Skip to main content
Log in

Chemical structure and physico-chemical properties of agar

  • Agars and utilization
  • Published:
Hydrobiologia Aims and scope Submit manuscript

Abstract

Advances in the chemistry and physico-chemical properties of agar since the review of Araki at the Fifth International Seaweed Symposium in 1965 are discussed. These advances are essentially the result of better separation techniques of the heterogeneous family of polysaccharides known as agar, the use of nuclear magnetic resonance spectroscopy, the use of agarases and, particularly, the use of combinations of the three approaches. Although physico-chemical methods have evolved, particularly molecular-weight determinations, X-ray diffraction data and molecular modelling of agar, correlations between chemical and functional properties of agar and agarose and their gelation mechanisms remain to be studied.

This is a preview of subscription content, log in via an institution to check access.

Access this article

Price excludes VAT (USA)
Tax calculation will be finalised during checkout.

Instant access to the full article PDF.

Similar content being viewed by others

References

  • Aoki, T., T. Araki & M. Kitamikado, 1990. Purification and characterization of a novel β-agarase from Vibrio sp. AP-2. Eur. J. Biochem. 187: 461–465.

    Google Scholar 

  • Araki, C., 1937. Chemical studies of agar-agar. III. Acetylation of agar-like substance of Gelidium amansii. J. Chem. Soc. Japan 58: 1338–1350.

    Google Scholar 

  • Araki, C., 1966. Some recent studies on the polysaccharides of agarophytes. Proc. int. Seaweed Symp. 5: 3–17.

    Google Scholar 

  • Araki, C. & K. Arai, 1956). The chemical constitution of agar-agar. XVIII. Isolation of a new crystalline disaccharide by enzymatic hydrolysis of agar-agar. Bull. Chem. Soc. Japan 29: 339–345.

    Google Scholar 

  • Araki, C. & K. Arai, 1957. The chemical constitution of agar-agar. XX. Isolation of a tetrasaccharide by enzymatic hydrolysis of agar-agar. Bull. Chem. Soc. Japan 30: 287–293.

    Google Scholar 

  • Araki, C., K. Arai & S. Hirase, 1967. Studies on the chemical constitution of agar-agar. XXIII. Isolation of D-xylose, 6-O-methyl-D-galactose, 4-O-methyl-L-galactose and O-methylpentose. Bull. Chem. Soc. Japan 40: 959–962.

    Google Scholar 

  • Arnott, S., A. Fulmer, W. E. Scott, I. C. M. Dea, R. Moorhouse & D. A. Rees, 1974. Agarose double helix and its function in agarose gel structure. J. Mol. Biol. 90: 269–284.

    Google Scholar 

  • Asare, O., 1980. Seasonal changes in sulphate and 3,6-anhydrogalactose content of phycocolloids from two red algae. Bot. Mar. 23: 595–598.

    Google Scholar 

  • Barbero, J. J., C. Bouffar-Roupe, C. Rochas & S. Perez, 1989. Modelling studies of solvent effects on the conformational stability of agarobiose and neoagarobiose and their relationship to agarose. Int. J. Biol. Macromol. 11: 265–272.

    Google Scholar 

  • Batey, J. F. & J. R. Turvey, 1975. The galactan sulfate of the red alga Polysiphonia lanosa. Carbohydr. Res. 43: 133–143.

    Google Scholar 

  • Bhattacharjee, S. S., W. Yaphe & G. K. Hamer, 1978. 13C N.m.r. spectroscopic analysis of agar, κ-carrageenan and ι-carrageenan. Carbohydr. Res. 60: C1–C3.

    Google Scholar 

  • Bhattacharjee, S. S., W. Yaphe & G. K. Hamer, 1979. Study of agar and carrageenan by 13C nuclear magnetic resonance spectroscopy. Proc. int. Seaweed Symp. 9: 379–385.

    Google Scholar 

  • Bird, C. J., R. J. Helleur, E. R. Hayes & J. McLachlan, 1987. Analytical pyrolysis as a taxonomic tool in Gracilaria (Rhodophyta: Gigartinales). Proc. int. Seaweed Symp. 12: 207–212.

    Google Scholar 

  • Bird, K. T., 1988. Agar production and quality from Gracilaria sp. strain G-16: Effects of environmental factors. Bot. Mar. 31: 33–39.

    Google Scholar 

  • Bird, K. T., M. D. Hanisak & J. Ryther, 1981. Chemical quality and production of agars extracted from Gracilaria tikvahiae grown in different nitrogen enrichment conditions. Bot. Mar. 24: 441–444.

    Google Scholar 

  • Bowker, C. M. & J. R. Turvey, 1968. Water-soluble polysaccharides of the red alga Laurencia pinnatifida. Part I. Constituents units. J. Chem. Soc. C: 983–988.

  • Brasch, D. J., C. T. Chuah & L. D. Melton, 1981. A 13C N.M.R. study on some agar-related polysaccharides from New Zealand seaweeds. Austr. J. Chem. 34: 1095–1105.

    Google Scholar 

  • Chiles, T. C., K. T. Bird & F. E. Koehn, 1989. Influence of nitrogen availability on agar-polysaccharides from Gracilaria verrucosa strain G-16: structural analysis by NMR spectroscopy. J. Appl. Phycol. 1: 53–58.

    Google Scholar 

  • Christiaen, D. & M. Bodard, 1983. Spectroscopie infrarouge de films d'agar de Gracilaria verrucosa (Huds.) Papenfuss. Bot. mar. 26: 425–427.

    Google Scholar 

  • Christiaen, D., T. Stadler, M. Ondarza & M. C. Verdus, 1987. Structures and functions of the polysaccharides from the cell wall of Gracilaria verrucosa (Rhodophycae, Gigartinales). Proc. int. Seaweed Symp. 12: 139–146.

    Google Scholar 

  • Craigie, J. S. & A. Jurgens, 1989. Structure of agars from Gracilaria tikvahiae Rhodophyta: location of 4-O-methyl-L-galactose and sulfate. Carbohydr. Polymers 11: 265–278.

    Google Scholar 

  • Craigie, J. S. & Z. C. Wen, 1984. Effects of temperature and tissue age on gel strength and composition of agar from Gracilaria tikvahiae (Rhodophyceae). Can. J. Bot. 62: 1665–1670.

    Google Scholar 

  • Craigie, J. S., Z. C. Wen & J. P. van der Meer, 1984. Interspecific, intraspecific and nutritionally-determined variations in the compositions of agars from Gracilaria spp. Bot. mar. 27: 55–61.

    Google Scholar 

  • Djabourov, M., A. H. Clark, D. W. Rowlands & S. B. Ross-Murphy, 1989. Small-angle X-ray scattering characterization of agarose sols and gels. Macromolecules 22: 180–188.

    Google Scholar 

  • Doty, M. & G. A. Santos, 1983. Agar from Gracilaria cylindrica. Aquatic Bot. 15: 299–306.

    Google Scholar 

  • Duckworth, M., K. C. Hong & W. Yaphe, 1971. The agar polysaccharides of Gracilaria species. Carbohydr. Res. 18: 1–9.

    Google Scholar 

  • Duckworth, M. & J. R. Turvey, 1969a. An extracellular agarase from a Cytophaga species. Biochem. J. 113: 139–142.

    Google Scholar 

  • Duckworth, M. & J. R. Turvey, 1969b. The action of a bacterial agarase on agarose, porphyran and alkali-treated porphyran. Biochem. J. 113: 687–692.

    Google Scholar 

  • Duckworth, M. & W. Yaphe, 1971a. Preparation of agarose by fractionation from the spectrum of polysaccharides in agar. Anal. Chem. 44: 636–641.

    Google Scholar 

  • Duckworth, M. & W. Yaphe, 1971b. The structure of agar. Part I. Fractionation of a complex mixture of polysaccharides. Carbohydr. Res. 16: 189–197.

    Google Scholar 

  • Duckworth, M. & W. Yaphe, 1971c. The structure of agar. Part II. The use of a bacterial agarase to elucidate structural features of the charged polysaccharides in agar. Carbohydr. Res. 16: 435–445.

    Google Scholar 

  • Duraitnam, M. & N. Q. Santos, 1981. Agar from Gracilaria verrucosa (Hudson) Papenfuss and Gracilaria sjoestedtii Kylin from northeast Brazil. Proc. int. Seaweed Symp. 10: 669–674.

    Google Scholar 

  • Foord, S. A. & E. D. T. Atkins, 1989. New X-ray diffraction results from agarose: Extended single helix structure and implications for gelation mechanism. Biopolymers 28: 1345–1365.

    Google Scholar 

  • Friedlander, M., Y. Lipkin & W. Yaphe, 1981. Composition of agars from Gracilaria cf. verrucosa and Pterocladia capillacea. Bot. Mar. 24: 595–598.

    Google Scholar 

  • Furneaux, R. H., I. J. Miller & T. T. Stevenson, 1990. Agaroids from New Zealand members of the Gracilariaceae. A novel dimethylated agar. Hydrobiologia 204/205: 454–654.

    Google Scholar 

  • Guerin, J. M. & K. T. Bird, 1987. Effects of aeration period on the productivity and agar quality of Gracilaria sp. Aquaculture 64: 105–110.

    Google Scholar 

  • Groleau. D. & W. Yaphe, 1977. Enzymatic hydrolysis of agar: purification and characterization of β-neoagarote-traose-hydrolase from Pseudomonas atlantica. Can. J. Microbiol. 23: 672–679.

    Google Scholar 

  • Guiseley, K. B., 1970. The relationship between methoxy content and gelling temperature of agarose. Carbohydr. Res. 13: 247–256.

    Google Scholar 

  • Guiseley, K. B., 1987. Natural and synthetic derivatives of agarose and their use in biochemical separations. In M. Yalpani (ed.) Industrial Polysaccharides: Genetic Engineering, Structure/Property Relations and Applications. Elsevier Science Publishers B.V., Amsterdam, 139–147.

    Google Scholar 

  • Hamer, G. K., S. S. Bhattacharjee & W. Yaphe, 1977. Analysis of the enzymatic hydrolysis products of agarose by 13C-n.m.r. spectroscopy. Carbohydr. Res. 54: C7–C10.

    Google Scholar 

  • Helleur, R. J., E. R. Hayes, J. S. Craigie & J. L. McLachlan, 1985a. Characterization of polysaccharides of red algae by pyrolysis-capillary gas chromatography. J. Anal. appl. Pyr. 8: 349–357.

    Google Scholar 

  • Helleur, R. J., E. R. Hayes, W. D. Jamieson & J. S. Craigie, 1985b. Analysis of polysaccharide pyrolysate of red algae by capillarly gas chromatography-mass spectrometry. J. Anal. appl. Pyrolysis 8: 333–347.

    Google Scholar 

  • Hirase, S., 1957. Studies on the chemical constitution of agar-agar. XIX. Pyruvic acid as a constituent of agar-agar (Part 3). Structure of the pyruvic acid-linking disaccharide derivative isolated from methanolysis products of agar. Bull. Chem. Soc. Japan 30: 75–79.

    Google Scholar 

  • Hirase, S. & C. Araki, 1961. Isolation of 6-O-methyl-D-galactose from the agar of Ceramium boydenii. Bull. Chem. Soc. Japan 34: 1048.

    Google Scholar 

  • Hirase, S. & K. Watanabe, 1971. Fractionation and structural investigation of funoran. Proc. int. Seaweed Symp. 7: 451–454.

    Google Scholar 

  • Hong, K. C., M. E. Goldstein & W. Yaphe, 1969. A chemical and enzymic analysis of the polysaccharides from Gracilaria. Proc. int. Seaweed Symp. 6: 473–482.

    Google Scholar 

  • Hoyle, M., 1978a. Agar studies in two Gracilaria species (G. bursapastoris (Gmelin) Silva and G. coronopifolia. Ag.) from Hawaii. I. Yield and gel strength in the gametophyte and tetrasporophyte generations. Bot. mar. 21: 343–345.

    Google Scholar 

  • Hoyle, M., 1978b. Agar studies in two Gracilaria species (G. bursapastoris (Gmelin) Silva and G. coronopifolia. Ag.) from Hawaii. II. Seasonal Aspects. Bot. mar. 21: 347–352.

    Google Scholar 

  • Izumi, K., 1970. A new method for fractionation of agar. Agr. Biol. Chem. 34: 1739–1740.

    Google Scholar 

  • Izumi, K., 1971. Chemical heterogeneity of the agar from Gelidium amansii. Carbohydr. Res. 17: 227–230.

    Google Scholar 

  • Izumi, K., 1972. Chemical heterogeneity of the agar from Gracilaria verrucosa. J. Biochem. 72: 135–140.

    Google Scholar 

  • Izumi, K., 1973. Structural analysis of agar-type polysaccharides by NMR spectroscopy. Biochim. Biophys. Acta 320: 311–317.

    Google Scholar 

  • Ji, M., M. Lahaye & W. Yaphe, 1985. Structure of agar from Gracilaria spp. (Rhodophyta) collected in People's Republic of China. Bot. mar. 28: 521–528.

    Google Scholar 

  • Ji, M., M. Lahaye & W. Yaphe, 1988. Structural studies on agar fractions extracted sequentially from Chinese red seaweeds: Gracilaria sjeostedtii, G. textorii and G. salicornia using 13C-NMR and IR spectroscopy. Chin. J. Oceanol. Limnol. 6: 87–103.

    Google Scholar 

  • John, D. M. & S. O. Asare, 1975. A preliminary study of the variations in yield and properties of phycocolloids from Ghanaian seaweeds. Mar. Biol. 30: 325–330.

    Google Scholar 

  • Karamanos, Y., M. Ondarza, F. Bellanger, D. Christiaen & S. Moreau, 1989. The linkage of 4-O-methyl-L-galactopyranose in the agar polymers from Gracilaria verrucosa. Carbohydr. Res. 187: 93–101.

    Google Scholar 

  • Kim, D. H. & N. P. Henriquez, 1978. Yields and gel strengths of agar from cystocarpic and tetrasporic plants of Gracilaria verrucosa (Florideophyceae). Proc. int. Seaweed Symp. 9: 257–262.

    Google Scholar 

  • Kim, C. S. & H. J. Humm, 1965. The red alga, Gracilaria foliifera with special reference to the cell wall polysaccharides. Bull. Mar. Sci. 15: 1036–1050.

    Google Scholar 

  • Lahaye, M., 1986. Agar from Gracilaria spp. PhD Thesis, McGill University, Montréal, Québec, Canada: pp 330.

    Google Scholar 

  • Lahaye, M., J. F. Revol, C. Rochas, J. McLachlan & W. Yaphe, 1988. The chemical structure of Gracilaria crassissima (P. & H. Crouan in Schramm & Mazé) P. & H. Crouan in Schramm & Mazé and G. tikvahiae McLachlan (Gigartinales, Rhodophyta) cell-wall polysaccharides. Bot. mar. 31: 491–501.

    Google Scholar 

  • Lahaye, M., C. Rochans & W. Yaphe, 1986. A new procedure for determining the heterogeneity of agar polymers in the cell walls of Gracilaria spp. (Gracilariaceae, Rhodophyta). Can. J. Bot. 64: 579–585.

    Google Scholar 

  • Lahaye, M. & W. Yaphe, 1988. Effects of seasons on the chemical structure and gel strength of Gracilaria pseudoverrucosa agar (Gracilariaceae, Rhodophyta). Carbohydr. Polymers 8: 285–301.

    Google Scholar 

  • Lahaye, M. & W. Yaphe, 1989. The chemical structure of agar from Gracilaria compressa (C. Agardh) Greville, G. cervicornis (Turner) J. Agardh, G. damaecornis J. Agardh and G. domingensis Sonder ex Kützing (Gigartinales, Rhodophyta). Bot. Mar. 32: 369–377.

    Google Scholar 

  • Lahaye, M., W. Yaphe, M. T. Phan Viet & C. Rochas, 1989. 13C-N.M.R. spectroscopic investigation of methylated and charged agarose oligosaccharides and polysaccharides. Carbohydr. Res. 190: 249–265.

    Google Scholar 

  • Lahaye, M., W. Yaphe & C. Rochas, 1985. 13C-N.m.r. spectral analysis of sulfated and desulfated polysaccharides of the agar type. Carbohydr. Res. 143: 240–245.

    Google Scholar 

  • Lignell, Å. & M. Pedersén, 1989. Agar composition as a function of morphology and growth rate. Studies on some morphological strains of Gracilaria secundata and Gracilaria verrucosa (Rhodophyta). Bot. Mar. 32: 219–227.

    Google Scholar 

  • Matsuhashi, T. & K. Hayashi, 1971. Rheological behavior of agar gels processed from Gracilaria foliifera of Florida. Proc. Int. Seaweed Symp. 7: 464–468.

    Google Scholar 

  • Matsuhiro, B. & C. C. Urzúa, 1991. Agars from Chilean Gelidiaceae. Hydrobiologia 221: 149–156.

    Google Scholar 

  • McCandless, E. L., 1981. Polysaccharides of the Seaweeds. In Lobban, C. S. & M. J. Wynne (eds.) The Biology of Seaweeds. Blackwell Scientific Publications: pp. 559–588.

  • Meer, W., 1980. In Davidson, R. S. (ed.) Handbook of Water Soluble Gums and Resins. McGraw Hill, 7: 17–19.

  • Miller, I. J., H. Wong & R. H. Newman, 1982. A carbon-13 NMR study of some disaccharides from algal polysaccharides. Austr. J. Chem. 35: 853–856.

    Google Scholar 

  • Morice, L. M., M. W. McLean, F. B. Williamson & W. F. Long, 1983a. β-agarase I and II from Pseudomonas atlantica. Purifications and some properties. Eur. J. Biochem. 135: 553–558.

    Google Scholar 

  • Morrice, L. M., M. W. McLean, W. F. Long & F. B. Williamson, 1983b. Prophyran primary structure. An investigation using β-agarase I from Pseudomonas atlantica and 13C-NMR spectroscopy. Eur. J. Biochem. 133: 673–684.

    Google Scholar 

  • Nelson, S. G., S. S. Yang, C. Y. Yang & Y. M. Chiang, 1983. Yield and quality of agar from species of Gracilaria (Rhodophyta) collected from Taiwan and Micronesia. Bot. mar. 26: 361–366.

    Google Scholar 

  • Nicolaissen, F. M., I. Meyland & K. Schaumburg, 1980. 13C NMR spectra at 67.9 MHz of agarose solutions and partly 6-O-methylated agarose at 95 °C. Acta Chem. Scand. Ser. B 34: 103–107.

    Google Scholar 

  • Ondarza, M., Y. Karamanos, D. Christiaen & T. Stadler, 1987. Variations in the composition of agar polysaccharides from Gracilaria verrucosa, cultivated under controlled conditions. Food Hydrocolloids 5/6: 507–509.

    Google Scholar 

  • Onraët, A. C. & B. L. Robertson, 1987. Seasonal variation in yield and properties of agar from sporophytic and gametophytic phases of Onikusa pristoides (Turner) Akatsuka (Gelidiaceae, Rhodophyta). Bot. mar. 30: 491–495.

    Google Scholar 

  • Oza, R. M., 1978. Studies on Indian Gracilaria. IV. Seasonal variation in agar and gel strength of Gracilaria corticata J. Ag. occurring on the coats of Veraval. Bot. mar. 21: 165–167.

    Google Scholar 

  • Patwary, M. U. & J. P. van der Meer, 1983. Genetics of Gracilaria tikvahiae (Rhodophyceae) IX: Some properties of agars extracted from morphological mutants. Bot. mar. 26: 295–299.

    Google Scholar 

  • Peat, S., J. R. Turvey & D. A. Rees, 1961. Carbohydrate of the red alga, Porphyra umbillicalis. J. Chem. Soc.: 1590–1595.

  • Rees, D. A., 1961a. Enzymatic synthesis of the 3,6-anhydro-L-galactose with porphyran from L-galactose 6-sulphate units. Biochem. J. 81: 347–352.

    Google Scholar 

  • Rees, D. A., 1961b. Estimation of the relative amounts of isomeric sulphate esters in some sulphated polysaccharides. J. Chem. Soc.: 5168–6171.

  • Rees, D. A., 1969. Structural, conformation and mechanism in the formation of polysaccharide gels and networks. Adv. Carbohydr. Chem. Biochem. 24: 267–332.

    Google Scholar 

  • Rees, D. A. & E. Conway, 1962. The structure and biosynthesis of porphyran: a comparison of some samples. Biochem. J. 84: 411–416.

    Google Scholar 

  • Rees, D. A. & E. J. Welsh, 1977. Secondary and tertiary structure of polysaccharides in solution and gels. Angew. Chem. Int. Ed. Eng. 16: 214–224.

    Google Scholar 

  • Rochas, C. & M. Lahaye, 1989a. Average molecular weight and molecular weight distribution of agarose and agarose-type polysaccharides. Carbohydr. Polymers 10: 289–298.

    Google Scholar 

  • Rochas, C. & M. Lahaye, 1989b. Solid state 13C-NMR spectroscopy of red Seaweeds, agars and carrageenans. Carbohydr. Polymers 10: 189–204.

    Google Scholar 

  • Rochas, C., M. Lahaye & W. Yaphe, 1986a. Sulfate content of carrageenan and agar determined by infrared spectroscopy. Bot. mar. 29: 335–340.

    Google Scholar 

  • Rochas, C., M. Lahaye, W. Yaphe & M. T. Phan Viet, 1986b. 13C NMR-spectroscopic investigation of agarose oligomers. Carbohydr. Res. 148: 199–207.

    Google Scholar 

  • Rochas, C., M. Rinaudo & S. Landry, 1990. Role of molecular weight on the mechanical properties of kappa-carrageenans gels. Carbohydr. Polymers 12: 255–266.

    Google Scholar 

  • Samec, M. von, & V. Isajevic, 1922. Studien uber pipanzen kolloide. XIV. Physico-chemische analyse der agargallerte. Kolloidchem. Beih. 16: 285–300.

    Google Scholar 

  • Shashkov, A. S., A. I. Usov & S. V. Yarotskii, 1978. Polysaccharides of algae. XXIV. The application of 13C NMR spectroscopy to the analysis of the structure of polysaccharides of the agar group. Bioorg. Khim. 4: 74–81 (in Russian).

    Google Scholar 

  • Sheng, S. Y., Z. Y. Xia, L. Z. En & L. W. Qing, 1984. The yield and properties of agar extracted from different life stages of Gracilaria verrucosa. Proc. int. Seaweed Symp. 11: 551–553.

    Google Scholar 

  • Smidsrod, O., 1974. Molecular basis for some physical properties of alginates in the gel state. Faraday Dis. Chem. Soc. 57: 263–274.

    Google Scholar 

  • Stevenson, T. T. & R. H. Furneaux, 1991. Chemical methods for the analysis of sulphated galactans from red algae. Carbohydr. Res. (in press).

  • Turvey, J. R. & J. Christison, 1967a. The hydrolysis of algal galactans by enzymes from a Cytophaga species. Biochem. J. 105: 311–316.

    Google Scholar 

  • Turvey, J. R. & J. Christison, 1967b. The enzymic degradation of porphyran. Biochem. J. 105: 317–321.

    Google Scholar 

  • Turvey, J. R. & E. L. Williams, 1976. The agar-type polysaccharide from the red alga Ceramium rubrum. Carbohydr. Res. 49: 419–425.

    Google Scholar 

  • Usov, A. I., 1984. NMR spectroscopy of red seaweed polysaccharides: Agars, carrageenans, and xylans. Bot. mar. 27: 189–202.

    Google Scholar 

  • Usov, A. I. & E. G. Ivanova, 1981. Polysaccharides of algae. XXXI: Enzymatic cleavage of an agar-like polysaccharide from the red alga Rhodomela larix (Turn.) C. Ag. Bioorg. Khim. 7: 1060–1068 (in Russian).

    Google Scholar 

  • Usov, A. I. & E. G. Ivanova, 1987. Polysaccharides of algae. XXXVII. Characterization of hybrid structure of substituted agarose from Polysiphonia morrowii (Rhodophyta, Rhodomelaceae) using β-agarase and 13C-NMR spectroscopy. Bot. mar. 30: 365–370.

    Google Scholar 

  • Usov, A. I., E. G. Ivanova & V. F. Makienko, 1989. Polysaccharides of algae. XXIX: Comparison of samples of agar from different generations of Gracilaria verrucosa (Huds.) Papenf. Bioorg. Khim. 5: 1647–1653 (in Russian).

    Google Scholar 

  • Usov, A. I., E. G. Ivanova & A. S. Shashkov, 1983. Polysaccharides of algae. XXXIII: Isolation and 13C NMR spectral study of some new gel-forming polysaccharides from Japan Sea red seaweeds. Bot. mar. 26: 285–294.

    Google Scholar 

  • Usov, A. I., L. I. Miroshnikova, 1975. Isolation of agarase from Littorina mandshurica by affinity chromatography on Biogel A. Carbohydr. Res. 43: 204–207.

    Google Scholar 

  • Usov, A. I., S. V. Yarotsky & A. S. Shashkov, 1980. 13C NMR spectroscopy of red algal galactans. Biopolymers 19: 977–990.

    Google Scholar 

  • Watase, M. & K. Nishinari, 1981a. Effect of alkali metal ions on the rheological properties of κ-carrageenan and agarose gels. J. Text. Stud. 12: 427–445.

    Google Scholar 

  • Watase, M. & K. Nishinari, 1981b. Effect of sodium hydroxide pretreatment on the relaxation spectrum of concentrated agar-agar gels. Rheol. Acta 20: 155–162.

    Google Scholar 

  • Watase, M. & K. Nishinari, 1982. Effect of alkali metal ions on the viscoelasticity of concentrated kappa-carrageenan and agarose gels. Rheol. Acta 21: 318–324.

    Google Scholar 

  • Welti, D., 1977. The 300 MHz proton magnetic resonance spectra of methyl β-D-galactopyranoside, methyl 3,6-anhydro-α-D-galactopyranoside, agarose, κ-carrageenan, and segments of ι-carrageenan and agarose sulphate. J. Chem. Res. (S): 312–313, (M): 3566–3587.

  • Wen, Z. C. & J. S. Craigie, 1984. Composition and properties of agar-type polysaccharides from Gracilaria sjoestedtii Kylin. Chin. J. Oceanol. Limnol. 2: 88–91.

    Google Scholar 

  • Whyte, J. N. C. & J. R. Englar, 1981. The agar component of the red seaweed Gelidium purpurascens. Phytochem. 20: 237–240.

    Google Scholar 

  • Whyte, J. N. C., J. R. Englar, R. G. Saunders & J. C. Lindsay, 1981. Seasonal variations in the biomass, quantity and quality of agar from the reproductive and vegetative stages of Gracilaria (verrucossa type). Bot. mar. 24: 493–501.

    Google Scholar 

  • Whyte, J. N. C., S. P. C. Hosford & J. R. Englar, 1985. Assignment of agar or carrageenan structures to red algal polysaccharides. Carbohydr. Res. 140: 336–341.

    Google Scholar 

  • Yanagawa, T., 1946. Kanten (Agar), 2nd edn (in Japanese), Sangiotosho Co. LTD Tokyo., Japan: 352 pp.

    Google Scholar 

  • Yang, S. S., C. H. Yang & H. H. Wang, 1981. Seasonal variation of agar-agar produced in Taiwan area. Proc. int. Seaweed Symp. 10: 737–742.

    Google Scholar 

  • Yaphe, W., 1957. The use of agarase from Pseudomonas atlantica in the identification of agar in marine algae (Rhodophyceae). Can. J. Microbiol. 3: 987–993.

    Google Scholar 

  • Young, K. S., S. S. Battacharjee & W. Yaphe, 1978. Enzymic cleavage of the α-linkages in agarose to yield agarooligosaccharides. Carbohydr. Res. 66: 207–212.

    Google Scholar 

  • Young, K. S., M. Duckworth & W. Yaphe, 1971. The structure of agar. Part III. Pyruvic acid, a common feature of agars from different agarophytes. Carbohydr. Res. 16: 446–448.

    Google Scholar 

Download references

Author information

Authors and Affiliations

Authors

Rights and permissions

Reprints and permissions

About this article

Cite this article

Lahaye, M., Rochas, C. Chemical structure and physico-chemical properties of agar. Hydrobiologia 221, 137–148 (1991). https://doi.org/10.1007/BF00028370

Download citation

  • Issue Date:

  • DOI: https://doi.org/10.1007/BF00028370

Key words

Navigation