Liquid Chromatography-Atmospheric Pressure Photo Ionization-Mass Spectrometry Analysis of the Nonvolatile Precursors of Rancid Smell in Mayonnaise

Abstract

Monitoring lipid oxidation during the shelf life of lipid-containing food emulsions, such as mayonnaise, is challenging. It is, however, essential for the development of improved, consumer-preferred products. Determining the nonvolatile lipid oxidation products (NONVOLLOPS), the precursor compounds for rancidity, is required to determine the effectiveness of product stabilization technologies. A method based on normal-phase liquid chromatography with atmospheric pressure photo ionization-mass spectrometry (LC–APPI-MS) was developed for this purpose. The inclusion of a size-exclusion chromatography (SEC) step was needed to remove interfering diacylglycerides and free fatty acids from the samples. The combined SEC and normal-phase LC–APPI-MS method allowed the identification of a wide range of oxidized species including hydroperoxides, oxo-2½ glycerides, epoxides, and other oxidized species. The method was found to be more suitable for the analysis of large sample sets. The relative levels of NONVOLLOPS from both ambient and accelerated stability tests could be determined. The results were compared to hexanal measurements. The data showed that NONVOLLOPS predict the rancidity of different formulations in a much earlier stage during shelf-life tests, providing valuable information for future product development