• The Korean Journal of Food And Nutrition
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• v.23 no.4
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• pp.562-569
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• 2010

This study was conducted to investigate the hypocholesterolemic effects of porphyran and insoluble dietary fiber isolated from laver in rats fed high fat diet containing 1% cholesterol, 0.25% sodium cholate and 12% lard. Rats were fed, ad libitum, diets containing 5% diet fiber as cellulose(normal control or high fat control), porphyran or insoluble dietary fiber for 4 weeks. Among the groups fed high fat diet, liver weight was significantly lower in high fat porphyran group than high fat control. Plasma GOT, GPT, total cholesterol, cholesteryl ester, LDL-cholesterol and liver total cholesterol concentration were significantly lower in high fat porphyran group than high fat control. The feeding of porphyran significantly increased fecal cholesterol and bile acid excretion. The feeding of insoluble dietary fiber had no significant effect on either plasma or liver cholesterol levels, although fecal cholesterol level in the insoluble dietary fiber group was significantly higher than that in the high fat control. The results indicate that porphyran isolated from the laver may exert their hypocholesterolemic effect by increasing excretion of fecal bile acid and cholesterol.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.48 no.1
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• pp.58-63
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• 2015

The chemical and rheological properties of natural and enzymatically hydrolyzed porphyran isolated from Pyropia yezoensis were investigated. The enzymatic hydrolysate was prepared by hydrolysis of porphyran using ${\beta}$-agarase followed by fractionation based on molecular weight (>300 kDa (Fr-1), 100-300 kDa (Fr-2), 10-100 kDa (Fr-3) and 1-10 kDa (Fr-4) using an ultrafiltration membrane. Each hydrolysate fraction consisted mainly of galactose (42.7-57.5%), 3,6-anhydro galactose (6.5-15.1%) and ester sulfate (8.6-14.1%). The sulfate content of the enzymatically hydrolyzed fractions decreased with an increase in molecular weight, whereas the 3,6-anhydro galactose content increased significantly. The rheological behavior of porphyran and enzymatically hydrolyzed porphyran solutions demonstrated a pseudoplastic behavior, which agrees with the Herschel-Bulkley model. The effect of temperature on the viscosity of the porphyrans and hydolysate fractions were measured and modeled using the Arrhenius equation. The activation energy of the porphyrans and enzymatically hydrolyzed porphyran (Fr-1) increased from 12.30 to 20.29 kJ/mol and 9.06 to 23.84 kJ/mol, respectively with increasing concentrations from 3% to 7%. These data indicate that the extent of the apparent viscosity of porphyran and enzymatically hydrolyzed porphyran are influenced by both temperature and concentration.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.31 no.1
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• pp.127-131
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• 1998

The effect of extraction temperature ($60\~100^{\circ}C$) and pH ($2.0\~13.5$) on the yield and chemical compositions of crude porphyran from Porphyra Yezoensis was investigated. The yield and chemical compositions of crude porphyran were greatly affected by extraction pH and temperature. Yield was highest between pH $3\~4$ at all temperature ranges. Crude porphyran extracted in acidic conditions showed more sulfate and less protein content than extracted in neutral conditions, but molecular weights was decreased. Crude porphyran extracted in alkaline conditions showed low sulfate and high protein content. For high yield and low molecular weight, acidic condition, particulary pH $3\~4$, was effective. But in order to avoid molecular weight degradation, neutral conditions were effective.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.44 no.6
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• pp.630-634
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• 2011

Enzymatic hydrolysate of porphyran from Porphyra yezoensis was prepared by treatment with ${\beta}$-agarase. The hydrolysate was fractioned into molecular sizes of <3, 3-30, and 30-300 kDa using an ultrafiltration membrane. The membrane fractions were further separated into neutral and anionic fractions using Dowex $1{\times}8$ ion exchange chromatography. After hydrolysis of porphyran with ${\beta}$-agarase, 23.2% of the starting porphyran was recovered as a neutral fraction of low-molecular weight (<3 kDa), and 28.9% remained as an enzyme-resistant anionic fraction of high molecular weight (>300 kDa). Desulfation of porphyran and $^{13}C$-NMR analysis of the anionic fraction of low molecular weight (<3 kDa) showed that the anionic fraction has a backbone consisting of 3-linked ${\beta}$-D-galactose units alternating with either 4-linked a-L-galactose 6-sulfate or 3, 6-anhydro-a-L-galactose units. These results indicate that porphryan is a copolymer of two moieties, about 25% of which are composed of neoagarose moieties and 75% as anionic moieties.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.40 no.1
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• pp.1-7
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• 2007

The chemical and rheological properties of deproteinated porphyrans from laver Porphyra yezoensis were investigated to obtain basic data for the production of food materials with biological functionality. Deproteinated porphyran was prepared by acid extraction (pH 4.0, $80^{\circ}C$, 4 hr) and successive hydrolysis with 0.5% Alcalase and 0.5% Flavourzyme. The porphyran constituted 10.7% of the dry laver and consisted of 0.6% protein, 14.8% ester sulfate, 3.2% 6-O-methyl galactose, 16.0% 3,6-anhydro-L-galactose, and 67.3% galactose. The effects of concentration and temperature on the apparent viscosity were examined by applying the power law and Arrhenius equations. The porphyran solution showed the typical behavior of a pseudoplastic liquid and the flow behavior index decreased with increasing concentration. The activation energy of the deproteinated porphyran solution at a 1,000 L/s shear rate also increased from $1.4954{\times}10^{4}\;to\;1.9544{\times}10^{4}\;J/kg$ mol with the concentration.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.41 no.6
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• pp.409-413
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• 2008

A simple method for the purification of porphyran from laver Porphyra yezoensis was developed to obtain information for the development of food materials with biological functionality. Crude porphyran (CP) was extracted from dried laver in boiling water for 3 h, and then fractionated using cetylpyridinium chloride into an acidic fraction (CP-F1) and a neutral fraction (CP-F2). CP-F1 was fractionated further by fractional ethanol precipitation. Fraction CP-F1-70, precipitated at an ethanol concentration of 61-70% was the major fraction containing 68.1% of the yield from the initial fraction CP-F1. The CP-F1-70 fraction displayed a single band on Sepharose CL-4B with a molecular mass of 550 kDa, indicating a homogeneous polysaccharide. The molar ratio of galactose, 3,6-anhydro-L-galactose, 6-0-methyl-D-galactose and ester sulfate of CP-F1-70 was 1:0.32:0.07:0.53. This method is very useful for rapid and large-scale preparation of purified porphyran because it is compatible with mass production.

• Journal of Fisheries and Marine Sciences Education
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• v.29 no.1
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• pp.108-117
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• 2017

Laver, Porphyra, is distinctive for its high content of proteins and polysaccharides such as porphyran and hemicellulose. The chemical properties of the polysaccharides extracted with different extraction methods such as hot water, dilute acid(pH 4.0) or alkali solution(2N NaOH) were examined to investigate the suitable extraction conditions for porphyran and hemicellulose from laver. For porphyran extraction, dilute acid solution was more preferable to hot water and alkali solution because of its higher 3,6-anhydrogalactose content and lower protein content. However, alkali solution was more suitable to extract the hemicellulose because of higher mannose content indicating the extraction of mannan. To decrease contamination of the polysaccharides with protein, the dried lavers were pretreated with enzymes (Protamex, Flavourzyme, Alcalase, Viscozyme) before hot water extraction. All enzyme pretreatments increased the yield of polysaccharides by compared with control (enzyme unpretreated) and Flavourzyme pretreatment was most effective to decrease protein contamination in the polysaccharide. All viscosities of porphyran solutions pretreated by enzymes were lower compared to the control porphyran solution and showed pseudoplastic behavior with yield stress. In case of alkali extraction of residues obtained after enzyme hydrolysis and hot water extraction, protease pretreatment increased the mannose contents in the polysaccharide while the xylose content was increased by Viscozyme pretreatment.

• Proceedings of the Korean Society of Fisheries Technology Conference
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• 2002.10a
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• pp.100-101
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• 2002

Red seaweeds contain considerable amounts of polysaccharides often having peculiar structures. The major soluble polysaccharide in Porphyra species is porphyran, which usually has a linear backbone composed of alternating 3-O-linked $\beta$-D-galactopyianose and 4-O-linked $\alpha$-L-galactopyranose(or 3,6 anhydro-L-galacto pyranose) residues. But the substituting patterns are very complex. (omitted)

• Proceedings of the Korean Society of Fisheries Technology Conference
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• 1995.06a
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• pp.276-277
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• 1995

• Proceedings of the Korean Society of Fisheries Technology Conference
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• 1996.06a
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• pp.202-203
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• 1996