Evaluation of antioxidant properties of Chlorella vulgaris and Spirulina platensis and their application in order to extend the shelf life of rainbow trout (Oncorhynchus mykiss) fillets during refrigerated storage

The present study was undertaken to evaluate the antioxidant effect of alcoholic extract of Chlorella vulgaris and Spirulina platensis on extending the shelf life of rainbow trout (Oncorhynchus mykiss) fillet in 4 ± 1°C. The experiments were performed on 5 samples (1 blank and 4 treatments) and in triplicate. The results from DPPH and FRAP assays represents the higher antioxidant activity of Chlorella (42.96% and 0.33) at concentration of 200μg/ml and Spirulina (62.46% and 0.41; 77.12% and 0.46) at concentrations of 400 and 600μg/ml, respectively. The results from performed chemical tests compared to the blank sample showed that samples treated with algae extracts were able to control the increase in these parameters. Among the treated samples, maximum control of peroxide value, thiobarbituric acid and free fatty acid, respectively pertained to the treatments containing 0.1% of Spirulina (3.14, 2.93 and 2.25) and Chlorella (3.21, 3.06 and 2.28) extracts. The results of sensory evaluation showed that except the sample containing 0.05% of Chlorella, in other samples containing the algae extract, less negative effects on color, odor, texture and taste were observed. Consequently, Chlorella and Spirulina extracts can delay lipid oxidation process and maintain or improve sensory properties of refrigerated fish.