Background and Objective: Carrageenans can be found in a group of red algae called
Carrageenophytes (Gigartinaceae, Solieriaceae, Hypneaceae and Furcellariaceae); howe-
ver, this substance has not been investigated in Laurencia species. In this study, two native
species of Laurencia within the Persian Gulf were investigated to extract carrageenans.
Therefore, the major aims of this study included extraction, optimization and purification of
carrageenans from Laurencia snyderiae, a native red algae of Persian Gulf.
Material and Methods: Laurencia snyderiae and Laurencia papillosa were identified based
on their morphological characteristics. An experimental design was carried out using Design
Expert Software to produce and optimize extraction of semi-refined carrageenans. The
software programmed 18 treatments based on temperature, boiling time and KOH
concentration. Products of the treatments were prepared for rheometric analyses (viscosity
measurements). Optimization was carried out using the software based on the maximum
viscosity. Refined carrageenan efficiency was assessed using four extraction methods.
Moreover, Fourier-transform infrared spectroscopy and nuclear magnetic resonance
spectroscopy spectra were compared. Laurencia snyderiae was selected for further inves-
tigation.
Results and Conclusion: Based on the rheometric analyses, a semi-refined carrageenan
solution was identified as a non-Newtonian pseudo-plastic fluid. The optimum treatment was
investigated for Laurencia snyderiae at 65 °C for 35 min at KOH concentration of 7% w/v.
Results of these two analyses showed that the refined carrageenans from Laurencia snyderiae
included the lambda type. The highest efficiency was achieved using dialysis method (37%).
Based on the abundance of the Laurencia snyderiae on the Persian Gulf coasts in all seasons,
further studies on carrageenan with higher purities enable use of these substance in various
industries. Broader rheological studies can precisely assess cha