Melanosis inhibition and 4-hexylresorcinol residual levels in deepwater pink shrimp (Parapenaeus longirostris) following various treatments

Abstract

Inhibition of melanosis was studied in pink shrimp (Parapenaeus longirostris) treated on shipboard with various concentrations of 4-hexylresorcinol (4-HR)-based formulations. Treatments, applied by dipping and dusting, were carried out at sea immediately following the catch. A selection of the most effective treatments was made to determine the level of 4-HR residues in the muscle and viscera. 4-Hexylresorcinol proved effective at extending shelf-life over that of untreated shrimp at all the concentrations tested. However, the minimum dose of 4-HR to avoid melanosis for at least one week was found to be 0.5%, with a residual level in muscle ranging from ≈80 to 90 mg/kg at day 2 of storage to >200 mg/kg after 7 days. Residues around 2-3 mg/kg were shown to be effective to prevent melanosis in pink shrimp only for 2 days from a commercial point of view.