• Textile Coloration and Finishing
• /
• v.20 no.2
• /
• pp.1-8
• /
• 2008

Regenerated composite fibers are prepared from solution(styela clava tunics /poly vinyl alchol) using N-methylmorpholine-N-oxide(NMMO)/water(87/13)(wt/wt) as a solvent by dry-wet spinning. The chemical cellulose (94%, ${\alpha}$-cellulose content) used for this study is extracted from styela clava tunics (SCT, Midduck), which are treated in chemical process and mechanical grinding. The structure and physical properties of regenerated composite fibers were investigated through IR-spetra, DSC, TGA and SEM. The optimal blend ratio of SCT/PVA for spinning solution was 70/30 and the total weight was 4% concentrations in NMMO/water solvent system. The fiber density, moisture contents and the degree of swelling were $1.5(g/cm^3)$ 10.2(%) and 365(%), respectively. The crystallinity index of composite fibers are decreased as the PVA contents increased. Thermal decomposition of composite fibers took place in two stages at around $250^{\circ}C$ and $550^{\circ}C$. The best thermal stability was obtained with 30% PVA contents.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.54 no.1
• /
• pp.1-8
• /
• 2021

In order to develop value-added low-salt fermented seafood with a long shelf-life, we prepared seasoned low-salt fermented Mideoduck (Styela clava) supplemented with fermentation alcohol (SME). The SME was produced by washing and dewatering shelled Mideoduck, followed by cutting and salting for 24 h at 0℃. The salted Mideoduck was seasoned and fermented with ingredients, including garlic, ginger, monosodium glutamate, red pepper, sesame, sorbitol and sugar, for 7-8 days at 0℃. After adding 3-5% fermentation alcohol, the Mideoduck was packed in a polyester container. The salinity, volatile basic nitrogen, and amino nitrogen content of the SME was 4.5%, 20.9 mg/100 g and 92.0 mg/100 g, respectively. In comparison with the control, the addition of 3-5% fermentation alcohol showed inhibitory effects of decreased freshness, texture degradation, and growth of residual bacteria. Additionally, the SME had good storage stability and organoleptic qualities when stored at 4±1℃ for 40 days. Therefore, it is suitable for commercialization as a seasoned low-salt fermented product with a long shelf-life. The total amino acid content of the SME was 11,774.5 mg/100 g, majorly comprising glutamic acid, aspartic acid, lysine, arginine, and leucine, and the free amino acid content was 506.4 mg/100 g, majorly comprising hydroxyproline, taurine, and glutamic acid.

• Applied Biological Chemistry
• /
• v.49 no.3
• /
• pp.227-232
• /
• 2006

Styela clava (also called as rough sea squirt or leathery tunicate) is regarded as native to the northwest Pacific region including Korea and widely distributed in parts of northwestern Europe, North America and Australia. To evaluate Styela clava as a potential bioactive agent, the antioxidant activity of aceton extracts from Styela clava (whole, substance and tunic) was tested by measuring inhibitory effect of $H_2O_2$ induced DNA damage using comet assay. Also, anticancer activity on human colon cancer cell (HT-29) was investigated by MTT reduction assay. The $200\;{\mu}M$ $H_2O_2$ induced DNA damage was inhibited with Styela clava aceton extract in dose dependent manner in human leukocytes. The maximum inhibition was by 62.8, 62.1 and 78.3% at the concentration of $50\;{\mu}g/ml$ of whole, substance and tunic extracts, respectively. The aceton extracts from S. clava were also found to inhibit the growth of human colon cancer cell. The cell proliferation rates decreased to 26.9, 30.6 and 12.0% at the concentration of $500\;{\mu}g/ml$ of whole, substance and tunic extracts, respectively. These results support that aceton extracts from S. clava may be a potential candidate as a possible antimutagenic and chemotherapeutic agent.

• Fisheries and Aquatic Sciences
• /
• v.9 no.2
• /
• pp.49-56
• /
• 2006

We evaluated changes in the nutritional composition of Mideodeok Styela clava harvested during the months of January, March, and May 2005. Glutamic acid, aspartic acid, arginine, leucine, and lysine were the most dominant amino acids present. Ratios of essential amino acids to nonessential amino acids were comparable to those of many fish species, with values ranging from 0.55 to 0.61 and 0.66 to 0.67 for muscle of Mideodeok from Geoje and Tongyeong, respectively. Mideodeok seems to be a suitable source of important fatty acids as it contains high levels of polyunsaturated fatty acids. Eicosapentanoic acid EPA; 20:5n-3 and docosahexanoic acid DHA; 22:6n-3 were the most dominant fatty acids, ranging from 20.0 to 22.3% and 16.5 to 17.9% in muscle, and 20.3 to 23.2% and 15.2 to 18.8% in tunic, respectively. The total mineral fraction of Mideodeok was 22.2-27.3% of dry matter. Sodium, calcium, magnesium, and potassium were the most dominant minerals in both muscle and tunic.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.41 no.4
• /
• pp.237-242
• /
• 2008

The tunic of Styela clava(SCT) consists of a proteoglycan network. Regenerated cellulose films were prepared by solution casting and coagulation of SCT in N-methylmorpholine-N-oxide(NMMO)/$H_2O$(87/13 wt%). The crystalline structure of powdered SCT was primarily that of cellulose I. The crystalline structure of SCT films exhibited a cellulose II structure, similar to that of viscose rayon. Physical characterization of SCT films and fibers revealed an intrinsic viscosity($\eta$) of 6.35 dL/g, average molecular weight($M_w$) of 423,000 g/M, and fiber density of 1.50 $g/cm^3$ with a moisture regain and water absorption of 10.20% and 365%, respectively. The results were similar to those of cellulose films regenerated from wood pulp. Films prepared with 6 wt% SCT exhibited strong tensile strength, high water absorption, and a greater degree of elongation. Scanning electron micrographs(SEM) of film cross-sections showed a layered, sponge-like structure.

• Textile Coloration and Finishing
• /
• v.29 no.1
• /
• pp.45-54
• /
• 2017

Ultraviolet radiation have much influenced with a deep wrinkles, roughness, laxity of skin damage and pigmentation through oxidative stress and oxidative photo-damage. This study investigates the functional properties of hydrogel facial mask sheets made from agar, Styela clava tunics and Broussonetia papyrifera tunics. The skin of S. clava is covered with a hard cellulose containing glycoprotein, glycosaminoglycan and chondroitin sulfate. B. papyrifera is better known as Paper mulberry. It contains kazinol which serves as a tyrosinase inhibitor and skin whitening agent. The tensile strength of facial mask sheet was measured by universal testing machine, and the water absorption and moisture permeability of facial mask sheet were measured by dryer. Additionally, the DPPH assay and MTT assay were conducted for anti-oxidative activity and cytotoxicity of facial mask sheet. The whitening effect of the facial mask sheet was measured by tyrosinase inhibitor assay. These tests showed that the three ingredients are suitable cosmetic materials. The results reveal that they produce a high quality hydrogel facial mask sheet when the membrane contains 1%(W/V) of agar, 0.1%(W/V) of B. papyrifera tunics and 0.05%(W/V) of S. clava tunics.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.41 no.11
• /
• pp.1591-1595
• /
• 2012

Styela clava (Korean name: miduduk) tunic was produced as a byproduct after processing of S. clava. To utilize S. clava tunic, fish paste containing tunic powder was prepared, and quality characteristics were evaluated for color, textural properties, and sensory attributes. Increasing the amount of S. clava tunic in fish paste tended to decrease lightness (L), redness (a), and yellowness (b) values of the surface part of fish paste. Strength and hardness of fish paste increased with increasing amount of tunic. All test samples with 3 mm thickness showed good flexibility and did not break even after folding in half four times. For overall acceptance in the sensory evaluation, fish paste containing 1% S. clava tunic acquired a relatively higher score. These results suggest that S. clava tunic can be applied to fish paste products to improve quality and functionality.

• Fisheries and Aquatic Sciences
• /
• v.20 no.7
• /
• pp.14.1-14.8
• /
• 2017

In this study, marine tunicate Styela clava hydrolysate was produced by an environment friendly and green technology, pressurized hot water hydrolysis (PHWH) at different temperatures ($125-275^{\circ}C$) and pressure 50 bar. A wide range of physico-chemical and bio-functional properties such as color, pH, protein content, total carbohydrate content, reducing sugar content, and radical scavenging activities of the produced hydrolysates were evaluated. The appearance (color) of hydrolysates varied depending on the temperature; hydrolysates obtained at $125-150^{\circ}C$ were lighter, whereas at $175^{\circ}C$ gave reddish-yellow, and $225^{\circ}C$ gave dark brown hydrolysates. The $L^*$ (lightness), $a^*$ (red-green), and $b^*$ (yellow-blue) values of the hydrolysates varied between 35.20 and 50.21, -0.28 and 9.59, and 6.45 and 28.82, respectively. The pH values of S. clava hydrolysates varied from 6.45 ($125^{\circ}C$) to 8.96 ($275^{\circ}C$) and the values were found to be increased as the temperature was increased. The hydrolysis efficiency of S. clava hydrolysate was ranged from 46.05 to 88.67% and the highest value was found at $250^{\circ}C$. The highest protein, total carbohydrate content, and reducing sugar content of the hydrolysates were found 4.52 mg/g bovine, 11.48 mg/g and 2.77 mg/g at 175, and 200 and $200^{\circ}C$, respectively. Hydrolysates obtained at lower temperature showed poor radical scavenging activity and the highest DPPH, ABTS, and FRAP activities were obtained 10.25, 14.06, and 10.91 mg trolox equivalent/g hydrolysate (dry matter basis), respectively. Therefore, S. clava hydrolysate obtained by PHWH at $225-250^{\circ}C$ and 50 bar is recommended for bio-functional food supplement preparation.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.39 no.3
• /
• pp.331-336
• /
• 2010

The antioxidant and angiotensin converting enzyme (ACE) inhibitory harvesting times were evaluated. During February and July of 2008, Styela clava were harvested once per month, and divided into flesh and tunic parts. Each collected part was extracted with water and 70% ethanol. DPPH radical scavenging activity (RSA) for flesh part was higher than that of tunic part, and water extract of flesh harvested at April showed the highest value (53.02% at 10 mg/mL). The highest ABTS RSA was found at water extract of flesh part harvested at March. Water extracts of flesh parts harvested from March to May showed relatively higher ACE inhibitory activity, and freezing did not affect ACE inhibitory activity. The results indicated that antioxidant and ACE inhibitory activity of S. clava were variable depending on harvesting time and parts.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.36 no.10
• /
• pp.1271-1278
• /
• 2007

In this study, the ability of Styela clava or Styela plicata to reduce ethanol-induced hepatotoxicity and hepatic and leucocytic DNA damages was evaluated. Twenty four male SD rats were given 25% ethanol containing water (ad lib, p.o.) and divided into 3 groups; ethanol treated control group (EtOH), ethano1+3% S. clava (EtOH+SC), and ethano1+3% S. plicata (EtOH+SP). After 6 weeks, the supplementation of S. clava reduced the plasma ALT, ALP and LDH activities significantly (p<0.05), while S. plicata induced significant decrease in the plasma LDH activity only. The comet assay was employed to quantify the alcohol-induced DNA damage in rat hepatocytes and leucocytes. A significant protective effect on hepatic and leucocytic DNA damages was observed in S. clava or S. plicata supplemented groups compared to the EtOH control group. The hepatic DNA damage was correlated positively with plasma ALP and LDH activities. These results demonstrated that S. clava or S. plicata supplementation protected alcohol-induced hepatic and leucocytic DNA damage.