Preliminary study on the antioxidative and anti-fungal effects of ginger oil on the shelf life of hot smoked fish

Abstract

The antioxidative and anti-fungal effects of ginger oil on smoked Chrysichthys nigrodigitatus, Clarias gariepinus and Oreochromis niloticus were examined during five week storage at room temperature 25-30°C. The ginger oil was extracted from fresh ginger through hydro-distillation. The fish samples were gutted washed thoroughly and each fish species were divided into three groups. Two groups were spiced with 1.0 and 1.5 mL of ginger oil/kg of fish, respectively before they were smoke dried for 2 h. The third group acts as the control which was not spiced with ginger oil. Chemical and microbiological analyses were performed to investigate quality changes and to determine the shelf stability of the products. The lowest TBA (14.64 mg MDA kg• 1) and peroxide (3.91 mEq kg• 1) values were recorded in Oreochromis niloticus samples treated with 1.5 mL ginger oil/kg of fish at week 1, while the highest TBA (30.48 mg MDA kg• 1) and PV (18.76 mEq kg• 1) occurred in the Clarias gariepinus control at week 5. The result also revealed that samples treated with ginger oil had lower mould count than the control but there was no significant different (p• 0.05), when compared to the control after 5 weeks of storage.