• Korean Journal of Ichthyology
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• v.31 no.2
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• pp.90-100
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• 2019

This study was carried out from March to November, 2013 to investigate the fish community structure and distribution characteristics of Phoxinus phoxinus and Rhynchocypris kumgangensis appearing in Gihwacheon Stream, Pyeongchang. A total of 6 families and 19 species of fish emerged during the survey period. The dominant species were R. kumgangensis (Individuals 44.7%, Biomass 30.2%) and P. phoxinus (Individuals 27.7%, Biomass 15.9%). Endemic species were 10 species including Pseudopungtungia tenuicorpus, Coreoleuciscus splendidus, Hemibarbus mylodon, Gobiobotia brevibarba, Microphysogobio longidorsalis, R. kumgangensis, Zacco koreanus, Korecobitis rotundicaudata, Iksookimis koreensis and Coreoperca herzi. Endogenous species were P. tenuicorpus, G. brevibarba and P. phoxinus. Hemibarbus mylodon was a natural monument. Oncherhynchus mykiss was exotic species and translocated species was Oncorhynchus masou masou. The dominant species, R. kumgangensis, appeared at all survey sites. Except for St.6, the b value was more than 3.0 and the slope of K value showed positive correlation. P. phoxinus appeared in St. 3~St. 6 and St. 3 and St. 4 only showed stable populations.

• Journal of Life Science
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• v.29 no.5
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• pp.588-595
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• 2019

This study was carried out to investigate the total polyphenol content and DPPH (1,1-diphenyl-2-picrylhydrazyl) radical scavenging activity of hot water (EIW) and 80% ethanol (EIE) extracts of Enteromorpha intestinalis and the quality characteristics of Topokkidduk prepared with different amounts (0, 1, 3, and 5%) of Enteromorpha intestinalis powder (EIP). The total polyphenol contents of the EIW and EIE extracts were 2.04 and 6.73 mg tannic acid equivalents (TAE)/g, respectively. The DPPH radical scavenging activities of EIW and EIE were markedly increased in a dose-dependent manner, and were about 19.74% and 81.69%, respectively, at 10 mg/ml. The moisture content was higher at 0% EIP (p<0.05). The L value and the a value of Topokkidduk significantly decreased when the amounts of EIP increased (p<0.05), but the b value of Topokkidduk significantly increased when the amounts of EIP increased (p<0.05). Hardness, chewiness, adhesiveness, springiness, and brittleness increased with increasing EIP concentration. The cohesiveness was higher at 3% EIP, but no significant difference was noted between 0% and 1% EIP. The total polyphenol content and DPPH radical scavenging activity significantly increased upon addition of EIP (p<0.05). A sensory evaluation revealed a higher color, texture, and taste of Topokkidduk in groups containing 0% EIP, but the flavor was highest for Topokkidduk with 0% EIP added. Overall acceptability was higher at 0% EIP, but no significant difference was noted between 0 and 1%. These results suggest that Enteromorpha intestinalis has great potential as a source for natural health products.

• Korean Journal of Food Science and Technology
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• v.51 no.3
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• pp.221-226
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• 2019

This study investigated the optimal amount of shell powder (0.1, 0.2, 0.3, and 0.4%) to add to rice noodles containing 20% rice flour and compared their quality characteristics to those of wheat noodles containing a commercial alkaline reagent (added at 0.4%). As the amount of shell powder was increased, the L and b values (Hunter's color) increased. The pH, turbidity, and water absorption also increased as the amount of shell powder was increased. However, when the shell powder content exceeded 0.3%, the hardness, chewiness, springiness, and tension tended to decrease below acceptable levels. This might be because the shell powder inhibited network formation. The textural properties and pH value of rice noodles containing 0.2% shell powder were similar to those of the wheat noodles. This suggests that 0.2% shell powder may be the optimal amount to add to rice noodles when used as the alkaline reagent.

• Korean Journal of Food Science and Technology
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• v.53 no.5
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• pp.553-560
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• 2021

Theanine, the major amino acid and a sweet umami component of green tea, has anti-stress effects in humans. From green tea, theanine was extracted at 80℃ for 2 h using a low temperature, high pressure extractor, and caffeine was removed using an HP-20 column with 80% ethanol. Theanine extracts were applied to produce functional jelly using three kinds of gelling agents (I, II, and III) or various concentrations of theanine extracts (10-50%). Theanine jelly was characterized with respect to its physical properties, product stability, and physiological function. Gelling agent III (tamarind gum, xanthan gum, and locust bean gum=2:3:5, w/w/w) and S3 (35% theanine extracts) jelly exhibited the optimum textural properties with lower hardness and high springiness. Among theanine jellies, S3 exhibited optimum product stability, high 1,1-diphenyl-2-picrylhydrazyl (DPPH) scavenging, and acetylcholinesterase inhibitory activity. These results indicate that the anine extracts could be used as a neuroprotective source in the food industry.

• FLOWER RESEARCH JOURNAL
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• v.26 no.4
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• pp.202-208
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• 2018

This experiment was conducted to determine optimal hot-air drying time for producing antioxidative calendula tea. The edible calendula was dried in hot air at $60^{\circ}C$ for 5, 10, 15 hours and Hunter's color value was measured and extracted with 95% ethanol as a solvent. The contents of total polyphenol, total flavonoid, total carotenoid and DPPH (2,2 Dipheny-1-picrylhydrazyl) radical scavenging activity were investigated. The correlation between the amount of antioxidant and antioxidant activity was analyzed. As the treatment time increased, the Hunter values of L, a, and b tended to decrease, and the L value and b value decreased significantly at 15 hours. The color change was occurred in all treatments compared with the control, and the total color difference (${\Delta}E$) was the largest at 15 hours treatment. The contents of total flavonoids, total carotenoids and DPPH scavenging activity increased in the 5 hours, but decreased in the 15 hours compared to the 10 hours. The content of total polyphenol was not changed with different treatment time. A positive correlation ($p{\leq}0.01$, r = 0.610) between carotenoids and DPPH radical scavenging activity was demonstrated. The DPPH radical scavenging activity was increased at 5 and 10 hours compared to the control and decreased at 15 hours. Therefore, 5 hours or 10 hours of treatment is appropriate and further studies are needed to determine the specific treatment time.

• Korean Journal of Food Science and Technology
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• v.52 no.6
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• pp.573-579
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• 2020

The physicochemical properties and antioxidant activities of aged ginger (Zingiber officinale Roscoe) were investigated every four days during the twenty days of aging process and compared with fresh ginger. Browning intensity and redness value were significantly increased compared to fresh ginger; however, lightness and yellow values were significantly decreased. Total sugar content was the highest during the second step and decreased significantly after the third step. The content of gingerol decreased with aging whereas 6-shogaol increased from 17.7 to 34.1 times the baseline. Total phenolic and flavonoid contents were the highest during the second step and decreased in the subsequent steps. The radical scavenging activities and reducing power were the highest during the second and third steps, respectively, and then they gradually decreased. The antioxidant activities of aged ginger during the aging process showed a high correlation with browning intensity, 6-shogaol, total sugar, and total phenolic content. Therefore, our study suggested that aging during the second and third steps were effective in optimizing antioxidant activity.

• Korean Journal of Ecology and Environment
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• v.54 no.1
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• pp.12-23
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• 2021

As fish communities are sensitive to natural environmental changes as well as anthropogenic pressures, their composition and characteristics help us to assess the aquatic ecosystem health. The fish fauna and the length-weight relationship of Zacco platypus in the Seomjin River system were investigated from July 2018 to May 2019. The collected species during the survey period were 49 species belong to 14 families including 19 Korean endemic and two endangered species. According to Bray-Curtis similarities, 14 sites were divided into four groups based on the fish community composition; two groups(group A, B) and two uncategorized sites(group C, D). There were significant differences between groups A and B(analysis of similarities, R=0.722, p=0.002). A similarity percentage analysis revealed that Z. koreanus(8.55%), Micropterus salmoides(6.90%), and Lepomis macrochirus (4.90%) contributed to these differences of fish assemblages between group A and B. Group A showed higher relative abundances of exotic species such as M. salmoides and L. macrochirus, while Z. platypus and Z. koreanus which are the common species in Korea, were the most dominant species in group B. Based on the length-weight relationship of Z. platypus, b values were varied from 2.82 to 3.80, indicating that growth patterns of the species were spatially different. This study could be served as baseline data for understanding fish fauna, assessing habitat characteristics based on the fauna, and identifying health conditions of Z. platypus in the Seomjin River system.

• Korean Journal of Environmental Biology
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• v.39 no.1
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• pp.68-80
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• 2021

This study aimed to present the current status of exotic fish species, invasive species, and dominant species inhabiting the Cheonggyecheon stream. We conducted three samplings from April to October 2019. A total of 2,045 individuals from 27 species belonging to nine fish families were collected. There were five Korean endemic species (18.5%) including Coreoleuciscus splendidus, Sarcocheilichthys nigripinnis morii, Squalidus gracilis majimae, Zacco koreanus, and Odontobutis interrupta in the Cheonggyecheon stream. The dominant species was Zacco platypus (62.4%) and the subdominant species was Z. koreanus (9.8%). The length-weight analysis of the dominant species Z. platypus population showed a regression coefficient b of 3.3434 and a condition factor(k) of 0.0026, with a positive slope. The growth state of the Z. platypus population was identified as being in a very favorable condition. The Cheonggyecheon stream is considered to be an appropriate habitat for the Z. platypus population. Since the restoration, The Cheonggyecheon stream has had continuous problems due to the introduction of exotic species and invasive species and in this study, exotic species, Gyrinocheilus aymonier var.(gold type), and invasive species, Coreoleuciscus splendidus, which have not previously been reported in the Cheonggyecheon stream, appeared. Therefore, it is deemed necessary to prepare continuous publicity and management measures to prevent exotic species and invasive species from inhabiting the Cheonggyecheon stream.

• Korean Journal of Environmental Biology
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• v.38 no.4
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• pp.667-677
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• 2020

This study was conducted to investigate the fish fauna and characteristics of the Carassius auratus population in the Boryeong Reservoir in Chungcheongnam-do from October 2017 to June 2018. The collected fish were identified as 3,506 individuals of 15 species from a total of nine families. The dominant and subdominant species were H. nipponensis with 1,706 (48.6%) individuals and C. auratus with 1,021 (29.1%) individuals, respectively. The biomass of C. auratus (246,130g), P. fulvidraco(50,610g), C. cuvieri (14,730 g), S. asotus (11,560 g), and C. carpio (10,930 g) was analyzed. The results of the community analysis showed a dominant index value of 0.87 (±0.2), a diversity index value of 0.78 (±0.5), an evenness index value of 0.47 (±0.2), and a richness index value of 0.99 (±0.5). The length-weight analysis of C. auratus showed a regression coefficient b of 3.06, and a condition factor (K) of 0.0004 with a positive slope. The frequency distribution of the total length analysis of the C. auratus population inhabiting the Boryeong Reservoir showed a high distribution of lengths between 140-160 mm and a low distribution between 230-280 mm. The normalized difference water index (NDWI) was analyzed over the Boryeong Reservoir water surface from 2013 to 2014 using Landsat 8 channel data. The areas where the NDWI was decreased were located at the inflow site of Ungcheon Stream.

• Korean Journal of Food Science and Technology
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• v.52 no.6
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• pp.632-640
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• 2020

In this study, we produced macarons by adding white bean powder at various proportions (0, 25, 50, 75, and 100%). The macarons in the 100% additive group had the highest moisture content, smallest volume, highest weight, and highest sugar and reducing sugar content. The macarons in the 50% additive group had the highest spread factor.Furthermore, their pH and acidity demonstrated the greatest air bubble stability. In the Hunter color system, by adding white bean powder, the L value gradually decreased, whereas the a and b values gradually increased. The hardness, gumminess, and chewiness decreased with the addition of white beans. Flavonoids and total phenolic compounds, 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity, and superoxide dismutase (SOD)-like activity were the highest at 100%. Additionally, their overall acceptability was the highest at 50%. These results suggested that the use of white bean powder to produce macarons have numerous advantages.