Effects of specific egg yolk antibody (IgY) on the quality and shelf life of refrigerated Paralichthys olivaceus

Microencapsulation of immunoglobulin Y: optimization with response surface morphology and controlled release during simulated gastrointestinal digestion

Immunoglobulin Y (IgY) is an effective orally administered antibody used to protect against various intestinal pathogens, but which cannot tolerate the acidic gastric environment. In this study, IgY was microencapsulated by alginate (ALG) and coated with chitooligosaccharide (COS). A response surface methodology was used to optimize the formulation, and a simulated gastrointestinal (GI) digestion (SGID) system to evaluate the controlled release of microencapsulated IgY. The microcapsule formulation was optimized as an ALG concentration of 1.56% (15.6 g/L), COS level of 0.61% (6.1 g/L), and IgY/ALG ratio of 62.44% (mass ratio). The microcapsules prepared following this formulation had an encapsulation efficiency of 65.19%, a loading capacity of 33.75%, and an average particle size of 588.75 μm. Under this optimum formulation, the coating of COS provided a less porous and more continuous microstructure by filling the cracks on the surface, and thus the GI release rate of encapsulated IgY was significantly reduced. The release of encapsulated IgY during simulated gastric and intestinal digestion well fitted the zero-order and first-order kinetics functions, respectively. The microcapsule also allowed the IgY to retain 84.37% immune-activity after 4 h simulated GI digestion, significantly higher than that for unprotected IgY (5.33%). This approach could provide an efficient way to preserve IgY and improve its performance in the GI tract.

Application an edible active coating based on chitosan- Ferulago angulata essential oil nanoemulsion to shelf life extension of Rainbow trout fillets stored at 4 °C

The present study was undertaken to evaluate the feasibility of nanoemulsification for improving the efficiency of chitosan- Ferulago angulata essential oil coating (CH + EO) on extending the shelf life of Rainbow trout fillets during 16 days storage at 4 °C. The average droplet size of coarse emulsions was dramatically reduced after nanoemulsification which was accompanied by a significantly more positive ζ-potential and lower polydispersity index. In vitro antibacterial potential of CH + EO against two fish specific spoilage organisms, Shewanella putrefaciens and Pseudomonas fluorescens, and its antioxidant activity improved significantly (p < 0.05) when nanoemulsions were fabricated. The CH + EO nanoemulsion (3% EO) treatment exhibited a significantly better inhibitory effect on bacterial growth of refrigeration stored Rainbow trout fillets. Moreover, nanoemulsification potentiated the efficacy of CH + EO in retarding the increase of TVB-N and lipid peroxidation in fish fillets. Texture, colour, and overall acceptability of CH + EO nanoemulsion treated samples were significantly (p < 0.05) better than those of other samples. Results suggest nanoemulsification as a potential approach to enhance the efficacy of the active coating.

Quantitative Analysis of Cold Stress Inducing Lipidomic Changes in Shewanella putrefaciens Using UHPLC-ESI-MS/MS

Shewanella putrefaciens is a well-known specific spoilage organism (SSO) and cold-tolerant microorganism in refrigerated fresh marine fish. Cold-adapted mechanism includes increased fluidity of lipid membranes by the ability to finely adjust lipids composition. In the present study, the lipid profile of S. putrefaciens cultivated at 30, 20, 10, 4, and 0 °C was explored using ultra-high-pressure liquid chromatography/electrospray ionization tandem mass spectrometry (UHPLC-ESI-MS/MS) to discuss the effect of lipid composition on cold-adapted tolerance. Lipidomic analysis detected a total of 27 lipid classes and 606 lipid molecular species in S. putrefaciens cultivated at 30, 20, 10, 4, and 0 °C. S. putrefaciens cultivated at 30 °C (SP-30) had significantly higher content of glycerolipids, sphingolipids, saccharolipids, and fatty acids compared with that at 0 °C (SP-0); however, the lower content of phospholipids (13.97%) was also found in SP-30. PE (30:0), PE (15:0/15:0), PE (31:0), PA (33:1), PE (32:1), PE (33:1), PE (25:0), PC (22:0), PE (29:0), PE (34:1), dMePE (15:0/16:1), PE (31:1), dMePE (15:1/15:0), PG (34:2), and PC (11:0/11:0) were identified as the most abundant lipid molecular species in S. putrefaciens cultivated at 30, 20, 10, 4, and 0 °C. The increase of PG content contributes to the construction of membrane lipid bilayer and successfully maintains membrane integrity under cold stress. S. putrefaciens cultivated at low temperature significantly increased the total unsaturated liquid contents but decreased the content of saturated liquid contents.

Rainbow trout fillet biopreservation by edible chitosan-based coating containing egg yolk antibody (IgY) and lycopene

The aim of the study was to investigate the effect of the extracted egg yolk antibody along with lycopene on the chemical quality of the rainbow trout fillet during 16 days of refrigeration storage. Chickens were immunized against Pseudomonas fluorescens (P. fluorescens), Shewanella putrefaciens (S. putrefaciens) and total spoilage bacteria and their eggs were collected for the isolation of egg yolk antibodies. Then fish fillets were immersed in chitosan-based coating solutions, containing lycopene and extracted antibodies, and analyzed for lipid oxidation changes (peroxide, thiobarbituric acid, free fatty acid and fatty acid profile), physico-chemical properties (pH and water holding capacity), and sensory evaluation, during 16 days of refrigeration storage. Results showed that chitosan solutions with lycopene or IgY could significantly (p < 0.05) increase the oxidative stability of lipids in fish fillets; although, combinational use of lycopene and IgY showed a higher effect on delaying the rate of lipid oxidation. Significant differences were also observed between treatments contained combination of chitosan, antibody and lycopene with the control group, regarding pH and WHC. Saturated fatty acids increased in all treatments, although the changes in the treatments containing lycopene and antibody were significantly (p < 0.05) lower than the control group. Hence the addition of egg yolk antibody and lycopene in coating solution are good bio-preservatives for seafood products as it improves sensory attributes and prevents lipid oxidation.

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 °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 °C. Therefore, given the consumer interest in natural additives, chitosan coating containing IgY can be a promising candidate. © 2018 Society of Chemical Industry.

The preparation and antibacterial effect of egg yolk immunoglobulin (IgY) against the outer membrane proteins of Vibrio parahaemolyticus

BACKGROUND

Vibrio parahaemolyticus causes not only various diseases in aquaculture animals but also seafood-borne illness in humans. Outer membrane proteins (OMPs) are species-specific proteins found in bilayer membranes of gram-negative bacteria. Egg yolk immunoglobulin (IgY) has been reported to serve as oral administration of antibodies against bacteria and virus.

RESULTS

The present research extracted and identified OMPs from V. parahaemolyticus, and then the extracted OMPs were used to immunize hens to obtain specific IgY. The efficacy of IgY against V. parahaemolyticus were investigated in vitro and in vivo. The specific IgY effectively inhibited the growth of V. parahaemolyticus in liquid medium rather than Escherichia coli and Staphylococcus aureus. Specific IgY antibodies were incorporated into extruded food pellets and fed to bacteria-challenged white pacific shrimp to observe the anti-bacterial effect in vivo. The bacterial loads in muscles of V. parahaemolyticus infected shrimp fed with specific IgY-included diets were significantly fewer than those fed with non-specific IgY-included diets. The superoxide dismutase activities in muscles of infected shrimp fed with specific IgY-included diets were significantly higher than the control group.

CONCLUSION

The results suggested that the specific IgY effectively inhibited the growth of V. parahaemolyticus and introduced passive immunity to shrimp. © 2018 Society of Chemical Industry.

The combined effects of lactoperoxidase system and whey protein coating on microbial, chemical, textural, and sensory quality of shrimp (Penaeus merguiensis) during cold storage (4 ± 1°C)

Growth and reproduction of gram-negative bacteria has a pivotal role in spoilage of seafood products. In order to identify the effect of lactoperoxidase system (LPOS), an antimicrobial activity was added to whey protein solution at the levels of 0 (control group), 1.25%, 2.5%, 5%, and 7.5%. Then, the shrimp samples were coated with immersion method and stored in the refrigerator for 16 days. In this period, the microbial tests of psychrotrophic bacteria, mesophilic bacteria, Pseudomonas fluorescens, Pseudomonas spp., and Shewanella putrefaciens, chemical tests of total volatile basic nitrogen, thiobarbituric acid, and pH, and sensory evaluation were carried out on the days of 0, 4, 8, 12, and 16. Adding LPOS in the coating resulted in a decrease in the total specific spoilage organisms and TVB-N. There was no significant effect for the TBA test. The levels of LPOS showed a positive correlation with the acceptable measurement in the sensory evaluation.

Characteristics of Two Lysis-Related Proteins from a Shewanella putrefaciens Phage with High Lytic Activity and Wide Spectrum

Although Shewanella putrefaciens is the specific spoilage organism in most seafood, only seven Shewanella phages have been sequenced and their endolysins have not been reported until now. In this study, we cloned and expressed two lysis-related proteins (Spp64 and Spp62) encoded by phage Spp001, the first sequenced S. putrefaciens phage. Both recombinant proteins showed strong lytic capability toward chilled S. putrefaciens Sp225 and presented a wider activity spectrum compared with bacteriophage Spp001. The enzymatic activity of crude Spp64, Spp62^ΔTD, and Spp62^ΔTD-GST can cause decreases of 0.691, 0.674, and 0.685, respectively, as tested through the turbidity reduction assay. Furthermore, purified enzyme Spp64 at concentrations of 537.5 and 4.20 μg/mL was enough to decrease the optical density of chilled S. putrefaciens by 0.881 and 0.492, respectively, within 15 min. The recombinant Spp64 has a peptidase catalytic domain and exhibits high temperature resistance. Moreover, Spp64 displayed superior enzymatic activity in a range of pH values that matches environmental conditions (pH between 5.0 and 10.0), which demonstrates that its application in seafood is feasible. The present work is to our knowledge the first report on lysis-related enzymes encoded in the Shewanella phage. Both proteins presented extraordinary potential to control S. putrefaciens; we hope that these proteins can be developed as novel antibacterial agents in further research.

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% N2, 10% O2) 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.

Chitosan coating incorporated with the lactoperoxidase system: an active edible coating for fish preservation

BACKGROUND

As a result of consumers' concerns about chemicals there is a particular interest in the food industry to use natural bio-preservatives such as antimicrobial enzymes for antimicrobial packaging. Based on the antimicrobial activity of the lactoperoxidase system (LPOS), the present study evaluated the coating effect of LPOS incorporated into chitosan solution (CH) on the quality and shelf life extension of rainbow trout during refrigerated storage (4 ± 1 °C), for a period of 16 days.

RESULTS

The results indicated that samples of the CH+LPOS group had significantly lower numbers of Shewanella putrefaciens, Pseudomonas fluorescens, and psychrotrophic and mesophilic bacteria than did the CH and control group during the entire storage period. Total volatile basic nitrogen (TVB-N) levels for the CH+LPOS samples (22.07 mg 100 g(-1)) did not exceed the limit of consumption (30-35 mg N 100 g(-1)), while the CH (31.03 mg 100 g(-1) ) and control groups (37.78 mg 100 g(-1) ) reached this level at days 12 and 16, respectively. Thiobarbituric acid values of the CH and CH+LPOS samples, ranged between 0.49 and 0.51 on day 0 and 4.59-4.66 mg kg(-1) on day 16, were significantly lower (P < 0.05) than the corresponding values of the control samples (0.47 on day 0 to 4.78 mg kg(-1) on day 16 of storage) during the chilled storage period.

CONCLUSION

The coating treatments (CH and CH+LPOS) extended the shelf life of trout fillets by at least 4 days as compared to the control samples, so that they showed moderate to high acceptability in all investigated sensory attributes even on the 16th day of storage.

Effects of Fab' fragments of specific egg yolk antibody (IgY-Fab') against Shewanella putrefaciens on the preservation of refrigerated turbot

BACKGROUND

In our previous studies the specific egg yolk antibody (IgY) against Shewanella putrefaciens (one of the specific spoilage organisms for marine products during aerobic chilling storage) demonstrated significant activity to prolong the shelf life of refrigerated fish. The exploitation of the antigen-binding fragment plus the hinge region (IgY-Fab') is now considered a promising method for improving the efficiency of such natural antimicrobial agents.

RESULTS

The antimicrobial activity of IgY-Fab' against S. putrefaciens was investigated using refrigerated turbot as samples. By microbial, chemical and sensory tests, it was shown to be able to effectively inhibit bacterial growth and prolong the shelf life of samples, with an efficiency evaluated significantly higher than that of whole IgY with the same molarity. The interaction between IgY agents and S. putrefaciens cells was also investigated, and the IgY-Fab' showed a much greater ability to damage cell membranes than the whole IgY.

CONCLUSION

Compared to whole IgY with the same molarity, IgY-Fab' demonstrated higher and more durable antimicrobial efficiency. Such a result was assumed to be closely related to its structural properties (such as the much lower molecular weight), which may enhance its ability to influence physiological activities of antigen bacteria, especially the property or/and structure of cell membranes.

Passive protective effect of chicken egg yolk immunoglobulins against experimental Vibrio anguillarum infection in ayu (Plecoglossus altivelis)

Oral administration of chicken egg yolk immunoglobulins (IgY) has attracted much attention as a means for controlling infectious diseases caused by microorganisms. This study evaluated the protective effect of IgY against Vibrio anguillarum infection in ayu, Plecoglossus altivelis. IgY was isolated from egg yolks laid by hens initially immunized with formalin-inactivated V. anguillarum. Lower mortality of ayu was observed in groups treated with anti-V. anguillarum IgY (aVIgY), compared with those treated with saline or with nonspecific IgY (nspIgY). All fish in saline-treated groups died within seven days after bacterial inoculation. The bacterial load in blood, liver, and spleen was significantly lower in fish treated with aVIgY than in fish treated with nspIgY. aVIgY treatment significantly reduced tumor necrosis factor-α (PaTNF-α), interleukin-1β (PaIL-1β), transforming growth factor-β (PaTGF-β), and leukocyte cell-derived chemotaxin-2 (PaLECT2) transcript levels in the head kidney, spleen, and liver of ayu challenged by V. anguillarum, compared with nspIgY treatment. The phagocytic activity of macrophages for V. anguillarum in the presence of specific IgY was significantly higher than that seen for nonspecific IgY. These results suggest that passive immunization by oral intubation with pathogen-specific IgY may provide a valuable treatment for V. anguillarum infection in ayu.