• Journal of the Korean Society of Food Science and Nutrition
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• v.31 no.3
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• pp.417-422
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• 2002

Salting conditions on organoleptic properties and rheology of Chinese cabbage were optimized and monitored by four-dimensional response surface methodology. Experimental conditions were decided in the ranges of salt concentration 8∼12%, salting time 5∼25 hr and salting temperature 5∼15$^{\circ}C$. The salted Chinese cabbage with experiment design was measured on organoleptic and physical properties. The organoleptic form of the salted Chinese cabbage showed maximum score in 11.28% of salt concentration, 9.75 hr of salting time and 12.81$^{\circ}C$ of salting temperature. The organoleptic taste was maximized in 11.19% of salt concentration, 11.38 hr of salting time and 13.58$^{\circ}C$ of salting temperature. The organoleptic mouth-feel was maximized in 11.24% of salt concentration, 11.71 hr of salting time and 13.57$^{\circ}C$ of salting temperature. The organoleptic palatability was maximized in 11.52% of salt concentration, 12.86 hr of salting time and 13.07$^{\circ}C$ of salting temperature. In rheological properties of salted Chinese cabbage, hardness and chewiness decreased with the increase of salt concentration.

• Korean Journal of Food Science and Technology
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• v.22 no.2
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• pp.111-115
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• 1990

The rheological properties of soybean paste suspensions as affected by concentrations and heating were studied. All suspensions of soybean paste showed thioxotropic plastic behavior. The concentrated suspensions below the ratio of water to soybean paste, 1.25 exhibited Figure-eight phenomena which were presented by two Intersections of the up curve with the dorm curve of shear rate. The dilute suspension (soybean paste: water=1:2) showed H type hysteresis loop at low temperature. But increasing the heating temperature above $60^{\circ}C$, the hysteresis loop exhibited a Figure eight phenomenon. Consistency index of the suspensions increased remarkably by heating and showed the highest value around isoelectric point of the protein. It was suggested that the proteinous nitrogen might be the main component taking part in viscous behavior under different pH and heat treatment.

• Applied Biological Chemistry
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• v.38 no.4
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• pp.353-358
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• 1995

The influence of dry-heat treatment($130{\sim}220^{\circ}C$) on the gelatinization and rheological properties of corn starch(11.4% moisture) was examined. The enthalpy of gelatinization measured by differential scanning calorimetry decreased above $190^{\circ}C$. The viscosity of starch by alkali gelatinization increased as the heating temperature rised. All the values including peak viscosity on amylograms and shear stress, apparent viscosity, consistency index and yield stress of thermal-gelatinized starch dispersion showed decreasing tendencies with increasing of heating temperature from above $170^{\circ}C$ compared with those of raw starch. The apparent viscosity and yield stress of all the samples thermal-gelatinized at $90^{\circ}C$ were increased considerably with process of gelatinization time and especially their rapid increase at the early stage was observed in the $190^{\circ}C$ sample. But all the rheological parameters of $220^{\circ}C$ sample recorded very low values compared with those of the others.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.28 no.4
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• pp.397-400
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• 1995

Effects of rheological parameters, such as shear rate, temperature, concerntration, salts on the apparent viscosity of chitosan(deacetylation degree: $84\%$, Mw: 267,000) dissolved in acetate buffer(pH 4.5) were investigated. Rheologiral properties of chitosan solution from cuticle of red snow crab (Chinonecetes japonicus) are as follows. $0.5\%$ chitosan in 0.1M acetate buffer (pH 4.5) solution showed Bingham flow having hysteresis loop. It's flow equation was $\sigma=0.757+19.6_\gamma(r^2=0.99)$. The viscosity of chitosan solution is exponentially increased with its concentration, and showed Arrhenius dependence with respect to the temperature $(10^{\circ}C-40^{\circ}C).$ When various salts were added to chitosan solution, the viscosity decreased as the concentration of counterion increased. But the type ot counterions itself does not have any significant effects on the viscosity.

• Polymer(Korea)
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• v.31 no.6
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• pp.532-537
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• 2007

The rheological properties of the solutions of atactic poly(vinyl alcohol)(PVA) in dimethyl sulfoxide (DMSO) were investigated in terms of molecular weight distribution (MWD) of the polymer. The dynamic viscosity (${\eta}#$) and loss modulus (G") for the PVA/DMSO solutions with broader MWD were lower than those with narrower MWD at the similar $M_w$. It could be explained by the fact that the free volume for the solution with broader MWD at the similar $M_w$ was increased. The storage modulus(G#) of 14 wt% PVA/DMSO solutions with broader MWD was higher than that with narrower MWD at a lower frequency than 1.3 rad/sec, but lower than that with narrower MWD at a higher frequency (>1.3 rad/sec). The slopes of modified Cole-Cole plots of the 14 wt% solutions showed that as the MWD was broadened, the phase transition with frequency was more noticeable.

• Polymer(Korea)
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• v.38 no.2
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• pp.213-219
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• 2014

The rheological characteristics of highly concentrated polymer bonded explosive simulant were studied. Hydroxyl terminated polybutadiene (HTPB) and polyethylene plastomer (Exact) were used as binders. Sugar and Dechlorane particles whose physical properties are similar to research department explosive (RDX) were used as fillers. When HTPB was used, diethyl hexyl adipate (DEHA or DOA) was used as a plasticizer together for some cases. Highly concentrated suspensions were mixed in a batch melt mixer (Rheomixer 600, Haake) and rheological properties were measured by plate-plate and capillary rheometers. Wall slip phenomena, thixotropy with shear hysteresis, and flow instability were investigated as shear rate and amount of fillers changed.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.48 no.1
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• pp.58-63
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• 2015

The chemical and rheological properties of natural and enzymatically hydrolyzed porphyran isolated from Pyropia yezoensis were investigated. The enzymatic hydrolysate was prepared by hydrolysis of porphyran using ${\beta}$-agarase followed by fractionation based on molecular weight (>300 kDa (Fr-1), 100-300 kDa (Fr-2), 10-100 kDa (Fr-3) and 1-10 kDa (Fr-4) using an ultrafiltration membrane. Each hydrolysate fraction consisted mainly of galactose (42.7-57.5%), 3,6-anhydro galactose (6.5-15.1%) and ester sulfate (8.6-14.1%). The sulfate content of the enzymatically hydrolyzed fractions decreased with an increase in molecular weight, whereas the 3,6-anhydro galactose content increased significantly. The rheological behavior of porphyran and enzymatically hydrolyzed porphyran solutions demonstrated a pseudoplastic behavior, which agrees with the Herschel-Bulkley model. The effect of temperature on the viscosity of the porphyrans and hydolysate fractions were measured and modeled using the Arrhenius equation. The activation energy of the porphyrans and enzymatically hydrolyzed porphyran (Fr-1) increased from 12.30 to 20.29 kJ/mol and 9.06 to 23.84 kJ/mol, respectively with increasing concentrations from 3% to 7%. These data indicate that the extent of the apparent viscosity of porphyran and enzymatically hydrolyzed porphyran are influenced by both temperature and concentration.

• Korean Journal of Food Science and Technology
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• v.23 no.2
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• pp.192-199
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• 1991

The rheological properties of various flour blends of HRW-WW and DNS-WW having protein contents of $9.12{\sim}9.78%$ in the presence or absence of salt and alkaline reagent (an equal mixture of$Na_2CO_3\;and\;K_2CO_3$) were studied. The farinograph absorptions of HRW-WW and DNS-WW blends was increased by 1% and 0.6%, respectively, with increasing protein content by 0.33%. Salt (0.17%) decreased the absorption by 1% regardless protein contents. Alkaline reagent (0.17%) or a combination of salt and alkaline reagent had no effect on absorption of flours, indicating that the effect of salt on decreasing absorption is masked by alkaline reagent. The protein content of the flour in the presence or absence of salt, alkaline reagent or both showed a highly positive correlation with all reference points of farinograph and extensograph, but the peak viscosity of amylograph was negatively correlated with protein content only in the presence of salt, alkaline reagent or both.

• Korean Journal of Food Science and Technology
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• v.26 no.2
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• pp.103-109
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• 1994

Changes in the rheological properties and the linear viscoelasticity of fish protein gel upon the thermal processing were studied by using mathematical models with stress-relaxation data. The linear viscoelasticity of surimi gel was observed in the range of the true strain $0.105{\sim}0.693$ and cross-head speed $50{\sim}250\;mm/min$ applied in this study. The results of the generalized Maxwell analysis showed that the magnitudes of elastic elements $(E,\;E_e)$ were increased, but the viscous element $({\eta}) $was decreased, as the cross-head speeds and strain levels were increased. Compared to the protein gel heated directly at $90^{\circ}C$ without preheating, the protein gel pretreated at $4^{\circ}C$ and $40^{\circ}C$ showed the higher elastic modulus, but showed different trends in the viscous component, depending on the rheological model applied. Thus, the approaching methods and curve fitting of two mathematical models of stress-relaxation to describe the viscoelastic properties of fish protein gel were discussed.

• Korean Journal of Food Science and Technology
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• v.28 no.3
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• pp.538-544
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• 1996

A highly viscous biopolymer from alkali-tolerant Bacillus sp. was purified and its rheological properties were studied. 1% (w/v) solution of purified biopolymer showed pseudoplastic fluid behavior with the yield stress similar to those of xanthan and guar gum, and its consistency index was exponentially dependent on concentration and temperature. The concentration dependency of consistency index exhibited two rectilinear plots with different slopes at 1% concentration and pseudoplastic property increased with the increase of biopolymer concentration. The biopolymer solution exhibited a low temperature dependency and the activation energy of flow was 1.16 kacl/g mol. The apparent viscosity was very dependent on the change of pH and the addition of salt. However, no organic solvent effects were observed effects of viscosity synergism with the addition of viscosifier were not observed.