Prawnmaster has done significant tests on this. Cooked colour has been part of purchasing techical specifications for decades now.

Refined palm oil is also NOT the solution! Prawn should not support deforestation.

By far the biggest loss in pigmentation is post harvest with chlorine washwater and handling of shrimp.

https://www.globalseafood.org/advocate/it-pays-to-be-pink-farmed-shrimp-production-chain-protects-its-price-points-with-pigmentation/