Effects of riboflavin-photosensitization on the formation of volatiles in linoleic acid model systems with sodium azide or D 2O

Abstract

Effects of riboflavin-photosensitization on volatile formations were studied in linoleic acid model systems with sodium azide or D 2O. Linoleic acid with riboflavin solution were stored under light or in the dark and volatiles were analyzed by a combination of solid phase microextraction (SPME), gas chromatography (GC), and mass spectrometry (MS). Riboflavin-photosensitization produced 27.9% more total volatiles than samples stored in the dark for 16 h. Addition of sodium azide decreased the total volatiles by 28.4% compared to samples without sodium azide. Linoleic acid in D 2O had higher increases in total volatiles than samples in H 2O system. Decrease of total volatiles in samples with sodium azide and increase of total volatiles in D 2O sample indirectly showed the presence of singlet oxygen in riboflavin-photosensitization. Hexanal, 2-heptenal, 1-octen-3-ol, 2-octenal, and 2,4-decadienal were greatly influenced by the addition of sodium azide and in D 2O, which indicates that formation of these volatiles was related to singlet oxygen oxidation. Especially, 2-heptenal showed the highest peak area among volatiles under riboflavin-photosensitized linoleic acid for 16 h.