Quality changes of nile tilapia fillets dipped in phosphate solution and coated with chitosan kept in refrigerated storage

Abstract

Dipping of Nile Tilapia (Oreochromis niloticus) fillets in the mixture solution of 2.0% sodium pyrophosphate and 0.5%sodium triphosphate and coating with 0.0,0.3,0.6,0.9 % chitosan solutions, drained, packed in polyethylene bags, well sealed, stored at 4๐C for 15 days were evaluated. The results showed, the moisture of all sample did not statistically difference and quite constant during storage. The pH and TVB-N value increased with the storage period for all sample, Coating with low concentration of chitosan resulted in lower pH fillets than higher concentration. The decreasing of pH resulted in decreasing of Water Holding Capacity (WHC) of the fillets. Increasing chitosan concentration increased pH and WHC. The oxidation of the samples revealed that the Thiobarbituric acid(TBA) of 0.3% chitosan was maximum and lower with increasing of chitosan concentration. Increasing of TBA may be because of acidity of chitosan solution activated fat hydrolysis. Nevertheless, chitosan coating effectively inhibited growth of microorganism in the fillets.