• 공업화학
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• 제4권1호
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• pp.196-203
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• 1993

Glycerin monostearate, polyoxyethylene(100) monostearate, polyoxyethylene(20) sorbitan monostearate를 혼합한 유화제를 분산상인 liquid paraffin, beeswax 혼합물에 용해한 후 연속상인 propylene glycol 수용액을 첨가하는 방법인 agent-in-oil법을 적용한 반전유화법에 의해 O/W 에멀젼을 제조하였고, 제조과정에서 나타나는 상거동 및 점성거동을 관찰하였다. 연속상을 주가함에 따라 액정 영역과 백타겔 영역이 존재하는 유화제 조성(HLB 10.1~12.3)에서만 미세하고 균일한 에멀젼이 형성되었으며, 유상${\rightarrow}$액정상${\rightarrow}$겔상${\rightarrow}$O/W 에멀젼으로 상변화가 일어남을 알 수 있었다. 제조된 에멀젼의 전단속도에 따른 전단응력곡선으로부터 항복치가 존재함에 따라 에멀젼 입자간의 내부구조가 형성됨을 알 수 있었고, 전단력에 의한 내부구조의 파괴가 겉보기상으로는 완전히 비가역적으로 진행되며, 구조 파괴의 척도인 hysteresis loop의 면적은 유화제의 HLB값이 작을수록 큰 것을 알 수 있었다. 시간에 따른 전단응력 변화곡선에서소성점성도의 시간의존성이 큰 것을 확인하였고, 시간유동화현상에 따른 완화시간(${\lambda}$)으로부터 HLB값이 작을수록 상대적 안정성이 큼을 알 수 있었으며, homomixer로 제조한 에멀젼에 비해 반전유화법에 의해 제조한 에멀젼이 더 안정함을 알 수 있었다.

• 한국식품과학회지
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• 제47권2호
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• pp.217-223
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• 2015

본 연구에서는 OSA-${\beta}$-glucan 유화제의 특성을 조사하기 위해 유화액을 제조하였다. 유화특성을 알아보기 위해 pH 변화, NaCl 첨가에 따른 유화액의 지방구 크기, 제타전위의 변화 등 이화학적 성질을 조사하였고, OSA-${\beta}$-glucan에 대한 co-surfactant 선정실험을 수행하였다. 그 결과, OSA-${\beta}$-glucan 유화액은 pH가 낮을수록, NaCl의 첨가량이 많을수록 응집으로 인해 안정도가 낮아지는 경향을 보였으며 이는 유화액의 제타전위 측정 및 현미경 관찰 결과와 일치하였다. OSA-${\beta}$-glucan 유화제에 적합한 co-surfactant는 유화 지방구 크기 및 크리밍 안정도 측면에서 Tween 20으로 확인되었으며 적절한 농도는 0.2% 이상으로 나타났다. 또한 Tween 20 첨가에 대한 OSA-${\beta}$-glucan 유화액의 안정도 향상은 유화지방구 표면에서 OSA-${\beta}$-glucan과 Tween 20의 co-adsorption에 기인한 것으로 추정하였다.

• Food Science and Biotechnology
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• 제17권6호
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• pp.1289-1293
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• 2008

Fresh egg yolk (EY) was enzymatically modified using phospholipase $A_2$ ($PLA_2$) to produce an enzymatically modified-egg yolk powder (EM-EYP). The EM-EYP offered significantly higher emulsifying activity, emulsion stability, protein solubility, and mayonnaise stability than the control EYP. By employing $PLA_2$ in the enzymatic modification process, structural changes occurred in the phospholipids and lipoproteins of the yolk, and cleavage of apo-high density lipoprotein (HDL) components (Mw 105 kDa) was detected by sodium dodecyl sulfate-polyaerylamide gel electrophoresis (SDS-PAGE). Based on its functional properties, EM-EYP has great potential as a replacement for fresh EY in the production of processed food products such as mayonnaise.

• Journal of Industrial and Engineering Chemistry
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• 제67권
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• pp.123-131
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• 2018

Using mixed nonionic surfactants Span/Tween, we investigated the effects of HLB value on the O/W emulsion stability and rheological behaviors. In this study, MS-01 (Span 60 & Tween 60) and MS-02 (Span 80 & Tween 80) was used as mixed nonionic surfactants. We considered required HLB value 10.85 and selected corresponding HLB value range 8-13. The droplet size distributions, droplet morphology, rheological properties, zeta-potential and creaming index of the emulsion samples were obtained to understand the mechanism and interaction of droplets in O/W emulsion. The results indicated that optimal HLB number for O/W emulsions was 10.8 and 10.7, while using MS-01 surfactant and MS-02 surfactant respectively. MS-01 (HLB = 10.8) sample and MS-02 (HLB = 10.7) sample showed smallest droplet size and highest zeta-potential value. Rheological properties are measured to understand rheological behaviors of emulsion samples. All emulsion samples showed no phase separation until 30 days storage time at $25^{\circ}C$.

• 한국식품조리과학회지
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• 제6권4호통권13호
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• pp.9-14
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• 1990

The emlsifying properties of small red bean protein isoates were evaluated through their emulsion capacity and stability of the resulting emulsions. The influence of pH, Sodium Chloride and heat treatment on the efficiency of small red bean protein isolates as emulsifying agents was studied. The surface hydrophobicity (So) of small red bean protein islates also examined. The results were obtained as follows; 1. The emusion capacity of small red bean protein isolates was high at pH 11, low at pH 3 and decreased by heat treament. With addition of NaCl, emulsion capacity decreased steadily and showed lowest value when 0.2M NaCl was added. 2. The emulsion stability at pH 4.5 and heat treatment over $60^{\circ}C$ decreased emulsion stability at pH 4.5. When NaCl was added, emulsion stability was generally increased. 3. The surface hydrophobicity of small red bean protein isolates showed the highest value at pH 3 and lowest at pH 11 and increased as the heating temperature increased When 0.2 M NaCl was added, surface hydrophobicity also increased at pH 4.5.

• 한국식품조리과학회지
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• 제7권3호
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• pp.53-59
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• 1991

This study was carried out in order to investigate the change of protein functionalities such as foaming and emulsifying properties by succinylation of protein isolates. Succinylated and unsuccinylated munghean protein isolates were tested for finding out the effects of pH, heat treatment and sodium chloride concentration on the solubility, emulsion capacity, emulsion stability, foaming capacity, and foam stability. The results are summarized as follows: 1. Succinylation enhanced the solubility of MPI except at pH 4.5. When heated, succinylation greatly increased the solubility of succinylated MPI above $60^{\circ}C$. With the addition of NaCl, succinylation increased the solubility of MPI at acidic condition. 2. Emulsion capacity of succinylated MPI showed the lowest value at pH 7 and higher values at acidic and alkaine condition. when succinylated MPI was heated, emulsion capacity showed the highest at $80^{\circ}C$. With NaCl was added, emulsion capacity of succinylated MPI lincreased at pH 7, 9 or 11 decreased at pH 3 except addition of 1.0M NaCl. 3. Emulsion stability of MPI and succinylated MPI showed the highest at pH 4.5. Succinylation enhanced the emulsion stability of MPI at acidic condition. 4. The foaming capacity of MPI was increased at pH 3, 7 or 9 by succinylation. 5. When heated, foam stability of MPI and succinylated MPI showed the highest at pH 4.5 and at pH 11, respectively. When heated, both proteins showed the highest stability at $100^{\circ}C$.

• 한국식품조리과학회지
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• 제15권1호
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• pp.73-80
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• 1999

This study was carried out to investigate the effects of enzyme treatments on the functional properties of soy protein isolate (SPI) and to examine the quality attributes of soy yogurt prepared by different enzyme treatments, sweeteners and starter cultures. Enzyme treatment increased the solubility and emulsifying capacity of soy proteins, but decreased the emulsifying stability; the enzymatic activity of ${\alpha}$-chymotrypsin was higher than that of trypsin. Enzyme treatments decreased the pH of soy yogurts prepared by both culture methods, the culture of L. bulgaricus and S. thermophilus and the culture of L. bulgaricus and K. fragilis, but increased the titratable acidity, total numbers of lactic acid bacteria and yeast. Trypsin was more effective than ${\alpha}$-chymotrypsin in decreasing pH and increasing titratable acidity and total numbers of lactic acid bacteria and yeast. Fructose decreased the pH of soy yogurts more than sucrose in the culture of L. bulgaricus and S. thermophilus, and vice versa in the culture of L. bulgaricus and K. fragilis. Fructooligosaccharides were more effective in the culture of L. bulgaricus and K. fragilis than in the culture of L. bulgaricus and S. thermophilus in increasing the titratable acidity, total count of lactic acid bacteria and yeast. In sensory evaluation, soy yogurts containing trypsin treated SPI, fructose and fructooligosaccharides (75%:25%) were more acceptable than those containing untreated or trypsin treated SPI and fructose. This was because of more smooth and less sour, in which the values of pH, titratable acidity, microbial growth, and viscosity were in the range of commercial yogurts. Soy yogurts fermented by L. bulgaricus and K. fragilis showed more smooth mouthfeel than those fermented by L. bulgaricus and S. thermophilus.

• Journal of Microbiology and Biotechnology
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• 제16권5호
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• pp.716-723
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• 2006

A biosurfactant-producing bacterial strain was selected from oil-contaminated soil because of its ability to degrade crude oil and tributyrin $(C_{4:0})$. The strain was identified as Bacillus subtilis A8-8 based on its morphological, biochemical, and physiological characteristics. When B. subtilis A8-8 was grown with crude oil as the sole carbon source, the biosurfactant from the strain emulsified crude oil, vegetable oil, and hydrocarbons. Soybean oil was the optimum substrate for the emulsifying activity and emulsion stability of the biosurfactant, both of which were superior to those of several commercially available surfactants. The biosurfactant was purified by a procedure including HCl precipitation, methanol treatment, and silica-gel chromatography. The partially purified biosurfactant was analyzed by TLC (thin-layer chromatography), SDS-PAGE, and HPLC and it reduced the surface tension of water from 72 mN/m to 26 mN/m at a concentration of 30 mg/l. Therefore, the purified lipopeptide biosurfactant has strong properties as an emulsifying agent and acts as an emulsion-stabilizing agent.

• 한국응용과학기술학회지
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• 제30권4호
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• pp.779-789
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• 2013

This study aimed to investigate the emulsifying properties of bovine lactoferrin in food emulsion system. First, lactoferrin solution was prepared to study its surface activities, such as surface adsorption characteristics and ${\zeta}$-potential. Second, some physicochemical properties of lactoferrin emulsion which resulted from variations of environmental conditions (i.e., pH or NaCl addition) were determined. As for surface adsorption characteristics evaluated by surface tension, it was decreased with increasing lactoferrin concentration in solution ($1{\times}10^{-5}{\rightarrow}0.2wt%$) and showed a plateau (${\fallingdotseq}44$mN/m) above 0.01 wt%. It was also changed with pH and the minimum value of 53.8 mM/m was observed at pI of lactoferrin. This was related to changes in ${\zeta}$-potential of the lactoferrin solution with respect to pH. Fat globule size of lactoferrin emulsion was decreased with increasing lactoferrin concentration and a stable emulsion was formed above 0.5 wt% lactoferrin in emulsion with fat globule size $d_{32}$ of ca. 0.33 ${\mu}m$ as confirmed by creaming stability experiment (i.e., Turbiscan). As with surface tension, fat globule size of lactoferrin emulsion also changed with pH and showed a maximum value at pI. As evaluated by Turbiscan, in the presence of NaCl, the lactoferrin emulsion showed instability in particular above 10 mM.

• Preventive Nutrition and Food Science
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• 제5권4호
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• pp.200-204
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• 2000

Protein conjugation of curdlan belonging to $\beta$-1, 3-glucan was carried out to improve it surface functionalities. The glucan was mixed with phosvitin, {TEX}$$\alpha$_{s}${/TEX}-casein, lysozyme or ovalbumin, respectively. The mixture was freeze-dried, and he resulting powder was incubated at 6$0^{\circ}C$ and 79% relative humidity for 12 days in order to generate a controlled Maillard reaction between curdlan and proteins. conjugation with unfolding proteins, i.e., phosvitin and {TEX}$$\alpha$_{s}${/TEX}-casein, drastically increased the solubility of the glucan, whereas lysozyme and ovalbmin did not. The solubility in water of curdlan was 3.44% for the phosvitin conjugate and 1.09% for the {TEX}$$\alpha$_{s}${/TEX}-casein conjugate. SDS-slab polyacrylamide gel electrophoresis showed that curdlan was solubilized due to covalent binding with phosvitin. Emulsifying properties of curdlan were substantially improved by the conjugation with phosvitin and {TEX}$$\alpha$_{s}${/TEX}-casein. Emulsion stability of the curdlan-phosvitin conjugate was about 2.9 times greater than that of the curdlan-phosvitin mixture.