• Biotechnology and Bioprocess Engineering:BBE
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• v.6 no.1
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• pp.18-24
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• 2001

The advantage of using Streptomyces griseus HUT 6037 in the production of chitinase or chitosanase is that the organism is capable of hydrolyzing amorphous or crystalline chitin and chitosan according to the type of the substrate used. We investigated the effects of the enzyme induction time and chitin sources, CM-chitosan and deacetylated chitosan (degree of deacetylation 75-99%), on production of chitosanase. We found that this strain accumulated chitosanase when cells were grown in the culture medium containing chitosanaceous substrates instead of chitinaceous substrates. The highest chitosanase activity was obtained at 4 dyas of cultivation with 99% deacetylated chitosan. The specific activities of chitinase and chitosanase were 0.91 and 1.33 U/mg protein at 3 and 5 days, respectively. From the study of the enzymatic digestibility of various degrees of deacetylated chitosan, it was found that (GlcN)$_3$, (GlcN)$_4$and (GlcN)(sub)5 were produced during the enzymatic hydrolysis reaction. The results of this study suggested that the sugar composition of (GlcN)$_3$was homogeneous and those of (GlcN)$_4$and (GlcN)(sub)5 were heterogeneous.

• Korean journal of food and cookery science
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• v.7 no.4
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• pp.93-101
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• 1991

The object of this study was to investigate characteristics of kiwifruit protesae and effect of this enzyme on the functionality of casein. The specific activity of crudely prepared kiwifruit pretense on casein was 196.95 units/mg protein, it showed optimum activity at pH 3.0, $60^{\circ}C$. The degree of hydrolysis of casein with pretense treatment steeply increased to 73.5% and 78.9% for 10 and 20 minutes and then reached 84.1% and 89.3% for 1 and 4 hours, respectively. Solubility of non heated control group was 0.2% at pH 4, while the sample groups treated with enzyme for 0, 10 and 20 minutes were 14.5%, 19.2% and 24.0%, respectively. Casein treated with pretense showed marked increase in foam expansion near isoelectric point. However, enzymatically treated groups had lower foam expansion than the control groups. Foam stabilities of enzymatically modified group were lower than those of the control groups at all pH. Emulsifying activity of the non-heated control group was 0% at pH 4, while the groups modified enzymatically for 0, 10, and 60 minutes showed 51.0%, 55.5% and 54.5%, respectively.

• Korean Journal of Food Science and Technology
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• v.27 no.5
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• pp.729-735
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• 1995

Quality changes of starch syrups were investigated during storage at 20 and $60^{\circ}C$. Color properties such as spectrophotometric properties, HMF and Hunter color value were continuously increased during storage period. And they were largely changed as much as storage temperature and hydrolysis degree were higher. Starch syrups were all showed to flow behaviors as non-Newtonian fluids and increased slightly during storage. And monosaccharide was decreased and di- and oligosaccharide were slightly increased during storage.

• Korean Journal of Food Science and Technology
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• v.27 no.5
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• pp.794-798
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• 1995

Deamidation by neutrase on glutaminyl and asparaginyl residues of protein was examined. The optimum pH and temperature for BSA(bovine serum albumin) deamidation by neutrase were 10 and $20^{\circ}C$, respectively. The incubation for 3 hrs under the optimum condition removed 24% of amide groups and hydrolyzed 2.9% of peptide bonds. Deamidation by neutrase was superior to that by pronase, bromelain, or ficin. Deamidation degrees of egg albumin, soy protein isolate and casein by neutrase under the optimum condition were about 20%, 14% and 14%, respectively. However, relatively high degree of peptide hydrolysis was accompanied with casein deamidation.

• Journal of the Korean Ceramic Society
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• v.45 no.11
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• pp.744-749
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• 2008

The properties of the polymer-modified mortars are influenced by the polymer film, cement hydrates and the combined structure between the organic and inorganic phases. Also, this quality of polymer modified cement strongly depend on weather condition and polymer cement ratio. To overcome this problem, polymer-modified cement were prepared by varying polymer/cement mass ratio (P/C) with $0{\sim}20%$ and constant water/cement mass ratio of 0.5. The effect of polymer on the hydration of this polymer cement is studied on different polymer cement ratio. The results showed that the polymer cement paste have increased the viscosity in addition the amount of polymer dosage and the polymers is completed resulting in a reduced degree of hydration caused by different ion elution amount. Also we know that the reactants is calcium acetate as a results of chemical reaction between acetate group in EVA which is hydrolysis in water and $Ca^{2+}$ ion during hydration of cement.

• Journal of the Korean Ceramic Society
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• v.32 no.9
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• pp.1047-1055
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• 1995

Mn-Zn ferrite granules were formed by a spray-drying method of the slurry containing different kinds and concentrations of binders at various temperatures. The slurry was made by conventional ceramic processing method, that is, by mixing Fe2O3, MnO, ZnO powders (52 : 24 : 24 mol%), calcining and milling. Typical shape of the spray dried granules was spherical. The compaction behavior of these granules was dependent on the spray-drying temperature and the kind and concentration of binders. At lower pressure the granules were displaced and at higher pressure the granules were deformed and fractured to fill pores among the granules. The optimum concentration of the binder was 0.5wt%. The granules containing 0.5wt% PVA 205 were deformed and fractured well and the green density was higher than others. At higher concentrations of the binder the granules were deformed rather than fractured, therefore the green density was lowered because of the remaining unfilled pores. The decomposition temperature and the heat released were increased with increasing the concentration of the binders. The compaction response of the granules containing PVA 205 was more efficient than those containing PVA 217 and PVA 117. Green density was not dependent on the degree of hydrolysis of the binders. The compaction response of the granules spray-dried at 15$0^{\circ}C$ was most efficient.

• Applied Biological Chemistry
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• v.35 no.5
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• pp.389-394
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• 1992

Effect of dry-heat treatment $(130{\sim}220^{\circ}C)$ on properties of corn starch was investigated. No significant changes of surface color and swelling power were observed. Blue value, water-binding capacity, solubility and degree of hydrolysis by acid or glucoamylase were increased; however, intrinsic viscosity and crystallinity were decreased as heating temperature was raised. Noticeable changes occurred between $170{\sim}190^{\circ}C$.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.06a
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• pp.234-235
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• 2007

Transparent nanosized $TiO_2$ sol has been made by sol-gel method, using Titanium(IV) isopropoxide precursor. To promote hydrolysis for titania is needed excess water, Oil bath and temperature about $80^{\circ}C$. $TiO_2$ sol is peptized ranging from pH 1 to 1.5 using hydrochloric acid for the stability of sol during a condensation reaction. The average particle size of $TiO_2$ sol was approximately 20nm. $TiO_2$-sillane sol was synthesized by surface treatment using MTMS to the $TiO_2$ sol. TEM analysis has been used to check the degree of dispersion and FT-IR analysis has been used to see if the sillane has been chemically bonded on the surface of $TiO_2$.

• Journal of the Korean Society of Food Science and Nutrition
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• v.26 no.6
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• pp.1147-1151
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• 1997

To develop an onion sauce, reaction conditions of celluclast 1.5L and pectinex on onion were investigated and organoleptic evaluations were carried out. Degree of hydrolysis(D.H) of hydrolysate by a mixture of celluclast 1.5L and pectinex was a higher than that by each enzyme. Hydrolysate by a mixture of celluclast 1.5L and pectinex(1:3v/v) showed 86% of D.H. and total sugar content of the hydrolysate was 54mg/ml. Hydrolysates showed 83~86% of D.H. at reaction temperature of $25^{\circ}C$ to 45$^{\circ}C$. Total sugar content of the hydrolysate was increased with increasing temperature. D.H. and total sugar content of hydrolysate was 76~86% and 51~63mg/ml, respectively, under acidic conditions. D.H. and total sugar content of hydrolysate were also increased with increasing time. Bitterness, sweetness and ordor of roasted pork prepared by adding onion and onion hydrolysate were significantly different(p<0.05), but color and preference between two groups were not significantly different(p<0.05) between two groups. There was no significant difference(p<0.05) in sweetness and bitterness of the roasted pork prepared by adding different amounts of onion hydrolysate, although ordor and preference of the roasted pork were significantly different(p<0.05).

• Textile Coloration and Finishing
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• v.34 no.3
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• pp.197-206
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• 2022

The purpose of this study was to confirm the optimal spinning conditions for PLA (Polylactic acid) as a fiber forming polymer. According to the melt spinning test results of PLA, the optimal spinning temperature was 258℃. However, it needs to note that relatively high pack pressure was required for spinning at 258℃. At an elevated temperature, 262℃, mono filament was broken easily due to hydrolysis of PLA at a higher temperature. In case of fiber strength, it was confirmed that the draw ratios of 2.7 to 3.3 were optimal for maximum strength of melt spun PLA. Above the draw ratio, 3.3, the strength of the PLA fibers was lowered. It was presumed that cleavage of the PLA polymer chain over maximum elongation. The heat setting temperature of GR (Godet roller) showed that the maximum strength of the PLA fibers was revealed around 100℃. The degree of crystallinity and the strength of the PLA fibers were decreased above 100℃. The optimal take-up speed (Spinning speed) was around 4,000m/min. Thermal analysis of PLA showed 170℃ and 57℃ as Tm (melting temperature) and Tg (glass transition temperature), respectively.