Evaluation of tenderness in prawns (Machrobrachium rosenbergii) marinated in various salt and acid solutions

Freshly harvested prawns (Machrobrachium rosenbergii), with shell removed, were marinated in salt (NaCl, CaCl₂) and acid (lemon juice, citric acid, tripolyphosphate) solutions to determine the effects of marination on properties related to the texture of raw and cooked muscle. Sodium chloride and citrate solutions (pH 7.0) slightly increased (P < 0.05) the tenderness of cooked prawn, when compared with water-marination control. Tripolyphosphate (pH 7.0) showed no effect, while CaCl₂ (pH 7.0), citric acid (pH 3.0), and lemon juice (pH 3.0) increased (P < 0.05) the muscle toughness. The decrease of meat tenderness by some of the marinade treatments was attributed to decreases in protein solubility during marination and to cooking losses.