• 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.

• Journal of the Korean Society of Radiology
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• v.17 no.6
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• pp.985-991
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• 2023

A tissue-equivalent phantom is necessary for quality control of hyperthermia therapy. However, since there is no phantom for this purpose, phantoms made from agar are being used in various studies. The tissue-equivalent properties of the agar phantom were confirmed by comparison with the tissue-equivalent material bolus in this study. CT images of the agar phantom and bolus were acquired, and tissue equivalent characteristics were analyzed with image analysis and dose calculation using a computerized radiation therapy planning system. The average pixel value was 96.960±10.999 in bolus, 108.559±8.233 in 3% agar phantom, and 111.844±8.651 in 4% agar phantom. Using the SSD technique, 100 cGy was prescribed at a depth of 1.5 cm and 6 MV X -ray was set to irradiated to 10x10 cm2, and the absorbed dose according to depth was calculated from the central axis of the beam. The intraclass correlation coefficient of dose distribution of bolus, 3% agar phantom, and 4% agar phantom was 0.979 (p<.001, 95%CI .957-.991). The density (g/cm3) at the point where the absorbed dose was calculated was 0.990±0.020 at the bolus, 1.018±0.020 at the 3% agar phantom, and 1.035±0.024 at the 4% agar phantom. In this study, the internal density distribution and uniformity of the agar phantom were confirmed to be appropriate as a tissue equivalent material by analysis of CT images and a computerized radiation therapy planning system.

• Korean Journal of Veterinary Research
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• v.10 no.2
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• pp.1-5
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• 1970

In these studies the efficracy of plate, tube agglutination and agar-gel precipitin test were compared for the detection of pullorum infected chickens. From all the chickens showing positive reaction in agar-gel precipitin test, Salmonella pullorum organisms were isolated.

• KSBB Journal
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• v.13 no.4
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• pp.378-382
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• 1998

Agar hydorlysates or agarooligosaccharides from agar prepared by Cytophaga agarase showed eight spots on TLC plate and the degree of polymerization of the spots were in the reange of 2.5 - 6.5. Each component of the hydrolysate as tested the several functionalities such as antimicrobial activity, anticavity activity, and anticoagulant activity. The anticativity activity and anticoagulant acitvity were found in all fractions of hydrolysates and several spot on TLC, whereas the anticoagulant activity was very low.

• Journal of Food Hygiene and Safety
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• v.38 no.3
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• pp.170-175
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• 2023

In this study, the effect of MnSO₄ on the insecticidal crystal (IC) produced by Bacillus thuringiensis for a rapid detection medium was analyzed. The strains used included one B. thuringiensis reference (KCTC 1511) and nine wild-type strains. The IC in B. thuringiensis was detected following the method published by the Ministry of Food and Drug Safety in Korea. In the nutrient agar to which 0.005% MnSO₄ was added, IC was observed on two of the three plates after 48 hours of incubation and on all three plates after 120 hours. In AK agar, IC was observed on one and two of the three plates after 48 and 96 hours of incubation, respectively. These results indicated that 0.005% MnSO₄ nutrient agar is more appropriate than AK agar for production of IC in B. thuringiensis. The effect of various MnSO₄ concentrations on IC production was studied after 24 hours of incubation. IC was produced on 1 of the 10 plates with 0.000% MnSO₄ nutrient agar, 2 of the 10 plates with 0.001% MnSO₄ nutrient agar, and 3 of the 10 plates with 0.002% MnSO₄ nutrient agar. IC was not observed for the other nutrient agars containing 0.003%-0.009% MnSO₄. These results indicated that nutrient agar with 0.002% MnSO₄ led to the most rapid production of IC by B. thuringiensis after 24 hours of incubation. However, the conditions for IC production by B. thuringiensis depended on the incubation conditions and strain activity. Therefore, further studies are needed to verify the effects of 0.002% MnSO₄ on the production of IC by various Bacillus thuringiensis strains.

• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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• v.25 no.3
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• pp.69-77
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• 2019

Agar-based nanocomposite films were prepared by incorporation of zinc oxide nanoparticles (ZnONP) and grapefruit seed extract (GSE). The composite films were characterized using FT-IR, UV-visible spectroscopy and thermalgravimetric analysis (TGA). The composite films showed light absorption peaks at 220 and 380 nm, characteristic for GSE and ZnONP, respectively. The UV-light transmittance of the agar film was markedly reduced from 54.4 ± 1.3% to 5.8 ± 2.5% with little sacrifice of transparency when 3 wt% ZnONP and 5 wt% GSE were added. The mechanical and water vapor barrier properties increased slightly though they were not significant statistically by the addition of ZnONP and GSE. The nanocomposite films showed stronger antibacterial activity against L. monocytogenes than E. coli O157: H7 and the antibacterial activity was affected by bacterial types as well as concentrations of ZnONP and GSE. The nano-composite film incorporated with 3 wt% of ZnONP and 5 wt% of GSE exhibited strong antibacterial activity against Listeria monocytogenes and E. coli O157: H7. The results indicate that 3 wt% of ZnONP and 5 wt% of GSE are the optimal concentrations for producing functional agar/ZnONP/GSE composite films.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.29 no.5
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• pp.722-726
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• 1996

To bring out the functional properties of Agar-agar extracted with 0.01N $H_2SO_4$ from Cellidium amansii produced in Che-ju Udo and its rheological properties were investigated. The flow behavior indexes in the range of $0.5\~5\%$ agar-agar solution were $0.62\~0.69\;at\;80^{\circ}C,\;0.46\~0.67\;at\;60^{\circ}C\;and\;0.34\~0.64\;at\;50^{\circ}C$. The consistency indexes were $0.12\~1.26\;Pa{\cdot}s^n\;at\;80^{\circ}C,\;0.12\~7.28\;Pa{\cdot}s^n\;at\;60^{\circ}C\;and\;3.9\~19952.6\;Pa{\cdot}s^n\;at\;50^{\circ}C$. Consistenry index's existence nature to concentration is two straight line relation which have different slopes on the border of $2\%$ concentration of agar-agar solution and existence nature of temperature followed Arrhenius equation. And the activation energy, in the range of $0.5\%\~5\%$ agar-agar solution, were $0.09\~13.51\;kcal/g{\cdot}mol$.

• Korean journal of applied entomology
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• v.48 no.2
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• pp.269-274
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• 2009

Rearing media were selected for the production of sterile larvae of greenbottle blowfly, Phaenicia (=Lucilia) sericata (Meigen) which is widely used in maggot therapy. Eight media available in the market were used in this study. Egg hatchability was not different among the media. Survivorship of the larvae was higher in blood agar (BA), sabouraud dextrose agar, and brucella blood agar than the others. A higher content (20${\sim}$40%) of sheep blood in BA and chocolate agar increased the survivorship of larvae. The eggs and the early 3rd larvae could be stored for 12 days at $8^{\circ}C$ and for 15 days at $6^{\circ}C$ without decrease in hatchability and larval survivorship, respectively.

• Plant Biotechnology Reports
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• v.5 no.4
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• pp.345-352
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• 2011

The rheological and diffusion properties of blends of agar/guar gum, agar/Phytagel and Phytagel/guar gum were analysed and compared to those properties of agar or Phytagel applied alone at two different gelling concentrations. Moreover, their effects on the shoot multiplication of the apple scion Galaxy and two black locust clones (SF63, SF82) were studied, and their cost benefits over agar were calculated. Elastic hydrogel formation was demonstrated for each blend by rheological measurements, but the gel strength depended on the types and concentrations of the applied gelling agents and blends. Guar gum was able to speed the diffusion in the different blends, and diffusion was independent of gel strength. The rate of shoot multiplication increased (to 8.9 shoots per explant) and the percent of hyperhydrated shoots decreased (to 12%) when the blend of agar/guar gum was used for the shoot multiplication of apple. Similarly, the highest multiplication rates of black locust clones (between 3.9 and 4.1) were obtained on media solidified by blends containing guar gum. The best shoot performance with the lowest percent of hyperhydrated shoots (11-12% in SF63 and 2-23% in SF82) was achieved using agar alone or the agar/guar gum blend. The shoot multiplication was improved of both species and the production cost was reduced by 42% by using the agar/guar gum blend.

• The Korean Journal of Mycology
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• v.9 no.4
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• pp.193-197
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• 1981

Nematode destroying-fungi from ginseng field were isolated and then identified on 2% wateragar and malt extract agar media. 1. Six strains of Arthrobotrys sp. and three strains of Harposporium sp. were isolated and identified. 2. Arthrobotrys sp. formed trapping apparatus when they were cultured with Nematode and appeared to be destroying fungi. 3. Harposporium sp. appeared to be endoparasitic fungi. 4. Both Arthrobotrys sp. and Harposporium sp. were grown well on nutrient agar and malt extract agar.