Extraction of specific egg yolk antibodies and application in chitosan coating: effect on microbial and sensory properties of rainbow trout fillet during chilled storage

BACKGROUND This study investigated the effect of chitosan coating enriched with extracted egg yolk antibodies on microbial and sensory quality of rainbow trout fillet during refrigeration (4 +/- 1 degrees C). Firstly, bacterial antigen suspensions (total psychrophilic bacteria, Pseudomonas fluorescens and Shewanella putrefaciens) were injected into the breast muscles of chickens. Eggs of immunized chickens were then collected to isolate immunoglobulin from egg yolks (IgY). Fresh fish fillets were coated by chitosan solution containing different types of IgY separately, at two concentrations (60 and 90 mg mL(-1)), refrigerated for 16 days and analysed for total viable count, psychrotrophic, Pseudomonas spp., P. fluorescens and S. putrefaciens count as well as sensorial properties. RESULTS The tested microbial values increased in all samples during the storage period; however, CH + IgY treated samples could significantly retard microbial growth compared to control. The shelf life of CH + IgY-P samples was extended for about 4 days, while it was extended for about 8 days in CH + IgY-S and CH + IgY-T samples, when they were compared to control (p < 0.05). Higher scores for sensory attributes were also observed in CH + IgY treated samples, especially in CH + IgY-S samples until the end of storage period. CONCLUSIONS Accordingly, use of chitosan coating containing IgY increases the microbial and sensory quality of fish flesh at 4 degrees C. Therefore, given the consumer interest in natural additives, chitosan coating containing IgY can be a promising candidate. (c) 2018 Society of Chemical Industry