Analysis of Sterols in Butter Fat

Significance of the topic

Sterols such as cholesterol and phytosterols are essential biomarkers in dairy products for nutritional assessment, quality control and authentication. Profiling sterol content in butter fat supports detection of adulteration and verification of labeling claims.

Objectives and Study Overview

This application note (AN0054) presents a gas chromatography–flame ionization detection (GC-FID) method optimized for resolving and identifying eight target sterols in butter fat. The goal is to deliver a reliable, reproducible workflow for routine laboratory use.

Methodology

Butter fat samples were analyzed by injecting 0.8 µL on-column into a GC fitted with a 30 m × 0.32 mm × 0.25 µm SCION-5MS capillary column. The temperature program starts at 115 °C (1 min), ramps to 260 °C at 9 °C/min, then to 290 °C at 1.5 °C/min. Helium at 100 kPa was used as carrier gas, and detection was performed with an FID set to 320 °C.

Used Instrumentation

• SCION GC-FID system
• SCION-5MS capillary column (30 m × 0.32 mm × 0.25 µm)
• On-column injector module
• Helium carrier gas supply

Main Results and Discussion

The method achieved clear separation of eight sterols: cholestane, cholesterol, brassicasterol, campesterol, stigmasterol, β-sitosterol, stigmastanol and ianosterol. Retention times were consistent and peak shapes were sharp, demonstrating effective chromatographic resolution under the chosen temperature program.

Practical Benefits and Applications

This GC-FID protocol offers a fast, cost-effective approach for sterol profiling in the dairy industry. It supports routine QA/QC, authenticity testing and nutritional analysis with minimal sample preparation and standard instrumentation.

Future Trends and Opportunities

Emerging techniques such as GC–MS and comprehensive two-dimensional GC can further enhance sensitivity and resolution. Supercritical fluid chromatography provides greener alternatives, and coupling with chemometric data analysis can improve discrimination of complex dairy matrices.

Conclusion

The optimized GC-FID method described here delivers reliable identification and quantification of major sterols in butter fat. Its simplicity and robustness make it a valuable tool for quality control laboratories.

References

• SCION Instruments. Application Note AN0054: Analysis of Sterols in Butter Fat.