Combined effects of lactoperoxidase system-whey protein coating and modified atmosphere packaging on the microbiological, chemical and sensory attributes of Pike-Perch fillets

The present study aimed to evaluate the efficacy of lactoperoxidase system-whey protein coating and modified atmosphere packaging (60% CO2, 30% N-2, 10% O-2) combination (LPOS + WPS + MAP) on the microbiological, chemical and sensory specifications of Pike-Perch (Sander Lucioperca, Linnaeus 1758) fillets. The highest bacterial count was observed in the fish fillets packaged with whey protein coating solutions (WPS) in compare with the other groups. Combination of WPS + LPOS and MAP packaging could significantly inhibit bacterial growth. Total volatile basic nitrogen (TVB-N), as a quality index of flesh, had strong correlation (r = 0.98-0.99) with microbial load, so that the highest and the lowest TVB-N values were observed in WPS and WPS + LPOS + MAP batches, respectively. Assessments of thiobarbituric acid reactive substances index showed that incorporation of LPOS with WPS or MAP did not have remarkable effect on lipid oxidation, but combined effect of MAP and WPS + LPOS on reducing fat oxidation was significant. The pH values in WPS + LPOS, WPS + MAP and WPS + LPOS + MAP were significantly lower than WPS. Sensory evaluations indicated that LPOS + WPS + MAP kept Pike-Perch fillets at high sensory acceptability for at least 16 days in refrigerated temperature. In conclusion, combination of MAP and WPS + LPOS showed synergistic effects on shelf-life extension of Pike-Perch fillets under refrigerated storage.