• Food Science and Preservation
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• v.31 no.3
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• pp.444-451
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• 2024

This study aimed to investigate the characteristics of protein hydrolysates derived from defatted egg yolk using various proteolytic enzymes and compare the antioxidant activity of the resulting hydrolysates. The defatted egg yolk powder was subjected to enzymatic hydrolysis using four different proteases (alcalase, bromelain, flavourzyme and neutrase), and the resulting hydrolysates were evaluated for their antioxidant properties. Through analysis of available amino group contents and sodium dodecyl sulfate-polyacrylamide gel electrophoresis, it was observed that the defatted egg yolk powder treated with alcalase, flavourzyme, and neutrase for 12 h exhibited a high degree of hydrolysis value. Based on the RC₅₀ values obtained from two different antioxidant analyses, all hydrolysates showed comparable antioxidant activity, except for the alcalase hydrolysate, which demonstrated notably higher scavenging activity against hydrogen peroxide than the other hydrolysates. These findings suggest the potential of protein hydrolysates from defatted egg yolk, a by-product of lecithin extraction, as natural antioxidants.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.46 no.4
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• pp.351-358
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• 2013

A protease inhibitor from fish eggs was fractionated using chromatographic methods. The fractionation efficiency was evaluated in terms of specific inhibitory activity (SIA, U/mg), purity (fold), total inhibitory activity (TIA, U), and recovery (%). The protease inhibitor (PI) from egg extracts of skipjack tuna (ST Katsuwonus pelamis), yellowfin tuna (YT Thunnus albacares) and Alaska pollock (AP Theragra chalcogramma) was fractionated using Sephadex G-50 gel filtration and DEAE-Sepharose CL-6B anion exchange chromatography based on protein size exclusion and net charge, respectively. Fractions exhibiting strong inhibitory activity were contained in the 30-50 kDa fraction on gel filtration and in the range of 0.4-0.7 M NaCl gradient fraction on anion exchange chromatography. The respective TIA and percent recovery of the fraction obtained with gel filtration toward trypsin and $N{\alpha}$-benzoyl-L-arginine-p-nitroanilide (BAPNA) were 2,758.7 U and 29.6% for ST, 1,005.5 U and 25.6% for YT, and 1,267.5 U and 26.0% for AP. Gel filtration chromatography was more effective at fractionating PI than using ion exchange chromatography. These results suggest that fish eggs act as serine protease inhibitors and might be useful for protease inhibition in foodstuffs.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.44 no.1
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• pp.37-44
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• 2011

We investigated the optimum formulation to improve the gelling ability of squid, Dosidicus gigas, surimi. The solubility of minced squid muscle was highest at pH 10.7, and lowest at pH 5.0. The yields of conventional surimi and protein recovery after alkaline pH-shift processing were $68.1{\pm}2.4%$ and $65.3{\pm}2.6%$, respectively, whereas the protein recovery with acidic pH-shift processing was only $21.2{\pm}1.6%$. The addition of 5% starch decreased the breaking force regardless of the kind of starch, while the mixture of corn, potato, and wheat starch (total 15%) increased the breaking force by up to 1.9 fold. The addition of 5% egg white, 5% porcine plasma protein, 0.3% $CaCl_2$, and 0.3% Polymix GA significantly increased the breakingforce (P<0.05). None of the ingredients examined in this study significantly affected the deformation value (P<0.05). The optimum concentrations of egg white and $CaCl_2$ to obtain a breaking force of 55 g and a whiteness of 70 were 2.69% and 0.22%, respectively.

• Macromolecular Research
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• v.13 no.1
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• pp.39-44
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• 2005

Ion-exchange polymeric stationary phases presenting amino acid and amino groups were prepared by the surface grafting of glycidyl methacrylate onto a silica gel surface and subsequent amination. Three kinds of amino acids-L-arginine (Arg), D-lysine (Lys), and D-histine (His)-were used in this study. An ion-exchange polymeric stationary phase presenting ethylene diamine (EDA) was also prepared by surface graft polymerization. Separation of the model proteins bovine serum albumin (BSA), chick egg albumin (CEA), and hemoglobin (Hb) was performed using the amino acid- and amine-derived columns. In separating the CEA/BSA mixture, the resolution time of BSA was longer than that of CEA when using the EDA column, whereas the resolution time of BSA was shorter than that of CEA when using the Arg, Lys, and His columns. In the separation of the Hb/BSA mixture, the resolution time of BSA was longer than that of Hb in the EDA column, whereas the resolution time of BSA was shorter than that of Hb in the amino acid columns (D-Lys, L-Arg, and D-His).

• Korean Journal of Veterinary Service
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• v.23 no.4
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• pp.349-360
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• 2000

An epidemiological survey was conducted to investigate fowl typhoid outbreaks in Kyungnam province of Korea. The causative agent, salmonella gallinarum was isolated from 68 chicken samples of tentatively diagnosed fowl typhoid cases occurred during the period from January 1996 to September 1999. Comparative studies were also carried out to evaluate the diagnostic methods for detection of S gallinam The results obtained were as follows; 1. Of the 68 cases of tentatively diagnosed fowl typhoid, 56 (82%) cases were determined as fowl typhoid by biochemical test and pathological findings. The other 12 (18%) cases were determined as paratyphoid. 2. Fowl typhoid outbreaks occur continuously all seasons in the year, however the incidence was remarkably increased from May to September. 3. The frequency of incidence of fowl typhoid in terms of regional distribution was relatively high in egg-laying hens facilities, and the mode of transmission is likely to be either egg-to-egg or lateral transfer by wild birds or rats. 4. All of 18 isolates from 56 cases were identified as S gallinarum by biochemical and serological test. 5. Antimicrobial drug susceptibility test against 18 isolates showed that the isolates were highly susceptible to ASH, CZ, CF and GM (above 90%), whereas those strains were 100% resistant to EM, NA and PC. 6. S gallinarum rfbS gene was targeted to be amplified by PCR for comparative detection of S gallinarum in the experimentally infected chickens. The amplified 720bp DNA fragment, which is specific in D serogroup strains of S enterica subspecies was confirmed by agarose gel electrophoresis. 7. A comparison made between fecal culture and PCR-method revealed that later-method was relatively higher in detection rate than that of former method for S gallinarum. 8. Comparison of currently applied methods, rapid serum agglutination test (RST) and microplate agglutination test (MAT), with experimentally infected chickens were made to evaluate sensitivity of detection by neutralizing antibody titration. Both methods detected neutralizing antibodies from the challenged chickens of 5 day post infection. However, positive reactions were determined after 7 and 9 days post infection by MAT and RST, respectively.

• Food Science of Animal Resources
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• v.38 no.2
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• pp.291-301
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• 2018

To shorten the production cycle of Zaodan, this study first pickled Zaodan by a novel technology - vacuum decompression technology. Vacuum decompression technology could reduce the pickling time of Zaodan from 20 wk to about 9 wk. The protein content, moisture and pH of the Zaodan egg white gradually decreased with a concomitant increase in salt during the pickling process. The total sulfhydryl group (SH) group content of the egg white proteins was increased to $2.43{\times}10^{-3}mol/L$ after being pickled for 30 d, whereas the content of disulphide bonds (SS) was reduced to $23.35{\times}10^{-3}mol/L$. The surface hydrophobicity was lowest after pickling for 30 d. In addition, great changes occurred in the secondary structure of the egg white proteins after pickling for 20 d. The disappearance of ovomucin was noticeable based on sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis.

• KSBB Journal
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• v.18 no.2
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• pp.122-126
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• 2003

Multi-cycle chromatographic separation of Iysozyme from egg white was investigated. Multi-cycle chromatography was performed by repeated cycling(one cycle: resin equilibration, sample loading, washing, elution). Two types of cation exchange resins, Cellufine CM C-200 and Bio-rex 70, were used to determine the optimum condition for the separation of Iysozyme by multi-cycle chromatography. The resin was equilibrated in 20 mM Na-phosphate buffer(pH 7.0). Chromatograms of UV absorbance levels of every cycle were compared to confirm the eluting ability of Iysozyme in the two types of gel. Collected samples from eluting regions in every cycle were assayed by 15% SDS-PAGE.

• Microbiology and Biotechnology Letters
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• v.22 no.1
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• pp.73-79
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• 1994

The optimum cultural temperature and time for the pullulanase production by Bacillus cereus subsp. mycoides were 35$\circ $C and 48 hrs, respectively. The addition of egg albumin and casein to the basal medium increased the enzyme production. The enzyme was purified by ammonium sulfate fractionation and DEAE-cellulose column chromatography. specific activity of the purified enzyme was 82.37 U/mg protein and yield of theenzyume activity was 62.1%. The purified enzuyme showed a single band on ployacrylamide disc gel electrophoresis and its molecular weight was estimated to be 66.,000 by SDS-polyacrylamide disc gel electrophoresis. The isoelcular point for the purified enzyme was pH 5.0. The optimum temperature and pH were 50$\circ $C and pH 6.5, respectively. The purified enzyme was stable below 40$\circ $C and in the pH range of 6.5~10.0 The pullulanase activity was greatly inhited by Ag$^{+}$, Hg$^{2+}$ and EDTA, and its heat stability was increased by the addition of Ca$^{2+}$. The tydrolysis product with the enzyme on pullulan was maltotriose.

• Journal of Sericultural and Entomological Science
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• v.31 no.2
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• pp.72-81
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• 1989

Antheraea yamamai vitellin was purified from matured eggs by polyacryamide gel electrophoresis, also stage dependent appearance, immunological comparison and relative content of the protein were investigated. 1. Vitellogenin, the precursor of vitellin, was first detected in the larval hemolymph at the late spinning stage by polyacrylamide gel electrophoresis and immunoelectrophoresis. 2. The electrophoretic mobility of the vitellin was identical with that of Bombyx mori and of Bombyx mandarina. However, the specific antiserum against A. uamamai vitellin did not react with either that of Bombyx mori or Bombyx mandarina in immumo-diffusion test. 3. Relative content of A. yamamai vitellin to the total soluble egg protein was 46.0 percent and did not change till eight days after oviposition. But the content started to decline from ten days after oviposition and was negligible in the five or serventeen month old eggs.

• Parasites, Hosts and Diseases
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• v.52 no.1
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• pp.117-120
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• 2014

Several studies have reported that the citrus red mites Panonychus citri were an important allergen of citrus-cultivating farmers in Jeju Island. The aim of the present study was to purify and assess properties of a cysteine protease from the mites acting as a potentially pathogenic factor to citrus-cultivating farmers. A cysteine protease was purified using column chromatography of Mono Q anion exchanger and Superdex 200 HR gel filtration. It was estimated to be 46 kDa by gel filtration column chromatography and consisted of 2 polypeptides, at least. Cysteine protease inhibitors, such as trans poxy-succinyl-L-leucyl-amido (4-guanidino) butane (E-64) and iodoacetic acid (IAA) totally inhibited the enzyme activities, whereas serine or metalloprotease inhibitors did not affect the activities. In addition, the purified enzyme degraded human IgG, collagen, and fibronectin, but not egg albumin. From these results, the cysteine protease of the mites might be involved in the pathogenesis such as tissue destruction and penetration instead of nutrient digestion.