SENSORY EVALUATION AND MICROBIAL IDENTIFICATION ON SOME SMOKED FRESHWATER FISH SPECIES TREATED WITH SELECTED VEGETABLE OIL

Abstract

Vegetable oils which are oil extracted from edible plants have been used in a wide range of application in processed food. The study investigated the effect of groundnut, soybean and castor oil treatment on sensory quality, and microbial identification on smoked Clarias gariepinus, Heterotis niloticus and Protopterus annectens. Forty-two (42) fish samples of mean weight of 650g were grouped into batches and immersed in 5% brine solution at ambient temperature of 30±2 °C. The batches were smoked using smoking kiln. Batch (A), the control. B, C and D were immersed in 30 ml, of groundnut, soybean and castor oil respectively. The batches tagged A were the controls from each species of fish. Subscripts 1, 2 and 3 used to indicate fish species from C. gariepinus, H. niloticus and P. annectens respectively. Smoked fish samples were subjected to microbial identification and sensory analysis. Results were subjected to analysis of variance (ANOVA). Significant (p<0.05) difference existed between taste, appearance and odour. The microbes identified include Shigella species, Proteus species, Penicillium species, Rhizopus species, Bacillus species, Aspergillus species, Fusarium species and Mucor species. Appearance recorded highest mean score (6.61) for sample B₁, the least (4.40) appearance was recorded for C₃. Sample B₁ recorded highest (6.00) acceptability, the least (5.00) was recorded for C₂. Oil treatments have shown lower microbial population below control level and have also improved smoked fish sensory parameters. Groundnut oil was most effective in improving the sensory parameters. Soybean oil recorded least microbial identification.