Green Extraction of Carrageenans from Mastocarpus stellatus

What if the secret to stronger, greener biopolymers lies in a humble red seaweed and a splash of hot water? This study turns up the heat—literally—to unlock carrageenans with remarkable properties.

Forget harsh chemicals—this research uses just water under high pressure and heat to pull valuable carrageenans from the red seaweed Mastocarpus stellatus. By varying temperatures from 70°C to 190°C, scientists could fine-tune the extraction process and observe how heat changes the final product.

The extracted biopolymers were put through a gauntlet of tests: infrared spectroscopy, nuclear magnetic resonance, rheology, and cell viability assays. The team also analyzed the seaweed's basic composition and the phytochemical profile of the liquid extracts, giving a full picture of what's inside.

Results showed that temperature dramatically affects the rheological behavior—how the carrageenans flow and stretch. Yields ranged from 10.2% to 30.2%, with the best results at 130°C. At that same sweet spot, the carrageenans also showed the strongest viscous properties, making them potentially useful for thickeners or gels.

Even more intriguing, extracts from 130°C inhibited cancer cell growth: 65% for ovarian carcinoma cells (A2780) and 59% for lung carcinoma cells (A549), with IC50 values of 0.31 mg/mL and 0.41 mg/mL, respectively. While not a cure, this hints at bioactive potential worth exploring further.

Key Points

• Subcritical water extraction yields 10.2–30.2% carrageenans from red seaweed.
• 130°C gives highest yield and strongest rheological properties.
• Extracts inhibit ovarian (65%) and lung (59%) cancer cell growth.