Structure and rheological properties of carrageenans extracted from different red algae species cultivated in Cam Ranh Bay, Vietnam

κ-Carrageenan was extracted from three subspecies of Kappaphycus alvarezii—K. alvarezii, K. striatum, and K. malesianus—and ι-carrageenan was extracted from Eucheuma denticulatum. Mild water extraction was used in order to obtain carrageenan in the native form. The yield was higher for the raw extract from K. alvarezii (42%) than for the other species (32–37%). NMR showed that the samples contained only small amounts of other carrageenan types....