Freshly caught freshwater fish samples of three conventional fishes Clarias gariepinus (Burchell, 1822), Chrysichthys nigrodigitatus (Lacepede, 1803) and Parachanna obscura (Gunther, 1861) were purchased from Asejire Dam in Egbeda Local Government Area of Oyo State Nigeria in April, 2017. Fishes were degutted, washed and processed using steam-cooking, oven-drying, kiln-drying and raw as control. Samples were divided into four equal portions of 500g each and transported in ice to the Central Research Laboratory, Federal University of Technology, Akure for Proximate analysis. Free Fatty Acid was also determined according to the methods of (AOAC, 2005). Crude fat estimation was done using the Folch Method. Minerals were obtained by Dry–ashing the fish samples at 550oC and determined using Atomic Absorption Spectrophotometer (Perkin–Elmer Model 403, Norwalk CT). Potassium was determined by flame photometer (Corning, UK Model 405), [AOAC, 1980] and Phosphorus by vanadomolybdate calorimetric method. Descriptive statistics (mean and standard deviation) were conducted while statistical significance (P < 0.05) was determined by Analysis of Variance (ANOVA) with SPSS version 10. Ducan multiple range test was used to determine significant differences between the means. The results showed that the moisture contents were highest (72.43%) in raw C. gariepinus and lowest (7.23%) in kiln-smoked C. gariepinus. Ash content was highest (9.26%) in kiln-smoked C. gariepinus and lowest (0.89%) in steamed-cooked C. gariepinus. Kiln-smoked C. gariepinus had the highest fat content (29.72%) and raw C. gariepinus recorded the lowest (0.86%) fat. Crude fibre was present in P. obscura and conspicuously absent in other species. Crude protein content ranged from 73.40% in kiln-smoked P. obscura to 17.31% in raw C. nigrodigitatus. Carbohydrate was highest (12.82%) in steamed-cooked C. gariepinus and lowest (0.45%) kiln-smoked C. nigrodigitatus. Free Fatty Acid was highest (1.90%) in steamed-cooked P. obscura but lowest (0.92%) in kiln-smoked C. gariepinus and steamed-cooked C. nigrodigitatus respectively. fibre content was absent in all the species except P. obscura that has low fiber content. the above reveals that moisture, ash, crude protein, fat, fiber, Carbohydrate and Free Fatty Acid were not significantly (p>0.05) affected by the treatment. Minerals contents of all the species subjected to different processing methods were within tolerable levels needed for optimal growth and development. Cadmium was not detected in all the fishes irrespective of processing method. The above reveals that Cu, Fe, Zn, Mg, Ca, and K were not significantly (p<0.05) affected by the processing methods. The Mean value of treatment in C. gariepinus is similar to C. nigrodigitatus but significantly (p<0.05) lesser than P. obscura. Based on the findings of this study, Kiln-smoking is the best processing method and P. obscura has the highest protein content. Its culture could be initiated through research efforts to boosts its availability at affordable price. The finding of this research will be useful to the consumers in choosing fish based on their nutritional values rather than taste, appearance, norms and other physical features.
Keywords: Asejire, Minerals, Processing Methods, Proximate Composition, conventional fishes
