Jae-Ho Hwang

Molecular species of collagen in pectoral fin cartilage of skate (Raja kenojei)

Soluble collagen was prepared from the pectoral fin cartilage of skate (Raja kenojei) by limited pepsin digestion. It was fractionated into three fractions by differential salt precipitation. All collagen fractions were further purified by phosphocellulose column chromatography and were characterized with respect to solubility, mobility on SDS–PAGE, peptide map, and amino acid composition. The resultant data indicate the distribution of three molecular species of collagen, corresponding to Type I and II as major collagens and Type XI as a minor collagen, respectively.

Molecular species of collagen from wing muscle of skate (Raja kenojei)

Abstract Soluble collagen was prepared from skate ( Raja kenojei ) wing muscle by limited pepsin digestion. It was fractionated into two fractions, major and minor, by differential ammonium sulfate precipitation. Two collagen types were purified from the major and minor collagen fractions by phosphocellulose column chromatography and were identified as Type I and V collagens, respectively, by SDS-PAGE, peptide mapping, and amino acid analysis.

Variation in the Chemical Composition of Saccharina Japonica with Harvest Area and Culture Period

Saccharina japonica is commercially important marine brown algae which grow as a single blade (reaching 10 meters in length) with a short stipe. In this study, the edible brown weed Sacchaina japonica was assessed for nutritional composition. Samples were collected monthly from seaweed farms at Kijang and Wando on the south coast of the Republic of Korea, during the 2011 culture season. S. japonica in Kijang and Wando showed the highest crude protein content in February and the highest carbohydrate content in July. Monthly changes in sugar, fatty acid, mineral, and total amino acid contents observed from February to July 2011. Fucose was the most abundant and galactose the second most abundant in the monosaccharide composition profiles, while mannose, glucose, xylose, ribose, and rhamnose were present in low quantities and lactose, mannitol, and arabinose were not detected. Significant increases of the major fatty acids in Kijang (C18:2 n-6 and C20:4 n-6) and Wando (C18:3 n-6) were observed as the culture period progressed. The highest mineral content of both Kijang and Wando samples is potassium and followed by sodium, calcium, magnesium, and so on. In the total amino acid contents, Kijang samples increased from February to April but decreased from May to July, while Wando samples increased on March but decreased from April to July.

Biochemical characteristics of four marine fish skins in Korea

In this study, we investigated the biochemical characteristics of the fish skins of four industrial species: olive flounder (Paralichthys olivaceus), black rockfish (Sebastes schlegeli), sea bass (Lateolabrax maculatus) and red sea bream (Pagrus major). There is high domestic demand in Korea for farming of these fish for human consumption. Crude protein contents in the skin of these fish ranged from 73% to 94% by dry weight; this was in part due to a high content of the structural protein, collagen. Among the four species, olive flounder had the thickest dermal and epidermal layers in the dorsal skin. This species was also associated with the highest extraction ratio of acid-soluble collagen. We also examined whether fish skin could be a cost-effective alternative to current fish meal sources. Our analysis indicates that, when supplemented with additional fish oils and essential amino acids, fish skin is a viable alternative for fish meal formulations.

Characterization of angiogenesis inhibitor effect of green tea seed extract

Abstract Green tea seed was extracted with absolute ethanol, and the green tea seed extract (GTSE) was subjected to assays for toxicity, antioxidant ability, angiogenesis inhibitory effects and cell adhesion, as well as western blotting, and an in vivo experiment against 4 high‐ranking adult cancers in Korea. Our series of experimental data demonstrated that GTSE has an antioxidant ability superior to that of EGCG in the green tea leaf, and also exhibits a profound high tumor growth inhibitory activity on a variety of cancer cell lines, as well as nude mice infected with cancer cells. GTSE was identified as a natural anticancer compound showing excellent angiogenesis inhibition and cancer cell suppression abilities. Our preliminary observations also indicate that GTSE may be another potential source of natural dietary antioxidants and also may be applicable as a novel natural anticancer agent.

Body Composition of Black Rockfish Sebastes schlegeli Fed on Diets Containing Different Levels of Turmeric Curcuma longa L.

This study investigated the effect of diets supplemented with different levels (0, 1, 3, and 5 %) of turmeric Curcuma longa L. powder (TP) on the body composition of black rockfish Sebastes schlegeli. Fish weighing g were fed to apparent satiation twice daily for 8 weeks. Adding TP decreased crude lipid levels and increased crude protein and ash levels. Abundant fatty acids in the TP-added group were C16:0, C18:1 n-9 (cis), and C22:6 n-3. The major amino acids in samples were glutamic acid, aspartic acid, glycine, leucine, alanine, lysine, and arginine.

Nutritional Characteristics of Juvenile Black Rockfish Sebastes schlegeli Fed a Diet of Fig Leaf Extract

The present study investigated the effect of diets supplemented with different levels (0, 1, 3, and 5 %) of fig leaf ethanol extract (FLEE) on the nutritional composition of black rockfish Sebastes schlegeli. Fish () were fed to apparent satiation twice daily for 8 weeks. Adding FLEE decreased crude lipid levels and increased crude protein and ash. Among the three organic acids in the whole body of black rockfish, lactic acid was predominant, followed by citric acid and oxalic acid. Five free sugars were found in all groups. Fucose and glucose were the dominant free sugars in the FLEE-added group. The abundant fatty acids in the FLEE-added group were C16:0, C18:1-cis (n9), and C22:6n-3. The major amino acids in the samples were glutamic acid, aspartic acid, glycine, leucine, alanine, lysine, and arginine. The abundant free amino acids in the FLEE-added group were taurine, glutamic acid, alanine, leucine, and arginine.

Nutritional characteristics of black rockfish (Sebastes schlegeli) fed a diet of fish skin.

This study investigated the effects of diets substituted with different levels (0, 5, 10, and 20%) of flounder skin meal (FSM) on the nutritional composition of black rockfish Sebastes schlegeli. Fish (10.05 ± 0.44 g) were fed to apparent satiation twice daily for 8 weeks. Adding FSM decreased crude lipid levels and increased crude protein and ash. The abundant fatty acids in the FSM-added group were C16:0, C18:1-cis (n9), and C22:6n-3. The major amino acids in the samples were glutamic acid, aspartic acid, glycine, leucine, alanine, lysine, and arginine. The abundant free amino acids in the FSM-added group were taurine, glutamic acid, alanine, leucine, and arginine. Six free sugars were found in all groups. Glucose was predominant, followed by mannose, rhamnose, fucose, fructose, and ribose. Among the three organic acids in the whole body of black rockfish, lactic acid was predominant, followed by citric acid and oxalic acid. Total organic acid content in the control was significantly higher than those of FSM substitution groups.

Morphological and Molecular Classifications of Genus Pholis

Abstract Morphological and molecular classifications were attempted in an effort to establish species‐specific classifications of three species of the genus Pholis in Korea; these species were subjected to morphological and molecular methodologies using body measurements, RFLP, RAPD, and phylogenetic trees using the nucleotide sequences of mitochondrial 16S and 12S ribosomal DNAs, cytochrome c oxidase I, and cytochrome b. The data demonstrated that the three species of genus Pholis are distinct from each other, both morphologically and genetically.