Rapid Determination of Sulphur Dioxide in Foods

ide in Foods M. W. Kr.lnsrpy euo A. TnaNos National College of Food Technology, University of Reading, St George’s Avenue, Weybridge, Surrey A rapid method for suJphur dioxide estimation in foods is described. The method uses a compact, semi-automatic distillation apparatus normally used for nitrogen estimation, and gives a much reduced analysis time compared with those of conventional methods, whilst the apparatus design reduces operator attention and error. Typical analysis times are 3 min for jams and soft- drinks, and 12 min for sausages. Introduction Sulphur dioride (SOr) is used extensively as a preservative in the food industry to prevent and control microbial spoilage. It is used in its gaseous or liquid form, or dissolved in water to form sulphur- ous acid, or in the lorm olits acid or neutral salts the sulphites, bisulphites and metabisulphrtes. In addition to its anti-microbial role, sulphur dioxide will also inhibit non-enzymic and enzymic browning and help in the preservative action ol ascorbic acid: but adverseiy it causes cleavage of thiamine and may give rise to “off’flavours and odours, and cause bleaching in high concentrations. Sulphur dioxide inhibits the growth