Chemical composition of Porphyra spp. in British Columbia, Canada

Major chemical constituents and their seasonal changes were determined in several native Pacific Northwest species of Porphyra. The Porphyra samples collected at three different sites, Whiffin Spit (Sooke), Orlebar Pt. (Gabriola Island), and Wreck Beach (Vancouver), were P. torta Krishnamurthy, P. perforata J. Agardh, P. pseudolanceolata Krishnamurthy, P. mumfordii Lindstrom et Cole, and P. fallax Lindstrom et Cole.;Eicosapentaenoic acid, palmitic acid, floridosides, porphyran, ash content and dry weight showed significant but irregular fluctuations or seasonal changes over the growing period of Porphyra, which suggests the need for appropriate timing of harvest depending on the purpose of Porphyra utilization.;Total lipid content ranged from 0.10% to 1.70% (dw). The content of eicosapentaenoic acid, the major polyunsaturated fatty acid, varied from 0.01 mg g.;Total amino acid content of Porphyra in this study was relatively high, and ranged from 16.65% to 43.79% (dw). The composition of total amino acids was dominated by methionine, alanine, and tyrosine, in 1991, and alanine, arginine and glutamic acid in 1992. Slightly different composition was observed in free amino acids, which were dominated by alanine, threonine, and glutamic acid in both collection years.;The content of porphyran ranged from 7.63% to 55.59% (dw), isofloridoside, from 0.37% to 8.26% (dw), and floridoside, from 0.13% to 4.91% (dw). Ash content ranged from 12.23% to 26.30% (dw).;Significant variations among species were observed in all chemical contents analyzed, except isofloridoside. Moreover, significant inter-site variations were recorded for total amino acids and eicosapentaenoic acid content in P. perforata collected at Whiffin Spit and Orlebar Point.;In conclusion, this study confirms the feasibility of Porphyra harvest for a highly valued product based on its chemical constituents.