Background and Objectives: Nowadays, diverse methods are used for  protection and increasing the shelf life of aquatic products and thermal drying is one of them. In the present study chemical indices and fatty acid composition of Grass Carp is investigated as affected by thermal drying.

Materials & Methods: The samples were dried within 4-24 hrs in a laboratory dryer at 65^°C and stored under Air-pack conditions at 4°C. Temperature and time were recorded until moisture reduced to 40%. Changes of Nutritional value and qualitative indices such as TVB-N, PV, TBA, FFA and Fatty acids profile were studied.

Results: Due to moisture loss, amounts of protein (16.01 to 31.15 %), ash (1.60 to 6.41%) and lipid (4.30 to 13.62%) were increased in the dried product (P<0.05). In addition, amounts of pH 6.21 to 6.61, TVB-N 3.21 to 27.27 mg/100g, PV 0.86 to 6.37 meqO₂/Kg and TBA 0.045 to 1.256 mgMDA/Kg and FFA 0.45 to 1.79 % were increased in the dried fish (P<0.05). Omega-3 (2.29 to 2.15 g/100g), Omega-6 (13.24 to 16.18 g/100g) and sum of EPA+DHA fatty acids (1.78 to 1.06 g/100g) were changed.

Conclusion: All of qualitative chemical indices were changed during storage in cold- storage but dried products had acceptable quality during 30 days storage at 4°C.