• Macromolecular Research
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• v.10 no.2
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• pp.115-121
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• 2002

Synthesis of polymers with controlled thermosensitive properties was carried out by conventional radical copolymerization of N-isopropylacrylamide (NIPAAm) with N-vinylpyrrolidone (NVP) taken as a hydrophilic comonomer. Lower activity of NVP rather than NIPAAm was revealed by gravimetric and $^1$H NMR analysis. Thermosensitive properties of the copolymers were investigated. It was found that aqueous solutions of the copolymers undergo thermo-induced phase transition and become opaque, precipitate or gel with heating. After formation of the gels their significant contraction was observed at storage. Swelling degree and amount of expelled water were measured in dependence on the copolymer composition, temperature and ionic strength of environment medium and concentration of the solution. It was determined that in collapsed state gels exhibit quite high water content. According to physico-chemical properties of the copolymers observed they could be suitable for biomedical application as an injectable implant material.

• Fisheries and Aquatic Sciences
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• v.17 no.3
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• pp.299-304
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• 2014

The objective of this study was to elucidate the physicochemical characteristics of gelatin extracted from jellyfish Rhopilema hispidum. We investigated the proximate composition, amino acids, gel strength, gelling/melting points, dynamic viscoelastic properties, and viscosity of jellyfish gelatin. Jellyfish gelatin contained 12.2% moisture, 1.5% lipid, 2.1% ash, and 84.8% protein. Glycine, hydroxyproline, proline, and alanine were the predominant amino acids. The gelatin showed a gel strength of 31.2 kPa, a gelling point of $18.0^{\circ}C$, and melting point of $22.3^{\circ}C$. The gelatin was composed of ${\alpha}_1$-chain, ${\alpha}_2$-chain, ${\beta}$-chain, and ${\gamma}$-chain. During cooling and heating process, jellyfish gelatin showed lower elastic modulus (G') and loss modulus (G") values than mammalian gelatin. Jellyfish gelatin did not show superior rheological properties to mammalian gelatin, like other fish gelatin; however, it can be used in various food and cosmetic products not requiring high gel strength.

• Korean Journal of Food Science and Technology
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• v.2 no.2
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• pp.49-55
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• 1970

In preparation of textured soybean protein, drying process of the isolated protein affected its gelling property and other related characteristics such as water holding capacity and viscosity. In model systems, denaturation of the protein, as determined in terms of nitrogen solubility index (NSI), was appeared to be a parameter of the gel strength of soybean protein isolate. The gel strength was maximum when the protein was denatured properly during drying process of which the NSI was 43 in this experiment and decreased at either the higher or the lower NSI. It indicated that proper denaturation of the protein during drying operation is advantagous for the preparation of textured soybean protein but not neccesary to make highly undenatured one.

• Journal of the Korean Society of Food Science and Nutrition
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• v.21 no.6
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• pp.738-747
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• 1992

The important legumes in Korea are mungbean, red bean, kidney bean and cowpea. Mungbean has traditionally been used for mook (jelly-like starch gel) preparation. Cowpea has recently been utillized for substitution of mungbean. The major use of sediment of red bean is for the sweet paste. The studies related to legume starches and flours (air-dried sediment) in Korea are concentrated on the understanding of the properties of mook. The structure of starch, gelatinization and gelling properties of legume starches and flours are reviewed with emphasis of Korean literatures.

• Korean Journal of Plant Resources
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• v.17 no.1
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• pp.43-47
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• 2004

The effect of plant growth regulators and gelling agents for plant regeneration from leaf segment of Chrysanthemum zawadskii ssp. coreanum was investigated. NAA was more effective than BA for plant regeneration. MS medium supplemented with NAA 1 mg/L was the most effective in plant regeneration. The effect of agar and gelite as gelling agent was compared. Agar(0.8%) was more effective than gelite(0.2%) in plant regeneration. Regenerated shoots was successfully increased by shoot grafting in MS medium supplemented with NAA 0.1 mg/L in vitro, and hardened by shoot grafting in artificial soil mix(Peatmoss : Perlite = 1 : 1).

• Culinary science and hospitality research
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• v.19 no.1
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• pp.151-163
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• 2013

The purpose of this study was to examine the optimization and quality characteristics of balsamic vinegar jelly by the addition of various gelling agents: agar, gelatin, arrowroot starch, potato starch. For this purpose, mechanical tests(moisture content, color value, pH, sugar content, texture) and sensory tests(quantitative descriptive analysis & acceptance test) were conducted, showing the following results. The moisture content of balsamic jelly was the highest in the gelatin addition group, the color intensity of the L value in the potato starch addition group, redness a value in the gelatin addition group, and the b value(yellowness) in the agar addition group. The pH of balsamic jelly was the highest values in the gelatin addition group while its sugar content was the highest values in the arrowroot starch addition group. As a result of measuring balsamic jelly texture, there were significant differences in hardness, chewiness and gumminess by gelling agents. In the quantitative descriptive analysis of sensory test, the gelatin addition group showed the most high level in purple color intensity, glossiness, transparency, and chewiness. As for the acceptance in the sensory test, the gelatin addition group showed the most high level in appearance, taste, texture, and overall acceptance, which also had a significant difference. In case of balsamic flavor, Arr added arrowroot starch showed the highest values, which also had a significant difference. The result of this study showed that the gelatin addition group made a positive acceptance and improvement of sensory and machinery quality characteristics.

• Korean Journal of Plant Tissue Culture
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• v.25 no.1
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• pp.63-68
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• 1998

Multiple shoots obtained in MS medium suppler with 5.0 mg/L BA though shoot-tip culture. The frequency of vitrified shoot was lower on Bacto-agar medium than on Gelrite as gelling agent. Addition of activated charcoal at concentrations of 0.1~0.3% reduced vitrification and markedly increased shoot growth, and formation and growth of roots, but significantly reduced the number of shoots formed. The ratio of fresh weight to dry weight was decreased by increasing light intensity and agar concentration. Eight-tenths times of macroelement of MS medium was observed to be effective for shoot formation. Addition of IAA effectively promoted shoot formation in both shoot tip and node-bud explants. Supplement of 5.0 mg/L BA, 0.3 mg/L IAA to MS medium was most effective in shoot proliferation on shoot tip and node-bud explants.Multiple shoots obtained in MS medium suppler with 5.0 mg/L BA though shoot-tip culture. The frequency of vitrified shoot was lower on Bacto-agar medium than on Gelrite as gelling agent. Addition of activated charcoal at concentrations of 0.1~0.3% reduced vitrification and markedly increased shoot growth, and formation and growth of roots, but significantly reduced the number of shoots formed. The ratio of fresh weight to dry weight was decreased by increasing light intensity and agar concentration. Eight-tenths times of macroelement of MS medium was observed to be effective for shoot formation. Addition of IAA effectively promoted shoot formation in both shoot tip and node-bud explants. Supplement of 5.0 mg/L BA, 0.3 mg/L IAA to MS medium was most effective in shoot proliferation on shoot tip and node-bud explants.

• The Korean Journal of Food And Nutrition
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• v.10 no.2
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• pp.234-240
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• 1997

Agar has widely been used as medical aids and food ingredients due to its pecular physicochemical and rheological properties. In this paper, the effects of spray drying and extrusion drying on functional properties of agar were investigated to clarify the sol-gel transition mechanism at low temperature and microstructure of agar gel by measuring phase transition by differential scanning calorimetery, structural differences by light microscope and scanning electron microscope observation. The lowest endothermic onset(To), peak(Tp), conclusion(Tc) temperature and enthalpy($\Delta$H) using differential scanning calorimetery were showed in extrusion-dried agar wic were checked in 41.30, 61.72, 80.50 and 0.73cal/g. In cases of unmodified and spray-dried, the values were 81.20, 95.51, 112.14 and 3.22cal/g, and 60.11, 76.45, 89.54 and 1.53cal/g, respectively. When all samples were reheated using differential scanning calorimetery after gelling fully, no significant differences of endothermic To, Tp, Tc and $\Delta$H appeared. The surface structure of unmodified agar powder observed by light microscope and scanning electron microscope appeared a continuous surface without any indication of small pores, gaps or point of discontinuity. In cases of spray-dried agar, the unstable structures with pores was resulted. The microstructures of extrusion-dried agar, however, was solid with large gaps and areas of discontinuity in the surface. From the results above, it was suggested that significant differences in phase transition and surface microstructures were clearly related to the physicochemical changes and rheological properties, solubility and gelling ability of the types of agar gel.

• Journal of Pharmaceutical Investigation
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• v.26 no.3
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• pp.187-192
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• 1996

The matrix tablet containing sodium alginate and $CaHPO_4$ can release drugs in a controlled fashion from hydrogel with gelling and swelling due to their interaction as water penetrates the matrices of the tablet. The purpose of this study was to evaluate release characteristics of the matrix tablet varying the amount of sodium alginate, $CaHPO_4$ and other excipients such as chitosan, hydroxypropyl methylcellulose (HPMC) and $Eudragit^{\circledR}$ RS100 in the simulated gastric and intestinal fluid. The practically soluble ibuprofen was used as a model drug. The release profiles of matrix tablet in the gastric fluid as a function of sodium alginate/$CaHPO_4$ ratio was not pronounced because of low solubility of drug and stability of alginate matrices. However, release rate of drug from the matrix tablet in the intestinal fluid was largely changed when sodium alginate/$CaHPO_4$ ratio was increased, suggesting that the ratio of sodium alginate/$CaHPO_4$ was an important factor to control the gelling and swelling of the matrix tablet. The incorporation of other excipients into the matrix tablet also influenced the release rate of drug. The chitosan and HPMC decreased the release rate of drug. No release of drug was occurred when $Eudragit^{\circledR}$ RS100 was added into the tablet. The retarded release of matrix tablet when excipients were added resulted from the hindrance of swelling and gelling of the matrix tablet containing sodium alginate and $CaHPO_4$. The hardness and bulk density of the matrix tablet was not correlated with release rate of drug in the study. From these findings, the ratio of sodium alginate and $CaHPO_4$ in the matrix tablet in addition to incorporation of excipients could be very important to control the release rate of drug in dosage form design.

• Korean Journal of Food Science and Technology
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• v.17 no.5
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• pp.319-325
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• 1985

Agar was prepared from domestic agarophyte (Gelidium amansii) by a process of acid extraction. Optimal conditions in the acid treatment of the seaweed and the gelling properties of the agar thus prepared were investigated. The yield and gel strength of the control (the agar extracted with distilled water) showed 13,3% and 306g/$cm^2$, respectively. The yield of 38.7% was obtained when agar was extracted with 0.007N Hydorchloric acid while the gel strength of agar,511g/$cm^2$ was observed with the agar extracted with 0.005N Hydorchloric acid solution. The agar extracted with hydrochloric acid solution showed excellent properties of agar at the acid concentration range 0.005N-0.01N The cooking time of 60 min. was found to be effective to the yield and also to the gelling property of the agar and the cooking longer than 60 min. was proved to be destructive to agar. In general, yield and gelling properties of the agar obtained showed a close relation to the acid concentration and cooking time, but no consistent influence on the contents of ash and sulfur trioxide.