• Korean Journal of Fisheries and Aquatic Sciences
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• v.50 no.1
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• pp.1-7
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• 2017

The elimination of harmful heavy metals (Cd, Cr, and Pb) from sea lettuce Enteromorpha sp. was evaluated in filtered seawater over a pH range of 2.0-4.0 using citric, hydrochloric, and nitric acids. We also evaluated the quality of sea lettuce samples after release of their internal constituents into seawater solutions containing acids. The heavy metals that accumulated in raw sea lettuce after incubation for 3 days in seawater containing Cd, Cr, and Pb were, in descending order, Pb ($120.45{\mu}g/g$), Cr ($86.04{\mu}g/g$), and Cd ($18.35{\mu}g/g$). The rate of elimination of heavy metals from sea lettuce was higher at lower pH for all of the acids used. However, the color of the sea lettuce changed adversely at below pH 2.5. The heavy metals in sea lettuce samples after 10 min in seawater at pH 3.0 containing the three acids were eliminated in the order Pb (42.2-78.0%), Cd (51.8-55.3%), and Cr (14.0-32.8%). The quality of the sea lettuce was not affected when it was incubated for 30 min at pH above 3.0. The maximum elimination of heavy metals from sea lettuce occurred when it was soaked for 10 min in seawater at pH 3.0 containing citric acid.

• Proceedings of the Korean Society of Fisheries Technology Conference
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• 2003.05a
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• pp.279-280
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• 2003

Although it has been known though many morphological and physiological studies, its genetic diversity and population structure have not yet been investigated in this species. Therefore, detailed studies, in particular at the DNA level, on genetic diversity of natural populations of wild sea lettuce, and genetic relationships between natural sea lettuce and cultivated sea lettuce are necessary from the viewpoint of plant evolution. (omitted)

• Journal of Applied Tourism Food and Beverage Management and Research
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• v.9
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• pp.15-32
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• 1998

This experiment was carried out to evaluated biological availability of calcium inthe sea mustard, sea tangle and sea lettuce in the rats. Standard diets were made to supply 0.3% of Ca from CaCO3. Consequently, levels each test ingredients to be added were sets by their Cacontents. The ingredients such as sea mustard, sea tangle and sea lettuce wereadded to basal diet at levels of 15.23%, 12.66% and 23.42% respectively. Ingredients of the basal diet were soybean protein, corn oil, alpha-cellulose, methionine, choline cholride and vitamin and mineral premix. Dextrose was added at level up to 100%. Amount of soybean protein was adjustable to make all the diets isontrogenous. Rats were fed ad libitum the diets for 13 days. The results were summarized as follow: 1. Serum calcium levels of the sea mustard group(15.23%) were higher than those of the other group, but rats fed sea lettuce diets appeared to have the lowest value. 2. Ca concentration in tibia were lower in rats fed with sea lettuce, rather than in those with standard diet. 3. Ca concentration in femur of the rats fed seaweeds did not show any significant difference among groups. 4. In the liver weight in groups fed on the all experimental groups were decreased more than that in the case of the standard diet groups.

• Korean journal of food and cookery science
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• v.14 no.1
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• pp.25-32
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• 1998

To measure the contents of several heavy metal elements (Cr, Mn, Ni, Cu, Zn, Cd, Hg, Pb) in Korean seaweeds which are closely related to food resources, various seaweed samples were collected from thirteen to seventeen seaweed-producing districts. The results obtained from the experiment are summarized as follows: 1. The content of heavy metal elements in seaweeds of individual sample ranged from 0.0005 to 25.0373 ppm. Their mean levels were as follows: laver, 0.0024∼3.9297 ppm; sea lettuce, 0.0011∼25.0373 ppm; sea mustard, 0.0005∼23.5071 ppm; sea tangle, 0.0006∼4.8550 ppm. The mean levels of Cd and Pb were specially low in the samples collected from the area II in Kangwon and area Ⅸ in Kyungbook. 2. The mean levels of heavy metal elements of collected samples ranged from 0.0117 to 4.4944 ppm. Laver showed the lowest level of Hg and sea lettuce showed the highest level of Mn. Their mean levels of elements were as follows: laver, 0.0117∼2.3339 ppm; sea lettuce,0.0232∼4.4944 ppm; sea mustard, 0.0129∼1.5139 ppm and sea tangle, 0.0182∼1.7410 ppm. 3. The mean levels of heavy metal elements from several locations ranged from 0.0085 ppm to 8.4148 ppm. The mean levels of heavy metal elements in sea mustard from area V of Kyungbook were the lowest, but the mean levels of heavy metal elements in sea lettuce from area Ⅷ of Kyungnam were the highest. The mean level of heavy metal elements were as follows: laver, 0.3613∼1.1124 ppm; sea lettuce, 0.1415∼8.4148 ppm; sea mustard, 0.0729-3.1182 ppm; sea tangle, 0.0085∼0.7587 ppm. 4. Generally the heavy metal elements were detected in the seaweed samples from all locations. The mean levels of heavy metal elements varied with locations and kinds of samples. The levels of heavy metals of the samples taken from all locations from the East Sea, the South Sea, and the West Sea areas showed 99% safety range.

• Journal of the Korean Society of Food Science and Nutrition
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• v.34 no.8
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• pp.1143-1150
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• 2005

Antioxidative activities of 5 common edible seaweeds in Korea, three brown algae (seaweed fusiforme, sea mustard, sea tangle), one green algae (sea lettuce) and one red algae (laver), were examined. The antioxidative activities of ethanol extracts from these seaweeds were examined by measuring of inhibition rates against iron-induced linoleate peroxidation, DPPH (1,1-diphenyl -2-picrylhydrazyl) radical generation and MDA-BSA (malondialdehyde-bovine serum albumin) conjugation. Sea lettuce ethanol extract showed the strongest anti-oxidative activity among them, especially in inhibition against conjugation of lipid peroxide and protein. Second to sea lettuce, laver and sea tangle ethanol extracts showed high DPPH radical scavenging activity and inhibition against MDA-BSA conjugation. However, seaweed fusiforme and sea mustard ethanol extracts did not show antioxidative activities. Sea mustard contained the highest total flavonoids (11.33 mg/g dry wt) and sea lettuce contained the highest total polyphenol (8.97 mg/g dry wt) among these seaweeds. In addition, there was strong positive correlation between the antioxidative activity and total polyphenol content in these seaweeds, suggesting polyphenol compounds may contribute to antioxidative effect of seaweeds. From these data, it is suggested to consume much of seaweeds such as sea lettuce, laver and sea tangle to prevent age-related chronic diseases, and also develope neutraceutical products using polyphenol rich fraction from sea lettuce.

• Journal of Life Science
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• v.11 no.6
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• pp.568-573
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• 2001

Sea lettuce(Monostrima nitidum) were treated with several alkali agents on condition with water blanching at 9$0^{\circ}C$ for 10 min., and followed by drying and powdering, thus, the power samples treated and the not treated were then allowed to be stored at $25^{\circ}C$, dark place for 5 months. The sea lettuce powder samples were evaluated for green color intensity and volatile flavor at a month intervals. The green intensity of the samples were measured by using Hunter-lab colorimeter, therefore, the decoloration of greenness were seen in both of the samples treated and the not treated, but there were slight inhibitory effects on decoloration in the treated with alkali agents, especially in the treated with KHCO$_3$.The volatile flavor of the samples were collected by simultaneous distillation-extraction, and then the 31 flavor compounds were separated on HP-5 capillary column(25m$\times$0.25mm i.d) and identified by using GC-MS. From these results, it was presumed that the characteristic impact flavor compounds were $\beta$-cyclocitral, $\beta$-cyclohomocitral, ionene, $\alpha$-ionone and $\beta$-ionone. The total content of the characteristic impact flavor compounds decreased in the samples treated with alkali agents more alkali agents more than in the not treated, but lee decrease was observed in the treated with KHCO$_3$.

• ALGAE
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• v.33 no.1
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• pp.109-125
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• 2018

Turkish towel (Chondracanthus exasperatus), Pacific dulse (Palmaria mollis, also known as Red ribbon seaweed), and sea lettuce (Ulva spp.) were cultivated in a land-based intensive culture system at the Manchester Research Station, USA from August 2013 to September 2014. Macroalgae were grown in tumble-aerated tanks, harvested bimonthly for seasonal growth calculations, and analyzed for protein, lipid, ash, and amino acid content. Growth rate of all three species exhibited a similar pattern, with the highest specific growth rates occurring during the summer months (Turkish towel: 7.8%, Pacific dulse: 8.2%, and sea lettuce: 6.2%). Growth of all three species was lowest around winter solstice; with negative growth only observed in sea lettuce. On a dry weight basis significant differences in protein content existed between the three species with highest values for sea lettuce ($29.5{\pm}1.4%$). Lipid content varied between species (0.95-2.78%) with significantly higher lipid observed in sea lettuce (0.58-4.82%). No significant differences were detected on a seasonal basis among each species. Essential amino acids accounted for $43{\pm}0.9$ to $47{\pm}1.2%$ of total amino acids with Turkish towel having the highest value. Turkish towel had a significantly higher taurine level ($0.82{\pm}0.27$) than the other macroalgae. The levels of persistent organic pollutants and heavy metals were low. The estimated annual product of the three species ranged from 50- to $70-mt\;dry\;weight\;ha^{-1}\;y^{-1}$, significantly higher than conventional crops. Land-based culture of these species can produce year-round harvest, consistent product quality, and low contaminant levels.

• Journal of the Korean Society of Food Science and Nutrition
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• v.21 no.5
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• pp.544-550
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• 1992

This study was investigated on the antitumor effects of protein-polysaccharide fraction(PPF) extracted from seaweeds such as sea-lettuce and gonpi toward sarcoma-180 cells. In the PPF extracted from these seaweeds, the polysaccharide contents of sea-lettrce and gonpi were 52.20% and 48.16%, respectively. The highest levels of constituents monosaccharides found in seaweeds was fructose. The major amino acids were aspartic acid, glutamic acid, glycine and cystein. The solid tumor growth inhibition showed the highest level of 64.55% when 50mg/kg sea-lettuce was administerated. The life prolongation effect was 18.31% at 50mg/kg of gonpi. In the effects of immunologic activity, when 50mg/kg sea-lettuce was administrated, the number of circulating leucocyte showed the highest level (65.11%). The number of total peritoneal exudate cells of the sea-lettuce administerated group was increased significantly in comparison with the control group. The hematological analysis of the experimental group was similar with that of the control group.

• Journal of Nutrition and Health
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• v.29 no.3
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• pp.296-306
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• 1996

The ultimate aim of this study is to find high-fiber sources among Korean common foods and to develop a high-fiber supplement which can be useful in the therapeutic diet for the diabetic patients. For this purpose the effect of four kinds of seaweeds(mixture of purple laver & sea lettuce : MPS, sea tanle : ST, sea mustard : SM, agar agar : AA) on the glucose and lipid mtabolism were examined. Seven groups of normal and streptozotocin-induced diabetic rats were fed dietary fiber-free control diet or one of experimental diets containing 7% of one of four seaweeds for six weeks. The effects of seaweeds were campared with the effects of fiber-free diet or pectin diet. ST, SM, and AA showed a tendency of improving glucose tolerance improvement by those seaweeds, however, was less than that by pectin. MPS was found to possess a serum cholesterol-lowering effect which is comparable to that of pectin. All the supplementations of seaweeds induced significant increase in fecal steroids excretion. The amounts of fecal cholesterol excretion follwing in feeding of MPS and SM were as high as the level cause by pectin. The excretion of bile acids in the MPS group was much higher than that in the pectin group. Based on its effects of alleviating the diabetic symptoms in the previous study and of improving the glucose tolerance, sea mustard seems to have a benefical effect on glucose metabolism. The serum cholesterol-lowering effect of MPS possibly due to the significant increase in fecal steroids excretion suggests that MPS may be effective in improving abnormalities of lipid metabolism. Therefore, sea tangle and mixture of purple laver & sea lettuce seem to be promising as an effective source of high-fiber supplement for the diabetic patients.

• Journal of Aquaculture
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• v.1 no.2
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• pp.121-133
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• 1988

Strongylocentrotus pulcherrimus is one of the very important fishery stock in this country since its high demand for raw gonad. Although the demand has been continuously increasing, the natural stock of this species seems to be decreasing. Since fresh macroalgae are not always available, the substitution of terrestrial vegetables for algae as a principal food was examined for the intensive indoor culture of the sea urchin. The results from the studies on selective and non-selective feeding habits and nutritional efficiencies using 13 food stuffs (6 macroalgae, 5 vegetables and 2 animal products) indicate that algae can be substituted with vegetables in sea urchin culture. Although the growth of body weight was the highest when sea urchins were fed Undaria Pinnatifida, the gonad index of the sea urchins fed on spinach, radish leaf and lettuce was higher than that of this brown alga. Considering the different food efficiencies of body and gonad growth, spinach and radish leaf will be adequate during gonad growth season, while lettuce and Chinese cabbage will be suitable for test growth season. In particular, radish leaf, which is usually not eaten by humans, could be highly beneficial and very economical in the sea urchin culture.