Cholesterol, a powerful ¹³C isotopic biomarker

Area of Science:

• Analytical Chemistry
• Biochemistry
• Food Science

Background:

• Cholesterol is a key biomarker for metabolic disorders and a marker for food authentication.
• Analyzing positional ¹³C isotope content in high molecular weight compounds like cholesterol was previously challenging.

Purpose of the Study:

• To develop and validate a novel NMR-based method for determining positional ¹³C isotope contents in cholesterol.
• To assess the utility of cholesterol ¹³C isotopomer analysis for discriminating food origins, specifically hen eggs.

Main Methods:

• Nuclear Magnetic Resonance (NMR) spectroscopy utilizing adiabatic refocused INEPT pulse sequence.
• Optimization of quantitative cholesterol extraction from egg yolk.
• Discriminant analysis using partial reduced molar fractions of ¹³C isotopomers as predictors.

Main Results:

• The study successfully determined positional ¹³C isotope contents in cholesterol for the first time.
• Analysis of ¹³C isotopomer fractions provided enhanced discriminatory power for classifying egg samples by origin compared to global ¹³C composition.
• The optimized method demonstrated the potential for food authentication based on cholesterol isotopomics.

Conclusions:

• Positional ¹³C isotopomer analysis of cholesterol using NMR is a powerful tool for food authentication.
• This methodology offers a significant advancement over traditional isotope ratio monitoring by Mass Spectrometry for sample classification.
• The study establishes a foundation for applying isotopomics to other steroids and complex molecules.