Anti-Oxidative and Anti-fungal Effects of Fresh Ginger (Zingiber officinale) Treatment on the Shelf Life of Hot-smoked Catfish (Clarias gariepinus, Burchell, 1822)

Abstract

Ginger is a rhizome with an established medicinal value. This study seeks to explore its anti-oxidative and anti-fungal properties when added to fish prior to smoking. An experiment was conducted to determine the effectiveness of ginger (Zingiber officinale) spice mixture on the shelf-life of hot-smoked Clarias gariepinus at different concentrations {0 g of ginger kg-1 of fish (control), 10 g of ginger kg-1 of fish, 20 g of ginger kg-1 of fish and 30 g of ginger kg-1 of fish}. Retardation in lipid oxidation, microbial proliferation and organoleptic qualities were used to assess the efficacy of ginger as an anti-oxidant and anti-fungi in hot-smoked catfish. The fish were divided into four batches and coated with appropriate quantities of ginger paste to give concentrations of 0 g of ginger kg-1 fish, 10 g of ginger kg-1 fish, 20 g of ginger kg-1 fish and 30 g of ginger kg-1 fish. They were then smoked for 8 h, cooled and stored in ambient temperature (25-30°C) for 21 days. Chemical, microbial and sensory evaluation studies were carried out on them. The anti-oxidative activity of ginger was evident from lower Thio Barbituric Acid (TBA) and peroxide values of treated samples relative to untreated (control) samples. The lowest TBA (2.88±0.35) and peroxide (5.87±1.48) values were recorded in 30 g of ginger kg-1 of fish while the highest TBA (4.08±0.51) and peroxide (13.38±1.97) occurred in the control. The results also showed that samples treated with ginger paste had lower microbial load than the control. Ginger has anti-oxidative and anti-fungal properties which can extend the shelf-life of hot-smoked Clarias gariepinus.