• Nutrition Research and Practice
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• v.9 no.6
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• pp.592-598
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• 2015

BACKGROUND/OBJECTIVES: Increased mass of adipose tissue in obese persons is caused by excessive adipogenesis, which is elaborately controlled by an array of transcription factors. Inhibition of adipogenesis by diverse plant-derived substances has been explored. The aim of the current study was to examine the effects of the aqueous methanol extract of laver (Porphyra yezoensis) on adipogenesis and apoptosis in 3T3-L1 adipocytes and to investigate the mechanism underlying the effect of the laver extract. MATERIALS/METHODS: 3T3-L1 cells were treated with various concentrations of laver extract in differentiation medium. Lipid accumulation, expression of adipogenic proteins, including CCAAT enhancer-binding protein ${\alpha}$, peroxisome proliferator-activated receptor ${\gamma}$, fatty acid binding protein 4, and fatty acid synthase, cell viability, apoptosis, and the total content and the ratio of reduced to oxidized forms of glutathione (GSH/GSSG) were analyzed. RESULTS: Treatment with laver extract resulted in a significant decrease in lipid accumulation in 3T3-L1 adipocytes, which showed correlation with a reduction in expression of adipogenic proteins. Treatment with laver extract also resulted in a decrease in the viability of preadipocytes and an increase in the apoptosis of mature adipocytes. Treatment with laver extract led to exacerbated depletion of cellular glutathione and abolished the transient increase in GSH/GSSG ratio during adipogenesis in 3T3-L1 adipocytes. CONCLUSION: Results of our study demonstrated that treatment with the laver extract caused inhibition of adipogenesis, a decrease in proliferation of preadipocytes, and an increase in the apoptosis of mature adipocytes. It appears that these effects were caused by increasing oxidative stress, as demonstrated by the depletion and oxidation of the cellular glutathione pool in the extract-treated adipocytes. Our results suggest that a prooxidant role of laver extract is associated with its antiadipogenic and proapoptotic effects.

• Preventive Nutrition and Food Science
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• v.19 no.1
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• pp.40-48
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• 2014

Laver is one of the most consumed edible red algae seaweeds in the genus Porphyra. Laver is primarily prepared in the form of dried, roasted, and seasoned products. We investigated the total polyphenol and flavonoid contents of laver products, and evaluated the in vitro antioxidant properties of solvent extracts from commercially processed laver products. Significant differences in the concentration of phenolic compounds were found among differently processed laver. The total phenolic content for laver extracts ranged from 10.81 mg gallic acid equivalent (GAE)/g extract to 32.14 mg GAE/g extract, depending on extraction solvent and temperature. Laver extracts contained very few flavonoids (0.55 mg catechin equivalent/g extracts to 1.75 mg catechin equivalent/g extracts). 2,2-Diphenyl-1-picrylhydrazyl (DPPH), 2,2'-azino-bis-3-ethylbenzothiazoline-6-sulphonic acid (ABTS), hydroxyl radical, and superoxide anion scavenging assays were used to determine the radical scavenging capacities of laver extracts. These assays revealed that the processing method and extraction condition affected the antioxidant potentials of laver. Antioxidant activity of dried laver, roasted laver, and seasoned laver increased in a concentration-dependent manner ($100{\sim}1,000{\mu}g/mL$). The radical scavenging activities of $37^{\circ}C$ and $100^{\circ}C$ water extracts were lower than that of a $37^{\circ}C$ 70% ethanol extract. The highest radical scavenging capacity was observed in the $37^{\circ}C$ 70% ethanol extracts of dried laver, roasted laver, and seasoned laver. Overall, these results support that notion that laver contains bioactive compounds, such as polyphenols and flavonoids, which may have a positive effect on health.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.45 no.5
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• pp.409-413
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• 2012

The physiological activities and amino acid compositions of dried lavers of Porphyra from the Jangheung, Seochen and Haenam coasts were determined. The ethanol extract of the Haenam dried laver exhibited the greatest 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity (56.1%), ferric-reducing antioxidant potential (FRAP) value(86.5 mM) and total polyphenol content (3.51 ppm) of these dried laver products. In addition, there was a strong positive correlation between the antioxidative activity and total polyphenol content of the laver products, suggesting that polyphenol compounds contribute to the antioxidant capacity in the ethanol extract of dried laver. However, there was no difference among the extracts in terms of cell proliferation activity. Fourteen combined amino acids were identified in oligopeptides from the dried laver products. Of the three extracts, that of the Haenam dried laver contained the highest levels of both free and total amino acids including alanine, glutamic acid, taurine, phosphoserine, and aspartic acid.

• Environmental Analysis Health and Toxicology
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• v.14 no.3
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• pp.75-79
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• 1999

Due to increasing marine pollution there is a great possibility that seaweed is contaminated with polycyclic aromatic hydrocarbons (PAHs). To investigate the effect of processing on PAM removal from Porphyra tenera (laver) contaminated PAH, laver was contaminated with fluoranthene known to have a strong photoinduced toxicity, followed by washings and drying, which are usual processes for dried laver preparation. Sample at each step was collected and its toxicity was evaluated using cultured animal cells as well as analyzing PAH contents. Fluoranthene level in laver was significantly lowered by sequential washings with sea water and distilled water, but not by drying. Fluoranthene content in raw laver right after contamination was 221 ppm and decreased to 130 ppm by washings with seawater plus distilled water while its level was not lurker lowered by drying process. Cytotoxicity and photoinduced cytotoxicity in mammalian cells were significantly elevated in laver extracts containing fluoranthene. Cellular arylhydrocarbon hydroxylase (AHH), one of the biomarkers for cellular accumulation of PAH, was greatly induced by laver extract contaminated with fluoranthene. These results suggest that photoinduced toxicity and AHH activity can be used to monitor contamination of seafood by PAHs. Fluoranthene accumulated in laver was efficiently removed by sequential washings with seawater and tap water for 24 hrs and 12 hrs, respectively.

• The Korean Journal of Food And Nutrition
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• v.18 no.1
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• pp.11-18
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• 2005

Angiotensin Ⅰ converting enzyme(ACE) inhibitory activities of laver(Porphyra tenera) protein hydrolysates were investigated by enzymes used for hydrolysis, molecular fractions and drying methods. For the enzymatic hydrolysis, crude laver protein, separated by filtration of water extract of dried laver extracted with 20 times(w/v) water for 3 hours at boiling temperature, were hydrolyzed with three commercial protease, Pepsin, alcalase and maxazyme NNP at optimal conditions. The yield of hydrolysis and ACE inhibitory activities of which were high in order of pepsin, alcalase and maxazyme NNP. ACE inhibitory activities of laver hydrolysates by molecular levels were high in order of 3 kDa > 10 kDa > 3∼10 kDa, and the IC/sub 50/ ACE inhibitory activities by molecular lebels were 4 mg/mL(3 kDa), 5 mg/mL(total hydrolysate), and 20 mg/mL(10 kDa), respectively. The storage stability of dried laver hydrolysates at 20℃ were strongly affected by drying methods, hot air dried of which were much stabler than freeze-dried one.

• Proceedings of the KSRS Conference
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• 2004.10a
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• pp.359-362
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• 2004

In multi-dimensional image, ICA-based feature extraction algorithm, which is proposed in this paper, is for the purpose of detecting target feature about pixel assumed as a linear mixed spectrum sphere, which is consisted of each different type of material object (target feature and background feature) in spectrum sphere of reflectance of each pixel. Landsat ETM+ satellite image is consisted of multi-dimensional data structure and, there is target feature, which is purposed to extract and various background image is mixed. In this paper, in order to eliminate background features (tidal flat, seawater and etc) around target feature (laver farm) effectively, pixel spectrum sphere of target feature is projected onto the orthogonal spectrum sphere of background feature. The rest amount of spectrum sphere of target feature in the pixel can be presumed to remove spectrum sphere of background feature. In order to make sure the excellence of feature extraction method based on ICA, which is proposed in this paper, laver farm feature extraction from Landsat ETM+ satellite image is applied. Also, In the side of feature extraction accuracy and the noise level, which is still remaining not to remove after feature extraction, we have conducted a comparing test with traditionally most popular method, maximum-likelihood. As a consequence, the proposed method from this paper can effectively eliminate background features around mixed spectrum sphere to extract target feature. So, we found that it had excellent detection efficiency.

• Korean journal of food and cookery science
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• v.14 no.1
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• pp.119-123
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• 1998

The purpose of this study was to evaluate the antimicrobial effect of green laver (Enteromorpha linza) on the muk (starch jelly) preservation. The methanol extract of green laver completely inhibited the growth of Vibrio parahaemolyticus at 500 $\mu\textrm{g}$/ml level, and inhibited the growth of Bacillus subtilis, Escherichia coli and Staphylococcus aureus at 100 $\mu\textrm{g}$/ml level. The Listeria monocytogenes was inhibited by 98.89% at the same concentration. When various amounts of green laver powder were added in muk (starch jelly), 5% of green laver powder-added muk showed very low level of total bacterial count compared with the control group. Also, green laver did not give negative sensory qualities such as color, flavor and overall quality. Five % green laver muk was selected as the most preferable sample among the green laver muks in overall quality test.

• Proceedings of the KSRS Conference
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• v.1
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• pp.421-425
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• 2006

This study was to propose the spatial analysis method of extracting the spectral characteristic of cultural grounds of lavers in marine especially ApHae-myeon, ShinAn-gun, JellaNam-do, through using various satellite images. In addition, the information of cultural grounds of laver such as the existence of illegal cultural grounds of laver distribution was extracted through using satellite images and GIS analysis methods. For the further work, the spatial analysis to extract not only cultural grounds of laver business but also artificial facilities in marine will be proposed.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.51 no.5
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• pp.510-517
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• 2018

The study investigated the seasonal and regional changes in the food components of raw laver Pyropia sp.. Samples were obtained monthly from December 2017 to March 2018 at auction markets located in Gangseo-gu, Busan (Nakdong-raw laver), Seocheon-gun, Chungnam, Wando-gun, Jeonnam and Goheung-gun, Jeonnam. The general components, heavy metals and minerals, free amino acids, total phenolic compounds (TPC), and antioxidant activities of the samples were analyzed. No significant physicochemical changes in the moisture, crude lipid, and ash contents were observed in the raw lavers tested. However, the crude protein content of Nakdong-raw laver was the highest in December 2017 at $7.20{\pm}0.28%$ and the content was higher seasonally and regionally than those of the other raw lavers. In addition, the taurine, zinc, manganese and TPC contents of Nakdong-raw laver was higher seasonally and regionally than those of the other raw lavers. The ethanolic extract of Nakdong-raw laver also had higher antioxidant activity, including as DPPH (2,2'-diphenyl-1-picrylhydrazyl) and ABTS (2,2'-azino-bis [3-ethylbenzothiazoline-6-sulphonic acid]) radical scavenging activity, although there was no significant correlation between TPC and the antioxidant activity. This study is the first analysis of seasonal and regional changes in the major food components of raw laver cultivated in Korea.

• Journal of the Korean Society of Food Science and Nutrition
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• v.42 no.12
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• pp.1893-1898
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• 2013

Seaweeds, laver, sea mustard, kelp, and fusiformis, were prepared and investigated for its antioxidant and tyrosinase inhibition activities. The extracts yield, color, total phenolic contents, antioxidative activity, and tyrosinase inhibition activity of the extract samples were measured. Hunter Lightness values of laver, sea mustard, kelp, and fusiformis extracts were 82.88, 78.53, 83.04, and 78.11, respectively. The contents of total phenolic compounds of the seaweed extracts powder, laver, sea mustard, kelp, and fusiformis were 43.23, 11.59, 10.09, and 46.59 mg/g of sample, respectively. 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity of the fusiformis extract was shown to be the highest value compared with other seaweed extracts. 2,2'-azino-bis-3-ethylbenzo-thiazoline-6-sulfonic acid (ABTS) radical scavenging activities of laver, sea mustard, kelp, and fusiformis extracts were 258.00, 219.26, 95.77, and $1186.62{\mu}mol$ trolox equivalence per gram, respectively, at the 1,000 ppm level. TBARS value of oil emulsion, samples without extracts was higher than those of the samples prepared with laver and sea mustard extracts. The inhibition rates (%) of the mushroom tyrosinase of laver, sea mustard, kelp, and fusiformis extracts powder were 25.93, 26.32, 24.76 and 20.24% at 1,000 ppm, respectively. The results indicated that laver, sea mustard, kelp and fusiformis extracts possess biological activities such as antioxidant activity and tyrosinase inhibition effect.