Method development and analysis of retail foods for annatto food colouring material

Abstract

Analytical methods for the determination of the permitted food colouring annatto (E160b) have been developed or refined to encompass the wide range of food commodity types permitted to contain it. Specific solvent extraction regimens have been used depending upon the food commodity analysed and HPLC analysis techniques coupled with spectral confirmation have been used for the determination of the major colouring components. Qualitative and quantitative data on the annatto content of 165 composite and two single retail food samples covering a wide range of foods at levels above the limit of quantification (0.1mg kg−1) is reported. Quantitative results are given for the major colour principals 9′-cis-bixin, 9′-cis-norbixin andtrans-bixin. Semi-quantitative results are given for the minor bixin and norbixin isomers monocis- (not 9′-), di-cis- andtrans-norbixin, for which authentic reference standards were not available. Repeat analyses (n = 4−9) of 12 different types of food commodity (covering the permitted range) spiked with annatto at levels between 1.7 and 27.7 mgkg−1 gave mean recoveries between 61 and96%. The corresponding relative SDs (RSD) were between 2.1 and7.9%.