Stability study of smoked fish, horse mackerel (Trachurus trachurus) by different methods and storage at room temperature

Abstract

The present study assessed the effect of hot smoke using wood and charcoal dry heat on keeping quality of Trachurus trachurus fish fillet, skin, head and bones (SHB). T. trachurus was smoked using the altona kiln at 80 to 105°C for eight hours, placed in cain woven baskets to cool off, packaged in sealed transparent polythene bags and left on shelf for 7 days at ambient temperature (32 ± 2°C). Biochemical indexes assayed were: pH, total volatile nitrogen (TVBN), peroxide value (PV) and total viable count (TVC). pH of raw T. trachurus fillet was 6.85 ± 0.00 but significantly reduced with wood smoke at day 0 to 6.70 ± 0.02, while TVBN in raw T. trachurusfillet was 27.17 ± 1.61 mgN/100 g. After smoking, TVBN of T. trachurus fillet at day 0 was 21.83 ± 0.38 mgN/100 g (wood) and 23.05 ± 1.36 mgN/100 g (charcoal). pH of raw T. Trachurus SHB was 5.87 ± 0.03 and increased (p<0.05) with smoking, that is, 6.43 ± 0.21 (wood) and 6.43 ± 0.00 (charcoal). TVBN in the raw T. Trachurus SHB was 28.12 ± 2.17 mgN/100 g, and after smoking on day 0, it was 31.90 ± 0.3 mgN/100 g (wood smoked) and 24.44 ± 1.90 mgN/100 g (coal smoked). The PV was highest in charcoal smoked SHB (CSHB) of T. trachurus at day 5(108.40±36.80) and TVC was highest in the CSHB on day 5 (3.48 logcfu/g). The overall study showed that T. trachurus fish samples (fillet and SHB) prepared via charcoal smoking method had the lowest (p<0.05) storage time amongst the smoked fish samples, when compared with those that were processed via wood smoke. Key words: Trachurus trachurus, ambient temperature, smoked fish and seafood quality.