sample (5..4.2) in 50 mL of methyl isobutyl ketone (5.2.1). Insert the electrode of the pH meter (5.3.3), start the magnetic stirrer (5.3.4), and use potassium hydroxide-isopropanol solution (5.2.2) Titrate to the equivalence point.
5.4.4 Number of determinations
The same sample is determined twice.
6 Expression of analysis results
6.1 Acid value
Acid value=V×c×56.1
Where: V is the volume of the potassium hydroxide standard solution used, mL; c is the exact concentration of the potassium hydroxide standard solution used, mil/L; m is the mass of the sample, g;
56.1 is the molar mass of potassium hydroxide, g/mil. 6.2 Acidity
Acidity can be calculated from the results of acid value determination, whether it is the indicator method or the potentiometer method. Acidity (%)_V×cxM
Where: V is the volume of potassium hydroxide standard solution used, mL; c is the accurate concentration of potassium hydroxide standard solution used, mil/L; M is the molar mass of the acid selected to express the result, gmol/L; m is the mass of the sample, g;
The arithmetic mean of the two measurements is taken as the measurement result. 7. Test report
The test report should indicate the method used and the results obtained, and clearly indicate the expression method used. The operating conditions not specified in this standard should also be described in detail. And the details that may affect the results should be explained. The test report should include all the information required for sample identification. Approved by the State Administration of Quality and Technical Supervision on May 8, 1998 and implemented on December 1, 1998.
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