GB/T 5539-2026Inspection of grain and oils - Qualitative test of oils (English PDF)
粮油检验 油脂定性试验
Open the GB/T 5539-2026 preview as PDF
This is a limited preview
Buy now to download the full PDF (7 pages)
Issued by
SAMR; SAC
Level / Type
National · Recommended
Issue date
July 30, 2026
Implementation date
February 1, 2027
Scope
GB/T 5539-2026 is the English-translated version of 粮油检验 油脂定性试验.
This document describes qualitative methods of detection for vegetable oils and fats, and applies to the detection of tung oil, castor oil, linseed oil, mineral oil, sesame oil and cottonseed oil. It supersedes GB/T 5539-2008, which also covered purity tests and the detection of soybean, peanut, rapeseed, camellia, hemp seed and tea seed oils and of lard.
Document preview — GB/T 5539-2026
National Standard of the People's Republic of China
- ICS
- 67.200.10
- Classification
- X 14
- Replacing
- GB/T 5539-2008
Issued by: State Administration for Market Regulation; Standardization Administration of China
Contents
- Foreword1
- 1 Scope1
- 2 Normative references1
- 3 Terms and definitions1
- 4 Qualitative tests of oils1
- 4.1 Detection of tung oil1
- 4.2 Detection of castor oil2
- 4.3 Detection of linseed oil2
- 4.4 Detection of mineral oil2
- 4.5 Detection of sesame oil3
- 4.6 Detection of cottonseed oil3
1 Scope
This document describes qualitative methods of detection for vegetable oils and fats.
It applies to the detection of tung oil, castor oil, linseed oil, mineral oil, sesame oil and cottonseed oil.
2 Normative references
The contents of the following documents constitute indispensable provisions of this document through normative reference in the text. For dated references, only the edition corresponding to that date applies. For undated references, the latest edition, including all amendments, applies.
GB/T 6682 Water for analytical laboratory use - Specification and test methods · GB/T 22515 Grain and oils terminology - Grain, oilseeds and their products
3 Terms and definitions
The terms and definitions given in GB/T 22515, together with the following, apply to this document.
mineral oil: base oil refined from petroleum by physical distillation.
4.1 Detection of tung oil
Reagent: concentrated sulfuric acid, analytical grade.
Apparatus: white spot plate, with six, nine or twelve wells.
Procedure: place a few drops of the well-mixed sample in a well of the white spot plate, add one or two drops of concentrated sulfuric acid and observe the change of colour.
Interpretation: a deep red solid whose colour deepens gradually and turns black after 15 min to 20 min shows that tung oil is present; the deeper the colour, the higher its content. The method is suitable for detecting tung oil at contents above 0.5 %.
4.2 Detection of castor oil
Reagents: potassium hydroxide and magnesium chloride, both analytical grade.
Apparatus: flat-bottomed nickel crucible 4 cm in diameter and 3.5 cm high, and a balance readable to 0.01 g.
Procedure: weigh about 1.00 g of the well-mixed sample into the nickel crucible, add 0.03 g to 0.10 g of potassium hydroxide, heat slowly until it melts and smell it. Alternatively, dissolve the melt in water, add an excess of magnesium chloride to precipitate the fatty acids, filter and observe whether the filtrate is turbid.
Interpretation: a smell of octanol in the first procedure, or a turbid filtrate in the second, shows that castor oil is present. The method is suitable for detecting castor oil at contents above 0.5 %; it does not apply to the detection of castor oil in peanut oil.
4.3 Detection of linseed oil
Reagents: diethyl ether, analytical grade; bromine solution, made by adding enough bromine to carbon tetrachloride to increase the volume of the solution by half, that is to 1.5 times the original volume.
Apparatus: 20 mL stoppered colorimetric tube, 100 microlitre to 1 000 microlitre micropipette and 10 mL measuring cylinder.
Procedure: pipette 0.5 mL of the well-mixed sample into the 20 mL stoppered colorimetric tube, add 10 mL of diethyl ether and 3 mL of bromine solution, stopper once dissolved, mix by inversion, bring the solution to 25 degrees Celsius and observe for 2 min. At the same time run a control on a normal sample free of linseed oil.
Interpretation: turbidity within 2 min shows that linseed oil is present. The method is suitable for detecting linseed oil at contents above 0.5 %; it does not apply to the detection of linseed oil in walnut oil, olive oil or sesame oil.
4.4 Detection of mineral oil
Reagents: water to grade three of GB/T 6682; absolute ethanol and potassium hydroxide, both analytical grade; aqueous potassium hydroxide solution made by adding 15 g of potassium hydroxide, weighed to 0.01 g, to 10 mL of water.
Apparatus: water bath covering room temperature to 99.9 degrees Celsius, straight condenser, 250 mL ground-joint conical flask matching the condenser, 10 mL and 25 mL measuring cylinders, 1 mL micropipette and a balance readable to 0.01 g.
Procedure: weigh 1.00 g of the well-mixed sample to 0.01 g into the ground-joint conical flask, add 1 mL of the potassium hydroxide solution, 25 mL of absolute ethanol and two to four boiling stones, connect the reflux condenser and reflux in a water bath at about 97 degrees Celsius for about 5 min, shaking continuously until saponification is complete. Then add 25 mL of boiling distilled water to the flask at once, shake and observe immediately.
Interpretation: marked turbidity, or oily matter separating out, shows that mineral oil is present in the sample. The method is suitable for detecting mineral oil in vegetable oils and fats whose wax ester content is below 0.5 %, with a lower detection limit of 0.5 %. It does not apply to the detection of mineral oil in crude rice bran oil or in sea buckthorn seed oil.
4.5 Detection of sesame oil
Reagents: concentrated hydrochloric acid, analytical grade; 2 % furfural in ethanol, made by adding 2 mL of furfural to 95 % ethanol and making up to 100 mL.
Apparatus: 25 mL colorimetric tube, 10 mL and 25 mL measuring cylinders, 20 microlitre to 200 microlitre micropipette and 100 mL volumetric flask.
Procedure: measure 5 mL each of the well-mixed sample and of concentrated hydrochloric acid into the colorimetric tube, add 0.1 mL of the 2 % furfural solution, shake for 30 s to mix thoroughly, let stand for 10 min and observe the colour; where a deep red, red or pink colour appears, add 10 mL of water, shake again for 30 s and observe the colour. Dark oil samples may be bleached with alkali, the alkali and the water then being removed completely from the oil; where necessary a bleached sample containing sesame oil may be used as a control.
Interpretation: if the deep red, red or pink colour disappears, no sesame oil is present; if it does not disappear, sesame oil is present. The method is suitable for detecting sesame oil at contents above 0.25 %. It does not apply to the detection of sesame oil in olive oil.
4.6 Detection of cottonseed oil
Reagents: water to grade three of GB/T 6682; 1 % sulfur powder in carbon disulfide, made by mixing 1 g of sulfur powder into 100 mL of carbon disulfide; pyridine or amyl alcohol, analytical grade; and saturated brine.
Apparatus: 25 mm by 150 mm test tube, thermostatic water bath and 10 mL and 25 mL measuring cylinders.
Procedure: measure 5 mL each of the well-mixed sample and of the 1 % sulfur powder solution into the test tube, add two drops of pyridine or amyl alcohol, shake to mix, place in a bath of saturated brine and heat slowly until the brine begins to boil; after 40 min take the tube out and observe the change of colour.
Interpretation: a deep red or orange-red colour shows that cottonseed oil is present; the deeper the colour, the higher its content. The method is suitable for detecting cottonseed oil at contents above 0.5 %. It does not apply to the detection of cottonseed oil in dark oils such as sesame oil and crude corn oil.
......
This preview omits tables, figures, formulas and parts of the technical clauses. The complete document — 7 pages — is available in the English PDF.
Referenced standards
Normative references
- GB/T 6682 Water for analytical laboratory use - Specification and test methodsWater for analytical laboratory use - Specification and test methods
- GB/T 22515 Grain and oils terminology - Grain, oilseeds and their productsTerminology of grain and oil - Grain and oil-bearing material and their prouducts
Similar standards
Editions of GB/T 5539
| Edition | Title | Revision | Status |
|---|---|---|---|
| GB/T 5539-2026 | Inspection of grain and oils - Qualitative test of oils | second revision | Current |
| GB/T 5539-2008 | — | first revision | Superseded |
| GB/T 5539-1985 | — | first issue | Superseded |
This page sells the current edition, GB/T 5539-2026. Earlier editions are listed for reference only.
How to Buy GB/T 5539-2026
- 1Add to cart. Click the "Buy GB/T 5539-2026" button on this page. You can add more standards before checkout.
- 2Checkout. Enter your email and billing details. Payment is processed securely by Stripe (cards, Apple Pay, Google Pay supported).
- 3Instant delivery (0–9 sec). Delivery is automatic: within seconds of payment you'll receive an email with a secure download link. The link stays valid for 72 hours.
- 4Invoice included. A tax invoice is attached to the confirmation email. Need a custom invoice? Contact us.
Related Standards
GB/T 47310-2026 — Determination of total silicon, aluminium, iron, potassium, sodium, calcium, magnesium, manganese, phosphorus, titanium and sulfur in soil - Monochromatic excitation energy dispersive X-ray fluorescence spectrometry
GB/T 47321-2026 — Specification for the warning data exchange of the national emergency early warning dissemination system
GB/T 47293-2026 — Determination of available mercury in soil
Secure payment via Stripe
Payments accepted
GB/T 5539-2026
$270.00