Use of shell colour to infer colour and carotenoid content of the hepatopancreas of the giant river prawn, Macrobrachium rosenbergii (De Man, 1879) (Decapoda, Caridea, Palaemonidae)

Abstract Colour affects the quality and market price of crustaceans, and crustaceans with different hues vary in popularity. However, it is difficult to observe the colour of the internal tissues of live crustaceans with the naked eye. In this study, cooked shells of brown red and dark blue Macrobrachium rosenbergii (De Man, 1879) exhibited higher a *, for redness (20.66 ± 0.34 and 19.25 ± 0.38 vs. 16.82 ± 0.28) and b *, for yellowness (23.39 ± 0.50 and 23.61 ± 0.43 vs. 20.53 ± 0.31) values compared to those of light yellow M. rosenbergii , and the astaxanthin content of the shell showed a similar trend. Blue pigment cells are abundant in dark blue M. rosenbergii , whereas pigment cell development is restricted in light yellow specimens. In brown red individuals, both blue and red pigment cells are abundant. We detected a significant, positive correlation between the a * value of the raw shell and the b * value of the cooked hepatopancreas ( , ); between the a * value of the raw shell and the α -carotene content in the shell ( , ) and β -carotene content in the shell ( , ); and between the b * value of the shell and the astaxanthin content of the hepatopancreas ( , ). The a * ( , ) and b * ( , ) values of the cooked shell also were significantly correlated with astaxanthin content. These results contribute to a more comprehensive understanding of the relationship between shell colour and hepatopancreas coloration and carotenoid content, and they show that the colour of the hepatopancreas can be inferred from the shell colour of M. rosenbergii .