• 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.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.15 no.4
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• pp.263-270
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• 1982

In an attempt to evaluate the nutritional quality of seaweed protein, the effects of heat treatment on the in vitro digestibility and trypsin inhibitor content in seaweed were determined. In this study, the nitrogen-to-protein conversion factors were also calculated on the basis of quantitative amino acid data. The results are as follows : 1. The in vitro protein digestbilty of red seaweeds (P. teoera anc P. suborbiculata) were ranged from 78.5 to 82.2, and green seawerd (E. linza) and brown seaweeds showed value under 80 in vitro digestibility. In general, trypsin inhibitor contents in brown seaweed were higher (0.33-0.54 mg/g) than those of red seaweeds (0.26-0.39 mg/g). And it is noted that the lowest trypsin inhibitor content was shown in green seaweed (E. linza) in spite of lowest in spite digestibility (78.5). 2. The in vitro protein digestibility of sun dried laver (P. tenera) was increased with cooling time (microwave heating), but it was not significant. Hot plate cooking raised the in vitro digestibility from 81. 1 to 84.5. The influence pot cooking time on trypsin inhibitor content was inversely proportional to in vitro digestibility. 3. Computed nitrogen factor, based on amino acid content (Factor method) and Kjeldahl nitrogen content (Kjeldahl mettled), were 5.83 (H. fusiforme)- 6.52 (P. tencra) as Factor method and 5.40 (U. pinnatifida)-6.29 (P. tenera) as Kjeldahl method. Individual value for each nitrogen conversion factor differed by species, especially in brown seaweeds. The best estimate of the protein content of seaweed can be calculated, from multiplying the summed amino acid content by conversion factor (Factor method).

• 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.5 no.3
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• pp.88-96
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• 1972

1. The present paper deals with the contents of heavy metals such as mercury, cadmium, lead and copper in 17 species of edible seaweeds collected from Jumunjin, Pohang, Pusan, Chungmu, Yeosu and Wando areas. 2. The concentration of mercury in the air-dried seaweeds ranged from 0.02 to 0.52 ppm, as shown by the following species: 0.36ppm (0.09-0.50) in Enteromorpha spp., 0.25 ppm (0.14-0.31) in Undaria sp., 0.19 ppm (0.02-0.52) in Porphyra spp., and 0.10ppm (0.02-0.24) in Laminaria spp. in that order. If these concentrations are converted to the wet bases, they will be about 1/4 to 1/5 of the present levels. In general, the samples collected from the east coast showed relatively lower levels than those from the south coast. The mercury concentrations found in the Korean seaweeds are lower than the permissible levels reported. 3. The concentration of cadmium in the air-dried seaweeds ranged from 0.02 to 1.48 ppm, and the levels in the different species showed in the following order: 0.97 ppm (0.41-1.18) in Hizikia sp., 0.33 ppm (0.03-0.63) Undaria sp., and 0.32 ppm (0.04-0.67) in Porphyra spp. The concentration of cadmium in the samples on the wet bases become 1/4 to 1/5 of the present level. The laver Porphyra spp. collected from the east coast showed relatively lower levels than those of the cultured species along the south coast. All of the concentrations are still below than the permissible levels. 4. In general, lead concentration is 0.20-1.31 ppm which is lower than the permissible level. The concentration becomes about 0.05-0.3 ppm on the wet base. 5. Copper concentration ranged from 0.90-17.0 ppn on the dry base which is about 0.2-4.0 ppm on the wet base. It is interesting to note that the samples collected from Busan region showed relatively higher levels than those sampled from other regions.

• Journal of the Korean Society of Food Science and Nutrition
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• v.34 no.4
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• pp.451-459
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• 2005

The protective effects of ethanol extracts from 5 seaweeds on the mutagenic and cytotoxic damage were evaluated. They were separately extracted using ethanol from dried samples at room temperature, and freeze-dried. The inhibition effects on the mutagenicity in Salmonella assay by Ames test and cancer cell inhibitory effect in HeLa cell, MCF-7 cell and SNU -638 cell by MTT assay were assayed. Seaweed fusiforme, sea tangle and green laver showed strong inhibitory effect against 2-nitrofluorene, sodium azide- or 2-anthramine-induced mutagenicities in Salmonella Typhimurium TA 98 and TA 100 at the level of 2.5 mg ethanol extract per plate. Cancer cell inhibitory effect was shown with all of the seaweed extracts. Green laver, sea mustard, sea tangle and seaweed fusiforme showed strong cytotoxicity against HeLa and MCF-7 cells, with inhibiting by $92\~93\%$ and $89\~92\%$, respectively. These data show that 5 seaweeds tested in this study might be potent functional foods for cancer prevention, and consumption of these seaweeds in adequate amount is recommended.

• Korean Journal of Food Science and Technology
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• v.35 no.1
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• pp.62-66
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• 2003

Physicochemical properties and mineral compositions of seaweed salts prepared with various seaweeds and concentrated sea water were determined. Ash content of sea mustard was highest (22.7%) and that of laver the lowest (9.8%). Sea mustard contained high amount of Na, while sea tangle and seaweed fusiforme contained high amounts of K and Ca. When insoluble solids were removed after incineration of dried salt, surface color of the salt whitened more due to increase in salt purity with resulting decreases in pH and oxidation-reduction potential (ORP), pH and ORP of the ashed salt decreased, and K and Ca contents increased, while Mg content decreased. Yield of seaweed salt was the highest in sea mustard, ORP was lowest in sea tangle and seaweed fusiforme, and K and Ca contents increased significantly in sea tangle and seaweed fusiforme salts. As the concentration of sea water increased, yield and purity of the salts increased with decrease in pH and ORP and increase in Ca and Mg contents. Seaweed salt showed the characteristic crystalline structure as viewed by SEM.

• Journal of the Korean Society of Food Science and Nutrition
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• v.34 no.7
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• pp.1064-1070
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• 2005

Tocopherol and tocotrienol contents of commonly consumed foods in Korea were determined by saponification or direct solvent extraction followed by normal phase liquid chromatography. All samples were locally obtained in the year of 2002 and 2003. The study included 13 meats, 15 fishes and shellfishes, 4 seaweeds, 7 mushrooms, 19 milk and milk products, 6 legumes, 12 nuts, 17 processed foods and 17 Korean traditional foods. All of the vitamin E isomers were quantitated and the results were expressed as $\alpha-tocopherol$ equivalent $(\alpha-TE)$. The relatively higher amount of vitamin E was found in beef boiled in soy, dried squid, toasted seaweed, milk powder, soritae, sunflower seeds, ramyon (instant noodle), and kochujang from meats, fishes, seaweeds, milk products, legumes, processed foods, and traditional foods, respectively. This study provided reliable vitamin E data in commonly consumed foods in Korea for the nutritional information and food composition database.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.27 no.3
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• pp.247-258
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• 1994

A total of 31 commercial dried marine food products, consisting of 14 fishes, 2 shellfishes and 2 seaweeds species were analyzed for their contents of precusors of N-nitrosamine such as dimethylamine(DMA), trimethylamine(TMA), trimethylamine oxide (TMAO), betaine and nitrate and nitrite nitrogen as factors of N-nitrosamine formation. Carcinogenic N-nitrosamines were extracted by a steam distillation apparatus and were analyzed for their components using a gas chromatography-thermal energy analyzer. N-nitrosodimethylamine(NDMA) was confirmed by a gas chromatography-mass spectrometry. The contents of betaine nitrogen in samples were in the range of $5.2{\sim}373.8mg\%$ and were significantly higher than tertiary amines such as TMA and TMAO. DMA nitrogen in those samples was in the range of trace-31.2ppm and was high, in the dried shark(31.2ppm), alaska pollack($22.9{\sim}24.3ppm$) and octopus($17.9{\sim}18.4ppm$). In dried laver and sea mustard, however, amines were not detected at all. The levels of nitrate nitrogen in the dried marine samples ranged from zero to 16.8ppm and were high in the dried stingray(16.8ppm), alaska pollack(16.3ppm) and squid($2.2{\sim}12.4ppm$), but were less than 1.0 ppm in other samples. The levels of nitrite nitrogen were lower than those of nitrate nitrogen and it was not detected in dried sea cucumber, laver and sea mustard. Twenty eight of 31 samples contained NDMA($range=1.2{\sim}86.0ppb$), which was the only volatile N-nitroso compound found. The NDMA levels of dried stingray($2.8{\sim}86.0ppb$), alaska pollack($8.2{\sim}55.5ppb$), squid($3.3{\sim}53.2ppb$), yellow corvenia($45.9ppb$) and plain dried shrimp($15.4{\sim}17.9ppb$) were high. However, it was not detected in dried sea cucumber, laver and sea mustard. Samples, containing high levels of NDMA, also contained high nitrate and nitrite nitrogen. From above results, it can be concluded that nitrate and nitrite were major factors for the formation of NDMA in dried marine food products.

• Journal of Nutrition and Health
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• v.40 no.8
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• pp.769-778
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• 2007

Using ICP-AES, we analyzed manganese content in 366 foods consumed frequently by Koreans. For the analysis, it was included a total of 366 foods such as 51 kinds of grains, 7 kinds of potatoes and starches, 7 kinds of sugars and sweeteners, 12 kinds of legumes, 11 kinds of nuts and seeds, 68 kinds of vegetables, 7 kinds of mushrooms, 33 kinds of fruits, 13 kinds of meats, 4 kinds of eggs, 48 kinds of fishes and shellfishes, 7 kinds of seaweeds, 16 kinds of milks, 8 kinds of oils and fats, 27 kinds of beverages, 34 kinds of seasonings, 13 kinds of processed foods and others. Among the grains, starches and sugars, manganese content of rice was 0.745 mg/100g. As for legumes, the content of manganese in soybean milk was 0.033 mg/100g and in black beans was 4.075 mg/100g. In nuts and seeds, the content of manganese in gingko nuts was 0.268 mg/100g while that in pine nuts was 8.872 mg/100g. Among the vegetables, manganese contents were 0.061 mg/100g in cherry tomato and 14.017 mg/100g in ginger. In mushrooms, the highest manganese content was displayed in ear mushroom at 10.382 mg/100g. Dried jujube and shrimp were found to be the fruits and fishes with high manganese contents at 2.985 mg/100g and 3.512 mg/100g, respectively. Among dairy foods, oils and beverages, manganese content was the highest in instant coffee powder at 2.577 mg/100g. Seasonings and processed foods posted 0.010 mg/100g in Sagolgomtang, instant soup and 23.846 mg/100g in pepper. In a furture, more various food for manganese content needs to be analyzed and a reliable food database should be compiled from the findings of researches in order to estimate manganese consumption accurately.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.21 no.1
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• pp.42-49
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• 1988

In order to utilize sea mustard, Undaria pinnatifida, effectively. sea mustard jam was prepared by use of physical properties of polysaccharides, mainly alginic acid and then its chemical composition, nutritive qualifies and the stability of pigments were examined. Suitable processing condition for sea mustard jam was as fellows : as the first stage, fresh sea mustard was scalded for 20 sec at $85^{\circ}C$ and dried sea mustard was dipped for 20 min in cold water for rehydration, then both sea mustards were treated by draining and chopping. Next, after adding 4 fold of $0.5\%\;K_2HPO_4$ solution to weight of chopped sea mustards, the mixed solutions were agitated for 15 min at $95^{\circ}C$, and gelated sea mustards were filterated by pressing. Flow characteristics of those sea mustard jam were regarded mixed type having pseudoplastic type and yield stress. Judging from sensory evaluation, adding $0.375\%$ of saccharin, $2\%$ of sorbitol, $0.25\%$ of citric acid and $0.5\%$ of powder of roasted soybean to sea mustard jam were suitable for enhancing taste and flavor of product. Chemical composition of products were scarcely changed throughtout processing. Jam processed by fresh sea mustard was better than dried one in contents of chlorophyll and total carotenoid pigments. In fatty acid composition, polyenoic acids of $C_{18:3},\;C_{20:4},\;C_{20:5},\;C_{22:6}$ were held high contents as known to have lowering function of cholesterol contents. It was presumed that dominant contents in free amino acids such as lysine, alanine, glutamic acid and organic acids such as citric acid, oxalic acid, $\alpha-ketoglutaric$ acid, lactic acid and succinic acid held important role for the flavor of sea mustard jam.