Suitability of hybrid tilapia (Oreochromis niloticus x Oreochromis aureus) muscle for gel formation

Lipid oxidation in minced hybrid tilapia muscle and in protein gels prepared from tilapia muscle was investigated. Leaching with water reduced lipid oxidation by 50% in both minced muscle and in protein gels compared with not washing. Lipid oxidation in minced muscle was greatly enhanced (by 40% over 10 days) when ferric ions were added to either the wash water or the minced muscle directly. Frozen storage reduced the rates of lipid oxidation in minced hybrid tilapia muscle and protein gels. Gel strength and deformation of protein gels were not affected by lipid oxidation in minced tilapia muscle. Protein gels prepared with 2.0% or more added NaCl were stronger than those with 1.5% or less added NaCl. Storage of tilapia muscle at -20 degrees C for 4 weeks did not change the rheological property of their protein gels.