The effect of different types of chitosan on the chemical characteristics of huso fillet (Huso huso) stored in refrigerator

The aim of this study was to investigate the effect of chitosan as a natural preservative. Farmed fish were washed and filleted. In this study, 3 types of chitosan were investigated: acid-soluble chitosan, water-soluble chitosan and oligosaccharide chitosan. The fillets were immersed in the above solutions for 30 seconds, and then removed, and after 2 minutes, the immersion was repeated. Control samples were uncovered. The fillets were then placed at room temperature (20 °C) for 2 hours to form a coating on the fillets. 192 pieces of 100 g fish fillets were divided into 4 treatments and each treatment was divided into 4 times: treatment one as a control (without preservative), the second treatment containing 1% acid-soluble chitosan, the third treatment containing 1% water-soluble chitosan and the fourth treatment containing 1% Chitosan oligosaccharides. All samples were stored in refrigerator at 4±1 °C and their chemical parameters (Peroxide, pH, Thiobarbituric acid, Total Volatile Nitrogen) were measured on (0, 4, 8 and 12) days. All the indices of treatments had increasing trend over time. Only in the pH index of 1% acid-soluble chitosan had an irregular trend. 1% acid-soluble chitosan had the most positive effect in all treatments. Due to increase in chemical indices in all treatments, the addition different of chitosans to fish fillets could prevent or reduce them.