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Rheological Properties and Decomposition Rates of Gellan Gum

Dhameri, Sulaiman Ali A.
http://orcid.org/0000-0002-8013-4003
http://rave.ohiolink.edu/etdc/view?acc_num=toledo1562780919692096

Abstract Details

2019, Master of Science, University of Toledo, Chemical Engineering.
Low acyl gellan gum (LA-GAGR) is a microbial polysaccharide that forms a viscoelastic gel when mixed with hyaluronic acid and β-tri- calcium phosphate (TCP). The effects of concentrations of the cross-linker (TCP) and LA-GAGR on the rheological properties and decomposition of the gels were studied. The degree of cross-linking of LA-GAGR was controlled with TCP content to determine its effects on the viscoelastic properties and release rate of LA-GAGR from the gel. The gels appeared thicker and opaquer with increasing TCP concentration. Three concentrations, 0.0 wt%, 0.5 wt%, and 1.0 wt% of TCP were examined with 0.15 wt% and 0.30 wt% of LA-GAGR. 5 wt% TCP is a maximum weight percentage that can be added to LA-GAGR, above which the TCP begins to precipitate out. Flow sweep tests showed that all tested gels are shear thinning and that the gel made with 1.0 wt% TCP and 0.30 wt% LA-GAGR displayed the highest viscosity with the experimental value of 675 Pa·s at 0.1 s-1. However, gels made with 0.0 wt% TCP and 0.15 wt% LA-GAGR showed the lowest viscosity, 5.8 Pa·s at 0.1 s-1. The gel made with 0.0 wt% TCP and 0.15 wt% LA-GAGR exhibited the lowest loss and storage moduli of 0.5 Pa and 0.056 Pa, respectively. The gel made with 1.0 wt% TCP and 0.30 wt% LA-GAGR exhibited the highest loss and storage moduli of 116 Pa and 437.8 Pa, respectively. The gels made with 0.30 wt% LA-GAGR and TCP concentrations of 0.5 wt% and 1.0 wt% showed typical viscoelastic behaviors. For the release rates of LA-GAGR the gels, the gel made with 1.0 wt% TCP and 0.30 wt% LA-GAGR exhibited the lowest average release rate of 0.10 mg h-1, releasing all of LA-GAGR within 13 days. The low degree of crosslinking, due to the decrease of TCP, decreased the decomposition time of the gel to 8 days for the gel containing 0.30% LA-GAGR, 0.5% TCP. The properties of the gels varied depending on the method of mixing. When components were added gradually during mixing, the gel resulted in thicker and opaquer gels with slower decomposition time of 240 h compared to the gel formed via one time-addition of components decomposed in 216 h. It is concluded that, with a given LA-GAGR concentration, high TCP concentrations increase the degree of cross-linking of the polysaccharide, and therefore, the gel behaves more elastic and less fluidic and decomposes slower.
Dong-Shik Kim (Committee Chair)
Joshua Park (Committee Member)
Maria Coleman (Committee Member)
44 p.
Biochemistry; Biomedical Engineering; Biomedical Research; Chemical Engineering; Chemistry
Release rate, Polysaccharides gel, Storage modulus, Loss modulus, Gellan gum, Tricalcium phosphate TCP ,LA-GAGR

Recommended Citations

Citations

  • Dhameri, S. A. A. (2019). Rheological Properties and Decomposition Rates of Gellan Gum [Master's thesis, University of Toledo]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1562780919692096

    APA Style (7th edition)

  • Dhameri, Sulaiman. Rheological Properties and Decomposition Rates of Gellan Gum. 2019. University of Toledo, Master's thesis. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=toledo1562780919692096.

    MLA Style (8th edition)

  • Dhameri, Sulaiman. "Rheological Properties and Decomposition Rates of Gellan Gum." Master's thesis, University of Toledo, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1562780919692096

    Chicago Manual of Style (17th edition)

toledo1562780919692096
626
© 2019, some rights reserved.Creative Commons License Rheological Properties and Decomposition Rates of Gellan Gum by Sulaiman Ali A. Dhameri is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 Unported License. Based on a work at etd.ohiolink.edu.
This open access ETD is published by University of Toledo and OhioLINK.