Microwave-assisted extraction of the Carrageenan from Hypnea musciformis (Cystocloniaceae, Rhodophyta)

Hypnea musciformis (Wulfen in Jacqu.) J. V. Lamour. (Rhodophyta) was investigated for its carrageenan production. Traditionally, the desulfation process for carrageenans has been promoted by an alkaline treatment of up to 3 h by conventional heating during carrageenan extraction. New extraction techniques based on microwave irradiation may accelerate this reaction with the advantages of reduced consumption of solvents, energy, and extraction time, suggesting the feasibility of this method as a “Green” technology. In this study, aqueous- and alkali-treated carrageenans from H. musciformis collected along Quintana Roo coast of Yucatan Peninsula (Mexico) were extracted by conventional method and by microwave-assisted extraction (MAE). Microwave irradiation in closed vessels was used to carry out the alkaline modification. The influence of temperature (85, 95, and 105 °C) and extraction time (10 and 20 min) in MAE was investigated in terms of yield, sulfate, and 3,6-anhydrogalactose contents, and Fourier transformed infrared spectra. Although lower carrageenan yields were obtained during MAE extraction, the κappa/iota hybrid carrageenan obtained by this novel method is comparable to that extracted by conventional technique. At the maximum temperature used for MAE (105 °C), an increase of 3,6-anhydrogalactose as well as an increase of the κappa-proportion was observed indicating that MAE could be an adequate procedure for carrageenan extraction of H. musciformis; however, further extraction parameters should be tested to optimize extraction.