The general objective of this study was to evaluate the stability of encapsulated pigment prepared from brown seaweed (Sargassum sp). A simple and rapid extraction procedure was employed to collect brown–algal photosynthetic pigments, followed by encapsulation using freeze drying with maltodextrin and Tween–80 as the encapsulating agents. The product showed yellowish green powdery pigments. Chromatography analysis confirmed the presence of trans–fucoxanthin as major carotenoid. Then, the stability of pigment in the freeze–dried powder during dark storage was studied at 28 °C, 45 °C, and 65 °C. The degradation of the surface of the encapsulated pigments was evaluated chromametrically by measuring the L*, a*, and b* values. Finally, the half–life of the encapsulated pigment was estimated.