• 한국식품영양과학회지
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• 제20권5호
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• pp.509-512
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• 1991

Rheological property and apparent viscosity(η)of several semi-solid foods were measured with extrusion capillary viscometer. Apparent viscosities of several semi-solid foods ranged from 0.2714 Pa.s to 2.6453 Pa.s Rheological property of spread type semi-solid foods was pseudoplastic (with yield value). Especially, as the moisture content and temperature of Chungkook-jang spread increased, apparent viscosity decreased. On the contrary, as the added soybean oil content of Chungkook-jang spread increased, apparent viscosity also increased.

• 한국식품영양과학회지
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• 제23권5호
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• pp.822-826
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• 1994

Effects of concentration(6-9%, db) , heating temperature (80-95$^{\circ}C$), cooking time (10-50min) and heating method (continuous and instantaneous) on the apparent viscosity of cowpea sediment dispersions at 6$0^{\circ}C$ were investigated. The instantaneous heating resulted in higher apparent viscosity than continuous heating regardless concentrations and heating temperatures. The activation energy of the increase rate constant of the apparent viscosity was about 8 kcal/mole. The apparent viscosity of the cowpea sediment dispersion heated to 95$^{\circ}C$ and held for 20 min showed a linear relation with the 20 min height at 92.5$^{\circ}C$ by viscoamylograph.

• 한국식품영양과학회지
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• 제27권5호
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• pp.881-889
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• 1998

For the application of the commercially modified starch in frozen and retort foods, apparent viscosity and water loss were measured at each stages of heating, sterilization and freezing-thawing stages. Apparent viscosity showed the exponential increase with concentration and the slopes of apparent viscosity against concentration in the Firm-Tex(hydroxypropyl distarch phosphate), Hi-Flo(acetylated distarch adipate) and Colflo 67(acetylated distarch adipate) from waxy maize starch were higher than those of Amyloacetate M20(starch acetate) and X-amylo 250(distarch phosphare) from potato starch. In the presence of 1 or 2% NaCl, X-amylo 250 among modified starches showed the increase in water loss and the decrease in apparent viscosity, whereas Colflo 67, Hi-Flo and Firm-Tex were little affected by NaCl. In the presence of 1 or 2% sucrose, water loss and apparent viscosity of the modified starches were not affected. In the range of pH 4~8, water loss and apparent viscosity of the modified starches had no change but the differences were detected to some extent between each of heating, sterilization and freezing-thawing stages. In the apparent viscosity and water loss of the modified starches after 3 week storage from heating and sterilization, Hi-Flo, Amyloacetate M20 and X-amylo 250 were not changed at the storage period, and the overall acceptability of retort food containing the modified starches such as Firm-Tex and Amyloacetate M20 were favored more than others. In the apparent viscosity and water loss of the modified starches which have been frozen and thawed three times repeatedly, Colflo 67, Hi-Flo and Firm-Tex were not changed in freezingthawing, and the overall acceptability of frozen food containing Firm-Tex was most favored.

• 대한기계학회논문집B
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• 제30권1호
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• pp.67-73
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• 2006

This investigation deals with the spin-up flows in a circular container of aspect ratio, 2.0. Shear front is generated in the transient spin-up process and propagating from the side wall to the central axis in a rotating container. Propagation of the shear front to the axis in a rotating container means the region acquires an angular momentum transfer from the solid walls. Propagating speed of the shear front depends on the apparent viscosity of polymer solution. Two kinds of polymer solutions are considered as a working fluid: one is CMC and the other is CTAB solution. CMC solution has larger apparent viscosity than that of water, and CTAB shows varying apparent viscosities depending on the applied shear rates. Transient and spatial variations of the apparent viscosities of the present polymer solutions (CTAB and CMC) cause different speeds of the propagating shear front. In practice, CMC solution that has larger values of apparent viscosity than that of water always shows rapid approach to the steady state in comparison of the behavior of the flows with water. However, for the CTAB solution, the speed of the propagating of the shear front changes with the local magnitude of its apparent viscosity. Consequently, the prediction of Wedemeyer's model quantitatively agrees with the present experimental results.

• 한국융합학회논문지
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• 제10권2호
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• pp.41-48
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• 2019

본 연구는 HPMC (Hydroxypropyl methyl cellulose)의 점도와 겉보기 점도가 유탕면의 흡유량과 지방 소화율에 미치는 영향을 확인하고자 하였다. HPMC 상업용 소재의 점도와 밀가루 대체 농도가 증가함에 따라 흡유량 감소와 지방 소화 지연 효과가 나타났다. 한편, 동일한 겉보기 점도를 보이는 수준으로 밀가루 대신 HPMC를 대체하여 제조한 유탕면에서도 겉보기 점도가 같음에도 불구하고 HPMC 자체 점도 증가(높은 중합도를 갖는 시료)에 따른 흡유량 감소와 지방 소화 지연효과를 볼 수 있었다. 이상의 결과로부터, 유탕면의 흡유량 감소와 지방 소화 지연은 겉보기 점도가 동일하다 하더라도 HPMC 자체의 높은 점도가 더 주요한 영향을 주는 것을 확인할 수 있었다.

• Journal of Microbiology and Biotechnology
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• 제8권4호
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• pp.341-346
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• 1998

Optimization for the production of Pest an was followed by the Plackett-Burman Design, using modified Czapek-dox medium as the starting point. At the flask level, $K_2HPO_4$, $MgSO_4{\cdot}7H_2O$, and aeration variables positively affected the Pestan production, DCW (dry cell weight), apparent viscosity, and flocculating activity response. KCI and $FeSO_4{\cdot}7H_2O$ negatively affected the Pestan production, DCW, apparent viscosity, and flocculating activity response. Aeration variable was shown to have a positive effect on only the flocculating activity response among Pestan production, DCW, and apparent viscosity responses. In comparison of the positive and negative variables media conditions, Pestan production and flocculating activity differed by about 9 and 125 times, respectively. In particular, at the jar fermentor level, the aeration variable was the most important factor of the all responses (pestan production, DCW, apparent viscosity, flocculating activity, and anionic charge density). The flocculating activity and apparent viscosity of Pestan were closely related to the molecular chain length and charge density.

• 한국해양공학회:학술대회논문집
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• 한국해양공학회 2001년도 춘계학술대회 논문집
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• pp.196-201
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• 2001

Electro-Rheological(ER) fluids change their apparent viscosity according to the electric field strength. Therefore, there are many practical applications using the ER fluids. ER effect on the dispersive system of polarizable fine powder/dielectric oil has been investigated. The electrical and rheological properties of starch based ER fluid were reported. Yield stress of the fluids were measured on the couette cell type rheometer as a function of electric fields, particle concetrations, and temperatures. The electric field is applied by high voltage DC power supply, The outer cup is connected to positive electrode(+) and the bob becomes ground(-). And the temperatures the viscosity(or shear stress) versus shear rates were measured. In this experiment shear rates were increased from 0 to 200s$^{-1}$ in 2 minutes. This thesis presents Bingham properties of ER fluids subjected to temperature variations. The temperature dependence of the viscosity was determined for ER fluids consisting of 35 weight % starch particles in automatic transmission oil.

• 한국식품과학회지
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• 제29권6호
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• pp.1151-1157
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• 1997

정제된 다당류 메틸란을 여러 가지 화학 방법에 의해서 분석한 결과 79%의 당이 존재하였고 6%의 단백질과 16%의 유기산이 존재하였다. 배양시간이 증가함 따라 pyruvic acid와 uronic acid 같은 산의 함량이 34시간의 10%에서 72시간에서는 17%까지 증가하였고 이에 따라 점도도 증가하였다 메틸란 내의 산의 함량이 점도에 중요한 인자로 생각되어 주요 유기산인 uronic acid와 pyruvic acid의 함량과 점도와의 관계를 살펴보았다. 생물학적 및 과학적 변형을 통하여 pyruvic acid의 함량이 변화된 메틸란을 이용하여 pyruvic acid의 함량과 점도와 관계를 조사하였다. Pyruvic acid함량이 증가할수록 겉보기 점도와 고유 점도가 증가하였고 pyruvic acid의 함량이 1% 증가할 경우 약 290 cp의 겉보기 점도와 약 6 dL/g의 고유 점도가 증가하였다. 생물학적 및 화학적 변형을 통하여 uronic acid의 함량이 변화된 다당류에서 uronic acid 함량과 점도와 관세를 살펴보았다. 메틸란 내의 uronic acid의 함량이 증가할수록 점도가 증가하여 uronic acid의 함량이 1% 증가할 경우 약 85 cp의 겉보기 점도와 약 1.5 dL/g의 고유 점도가 증가하였다. 이러한 결과로부터 메틸란의 점도 증가는 다당류 내의 유기산의 함량이 증가할수록 증가되고 메밀란의 점도 증가는 uronic acid보다 pyruvic acid에 더 기인함을 알 수 있었다.

• 한국식품저장유통학회지
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• 제4권3호
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• pp.343-349
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• 1997

The rheological Voperties of biopolymers produced by Bacilli sp. K-1 and its mutant strains(KM-21, KM-83) were studied at the temperature ranges with 20∼80$^{\circ}C$, at the concenration of 2∼6%, at the pH ranges from 3.0 to 9.0 and at the shear rate of 9.3-930sec-1 The apparent viscosity of biopolymers was decreased with increasing shear rate, and thereby biopolymers showed pseudoplastic characteristics. It was found that the apparent viscosity models respected 19 temperature, concentration and both temperature and concentration were expressed by Arrhenius Model, Exponential Model and combined of the above two Models. Therefore, the apparent viscosity could be predictable by Arrhenius and Exponential Models with high R2.

• 약학회지
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• 제34권5호
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• pp.302-310
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• 1990

A study has been made of the Korean bentonite aqueous suspension contrast with American bentonite by means of XRD IR swelling, gel formation and rheogram at various conditions such as concentration, temperature and pH. The Korean bentonite was identified as montmorillonite clay containig a small proprotion of crystoballite and mordenite, and its swelling power were acceptable for requirements of Korean pharmacopeia regulations though its values were not satisfied. Korean bentonite swelled to 10 times and American one did to 15 times compared to its bulkiness of powder. The rheogram of Korean bentonite suspension reveals bulged pseudoplatic flow with yield value at higher concentration and pseudoplastic flow without yield value at lower concentration. The higher the concentration, the greater were the apparent viscosity and hysteresis loop. Korean bentonite suspension showed insignificant temperature dependence on both apparent viscosity and hysteresis loop and it was more temperature dependent on viscosity but less on hysteresis loop than those of American sample. The pH dependence was so high on viscosity that apparent minimum value was near pH 7 and maximum value at pH 3 or 7. The hysteresis loop appeared minimum over the pH range 5-7 and maximum near pH 3 or 11. The Korean bentonite was inferior to the American bentonite in swelling volume, gel formation, thioxotropy, however, it would be possible to improve the quality of Korean bentonite by developing the method of purification for bentonite clay.