Nguyen Thi Minh Tu^1*, Vu Hong Son¹, Nguyen Thi Thao¹, Nguyen Tien Huy¹, Hoang Thi Le Hang², Tran Thi Ngoc Thu³

¹Food Engineering Department, Hanoi University of Science and Technology, Hanoi, Vietnam

²Fruit and Vegetable Research Institute, Vietnam National University of Agriculture, Gia Lam, Hanoi, Vietnam

³University of Technology and Education, The University of Danang, Danang City, Vietnam

 

*Corresponding author’s email: tu.nguyenthiminhtu@hust.edu.vn

Received: 12 February 2026 / Revised: 21 May 2026 / Accepted: 03 June 2026 / Published Online: 19 June 2026

 

Abstract

 

Thermal processing is widely applied to improve the functional properties of ginseng through structural transformation of ginsenosides. This study evaluated the effects of controlled thermal treatment (75 °C in 70% ethanol) on the phyt^ochemical composition and bioactivity of Panax vietnamensis Ha et Grushv. cultivated in Son La, Vietnam. The major saponins investigated in this study included majonoside R2 (ocotillol-type); the protopanaxatriol (PPT)-type ginsenosides Rg1, Re, and Rh1, along with notoginsenoside R1; and the protopanaxadiol (PPD)-type ginsenosides Rb1 and Rd. High-performance liquid chromatography analysis revealed that thermal treatment resulted in a significant reduction in key polar ginsenosides, specifically a 56.6% decrease in notoginsenoside R1 (from 0.99% to 0.43%) and a 35.9% decrease in ginsenoside Rg1 (from 3.15% to 2.02%), accompanied by the relative enrichment of less-polar derivatives formed through deglycosylation. Rd acted as an intermediate in the conversion pathway, while the characteristic ocotillol-type saponin Majonoside R2 showed notable thermal stability with partial structural modification. These compositional changes were strongly linked to enhanced antioxidant activity, demonstrated by reduced DPPH IC₅₀ values after processing. The results demonstrate that integrated hydrothermal extraction, which replicates the traditional practices currently used by ginseng farmers, effectively modulates the polarity balance of the saponin matrix and enhances the biofunctional quality of P. vietnamensis. This approach provides a practical, scientifically validated framework for developing value-added ginseng products through a thermal process that significantly improves antioxidant potential.

 

Keywords: Antioxidant, Bio-activity, Ginsenoside transformation, Ocotillo-type saponins, Panax vietnamensis, Thermal processing

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