Enzymatic hydrolysis of ovalbumin and the functional properties of the hydrolysates.

Abeyrathne, E D N S,Lee, H Y,Jo, C,Nam, K C,Ahn, D U Poultry Science Association, etc 2014 Poultry science Vol.93 No.10

<P>Ovalbumin is the predominant protein in egg white and is widely used in cell culture. However, it also can be used to produce peptides with various functional properties. The objectives of this study were to hydrolyze ovalbumin using various enzyme, incubation time, and temperature combinations, and to compare the functional properties of the hydrolysates. Ovalbumin (20 mg/mL) was hydrolyzed with 1% of pepsin, trypsin, α-chymotrypsin, papain, and alcalase, singly or in combination at 37C, and then the enzymes were inactivated at 100C for 15 min. Hydrolyzing ovalbumin with pepsin (OAPe), pepsin + papain (OAPePa), pepsin + alcalase (OAPeAl), alcalase + trypsin (OAAlTr), and α-chymotrypsin (OACh) was also effective in producing peptides from ovalbumin, and the peptides produced had strong iron- and copper-binding capacities and antioxidant capability. However, the best treatment of all was the OAAlTr treatment, which showed the highest iron-chelating and antioxidant activities among the enzyme treatments (P < 0.05). Electrospray-ionization mass spectrometry (MS/MS) analysis identified numerous peptides (<5 kDa) from the OAPe, OAPeAl, OACh, OAAlTr, and OAPePa hydrolysates of ovalbumin, but the number and size of peptides varied widely depending on the treatments. The enzymatic hydrolysis significantly increased the functionality of ovalbumin, and the improvement depended upon the composition of peptides produced rather than the number of the peptides produced.</P>

Sequential Separation of Lysozyme and Ovalbumin from Chicken Egg White

Abeyrathne, Nalaka Sandun,Lee, Hyun Yong,Ahn, Dong Uk Korean Society for Food Science of Animal Resource 2013 한국축산식품학회지 Vol.33 No.4

Lysozyme was trapped from $2{\times}$ diluted egg white using Amberlite FPC 3500 ion exchange resin (1 g/10mL of egg white). The lysozyme bound to the resin was recovered using 0.1 N glycine-NaOH buffers, pH 9.0, containing 0.5 M NaCl. After separating lysozyme, the pH of the egg white solution was adjusted to 4.75 and centrifuged to remove interfering proteins. The supernatant was collected, added with 2.5% citric acid and 5.0% ammonium sulfate combination to precipitate egg white proteins, except for ovalbumin. After centrifugation, both supernatant (S1) and precipitant were collected. The precipitant was dissolved with 4 volumes of distilled water, and then 2.0% ammonium sulfate and 1.5% citric acid combinations added, stirred overnight in a cold room, and centrifuged. The resulting supernatant (S2) was pooled with the first supernatant (S1), desalted using an ultrafiltration unit, heat-treated at $70^{\circ}C$ for 15 min, and then centrifuged. The supernatant was collected as an ovalbumin fraction and lyophilized. The separated proteins were confirmed using Western blotting. The yield of lysozyme and ovalbumin was > 88.9% and > 97.7%, respectively, and the purity of lysozyme and ovalbumin was > 97% and 87%, respectively. The results indicated that the protocol was simple, and separated lysozyme and ovalbumin effectively.

Separation of ovotransferrin from chicken egg white without using organic solvents

Abeyrathne, E. D. N. S.,Lee, H. Y.,Ham, J. S.,Ahn, D. U. Poultry Science Association 2013 Poultry science Vol.92 No.4

<P>Ovotransferrin is one of the major egg white proteins that have antimicrobial activity as well as iron binding capability. The objective of this study was to develop a simple and easy method to separate ovotransferrin without using organic solvents. Egg white was separated from yolk, added in a 1:1 ratio to distilled water (DW), and then homogenized. The ovomucin in the diluted egg white was removed by centrifugation, adjusting the pH to 4.5 to 5.0. The resulting supernatant was added to different ratios of ammonium sulfate and citric acid, and then centrifuged after holding overnight at 4°C. The precipitant, which contains ovotransferrin, was dissolved in DW, and ovotransferrin was precipitated using different ratios of ammonium sulfate and citric acid. The precipitant collected after centrifugation was dissolved with DW and subjected to ultrafiltration to remove salts and concentrate the solution. The purity of the ovotransferrin was determined using SDS-PAGE, the protein identified using Western blot, and the estimated yield calculated by weighing the ovotransferrin after freeze drying. Over 85% purity and over 83% yield were obtained from the combinations of 5.0% (wt/vol) ammonium sulfate and 2.5% (wt/vol) citric acid followed by 2.0% (wt/vol) ammonium sulfate and 1.5% (wt/vol) citric acid. Activity of the ovotransferrin showed similar activity with previously separated ovotransferrin. However, this method is simpler and more cost effective than the previous method. The isolated ovotransferrin can be used as is or after modifications for various applications such as antimicrobial treatments, anticancer treatments, and iron-supplementing agents for humans.</P>

Separation of ovotransferrin and ovomucoid from chicken egg white

Abeyrathne, E.D.N.S.,Lee, H.Y.,Ahn, D.U. POULTRY SCIENCE ASSOCIATION 2014 Poultry science Vol.93 No.4

Sequential separation of lysozyme, ovomucin, ovotransferrin, and ovalbumin from egg white

Abeyrathne, E.D.N.S.,Lee, H.Y.,Ahn, D.U. POULTRY SCIENCE ASSOCIATION 2014 Poultry science Vol.93 No.4

Egg yolk lipids: separation, characterization, and utilization

Edirisingha Dewage Nalaka Sandun Abeyrathne,남기창,Xi Huang,AhnDongUk 한국식품과학회 2022 Food Science and Biotechnology Vol.31 No.10

Egg yolk contains very high levels of lipids, which comprise 33% of whole egg yolk. Although triglyceride is the main lipid, egg yolk is the richest source of phospholipids and cholesterol in nature. The egg yolk phospholipids have a unique composition with high levels of phosphatidylcholine followed by phosphatidylethanolamine, sphingomyelin, plasmalogen, and phosphatidylinositol. All the egg yolk lipids are embedded inside the HDL and LDL micelles or granular particles. Egg yolk lipids can be easily extracted using solvents or supercritical extraction methods but their commercial applications of egg yolk lipids are limited. Egg yolk lipids have excellent potential as a food ingredient or cosmeceutical, pharmaceutical, and nutraceutical agents because they have excellent functional and biological characteristics. This review summarizes the current knowledge on egg yolk lipids' extraction methods and functions and discusses their current and future use, which will be important to increase the use and value of the egg.

Combined Effect of Post-Slaughtering Storage and Single Beam Irradiation on Physiochemical Quality of Pork Leg Meat Stored at Different Temperatures

Edirisinghe Dewage Nalaka Sandun Abeyrathne,Ki-Chang Nam 경상대학교 농업생명과학연구원 2021 농업생명과학연구 Vol.55 No.6

Post-slaughtering storage of pork meat is important to improve the flavor and texture profile. Although irradiation of meat improves the keeping qualities of red meat, less work was done on the effect of quality in irradiated pork leg meat during post-slaughtering storage. Therefore, this study was done to compare low dosages of single beam irradiation treated pork leg meat on eating quality parameters over the nontreated meat stored at different storage temperatures. Freshly slaughter pig carcasses were brought to the irradiation unit for treatment. Pork leg meat was treated at 2 kGy with single beam. Treated (2 kGy) and non-treated pork leg meat were kept in three different temperatures as 2, 10 and 25°C for 1, 3 and 5 days and analyzed for cooking loss, shear force, color and nitrogenous flavor compounds. Cooking loss in day 5 in irradiated pork leg (30.29) was significantly lower than the control (33.27) (p<0.05). Shear force of treated (1.93) and non-treated (1.29) pork leg meat after day 5 had significant difference (p<0.05). “L*” and “b*” values of pork leg meat had significant difference at day 5 compared non treated leg meat (p<0.05) whereas the “a*” value was increased with storage time and temperature. Hypoxanthine level was significantly lower in pork leg meat at day 5 in treated (16.07) and non-treated (24.59) meats at 25°C (p<0.05) whereas the changes in AMP, IMP and Inosine was not significantly difference (p>0.05). As conclusion, post-slaughtering storage and irradiation with single beam of 2 kGy could ensure the meat quality of leg pork at even higher storage temperatures, with cooking loss, tenderness, flavor and the color which will be benefited in the processing industry.

Impact of Irradiation in Meat Quality on Pork Sausage Products Using Hot and Cold Carcasses, Stored at Different Aging Temperatures

Edirisinghe Dewage Nalaka Sandun Abeyrathne,남기창 경상국립대학교 농업생명과학연구원 2022 농업생명과학연구 Vol.56 No.1

This study examined the effects of hot deboning and the irradiation of raw pork on the physicochemical properties of pork sausages. Pigs were deboned with a carcass (loin surfaces) temperature of 5℃ (cold) or 15℃ (hot). Each deboned raw pork loins were then irradiated at 0 kGy or 4 kGy. Emulsion-type sausages were prepared from each treated meat with other ingredients including fat, ice, salt, phosphate, and seasoning powder. Then sausage products were analyzed for their physiochemical properties and microbial spoilage up to 10 days. Emulsion stability of sausage products with hot deboning was better than the cold carcass up to three days. Sausage products with irradiated hot carcasses showed less cooking loss than from non-irradiated carcasses on day 10. Hardness, gumminess, and chewiness of the sausages decreased significantly with increasing storage time for all sausage products (p<0.05), but the sausage products with irradiated hot carcasses showed a smaller reduction compared with non-irradiated. Lipid oxidation was not significantly different in the sausage products with hot or cold deboning (p>0.05), but the sausage products from non-irradiated meats showed changes from 0.43 to 1.59 (MDA mg/kg of meat) in 10 days (p<0.5). Total plate count and E. coli count were significantly lower in the sausage products from irradiated meat (p<0.05). Finally, irradiating hot deboned meat at 4 kGy can be an excellent alternative for producing raw meat for sausages with promising microbiological and physicochemical properties.

Poster Session : PS 0403 ; Infectious Disease ; Early Identifi cation of Plasma Leakage in Pregnant Dengue Patients

( Priyankara Jayawardena ),( Gaveshika Abeyrathne ),( Damayanthi Idampitiya ),( Deshapriya Ananda Wijewickrama ) 대한내과학회 2014 대한내과학회 추계학술대회 Vol.2014 No.1

Background: Dengue Haemorrhagic Fever (DHF) is the commonest complication in Dengue. Early identifi cation of plasma leakage in DHF is very important to prevent patients from going into shock. Rising haematocrit (HCT) is the commonest parameter used to detect DHF. However, no data is available for dengue in pregnancy. Methods: Retrospective observational study was conducted on all pregnant Dengue patients admitted to two hospitals in Colombo during 2013 to identify parameters useful in diagnosing DHF. Dengue infection was confi rmed by positive serology; DHF by Ultra Sound Scan (USS). Results: 58 qualifi ed for the study. Mean age was 28.45(SD: 5.573) yrs. 32(55.2%) had Dengue fever (DF) while 26(44.8%) had DHF. All had fever. 86.2% had myalgia. Hepatic tenderness, persistent vomiting and postural dizziness were commoner with DHF (81.8%, 100% & 70% respectively). Temperature, pulse rate and urine output had no signifi cant differences between DF and DHF. The mean lowest platelet count in DF was 90.94 while in DHF was 37.81 (p<0.000). Both AST and ALT levels were higher in DHF. PT/INR (6.8%) and APTT (8.6%) were elevated in both DF & DHF. Of the 32 DF patients, 19 (59%) had HCT rise of <10%, and other 13(40.6%) had HCT rises between 11% to 19%. Of the 26 DHF patients, 3 (11.5%) had HCT rise of <10%, 12 (46.2%) had HCT rises between 11% to 19% while 11 had HCT rise of >20%. Only one patient went into shock. All patients recovered fully. Conclusions: Lower platelet count and higher ASOT & ALT were in favour of DHF. HCT changes are helpful to diagnose DHF only when it is >20%. However, lesser changes don`t exclude the possibility of DHF. Hence, we recommend that USS should be used routinely in all pregnant patients to diagnose DHF.

Sequential separation of immunoglobulin Y and phosvitin from chicken egg yolk without using organic solvents.

Lee, Hyun Yong,Abeyrathne, E D N S,Choi, Inwook,Suh, Joo Won,Ahn, Dong Uk Poultry Science Association, etc 2014 Poultry science Vol.93 No.10

<P>A study was conducted to develop a simple sequential separation protocol to separate phosvitin and IgY from egg yolk without using organic solvents. Egg yolk was diluted with 2 volumes of distilled water (DW), homogenized, and centrifuged. The precipitant was collected and homogenized with 4 volumes of 10% NaCl (wt/vol) in 0.05 N NaOH solution to extract phosvitin. The pH of the homogenate was adjusted to 4.0 and the precipitate was removed by centrifugation. The supernatant was collected and then heat-treated at 70C for 30 min and centrifuged to remove impurities. The supernatant containing phosvitin was collected, had salts removed, and was concentrated and then freeze-dried. The supernatant from the centrifugation of diluted egg yolk was diluted again with 3 volumes of DW, and the precipitate was removed by centrifugation. The resulting supernatant was concentrated using ultrafiltration and then IgY was precipitated using 20% saturated (NH4)2SO4+ 15% NaCl (wt/vol). The precipitant was collected after centrifugation at 3,400 g for 30 min at 4C and dissolved with DW, had salts removed, and then was freeze-dried. The purity of separated phosvitin and IgY was checked using SDS-PAGE and the proteins were verified using Western blotting. The purity of phosvitin and IgY was 97.2 and 98.7%, and the yield was 98.7 and 80.9%, respectively. The ELISA results indicated that the activities of separated IgY and phosvitin were 96.3 and 98.3%, respectively. This study proved that both phosvitin and IgY can be separated in sequence from egg yolk without using an organic solvent. Also, the method is very simple and has a high potential for scale-up processing.</P>