Cooking effects on chlorophyll profile of the main edible seaweeds

Edible seaweeds are rich in chlorophyll pigments, although their modifications during cooking remain unknown. Consequently, the three most consumed seaweeds of different categories: Nori (Porphyra umbilicales), Sea Lettuce (Ulva sp.) and Kombu (Laminaria ochroleuca) were subjected to two cooking processes, boiling and microwaving. The chemical reactions of the chlorophyll pigments were determined by HPLC-UV/Vis. Besides the main chlorophyll transformations already described in fruits and vegetables (pheophytinisation and decarboxymethylation), the cooking of seaweeds caused a high level of oxidative reactions. Statistically, Nori was the most resistant algae to heating, while Sea Lettuce was the most labile seaweed. We report the thermal stability of c series for the first time, which were significantly less stable than a series in Kombu. Differences after microwaving and boiling methods depend mainly on the seaweed class. In conclusion, the seaweed structure is the main factor that determines the influence of cooking on the chlorophyll profile.