Optimization of phosphate treatment process in shrimp for acceptable residual level

Abstract

Seafood industries widely use phosphate dip treatment along with salt to improve the water retention properties of frozen products. Phosphates are GRAS chemical additives with a recommended maximum level of 2,200 mg per Kg in fish and fishery products. Though many combinations are in practise and many researches established different effective combinations, the residue levels were found to be falling out of the limits of regulations. This study optimizes the phosphate dip treatment in Penaeus indicus using Response Surface Methodology to get a safe residue level in the final product. BoxBehnken design with four factors, two levels - phosphate concentration, salt concentration, shrimp to dipping solution volume ratio, and treatment time used to design the experiment. Total phosphorous, weight gain, moisture content, texture and colour properties were investigated as response factors. The suggested models were verified to get a maximum weight gain and safe level of phosphate residue within 7 hrs of treatment. It is concluded that the phosphate residue, within recommended level, is achievable through different combination of initial phosphate concentration, salt concentration, dipping solution volume and treatment time.