• Proceedings of the Korean Society of Crop Science Conference
• /
• 2018.10a
• /
• pp.274-274
• /
• 2018

Anthocyanins has a strong antioxidant capacity but exhibit poor stability in water. Therefore, stability of anthocyanin from purple potato (Solanum tuberosum L.) was encapsulated by the application of food polymers. Solid formulation of purple potato was prepared using whey protein, tapioca and lecithin by capillary rheometer at $80^{\circ}C$. The ratio of the polymer and potato powder was 2:8. Total phenolic compound, total flavonoid, total anthocyanin and antioxidant activity was investigated by the spectrophotometer. Result revealed that total phenolic compound (TP) ($5321{\mu}g/100g$), total flavonoid (TF) ($1352{\mu}g/100g$) total anthocyanin (TA) ($764{\mu}g/100g$) and free radical antioxidant activity (DPPH) (86%) was higher in 0.01 M acetic acid mediated lecithin based formulation compared to control (Potato powder) (TP: $1357{\mu}g/100g$; TF) ($634{\mu}g/100g$, TA) ($264{\mu}g/100g\;DPPH$) (64%). Lecithin is a strong emulsifier having capacity to extract bioactive compound and encapsulate extracted compound by nonpolar tail and negatively charged head. Therefore, it would be concluded that lecithin might be used as an encapsulating agent for the bioactive compound from purple potato.

• Korean Journal of Materials Research
• /
• v.31 no.7
• /
• pp.386-391
• /
• 2021

The formation of CaCO₃ in microalgal culture is investigated and applied for effective separation of microalgae. The presence of several cationic ions in the culture medium mediates the formation of 3 types of mineral precipitates depending on the concentration of mineral precursors, Ca²⁺ and CO₃^2-, amorphous nano-flakes, rhombohedral calcites, and spherical vaterites. While amorphous phased precipitates are formed for all concentrations of mineral precursor, only calcites are formed for 30 mM solutions of mineral precursor, and mixtures of calcites and vaterites are formed for 50 and 100 mM solutions of mineral precursor. The harvesting efficiency is also dependent on the concentration of the mineral precursor: from 90 % for 10 mM to 99 % for 100 mM after 60 mins' of gravitational sedimentation. The formation of nano-flakes on the surface of microalgal cells induces the flocculation of microalgae by breaking the stable dispersion. The negatively charged surface of the microalgal cell is compatible not only with nano-flake attachment but also with the growth of calcitic crystals in which microalgal cells are embedded.

• Bulletin of the Korean Chemical Society
• /
• v.6 no.5
• /
• pp.312-317
• /
• 1985

${\beta}$-Glucuronidase (EC 3.2.1.31) which hydrolizes D-glucuronate from ${\beta}$-D-glucuronide was purified from rat liver, using ammonium sulfate fractionation, DEAE-cellulose chromatography, Concanavalin-A Sepharose 4B chromatography and gel filtration on Sephadex G-200. This enzyme has the molecular weight of 280,000 daltons by gel filtration and 75,000 daltons by SDS-polyacrylamide gel electrophoresis. As its funtion is reverse of detoxification in the liver, the inhibition of the enzyme was tested with extracts of several food products and medicinal herbs, some are known as anti-cancer agents. Among them, Panax ginseng and Cortnellus shiiake inhibited the enzyme competitively and the $K_1$ values were $9.22 {\times}\;10^{-2}$ and 0.102 mg/ml, respectively. These inhibitors strongly bound to DEAE-cellulose. The negatively charged amino acids, L-aspartate and L-glutamate, inhibited the enzyme, and $K_1$ value of L-aspartate was 0.80 mM. The interaction between ${\beta}$-glucuronidase and p-nitrophenyl-${\beta}$-D-glucuronide was found to involve ionic forces by the effect of ionic strength on the kinetic constant, Vmax/Km. It was inferred from these findings that cationic group at the active center of the enzyme is probably involved in attacking the substrate.

• Applied Chemistry for Engineering
• /
• v.34 no.1
• /
• pp.1-8
• /
• 2023

Polyethylenimine (PEI) is a cationic polymer that can bind to negatively charged biomaterials such as nucleic acids through strong electrostatic interactions. Based on these properties, PEI has been used as an efficient drug delivery system for a long time. However, the strong cationic nature of PEI has the problem of causing cytotoxicity by non-specific interaction with anionic biological materials in the cells. In order to overcome these problems, many researchers have developed various types of biocompatible PEI-based materials. In this review, we would like to introduce the recent developments of functional PEI and their applications in biomedical research.

• Progress in Superconductivity and Cryogenics
• /
• v.10 no.2
• /
• pp.12-15
• /
• 2008

Nano-sized dots have been formed on the buffered metal substrates using the novel approach of the electro-spray deposition, to modulate the substrate surface and induce the columnar defects in REBCO films grown on it. The $BaZrO_3$ precursor solution was synthesized and electro-sprayed out onto the negatively charged substrate surface. Using the electrostatic force, nano-sized dots can be grown and uniformly distributed on the buffered metal substrate. The height of BZO nanodots was observed above the 200nm, which are beneficial to induce the columnar defects onto the BZO as a seed. The density of BZO nanodots was also investigated and ${\sim}7.8/{\mu}m^2$ was obtained. As the deposition distance of electro-spray was shortened there was ${\sim}8times$ increase of density of nanodots. The optimization of process variables in electro-spray deposition are discussed in respect to the superconducting REBCO films processed by the Metal-Organic Deposition with the effective flux pinning properties.

• Journal of the Korean Applied Science and Technology
• /
• v.33 no.3
• /
• pp.549-559
• /
• 2016

Korean Black body fowl (Gallus gallus domesticus; Ogae) designated as a natural monument (registration number 265) has been known as a superb traditional Korean medicine. In this study, The production of peptide from the Viscera Waste of Yeonsan Ogae was optimized using commercial protease (bromelain) by response surface methodology under high pressure process. The range of processes was pressure (30 to 100 MPa), reaction time (1 to 5 h), and substrate concentration (10 to 30%, w/v). After reaction, the degree of hydrolysis, distribution of amino acids, and molecular weight of peptides were investigated. As a results, the optimization conditions were pressure 90 MPa, reaction time 3 to 4 h, and the amount of viscera meat 20% (w/v), respectively. The molecular weight of protein hydrolysates was distributed 400 to 1,000 Da. Accordingly we presumed that most products were peptides. Of those peptides, nonpolar or hydrophobic, polar but uncharged, positively charged, and negatively charged amino acids were 42.03, 26.0, 13.3, and 18.6%, respectively. Because higher amount of hydrophobic amino acids, we expected that those products would be able to utilize as the functional food ingredients.

• Analytical Science and Technology
• /
• v.24 no.4
• /
• pp.275-281
• /
• 2011

$AlPO_4$-type material was synthesized by a reaction of $Al(OH)_3$ and H3PO4 with organic templates from wastewater of detergent manufacturer. The surface of material was coated with carboxylate groups by the reaction of succinic anhydride with surface amino groups which were formed by treatment of the material with APTMS. Powder XRD patterns showed the characteristic patterns of $AlPO_4$. Morphology of the material was examined using a SEM and the functional groups were investigated by FT-IR analysis. The surface charge of a aqueous suspension was analyzed: $AlPO_4-NH_2$ has positively charged surface while $AlPO_4$-COOH has negatively charged one. They were used for the removal of toxic metals from aqueous solution. The lead ions were adsorbed on the surface by the formation of complexes with carboxylate of surface and $K_d$ was 91.1 mL/g. In conclusion, the $AlPO_4$-COOH might be applicable in the removal of toxic metal ions from aqueous system.

• Korean Chemical Engineering Research
• /
• v.43 no.4
• /
• pp.542-547
• /
• 2005

Biosorption is considered to be a promising alternative to replace or supplement the present methods for the treatment of dye-containing wastewater. In this study, the protonated biomass of Corynebacterium glutamicum was evaluated for its potential to remove two types of reactive dyes (Reactive Red 4, Reactive Blue 4) from aqueous solution. The uptakes of dyes were enhanced with decrease in the solution pH, which was likely because the biomass functional groups increased at acidic pH and the positively charged sites could bind the negatively charged sulfonate group ($dye-SO_3^-$) of dye molecules. An equilibrium state was practically achieved in 10 hr. The Langmuir sorption model was used for the mathematical description of the sorption equilibrium. The maximum sorption capacities of C. glutamicum biomass for Reactive Red 4 and Reactive Blue 4 were estimated to 112.36 mg/g and 263.16 mg/g at pH 1, and 71.94 mg/g and 155.88 mg/g at pH 3.

• Journal of the Korean Crystal Growth and Crystal Technology
• /
• v.19 no.6
• /
• pp.305-310
• /
• 2009

$TiO_2$ thin films consisting of positively charged poly (diallyldimethylammonium chloride) (PDDA) and negatively charged titanium (IV) bis (ammonium lactato) dihydroxide (TALH) were successfully fabricated on a poly (methyl methacrylate) (PMMA) by layer-by-layer (LBL) self-assembly method. By the measurement of quartz crystal microbalance (QCM), it was found that as the solution pH of TALH decreased, the deposition volume of TALH increased and the thickness of (PDDA/TALH) thin film coated on the surface of PMMA particles increased. The PMMA particles coated with the coating sequence of (PDDA/TALH)n showed the variation of color changes as a function of the number of bilayer. The number of bilayer (n) of (PDDA/TALH) thin films was 10 and 20, the values of $a^*$ and $b^*$ decreased from those of PMMA particles without coating films and the color changes was shifted to green and blue direction in the $a^*$, $b^*$ chromaticity diagram. And then, the number of n increased to 30 and 40, the values of $a^*$ and $b^*$ increased and the color changes was shifted to red and yellow direction, respectively. Finally the PMMA particles coated with $(PDDA/TALH)_{50}$ thin film showed a little same value of $a^*$ and $b^*$ with the PMMA particles without (PDDA/TALH) thin film.

• Polymer(Korea)
• /
• v.36 no.5
• /
• pp.656-661
• /
• 2012

The palladium nanoparticles were self-assembled to make Pd-POSS using POSS-$NH_3{^+}$ (polyhedral oligomeric silsesquioxane) as a crosslinker. Graphene oxide (GO) was produced by the reaction of graphite under a strong acid and oxidizer and poly(acrylic acid) (PAA) was covalently grafted on the surface of graphene to make PAA-grafted graphene through the radical polymerization of acrylic acid and GO along with a reduction process under $NaBH_4$. The nanocomposites of Pd-POSS and PAA-grafted graphene were fabricated via ionic interactions between positively charged Pd-POSS and negatively charged PAA-grafted graphene. Pd-POSS nanoparticles were attached to the surface of PAA-grafted graphene through ionic interactions. The thermal stability of Pd-POSS/PAA-grafted graphene was higher than that of PAA and PAA-grafted graphene. The composition, structure, surface morphology, and thermal stability of the Pd-POSS/PAA-grafted graphene were studied by FE-SEM, AFM, TEM, FTIR, and TGA.