Comparison of red chilli (Capsicum annuum) oleoresin and astaxanthin on rainbow trout (Oncorhyncus mykiss) fillet pigmentation

The effect of dietary carotenoid from red chilli oleoresin and synthetic astaxanthin on the pigmentation of fresh and minced fillet of rainbow trout was compared. Five experimental diets were evaluated: a control diet (CD) containing 80 mg synthetic astaxanthin (Carophyll Pink 8%) kg− 1 diet, two diets containing 80 mg carotenoid kg− 1 diet (HRL1, HRL2), and two diets containing 120 mg carotenoid kg− 1 diet (HRH1, HRH2), each paired with low and high carotenoid containing diets from red chilli oleoresins containing different carotenoid composition and concentration, respectively. The six-week experiment was carried out in a closed recirculation system consisting of ten 3.0 m3 circular tanks containing 161 (150 ± 14 g) rainbow trout. The trout were fed daily at 3% of their total biomass. Results indicated that significant differences existed between fresh and minced fillet colour. Diet HRH2 showed the least colour difference between the fresh and minced fillets, suggesting that the incorporation of 120 mg carotenoid from red chilli oleoresin kg− 1 diet allowed for processing of fillets without significant colour loss. All of the diets produced carotenoid concentrations in trout muscle of more than 5 mg carotenoid kg− 1 muscle at the end of the experimental trial. Colour parameters and carotenoid concentrations in muscle were linearly related.