• Applied Biological Chemistry
• /
• v.37 no.2
• /
• pp.85-93
• /
• 1994

The fish skin gelatin hydrolysates were produced using a continuous two-stage membrane (MWCO 10,000, MWCO 5,000) reactor, and molecular weights, amino acids and functional properties of the hydrolysates were investigated. The major molecular weights distribution of the major fractions were $8{\sim}10\;KDa$ and $4.5{\sim}6.5\;KDa$ in the 1st-step hydrolysates, $2{\sim}6\;KDa$ and $0.5{\sim}2\;KDa$ in the 2nd-step hydrolysates. Among the amino acids in the hydrolysates, glycine, proline, serine, alanine, hydroxyproline, glutamic acid and aspartic acid having sweet taste were responsible for $68{\sim}72%$ of the total amino acids. But valine, methionine, isoleucine, leucine, phenylalanine and histidine having a bitter taste were only $23{\sim}25%$ Taste evaluations show that the gelatin hydrolysates have a brothy and sweet taste, 2nd-step hydrolysate have more a favorable taste than 1st-step hydrolysate. The hydrolysates were completely soluble and clear over the entire pH range. Moisture sorption at intermediate water activities of the 2nd-step hydrolysate was much higher than the unmodified fish skin gelatin, but foaming and emulsification properties were poor. Buffer capacity of the 2nd-step hydrolysate was higher than the fish skin gelatin and 1st-step hydrolysate, while viscosities of the hydrolysates were lower than the fish skin gelatin.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.24 no.5
• /
• pp.345-355
• /
• 1991

In order to effectively utilize the by-products of sea-food, the utilization of enzyme-modified flounder(Limanda aspera) skin gelatin as an emulsifier was investigated. In the experiment, the gelatin was extracted from the flounder skin with the heat-treatment at $60^{\circ}C$ and in pH 5.0 for 3 hrs with four volumes of distilled water and emulsifiers were enzymatically modified L-leucine alkyl esters$(L-leucine-OC_n$ : n= 2, 4, 6, 8 and 10) to the gelatin$(EMFSG-C_2,\;EMFSG-C_4,\;EMFSG-C_6,\;EMFSG-C_8,\;EMFSG-C_{10})$ for improving the functional properties such as emulsifying activity, emulsifying viscosity, whippability, electric conductivity, critical micelle concentration and interface tension, etc. Also, the functional properties of the L-leucine alkyl ester modified gelatins were compared with those of Tween-60 as reference. Molecular weights of the enzymatically modified flounder skin gelatin(EMFSG) were 20.5kDa. in $EMFSG-C_2.\;19.5 kDa.\;in\;EMFSG-C_4\;and\;16.5kDa.\;in\;EMFSG-C_6,\;EMFSG-C_8$ and $EMFSG-C_{10}$. respectively. Emulsifying activity and emulsifying viscosity in the modified gelatins were risen with increase of carbon number of the introduced L-leucine alkyl esters. Among the modified gelatins, $EMFSG-C_6$ exhibited the highest emulsifying stability and foaming stability, whereas $EMFSG-C_8$ showed the highest whippability. The electric conductivities of the all $EMFSG-C_n$ were linearly risen to critical micelle concentration(CMC) , therefore $EMFSG-C_{10}$ exhibited the lowest CMC value and interface tension, and dense particles in the microscopic observation. In conclusion, the best quality in functional properties was assured on $EMFSG-C_{10}$.

• Journal of the East Asian Society of Dietary Life
• /
• v.9 no.4
• /
• pp.435-441
• /
• 1999

This study was designed to investigate the effects of roasting temperatures on the antinutritional factors and functional properties of sesame protein isolates. The protein contents a sesame protein isolates (SPI) prepared at roasting temperatures of 5$0^{\circ}C$, 10$0^{\circ}C$, 15$0^{\circ}C$ and 20$0^{\circ}C$ were 65.5%, 66.6%. 68.9% and 64.1%, respectively. Total phenolic compounds, condensed tannin and phytate contents of SPI was increased from 5$0^{\circ}C$ to 20$0^{\circ}C$. From color measurements, higher roasting temperature decreased 'L' and 'b' values significantly, but 'a' value was increased. The bulk density, fat absorption and water absorption of SPI was increased as the temperature of roasting was increased. Sesame protein isolates prepared by roasting at 5$0^{\circ}C$, 10$0^{\circ}C$ and 15$0^{\circ}C$ had higher emulsifying activity than those prepared by roasting at 20$0^{\circ}C$. Foaming capacity of SPI was not changed by roasting up to 10$0^{\circ}C$, but this property was reduced dramatically when roasted at 20$0^{\circ}C$.

• Journal of Korean Tunnelling and Underground Space Association
• /
• v.23 no.6
• /
• pp.503-516
• /
• 2021

Autonomous fire detection and suppression system requires advanced technology for complex detection technology and injection/control technology for accurate hitting by fire location. Also, foam spraying should be included to respond to oil fires. However, when a single spray monitor is used in common, water and foam spray properties appear different, so for accurate fire suppression, research on the spray trajectory and distance will be required. In this study, experimental studies and numerical analysis studies were combined to analyze the foam spray characteristics through the spray monitor developed for the establishment of an autonomous fire extinguishing system. For flow analysis of foam injection, modeling was performed using OpenFOAM analysis software, and the commonly used foaming agent (Aqueous Film-Forming Foam) was applied for foam properties. The injection distance analysis was performed according to the injection pressure and the injection angle according to the form of the foam, and at the same time, the results were verified and presented through the injection experiment.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.14 no.4
• /
• pp.345-352
• /
• 1985

To characterize the protein from arrowroot leaf, proteins were extracted and separated from arrowroot leaf, then its amino acid composition and functional properties were studied. Protein in arrowroot leaf was consisted of 18.5% albumin, 33.5% globulin, 34.0% glutelin, 6.2% protamine and 7.8% insoluble residues. The rates of precipitation of proteins which extracted with water, 1M NaCl, and 0.015N NaOH as a solvent were 84.7% (at pH 3.0), 76.4% (at pH 2.5) and 86.4% (at pH 4.0), respectively. The extracted proteins were separated up to about 90% by organic solvents such as ethanol and acetone at 80% concentration, Composition of arrowroot leaf protein concentrates were: $1{\sim}2%$ moisture, $59{\sim}67%$ protein, $4{\sim}8%$ ash and $5{\sim}6%$ (dialyzed concentrates) or $1{\sim}2%$ (acetone-treated ones) lipid. Main amino acids of the concentrates were aspartic acid, glutamic acid and glycine. Solubility profile of the concentrates according to pH was typical. The minimum solubility (below pH 5.0) of acetone extracted protein concentrates was lower than that of unextracted ones, whereas the reverse was true for pH value above this region. Bulk density, water and fat absorption of the concentrates were attributable to correlation to the treatment of acetone. And the bulk density of the concentrates was negatively correlative to both water and fat absorption. Emulsifying and foaming properties were not varied with the treatment of acetone.

• Journal of the Korean Recycled Construction Resources Institute
• /
• v.4 no.4
• /
• pp.388-395
• /
• 2016

This paper explores the photocatalytic sensitivity of cement mortar incorporated with recycled $TiO_2$ from waste water sludge. Basically, $TiO_2$ cluster sank down slowly to the bottom of cement mortar specimen before setting and hardening process. This leads the mismatch of $TiO_2$ concentration on the top and the bottom faces of a specimen. This poorly dispersed $TiO_2$-cement mortar naturally exhibits poor NOx removal efficiency especially on the top of cementitious structure. In architectural engineering application such as building or housing structures, one can simply filp over from the bottom so that more $TiO_2$ concentrated surface can be placed outward into the air. However, in highway pavement case, this could not be applicable due to in-situ installation of concrete pavement. Hence, the dispersion of $TiO_2$ cluster inside the cementitous material is getting important issue onto road construction application. To elaborate this issue, according to our results, silica fume, high-ranged water reducer, viscosity agent, blast furnace slag were not enhanced much of dispersion characteristics of $TiO_2$ cluster. The combination of foaming agent and accelerator of hardening with viscosity agent and small grain size of fine aggregate may help the dispersion of $TiO_2$ inside cementitious materials. Even though the enhanced dispersion were applied to the specimen, NOx removal efficiency doest not change much for the top surface of the specimen. This concurrently affected by the presence of tiny air voids and the dispersion of $TiO_2$ in that these voids could easily adsorbed NOx gas with the aid of large surface area.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.35 no.1
• /
• pp.97-104
• /
• 2002

Protein hydrolysate was prepared as a natural flavor stock from the sharp toothed eel (Muraenesox cinereus) mince using com-mercially available proteolytic enzymes, Alcalase, Neutrase, Protamex, and Flavourzyme. A 6 hr hydrolysis of mince, to which water of the equal weight of the mince was added, with $2\%$ (w/w, protein weight) Elavourzyme at $50^{\circ}$ yielded a hydrolysate of the highest acceptability. Removing the access lipid in liquified hydrolysate (not dehydrated) after enzyme hydrolysis, five times repetitive extraction using n-hexane (liquified hydrolysate : n-hexane=4 : 1, v/v) was effective, resulting in less than $1\%$ lipid content of the dehydrated-hydrolysate. The amino acid composition of the hydrolysate (prepared with Flavourzyme) was similar to that of the starting material. Hydrolysis led to an increase in concentration of not only total free amino acid but also free amino acid such as serine, glutamic acid, alanine, and methionine responsible for umami taste, especially up to about 40 times for methionine. Major free amino acids in amount were leucine, phenylalanine, valine, alanine, and isoleucine and they comprised about half of the total free amino acids, Moisture adsorption, fat adsorption, emulsifying capacity, and foaming capacity of the hydrolysate were 870.1 $\pm$ $7.9\%$, 352.0$\pm$ $5.3\%$, 50.3 $\pm$ $1.2\%$, and $87.5\pm$ $2.5\%$, respectively, and solubility was 83$\~$$84\%$ at acid pH range of 2$\~$4.