An Investigation into the Volatile Sulphur Compounds Produced Upon the Heat Treatment of the Hens Egg

An investigation was carried out to examine the volatile sulphur compounds produced upon the heat treatment of the hen's egg. (Gallus gallus domesticus)
A literature survey revealed that the egg had been little studied with respect to the compounds responsible for its unique smell and flavour. The survey also demonstrated the importance of sulphur compounds as flavour volatiles.
The various methods available for collecting volatile flavour compounds from foods have been evaluated to assess their potential usefulness in this study. The most useful method was found to be one of inert gas entrainment followed by selective removal of the sulphur compounds by utilising their ability to form insoluble complexes with mercury salts. Regeneration of the sulphur compounds from the complexes was carried out under reducing conditions by the action of acid, the volatiles being taken up in solvent, n-octane. Separation and detection of the regenerated sulphur compounds were accomplished using a gas chromatograph equipped with a flame ionisation detector. Identification of several volatile sulphur compounds liberated from eggs was made by the use of retention data and mass spectrometry.
Work with model systems indicated the degree of selectivity of the mercury salts used, with respect to their ability to complex sulphur compounds, and the effects that complexing and subsequent regeneration had on the sulphur compounds. These effects were seen to be significant.
Hydrogen sulphide liberated from heat-treated eggs was determined separately by means of an iodimetric/methylene blue method developed for this purpose. The effect of acidity on the methylene blue absorption spectrum was demonstrated. The likely origins of the volatile sulphur compounds determined have been discussed.