Identification of fake salmon by determination of astaxanthin pigments using high performance liquid chormatography coupled with ultraviolet detector

Abstract

Background: Astaxanthin is a carotenoid produced by different microalgae, bacterias, and yeasts in fish samples. Some fishes like salmon contain astaxanthin in their muscles and it can be a proper indicator for the identification of fishes. Astaxanthin is a carotenoid widely used in salmonid and crustacean aquaculture to provide the pink color characteristic of that species. This application has been well documented for over two decades and is currently the major market driver for the pigment. Additionally, astaxanthin plays a key role as an intermediary in reproductive processes. Synthetic astaxanthin dominates the world market but recent interest in natural sources of the pigment has increased substantially. Aim: The aim of this study was to the identification of fake salmon by determination of astaxanthin pigments using high-performance liquid chromatography coupled with an ultraviolet detector Methods: In this work, a simple and validated method was developed for the determination of astaxanthin in fish samples to the identification of trout from salmon sold in Iranian fish markets. The developed method involved ultrasonic-assisted liquid phase extraction prior to a high-performance liquid chromatography-ultraviolet detector. Results: Under the optimum conditions, analytical features of the method consist of a limit of detection (1.46 ng g-1) and quantification (5.46 ng g-1), linearity (r2=0.9949), precision (RSD≤5.2), accuracy (RSD≤8%), reproducibility (≤2.9), and recovery (98.8%) were acceptable. Conclusion: The method was successfully used to determine the target analytes in several fish samples including thirty salmon produced in Iran, five salmon produced in Norway, and five trout samples. The results showed that trout samples were free of astaxanthin while salmon samples produced in Iran have astaxanthin in the range of 179 ± 9 - 782 ± 40 ng g-1 while the content of astaxanthin is much higher than salmon sample produced in Iran.