Deterioration of soya-bean oil: quantification of primary flavour compounds using a stable isotope dilution assay.

A stable isotope dilution assay was developed for the quantification of hexanol, (Z)-3-hexenal, 1-octen-3-one, (Z)-1,5-octadien-3-one, 1-octen-3-hydroperoxide, (E)-2-nonenal, (Z)-2-nonenal, (E,Z)-2,6-nonadienal, (E,E)-2,4-decadienal, trans-4,5-epoxy-(E)-2-decenal, and 3-methyl-2,4-nonandione. The oil sample was spiked with the synthesized deuterated internal standards, and the volatile fraction was separated by HPLC. Each fractions isolated was analysed by capillary GC/MS. The procedure was applied to soybean oil samples stored in the presence and absence of light at room temperature. The data obtained were compared with the taste threshold data.