Some changes in an aqueous liquid smoke flavouring during storage in polythene receptacles

Aqueous liquid smoke produces a brown layer on the wall of the polythene receptacle in which it has been contained. The constituents of this brown layer have been extracted using dichloromethane and were studied by means of gas chromatography/mass spectrometry (GC/MS) and Fourier transform infrared spectroscopy (FTIR). Some changes in the liquid smoke were deduced through comparisons of data from the brown layer with the previously obtained liquid smoke data. Due to interactions between polythene molecules and compounds of the liquid smoke, some of these latter compounds migrate into the wall of the receptacle and are retained there. The extent of these migrations depends on the size of the hydrocarbon part of each compound. However, far from being harmful, this migration is useful, since compounds irrelevant from the point of view of flavour, and harmful to health are the main compounds affected by the retention on the polythene wall. Some of the adsorbed compounds have not previously been reported to be present in liquid smoke.