• 한국음향학회지
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• 제9권6호
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• pp.74-80
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• 1990

천연 단백질인 egg white의 gel화의 과정을 초음파 측정에 의하여 연구하였다. Egg white는 6 0℃ 이상의 어떤 온도에서 aging 측정을 하면 gel화의 진행에 따라 흡수는 증가, 음속은 감소하였다. Egg white의 gel 화는 60℃와 75℃에서 크게 진행하였고, egg white gel의 비가역성을 반영해서 음속과 흡수 모두 이력현상이 관측되었다.

• Preventive Nutrition and Food Science
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• 제20권3호
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• pp.183-189
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• 2015

In the present study, an optimum protease was selected to hydrolyze the egg white liquid protein for the antioxidant peptides. Alcalase treatment yielded the highest amount of ${\alpha}$-amino groups (15.27 mg/mL), while the control (no enzymatic hydrolysis) showed the lowest amount of ${\alpha}$-amino groups (1.53 mg/mL). Alcalase also gave the highest degree of hydrolysis (DH) value (43.2%) and was more efficient for egg white liquid hydrolysis than the other enzymes. The Alcalase hydrolysate had the highest radical-scavenging activity (82.5%) at a concentration of 5.0 mg/mL. The conditions for enzymatic hydrolysis of egg white liquid with Alcalase were selected as substrate : water ratio of 2:1. Five percent Alacalse treatment did not show significant (P>0.05) increases of DH and ${\alpha}$-amino nitrogen content after 24 hhydrolysis. Thirty two hour-hydrolysis with 5% Alcalase is sufficient to make antioxidative egg white liquid hydrolysate from egg white liquid. DPPH and ABTS radical-scavenging activities were significantly (P<0.05) higher after enzymatic digestion. These results suggest that active peptides released from egg-white protein are effective radical-scavengers. Thus, this approach may be useful for the preparation of potent antioxidant products.

• KSBB Journal
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• 제22권2호
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• pp.119-122
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• 2007

RP-HPLC에서 주요 변수인 이동상의 조성과 컬럼의 종류를 변화시켜 난백 단백질을 실험하였다. C4, C8 C18 컬럼을 비교 실험하여 C18 컬럼에서 가장 많은 피크를 보여 C18 컬럼을 선택하였다. 등용매 용리에서 ACN : water의 조성이 50 : 50에서 가장 많은 피크를 보여 이 결과를 토대로 기울기 용리를 하여 실험하였다. 기울기 용리에서 얻어진 4가지 피크를 확인하기 위하여 단일성분인 lysozyme와 ovalbumin의 체류시간을 측정하여 확인하였고 논문을 통해 2가지 피크를 예측할 수 있었다.

• Asian-Australasian Journal of Animal Sciences
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• 제32권6호
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• pp.881-890
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• 2019

Objective: A study was conducted to develop non-dairy creamer analogs/mimics using egg white, egg yolk, soy protein and their combinations, and their nutrient content, shelf-life and flavor acceptability were compared. Methods: Spray dried egg white, egg yolk, and soy protein isolate were purchased from manufacturers and used for the formulae. Results: The protein contents of the non-dairy creamer analogs/mimics were about 8.5% as calculated. The amounts of oleic and linoleic acid content increased as the amount of yolk increased in the formula, but the increases of polyunsaturated fatty acids were <0.5% of total fat. Addition of egg yolk to the formula increased choline and lutein content in the products, but the amounts were <0.4 mg/g for choline and $4{\mu}g/g$ for lutein. The lutein in the products continued to decrease over the storage time, and only about 15% to 20% of the 0-month amounts were left after 3 months of storage. Although the thiobarbituric acid reactive substances values of the spray-dried non-dairy creamer analogs/mimics increased as storage time increased, the values were still low. Yellowness, darkness, and egg flavor/odor of the non-dairy creamer analogs/mimics increased as the amount of egg yolk in the formula increased. The overall acceptability of the non-dairy creamer analogs/mimics was closely related to the intensity of egg flavor/odor, but storage improved their overall acceptance because most of the off-odor volatiles disappeared during the storage. Water temperature was the most important parameter in dissolving spray-dried non-dairy creamer analogs/mimics, and $55^{\circ}C$ to $75^{\circ}C$ was the optimal water temperature conditions to dissolve them. Conclusion: Higher amounts of yolk and soy protein combinations in place of egg white reduced the cost of the products significantly and those products contained better and balanced nutrients than the commercial coffee creamers. However, off-flavor and solubility were two important issues in the products.

• Journal of Animal Science and Technology
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• 제51권6호
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• pp.521-526
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• 2009

Irradiation of egg white increased foaming ability significantly. To investigate the protein modification by irradiation responsible for the increase of foaming ability, 3 major egg white proteins were purchased and mixed (7.7 g/L ovalbumin, 1.8 g/L ovotransferrin, 0.5 g/L lysozyme) as a model system and irradiated at 0, 2.5, and 5 kGy. The different protein expressions were evaluated using 2-D electrophoresis and it was found that ovotransferrin was cleaved by irradiation and molecular weight and isoelectric point were changed. In addition, many uncharacterized proteins were found and it indicated that irradiation modified proteins randomly but mainly fragmentation was observed. Therefore, it can be concluded that protein fragmentation of 3 major egg white proteins responsible for foaming ability may be the main reason for the improvement of foaming ability.

• 한국조리학회지
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• 제24권2호
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• pp.103-111
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• 2018

The objectives of the present study were to examine the antioxidant activity of autofocusing fractions from egg white protein hydrolysates and obtain higher antioxidant peptide fraction, which could be applied to the food model system. Alkaline protease hydrolysate of egg white protein exerted higher antioxidant activities than other protein hydrolysates and were fractionated on the basis of the amphoteric nature of sample peptides by preparative isoelectric focusing without toxic solvents and reagents, which is termed autofocusing. Neutral and basic fractions showed higher 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity than the acidic fractions. The acidic and neutral fractions showed higher hydroxyl (OH) radical scavenging activity and oxygen radical absorbance capacity (ORAC) values than the basic fractions. The acidic fractions showed higher metal chelating activity than basic fractions. Antioxidant activities of some autofocusing fractions except for ORAC showed higher compared to the crude hydrolysate. These results suggest that peptides fractions from egg white protein are effective antioxidant, and that autofocusing could be useful to increase antioxidant activity for application to food system.

• Asian-Australasian Journal of Animal Sciences
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• 제15권11호
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• pp.1617-1621
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• 2002

Two hundred and sixteen single comb white egg layers of the White Leghorn hens of 24 weeks of age were randomly allocated to 12 groups with three replications of six hens in each. Hens were fed in a factorial arrangement 2${\times}3{\times}$2, on diets containing either 16 or 18% crude protein with 0, 3 or 6% fish meal, replacing groundnut meal with soybean meal. Soybean meal incorporation improved (p<0.05) egg production, feed intake, feed conversion efficiency and egg weights. Egg quality traits of specific gravity, shape index, albumen index, yolk index and shell thickness remained unchanged. Laying performance was significantly (p<0.05) better at 18% than on 16% dietary protein level. Use of fish meal linearly improved egg production and feed conversion efficiency on diets supplemented with groundnut meal and fish meal incorporation showed quadratic improvement on feed conversion efficiency with SBM diets at 16% dietary protein level. Therefore, use of soybean meal as substitute of groundnut meal is recommended in layer diets, at 16% dietary protein level and fish meal incorporation could be beneficial for layers.

• 한국축산식품학회지
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• 제34권3호
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• pp.362-371
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• 2014

This study utilized commercially available proteolytic enzymes to prepare egg-white protein hydrolysates (EPHs) with different degrees of hydrolysis. The antioxidant effect and functionalities of the resultant products were then investigated. Treatment with Neutrase yielded the most ${\alpha}$-amino groups (6.52 mg/mL). Alcalase, Flavourzyme, Protamex, and Ficin showed similar degrees of ${\alpha}$-amino group liberation (3.19-3.62 mg/mL). Neutrase treatment also resulted in the highest degree of hydrolysis (23.4%). Alcalase and Ficin treatment resulted in similar degrees of hydrolysis. All hydrolysates, except for the Flavourzyme hydrolysate, had greater radical scavenging activity than the control. The Neutrase hydrolysate showed the highest 2,2-azino-bis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical scavenging activity ($IC_{50}=3.6mg/mL$). Therefore, Neutrase was identified as the optimal enzyme for hydrolyzing egg-white protein to yield antioxidant peptides. During Neutrase hydrolysis, the reaction rate was rapid over the first 4 h, and then subsequently declined. The $IC_{50}$ value was lowest after the first hour (2.99 mg/mL). The emulsifying activity index (EAI) of EPH treated with Neutrase decreased, as the pH decreased. The EPH foaming capacity was maximal at pH 3.6, and decreased at an alkaline pH. Digestion resulted in significantly higher 1,1-diphenyl-2-picrylhydrazyl (DPPH) and ABTS radical scavenging activity. The active peptides released from egg-white protein showed antioxidative activities on ABTS and DHHP radical. Thus, this approach may be useful for the preparation of potent antioxidant products.

• 동아시아식생활학회지
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• 제27권3호
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• pp.280-294
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• 2017

Premix frying powders were prepared by supplementation with 0%, 3%, 6%, 9%, or 12% egg white powder. The following quality characteristics of the fried batter were assessed: proximate composition and amino acid content of premix frying powder; viscosity and pick-up ratio of frying batter; moisture content, lipid content, color, texture and DPPH radical scavenging activity; and sensory evaluation items. Addition of egg white powder in place of wheat flour resulted in lower moisture content (p<0.01) and lower carbohydrate content (p<0.001), higher crude protein content (p<0.001), higher ash protein content (p<0.001), and higher amino acid content (p<0.01) in the premix frying powder. Lower viscosity and higher pick-up ratio (p<0.001) of the frying batter were observed. The resultant fritters had the higher moisture content and higher lipid content (p<0.001). They also showed the lighter color, and had lesser redness and yellowness (p<0.001). Considering texture, the fritters were harder, had higher fracturability and higher adhesiveness (p<0.001), lower springiness (p<0.001), were less chewy (p<0.01), and had lower cohesiveness (p<0.001). Examination of DPPH radical scavenging activity showed higher antioxidant activity (p<0.001) upon addition of egg white powder. Sensory evaluation of the fried batters showed the best outcomes for the group containing 6% white egg powder, in terms of appearance (p<0.05), flavor (p<0.001), taste (p<0.01), texture (p<0.01), and overall quality (p<0.001). Based on the results of this research, we postulate that the addition of 6% egg white powder to premix frying powder will not only improve customer preference and product quality but also enhance the nutrition and functionality of the product.

• Asian-Australasian Journal of Animal Sciences
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• 제15권2호
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• pp.157-165
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• 2002

Genetic variations of seven egg white protein loci in 1,112 samples from eight Asian countries (Yunnan province of China, Mongolia, Nepal, Vietnam, Laos, Thailand, Myanmar, Indonesia) and 360 samples from two improved breeds (Isa Brown, Boris Brown) were investigated by using starch gel and polyacrylamide gel electrophoresis. Five egg white protein loci (Ov, $G_3$, $G_2$, $G_1$ and $Tf_{EW}$) were found to be polymorphic in Asian native chicken populations. The proportion of polymorphic loci ($P_{poly}$) and average heterozygosity ($\bar{H}$) of Asian native populations varied from 0.143 to 0.714 and 0.014 to 0.225, respectively, and were higher than those of improved breeds. The subdivision index ($G_{ST}$) value among 18 native chicken populations in Asia is lower (0.0827) than among improved chicken populations (0.1693). This value means that the degree of subdivision among Asian native populations is lower than among improved breeds and gene constitutions among populations in Asia are similar.