Büchi, represented by Labotec in South Africa, introduces innovative technologies for precise fat determination in oil and fat products.
Pressurised Liquid Extraction (PLE) is a well-established alternative for extracting lipids and/or various components faster and cheaper, but less frequently used for the verification of fat labels in food products.
Fat determination using pressurised liquid extraction (PLE)
A reliable and fast procedure using PLE to determine the fat content in samples with easily accessible fat is presented below. The extraction was carried out using the SpeedExtractor E-916 in combination with Multivapor P-12 for solvent evaporation in parallel. The fat content was determined gravimetrically after the extract has been dried to a constant weight.
Experimental setup: Instrumentation: SpeedExtractor E-916, Multivapor™ P-12 with Vacuum pump V-700 and Controller V-855, drying oven – Samples: Mayonnaise and chocolate (Round robin test MCL-3/2011) – Temperature: 100°C – Pressure: 100 bar – Solvent: n-Hexane 90%; Ethanol 10% – Total extraction time: 42 minutes
Results: The fat content of mayonnaise and chocolate showed: – Chocolate: Expected 40.62 g/100g, Experimental 40.84 g/100g (0.26% RSD) – Mayonnaise: Expected 79.03 g/100g, Experimental 79.29 g/100g (0.30% RSD)
Conclusion: The determination of the fat content in food samples by PLE using SpeedExtractor E-916 provides reliable and reproducible results that correspond to the expected values. This method increases the sample throughput and is more environmentally friendly due to less solvent consumption compared to Soxhlet extraction.
Using Twisselmann extraction for salad dressing samples
Method overview: The Twisselmann extraction is performed with the Extraction Unit E-816 ECE (Economic Continuous Extraction). This allows the sample to be constantly kept in hot solvent vapor whilst being efficiently rinsed with freshly distilled solvent.
Sample types tested: French dressing diet (declared: 13.0 g/100g) – Italian dressing (declared: 20.4 g/100g) – Italian dressing diet (declared: 0.5 g/100g) – French dressing with herbs (declared: 41.0 g/100g) – Italian dressing Toscana with herbs (declared: 44.0 g/100g) – French dressing diet with herbs (declared: 7.0 g/100g)
Key parameters: Solvent: Petroleum ether – Extraction time: 50 minutes – Drying time: 10 minutes – Total time: 60 minutes – Solvent volume: 70 mL
Results summary: The fat contents determined with Twisselmann extraction were comparable to Soxhlet extraction results, with relative standard deviations below 2%.
Reliable fat measurements via hot extraction
Procedure overview: A simple and fast procedure for determination of edible oil and fat products using the Extraction Unit E-816 for Hot Extraction. Samples are first dried with sodium sulfate anhydrous and mixed with sand before extraction.
Sample types: Diet Mayonnaise (declared: 34g/100g) – Herbal butter (declared: 62g/100g) – Mayonnaise (declared: 72g/100g) – Margarine (declared: 80g/100g) – Sunflower oil (declared: 92g/100g)
Extraction parameters: Solvent: Petroleum ether 40-60°C – Extraction step: 5 minutes (Heater 100%) – Rinse step: 30 minutes (Heater 100%) – Drying step: 5 minutes (Heater 100%) – Total time: 40 minutes – Solvent volume: 65 mL
Results: All determined fat contents were within expected values with relative standard deviations below 1%.
