Canthaxanthin (E 161g) is a type of carotenoid pigment with an orange-red colour. It occurs naturally in many foods such as mushrooms, crustaceans, fish and eggs. The pigment has also been produced by synthetical means.
Canthaxanthin is primarily used as a feed additive for animals. It can lead to a more intensely coloured egg yolk and flesh from poultry, and a more reddish colour for salmon. It is authorised for use as a feed additive in the EU for the sole purpose of colouring food. The provisions of Council Directive 70/524 control its use, where an authorised concentration for complete feedingstuffs for salmonids and poultry is given.
An acceptable daily intake (ADI) of 0.03 mg canthaxanthin per kg of body weight has been established in the EU by the Scientific Committee on Food (SCF) and The Joint FAO/WHO Expert Committee on Food Additives (JECFA). The EU Scientific Committee on Animal Nutrition (SCAN) has expressed the opinion that the ADI may be exceeded by high consumers of salmonid and/or poultry products, and has therefore suggested that the maximum concentration of canthaxanthin allowed in feedingstuffs be reduced.
As a consequence of the SCAN opinion, the EC may propose revised maximum concentrations for canthaxanthin in feedingstuffs which is likely to increase demand for the determination of carotenoid concentrations in feeds. If Trading Standards Departments, via Public Analysts, are to enforce any revised Regulations prescribing maximum limits for canthaxanthin (and associated carotenoids), then a validated analytical method must be available. The objective of this project is to provide such a validated method.
The approach taken for this project is as follows:
The identification of sources of carotenoid standards. To include:
- The identification of reliable sources of carotenoids.
- The identification of traceable E1%1cm values/extinction coefficients for the carotenoids identified.
- The prescription of a protocol for the determination of the concentration of carotenoid standards.
- Obtaining commercial carotenoid feed additives to examine chromatographic purity.
- Obtaining salmonoid and poultry feed samples from feed manufacturers.
The HPLC Separation of All Carotenoids of interest. Salmonid and poultry feed samples obtained will be taken through the LGC ISO 17025 accredited saponification and extraction procedure, and the extracts examined by HPLC. The chromatograms will be examined to establish if there are any potential matrix interferences (i.e. compounds that elute at carotenoid retention times).
The extraction and recovery of carotenoids from feedingstuffs and foods (also estimation of repeatability and trueness). To include:
- The recovery of canthaxanthin standards from salmonid and poultry feed.
- The recovery of canthaxanthin from foods.
- The recovery of ‘associated carotenoid’ standards from salmonid and poultry feed.
- The recovery of ‘associated carotenoid’ standards from foods assessment of the trueness of the procedure.
To expose the developed method for the determination of canthaxanthin and related carotenoids in feeds and food to collaborative Trial according to IUPAC guidelines.