Transglucosylation of caffeic acid by a recombinant sucrose phosphorylase in aqueous buffer and aqueous-supercritical CO₂ media

Polyphenolic compounds, such as caffeic acid, offer many health benefits, but their industrial applications are limited because of their low solubility in water and instability under UV light or heat. In this study, we enzymatically produced caffeic acid glucosides, in both aqueous buffer and aqueous-supercritical carbon dioxide (SC-CO₂) media, using a recombinant sucrose phosphorylase (SPase) from Bifidobacterium longum. By using LC/MS/MS analysis, we verified that the enzymatic reaction products were caffeic acid monoglucosides and diglucosides. Under SC-CO₂, the amounts of the reaction products from the enzyme reaction were smaller than those in the aqueous reaction medium. However, this is the first report of the transglucosylation of caffeic acid by SPase, and also the first enzymatic reaction with phenolic compounds conducted in a SC-CO₂ phase.