Sucralose hydrogels: Peering into the reactivity of sucralose versus sucrose under lipase catalyzed trans-esterification. (November 2022)

• Record Type: Journal Article
• Authors: Samateh, Malick; Marwaha, Siddharth; James, Jose K.; Nanda, Vikas; John, George
• Is Part Of: Carbohydrate research. Volume 521(2022)
• Publication Date: 2022-11
• Subjects: Sucrose -- Sucralose -- Enzyme catalysis -- Molecular gels -- Self-assembly -- Molecular modeling; Carbohydrates -- Periodicals; Chemistry, Organic -- Periodicals; Biochemistry -- Periodicals; Carbohydrates -- Periodicals; Chimie organique -- Périodiques; Glucides -- Périodiques; Biochemistry; Carbohydrates; Chemistry, Organic; Periodicals; Electronic journals; 507.78
• DOI: 10.1016/j.carres.2022.108647
• Languages: English
• ISSNs: 0008-6215

Abstract

Abstract: Sucralose differs from sucrose only by virtue of having three Cl groups instead of OH groups. Its intriguing features include being noncaloric, noncariogenic, ∼600 times sweeter than sucrose, stable at high temperatures/acidic pH's, and void of disagreeable aftertastes. These properties are attractive as food additive, one of which is as hydrogel obtainable via the technique of molecular gelation using a sucralose-derived low-molecular weight gelator (LMWG). Such hydrogels are highly responsive to external stimuli like temperature, because the LMWGs self-assemble via non-covalent interactions and could thus be utilized in applications like control-release. We found that sucralose to be unreactive under lipase biocatalysis, unlike sucrose. Hence, the aim of this work was (i) to use computational simulations to further understand sucralose's lack of enzymatic reactivity and (ii) to synthesize the sucralose-based amphiphiles using conventional chemical synthesis and systematically study their tendency towards hydrogelation. Sucrose and sucralose were docked with a high-resolution atomic structure of lipase B from Candida antarctica, modeling the esterification transition state with an active site serine. In extended molecular dynamics simulations, sucrose remained in the active site due to multiple sugar-protein hydrogen bonds. The oxygen-to-chlorine substitutions in sucralose disrupted this hydrogen bonding network. Consistent with observed lack of enzymatic conversion, in multiple simulations, sucralose would rapidly dissociate from the active site. The sucralose-based LMWGs were subsequently synthesized using base-catalyzed conventional chemical synthesis. Three of the sucralose-based amphiphiles (SL-5, SL-6 and SL-7) proved to be successful hydrogelators. The gelators also showed the ability to gel selected beverages. The LMWGs gelled quantities of water and beverage up to 71 and 55 times their weight, respectively, and remain thermally stable up to 144 °C. Graphical abstract: Modeling of the enzyme-substrate complex- Using the experimental structure of Candida lipase B, the alkyl ester and sugar were introduced into the active site pocket highlighted in red. Image 1 Highlights: A first of its kind studies on the reactivity of sucralose versus sucrose in enzyme enabled transesterification reaction. Molecular dynamics studies confirmed the inactivity of sucralose towards enzymatic transesterification reaction. Sucralose-based amphiphiles (SL-5, SL-6 and SL-7) proved to be successful hydrogelators. Sucralose-based amphiphiles may find application in non-calorific sweet foods for people suffering from Dysphagia.