Hydrophilic
β-sitosterol sugar esters were synthesized by
a two-step biocatalytic approach using β-sitosterol vinyl adipate
as an intermediate. The maximum conversion (above 90%) of β-sitosterol
vinyl adipate was achieved using the saccharides glucose, sucrose,
and raffinose. The chemical structure of the synthesized esters was
confirmed by various techniques. The investigation of physical properties
revealed that β-sitosterol sugar esters had enhanced water solubility
(3.0–8.0 mM at 35 °C), reduced crystallinity, and high
wettability. Their lyotropic liquid crystal properties were observed
by polarized light microscopy. Furthermore, β-sitosterol sugar
esters could be hydrolyzed into β-sitosterol adipate under simulated
intestinal conditions at a low rate (2.83–18.14%). Most β-sitosterol
sugar esters probably entered into intestinal bile salt micelles with
ester bonds intact and showed up to 10-fold higher in vitro bioaccessibility
than free β-sitosterol in non-fat systems. The excellent physical
and functional characteristics of β-sitosterol sugar esters
suggested their great potential application in the food industry.