An investigation into the fate of sulphites added to hard sweet biscuit doughs

A radiotracer technique, employing [ 35 S]sulphur, has been used to determine the fate of sulphites added to hard sweet biscuit doughs. The results show that about 93% of the sulphur added to the dough as sulphite or metabisulphite remains in the biscuit. This figure is made up of about 30% sulphur as inorganic sulphate and 63% sulphur combined in an organic form; some evidence is presented to suggest that this sulphur may be combined with the biscuit protein as S ‐sulphoprotein. Less than 0.2% of the sulphur remains as inorganic sulphite in the finished biscuit.