Mild hydrochloric acid hydrolysis of i-carrageenan from Eucheuma spinosum yielded two oligosaccharides of sulfated tetrasaccharide structure. These were characterized by Fourier Transform Infrared Spectroscopy (FT-IR), Nuclear Magnetic Resonance (NMR) and Electrospray Ionization Mass Spectrometry (ESIMS). Both oligosaccharides have structure of b-D-galactopyranose(Galp)4S-(1→4)-α-D-AnGalp2S-(1→3)-b-D-galactopyranose Galp)4S-(1→4)-α-D-AnGalp2S-(1→3). Application of the resulting oligosaccharides on protein delivery system in terms of encapsulation efficiency was performed.