Extraction, identification and quantitation of carotenoids in discolored channel catfish (Ictalurus punctatus) fillets

► Lutein, zeaxanthin, alloxanthin, and diatoxanthin were found in discolored fillets. ► Carotenoid content from 58 ng/g for slightly yellow to 215 ng/g for dark yellow. ► Alloxanthin was identified as a main carotenoid in channel catfish for first time.