Effect of polyphosphates on the quality of frozen light salted cod (Gadus morhua L.) fillets

- Injection is a successful method for addition of phosphate in light salted cod.
- Phosphate treatment contributes to a slightly whiter surface.
- Phosphate addition significantly reduces oxidation during frozen storage of light salted cod.
- Phosphates do not affect light salted cod yields or drip loss.
- Light salting of previously frozen materials gives higher yields but inferior quality than from fresh raw materials.

Frozen light salted fillets have been subject to discussion concerning their definition as foodstuff. EU has recently placed these products in the frozen category. The aim was to investigate how a commercial polyphosphate blend affected the quality of light salted fillets. Fresh and previously frozen fillets of cod were injected with a brine containing 0, 4.5, 9 or 18 g/L of Carnal 2110. Quality, chemical characteristics and phosphate residues were analyzed in fillets. Compared to previously frozen, light salted fillets from fresh raw materials had a whither and less yellow color while significantly lower yields and oxidation levels were registered. No differences were found in drip loss during thawing. Addition of polyphosphate contributed to increased whiteness of both frozen and thawed fillets from both raw material groups, while no effects on yields or drip loss were detected. Polyphosphate reduced oxidation only in the frozen raw material group. Total phosphate contents were higher in fillets from fresh than frozen raw materials and residues were mainly detected as monophosphate. The choice of raw material will affect the end quality and yields and results suggest that polyphosphate can improve light salted fillet quality and therefor may be defined as a food additive.