• Korean Journal of Food Science and Technology
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• v.24 no.6
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• pp.619-622
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• 1992

To increase utilization of Korean yam, the rheological properties of gelatinized yam (Dioscorea aimadoimo) starch solutions at various concentrations $(1{\sim}5%)$ and temperature $(30{\sim}60^{\circ}C)$ were investigated. The rheological behavior of gelatinized yam starch solutions was illustrated by power-law model and Casson equation and exhibited pseudoplastic behavior with yield stress. The pseudoplasticity of starch solutions increased largly concentration of starch increased. As the temperature increased from $30^{\circ}C$ to $60^{\circ}C$, the dependency of starch concentration decreased, B were decreased from 0.40449 to 0.39352. The activation energy of flow of gelatinized yam starch solutions were increased from 4.1415 to $5.45329{\times}10^6\;J/kg{\cdot}mol$ by increasing starch concentration from 1% to 5%.

• Korean Journal of Food Science and Technology
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• v.12 no.1
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• pp.18-23
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• 1980

Rheological behaviors of red pepper paste acre investigated with rotational viscometer at $25{\sim}55^{\circ}C$ and the following results were obtained. 1. At shear rate of $0.323{\sim}1.653\;sec^{-1}$, red pepper paste was found to be a thixotropic food product which showed pseudoplastic proper ties and also exhibited a yield stress and time dependent characteristics. 2. At a shear rate of 0.978 $sec^{-1}$, flow behavior index, consistency index and yield stress were 0.597, 192.3 dyne $sec^s/cm^{2}$, and 91 dyne/$cm^{2}$ respectively. 3. Variation of consistency of red pepper paste with time was found to be decayed by a second order kinetic equation and thereafter nearly time independent. 4. Variation of consistency of red pepper paste with temperature was found to follow Andrade's equation and the activation energy as calculated on the basis of this equation was $1.03\;kcal/g{\cdot}mole$.

• Food Science of Animal Resources
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• v.38 no.5
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• pp.866-877
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• 2018

Cheese emulsion is an intermediate product for the production of cheese powder and needs to be stable, homogeneous and pumpable characteristics to convey to the spray drier. This study was conducted to evaluate the effects of fat reduction and emulsifying salt (ES) amount in cheese emulsion systems on the physicochemical characteristics. Reduced-fat (RF) and full-fat (FF) white-brined cheese emulsions were produced with different dry matters (DM; 15%-25% excluding ES) and ES concentrations (0%-3% based on cheese weight). Stable cheese emulsion was obtained at lower DM in RF cheese emulsion than that of FF cheese emulsion. Reduction in the amount of ES resulted in instability of both emulsions. Apparent viscosity with pseudoplastic flow behavior significantly increased with the decrease of fat content in stable cheese emulsions. Microstructure of emulsions appeared to be related to the fat content, stability and degree of emulsification. Reduction of fat content caused to get less lightness and more greenness in color, whereas yellowness was significantly decreased by increase in the amount of ES. In conclusion, fat reduction resulted in higher viscosities of cheese emulsion due to inducing the increment of protein, and the addition amount of ES considered as very important factor to produce stable cheese emulsion without protein precipitation or cream separation. Therefore, for preparation of RF cheese emulsion using a variety of white-brined cheese, lower amounts of DM would be suggested in this study to obtain homogenous droplets in the atomizing process of spray drying.

• Korean Journal of Food Science and Technology
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• v.31 no.4
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• pp.1132-1136
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• 1999

This study was performed to offer fundamental data for concentration of persimmon vinegar. The $5.4^{\circ}Bx$ raw persimmon vinegar was concentrated to $20^{\circ}Bx$, $30^{\circ}Bx$, $40^{\circ}Bx$, $50^{\circ}Bx$, $60^{\circ}Bx$ and $70^{\circ}Bx$ concentration by vacuum concentration at $55^{\circ}C$ and diluted to $5.4^{\circ}Bx$ solution with distilled water. The physicochemical properties such as color, viscosity, pH, acidity, organic acid content and free sugar content of various persimmon vinegar concentrates were examined. The recovery yield of water soluble solid to concentrates was 55.5% on $20^{\circ}Bx$ vacuum concentration. Color of $5.4^{\circ}Bx$ persimmon vinegar diluents from concentrates became more dark brown by vacuum concentration. Flow behavior of persimmon vinegar concentrates was pseudoplastic. As the concentration of persimmon vinegar concentrates increased, pH of $5.4^{\circ}Bx$ diluents increased and acidity as acetic acid decreased compared to original raw vinegar. Acetic acid, lactic acid and citric acid were detected, malic acid and oxalic acid were not detected in persimmon vinegar concentrate. Fructose and sucrose only were detected in persimmon vinegar concentrate.

• Journal of Pharmaceutical Investigation
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• v.26 no.3
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• pp.221-232
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• 1996

An abrasive, calcium hydrogen phosphate dihydrate (DCPD), was synthesized in a Box-wilson experimental design by reactions between phosphoric acid and milk of lime, and calcium chloride and sodium phosphate solutions, and stabilized with TSPP and TMP. The optimum conditions for preparation of DCPD from phosphoric acid with milk of lime were such as; reaction temp.; $51.9^{\circ}C$, conc. of lime; 25.9%, conc. of phosphoric acd; 77.9%, drying temp.; $60.2^{\circ}C$ and final pH; 6.46. The physico-chemical and pharmaceutical properties of DCPD were showed as follows: glycerin absorption value(68 ml/100g), whiteness(99.5%), particle size(10.9 nm), pH(7.8), and set test(pass). XRD and SEM of DCPD indicated a monoclinic system crystallographically. $N_2$ adsorption isotherm curve by BET showed non porous type II form. The micromeritic parameters of DCPD showed that surface area was $3.27{\sim}4.6\;cm^{2}/g$ and pore volume, pore area and pore radius were negligible. The rheogram of the toothpaste containing DCPD showed pseudoplastic flow with yield value of 321, and thixotropic behavior forming hysteresis loop. These results meet the requirements as abrasive standard, and sythesized DCPD is expected as a good dental abrasive such as a high quality grade in practice.

• Korean Journal of Food Science and Technology
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• v.16 no.1
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• pp.11-16
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• 1984

Rheological properties of waxy and non-waxy rice starch solutions were evaluated with a narrow gap rotational and Cannon Fenske viscometers. The gelatinized rice starch solutions containing 0.2-1.0% starch displayed pseudoplastic flow behavior. At higher starch level, degree of pseudoplasticity of waxy rice starch solutions increased, while that of non-waxy rice did not changed apparently. The consistency coefficient (K) of non-waxy rice starch solutions increased with increasing gelatinization temperature, but waxy rice starch solutions remained constant, and in alkaline aqueous solutions both of them showed increasing K values. The value of K increased exponentially with an increase in concentration. The effect of the temperature on the viscosity of the solutions followed Arrhenius' type equation, and the activation energies were in the range of 3.675-3.775 kcal/g-mol that were near to that of pure water. The changes of reduced viscosity with concentration were followed Huggin's equation and the values of intrinsic viscosity and interaction coefficient were 0.78-1.59 dl/g and 0.67-2.75, respectively.

• Korean Journal of Food Science and Technology
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• v.20 no.4
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• pp.470-475
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• 1988

The extrusion-cooking method was used to make gelatinized rice extrudate from rice grits of the Chuchung and the Samgang varieties. The water contents of raw rice grits varied from 15% to 25%, and the physicochemical properties of extrudates were evaluated. Low moisture content showed high expansion ratio in rice extrudate and resulted in some decrease in gelatinization, bulk density and break strength. Increasing the water content to 25% resulted in increase in water absoption index but decrease in water solubility index. With regards to Brabender Amylograph values and rheological patterns, higher moisture content in raw materials revealed stronger pseudoplastic flow behavior with lower viscogram property. Hunter's color values of rice flours extruded at low water content were low in b values. Scanning electron microscopy demonstrated the break-down of starch granules during extrusion.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.30 no.3
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• pp.329-333
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• 1997

Rheological properties of partially purified fucoidans of Laminaria religiosa, sporophylls of Undaria pinnatifida, Hizikia fusiforme, and Sargassum fulvellum in Korea were investigated, The fucoidans produced aqueous solutions of low apparent viscosity with pseudoplastic flow behavior. The viscosity of $5\%$ solution of the fucoidan from sporophylls of U. pinnatifida was 2.2 mPa.s. The activaton energies of L. religiosa, sporophylls of U. pinnatifida, H. fusiforme and S. fulvellum were $8.269\times10^6,\;7.498\times10^6,\;7.141\times10^6,\;and\;6.677\times10^6\;J/Kg.mol$ at 1,500 1/s of shear rate, respectively. The viscosity of the fucoidan solution was increased by the addition of sugar, but that was not changed by addition of NaCl.

• Korean Journal of Food Science and Technology
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• v.24 no.6
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• pp.574-580
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• 1992

Chitin was isolated from the residue of enzymatically hydrolyzed crab, Portunus trituberculatus, and further deacetylated by alkaline boiling to make chitosan. The physical properties of chitosan solution and its film forming properties were examined. The functional characteristics of chitosan film were compared to those of cellophane, polyvinyl chloride (PVC) and polyethylene (PE) films. The proximate chemical composition of chitin obtained from crab residue was 6.95% nitrogen, 0.3% crude ash and 4.57% moisture and the product yield was 12.8% based on a dry material basis. The degree of deacetylation of chitosan was $79{\sim}92%$ and $70{\sim}86%$ as determined by IR spectroscopy, and $70{\sim}86%$ as determined by colloid titration method each respectively. The chitosan at 1% acetic acid solution showed distinct pseudoplastic flow behavior. The flow behavior index and consistency index were 0.8886, 0.2084 $MPa{\cdot}s^n$ for 0.4% solution and 0.8498, 0.6190 $MPa{\cdot}s^n$ for 0.8% solution, respectively. The chitosan film had the highest tensile strength $(888 kg/cm^2)$ and water permeability $(100\;g/m^2{\cdot}24\;hrs)$ among the tested films, but relatively low elongation property (49%). It showed the similar tear strength (90kg/cm) and light permeability (87.7%) to other films tested in spite of the relatively high haze value (12.5%). As the thickness of chitosan film increased from 0.025 to 0.050 mm, the tensile strength of film decreased distictively, and the degree of elongation, tear strength, and water permeability of film also decreased slightly. Whereas the light permeability of film did not change and the haziness of film slightly increased by the increase of film thickness.

• Korean Journal of Food Science and Technology
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• v.26 no.4
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• pp.442-447
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• 1994

Effect of different mixing ratio of non-glutinous and glutinous rice on physical and rheological properties of extrudate prepared in a single screw extruder were examined. The extrusion conditions in term of screw speeds, moisture content and die temperature were 258 rpm, 18% and $120^{\circ}C$, respectively. The resisdence time distribution of the most of materials were within 30 second and small portion of them went up to 80 second. The expansion ratio was the highest value (2.93) for 70% of glutinous rice in the mixture, while the lowest value for 100% of non-glutinous rice. Breaking strength was in the range between 1,051g and 1,117g for $10{\sim}20%$ of glutinous rice in the mixture, while the lowest value (737g) for 80%r of glutinous rice. As the amount of glutinous rice increased, L and a values were increased and b value was decreased. The uncooked cold paste viscosity had 400 B.U. for 100% non-glutinous rice , while no peak for the 100% glutinous rice. As the amount of glutinous rice increased up to 100%, the water absorption index (WAI) was decreased, while water solubility index (WSI) was increased. The rheological properties of extrudate were accounted by the law of Oswald. The flow behavior index of extrudate was less than 1.0, which showed pseudoplastic behavior. Yield stress was the highest value for 20% of glutinous rice in the mixture and the lowest value for $80{\sim}100%$ of glutinous; rice. Number of air cell was between 128 and 159 for $80{\sim}100%$ of glutinous rice in the mixture, while $81{\sim}84%$ for $0{\sim}20%$ of glutinous rice. The degree of shapefact was increased more when the mixtures of glutinous and non-glutinous rice was used than when glutinous or non-glutinous rice was only used.