Rubusoside is a precious bioactive sweetener which mainly exists in Chinese sweet tea plant (Rubus suavissimus S. Lee), while stevioside is an abundant natural sweetener with bitter aftertaste. In this work, a β-galactosidase from Aspergillus sp. presented specific hydrolytic activity on β-1,2 glucosidic linkage of stevioside, and converting stevioside to rubusoside. The hydrolytic activity was weak on the natural stevioside analogs, which makes the process a promising approach to produce rubusoside and utilize stevioside. The highest steviosides conversion was 98.3%, accompanying with a rubusoside yield of 91.4%.
Highlight:
► A rare natural sweetener rubusoside was synthesized from abundant stevioside.
► The β-galactosidase presented specific hydrolytic activity on stevioside.
► The highest rubusoside yield was 91.4% with a stevioside conversion of 98.3%.