Pulsed electric field treatment combined with commercial enzymes converts major ginsenoside Rb1 to minor ginsenoside Rd

• A novel technique for producing minor ginsenoside Rd is proposed.
• The strong ability of the PEF treatment combined with β-glucosidase converted ginsenoside Rb1 to Rd in a short period.
• The mechanism relies on accelerating the speed of the enzymatic reaction system under pulsed electric field treatment.
• Response surface methodology (RSM) was carried out to optimize the yield of ginsenoside Rd under CPEF treatment.

Ginsenoside Rd is an important secondary metabolite in ginseng, and has various pharmacological activities. In this study, pulsed electric field (PEF) treatment combined with commercial enzyme (CPEF) was used to convert major ginsenoside Rb1 to the more active minor ginsenoside Rd. The commercial β-glucosidase was the most efficient at producing ginsenoside Rd under PEF treatment. Response surface methodology (RSM) was carried out to optimize the yield of ginsenoside Rd under CPEF treatment. The experimental data were fitted to a second-order polynomial equation. Optimal treatment conditions were as follows: electric field intensity 15 kV cm− 1, pulse number 8 and enzyme concentration 3% (w/w). Under these conditions, the yield of ginsenoside Rd achieved 91.42%, matching well with the predicted value. The structure of the product was identified as ginsenoside Rd by 1H NMR and 13C NMR. These results suggested that CPEF treatment would be an effective method to convert ginsenoside Rb1 to ginsenoside Rd.Industrial relevanceThis study will give a novel technique for producing minor ginsenoside Rd. The use of pulsed electric field combined with commercial β-glucosidase produced higher yield of ginsenoside Rd in short time, compared with conventional treatments. Available data provided in this study will benefit the industrial production of minor ginsenoside Rd.