Probe Electrospray Ionization mass spectrometry for analysis of lipid oxidation in food

PETROSELLI GABRIELA; MANDAL MRIDUL; HIRAOKA KENZO; HIROSHI NONAMI; ERRA BALSELLS ROSA

Takamatsu

Congreso; Environmental Control in Biology; 2013

Lipid oxidation in foods constitutes a complex chain of reactions that yields to primary products (peroxides), which once exposed to extended oxidation conditions, give rise to secondary oxidation products, including aldehydes, ketones, epoxides and hydroxy compounds. Most of these secondary oxidation products produce undesirable sensorial and biological effects. To avoid rancidification process oils should be stored in a cold and dark environment. The oxidation process becomes more pronounced with the higher number of double bonds in lipids. Despite being intermediate compounds of lipid oxidation process, hydroperoxides are relatively stable (depending on the lipid structure) and can be used to assess lipid oxidation status in food samples, as long as the sample is not in an advanced oxidative status. Because of this feature, temperature conditions during analysis must be controlled to avoid hydroperoxide decomposition and addition of an antioxidant is often required. The probe electrospray ionization (PESI) is an ESI-based ionization technique that generates electrospray from the tip of a solid metal needle. This technique is versatile in the analysis of biological samples as it requires only a small amount of the material picked up without any special sample preparation. Methanolic extract of several nuts were chosen for the investigation of oxidation process, as it contains highly insaturated lipids. The sample was exposed to air and sunlight for several days. PESI mass spectra were recorded before and after treatment. Moreover, statistical analysis was used to compare PESI mass spectra of nut, soybean, macademia nut and peanut.