• Korean Journal of Poultry Science
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• v.49 no.4
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• pp.221-228
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• 2022

Major egg white proteins and their hydrolysates serve as functional food ingredients that have certain metal-chelating properties. Employing egg white proteins and their hydrolysates to scavenge dietary oxalates is anticipated to have beneficial effect in the prevention of kidney stones. The objective of this study was to determine the biogenic oxalate-chelating activity of ovalbumin, ovomucin, and ovotransferrin and their hydrolysates. To prepare oxalate extracts, 30 mL of 0.25 N HCl was added to separately to 0.5 g of dried spinach and starfruit powders followed by boiling for 15 min, and after cooling, the addition of a further 20 mL of 0.25 N HCl. Having prepared these extracts, ovalbumin, ovomucin, and ovotransferrin and their hydrolysates were separately mixed with oxalate extracts and incubated at 3℃ for 24 h. Following centrifugation, supernatants were analyzed by HPLC using a reverse-phase C18 column coupled with a diode array detector. We found that all assessed proteins and their hydrolysates showed biogenic oxalate-chelating activity against the oxalates of spinach. In contrast, however, only ovalbumin, ovalbumin-hydrolysate, and ovomucin showed chelating activity (57.10%±8.84%, 85.44%±5.30%, 73.20%±4.13%, respectively) against the oxalates of starfruit (P<0.05). Overall, hydrolyzed ovalbumin was identified as the most effective chelator of the oxalates both spinach and starfruit. In this study, we thus established that the assessed egg white proteins and their hydrolysates have oxalate-chelating activity in vitro, thereby indicating that these compounds have potential utility as nutraceuticals for the chelation of dietary oxalate. However, further research will be necessary to verify their oxalate-chelating activities against different fruits and vegetables and under specific in vivo conditions and against purified oxalate.

• Korean Chemical Engineering Research
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• v.50 no.4
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• pp.713-717
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• 2012

Approximately forty proteins in egg white have been widely studied for their functional properties. To develop a procedure of separation for pure and non-altered proteins from egg white, purification study was conducted to isolate lysozyme, ovotransferrin, and ovalbumin. Ion exchange cartridge can selectively separate proteins from egg white, and reversed-phase HPLC (RP-HPLC) could identify separated proteins. Proteins in egg white were purified by HI trap ion exchange cartridge SP and Q with buffers pH 8.0 and 5.2. C18 column (Phenomenex, USA) was used for RP-HPLC analysis and isocratic mobile phase was used with acetonitrile (ACN)/distilled water (DW)/trifluoroacetic acid (TFA) in the ratio of 50/50/0.1. Comparing the retention times of standards in RP-HPLC experiments showed that ovotransferrin, ovalbumin, and lysozyme in egg white were eluted successively in the RP-HPLC column after the pretreatment in SP and Q ion exchange cartridges.

• Journal of the Korean Society of Food Science and Nutrition
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• v.20 no.4
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• pp.363-368
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• 1991

To fortificate protein to soybean curd, 0, 20, 40, 60 and 80% (v/v) of egg white (EW) were added to soybean milk for the soybean curd preparation, respectively. Moisture, $Ca^{2+}$, crude lipid and ash content of the curd were decreased as EW increased whereas protein content, weight and volume, $Mg^{2+},\;K^{+},\;and\;Na^{+}$ incresed, and hardness also increased. In addition, coagulating temperature and hardness were lowered as EW increased. Color and taste panel score were not significantly different (p<0.01), however, texture and flavor score were lowered over 60% (v/v) EW addition. By adding EW (20, 40, 60 and 80%), sulfur containing amino acids were enriched 0.63, 1.20, 1.76 and 2.36 times, respectively compared to the control(0%).

• Membrane Journal
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• v.26 no.4
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• pp.266-272
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• 2016

The separation and purification of lysozyme enzyme from chicken egg white (CEW) solution was studied using the dead-end filtration. The optimum operation conditions of the dead-end filtration reveal that the maximum value of permselectivity of lysozyme to the other proteins of ovalbumin and conalbumin in the CEW solution was tested with change of molecular weight cut-off (MWCO) of ultrafitration membrane and pH of the CEW solution. The optimum operation conditions for the efficient permeable separation of lysozyme from the CEW solution are that the membrane MWCO is 30 kD and the pH of CEW solution is 11. At this optimum operation conditions, the maximum value of permselectivity of lysozyme to total proteins in CEW solution is about 83.

• Korean Journal of Food Science and Technology
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• v.31 no.2
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• pp.458-464
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• 1999

The value of lysozyme as a natural food preservative is continuously increased due to its unique antimicrobial activity. To determine the optimum separation concentration among the various hen egg white protein (HEWP) concentrations (0.25, 0.5, 1.0, w/v), protein concentrations, lysozyme concentrations, specific activities (SA), and purification factors of prefiltered solution (PFS) and PM30 permeate solution (PMS) were compared. The purity of lysozyme separated at each step was analyzed and confirmed by gel permeation chromatography and electrophoresis. The fouling deposits on membrane were observed by SEM. The non-enzymatic proteins were removed over 99% by ultrafiltration (UF). The increased feed concentration did not contribute to the increase of SA. SA of PMS was 18 to 31 times higher than that of PFS. The optimum feed concentration was decided as 0.25% based on SA and purification factor. The non-enzymatic region of gel chromatogram was proved to be ovalbumin. The thickness of deposit on the UF membrane was approximately $0.9{\mu}m$ and removed by cleaning with 0.1 N NaOH. Therefore, UF using PM30 membrane was very effective to separate the antimicrobial lysozyme from various HEWPs.

• Proceedings of the Korean Society for Food Science of Animal Resources Conference
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• 2004.05a
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• pp.376-379
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• 2004

본 연구는 알레르기 저감화 식품을 개발하기 위한 실용화 방법의 일환으로 실시되었다. 계란으로부터 난백을 분리하여 감마선을 10 및 20 kGy로 조사한 후 케이크를 만들어 알러지원성을 측정하였다. 감마선 조사된 난백으로 만든 케이크에서 추출된 단백질은 전기영동을 통해 확인하였으며 각 시료에 대한 알러지원성은 계란 알레르기가 있는 환자의 혈청을 사용하여 측정한 결과, 난백에 대한 조사 선량이 증가할수록 알러지원성이 감소하는 것을 확인할 수 있었다. 이상의 결과로 볼 때, 감마선 조사된 난백으로 만든 케이크는 대조구에 비해 알러지원성을 감소시킬 수 있었으며 방사선 조사를 통해 알레르기가 저감화된 식품을 개발할 수 있을 것으로 보인다.

• Applied Biological Chemistry
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• v.43 no.4
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• pp.260-265
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• 2000

To determine the quality change of the irradiated eggs during storage, fresh shell eggs were irradiated using $^{60}Co$ at 0, 1, 5, 10, 30 kGy and stored for 30 days. The york index, color, pH, viscosity, egg weight, and SDS-PAGE profile of the irradiated eggs were examined. During storage, york index values of the irradiated eggs and the control were decreased and the increase of dose decreased yolk index. However, the yolk index values were increased temporarily at 10 kGy and 30 kGy. The yolk color had a bright yellow with increases in dose level and there was no significant change during storage. The albumen viscosities were decreased with increases in dosage and were decreased during storage. Also, the albumen pH values of the irradiated eggs were higher than that of the control and were increased during storage. The weight losses of eggs were increased during storage and there were no significant changes by dose level. SDS-PAGE profile of the egg white proteins of the shell eggs showed the change in molecular weight distribution and had aggregation pattern as well as degradation. CD and fluorescence spectroscopy study showed changes in the secondary and tertiary structure of egg white proteins by ${\gamma}-irradiation$. Therefore, this study clearly indicates that irradiation dose of eggs should be appropriate to prevent the loss of egg qualities.

• Korean Journal of Poultry Science
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• v.16 no.1
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• pp.23-28
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• 1989

This study was undertaken to find out the effect of eeg albumen concentration and addition of sugars on the functional properties of egg albumen before and after heat treatment at $60^{\circ}C$ for 5 minutes. The turbidity was decreased until 8.3% protein concentration but increased as diluted and decreased again below 3.32% protein concentration before and after the heat treatment. The foaming power was peak at 8.3% protein concentration but decreased as diluted before and after the heat treatment. The foam stability was decreased as diluted before and after the heat treatment. The turbidity was not changed by addition of sucrose before the heat treatment and decreased after the heat treatment. The foaming power was decreased by addition of over 5% sucrose before the heat treatment and decreased by addition of over 2.5% sucrose after the heat treatment . The foam stability was increased by addition of over 5% sucrose before the heat treatment and increased by addition of sucrose after the heat treatment. The turbidity was increased by addition of glucose before the heat treatment and not changed after the heat treatment. The foaming power was decreased by the addition of glucose before the heat treatment and decreased by the addition of over 5% glucose after the heat treatment. The foam stability was decreased by the addition of glucose before and after the heat treatment.

• Korean Journal of Poultry Science
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• v.17 no.3
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• pp.211-216
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• 1990

This study was undertaken to find out the effect of egg albumen concentration and addition of sugars on heat stability of egg albumen gel after heat treatment at $95^{\circ}C$ for 30 minutes or at $120^{\circ}C$ for 30 minutes. The hardness of albumen gel was decreased rapidly and the lightness and yellowness was decreased slowly as egg albumen was diluted regardless of heating condition. The cohesiveness was increased as the protein concentration was decreased at below 8.3%. The hardness of albumen gel was decreased by the addition of over 2.5% sucrose, and the cohesiveness was decreased slightly with the addition of sucrose. The addition of glucose improved the cohesiveness and decreased lightness remarkably after heat treatment at 120% for 30 minutes.

• Proceedings of the Korean Society of Fisheries Technology Conference
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• 2001.05a
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• pp.154-155
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• 2001

난백과 혈장, 대두단백질은 겔화식품의 겔강화와 단백질 보강의 목적으로 다양하게 사용되고 있으며, 이 때 첨가단백질의 겔화 특성은 가장 중요한 피능적 특성중 하나이다. 이러한 겔화에는 단백질의 종류, 가열온도와 시간, 염의 유무, pH등의 환경이 복합적으로 작용하여, 소수성 상호작용, 공유결합, 이온결합, S-S결합 및 수화력 등이 겔을 형성한다. 단백질의 겔화에 미치는 변수에 대한 많은 연구가 이루어졌지만 단백질의 겔화 특성에 있어 가장 많은 구성비율을 차지하는 수분과 수화력에 관한 연구는 미미한 실정이다. (중략)