Comparative Evaluation of Microbial Load, Sensory Quality, And Fatty Acid Profile of Smoked-Dried Silver Catfish (Chrysichthys Nigrodigitatus) Treated with Ginger and Turmeric Processed with Rice Husk Briquettes

Abstract

This study evaluated the effects of ginger (Zingiber officinale) and turmeric (Curcuma longa) on the microbial load, sensory properties, and fatty acid profile of smoked-dried silver catfish (Chrysichthys nigrodigitatus) processed using rice husk briquettes as smoking fuel. Fresh samples of silver catfish were divided into four treatment groups: control (without spices) treated with ginger, turmeric, and a combination of both spices before smoking and drying with rice husk briquettes. The treated fish samples were stored under ambient conditions and analyzed periodically for microbial quality, sensory acceptability, and fatty acid profile composition. Results revealed that spice-treated samples recorded significantly lower microbial counts compared to the control samples throughout storage. The turmeric-treated samples maintained the lowest microbial loads (1.7 × 10⁴ CFU/mL bacteria; 3.8 × 10⁴ CFU/mL fungi), exhibited the strongest antimicrobial activity, resulting in reduced total viable count and fungal growth. Sensory evaluation showed that turmeric and combined ginger + turmeric significantly improved appearance, aroma, taste, texture, colour, and overall acceptability of smoked silver catfish. Spice-treated samples had superior organoleptic qualities compared to the control. Fatty acid analysis indicated better preservation of essential unsaturated fatty acids in spice-treated samples, Oleic acid content ranged from approximately 28.50–31.20%, while linoleic acid ranged from 14.80–17.40% in treated samples, compared to lower values in the control, with reduced lipid oxidation and lower free fatty acid accumulation during storage. The use of rice husk briquettes provided efficient smoking conditions and acceptable sensory qualities comparable to traditional smoking fuels while promoting environmental sustainability. The study concluded that ginger and turmeric can serve as effective natural preservatives in smoked-dried silver catfish, enhancing microbial safety, sensory quality, and fatty acid stability during storage.