Effects of Clove (Syzygium aromaticum) on the Chemical, Microbiological, Toxicological and Sensory Quality of Smoked and Canned Clarias gariepinus Fillets

Abstract

This study evaluates the effect of incorporating clove (Syzygium aromaticum) into brine (0%, 1%, and 1.5%) on the chemical, microbiological, toxicological, and sensory quality of smoked and canned Clarias fillets. Analyses were performed in triplicate for each treatment. Chemical, microbiological, and toxicological (PAHs) data were processed using SAS software (Statistical Analysis System), with mean comparisons conducted using Duncan's test (p < 0.05); results are presented as mean ± standard deviation. Physicochemical results show a significant decrease in moisture, from 31.81 ± 1.02% in the control to 28.03 ± 1.01% in the batch treated with 1.5% clove, while NaCl content increases from 4.64 ± 0.09% to 6.64 ± 0.03%. The total volatile basic acid (TVB-N) values remain low and comparable between batches (≤ 3.9 ± 1.01 mg/100 g), indicating good freshness of the products. Toxicological analysis (focusing on polycyclic aromatic hydrocarbons (PAHs)) show the absence of benzo(a)pyrene in all samples. Benzo(b)fluoranthene, the major compound, decreases significantly in the 1.5% batch (1.49 ± 0.01 μg/Kg) compared to the control (1.84 ± 0.01 μg/Kg). Similarly, acenaphthene, detected in the control (1.74 ± 0.01 μg/Kg) and the 1% batch (1.44 ± 0.20 μg/Kg), is completely absent in the 1.5% batch. From a microbiological perspective, the total aerobic mesophilic flora is significantly reduced by the addition of clove, dropping from 8.6 × 10⁴ ± 50 CFU/g in the control to 1.2 × 10⁴ ± 90 CFU/g at 1.5%. Yeasts and molds follow the same trend (1.5 × 10⁴ ± 70 to 1.1 × 10³ ± 85 CFU/g), while Salmonella spp., Escherichia coli, and Staphylococcus aureus remain undetected in all batches. The organoleptic analyses conducted on Clarias canned products, however, indicate a clear preference by evaluators for the control product without clove, despite the health benefits observed in the treated batches. Overall, these results demonstrate the potential of farmed smoked Clarias in cans as a way to add value to aquaculture products, providing a sustainable alternative to the overexploitation of wild fishery resources, while also opening up prospects for job creation and the development of local canning units.