Sargassum naozhouense is a brown seaweed used in folk medicine and applied for thousands of years in Zhanjiang, Guangdong province, China. This study is the first time to investigate its chemical composition and antiviral activity. On the dry weight basis, this seaweed was constituted of ca. 35.18% ash, 11.20% protein, 1.06% lipid and 47.73% total carbohydrate, and the main carbohydrate was water-soluble polysaccharide. The protein analysis indicated the presence of essential amino acids, which accounted for 36.35% of the protein. The most abundant fatty acids were C14:0, C16:0, C18:1 and C20:4. The ash fraction analysis indicated that essential minerals and trace elements, such as Fe, Zn and Cu, were present in the seaweed. IR analysis revealed that polysaccharides from cultivated S. naozhouense may be alginates and fucoidan. The polysaccharides possessed strong antiviral activity against HSV-1 in vitro with EC(50) of 8.92 μg/mL. These results demonstrated cultivated S. naozhouense has a potential for its use in functional foods and antiviral new drugs.
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Seaweed is a famous delicacy in some parts of the Asia and also a well-known source of important food hydrocolloids, such as agar, alginates, and carrageenan. In addition to the food value of seaweed, several health benefits have also been reported to be present in this valuable food source. It is presumed that the unique features of the marine environment, where the seaweeds are grown, are mainly responsible for most of its properties.
Among the functional effects of the seaweed, nutritional and health-related benefits have been widely studied. Compared to the terrestrial plants and animal-based foods, seaweed is rich in some health-promoting molecules and materials such as, dietary fiber, o-3 fatty acids, essential amino acids, and vitamins A, B, C, and E. In this chapter, the nutritive value of seaweed and the functional effects of its soluble fiber are discussed with a special reference to the digestive health promotion of human.
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Fresh seaweeds, both wild and cultivated, are commonly eaten as food in the Hawaiian Islands. Before Western contact, limu (seaweed) was a regular part of the diet, and is thought to have contributed vitamins and essential mineral nutrients not found in other staple food items. Twenty-two species of edible Hawaiian macroalgae (6 Chlorophyta, 4 Phaeophyta, 12 Rhodophyta) were analyzed for protein, lipid, carbohydrate, ash, caloric, mineral and vitamin content.
Halymenia formosa and Porphyra vietnamensis ranked highest in total protein content among the species analyzed.Most species contained less than 5%crude lipid, although two Dictyota species had over 16% crude lipid based on dry weight. Soluble carbohydrates ranged from 4.5 to 39.9% dry weight. Ash values ranged from 22.4% to 64.2%. Dictyota sandvicensis and Monostroma oxyspermum had caloric content each over 3000 cal g−1 ash-free dry weight. All species contained measurable quantities of 11 essential mineral elements. The majority of Hawaiian seaweeds tested contained β-carotene (vitamin A), and Enteromorpha flexuosa contained the highest amount of vitamin C (3 mg g−1).
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In the Hawaiian Islands, seaweeds and seagrasses are eaten by green turtles, Chelonia mydas Linnaeus. Sixteen macroalgal species (7 Chlorophyta, 2 Phaeophyta, 7 Rhodophyta), two seagrass species, and multi-specific algal turf from turtle foraging areas on four different islands were analyzed for proximate (protein, lipid, carbohydrate), water, ash, energy, amino acid, vitamin, and mineral content. Pterocladiella capillacea (Gmelin) Santelices and Hommersand, a prominent dietary item, and Rhizoclonium implexum (Dillwyn) Kützing, an infrequently consumed species, ranked highest in total protein content. Most species contained < 10% crude lipid. Soluble carbohydrates ranged from 3.2%–39.9% dry weight. Ash values ranged from 13.7%–81.4% dry weight. Energy content of P. capillacea was over 14 kJ g–1 ash-free dry weight. All species tested contained measurable quantities of 11 minerals. Vitamin A (β-carotene) was detected in all marine plants tested; most contained Niacin (B3 ); and Enteromorpha flexuosa (Wulfen) J. Agardh had the highest amount of vitamin C (3 mg g–1). Samples contained measurable amounts of all essential amino acids, except for tryptophan. These data provide new information about Hawaiian green turtle feeding ecology and factors that may influence somatic growth rates.
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The nutritional values of protein concentrates (PCs) isolated from two subtropical red seaweeds, Hypnea charoides Lamouroux and H. Japonica Tanaka, were evaluated in growing rats. The protein quality of the two seaweed PCs was determined by comparing the net protein ratio (NPR), true protein digestibility (TD), nitrogen balance (NB), biological value (BV), net protein utilization (NPU) and utilizable protein (UP) of the two seaweed PCs diet groups with those of the casein control group. There were no significant differences of NPR and BV in all diet groups. Although the values of TD (ranged from 90.5 to 90.6%), NB (ranged from 108 to 113 mg rat1 day1), NPU (ranged from 80.1 to 81.3%) and UP (ranged from 80.1 to 81.3%) of these two PCs were significantly lower than those of the casein control, they were comparable to those of other common plant PCs. The growth performance of rats fed the two PCs diets was satisfactory and both PCs had no adverse effect on the weight of their major organs. Together with their good protein quality as mentioned above, the PCs from the two red seaweeds under study could be a potential alternative protein source for human nutrition.
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The nutritional values of protein concentrates (PCs) isolated from two subtropical red seaweeds, Hypnea charoides Lamouroux and H. japonica Tanaka, were evaluated in growing rats. The protein quality of the two seaweed PCs was determined by comparing the net protein ratio (NPR), true protein digestibility (TD), nitrogen balance (NB), biological value (BV), net protein utilization (NPU) and utilizable protein (UP) of the two seaweed PCs diet groups with those of the casein control group.
There were no significant differences of NPR and BV in all diet groups. Although the values of TD (ranged from 90.5 to 90.6%), NB (ranged from 108 to 113 mg rat−1 day−1), NPU (ranged from 80.1 to 81.3%) and UP (ranged from 80.1 to 81.3%) of these two PCs were significantly lower than those of the casein control, they were comparable to those of other common plant PCs. The growth performance of rats fed the two PCs diets was satisfactory and both PCs had no adverse effect on the weight of their major organs. Together with their good protein quality as mentioned above, the PCs from the two red seaweeds under study could be a potential alternative protein source for human nutrition.
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Studies were conducted to evaluate nutritional qualities of two edible green seaweeds, Caulerpa lentillifera and Ulva reticulata, with a view to their utilization in human nutrition. The proximate composition, mineral and vitamin contents, free fatty acid, and amino acid profiles were investigated.
Protein and ash contents were the two most abundant components in these seaweeds. Caulerpa lentillifera and Ulva reticulata contained 12.49%, 21.06% protein and 24.21%, 17.58% ash based on dry weight, respectively. Both seaweeds contained high amounts of minerals and balanced amino acid profiles. Regarding the Dietary Reference Intake, both kinds of seaweeds were notably rich in iodine. Caulerpa lentillifera was also rich in phosphorus, calcium, magnesium and copper, while Ulva reticulata was rich in potassium, manganese and ferrous.
Comparisons to corresponding nutrient values in other seaweeds and some commonly consumed local vegetables, both seaweeds showed their potential of being health food for human diets or as source of ingredients with high nutritional values.
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Seaweed is a food ingredient that abundant availability and high nutritional content. The chemical composition of seaweed differs depending on geographical and seasons and the environmental factors. This present study aim is to evaluate the nutritional composition, including proximate and mineral analysis, of green algae Ulva sp. from Sepanjang coast for utilization in the future for functional food. The results of the nutritional analysis of Ulva sp. show that the dominant element in the proximate analysis of Ulva sp. was carbohydrate (49.09%). Moisture, ash, fat and protein content were 9.89%, 31.4%, 0.38%, and 9.24% respectively, while crude fiber was 3.68%. The sodium and magnesium were dominant minerals than other minerals in Ulva sp. According to the results of this study, Ulva sp. from Sepanjang coast, Gunungkidul has the potential as an alternative source of an ingredient food for health benefits in the future.
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This article presents information on the nutritional aspects of seaweeds in terms of fiber, mineral content, fats and lipids, vitamin contents, and components that have a confirmed and investigated nutritional effect. The nutrient levels of seaweeds are also shown in comparison to currently applicable reference nutrient intakes or guideline daily amounts of nutrients and are contrasted with terrestrial foodstuffs with respect to selected nutrients. For the purpose of comparison, a sample serving size of 8 g dry weight of seaweed is used to illustrate the potential contribution of seaweeds to the diet.
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Palmaria palmata (Dulse) is a red seaweed that may be a potential protein source in the human diet. Its protein content, amino acid composition, and protein digestibility were studied with algae collected every month over a 1-year period. Significant variations in protein content were observed according to the season: The highest protein content (21.9 6 3.5%) was found in the winter–spring period and the lowest (11.9 6 2.0%) in the summer–early autumn period. Most of the essential amino acids were present throughout the year. After 6-hour in vitro digestion in a cell dialysis using porcine pepsin and porcine pancreatin, the digestibility of proteins from Palmaria palmata crude powder, represented by dialyzed nitrogen, was estimated at 29.52 6 1.47%. Relative digestibility was 56%, using casein hydrolysis as 100% reference digestibility.
In vitro digestibility of proteins extracted in water was analyzed by sodium dodecylsulfate polyacrylamide gel electrophoresis using either bovine trypsin, bovine chymotrypsin, pronase from Streptomyces griseus, or human intestinal juice. Dulse proteins were hydrolyzed to a limited extent, which confirmed a rather low digestibility. Hydrolysis rate was higher with trypsin and lower with chymotrypsin compared with the two other enzymatic systems, pronase and intestinal juice, respectively. The association of algal powder and protein extract to casein and bovine serum albumin, respectively, produced a significant decrease in the hydrolysis rate of the standard proteins. In conclusion, the digestibility of Palmaria palmata proteins seems to be limited by the algae non-proteic fraction.
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