The Effect of Extraction Conditions on Chemical and Thermal Characteristics of Kappa-Carrageenan Extracted from Hypnea bryoides. (1st August 2019)

• Record Type: Journal Article
• Authors: Al-Nahdi, Zainab Mohammed; Al-Alawi, Ahmed; Al-Marhobi, Insaaf
• Other Names: Patzner Robert A. Academic Editor.
• Is Part Of: Journal of marine biology. Volume 2019(2019)
• Publication Date: 2019-08-01
• Subjects: Marine biology -- Periodicals; Marine biology; Periodicals; 578.77
• DOI: 10.1155/2019/5183261
• Languages: English
• ISSNs: 1687-9481

Abstract

Abstract : Hypnea bryoides collected from the Arabian Sea on the southern coast of Oman was investigated for κ -carrageenan optimal extraction conditions. The effects of different conditions of alkali treatment (4, 6, and 8% w/v NaOH), temperatures (70, 75, and 80°C), and time (2, 2.75, 3.5 hours) on carrageenan yield and chemical and thermal properties were evaluated. Yield was significantly affected by alkaline concentration and temperature, with highest value of 26.74 ± 5.01%. Molecular weights of the extracted carrageenan were significantly reduced by increased temperatures and ranged from 5.95 ± 0.49 × 10 5 Da to 13.90 ± 0.14 × 10 5 . FTIR showed that samples under all extraction conditions were similar and confirmed the presence of κ -carrageenan with no traces of μ -precursor. Sulfate content was also significantly reduced by alkaline concentration (from 4% to 6%) and ranged from 7.62 ± 5.52% to 17.02 ± 0.14. Thermal properties showed more sensitivity towards temperature and alkaline strength parameter than time. In addition, melting and gelling temperatures were significantly correlated with the molecular weight, but not sulfate content. In conclusion, mild extraction conditions were found to be more efficient in introducing the intended structural modification while getting the highest yield and quality.