The Edible Red Algae Pyropia Yezoensis Contains Many Nutrients and Health-Promoting Compounds

Algae farming in Xiapu, Fujian Province of China Picture by Ophis Picture by The Algonauts Project

Coltivazione di alga nori Nori The edible red algae Pyropia yezoensis contains many nutrients and health-promoting compounds

Nori, one of the favorite food of the Japanese, is a dry foodstuff processed from the edible red algae Pyropia yezoensis with less than 3% moisture content and which has protein and dietary fiber as its major components. In addition, this seaweed contains high levels of iron, zinc, and manganese as well as high vitamin A, vitamin B12, folic acid and vitamin C. Nori is a good source of protein, similar to the protein content in beans and its interesting nutritional properties are widely studied.

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harvest of nori and related seaweeds has been a steady 300,000 tons, based on statistical data from Japanese fisheries (MAFF, 2017). Most of the nori is produced by aquaculture of the major species, Pyropia yezoensis, in shal- low water. By the Edo period, the aquaculture techniques had been established, and nori came to be processed in well-dried and some- times roasted paper-like sheets measuring 19 cm by 21 cm, or approximately 3 g per sheet, using traditional Japanese techniques for making paper by hand. Today, these processes are automated with specialized machines. The annual production of dried and roasted nori reached 7 billion sheets in 2015 (MAFF, 2017). Various kinds of seaweed, which contain a number of polysaccharides, vitamins and minerals, are popular foodstuffs in Japan. Nori is among them, but it has a unique Picture by holdfast… characteristic nutritional profile that sets it apart from other seaweeds. Even more remarkable is that it is a good source of nutrients that are rare in other vegetables and also has unique metabolites with health benefits, as discussed below.

dishes such as sushi and various Nutrients and flavors kinds of wrapped rice balls. Nori is Common nori is a dried product widely accepted as a good accom- with less than 3% moisture con- paniment for rice, the staple food tent and which has protein and * Tomoyuki Koyama in Japan. Here, descriptions of tra- dietary fiber as its major compo- ditional nori foodstuffs are given. nents, as shown in Figure 1. It is In recent years, the total annual low fat (3.7%) and is low in digest- Introduction ori is one of the favorite food of the Japanese, en- Njoyed for its flavor and taste, often with Cha (green tea). This simple dry foodstuff processed from the edible red algae Pyropia yezoensis (the former genus name was Porphyra) adds variety to the daily diet and offers flavor, nutrients, and other health benefits. In Japan, the algal product is commonly found in the market not just as a topping but is also included in some traditional rolled Figure 1. Nutritional Composition of Nori

settembre 2018 natural 1 t 71 ible carbohydrates (1.9%). Nori is ri’s vitamin B12 (VB12) content ishment but also adding flavor to a good source of protein, similar is equal to that found in animal meals, which enhances interest to the protein content in beans. sources such as liver paste. The in food and increases appetite, Further, based on the food com- bioavailability of VB12 from pow- therefore promoting good eating position table (MEXT, 2015), nori der has been confirmed in previ- habits. has features that are different ous animal experiments (Takena- However, identification and anal- from other seaweeds (wakame, ka, 2001) and clinical trials have ysis of nutritional components of konbu, hijiki and hitoegusa) or confirmed the bioavailability and nori have been difficult, and fla- other dried food materials (soy- effectiveness of VB12 in numer- vor components of nori have not bean, tomato and strawberry), ous nori products. In a study by been perfectly elucidated, but as shown in Table 1. The dietary Suzuki (1995), the addition of 2 previous reports have revealed fiber content of most seaweed is to 4 g per day of nori powder to some costituents. For instance, approximately 30%; however, the the brown rice-based diets of six it has been reported that pyra-

Table 1. Nutritional composition of dried seaweeds and foodstuffs

protein content of nori, at 41.4%, young vegans aged 7 to 14 years zine, gamma butyrolactone and is nearly three times that of oth- was effective in preventing a VB12 several types of hydrogen sulfide er seaweeds. Analysis of the fatty deficiency. All this indicates that (including dimethyl sulfide and acid (FA) composition (MEXT, nori contains ingredients that are methyl mercaptan) are important 2015) reveals that eicosapentae- nutritionally beneficial. in creating the flavor of roasted noic acid (EPA, or icosapentaeno- Nori is an important Japanese nori products (Osumi, 1990; Ka- ic acid, 20:5n-3) is the major FA food, not only for providing nour- sahara, 1975, 1986). The tastes in dried nori (1200 mg/100 g). It has been demonstrated that some edible seaweeds, especially Porphyra sp., contain high levels of EPA (Dawczynski, 2007). An analytical study about nori from different growing conditions elucidated that nori has a metabolic pathway, which commonly found in animals, from linolenic acid to IPA (Kayama, 1985). In addition, nori contains high levels of iron, zinc, and manganese (Esashi, 1993; Mišurcová, 2001) as well as high vitamin A (shown as beta-carotene equiva-

lent), vitamin B12, folic acid, and vitamin C content as compared to other foodstuffs (Figure 2). No- Figure 2. Characteristic nutrients of nori

72 t natural 1 settembre 2018 FOCUS - MARINE RESOURCES - NORI of foods are also provided by the water-soluble and low-molecular compounds that are extractable from the foodstuff. In this sense, nori contains abundant amino acids such as glutamic acid, aspartic acid, alanine and taurine, along with nucleic acids such as adenyl acid and inosine acid. These components have a sweet and/ or umami taste, but their levels vary according not only to the en- Figure 3. Basic structural unit of porphyran vironmental growing conditions and season but also according to of the algae (Kim, 2011). In the contain a cyclohexenimine or cy- the processing and storage con- case of red algae, some kinds of clohexenone ring linked to an ami- ditions of nori products (Harada, galactan, such as agarose, carra- no acid or its metabolites (Figure 1990). Recently, active deami- geenan, funoran and porphyran 4). nase has been purified from dried are commonly found. In partic- The compounds have strong ab- nori products, and the proper- ular, porphyran is observed as a sorption, maxima in the range ties were elucidated (Nakashima, major polysaccharide in nori. The of 310 to 360 nm, and are wide- 2000). The deaminase converts linear polysaccharide is composed ly present in marine plants and from adenyl acid, which is eluted of L-galactose (Gal) and D-galac- animals (Dunlap, 1998). These from nori to inosine acid, which is tose, with variations, including products are considered to be nat- an umami component, under the 6-O-methyl-D-Gal, 6-O-sulfate-L- ural protectors against UV radia- optimal conditions of 7.0 to 8.0 Gal and 3,6-anhydro-L-Gal (Mor- tion and related lesions. Further pH at 30–50 ˚C in the presence rice, 1983) (Figure 3). The mo- research has shown that these of water and Ca2+. The enzyme lecular size and sulfation rates products are supplied only by al- has desiccation tolerance, so it of porphyran in nori are subject gae, and the marine animals have also contributes to enhancing the to environmental factors (Hama, acquired them through the food taste of nori when it is chewed. In 1998). It is easily dissolved in wa- chain or symbiotic relationships. this way, nori adds a pleasurable ter and shows high viscosity, but Other various actions of MAA that smell and taste to daily food in- does not turn into a gel. have been reported include anti- take. A wide range of physiological ac- oxidative activities in vitro (Tao, tivities of porphyran have been 2008), growth-inducing activity Health-promoting reported, including antioxida- against fibrocytes of human origin compounds tive activity (Zhang, 2004), an- (Oyamada, 2008), and UV-protect- Various types of seaweeds are ti-inflammatory activity (Isaka, ing activities in fish eyes (Dunlap, known to be rich sources of nu- 2015), inhibitory activity against 1989). Applications in mammals trients with low calories that pro- α-amylase (Goni et al., 2000), an- are also being studied, and UV-pro- vide a number of health-promot- tidiabetic activity in KKAy mice tecting activities have been shown ing benefits. Nori also gives us an (Kitano et al., 2012), suppres- in externally applied MAA on mice effective means for balancing our sive effects on serum cholesterol skin (Coba, 2009). There is not physiological condition through levels in rat (Tsuge et al., 2004), currently enough data on in vivo its unique compounds, given the anti-tumor activity (Noda et al., functionality of MAA after oral ad- recent discoveries that more in- 1989), apoptosis-inducing activ- ministration to mammals. gredients found in foods than pre- ity (Kwon, 2006), anti-allergic Among marine algae, the red algae viously thought exhibit physiolog- activity in mice (Ishihara, 2005) group is known to be one of the ical regulating activities. Some of and much more. major producers of MAA (Karsten, these components are found in The sulfated polysaccharide that 1998). Nori contains three major nori, as introduced below. can be prepared in large quantities MAAs, mycosporine-glycine, shino- from nori is expected to be used rine and porphyra-334 (Yoshida, Porphyran for various product applications. 1970), according to pioneering re- Dietary fibers found in seaweeds search (Ito, 1977; Takano, 1979). can be classified into several Mycosporine-like amino acids Today, extracts containing these types according to structure and Mycosporine-like amino acids MAAs are used in commercial pro- activity which are closely con- (MAA) are derivatives of myco- duction of sunscreen and health nected to the taxonomic group sporine (Favre-Bonvin, 1976) that food products.

settembre 2018 natural 1 t 73 against oxidative stress. Other components Among other applications, nori has also been used as a source of organic pigments after semi-purification or as supplement tablets after enzyme treatment. Dried nori as a food product is nearly black in color, but the red alga P. yezoensis contains pigments of chlorophyll (green), ca- Figure 4. Micosporine-like amino acids rotenoid (orange), phycoerythro- bilin (red) and phycocyanobilin Galactosyl glycerols rats (Ishihara, 2010). Other in- (blue). Galactosyl glycerols (GG) such as dices of prebiotics, such as pH The bilin pigments having linear floridoside and isofloridoside are of cecal content, organic acid the major products relating to concentrations, and fecal weight, osmotic modulation in most red have also supported its prebiotic algae (Reed, 1985) (Figure 5). activity. The genus Pyropia also contains floridoside and isofloridoside, Imidazole dipeptides with the isofloridoside coexist- Anserine and carnosine are ing in two enantiomeric forms: known as imidazole dipeptides D-isofloridoside (1-O-a-D-galacto- (Figure 6), which are metabolites pyranosyl-D-glycerol) and L-iso- consisting of two amino acids, Figure 6. Imidazole dipeptides floridoside (1-O-a-D-galactopyra- histidine and beta alanine. They nosyl-L-glycerol) (Meng, 1987). are commonly found in fish such tetrapyrrole moiety, constitut- Each isomer has been identified as tuna, bonita, salmon and oth- ing phycoerythrin and phyco- with NMR techniques (Bondu, ers, and also in white meat such as cyanin, respectively, to bind to 2008), making comparison possi- chicken, goose, and turkey. How- specific apoproteins. Increasing ble through instrumental analysis ever, only a few kinds of plants water activity during storage of to measure the content of these contain these peptides. Tamura et nori accelerates the hydrolysis of galactosides in nori according to al. (1998) have found these dipep- chlorophyll and phycocyanobilin, environmental and seasonal con- tides to act as strong antioxidants finally inducing the color change ditions (Karsten, 1999). in the basic amino acid containing to reddish black. Alternatively, Recently, the compounds have fraction prepared from EtOH ex- increasing roasting treatments been found to have bifidogenic tract of nori. The concentrations to bring out flavor denatures growth stimulator activity, and were calculated as 2.20 mg anser- heat-labile phycoerythrin, finally they are the focus of research as ine and 1.60 mg carnosine in 1 g inducing a color change to clear a new prebiotic material. GG-rich of dried nori, which compares with greenish black (Fujiwara, 1961). mixtures of three isomers have typical concentrations in chicken All of these pigments have shown been purified from a 75% MeOH (3.57 mg and 1.30 mg/g, respec- strong antioxidative activity in extract of nori to perform animal tively) and fresh tuna (9.40 mg vitro and in vivo (Yabuta, 2010; experiments, and dietary GG was and 0.48 mg/g, respectively) Soni, 2009). In the mammal in- shown to selectively increase the (Hiraoka, 2011). These peptides testine, bilin pigments are easily cecal Bifidobacterium count in show antioxidant activity in vari- absorbed into the bloodstream ous in vitro assays (Kohen, 1988) after digestion of the apoproteins and lowered uric acid levels in rats by intestinal enzymes. Therefore, (Chen, 2004). In one study, anser- these large pigment molecules ine given at 25 mg per day for 4 also appear to exhibit antioxida- weeks improved hyperuricemia in tive activity in vivo. people who need to control uric Nori as a protein source can be acid levels (Kubomura, 2009), in- utilized for protease treatment dicating that an appropriate daily or fermentation to create new intake of these dipeptides may in- active components. There have crease the possibility of prevent- been some trials applying fermen- Figure 5. Galactosyl glycerols ing hyperuricemia and protect tation techniques with nori pow-

74 t natural 1 settembre 2018 FOCUS - MARINE RESOURCES - NORI der wherein lactic acid fermen- Conclusion will continue for a long time into tation of nori produced gamma This paper has given a brief over- the future. amino butyric acid (GABA) that view of nori. It is not just a tra- had a suppressive action on blood ditional edible seaweed in Japan, * Tokyo University of Marine Science pressure (Tsuchiya, 2007). Oth- but rather, it is also a superfood and Technology er research groups have reported with a lot of potential for promot- inhibitory oligopeptides against ing good health. Various unique angiotensin converting enzyme nutrients and health-promoting References (ACE) after pepsin treatment and ingredients have been found in S. Bondu, N. Kervarec, E. Deslandes, and semi-purification of nori powder this food product. Aside from R. Pichon (Suetsuna, 1998). These activities Separation of floridoside and isoflorido- providing energy, this foodstuff 1 13 and mechanisms have been con- sides by HPLC and complete H and C enhances appetite and improves NMR spectral assignments for D-iso- firmed in experiments using SHR health through daily eating habits floridoside. rats and in human clinical trials in Japan. The knowledge gained Carbohydrate Research 342, 2470–2473 (Saito, 2005). The nori oligopep- through continuous research into (2007). tides have been applied to foods J. B. Chen, H. C. Peng, and S. H. Lin seaweeds and their components Effects of chicken extract on plasma an- for specified health uses (FOSHU) will enable development of new tioxidative status and lipid oxidation in product approved by the consum- ingredients, food materials and healthy Rats. er affairs agency in the Japanese uses of them all over the world. Journal of Nutrition Science and Vitamino- market since 2005. The major Seaweeds are an important part logy, 50, 320-324 (2004). active peptide identified in these F. de la Coba, J. Aguilera, M.V. de Gálvez, of the traditional Japanese food M. Álvarez, E. Gallego, F. L. Figueroa, products from digestive nori mate- culture in promoting good health. and E. Herrera rial is Ala-Lys-Tyr-Ser-Tyr. We hope that this relationship Prevention of the ultraviolet effects on

settembre 2018 natural 1 t 75 clinical and histopathological changes, K. Ishihara, C. Oyamada, R. Matsushima, (2009). as well as the heat shock protein-70 ex- M. Murata, and T. Muraoka M. J. Kwon, and T. J. Nam pression in mouse skin by topical appli- Inhibitory effect of porphyran, prepared Porphyran induces apoptosis related sig- cation of algal UV-absorbing compounds. from dried “nori”, on contact nal pathway in AGS gastric cancer cell Journal of Dermatological Science 55, hypersensitivity in mice lines. 161–169 (2009). Biosci. Biotechnol. Biochem., 69, 1824– Life Science 79, 1956–1962 (2006). C. H. Dawczynski, R. Schubert, and G. Jah- 1830 (2005). MAFF: Ministry of Agriculture, Forestry reis K. Ishihara, C. Oyamada, Y. Sato, T. Su- and Fisheries, Japan Amino acids, fatty acids, and dietary fiber zuki, M. Kaneniwa, H. Kunitake, and T. The 91th Statistical Yearbook (2017) of in edible seaweed products. Muraoka MAFF Japan Food Chemistry, 103, 891–899 (2007). Prebiotic effect of glycerol galactoside http://www.maff.go.jp/e/tokei/kikaku/ W. C. Dunlap, D. M. Williams, B. E. Chalk- isolated from color-faded nori in rats. nenji_e/nennji_index.html er, and A. T. Banaszak Fisheries Science, 76, 1015-1021 (2010). J. Meng, K. G. Rosell, and L. M. Srivastava, Biochemical photoadaptations in vision: S. Ito, and Y. Hirata Chemical characterization of floridosides UV-absorbing pigments in fish eye tis- Isolation and structure of a mycosporine from Porphyra perforata. sues. from the zoanthidian Palythoa tubercu- Carbohydrate Research, 161, 171–180 Comp. Biochem. Physiol. 93B, 601–607 losa. (1987). (1989). Tetrahedron Letter, 28, 2429–2430 MEXT: Ministry of Education, Culture, T. Esashi, and M. Hanai, (1977). Sports, Science and Technology, Japan Bioavailability of magnesium contained U. Karsten, T. Sawall, and C. Wiencke Standard Tables of Food Composition in purple laver (Asakusa-Nori) by rats A survey of the distribution of UV-absorb- in Japan 2015 (7th revised edition in with scarce magnesium, being evaluated ing substances in tropical macroalgae 2015) from serum magnesium, kidney calcifi- Phycological Research, 46, 271-279 http://www.mext.go.jp/en/policy/scie cation, and bone magnesium contents. (1998). nce_technology/policy/title01/detail0 Journal of Nutritional Science and Vita- U. Karsten 1/1374030.htm minology, 39, 381-387 (1993). Seasonal variation in heteroside concen- L. M. Morrice, M. W. McLean, W. F. Long, J. Favre-Bonvin, N. Arpin, and C. Brevard trations of field-collected Porphyra spe- and F. B. Williamson Structure de la mycosporine (P 310). cies (Rhodophyta) from different bio- Porphyran Primary Structure. Canadian Journal of Chemistry, 54, geographic regions. European Journal of Biochemistry, 133, 1105–1113 (1976). New Phytology, 143, 561–571 (1999). 673-684 (1983). T. Fujiwara K. Kasahara, J. Funakoshi, and K. Nishi- A. Nakashima, T. Sakurai, K. Inui, and S Studies on chromoproteins in Japanese bori Araki nori, Porphyra tenera. V. on the sugar Identification of volatile components of The occurrence and properties of 5’-AMP components of phycoerythrin. roasted laver by GC-MS analysis deaminase in dried and toasted nori J. Biochem., 49, 361-367 (1961). Bulletin of the Japanese Society of Scientif- Fisheries Science 66, 110–116 (2000). I. Goni, L. Valdivieso, and A. Garcia‐Alon- ic Fcisheries 52,751-754 (1986). H. Noda, H. Amano, K. Arashima, S. so K. Kasahara, and K. Nishibori Hashimoto, and K. Nishizawa Nori seaweed consumption modifies glyce- Flavoring volatiles of roasted laver-I Antitumour activity of polysaccharides mic response in healthy volunteers. Bulletin of the Japanese Society of Scientif- and lipids from marine algae. Nutrition Research, 20, 1367-1375 ic Fisheries 41, 193-199 (1975). Nippon Suisan Gakkaishi, 55, 1265-1271 (2000). M. Kayama, N. Iijima, M. Kuwahara, T. (1989). Y. Hama, H. Nakagawa, M. Kurosawa, T. Sado, S. Araki, and T. Sakurai Y. Osumi, K. Harada, N. Fukuda, H. Ama- Sumi, X. Xia, H. Hatate Effect of water temperature on the fatty no, and H. Noda A gas chromatographic method for the acid composition of Porphyra. Changes of volatile sulfur compounds of sugar analysis of 3,6-anhydrogalac- Bulletin of the Japanese Society of Scientif- ‘Nori’, Porphyra spp. during storage tose-containing algal galactans. ic Fisheries, 51, 687-691 (1985). Nippon Suisan Gakkaishi 56, 599-605 Analytical Biochemistry 265, 42-48 Y. Kitano, K. Murazumi, J. Duan, K. (1990). (1998). Kurose, S. Kobayashi, T. Sugawara and C. Oyamada, M. Kaneniwa, K. Ebitani, K. Harada, Y. Osumi, N. Fukuda, H. Ama- T. Hirata M. Murata, and K. Ishihara no, and H. Noda Effect of dietary porphyran from the red Mycosporine-like amino acids extracted Changes of amino acid compositions of alga, Porphyra yezoensis, on glucose from scallop (Patinopecten yessoen- ‘Nori’ products, Porphyra spp. during metabolism in diabetic KK-Ay mice. sis) ovaries: UV Protection and Growth storage. Journal of Nutritional Science and Vita- Stimulation Activities on Human Cells. Nippon Suisan Gakkaishi 56, 607-612 minology, 58, 14-19 (2012). Marine Biotechnology, 10, 141-150 (1990). R. Kohen, Y. Yamamoto, K. C. Cundy, and (2008). Y. Hiraoka, Y. Sasaki, and K. Sonoda B. N. Ames R. H. Reed Investigation of Contents of Nitrogenous Antioxidant activity of carnosine, homo- Osmoacclimation in Bangia atropurpurea Constituents in the Extracts of seafood carnosine, and anserine present in mus- (Rhodophyta, Bangiales): the osmotic caught in Ehime (Part1) (in Japanese). cle and brain. role of floridoside. Ehime Prefectural Industrial Technolo- Proc. Natl. Acad. Sci. USA., 85, 3175-9 British Phycological Journal, 20, 211-218 gy Research Institute report, 48, 19-22 (1988). (1985). (2011). D. Kubomura, Y. Matahira, A. Masui, and M. Saito, and H. Hagino S. Isaka, K. Cho, S. Nakazono, R. Abu, M. H. Matsuda Antihypertensive effect of oligopeptides Ueno, D. Kim, and T. Oda Intestinal absorption and blood clearance derived from Nori (Porphyra yezoensis) Antioxidant and anti-inflammatory activ- of L-histidine-related compounds after and Ala-Lys-Tyr-Ser-Tyr in rats. ities of porphyran isolated from discol- ingestion of anserine in humans and Journal of Japanese Society of Nutrition ored nori (Porphyra yezoensis). comparison to anserine- containing di- and Food Science 58, 177-184 (2005). International Journal of Biological Macro- ets., B. Soni, N. P. Visavadiya, and D. Madam- molecules, 74, 68-75 (2015). J. Agric. Food. Chem., 57, 1781-1785 war

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Ameliorative action of cyanobacterial phy- S. Tsuyama, Y. Nakano Sumi, H. Tachibana, and K. Yamada coerythrin on CCl4-induced toxicity in Feeding dried purple laver (nori) to vita- Dietary effect of porphyran from Porphyra

rats. min B12-deficient rats significantly im- yezoensis on growth and lipid metabo-

Toxicology, 248, 59-65 (2008). proves vitamin B12 status. lism of Sprague-Dawley rats. B. Soni, N. P. Visavadiya, and D. Madam- British Journal of Nutrition, 85, 699-703 Food Science and Technology Research, war (2001). 10, 147–151 (2004). Attenuation of diabetic complications by Y. Tamura, S. Takenaka, S. Sugiyama, and Y. Yabuta, H. Fujimura, C. Shilkwak, T. C-phycoerythrin in rats. R. Nakayama Enomoto, and F. Watanabe British Journal of Nutrition, 102, 102-109 Occurrence of anserine as an antioxida- Antioxidant Activity of the Phycoerythro- (2009). tive dipeptide in a red alga, Porphyra bilin Compound Formed from a Dried K. Suetsuna yezoensis. Korean Purple Laver (Porphyra sp.) Purification and identification of angio- Bioscience, Biotechnology, and Biochemis- during in Vitro Digestion tensin I-converting enzyme inhibitors try, 62, 561-563 (1998). Food Science and Technology Research, from the red alga Porphyra yezoensis. C. Tao, T. Sugawara, S. Maeda, X. Wang, 16, 347-351 (2010). Journal of marine biotechnology 6, 163- and T. Hirata T. Yoshida and P. M. Sivalingam 167 (1998). Antioxidative activities of a mycospo- Isolation and characterization of the H. Suzuki rine-like amino acid, porphyra-334 337mµ UV-absorbing substance in red Serum vitamin B12 levels in young vegans Fisheries Science, 74, 1166–1172 (2008). alga, Porphyra yezoensis UEDA who eat brown rice. K. Tsuchiya, S. Matsuda, G. Hirakawa, O. Plant & Cell Physiol., 11, 427-434 (1970). J. Nutr. Sci. Vitaminol., 41, 5877-594 Shimada, R. Horio, C. Taniguchi, T. Fu- Q. Zhang, N. Li, X. Liu, Z. Zhao, Z. Li, and (1995). jii, A. Ishida, and M. Iwahara Z. Xu S. Takano, D. Uemura, and Y. Hirata GABA production from discolored laver The structure of a sulfated galactan from Isolation and structure of a 334 nm UV by lactic acid fermentation and physio- Porphyra haitanensis and its in vivo an- absorbing substance, porphyra-334 from logical function of fermented laver. (In tioxidant activity. the red algae Porphyra tenera Kjellman. Japanese) Carbohydrate Research, 339, 105-111 Chemistry Letters 26, 419–420 (1979). Food preservation science, 33, 121-125 (2004). S. Takenaka, S. Sugiyama, E. Ebara, K. Mi- (2007). yamoto, Y. Abe, F. Tamura, S. Watanabe, K. Tsuge, M. Okabe, T. Yoshimura, T.

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