SOP: Determination of Non-Volatile Ether Extract (Fixed Oil) — Spices
GIFSQ — Global Institute for Food Safety & Quality
1. Principle
The spice sample is extracted with petroleum ether, the ether is distilled off and the non-volatile residue is weighed as non-volatile ether extract.
2. Application
This method is applicable to estimate fixed oil in spices having low volatile oil percentage, as well as in the food products with low moisture percentage.
3. Apparatus
- Soxhlet or similar extraction apparatus
- Oven at 110 ± 1°C
- Desiccator containing an efficient desiccant
- Steam bath
4. Reagent
Petroleum ether, A.C.S. grade, anhydrous.
5. Procedure
Take 2 g of sample in the filter paper (Whatman No. 1)
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Put the filter paper with sample in the thimble, plug thimble by means of cotton
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Place the thimble in the Soxhlet
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Extract fat with petroleum ether in a weighed fat flask for 16–20 hours
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Recover petroleum ether through Soxhlet tube
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Evaporate the ether completely from fat flask on the water bath
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Dry in the oven at 100 ± 2°C for half an hour
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The difference between the two final weightings taken at half hour intervals should not be more than 1 mg
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Hold at this temperature until minimum weight is obtained
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The residue is non-volatile ether extract
6. Calculation
Non-volatile ether extract % = [Wt. of NVEE (g) ÷ Wt. of sample (g)] × 100
Note: NVEE = Non Volatile Ether Extract
References
FSSAI (2016), Manual of method of analysis of foods — spices and condiments; Method no 9.0.