Antioxidant effect of Citrullus vulgaris (watermelon) extract against lipid oxidation in fish during cooking
The Antioxidant effect of Citrullus Vulgaris (Watermelon) extract was evaluated against lipid oxidation in freshly caught fishes during cooking. GC-MS analysis of Hexane and total phenolic extract of Citrullus Vulgaris flesh reveals that the extracts contain 55 compounds which includes 5- hydroxymethyl furfural, 4H-Pyran-4-one, 2,3-dihydro-3,5-dihydroxy-6-methyl-, Hexadecanoic acid, ethyl ester and Palmitic acid ester that are reported as antioxidants. Muscle flesh of fifteen (15) samples of freshly caught fish comprising Group I (Tilapia zilli; n=5), Group II (Clarias hollandis; n=5) and Group III (Clarias gariepinus; n=5) were prepared and Sub Grouped each as Control, Treatment 1, Treatment 2, Treatment 3 and Treatment 4 which receives 0, 50, 150, 250 and 450mg of Citrullus Vulgaris extract per 100g fresh fish muscle weight respectively. Treatment 4 gave the highest protection against lipid oxidation in all groups, however the concentration of MDA in Treatment 3 of Group I and III were not significantly (p>0.05) higher as compared to Treatment 4 of same Groups. The results clearly suggested that the extract effectively prevented lipid oxidation in fish and that the rate of prevention is a factor of fish species and extract concentration.
Keywords: Fish, citrullus vulgaris, lipid oxidation, Antioxidants, Malondialdehyde (MDA)