A liquid chromatographic method for the estimation of Class III caramel added to foods

An ion-pair high-performance liquid chromatographie (HPLC) method has been developed and validated for the estimation of Class III caramel added to foods. The method is based on measurement of a component of the caramel that has been found in all Class III caramels analysed to date and is considered to be a characteristic marker substance. The abundance of this component is correlated to the amount of ammonia incorporated into the caramel. Since the nitrogen content of Class III caramels from different manufacturers and different formulations varied over a 2.3-fold range, whilst still described as Class III caramels, this variability in the composition of the food additive limits the HPLC method quantitatively to a relative standard deviation of 38%. ety of beers, biscuits, gravy powders, savoury spreads, confectionery products and baked foods were tested using the method. There were no false positives and no false negatives. The limit of detection of the method was 0.1 g litre−1 for beers and 0.3 g kg−1 for solid foods. For biscuit samples supplied by manufacturers with a known caramel content, analysis found 38–92% of the caramel concentration declared by the manufacturer. For beers, the values were 34–78%. Since the analytical recovery from biscuits and beers spiked with caramel and analysed immediately was typically 100 ± 10%, this is taken as evidence that the marker component is only partially stable during the manufacture, packaging and storage of the foods. Indirect support for this postulate was the finding that 3-year-old caramels (ex. 1990) contained on average only 34% of the marker substance compared to fresh (ex. 1993) caramels after allowance was made for the nitrogen content. More controlled stability trials are underway. It is concluded, therefore, that the HPLC method provides a simple, robust and semiquantitative measure of the presence of Class III caramel in foods.