A novel black ginseng processing method for optimizing rare ginsenosides with bioactivity and sustainability

Traditional black ginseng (BG) production requires resource-intensive multiple steaming-drying cycles. This study aimed to develop an efficient, sustainable method for producing novel black ginseng (hereafter referred to as Dark Ginseng, DG) with optimized rare ginsenoside contents with biological efficacy.

A sous vide-inspired enclosed system heating method was used, where sealed packaging retained water vapor to enable continuous moisture-mediated ginsenoside hydrolysis, fundamentally different from conventional open-system steam processing. Response surface methodology was employed to optimize the production parameters. DG underwent comprehensive morphological, colorimetric, and phytochemical characterizations. Biological activities were assessed by quantifying collagen gene expression in fibroblasts and inflammatory marker levels in keratinocytes.

Optimal parameters (3-fold water ratio, 100 °C, 120 h duration) demonstrated excellent agreement with the regression model. DG exhibited physical features comparable to conventional BG, while achieving reduced processing time (42 %), lower carbon dioxide emissions (64 %), and cost reduction (81 %), and contained rare ginsenosides (ginsenosides Rg₃, Rg₅, and Rk₁) with no detectable hazardous substances. The DG extract significantly upregulated collagen synthesis genes COL4A1 (1.55-fold) and COL7A1 (2.29-fold) expressions in fibroblasts and exhibited anti-inflammatory effects through dose-dependent reduction by 50 %-80 % of cytokine IL6, IL8, and COX2 expression levels in stimulated keratinocytes.

This innovative process developed in this study replaces the nine sequential steaming-drying cycles required for conventional BG production, with a single sequence involving sous vide-like heating, offering sustainability and economic advantages, while suggesting potential for applications in cosmetics and functional foods.