Fucoxanthin content and antioxidant properties of Undaria pinnatifida

► First study to analyse fucoxanthin content and antioxidant activity of New Zealand Undaria. ► Identified seasonal variation of fucoxanthin content and antioxidant activity in Undaria. ► Compared fucoxanthin content and antioxidant activity between New Zealand and Japanese/Korean Undaria products. ► Found Relatively high fucoxanthin content in sporophyll, often considered as waste.