Characterization and rheological study of the galactomannan extracted from seeds of Cassia grandis

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• 作者：Priscilla B.S. Albuquerque^a ; Wilson Barros Jr.^b ; Gustavo R.C. Santos^c ; Maria T.S. Correia^a ; Paulo A.S. Mourã ; o^c ; José ; A. Teixeira^d ; Maria G. Carneiro-da-Cunha^a ; ^{mgcc@ufpe.br" class="auth_mail}
• 关键词：Galactomannan ; Cassia grandis ; Rheology ; X-ray ; NMR ; Characterization.
• 刊名：Carbohydrate Polymers
• 出版年：15 April, 2014
• 年：2014
• 卷：104
• 期：Complete
• 页码：127-134
• 全文大小：1417 K

文摘

Galactomannan extracted from seeds of Cassia grandis with 0.1 M NaCl, followed by ethanol precipitation, presented a yield of 36 卤 8%. The polysaccharide has a constant mannose/galactose ratio (2.44:1). Methylation analysis, one and two dimensional NMR spectroscopy confirmed that the polysaccharide has a central core composed of 4-linked 尾-mannose units, with branches of galactose, linked to the carbohydrate core through 伪(1-6) linkage. The amorphous nature of the galactomannan was confirmed by X-ray diffraction. Rheological characterization exhibited Newtonian plateaus followed by shear-thinning zones characteristic of polymer solutions up to 1.5% (w/v) and above this value the system exhibited yield stress associated with a weak gel. Adjusting stress-strain curves confirmed a 1.6% (w/v) as the galactomannan concentration value for the sol-gel transition. These results indicate that the galactomannan extracted from C. grandis seeds presents rheological characteristics suitable for applications in pharmaceutical, biomedical, cosmetic and food industries.