Simple, Fast and Reliable Determination of Fat in Food According to the Caviezel® Method using a Turnkey Fat Determination System

Significance of the Topic

Accurate determination of fat content in food is essential for quality assurance, regulatory compliance and nutritional labelling. Rapid and reliable analytical methods support production monitoring, labeling accuracy and consumer safety by enabling high-throughput routine testing without compromising data quality.

Study Objectives and Overview

This application note introduces a turnkey system based on the Caviezel® one-step extraction and saponification method followed by GC analysis. The primary goals are to streamline sample preparation, reduce analysis time, and enable simultaneous quantification of total fat and milk fat within a single automated workflow.

Instrumentation

• Sample Preparation Unit: Büchi B-815 with four parallel digestion positions, optimized heating and magnetic stirring program
• Analysis Unit: Agilent GC 7890 coupled to GERSTEL MPS2 autosampler
• Software: GERSTEL MAESTRO for sequence control and integrated reporting of fat content and composition

Methodology

Homogenized samples are weighed into reaction vessels and spiked with internal standards (tridecanoic acid for total fat, valeric acid for milk fat). A mixture of potassium hydroxide and n-butanol is added and refluxed for 30 minutes. The hot extract is acidified with formic acid/dihydrogenphosphate solution to release free fatty acids, followed by phase separation and aliquoting of the organic layer. A predefined 12-minute GC method on a FFAP column with FID detection resolves individual fatty acids, including omega-3 species.

Main Results and Discussion

A calibration strategy using lard and butyric acid standards yields response factors for individual fatty acids. Total fat is calculated as the sum of peak areas normalized to the internal standard. Chromatograms demonstrate efficient separation, with clear distinction of total and milk fat in diverse matrices such as goat cheese (28.3% total fat, 26.3% milk fat), apple-cream cake (26.1%, 28.9%), shrimp cocktail (3.9% milk fat only) and matjes herring (21.0% total fat). Parallel processing of four samples reduces extraction time to 30 minutes, and automated GC analysis completes in 12 minutes per run.

Benefits and Practical Applications

• High sample throughput: parallel extraction accelerates routine testing
• Integrated milk fat determination: valuable for dairy and mixed-product analysis
• Automated workflow: minimal manual intervention and reduced error risk
• Compliance: method aligns with FDA fat definition and labeling requirements

Future Trends and Potential Applications

Advances may include coupling the system with mass spectrometric detection for enhanced fatty acid profiling, miniaturization of sample preparation for lower solvent consumption, and expansion to unsaponifiable lipid fractions. Integration into laboratory information management systems (LIMS) and artificial intelligence-driven data analysis could further streamline quality control processes.

Conclusion

The one-step Caviezel extraction-saponification method combined with automated GC-FID analysis and comprehensive reporting offers a robust, fast and reliable solution for routine fat determination in food and feed matrices. Its capacity to differentiate total and milk fat in a single run makes it a versatile alternative to traditional methods.

References

• Federal Register, 58(3), January 6, 1993, 631–2964