• Archives of Pharmacal Research
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• v.19 no.4
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• pp.280-285
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• 1996

The sustained release dosage form which delivers melatonin (MT) in a circadian fashion over 8 h is of clinical value for those who have disordered circadian rhythms because of its short halflife. The purpose of this study was to evaluate the gelling properties and release characteristics of alginate beads varying multivalent cationic species $(Al^{+++}, \; Ba^{++}, \; Ca^{++}, \; Mg^{++}, \; Fe^{+++}, \; Zn^{++})$. The surface morphologies of Ca- and Ba-alginate beads were also studied using scanning electron microscope (SEM). MT, an indole amide pineal hormone was used as a model drug. The $Ca^{++}, \; Ba^{++}, \; Zn^{++}, \; Al^{++}\; and\; Fe^{+++}\; ions\; except\; Mg^{++}$ induced gelling of sodium alginate. The strength of multivalent cationic alginate beads was as follows: $Al^{+++}\llFe^{+++} the induced hydrogel beads were very fragile and less spherical. Fe-alginate beads were also fragile but stronger compared to Al-alginate beads. Ba-alginate beads had a similar gelling strength but was less spherical when compared to Ca-alginate beads. Zn-alginate beads were weaker than Ca- and Ba-alginate beads. Very crude and rough crystals of Ba- and Ca-alginate beads at higher magnifications were observed. However, the type and shape of rough crystals of Ba- and Ca-alginate beads were quite different. No significant differences in release profiles from MT-loaded multivalent cationic alginate beads were observed in the gastric fluid. Most drugs were continuously released upto 80% for 5 h, mainly governed by the passive diffusion without swelling and disintegrating the alginate beads. In the intestinal fluid, there was a significant difference iq the release profiles of MT-loaded multivalent cationic alginate beads. The release rate of Ca-alginate beads was faster when compared to other multivalent cationic alginate beads and was completed for 3 h. Ba-alginate beads had a very long lag time (7 h) and then rapidly released thereafter. MT was continuously released from Feand Zn-alginate beads with initial burstout release. It is assumed that the different release rofiles of multivalent cationic alginate beads resulted from forces of swelling and disintegration of alginate beads in addition to passive diffusion, depending on types of multivalent ions, gelling strength and drug solubility. It was estimated that 0.2M $CaCl_2$ concentration was optimal in terms of trapping efficiency of MT and gelling strength of Ca-alginate beads. In the gastric fluid, Ca-alginate beads gelled at 0.2 M $CaCl_2$ concentration had higher bead strength, resulting in the most retarded release when compared to other concentrations. In the intestinal fluid, the decreased release of Ca-alginate beads prepared at 0.2 M $CaCl_2$ concentration was also observed. However, release profiles of Ca-alginate beads were quite similar regardless of $CaCl_2$ concentration. Either too low or high $CaCl_2$ concentrations may not be useful for gelling and curing of alginate beads. Optimal $CaCl_2$ concentrations must be decided in terms of trapping efficiency and release and profiles of drug followed by curing time and gelling strength of alginate beads.

• Korean Journal of Food Science and Technology
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• v.27 no.3
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• pp.336-341
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• 1995

Effect on alginate, pectin and Ca salts on textural properties of whole soybean gel(soygel) was investigated. The soygel was prepared by addition of sodium alginate, pectin and Ca salts into whole soy flour(300 mesh, WSF) suspension followed by through mixing. Addition of sodium alginate or pectin into WSF suspension significantly increased the hardness, adhesiveness and cohesiveness of the gel. The most uniform gel was obtained by $12{\sim}15%$ addition of sodium alginate or pectin, while their mixture rather decreased the textural properties. Sensory evaluation by ranking test for the gels showed that 12% sodium alginate and 0.125g $CaSO_4/g$ WSF produced the most desirable gel in terms of elasticity, uniformity, smoothness and total acceptability, followed by 12% sodium alginate and 0.12g Ca $gluconate-CaSO_4$(50 : 50). From the results, the optimal preparative conditions for soygel were suspension of WSF in 10 times of water(v/w), addition of 12% sodium alginate(w/w of WSF) and 12.5% $CaSO_4$ or Ca $gluconate-CaSO_4$(50 : 50) into WSF suspension followed by gel formation at $4^{\circ}C$.

• Food Engineering Progress
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• v.14 no.3
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• pp.208-216
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• 2010

Lab scale experiments were conducted in order to assess the applicability of $CaCO_{3}$-alginate beads as neutralizer for the high cell density cultivation and prepare the direct vat inoculation cultures of isolated sourdough lactic acid bacteria. With increasing the amount of bead and decreasing the diameter of bead in acidic solution, the neutralizing effect of $CaCO_{3}$-alginate bead became higher. In batch process with $CaCO_{3}$-alginate beads, Lactobacillus amylovorus DU-21 isolated from sourdough showed the highest viable cell counts and optical density in MRS broth. The values of viable cell counts and optical density were 9.996 log CFU/mL and 3.97, respectively. Experiments on the conditions which increase viability during lyophilization were carried out and the following results were obtained; 15% glycerol revealed the high cryoprotective effect on the concentrated cultures during lyophilization among the two cryoprotective agents. Consequently, $CaCO_{3}$-alginate beads and 15% glycerol were found to be useful not only to cultivate Lactobacillus amylovorus DU-21 but also to preserve strain.

• The Korean Journal of Food And Nutrition
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• v.15 no.2
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• pp.89-96
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• 2002

The adsorption characteristics of sodium chloride into Ca-alginate beads have been investigated and the result were as follows: Sodium chloride uptake by Ca-alginate beads increased with time. The highest uptake volume of sodium chloride was 4.2g after 10 minutes. The uptake volume by Fe, Ca, Ba, and Sr-alginate beads was 5.6g, 4.2g, 4.2g and 4.0g, respectively but in case of Fe-alginate beads, the induced hydrogel beads were very fragile and the strength of Fe-alginate beads were weaker than Ca- and Ba-alginate beads. Mg-alginate bead was not formed and Ca-, Ba- and Sr-alginate beads had a similar uptake volume about 4.2g, respectively. The uptake volume of sodium chloride by CaCl$_2$concentration(0.1M. 0.2M and 1M), curing solution, was 4.8, 4.2g and 4.1g, respectively. The uptake volume by sodium alginate concentration(0.6%, 1% and 2%) was 2.8g, 4.0g, and 4.4g, respectively and Ca-alginate bead size was not effected in uptake sodium chloride. The uptake rate on initial sodium chloride concentration(4%, 8%, 12% and 16%) was 30%, 28%, 27% and 25%, respectively. The uptake rate on basic pH(10.0) was higher than when compared to other neutral pH(6.8) and acidic pH(4.0). The initial uptake velocity of sodium chloride from immobilization beads with salt resistant bacteria was lower than that of non-immobilization beads. The uptake rate of sodium chloride was decreased according to elongation of curing time. Reusability of Ca-alginate beads was possible but according to reutilization, the salt uptake volume of beads was also decreased. The uptake volume of sodium chloride from Doengjang by Ca-alginate beads on time course(3, 6, 12, and 24 hour) was revealed 5g, 6g, 7g and 7g, respectively.

• Textile Coloration and Finishing
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• v.23 no.1
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• pp.51-59
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• 2011

Calcium alginate fiber were prepared by wet spinning of various conditions, including different concentrations of sodium alginate solution and $CaCl_2$ concentrations for coagulating the fiber through an absorption of calcium ion. The absorption of calcium ion during the coagulating step lead to solidify the fibers by the replacement of sodium ion with calcium ion to produce some crosslinking. The concentration of calcium ion in the calcium alginate fiber seems to be well related to the mechanical and physical property of the fiber, such as fiber strength moisture regain, and degree of swelling. The tensile strength of calcium alginate fiber was increased along with the increasing amount of sodium alginate solution. According to EDS analysis, 7 wt% $CaCl_2$ coagulation bath resulted in more calcium ion in the fiber compared to 3 wt% $CaCl_2$ coagulation bath. The decomposition temperature of calcium alginate fiber was $199^{\circ}C$, which $14^{\circ}C$ higher than that of sodium alginate.

• Polymer(Korea)
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• v.38 no.5
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• pp.580-587
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• 2014

Composite films of zinc calcium alginate were prepared by a film maker from 7 wt% sodium alginate solution and then they solidified into 3, 5 wt% content $ZnCl_2$, $CaCl_2$ solution followed by washing and drying at room temperature. The characteristics were measured with several methods (antimicrobial activity, water solubility, swelling ratio and viscosity, SEM, EDS) and the film properties were investigated. Composite films of zinc calcium alginate showed an increase in the water resistance by increasing $ZnCl_2$ and $CaCl_2$ content and the antimicrobial test showed that the calcium alginate as well as zinc alginate films result in excellent antimicrobial activity in the two strains, Staphylococcus and Escherichia coli. The results show the possible improvement of the physical properties of composite films.

• Microbiology and Biotechnology Letters
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• v.21 no.4
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• pp.373-380
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• 1993

When the cells of yeast K35 were immobilized in Ca-alginate gel, cell concentration and viability decreased as alginate concentration increased. Considering the results, 2% (w/v) Ca-alginate concentration would be suitable. Among various concentrations of additives and cross-lin-king agent, the addition of 1.67% (w/v) of bentonite together with 0.33% (v/v) of glutaraldehyde (ABG bead) resulted in the highest ethanol production of 1.8%(w/v), using YPD medium containing 2% glucose. ABG bead seemed to be more resistant to phosphate ion than Ca-alginate bead. 0.33%(w/v) of phosphate was a proper concentration for the ethanol production by ABG bead. Scanning electron microscopic observation depicted that the immobilized cells on the bead surface were coated by alginate gel and that the cells in the internal bead were cross-linked with alginate matrix. When repeated-batch culture was performed with ABG bead for 40 days in a packed-bed reactor, ethanol concentration of about 90~110 g/l-gel was maintained. Cell viability was maintained around 70%, and outgrowing cell concentration was below 6.3% of total cell concentration. Consequently, the results showed that ABG head was a potential carrier for continuous production of ethanol compared to conventional Ca-alginate bead.

• Journal of the Korean Professional Engineers Association
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• v.21 no.2
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• pp.13-18
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• 1988

A Study for ethanol fermentation with immobilized yeast that is entrapped to Ca-alginate beads and batch system was carried out using molasses as substrate. The results are as follows. 1. The yield of alcohol fermentation is more efficacious then that of conventional fermentation process. The beads were used 15times and got a result of fermentation yield rate 89. 57％∼92.35％f, which is comparable with the rate of 86.3％ gained from the conventional fermentation process. 2. The concentration of Ca-alginate was 1∼5％ For long run use (2520 hours) it is necessary 2％ or more concentration of Ca-alginate. 3. The amount of the yeast cells for entrap to Ca-alginate beads was required 1.0g (indried material) or more for 200g Ca-alginate beads.

• Applied Biological Chemistry
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• v.24 no.2
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• pp.149-152
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• 1981

The immobilization of Lactobacillus bulgaricus was investigated by various method, e.g. by use of polyacrylamide gel and Al-, Ca-, Fe- or Mg-alginate beads, and the most active immobilized cells were obtained by entrapment in a Ca-alginate beads. These immobilized microbial cells, when introduced into 4.5% lactose solution and whey solution showed maximum relative activity of 28% or lactose solution and 18% for whey solution as measured against the native microbial reference standard (100).

• Journal of the Korean Society of Industry Convergence
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• v.24 no.5
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• pp.563-571
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• 2021

In this study, calcium alginate based cation exchange membrane was prepared and used to develop membrane capacitive deionization (MCDI) system for effective hardness control. As a major result, the MCDI with Ca-alginate membrane showed 27% better deionization capacity than the MCDI with a commercial cation exchange membrane. This superior improvement in the deionization capacity was expected to be due to the high ratio of transport number/electrical resistance (S_c/R_ratio) of Ca-alginate membrane. In addition, the MCDI with Ca-alginate membrane showed better deionization performance than the MCDI with Ca-alginate coating. This was because the space between the electrode and the Ca-alginate membrane was utilized for ion adsorption. The preliminary results indicated that the MCDI with Ca-alginate membrane can be a viable technique for the hardness control.