A comparative study on physicochemical and micellar solubilization performance between monoglucosyl rebaudioside A...

Rebaudioside A (RA) and its monoglucosyl derivative, as like rebaudioside D (RD) are the most popular stevia glycosides but possess poor solubility in water, which limited their application as edible surfactants, the applications as in micellar solubilization and drug delivery. Meanwhile, effect of the monoglucosyl attached to RA moiety remains unclear.

Monoglucosyl rebaudioside A (RAG1) was synthesized via hydrolyzing the transglycosylation product of RA with 95% of RA converted. RAG1 content in raw reaction mixture was as high as 69.5% of total glycosides, and harvested with a content of 88.2% by simple filtration. The RAG1 exhibited an aqueous solubility of 87 folds of RA or 391 folds of RD at 25 °C. The surface activity of RAG1 solution was higher than RA and invincible to RD. The RAG1 micelles promoted aqueous solubility of idebenone (IDE) up to 500 folds higher at 25 °C. The cumulative release rate of IDE encapsulated in RAG1 micelles was 777.5% or 456.7% higher of that of free IDE in simulated gastric/intestinal fluids in 14 h, respectively. The RAG1-IDE remained the same in 98 days at 25 °C.

The α-linked glucosyl to RA induced higher hydrophilicity and surface activity than that resulted by β-linked glucosyl, making RAG1 not only dramatically raise the aqueous solubility of RA, but also endow IDE folds higher in bioaccessibility, yet making the capsule stable at storage. The results would provide a new edible delivery nanocarrier for encapsulation of hydrophobic bioactive components. © 2021 Society of Chemical Industry.