Influence of Chitosan Based Coating Incorporating Green Tea and Rosemary Extracts on Physicochemical and Microbial Quality of Tilapia fish (Oreochromis niloticus) Fillets under Cold Storage


THE incorporation of natural extracts into edible coatings has the potential to improve the quality and safety of fish products. The aim of this work was to evaluate the effectiveness of chitosan coatings including herb extracts against 4 foodborne pathogens;<i> Staphylococcus aureus</i>,<i> Escherichia coli</i>,<i> Bacillus cereus</i>, and <i>Pseudomonas aeruginosa</i>, as well their impact on physical and biochemical attributes of Tilapia fish (<i>Oreochromis niloticus</i>) fillets during storage at 4±1˚C for 15 days. Green tea extract (GTE) and rosemary extract (RE) at concentrations 2 and 3%, respectively were evaluated against foodborne pathogens compared with chitosan coating (control positive; C+) and control sample (without coating; C). The active packaging was applied on Tilapia fish fillets and the physical parameters (pH and WHC), freshness indictors (TBA and TVB-N), microbial load, and sensory evaluation (color, odor, and texture) were evaluated. The GTE and RE exhibited a high phenolic content and antioxidant capacity. In GTE and/or RE coated samples, the values of TBA, TVB-N, and pH were lower while the WHC was higher than the control sample (up to 15 days).The microbial load of treated samples with coatings was lower than the untreated samples. The sensory evaluation of color, odor, and texture in coated fish fillets were accepted with a high score over 15 days. The results demonstrated that GTE and RE were more active in preventing protein degradation, retarding lipid oxidation, improving the microbial quality, and extend shelf life of Tilapia fish fillets.