Species identification by SDS-PAGE of red algae used as seafood or a food ingredient

The identification, by SDS-PAGE, of four red algae used as sea vegetables or ingredients by the food industry, was performed. They were Palmaria palmata (Dulse), Chondrus crispus (Pioca), Porphyra umbilicalis (Nori), Gracilaria verrucosa (Ogo-nori). For each species, variations in protein patterns were observed, according to the season. However, for all species, some protein bands were always present during the yearly cycle of the plant. The reference pattern of P. palmata was composed of six protein bands with apparent molecular weights between 59.6 and 15.2 kDa. The G. verrucosa pattern was constituted of eight permanent bands. Two pattern bands, with apparent molecular weights of 49.1 and 45.9 kDa,differentiated the G. verrucosa profile from other seaweed patterns. C. crispus could be identified by a reference pattern composed of seven bands; three, with close molecular weights (49.3; 46.2 and 43.2 kDa), were characteristic of this species. Finally, the P. umbilicalis pattern showed seven bands with molecular weights between 73.1 and 15.9 kDa. The presence of a band with a molecular weight above 70 kDa appeared to be specific to the Porphyra pattern. So the SDS-PAGE seemed able to identify the four red species used by the food industry, but this analytical method appeared to be applicable only to raw material dried in mild conditions.