Salt Acclimation of Freshwater Prawns and Its Effects On Consumer Acceptance

Freshwater prawns (Macrobrachium rosenbergii) naturally inhabit brackish water habitats, but pond culture in North America occurs in freshwater. Post-harvest acclimation of live freshwater prawns to water with marine salt mixtures increases consumer acceptability. The high cost of marine salt mixtures typically prohibits their use in commercial practice.  This study examined survival and consumer acceptability of post-harvest freshwater prawns subject to temporary salt acclimation (NaCl, NaCl/KCl/CaCl₂ and marine salt) or marination treatments (NaCl).  Freshwater treatments were divided into non-marinated controls and two post-mortem marination treatments (shell and no shell).  Three consumer panels (n=60 per replication) were conducted to assess the acceptability of prawns.  Changes in the concentrations of salt and molecular flavor enhancers were determined and correlated to changes in preference.  Survival was lowest in solar salt (NaCl, 67%) and highest in freshwater (95%) followed by marine salts (85%) and CaCl₂ (73%).   All salt acclimation treatments were preferred over the freshwater control.  The flavor, texture and overall acceptability of post-mortem marination without the shells were preferred over all other treatments. These data suggest that post-mortem marination or salt acclimation adds value to freshwater prawns. Post-mortem marination offers a viable alternative to salt acclimation decreasing mortality losses.