Synthesis and Characterization of Novel Stevioside Glucoside Using Dextransucrase from Leuconostoc mesenteroides

Abstract

Stevioside (Ste) is approximately 143-fold as sweet as sucrose at a concentration of 0.025%, which is why Ste has been used as a low-caloric natural sweetener. However, its bitter aftertaste minimizes its use for human consumption and limits its application in other food or pharmaceutical products. In this study, novel Stevioside Glucoside (novel Ste-Gs) using dextransucrase from Leuconostoc mesenteroides. Using the response surface methodology (RSM), the conversion yields were evaluated and reached to 85%. Each purified Ste-Gs was obtained by using high-performance liquid chromatography (HPLC) with amino column. The structures of Ste-Gs and novel Ste-Gs were elucidated by nuclear magnetic resonance (NMR) to be 13-O-β-sophorosyl-19-O-β-isomaltosyl-steviol and 13-O-[β-D-glucosyl (1 → 2)-β-nigerosyl]-19-O-β-isomaltosyl-steviol, respectively. Improved intensities of sweetness were observed for Ste-Gs and novel Ste-Gs, which are respectively 1.10 (158) and 1.41 (201) times sweeter than Ste. The quality of those two compounds was also improved compared to that of Ste. The biochemical properties of novel Ste-Gs were also characterized. The stability of Ste, Ste-Gs and novel Ste-Gs under pH 2, at 60 °C after 48 h were evaluated as 75.47±0.17%, 84.13±0.03%, and 85.94±1.10%, respectively. The solubilization ability of curcuminoids with Ste, Ste-Gs and novel Ste-Gs was from 8.07 ± 0.12 to 9.40 ± 0.12 mg per 10 g and that of idebenone with Ste, Ste-Gs and novel Ste-Gs was decreased from 9.94. ± 0.04 to 4.40 ± 0.38 mg per 10 mg.