• Journal of the East Asian Society of Dietary Life
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• v.21 no.6
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• pp.808-813
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• 2011

This study was conducted to promote the utilization of fish paste containing skate (Raja kenojei) powder. The tested concentrations of skate (Raja kenojei) powder were 0, 1, 3, and 5%. The pH levels of the samples ranged from 6.88 to 7.00, whereas moisture contents ranged from 79.51 to 80.35%. Increasing the amount of skate (Raja kenojei) powder in the fish paste tended to decrease lightness (L) in Hunter color value while increasing redness (a) and yellowness (b). All test samples with 3 mm thickness had good flexibility and did not break even after folding four times. Overall, according to the results of our sensory evaluation, fish paste prepared with 3% skate (Raja kenojei) powder was preferred over other fish pastes. Therefore, these results suggest that skate (Raja kenojei) powder can be applied to fish paste for the purpose of high quality and functionality.

• Animal Systematics, Evolution and Diversity
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• v.11 no.2
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• pp.207-221
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• 1995

Electrophoretic analysis was performed to determine the interspecific genetic relationships of the genus Raja collected in Korea waters. We confirmed 5 species [Raja (Okamejei) meerdervoortii Bleeker, R.(O).acutispina Ishiyama, R.(O) kenojei Muller et Henle, Raja (Dipturus) kwangtungensis Chu, and R.(D.) pulchra Liu] inhabting in Korea. As results of starch gel electrophoresis, 24 genetic loci were obtained from 13 enzymic and non-enzymic proteins, and allele frequencies of each locus were calculated . Even thought their various dorsal color patterns, the mean genetic similarity among 4 conspecific populations of R.(O) kenojei showed highly close genetic relationships (S=0.966) R.(O) kenojei and R.(D) kwangtungensis which belong to different subgenus , revealed subspecific level of differentiation (S=0.829). R. (Diptuuus ) kwangtungensis was genetically much closer to Raja(Okamejei) species than to Raja (Dipturus) species group. R.(O) acutispina and R.(D) kwangtungensis were unrecorded species to Korea.

• Korean Journal of Clinical Laboratory Science
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• v.36 no.2
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• pp.173-177
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• 2004

This study is performed in order to clarify the histochemical structure, the distribution of mucous cell and goblet cell, and the histochemical properties of the mucosubstances in the middle region of intestinal mucosa and rectum of Raja kenojei. In the H&E stain, distribution of the mucous cells and acidophilic cells were a more compacted middle portion than other regions of intestine, but the former was more than the latter in the number of mucous cells to rectum. The mucosubstances were stained with aldehyde fuchsin pH 1.7-alcian blue(pH 2.5) stain and then compared to distribution of the mucosubstances used in image and microscope technology(IMT-Size5). The middle intestine of Raja kenojei was composed of mucous cells having only large amounts of mucosubstances in the distal region was much more than that of proximal region. It was two types of mucous cells to rectum, one type was the same as proximal intestine while the other had small amounts of weakly sulfated and large amounts of carboxylated mucins.

• Journal of the East Asian Society of Dietary Life
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• v.18 no.2
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• pp.207-213
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• 2008

This study examined the effects of added amounts of skate (Raja kenojei) flour on the physical and sensory properties, and consumer acceptability of Jook. As the level of skate flour increased the L-values and b-values decreased, and a-values increased. The Jook also had higher viscosity and lower spread ability values as the amount of skate flour increased. Sensory characteristics, such as color intensity, viscosity, nutty taste, and off-flavor increased significantly with the addition of skate flour. A consumer acceptability test indicated that the 3% skate flour group had the highest overall acceptability, appearance, flavor, and texture. In conclusion, to enhance the quality of Jook, a 3% addition of skate flour would be the useful.

• Food Science and Preservation
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• v.17 no.4
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• pp.435-443
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• 2010

Physicochemical and functional properties of collage from skate skin (Raja Kenojei) are examined depending on pH and NaCl concentration in the medium. The solubility decreased as NaCl concentration increased but, turbidity increased as concentration of collagen increased. Oil-holding capacity and water-holding capacity were similar to other fish skin collagens. Emulsion activity, creaming stability, and viscosity were lowest at where pH levels were isoelectric point regions of collagens. However, the higher pH values at 7.0-9.0 caused increasing foam expansion, foam viscosity, and gel strength. These results indicated that collagen from skate skin could be used as a functional ingredient for food and industrial applications.

• Journal of the East Asian Society of Dietary Life
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• v.19 no.2
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• pp.231-237
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• 2009

The principal objective of this study was to determine the quality characteristics of tofu prepared with the addition of skate (Raja kenojei) powder. The moisture, crude ash, carbohydrate, crude protein, and crude lipid contents of the used skate powder were 5.34%, 14.15%, 1.90%, 76.60%, and 2.08%, respectivly. The yield rate of the tofu did not differ significantly with the level of added skate powder; however, significant reductions in pH and a significant increase in acidity were observed. The L and b values of the tofu decreased with increases in the amount of added skate powder in the formulation, whereas the a values increased directly with the amount of added skate powder. Furthermore, hardness was increased significantly as the level of skate powder increased. In terms of overall acceptability, the preferred tofu samples were the control and the group to which, 1.0% skate powder was added.

• Journal of the Korean Society of Food Culture
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• v.23 no.2
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• pp.235-242
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• 2008

In this study, the physicochemical and microbiological properties of market-available skate (Raja kenojei) kimchi were evaluated in comparison to long-term fermented Baechu kimchi. The comparative results for the skate (Raja kenojei) and Baechu kimchi products are as follows: salt concentrations = 3.40% and 3.95%, respectively; pH and acidity values = 4.01 and 3.90, and 0.65% and 0.82%, respectively; redox potential Eh values = 119.82 mV and 123.08 mV respectively; reducing sugars levels = 15.51 mg% and 13.23mg%, respectively; ascorbic acid levels = 24.21mg% and 22.18mg%, respectively; color L-values = 46.86 and 44.54, a-values = 15.46 and 12.28, and b-values = 29.94 and 28.36, respectively; hardness properties = 11.36 kgf and 10.23 kgf, respectively; hot water soluble pectin (HWSP) contents and sodium hexametaphosphate soluble pectin (NaSP) contents = 15.23% and 17.35%, and 32.51% and 29.64%, respectively; hydrochloric acid soluble pectin (HClSP) contents = 55.1% and 53.2%, respectively; total viable cell counts = $4.78{\times}10^8$ and $1.35{\times}10^8$, respectively; lactic acid bacteria counts = $5.18{\times}10^5$ and $1.32{\times}10^5$, respectively; and yeast levels = $8.52{\times}10^5$ and $5.23{\times}10^5$, respectively.

• Journal of the Korean Society of Food Culture
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• v.23 no.2
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• pp.252-257
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• 2008

The purpose of this study was to investigate the effects of skate (Raja kenojei) flour on the functional and sensory characteristics of Mandupi. Mandupi samples were prepared with wheat flour along with the addition of different amounts of skate flour, followed by functional measurements and sensory evaluations. According to the amylograph data, the composite skate flour-wheat flour samples had increased gelatinization temperatures with increasing skate flour content; whereas initial viscosity at $95^{\circ}C$, viscosity at $95^{\circ}C$ after 15 minutes, and maximum viscosity were reduced. In terms of color values, L and b values decreased, but the a-value increased with increasing skate flour content. Furthermore, the addition of skate flour increased hardness, springiness, chewiness, and adhesiveness in the samples. Overall, based on sensory evaluations, the Mandupi containing 5% skate flour was preferred over the other samples.

• Journal of Life Science
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• v.13 no.5
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• pp.668-674
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• 2003

This study was carried out to investigate the ACE inhibitory materials of Raja kenojei. Raja kenojei was sperated to fillet and viscera, and these were extracted with hot water. Antihypertensive activity was examined by mesearing angiotensin converting enzyme ACE inhibitory activity. ACE inhibitory activity of viscera at the concentration of 2% for Day 0 showed the highest value by 71.0%. But ACE inhibitory activity of fillet at 2% showed by 29%, which was lower antihypertensive activity than viscera. The protein content of viscerial hot water extracts in proximate composition showed the highest. And also, there was a large amount of aromatic and branched aliphatic amino acids in viscera than those in fillet. For the purification of antihypertensive material in visceral hot water extracts, it was separated and collected by Sephadex G-25 gel chromatography. The fraction (B) of 111 to 160 showed the highest ACE inhibitory activity by 65.1% at the concentration of 0.05%. But the other fractions (A and C) showed lower activity than B. These results demonstrate that crude hot water extracts of viscera from Raj kenojei may be useful as functional food ingredient with antihypertensive property.

• Food Science and Biotechnology
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• v.16 no.4
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• pp.594-599
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• 2007

In this study, we evaluated whether the oral administration of chondroitin from the cartilage of Raja kenojei is effective on the progression of rheumatoid arthritis (RA), using collagen-induced arthritic (CIA) mice. Arthritis development was delayed dose-dependently in the chondroitin-treated groups. The pre- and late-treated groups receiving 1,000 mg/kg of chondroitin had clinical scores that were reduced significantly by 56.9 (p<0.05) and 43.3% (p<0.05), respectively, compared to the vehicle-treated groups. Hematoxylin eosin staining and X-ray radiography showed that the chondroitins reduced the infiltration of inflammatory cells and prevented joint destruction of the knee and paw. Reverse transcription-polyerase chain reaction analysis revealed that chondroitin administration inhibited the expressions of tumor necrosis $factor-{\alpha}$ ($TNF-{\alpha}$), $interlukin-1{\beta}$ ($IL-1{\beta}$), and $interferon-{\gamma}$ ($IFN-{\gamma}$) in joints more than the administration of vehicle. Chondroitin treatment also decreased the production of rheumatoid factors (RF), IgG and IgM, in the serum of CIA mice. These results indicate that chrondroitin administration has a protective effect involving the inhibition of pro-inflammatory cytokine production in CIA mice.