• Applied Biological Chemistry
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• v.32 no.4
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• pp.327-331
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• 1989

In this study the Theological properties between C1-treated soft wheat flour and untreated soft wheat flour was determined. Chlorine treatment lowered pH of the flour in a linear fashion. Water absorption and dough stability was high in proportion to the increase of treatment level but mechanical tolerance index was reduced by each increment of chlorine. The valorimeter value did not exhibit reproducible trend on treatment of chlorine. In general, resistance(BU), resistance to extension and maximum viscosity(BU) were highest in control group; lowest in 1 oz./cwt. flour and tended to rise in 2 oz./cwt. flour when it fermented in chamber for 90 min and 135 min. The maximum viscosity was highest (1,160BU) in 4 oz./cwt. flour and temperature at maximum viscosity tended to rise gradually in proportion to the increase of treated level.

• Korean Journal of Food Science and Technology
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• v.20 no.6
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• pp.850-855
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• 1988

Rheological propreties of defatted and 1% palmitic arid reincorporated rice starch solutions were investigated, comparing with nondefatted starch. Flow behavior of gelatinized starch solutions(3-7%) revealed pseudoplastic behavior with yield stress, but yield stress was decreased by defatting. Relationship between logarithmic consistency index and concentration of nondefatted starch solution was linear with single slope, but the slopes for defatted and reincorporated starch solutions were different at 3-5% and 5-7% starch concentration. The activation energies for 7% starch solutions were estimated to be 3.14-4.76 kcal/g mol and increased slightly by defatting. All thre starch solutions above 4% concentration exhibited hysteresis phenomena, but by defatting, humping phenomena was observed and thixotropic behavior were increased slightly.

• Korean Journal of Food Science and Technology
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• v.19 no.3
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• pp.239-244
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• 1987

Rheological properties of 5% starch suspension were investigated using a capillarity tube viscometer. Nonglutinous and glutinous rice starch suspensions at $30-60^{\circ}C$, and $30-55^{\circ}C$, respectively, had no yield stress and showed dilatant flow behavior in the absence or presence of phosphate. However, flow behavior of nonglutinuous starches at $65^{\circ}C$ and glutinous starch at $60^{\circ}C$ was pseudopalastic. Flow activation energies for rice starch suspensions were 0.88-1.45 kcal/mole at $30-50^{\circ}C$ and about 45-73 kcal/mole $60-65^{\circ}C$. Flow activation energy in the presence of phosphate was 90-182 kcal/mole at $60-65^{\circ}C$. Akibare starch had the highest activation energy, and glutinous starch the lowest.

• Korean Journal of Food Science and Technology
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• v.20 no.6
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• pp.812-819
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• 1988

Rheological properties of rehydrated suspensions of freeze dried tomato ketchup were measured by Brabender Viscotron at the temperature range of $30-90^{\circ}C$, at the concentration of 15-50%, and at the shear rate of $0-250sec^{-1}$. At the shear rate of $0-210sec^{-1}$, tomato ketchup was found to be a thixotropic food product. The values of flow behavior index, consistency index and yield stress at the shear rate of $0-210sec^{-1}$, at the temperature of $30^{\circ}C$ and at the concentration of 33% , were 0.2131, 22.5047 $Pa\;sec^{-n}$, and 8.544 Pa, respectively. It was found that the apparent viscosity model for temperature was expressed by Andrade model and the model for concentration was expressed by Power model, and the model for both temperature and concentration was described by exponential and power models. The activation energies at the concentrations of 15, 20, 30, 33, 40, and 50% were 3.973, 4.985. 5.078, 5.226, 5.357, and 7.655 $kcal/g{\cdot}mole$, respectively.

• Applied Biological Chemistry
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• v.36 no.6
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• pp.416-423
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• 1993

Milk powders were made by several drying methods and raw materials, and rheological properties of milk powders were investigated by an Instron Universial Testing Machine. The results obtained are summarised as follows. Bulk density of the drum dried whole milk powder was $0.382\;g/cm^3$ and was higher than that of other milk powders. The Hausner ratio, angle of repose and compressibility of the spray dried skim milk powder were 1.127, $32.5^{\circ}$ and 0.029 respectively. This result indicated that skim milk powder showed free flowing characterristics. The compressibility of the drum dried whole milk powder was decreased by the decrease of moisture content. Compressibility of the milk granule was 0.056 and was lower than that of milk powder. The spray dried milk powder of a grobular shape had higher solidity than the freeze or drum dried milk powder. The drum dried milk powder particles consist of irregular shape.

• 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.

• Korean Journal of Food Science and Technology
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• v.18 no.4
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• pp.278-282
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• 1986

Rheological properties of naked barley (Songhak and Youngsan) starches were compared. The gelatinized starches at $3{\sim}9%$ concentration showed a Bingham pseudoplastic behavior. Songhak starch had higher values of consistency index and yield stress than those of Youngsan starch. The dependence of consistency index on concentration was mere pronounced in Songhak starch. Consistency index of both starches was exponentially dependent on concentration, but the slopes at $3{\sim}5%\;and\;5{\sim}9%$ starch concentration were different. The activation energies of 7% for Songhak and Youngsan starches were 4.10 and 3.71 Kcal/mole, respectively.

• 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.23 no.5
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• pp.642-645
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• 1991

The rheological properties of wheat flours and corn starch and cooking properties of dry noodle in the presence of calcium phosphate hydroxyapatite(Ca-P) were studied. The additive($0.2{\sim}0.8%$) had essentially no effects on farinograms of strong and all-purpose wheat flours, however, they decreased the amylograph pasting temperature and increased the peak viscosity of flours, which was more pronounced in all-purpose flour. The cooking properties of dry noodles in the presence or absence of the Ca-P showed no significant differences, but the cutting forces of cooked noodles were increased by Ca-P at 0.4%. The pasting properties of corn starch in the presence of Ca-P($0.2{\sim}0.8%$) were similar to those of wheat flour. The gelatinization temperature of corn starch by differential scanning calorimeter decreased by $1^{\circ}C$ in the presence of 0.4% Ca-P. The time constant, a reciprocal of rate constant, of corn starch gel was slightly increased in the presence of 0.2 or 0.4% Ca-P.

• Korean Journal of Food Science and Technology
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• v.21 no.6
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• pp.755-759
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• 1989

Starches obtained from Seipoong and Daeji potato were classified into go starch granules $(>41{\mu}m)$ and small starch granules $(<3{\mu}m)$. Rheological properties of heat-gelatinized starch paste were studied to elucidate difference of the fractionated starches. Heat-gelatinized starch paste of potato showed Bingham pseudo-plastic behavior. The consistency index and yield stress of small starch granule paste were greater than those of large starch granule paste. As starch paste concentration increased, consistency index and yield stress of heat-gelatinized small starch granule paste increased more than those of large one. As measuring temperature increased, consistency index of heat-gelatinized starch paste decreased and temperature depedence was greater in small starch granule paste than in large one.