Phycobiliproteins, nitrogenous compounds and fatty acid contents in field-collected and cultured gametophytes of Porphyra dioica, a red sea vegetable

The extensive variation in the biochemical composition of algal species is used as a source of potential bioactive compounds for applications in the agri-food industry and in the field of functional foods. Among these species, Porphyra/Pyropia spp. (nori, laver) are red sea vegetables which provide the foundation for a billion-dollar industry. In this study, we determine the growth and biochemical composition of distinct reproductive traits (females vs. males) in Porphyra dioica. In order to characterize and enhance through cultivation the bioactive profiles and biochemical composition of this sea vegetable, we determined the effects of environmental parameters (light and nutrients) on the growth of different life history traits (females vs. males) in cultured and field samples of P. dioica. In field-collected samples, females contained higher contents of phycoerythrin (9.71 ± 3.13 mg g−1 DW), PUFA (omega-3 fatty acids, 12.25 ± 0.78 mg g−1 DW; eicosapentaenoic acid, 11.54 ± 0.92 mg g−1 DW) and total fatty acids (TFA) (31.58 ± 2.5 mg g−1 DW) than males. The total nitrogen (TN) content was similar in both traits in the field, but the protein nitrogen (PN) was higher in males from field collections (42.80 mg g−1 DW). In culture, males and females responded differently to applied environmental factors, with an increase of some omega-6 fatty acids (e.g. 20:4 n-6 with an increase of 4.98 %TFA, 0.1 mg g−1 DW) in females and omega-7,9 fatty acids in males (increase of 13.75 %TFA, 0.79 mg g−1 DW in omega-7 and 1.59 %TFA in omega-9) associated with exposure to adverse conditions (N starvation under low light intensity). We discuss the possibility of using P. dioica as a promising source of functional new food products such as enriched nori in bioactive compounds such as monounsaturated and polyunsaturated fatty acids.

Department of Agriculture, Food and the Marine (Ireland) [13/F/536]