• Korean Journal of Food Science and Technology
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• v.19 no.6
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• pp.499-505
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• 1987

The functional properties of lupin seed protein concentrate (LPC) were examined and compared to those of soybean protein isolate (SPI) and Na-caseinate. LPC-50, of which protein level was 50%, was prepared by a two phase solvent (hexane: alcohol: water= 10:7:3) extraction method. LPC-70 was made from LPC-50 by removing the fractions solubilized by carbohydrate decomposing enzymes. The solubilities of LPC-50 and LPC-70 were similar to that of of SPI but slightly higher at pH 4-5, and less susceptible to the added salt. The apparent viscosity of LPC increased exponentially as the concentration increased over 6% level, and the change was similar to that of Na-caseinate. LPC showed strong pseudoplastic non-Newtonean flow behavior, which was similar to that of SPI The emulsifying capasity of LPC-70 was similar to that of SPI when salt was added. The foaming capacity of LPC was comparable to that of SPI. LPC showed high oil and water absorption capacities, which increased as the protein level was elevated. LPC-70 showed the highest oil absorption capacity of all the samples tested.

• Food Science and Preservation
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• v.11 no.4
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• pp.496-502
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• 2004

Purified acorn starch was obtained from alkali precipitation method. Acorn amylose and acorn amylopectin were fractionated from purified acorn starch by butanol improvement method. Gel permeation chromatography (GPC) was used to measure molecular weight distribution of acorn starch, acorn amylose, acorn amylopectin and corn starch, corn amylose, corn amylopectin. GPC measurement diagrams were obtained by each retention time. And then, we used DMSO and DMF as solvent, pullulan as standard material. We calculated the Number-average molar mass (Mn), Weight-average molar mass (Mw) and polydispersity from molecular weight distribution of each sample. As a result of estimating molecular weight using GPC, Mw of amylose has small value than Mw of amylopectin. From this fact, the molecular structural aspects of amylose and amylopectin were predicted and it was in good agrement with the tendency of polydispersity by GPC. The polydispersity of starch had big value than amylose and amylopectin, from this result, it might be known that the range of molecular weight appeared broad by heterogeneous properties of two components. The viscosity of purified acorn starch, amylose, amylopectin seperated from acorn starch, was decreased by increasing the shear rate and raising the temperature exponentially. Acorn starch solutions exhibited pseudoplastic power law fluid behavior.

• Microbiology and Biotechnology Letters
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• v.20 no.3
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• pp.316-323
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• 1992

Studies on the changes in rheological properties, molecular weight distribution and dextran yield after being reacted in lO%(w/w) sucrose concentration were performed with crude dextransucrase produced from Leuconostoc mesenteroides isolated from Sikhae. The reaction rate of dextran formation was monitored by sugar analysis with HPLC and by the changes in apparent viscosity. According to the periodate oxidation test, the dextran produced in this experiment was estimated to have 89% $\alpha$-(1->6) main linkages and 11% $\alpha$-(1->) side linkages. The rheological properties of the dextran solution formed changed with reaction time, and it was related to the changes in molecular weight distribution of dextran as determined by GPC analysis. As the reaction proceeded, the rheological behavior changed from Newtonian to non-Newtonian, showing Binghampseudoplastic and thixothropic flow behavior. The apparent viscosity of dextran formed solution increased with increasing reaction time, reached a maximum value of 2680 cP ($\gamma$=$33.75s^{-1}$, $25^{\circ}C$) by enzyme reaction for 8 hours, and then decreased. The temperature dependency of dextran formed solutions was well expressed by the Arrhenius equation and the activation energy reached a maximum value of 1.69 kcal/mole by enzyme reaction for 8 hours.

• Microbiology and Biotechnology Letters
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• v.35 no.3
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• pp.203-209
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• 2007

Soybean milk cake (SMC) was used for the solid-state fermentation by Bacillus subtilis PUL-A isolated from soybean milk cake. In the presence of 5% glutamate the maximum production of biopolymer (59.9 g/kg) was performed by fermentation at $42^{\circ}C$ for 24 hr. The recovered biopolymer was consisted of 87% $\gamma$-polyglutamic acid with molecular weight of $1.3{\times}10^6$ dalton and other biopolymer. The biopolymer solution showed the great decrease in consistency below pH 6.0, regardless of the molecular weight of PGA. Biopolymer solution has a typical pseudoplastic flow behavior and yield stress. The consistency of biopolymer solution was greatly decreased by increasing heating time and temperature in acidic condition compared to the alkaline condition. In kaolin clay suspension, the flocculating activity of biopolymer was the highest value with 15 mg/L biopolymer and 4.5 mM $CaCl_2$, but decreased greatly with $FeCl_3$. The flocculating activity of biopolymer was maximum at pH5, but decreased drastically by heating at $60{\sim}100^{\circ}C$. In particular, biopolymer with native PGA showed the efficient flocculating activity compared to that of modified biopolymer containing low molecular weight of PGA.

• Restorative Dentistry and Endodontics
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• v.25 no.3
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• pp.359-370
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• 2000

The purpose of this investigation was to observe the viscoelastic properties of five commercial flowable(Aeliteflo, Flow it, Revolution, Tetric flow, Compoglass flow), three conventional hybrid(Z-100, Z-250, P-60) and two condensable(Synergy compact, SureFil) resin composites. A dynamic oscillatory shear test was done to evaluate the storage shear modulus (G'), loss shear modulus(G"), loss tangent(tan ${\delta}$) and complex viscosity(${\eta}^*$) of the resin composites as a function of frequency - dynamic frequency sweep test from 0.01 to 100 rad/s at $25^{\circ}C$ - by using Advanced Rheometric Expansion System(ARES). To investigate the effect on the viscosity of resin composites of filler volume fraction, the filler weight % and volume % were measured by means of Archimedes' principle using a pyknometer. The results were as follows 1. The complex viscosity ${\eta}^*$ of flowable resins was lower than that of hybrid resins and significant differences were observed between brands. The complex viscosity ${\eta}^*$ of condensable resins was higher than that of hybrid resins. The order of complex viscosity ${\eta}^*$ at ${\omega}$=10 rad/s was as follows, Surefil, Synergy compact, P-60, Z-250, Z-100, Aeliteflo, Tetric flow, Compoglass flow, Flow it, Revolution. The relative complex viscosity of flowable resins compared to Z-100 was 0.04~0.56 but Surefil was 30.4 times higher than that of Z-100. 2. The storage shear modulus G' and the loss shear modulus G" of flowable resins were lower than those of hybrid resins but those of condensable resins were higher. The patterns of the change of loss tangent, tan ${\delta}$, of resin composites with increasing frequency were significantly different between brands. The phase angles, ${\delta}$, ranged from $30.2{\sim}78.1^{\circ}$ at ${\omega}$=10 rad/s. 3. All composite resins represent pseudoplastic nature with increasing shear rate. 4. The complex shear modulus $G^*$ and the phase angle ${\delta}$ was represented by the frequency domain phasor form, $G^*({\omega})=G^*e^{i{\delta}}=G^*{\angle}{\delta}$. The locus of frequency domain phasor plots in a complex plane was a valuable method that represent the viscoelastic properties of composite resins. 5. There was no direct linear correlationship but a weak positive relation was observed between filler volume % or weight % and the viscosity of the resin composites.

• Korean Journal of Food Science and Technology
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• v.27 no.4
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• pp.582-592
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• 1995

To measure rheological properties of the starch dough, an Extrusion Capillary Viscometer(ECV) cell was self-made and attached to Instron machine(Model 1140). Apparent viscosities of corn and waxy corn starch doughs were measured and their gelatinization degrees were determined by enzymatic analysis. When corn and waxy corn starch doughs with $36{\sim}52%$ moisture content were heated at $60{\sim}100^{\circ}C$, come-up time of the cold point of doughs decreased from 220 sec to 140 sec with increased in the moisture content. In the measurement range of $36{\sim}52%$ moisture content and $60{\sim}100^{\circ}C$ heating temperature, both corn and waxy corn starch doughs showed pseudoplastic flow behaviors. At the same shear rate, both shear stress and viscosity of starch dough decreased as the moisture content increased. At the moisture content above 44%, the shear stress and viscosity of starch dough decreased as the heating temperature increased from $60^{\circ}C\;to\;70^{\circ}C$, but increased as the heating temperature increased from $80^{\circ}C\;to\;100^{\circ}C$. When the moisture content increased and heating temperature, the gelatinization degree of starch dough increased from about 10% to about 62%. The gelatinization degree of waxy corn starch dough was $15{\sim}20%$ higher than that of corn starch dough under the same gelatinization conditions. The effects of moisture content on the viscosity of starch dough were examined by Arrhenius equation. As the moisture content increased, viscosity of starch dough decreased. But the effect of moisture content was greater in the range of $80{\sim}100^{\circ}C$ than in the range of $60{\sim}70^{\circ}C$ heating temperature.

• Journal of the Korean Society of Food Science and Nutrition
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• v.38 no.3
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• pp.352-358
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• 2009

The physicochemical properties of dextran culture fermented by Leuconostoc citreum S5 were evaluated by the addition of various polysaccharides and heat-treatment. The consistency of dextran culture increased with the addition of carrot juice residue (CJR) in submerged culture, resulting in the highest consistency of 150 $Pa{\cdot}s^n$ and viable cell counts of $2.36{\times}10^9$ CFU/mL at 20% level of CJR. The dextran culture showed the pseudoplastic behavior and its consistency was greatly increased with the addition of various polysaccharides at 2% level. Addition of glucomannan indicated the highest consistency of 1275 $Pa{\cdot}s^n$ and their heat-treatment resulted in the increase of consistency except for glucomannan. After heat-treatment, the fermented dextran culture containing CJR fortified with gellan gum and carrageenan showed great change in rheology, indicating the highest consistency and hardness value resulted in the great increase of elastic and viscous moduli. The dynamic viscoelastic properties of dextran culture were greatly increased by the heat-treatment after fortification of various polysaccharides. Thus, the consistency and viable cell counts of dextran culture were increased with the addition of CJR. The rheological properties of dextran culture were manipulated by the fortification of various polysaccharides and heat-treatment.

• Journal of the Korean Society of Food Science and Nutrition
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• v.34 no.7
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• pp.1109-1113
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• 2005

The objective of this study was to determine the effect of extrusion temperature on puffing of white and red ginseng powder. The extrusion variables were feed material (red and white ginseng powder) and die temperature $(100\;and\;115^{\circ}C)$. The analyzed characteristics of ginseng extrudates were sectional expansion index, microstructure and rheological properties. Most of biopolymer was highly puffed at higher extrusion temperature, but the cross-sectional expansion of white and red ginseng powder was higher at 1000e and longitudinal expansion seems to higher at $115^{\circ}C$. White and red ginseng powder were puffed inconsistently and discontinuously at $115^{\circ}C$. The scanning electron microphotograph of extruded white ginseng was uniform air cell distribution at 100oe, but pore size increased at $115^{\circ}C$ and had fine uniformity due to pore explosion. White ginseng and its extrudate were pseudoplastic. Intrinsic viscosity was lower as a result of increased die temperature. The cross-sectional expansion seems to be inconsistent and decreased due to decrease in melt viscosity at $115^{\circ}C$.

• Journal of the Korean Society of Food Science and Nutrition
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• v.15 no.2
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• pp.119-127
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• 1986

The rheological properties of mayonnaise were studied with cylindrindrical viscometer. It was observed that mayonnaise showed pseudoplastic behavior, yield stress and time dependent characteristics. In the initial period of shear time, the decay of viscosity of mayonnaise was followed by a second-order kinetic equation. The influence of temperature on viscosity could be described by Arrhenius equation. The apparent viscosity of mayonnaise markedly increased with an rise in the concentration of egg yolk; and the emulsion was most stable at the concentration of 12%. At the concentration of $65{\sim}75%$ oil, the apparent viscosity was increased; the maximum value was reached at 75% oil, and above 75% oil, the remarkable decreased was observed. The size of oil drops was decreased with an increase in oil concentration of 75% oil. The apparent viscosity of mayonnaise was increased with an rise in water contents, while being decreased with one in the concentration of vinegar.

• Korean Journal of Agricultural Science
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• v.14 no.1
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• pp.134-143
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• 1987

In order to observe the strawberry as the raw materials and to compare the color of strawberry's products, Hunter L,a,b tristimulate color values were measured physically by color difference meter. Food textural properties of strawberry were measured by Rheo textural meter for rheological properties of strawberry jam. According to results obtained, it showed that Hunter L,a,b tristimulus color values were affected by ripening time of strawberry and Hunter color values changed regularly on different pH. Deformation of red color pigment Hunter color values changed linearlly on different pH, therefore red color pigment of elderberry showed to be used as a food color agent. The first peak of strawberry in TPA curve was high as cherry, grape and pineapple Strawberry jam showed pseudoplastic characteristic and time dependence.