• Journal of Life Science
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• 제11권1호
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• pp.14-21
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• 2001

To investigate the changes of carbohydrate metabolism in the senescing leaves of Zea mays during dark-induced senescence, the changes in the contents of reducing sugar, sucrose and starch as well as the activities of sucrose synthase, three isozymes of invertase, and ${\alpha}$-amylase were measured. In the senescing leaves, the content of reducing sugars temporarily increased at 4 d and rapidly decreased thereafter, whereas sucrose contents gradually decreased thereafter, whereas sucrose contents gradually decreased until 3 d of senscence and significantly decreased thereafter. The activities of intracellular invertases such as soluble acid and alkaline formed gradually enhanced until 4 d of leaf senescence and significantly declined thereafter. The extracellular invertase activity showed no significant changes during leaf senescence. The deactivation of sucrose synthase was observed within 3 d of leaf senscence. On the other hand, the starch contents gradually declined during 2 d of leaf senescence, and showed a temporary increase at 3 d, which is similar to the pattern of sucrose synthase activity., These results imply that sucrose in the senescing leaves. The major enzymes which correlated to the breakdown of sucrose during dark-induced senescence were soluble acid and alkaline invertases, not sucrose and ABA accelerated leaf senescence by inducing the accumulation of reducing sugar. These result, therefore, that leaf senescence may be mediated by the temporary quantitative changes of reducing sugar induced by the activation of intracellualr inveertases.

• International Journal of Industrial Entomology and Biomaterials
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• 제13권1호
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• pp.45-50
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• 2006

Papers were prepared from cut cocoons and mulberry branches, which are byproducts from sericulture industry. The long filament of silk should be cut into appropriate length in order to prepare paper and this was achieved by chemical method. By a mixture of sodium hydroxide and sodium carbonate solution, the silk filaments were cut into short fibers (less than 1 mm in length). Since the short silk fibers (sSf) could not bind each other by itself, starch and poly(ethylene oxide)(PEO) were added as a bonding agent. When starch and PEO were used in a ratio of 3:7, the silk papers had optimum mechanical properties for paper. Fibers from the skin of mulberry branches (MBF) were added to sSf to enhance the mechanical properties of pure silk paper. Bleaching of MBF was performed with a mixture of hydrogen peroxide and sodium silicate. The mechanical properties were greatly enhanced and the optimum blend ratio of MBF and sSf were 7:3. The mulberry/silk paper has good absorption property against formaldehyde, and therefore, the paper could be applied as a wall paper for preventing the sick house syndrome.

• Journal of Microbiology and Biotechnology
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• 제1권1호
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• pp.54-62
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• 1991

Cyclodextrin glucanotransferase(CGTase) derived from Bacillus macerans was immobilized by (1) covalent linkage on chitosan and chitin with glutaraldehyde, (2) adsorption on DEAE-cellulose and Amberite IRA 900 after succinylation, and (3) entrapment on alginate and polyacrylamide by cross linking. Adsorption on Amberite IRA 900 and covalent linking on chitosan were identified to be the most suitable immobilization methods considering the yield of activity and stability of immobilized CGTase. The enzymatic properties of immobilized CGTase were investigated and compared with those of the soluble CGTase. Thermal stability of CGTase immobilized on chitosan was increased from 50 to $55^{\circ}C$, and the optimum temperature of CGTase immobilized on Amberite IRA 900 was shifted from 55 to $50^{\circ}C$. The effect of molecular size of soluble starch (substrate) on immobilized CGTase investigated using partially liquefied substrates with different dextrose equivalent(DE). Cyclodextrin(CD) conversion yield augmented according to the increase of DE level for immobilized CGTase on Amberite IRA 900. CD conversion yield of partially cyclized starch with soluble CGTase was higher compared with liquefied one with ${\alpha}-amylase$.

• 한국미생물·생명공학회지
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• 제30권4호
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• pp.293-297
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• 2002

효모 S. cerevisiae에서 B. stearothermophilus 유래의 CGTase를 발현 생산하였으며, 분비, 생산된 단백질을 정제하여 그 특성을 조사하였다. 재조합 효모 S. cerevisiae 2805/pVT- CGTS가 생산하는 CGTase의 분자량은 효모에서 발현될 때 고당쇄가 부가되어 야생형의 68kDa에 비해 15-160% 증가된 약 78-178 kDa으로 나타났다. 효모 S. cerevisiae에서 발현된 CGTase의 효소반응 최적활성조건은 pH7.0, $65^{\circ}C$였고, 열안정성에 있어서 $75^{\circ}C$에서 약 90%의 잔존활성을 가질 정도로 내열성이 개선되었다. 효모 S. cerevisiae에서 발현된 CGTase는 5% soluble starch를 기질로 약 40.2%의 CD 전환율 및 3 : 6 : 1의 $\alpha$-, $\beta$-, ${\gamma}$-CD의 생산 비율을 나타내어 야생형과 별다른 변화가 없었다.

• 한국식품영양학회지
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• 제31권1호
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• pp.80-88
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• 2018

This study was conducted to develop easily chewable Korean rice cake (Garaedduk) for the elderly while maintaining its original form and flavor. We developed two types of easy-to-chew Garaedduk products by adding starch-degrading enzyme or trehalose, respectively. Characteristics of Garaedduk products were investigated and comparative analysis was carried out between control and experimental groups. The water content of control and enzyme-added Garaedduk was 43.55% and 44.11%, respectively, which was significantly higher than trehalose-added Garaedduk (40.30%) as free water content was reduced by the formation of hydrogen bonds between trehalose and water molecules. Due to the browning of reducing sugar produced by the decomposition of rice starch, Hunter b-value of enzyme-added Garaedduk was significantly higher compared to others. Hardness, adhesiveness, gumminess, and chewiness of experimental groups were lower than the control group. Consumer test scores showed significant differences with respect to overall liking, chewiness, and swallowing between control and experimental groups. Elderly preferred experimental Garaedduks over control and the experimental groups were evaluated to be softer, easily chewable, and swallowable.

• KSBB Journal
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• 제18권6호
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• pp.479-484
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• 2003

염색폐수에 포함된 PVA를 생물학적으로 제거하고자 34 종의 PVA 분해용 균주를 염색폐수 및 슬러지로부터 분리하였다. 이 중 PVA 분해 시험을 거쳐 2 종의 균주를 최종분리하여 동정하여 Microbacterium barkeri LCa와 Paenibacillus amylolyticus LCb로 명명하였다. 최종분리균의 최적성장조건 및 최대분해조건을 규명해보았는데, 온도는 3$0^{\circ}C$, pH는 7, 탄소원은 starch, 그리고 질소원은 peptone으로 판명되었으며, 최적조건 하에서의 PVA 분해율은 89%를 보였다. 또한, 본 연구에서 분리한 균주는 PVA 중합도의 영향 없이 높은 분해율을 유지하는 것으로 판명되었다.

• Mycobiology
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• 제39권4호
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• pp.278-282
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• 2011

The objective of this study was to find useful fungi with ${\alpha}$-amylase activity from the Korean traditional nuruk for the quality of traditional Korean alcoholic beverage. In this study, 165 samples of traditional nuruk were collected from 170 regions throughout Korea and the fungi were isolated to a total of 384 strains. In order to investigate the effect of microflora on nuruk, ${\alpha}$-amylase activity, saccharogenic power (SP), starch hydrolysis activity and acid producing activity were evaluated. Ten strains were selected by ${\alpha}$-amylase activity, which ranged from 458.47 to 1,202.75 U/g. The size of the discolored zone for the starch hydrolysis activity of each fungus ranged from 0.3 to 2 cm. The SP of the 10 strains ranged from 228.8 to 433.4 SP. Of the 10 stains, three were identified as Aspergillus oryzae, two as Aspergillus flavus, two as Lichtheimia sp., one as Rhizopus oryzae and two as other strains. The total aflatoxins present in the nuruks were examined using enzyme-linked immunosorbent assay. The 10 nuruks had less than 1.11 ppb of aflatoxins.

• 한국미생물·생명공학회지
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• 제21권1호
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• pp.6-12
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• 1993

토양에서 분리한 294균주 중에서 chitinase 생산성이 우수한 균주를 선택하였으며 형태학적, 생화학적 및 배양학적 실험과 Bergey's Manual of systematic Bacteriology의 색인을 통하여 Streptomyces lydicus로 동정하였다. 효소 생산의 최적 조건을 검토하여 본 결과 배양 후 6일이 경과하였을 때, 배지의 초기 pH는 8, 배양 온도는 $30^{\circ}C$, 배지에 2의 chitin을 첨가하여 배양하였을때 효소가 가장 많이 생산되었다. 또한 soluble starch, dextrin을 탄소원으로 하여 배양하였을 때, ammonium oxalazte, tryptone, casamino acid를 질소원으로 하여 배양하였을 때 효소 생산이 높게 일어났다.

• 약학회지
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• 제59권2호
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• pp.70-76
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• 2015

A Softgel is an oral dosage form for medicine similar to capsules and softgel dosage form offers several advantages over other oral dosage forms, such as delivering a liquid matrix designed to solubilize and improve the oral bioavailability of a poorly soluble compound as a unit dose solid dosage form, delivering low and ultra-low doses of a compound. This study aimed to qualify a proprietary vegetable soft capsule which contains modified starch and carrageenan as capsule shell components compare to the conventional gelatin softgel. Four kinds of samples were prepared with vegetable and gelatin capsule shell, respectively. Morphology of capsule shell, mechanical strength of capsule, and hygroscopic properties were studied for comparing the quality attributes of softgel. Short-term stability against heat and moisture was also investigated in this study. Vegetable capsule shell showed better mechanical strength, physical stability and disintegration time for temperature and humidity than those of conventional gelatin capsule shell with four different filling materials used frequently as soft capsule form. Conclusively, this vegetable capsule shell polymer system can replace easily gelatin-shell systems and additionally allows encapsulation of lipid fills at high temperatures that are semisolid or solid-like at room temperature.

• 한국포장학회지
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• 제29권1호
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• pp.9-14
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• 2023

The application of starch-based films is limited by the poor water vapor barrier and mechanical properties. In this study, plasticized octenyl-succinated corn starch (OTPS) was mixed into Poly (butylene adipate-co-terephthalate) (PBAT) with various concentration (0/0.25/0.5/0.75 wt%) of epoxidized soybean oil (ESO) to enhance the mechanical properties and the hydrophobicity of blends. Tensile Strength and elongation at break of PBAT/OTPS film was slightly strengthened as the added ratio of ESO raised to 0.5 wt%, yet lessened again in 0.75 wt% sample. The yield strength and elastic modulus were highest in 0.25wt% of ESO added. In thermal properties, the melting temperature (T_m) and crystallization temperature (T_c) were highest at ESO 0.25 and the maximum degradation temperature (T_max) of components of the films were developed as ESO added. Also, it has been proved that the addition of hydrophobic substances reduces the hydrophilicity of the film by contact angle. This suggests the use of epoxidized oil for preparing films based on high TPS content allows obtaining enhanced interfacial adhesion. This study confirmed that ESO acts as a compatibilizer between OTPS and PBAT to improve the mechanical properties and hydrophobicity of the sample. The sample containing 0.5wt% of ESO was the most suitable for packaging application.