Thermal and Rheological Properties of a Family of Botryosphaerans Produced by Botryosphaeria rhodina MAMB-05

Molecules

Paulo R.M.S. Fonseca¹  Robert F.H. Dekker¹  Aneli M. Barbosa¹  Joana L.M. Silveira¹  Ana F.D. Vasconcelos¹  Nilson K. Monteiro¹  Gabriel Aranda-Selverio¹ 

[1] ¹Department of Physics, Chemistry and Biology, Faculty of Science and Technology, University Estadual Paulista, Presidente Prudente 19060900, Brazil

关键词: b-glucans;    botryosphaeran;    thermal analysis;    FT-IR spectroscopy;    rheology;   

DOI  :  10.3390/molecules16097488

来源: mdpi

【 摘 要 】

Differential scanning calorimetry (DSC), thermogravimetry (TG) and Fourier-transform infra-red spectroscopy (FT-IR) analyses were performed to investigate changes in the physico-chemical properties of botryosphaerans, a family of exopolysaccharides (EPS) produced by the fungus Botryosphaeria rhodina MAMB-05 grown on glucose (EPS_GLC), sucrose (EPS_SUC) and fructose (EPS_FRU). A slight endothermic transition and small mass loss attributable to the removal of water of hydration were observed in the DSC and TG analyses, respectively, for the three EPS samples. The FT-IR spectra confirmed no structural changes occurred during thermal treatment. Viscometry was utilized to obtain information on the rheological behaviour of the EPS in aqueous solutions. The Power Law and Cross Equations determined the natural pseudoplastic characteristics of the EPS. Comparatively, results obtained for EPS produced when B. rhodina MAMB-05 was grown on each of the three carbohydrate sources demonstrated similar apparent viscosity values for EPS_GLC and EPS_SUC, while EPS_FRU displayed the lowest apparent viscosity of the three botryosphaerans, suggesting a higher degree of ramification and lower Mw. EPS_GLC and EPS_SUC possessed similar degrees of ramification. The slight differences found in their viscosities can be explained by the differences in the type of branching among the three botryosphaerans, thus varying the strength of intermolecular interactions and consequently, consistency and viscosity. The physico-chemical studies of botryosphaerans represent the originality of this work, and the knowledge of these properties is an important criterion for potential applications.

【 授权许可】

CC BY   
This is an open access article distributed under the Creative Commons Attribution License (CC BY) which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.