An ultra melt-resistant hydrogel from food grade carbohydrates

Thompson, Benjamin R.; Horozov, Tommy S.; Stoyanov, Simeon D.; Paunov, Vesselin N.

Abstract

© 2017 The Royal Society of Chemistry. We report a binary hydrogel system made from two food grade biopolymers, agar and methylcellulose (agar-MC), which does not require addition of salt for gelation to occur and has very unusual rheological and thermal properties. It is found that the storage modulus of the agar-MC hydrogel far exceeds those of hydrogels from the individual components. In addition, the agar-MC hydrogel has enhanced mechanical properties over the temperature range 25-85 °C and a maximum storage modulus at 55 °C when the concentration of methylcellulose was 0.75% w/v or higher. This is explained by a sol-gel phase transition of the methylcellulose upon heating as supported by differential scanning calorimetry (DSC) measurements. Above the melting point of agar, the storage modulus of agar-MC hydrogel decreases but is still an elastic hydrogel with mechanical properties dominated by the MC gelation. By varying the mixing ratio of the two polymers, agar and MC, it was possible to engineer a food grade hydrogel of controlled mechanical properties and thermal response. SEM imaging of flash-frozen and freeze-dried samples revealed that the agar-MC hydrogel contains two different types of heterogeneous regions of distinct microstructures. The latter was also tested for its stability towards heat treatment which showed that upon heating to temperatures above 120 °C its structure was retained without melting. The produced highly thermally stable hydrogel shows melt resistance which may find application in high temperature food processing and materials templating.

Citation

Thompson, B. R., Horozov, T. S., Stoyanov, S. D., & Paunov, V. N. (2017). An ultra melt-resistant hydrogel from food grade carbohydrates. RSC advances, 7(72), 45535-45544. https://doi.org/10.1039/c7ra08590g

• Journal Article Type: Article
• Acceptance Date: Sep 16, 2017
• Online Publication Date: Sep 25, 2017
• Publication Date: Sep 25, 2017
• Deposit Date: Oct 12, 2017
• Publicly Available Date: Oct 12, 2017
• Journal: RSC advances
• Print ISSN: 2046-2069
• Electronic ISSN: 2046-2069
• Publisher: Royal Society of Chemistry
• Peer Reviewed: Peer Reviewed
• Volume: 7
• Issue: 72
• Pages: 45535-45544
• DOI: https://doi.org/10.1039/c7ra08590g
• Keywords: General Chemistry; General Chemical Engineering
• Public URL: https://hull-repository.worktribe.com/output/455606
• Publisher URL: http://pubs.rsc.org/en/content/articlelanding/2017/ra/c7ra08590g#!divAbstract
• Additional Information: : This document is CrossCheck deposited; : Benjamin R. Thompson (ORCID); : Tommy S. Horozov (ORCID); : Simeon D. Stoyanov (ORCID); : Simeon D. Stoyanov (ResearcherID); : Vesselin N. Paunov (ORCID); : The Royal Society of Chemistry has an exclusive publication licence for this journal; OPEN ACCESS: This article is freely available. This article is licensed under a Creative Commons Attribution 3.0 Unported Licence (CC BY 3.0); : Received 3 August 2017; Accepted 16 September 2017; Version of Record published 25 September 2017
• Contract Date: Oct 12, 2017