Influence of Brine Salting on the Quality Attributes of Smoke-dried Catfish (Clarias anguillaris) Stored at Ambient Temperature

Abstract

Salting is a method of fish preservation in many countries of the world. It can be used in combination with drying or smoking. Salting of fish removes water and lowers the water activity, thereby reducing the water available to support microbial growth which causes spoilage. The objective of this study is to investigate the influence of brine salting on the quality attributes of smoke-dried catfish (Clarias anguillaris) stored at ambient temperature. The quality attributes of the smoke-dried fish stored for 0-6 weeks at ambient temperature (28 ± 2°C) were evaluated. Smoking was done using a traditional kiln, with charcoal as the source of energy. The proximate composition, total volatile base nitrogen (TVB-N), peroxide value (PV), microbiological and sensory characteristics of smoked catfish were assessed using standard methods. The smoking process reduced the moisture content of catfish from 73.6 to 8.65%, and increased the protein, fat, and ash contents significantly (P ≤ 0.05). The TVB-N of unsalted catfish increased from 4.30 to 36.4mg N/100g within 6 weeks of storage while the PV increased from 1.61 to 24.0 meq g/kg. The TVB-N and PER values for unsalted smoked fish were within the acceptable limit at 4 weeks of storage, but exceeded the limit at 5 weeks. Brine salting reduced the total viable count (TVC) and yeast and mould count (YMC) of the smoked product; the extent of reduction depended on the concentration of brine. A concentration of 6% brine was found to be a suitable level for catfish. The bacteria isolated from the smoked fish samples belonged to the genera Bacillus, Klebsiella Lactobacillus, and Staphylococcus while the fungi belonged to Aspergillus, Fusarium and Penicillium. Sensory scores showed that unsalted smoked catfish stored from 0 to 4 weeks, and the brine salted samples stored from 0 to 6 weeks, had good quality.