Method development and analysis of retail foods and beverages for carotenoid food colouring materials E160a(ii) and E160e

Abstract

An analytical method using high-performance liquid chromatography with photodiode array detection was developed and applied to the determination of the permitted food colour additives β -carotene (E160a(ii)) and β -apo-8 ′-carotenal (E160e) in foods and beverages. The scope of previously reported methods has been broadened to cover a wide range of retail foods and enzymatic hydrolysis has been used in place of saponification for high-fat samples. Quantitative results (greater then 0.1 mg kg−1) are given for the major colour principals trans- β-apo-8 ′-carotenal and trans-β-carotene. Semiquantitative results are given for the various cis-isomers of each colorant for which authentic reference standards were not available. The method has been used successfully for the analysis of a wide range of foodstuffs with differing fat content without the need for saponification, except for moderate- to high-fat foodstuffs containing significant levels of emulsifiers, for which it was limited. The results suggest that β-apo-8 ′-carotenal (E160e) does not have widespread use in the UK. None of the samples exhibited a total β-carotene content greater than 20 mg kg−1 and none of the high-fat samples and only one of the 17 low-fat/beverage samples contained total β-carotene at levels less than 0.1 mg kg−1. The total β-carotene contents of the low-fat/beverage samples ranged from 0.4 ± 0.03 to 8.4 ± 0.71 mg kg−1, and the total β-carotene contents of the high-fat samples ranged from 0.1 ± 0.01 (jelly confectionery) to 18.5 ± 0.98 mg kg−1 (processed cheese).