Quality Changes during Frozen Storage of Hot Smoked Fillets and Spreads Processed from Indian Mackerel (Rastrelliger kanagurta) and Pangasius (Pangasius hypophthalmus) Fish

Indian mackerel and Pangasius fish fillets were both subjected to a hot smoking procedure, and their products were used in the spread preparation. Proximate analysis, physicochemical, microbial and sensory properties were monitored before and after frozen storage for three months. The fat content (12.1%) and nutritional value (215.3 Kcal/100g) of the smoked Pangasius fillets were more than those recorded for smoked Indian mackerel fillets (2.5% & 144.1 Kcal/100g, respectively). During frozen storage of smoked Indian mackerel and Pangasius fillets, moisture content was reduced to 61.25 and 51.8%, while an increment was noticed in salt content (2.73 & 2.45%), pH (6.7 & 6.82), TVB-N (24.94 & 18.55 mgN/100g), TBA (2.4 & 2.98 mgMDA/kg), TPC counts (2.5×10³ & 5.3×10³ CFU/g), and yeast and mold counts (0.97×10² & 1.3×10² CFU/g), respectively. Sensory scores for smoked Indian mackerel and Pangasius fillets ranged between very good and good, and the overall acceptability scores became 38 and 35, respectively, at the end of the frozen storage period. By adding feta cheese and ketchup to produce Indian mackerel and Pangasius spreads, the protein content decreased to 21.5 and 19.8%, while carbohydrates (10.2 & 8.5%), fat (4.1 & 13.3%) and nutritional value (163.7 & 232.9 Kcal/100g) increased, respectively. At the end of frozen storage, moisture content decreased to 58.08 and 50.97%, while salt content (3.81 & 2.85%), pH (5.84 & 6.72), TVB-N (33.44 & 23.91 mg N/100g), TBA (2.03 & 2.67 mg MDA/kg), TV counts (7.9×10³ & 9.2×10³ CFU/g), and yeast and mold counts (3.1×10² & 3.8×10² CFU/g) increased, respectively. Sensory scores for the Indian mackerel and Pangasius spreads ranged between very good and good, and the overall acceptability scores became 39 and 37, respectively. The quality of hot smoked fillets and spreads coincides with Egyptian standards for smoked products.