Antioxidant and antimicrobial potential of water lily extracts and their effects on the quality of frozen Nile tilapia (Oreochromis niloticus) fillets

This study was investigated to evaluate the antioxidant and antimicrobial potential of water lily extracts and their effects on the quality of Nile tilapia (Oreochromis niloticus) fillets during frozen storage (−18 ± 1°C). Antioxidant and antimicrobial activities of water lily extracts, and chemical, microbiological, and sensory qualities of fish fillets were assessed. Results showed that the highest total phenolic content (34.07 mg GAE/g) and total flavonoid content (32.67 mg QE/g extract) were found in the ethanolic extract and the lowest in water extract of water lily. The ethanolic extracts of water lily also exhibited the highest antioxidant capacities and antimicrobial activities than other hydroethanolic and water extracts. The water lily extracts‐treated fish fillets showed the highest potentiality in lowering the pH, total volatile basic nitrogen, and thiobarbituric acid reactive substances than the untreated fillets throughout the storage period. Moreover, ethanolic extracts of water lily exhibited comparatively higher efficacy in inhibiting bacterial growth in fish fillets than other extracts‐treated fillets. The ethanolic extracts‐treated fillets also showed better sensory attributes than hydroethanolic and control fillets. Therefore, ethanolic extract of water lily can be used as a natural preservative in enhancing the quality and prolonging the shelf life of Nile tilapia fillets during frozen storage.