• 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.

• Food Science and Preservation
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• v.10 no.1
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• pp.32-36
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• 2003

Quality stability of the dried layer Porphyra tenera depending on various light sources, water activities, packaging materials and storage temperatures were investigated by peroxide value and chlorophyll degradation. Major fatty acids of dried layer were 45.7％ eicosapentaenoic acid and 13.6% palmitic acid. Quality stability was increased in order of darkness, incandescent and fluorescent increased sharply with the decrease of water activity and temperature, and also improved by the packaging material with strong barriers of water vapor, oxygen and light.

• The Korea Journal of Herbology
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• v.30 no.2
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• pp.25-30
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• 2015

Objectives : Laver (Porphyra tenera), a red algae species, is one of the most widely consumed edible seaweed in Korea. Laver contains various substances such as essential amino acid, fiber, minerals and polyphenols that benefit human health. In the present study, we prepared ethanol extracts from commercially processed product of Porphyra tenera, and evaluated the growth inhibitory effect against human oral squamous carcinoma YD-10B cells. Methods : Cell viability was measured by MTT assay. Apoptosis was confirmed by TUNEL assay and flow cytometry with the green fluorescent dye FITC annexin V entering apoptotic cells and the red fluorescent dye PI not entering. The expression of the relevant proteins was detected using Western blot. Results : Ethanol extracts of Porphyra tenera (PTE, $50-200{\mu}g/m{\ell}$) caused a significant decrease of cell viability in a dose dependant manner. The cell death occurred as a result of apoptotic process as determined by TUNEL assay and flow cytometric analysis. In line with this observation, decrease in procaspase proteins and increase in cytosolic cytochrome c were observed in cells treated with PTE. In addition, exposure to PTE decreased the expression levels of Bcl-2, and induced PARP cleavage and AIF translocation from mitochondria to nucleus. Conclusions : In conclusion, PTE exerts anti-cancer effects by inducing apoptosis via caspase activation and AIF nuclear translocation in YD-10B cells. These results provide evidence for the possible therapeutic effect of Porphyra tenera in oral cancer cells.

• 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.

• Korean Journal of Food Science and Technology
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• v.27 no.6
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• pp.902-908
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• 1995

Oxidative factors of lipid in the roasted laver Porphyra tenera(RL) and roasted-seasoned laver(R-SL) depending on various light sources, water activities, packaging materials and storage temperatures were investigated by peroxide value and color. Major fatty acids of RL were 46.4% eicosapentaenoic acid and 14.9% palmitic acid. Lipid oxidation was decreased in order of darkness, incandescent and fluorescent, decreased sharply with the decrease of water activity and temperature, and also reduced by the packaging material with strong barriers of water vapor, oxygen and light. From kinetics of lipid oxidation, it was supposed that oxidation of R-SL was three times faster than RL. On the other hand, reduction of the total chlorophyll content in RL was stronger than R-SL.

• Journal of the Korean Society of Food Science and Nutrition
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• v.30 no.1
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• pp.193-195
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• 2001

A radiation-resistant bacterium was isolated from gamma irradiated dried laver (Porphyra tenera) and its microbiological characteristics were examined. As a result of resistance test to gamma irradiation, the isolate was survived $10^{3}$ CFU/mL even at 30 kGy and significant shoulder line zone was shown until 20 kGy. The $D_{10}$ value was 11.27 kGy. The isolate was gram-positive, non-motile coccus and catalase-positive. n culture, the red-pigmented smooth colony was observed. The biochemical test in API (analytical profile index) system showed that the isolate fermented glucose and fructose as the carbon source. Therefore, a radiation-resistant bacterium isolated from laver was potentially identified as Micrococcus roseus sp.

• Journal of the Korean Society of Food Science and Nutrition
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• v.42 no.8
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• pp.1270-1276
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• 2013

Laver, a red algae belonging to the genus Porphyra tenera, is one of the most widely consumed edible seaweeds in Korea, China, and Japan. Lavers are usually consumed in dried, roasted, and seasoned forms to improve their palatability. We evaluated the composition of amino acids, minerals, and trace heavy metals in these three differently cooked forms of laver. The moisture and ash contents of three differently cooked lavers ranged from 1.49~9.69% and 6.07~10.31%, respectively. The crude protein and lipid content ranged from 17.24~36.88% and 0.52~42.42%, respectively. Dried laver was found to be a good source of amino acids such as taurine, alanine, and glutamic acid (871.10 mg, 833.53 mg, and 719.77 mg per 100 g dry weight, respectively). Laver was a good source of macro and micro minerals such as K, Ca, Mg, Na, P, I, and Fe, although laver more extensively cooked (roasted and seasoned) contained less minerals compared to the dried form. Mercury levels in the three differently cooked forms of laver were all less than 100 ng/g dry weight (the limit of detection with our methodology). The levels of arsenic were the most abundant elements in the differently cooked laver. There was a clear variation, depending on the cooking process, in terms of amino acid, mineral, and trace metal contents of laver.

• 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.1 no.1
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• pp.19-30
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• 1968

An experiment on the culture of laver, Porphyra tenera, was carried out from September 26, 1965 to February 12, 1966 at a laver farm on the coast of Gae-do, Hwacheong-myeon, Yeocheon-gun, Jeonranam-do, using 'Sae-ol-bal' (triple-knotted blind) laver bed, resulting in the following data: 1. 'Sae-ol-bal' laver, bed was less destroyed compared to ordinary (dual knotted blind) laver bed, the destruction rate being $9.8\%$ in 'Sae-ol-bal' laver bed, while $35.3\%$ in ordinary laver bed (Table 5). 2. The quantity of laver yield is the greatest on the edge-part, the next on the basal part, and the smallest on the middle part of the 'Sae-ol-bal' laver bed (Table 6, Figs. $7\~8$). 3. The ordinary laver bed may yield better harvest on the calm farm but 'Sae-ol-bal' laver bed yields better harvest at a farm where the destruction of bed is remarkable by wind and wave action.

• Preventive Nutrition and Food Science
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• v.18 no.2
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• pp.139-144
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• 2013

Laver, a red algae belonging to the genus Porphyra, is one of the most widely consumed edible seaweeds. The most popular commercial dried laver species, P. tenera and P. haitanensis, were collected from Korea and China, respectively, and evaluated for proximate composition, amino acids, minerals, trace heavy metals, and color. The moisture and ash contents of P. tenera and P. haitanensis ranged from 3.66~6.74% and 8.78~9.07%, respectively; crude lipid and protein contents were 1.96~2.25% and 32.16~36.88%, respectively. Dried lavers were found to be a good source of amino acids, such as asparagine, isoleucine, leucine, and taurine, and ${\gamma}$-aminobutyric acid. K, Ca, Mg, Na, P, I, Fe, and Se minerals were selected for analysis. A clear regional variation existed in the amino acid, mineral, and trace metal contents of lavers. Regular consumption of lavers may have heath benefits because they are relatively low in fat and high in protein, and contain functional amino acids and minerals.