An improved and simple method for determining diene conjugation in autoxidized polyunsaturated fatty acids

Area of Science:

• Lipid chemistry
• Oxidation reactions
• Spectroscopic analysis

Background:

• Polyunsaturated fatty acids (PUFA) are susceptible to autoxidation.
• Autoxidation leads to the formation of various degradation products.

Purpose of the Study:

• To investigate the autoxidation of linolenic acid at room temperature.
• To identify and quantify the volatile products of linolenic acid autoxidation.
• To confirm the structural changes in the fatty acid due to oxidation.

Main Methods:

• Autoxidation of linolenic acid using dry air in a rotating apparatus.
• Measurement of malonaldehyde (MDA) production.
• Spectrophotometric analysis (233 nm peak in second derivative spectrum).
• 1H-NMR spectroscopy for structural identification.

Main Results:

• Volatile, thiobarbituric acid-positive products were recovered.
• Malonaldehyde (MDA) production indicated the extent of autoxidation.
• Spectroscopic methods confirmed the formation of conjugated double bonds.

Conclusions:

• Linolenic acid readily autoxidizes at room temperature.
• The study successfully identified and characterized oxidation products.
• 1H-NMR confirmed the structural alterations in the fatty acid backbone.