Next Article in Journal
Probiotic Potential of Lactic Acid Bacteria Strains Isolated from Artisanal Cheeses: Impact on Listeria monocytogenes Infection
Previous Article in Journal
Applied Bioelectrochemistry: Plastic Degradation and Energy Generation Using Klebsiella oxytoca in Microbial Fuel Cells
 
 
Search for Articles:
Title / Keyword
Author / Affiliation / Email
Journal
Article Type
 
 
Advanced Search
 
Section
Special Issue
Volume
Issue
Number
Page
 
Journals
Fermentation
Volume 11
Issue 6
10.3390/fermentation11060342
fermentation-logo
Submit to this Journal Review for this Journal Propose a Special Issue
► Article Menu

Article Menu

share Share announcement Help format_quote Cite question_answer Discuss in SciProfiles
first_page
settings
Order Article Reprints
Font Type:
Arial Georgia Verdana
Font Size:
Aa Aa Aa
Line Spacing:
Column Width:
Background:
Article

Lactic Acid Bacteria as Probiotics Improve Bioactive Compounds in Radix Angelica gigas (Danggui) via Solid-State Fermentation

by
Jeong Heo
1,†,
Youn-Kyung Ham
1,†,
Ah Yeong Choi
2,
Hyouk Yoon
2 and
Ha Gyun Sung
1,*
1
Department of Animal Science, Sangji University, Wonju-si 26336, Gangwon-do, Republic of Korea
2
Pet21 Co., Ltd., Dongdaemun-du, Seoul 02569, Republic of Korea
*
Author to whom correspondence should be addressed.
†
These authors contributed equally to this work.
Fermentation 2025, 11(6), 342; https://doi.org/10.3390/fermentation11060342
Submission received: 16 April 2025 / Revised: 1 June 2025 / Accepted: 7 June 2025 / Published: 12 June 2025
(This article belongs to the Special Issue Bioactive Compounds and Functional Properties of Fermented Foods)
Browse Figures
Review Reports Versions Notes

Abstract

Solid-state fermentation (SSF) is increasingly applied to enhance the functional properties of traditional herbal medicines. In this study, we investigated the effect of lactic acid bacteria (LAB) and other probiotic strains on the bioactive profile of Radix Angelica gigas (Danggui) during SSF. SSF was carried out by incubating a mixture of the herbal powder and distilled water (1:1, pH 7.0) with LAB strains (Lactobacillus rhamnosus, L. acidophilus, L. buchneri, L. reuteri, L. plantarum) and additional microbes (Bacillus subtilis, Saccharomyces cerevisiae) under controlled conditions. The 2,2-Diphenyl-1-picrylhydrazyl (DPPH) and 2,2′-Azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical scavenging activities and total phenolic and flavonoid contents were measured. L. buchneri exhibited the highest growth, with significant proliferation observed on days 4 and 6, especially at 30 °C (p < 0.05). The DPPH and ABTS radical scavenging activities and total phenol and total flavonoid contents were increased by up to 230% (35 °C), 111% (30 °C), 137% (30 °C and 35 °C), and 133% (35 °C), respectively, in fermented herbs compared with those in non-fermented herbs. Antioxidant levels (DPPH, phenol, and flavonoid) exhibited a significant positive correlation with bacterial growth and a significant negative correlation with pH in SSF, but ABTS did not exhibit any statistically significant correlation with bacterial growth or pH. Moreover, multi-strain fermentations involving L. acidophilus and L. plantarum significantly increased the antioxidant activities compared to single-strain fermentations (p < 0.05). These findings suggest that SSF using probiotic LAB can significantly improve the bioactive composition of Radix Angelica gigas, providing a scientific method for modernizing traditional herbal medicine with potential uses in human and animal health.

1. Introduction

Natural materials comprise numerous components with diverse physiological and biochemical properties. Radix Angelica gigas, also known as the Korean Angelica root or Danggui, is the dried root of Angelica gigas Nakai (Umbelliferae) [1]. A. gigas has been used as a traditional herbal medicine in East Asian countries for a long time, particularly in Korea, China, and Japan, to treat gynecological diseases and anemia. It also exhibits anti-inflammatory, analgesic, anti-cancer, and hair growth-promoting properties [2,3]. Despite these beneficial properties, the clinical efficacy of many traditional herbal medicines is limited by low bioavailability and the presence of potentially toxic or inactive compounds [3,4,5]. Therefore, the exploration of strategies to improve the bioactivity and safety profile of herbal products has gained increased research interest.
Microbial fermentation is a traditional processing technique that has long been used in oriental herbal medicine. Various microorganisms, such as LAB, Bacillus sp., Saccharomyces sp., and medicinal fungi, are commonly used for the fermentation of traditional herbs [6]. Compared to spontaneous fermentation by environmental microbiota, fermentation using well-characterized probiotic strains can more effectively enhance therapeutic effects and reduce potential toxicity [3,6,7]. For instance, Lactobacillus-fermented herbs have shown improved in vitro anti-inflammatory activity, lowered endotoxin and C-reactive protein (CRP) levels, and reduced intestinal permeability [8]. These beneficial effects are attributable to both the metabolic activities of probiotics and their interactions with the herbal matrix [3,9], supporting the growing interest in probiotic-mediated fermentation as a strategy for functional enhancement.
Fermentation techniques are typically categorized as liquid fermentation and solid-state fermentation (SSF), depending on the physical state of the substrate. SSF uses one or several probiotic strains to ferment herbal biomass under low-moisture conditions [3]. It has gained interest due to its advantages, including low wastewater generation, low cost, simple procedure, high conversion rate, and high yield compared with liquid fermentation [10,11,12]. However, its standardization remains challenging, particularly regarding the control of variables such as pH, temperature, and incubation time [13]. Given the growing interest in probiotics for human and animal health, efforts to standardize efficient SSF techniques using customized probiotic strains and fermentation conditions are promising strategies for enhancing the functional properties of herbal materials.
This study aimed to investigate the potential of SSF in enhancing the health benefits of Radix Angelica gigas. We evaluated the changes in the antioxidant properties of Radix Angelica gigas during SSF using various bacterial strains, including lactic acid bacteria (LAB) as probiotics. Our findings may contribute to the standardization of SSF technology and encourage the efficient application of oriental herbal medicines in modern healthcare.

2. Materials and Methods

2.1. Materials

The oriental herbs used in this study were the dried roots of Angelica gigas (Danggui) (Sechang Co., Ltd., Seoul City, Republic of Korea). The roots were harvested from Danggui cultivated for one year in Jecheon-si, Chungcheong-do, South Korea. The herbs were prepared as a fine powder using a crusher and mill (Nankook Crusher Co., Ltd., Gyeonggi-do, Republic of Korea) for SSF and stored at 4 °C before use.

2.2. Probiotics Screening for SSF

To screen probiotics for SSF, LAB, including Lactobacillus rhamnosus, L. acidophilus, L. buchneri, L. reuteri, and L. plantarum, as well as other probiotic strains, including Bacillus subtilis and Saccharomyces cerevisiae (Agrokorea Co., Ltd., Seoul City, Republic of Korea), were evaluated. Each strain was inoculated at a concentration of 1 × 104 colony-forming unit (CFU)/g into solid substrates prepared by mixing the Radix Angelica gigas powder and distilled water at 1:1 (w/v). The mixture was incubated at 37 °C for 36 h. All the cultures were performed in triplicate, and bacterial counts (CFU/g) were estimated. Initially, strains exhibiting the highest growth rates were selected to analyze the relationship between cell growth and antioxidant properties under varying incubation temperatures and durations. In subsequent experiments, the selected LAB showing good proliferation were selected to evaluate their fermentative efficiency and antioxidant properties in SSF, using single- or multiple-strain inoculation strategies.

2.3. Characteristics of Cell Proliferation in SSF Using LAB

To evaluate according to the incubation temperature, a strain showing the best growth was chosen. It was inoculated at 1 × 105 CFU/g of solid substrates and incubated at 25 °C, 30 °C, and 35 °C for 8 days. All the experiments were conducted in triplicate. Samples were collected every two days during the culture period to assess the bacterial growth and production of bioactive substances.
To monitor the effectiveness of the microbial inoculation types, two strains of LAB showing good proliferation were selected and inoculated to the solid substrate at 1 × 105 CFU/g, either as single-strain cultures or as mixed-strain cultures (1:1, w/w). The fermentation was carried out at 30 °C or 35 °C for 6 days, with all procedures carried out in triplicate. Samples were collected every two days during the culture period for analysis.
The LAB growth was measured as the viable bacterial cell count. The fermented samples were serially diluted to 10−8 in 0.85% sodium chloride solution, plated on MRS agar plates (BD, Franklin Lakes, NJ, USA), and incubated at 37 °C for 2 days. Afterward, the bacterial cell count (CFU/g) was determined. To measure the pH, the fermented samples were mixed with distilled water at a 1:9 (w/v) ratio and incubated at 4 °C for 10 min with spontaneous shaking at 100 rpm in a shaking incubator (BF-60SIR, BioFree Co., Ltd., Seoul, Republic of Korea). The supernatants were obtained by filtration using F1004 Grade filter paper (CHM Lab Croup, Terrassa-Barcelona, Spain), and the pH was measured using a pH meter (Starter 3100, Ohaus Co., Parsippany, NJ, USA).

2.4. Quantification of Bioactive Compounds

Herbal extracts were prepared according to the method described by Lee et al. [14], with minor modifications. Briefly, 3 g of dried samples was mixed with 10 volumes of hot water in a flask and continuously stirred for 3 h. The extraction procedure was repeated twice, and the mixture was centrifuged at 3000 rpm for 20 min. The supernatant was filtered, freeze-dried, and dissolved in dimethyl sulfoxide (DMSO), and the filtrate was used for subsequent assays.
The 2,2-Diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity was measured following the method described in a previous study, with some modifications [15]. Briefly, 20 μL oriental herb extracts was mixed with 180 μL DPPH methanolic solution in a 96-well plate and incubated in the dark for 30 min. The absorbance was measured at 517 nm using a microplate reader. The radical scavenging activity was calculated using the equation described by Carneiro et al. [15].
The 2,2′-Azino-bis(3-ethylbenzothiazoline-6-sulfonic acid)(ABTS) radical scavenging activity was evaluated using the method described by Re et al. [16]. ABTS solution (7 mM) was mixed with 2.45 mM potassium persulfate solution in a 1:1 ratio (v/v) and left in the dark for 12–16 h before the test to form an ABTS radical cation solution, which was then diluted with distilled water to an absorbance of 0.700 ± 0.05 at 734 nm. Then, 900 μL of the diluted ABTS solution was mixed with 100 μL herbal extract. The absorbance was measured at 734 nm after 1 min (for up to 6 min). The ABTS radical scavenging activity was calculated as described by Prior et al. [17].
The total phenolic content was measured according to the method described by Folin and Ciocalteu [18], with some modifications. Briefly, 0.2 mL extract was mixed with 1.8 mL distilled water in a test tube, and 0.2 mL Folin–Ciocalteu reagent was added. The mixture was allowed to react for 3 min, followed by the addition of 0.4 mL saturated sodium carbonate solution and mixing. Then 1.4 mL distilled water was added, and the mixture was left to stand at room temperature for 1 h. Absorbance was measured at 725 nm using a microplate reader. The results were expressed as gallic acid equivalents (GAE) using a calibration curve over 0.25–1.00 mM.
The total flavonoid content of the extract was determined according to the method described in previous studies [19,20], with some modifications. Briefly, 300 μL extract was mixed with 3.4 mL of 30% methanol, 150 μL of 0.5 M NaNO2 solution, and 150 μL of 0.3 M AlCl3·6H2O solution. After 5 min, 1 mL 1 M NaOH solution was added and mixed thoroughly. The absorbance was measured at 510 nm against a blank reagent. The total flavonoid content was calculated using the standard curve, which was prepared with quercetin solutions at 20, 40, 60, 80, and 100 mg/L.

2.5. Statistical and Correlation Analysis

All the experimental results are presented as the mean ± standard deviation from triplicate analyses (n = 3). Data were analyzed using SPSS statistical software (version 18; SPSS Inc., Chicago, IL, USA). A one-way analysis of variance (ANOVA) followed by Duncan’s multiple range test was conducted to determine significant differences at p < 0.05.
All statistical analyses and data handling were performed using R (version 4.2.1) in a UNIX-compatible environment [21]. Pearson’s correlation coefficients were calculated for all variable pairs using the R package with cor() function. To assess statistical significance, two-tailed p-values were obtained via the R package with cor.test() for each pair of variables, applying default settings to test the null hypothesis of zero correlation [21].

3. Results

3.1. Evaluation of Probiotic Growth in SSF Conditions

The cell growth and pH values of L. rhamnosus, L. acidophilus, L. buchneri, L. reuteri, L. plantarum, B. subtillis, and S cerevisiae were compared (Table 1). The analysis revealed that all the tested strains grew during SSF, with a corresponding reduction in pH after fermentation compared with that in non-fermented controls. L. acidophilus, L. buchneri, L. plantarum, and L. reuteri showed better growth than L. rhamnosus, B. subtillis, and S cerevisiae (p < 0.05). These four strains also showed a greater decrease in pH values post-fermentation, which correlated with their enhanced cell growth (p < 0.05). A Pearson’s correlation analysis between the bacterial growth and pH change for seven species (L. rhamnosus, L. acidophilus, L. buchneri, L. plantarum, L. reuteri, Bacillus subtilis, and S. cerevisiae) yielded a correlation coefficient of 0.925 (p = 0.003). In particular, L. buchneri exhibited the highest cell proliferation (706.76 ± 51.32 × 105 CFU/g), followed by L. acidophilus (627.00 ± 24.64 × 105 CFU/g) and L. plantarum (630.00 ± 20.00 × 105 CFU/g), compared with other strains (p < 0.05).

3.2. Effects of Culture Period and Temperature on Cell Growth and Antioxidant Activities of SSF Using L. buchneri

Based on the screening results, L. buchneri was selected due to its superior growth during the SSF of Radix Angelica gigas to evaluate the effects of incubation temperature and duration on bacterial proliferation and pH dynamics. The effects of culture temperature and duration on the growth of L. buchneri in the SSF of Radix Angelica gigas are shown in Figure 1A. L. buchneri showed different growth characteristics depending on the SSF temperature and period. The highest bacterial proliferation was observed on day 4 at 30 °C, significantly higher than at the other temperatures (p < 0.05). At 35 °C and 30 °C, growth peaked on day 4, whereas at 25 °C, the peak was delayed until day 6. Among all the conditions, 30 °C sustained higher bacterial viability throughout the incubation period. The pH changes during the SSF using L. buchneri are shown in Figure 1B. The pH gradually decreased as the bacteria grew at all temperatures. The pH levels decreased progressively as the fermentation progressed from days 0 to 2 of incubation and showed significantly lower values at 35 °C and 25 °C than that at 30 °C (p < 0.05) on day 2 of incubation. However, the pH dropped rapidly after days 2 to 4 of incubation at all temperatures. On day 4 of the culture, the pH was the lowest at 30 °C, followed by that at 35 °C, which was lower than that at 25 °C (p < 0.05).
The effects of SSF on the bioactive compound content of Radix Angelica gigas following L. buchneri inoculation are shown in Table 2. SSF increased the DPPH and ABTS radical scavenging activities and the contents of total phenols and flavonoids at all incubation temperatures compared with non-fermented conditions. The DPPH radical scavenging activity was significantly higher at 30 °C and 35 °C than that at 25 °C on days 2 and 4 of SSF (p < 0.05). The ABTS radical scavenging activity also showed a similar trend, with the highest at 30 °C, followed by that at 35 °C, which was higher than 25 °C on day 2 of SSF (p < 0.05). In addition, on day 8, the ABTS radical scavenging activity increased significantly at 35 °C compared with that at other temperatures (p < 0.05). The total phenolic contents were significantly higher at 30 °C and 35 °C than those at 25 °C on days 2–6 of SSF (p < 0.05). The total flavonoid content increased significantly at 30 °C and 35 °C compared with that at 25 °C on day 2 of fermentation (p < 0.05) and was the highest at 35 °C, followed by that at 30 °C and 25 °C on days 4 and 8 of SSF (p < 0.05).
Correlation analyses between bacterial growth or pH and antioxidant levels (DPPH, ABTS, phenol, and flavonoid) were performed under three temperature conditions (25 °C, 30 °C, and 35 °C) (Table 3). At all temperatures, DPPH measured during days 0–4 (hereafter referred to as the “0–4 day group”) exhibited a significant positive correlation with bacterial growth, whereas DPPH showed a significant negative correlation with growth during days 6–8 (hereafter referred to as the “6–8 day group”). The phenol levels measured at 30 °C and 35 °C were significantly positively correlated with growth in the 0–4 day group across all temperature conditions. In contrast, the phenol measured at 25 °C displayed a significant negative correlation with growth in the 6–8 day group at all temperatures, with the magnitude of the negative correlation diminishing as the temperature increased. The flavonoid concentrations measured at 30 °C and 35 °C also exhibited significant positive correlations with growth in the 0–4 day group across all temperatures, and the strength of these positive correlations increased with rising temperature. Conversely, in the 6–8 day group, the flavonoids measured at 30 °C and 35 °C showed significant negative correlations with growth across all temperatures, with stronger negative correlations observed at higher temperatures. Although the DPPH, phenol, and flavonoids demonstrated either positive or negative correlations with bacterial growth under specific temperature–time conditions, ABTS did not exhibit any statistically significant correlation with growth. Regarding pH, both the 0–4 day and 6–8 day groups showed significant negative correlations between pH and DPPH under most temperature conditions. The phenol measured at 30 °C and 35 °C exhibited a significant negative correlation with pH in the 0–4 day group across all temperatures, while the phenol measured at 25 °C displayed a significant negative correlation with pH during days 6–8 at every temperature. Moreover, most flavonoid measurements at 30 °C and 35 °C were significantly negatively correlated with pH in both the 0–4 day and 6–8 day groups across all temperatures. Similar to the growth correlation results, ABTS did not show any significant correlation with pH under any of the tested conditions.

3.3. Effects of SSF Using Different LAB on Antioxidant Activities of Radix Angelica gigas

L. acidophilus, L. buchneri, L. plantarum, and L. reuteri in the tested LAB showed enhanced growth in the screening experiment compared to the other strains (Table 1). To compare the growth in the SSF of Radix Angelica gigas, the four strains were cultured at 30 °C and 37 °C for 8 days (Figure 2). In particular, L. acidophilus and L. plantarum showed good growth on days 4 and 6 of SSF. Therefore, we selected these two strains to assess their effects in single- and multiple-culture (1:1, w/w) conditions. As shown in Figure 2, both LAB showed higher proliferation at 30 °C than at 37 °C on day 4 and 6 of SSF (p < 0.05). Therefore, these conditions (30 °C, days 4 and 6) were used for subsequent analyses. As shown in Figure 3, the multiple-strain culture showed significantly higher growth than the single-strain culture on day 4 of SSF (p < 0.05); however, on day 6, growth was significantly higher in both single-strain cultures than that in the mixed culture (p < 0.05).
The antioxidants of the fermented Radix Angelica gigas were enhanced by single- and multiple-strain probiotics (Figure 4). The DPPH radical scavenging activity was significantly higher in the cultures containing L. acidophilus than those in the L. planatrum and mixed strains on day 4 of SSF. Although the DPPH levels increased in an incubation-period-dependent manner in cultures with the L. planatrum and mixed strains, the culture with the mixed strains showed the highest growth on day 6 (p < 0.05). The ABTS radical scavenging activity increased continually after fermentation in all the inoculated forms and was significantly higher in the mixed form than in the single-strain inoculum on day 4 of fermentation (p < 0.05). However, on day 6, the ABTS level was highest in the mixed culture, followed by that in the L. acidophilus culture. The total phenolic and flavonoid contents also increased after fermentation in all the inoculated forms. The total phenolic content was significantly higher in the mixed form than that in the single-strain inoculum on days 4 and 6 of fermentation (p < 0.05). The total flavonoid content was significantly higher in the L. acidophilus culture than that in the mixed strain and L. plantarum culture day 6 of SSF (p < 0.05).

4. Discussion

Microbial fermentation is a crucial traditional processing technique in oriental medicine that alters the bioactive compound profiles of herbal materials, leading to enhanced intrinsic properties [6,22]. In the present study, we screened multiple probiotic strains, including Lactobacillus spp., Bacillus sp., and Saccharomyces sp. [23,24]. All the tested strains showed enhanced proliferation during the SSF of Radix Angelica gigas, with the LAB exhibiting more pronounced growth than B. subtilis and S. cerevisiae. These findings align with previous studies that have employed Lactobacillus species in the fermentation of oriental herbs, including L. acidophilus for Anoectochilus formosanus fermentation [25], L. buchneri for Triticum aestivum, Helianthus tuberosus and Smallanthus sonchifolius [26], L. plantarum for Rhizoma Atractylodis macrocephalae fermentation [27], and L. reuteri for Angelica sinensis fermentation [28]. Also, we found that L. buchneri exhibits superior growth performance in SSF compared to other LAB strains. Similar research results [29,30] reported that L. buchneri outgrows all other species within a short period on plant materials such as grass silage. The metabolic equipment of L. buchneri is unique as it is capable of converting lactic acid to acetic acid under aerobic as well as anaerobic conditions [31,32]. Additionally, L. buchneri is highly resistant against external perturbations such as the presence of competing microorganisms, oxygen, high lactic acid or ethanol concentrations, and low pH compared to other lactic acid bacteria [32].
The fermentation of herbal medicines requires appropriate conditions for various factors, such as the fermentation temperature, pH of the medium, types of microbes, inoculum concentration, and fermentation duration, which improve the quality and stability of the fermented products. In this study, L. buchneri, which showed the highest growth among screened strains, was selected for real-time monitoring of changes in the bioactive compounds in fermented Radix Angelica gigas, depending on the culture temperature and duration. The substrate for SSF was prepared by mixing the herb powder and distilled water (pH 7.0) in a 1:1 ratio based on the findings of our preliminary experiment. L. buchneri exhibited temperature- and time-dependent growth dynamics, with the highest growth observed at 30 °C on day 4 of incubation (p < 0.05). The optimal growth temperature for most LAB ranges from 30 to 45 °C [33]. Other studies have also shown that the optimal growth conditions for Lactobacillus spp. are 30–40 °C temperature and 5.5–6.2 pH [34]. A temperature of 30 °C falls within this optimal range and allows the optimal conditions for L. buchneri’s enzymes and cellular processes to function most efficiently, resulting in the highest growth rate, similar to many other LAB strains [35,36]. Consistent with our findings, previous studies have also reported similar optimal conditions. For instance, Slizewska and Chlebicz-Wójcik [37] reported the highest rate of proliferation of Lactobacillus spp. in SSF at 37 °C with a substrate powder-to-water ratio of 1:1.5 and a pH of 6.0. Moreover, maximal γ-aminobutyric acid production by L. buchneri was achieved at 30 °C and pH 5.0 after 48 h of fermentation [38]. The bile salt hydrolase (BSH) activity of this species was also found to be optimal at 37 °C and pH 7.0 [39], highlighting the need to tailor SSF parameters for specific functional outcomes.
Maintaining the optimal temperature during fermentation results in improved microbial growth and enzymatic activity, and consequently, the benefits of herbal fermentation are improved. Particularly, the release of antioxidative compounds was accelerated by the increased degradation of the plant cell walls, but extremely high or low temperatures reduced antioxidant activity during fermentation [35]. A fermentation temperature of 30 °C significantly increased polyphenols (followed by fermentation temperatures of 34 and 38 °C); the lowest levels are obtained at 24 and 42 °C in bush tea [40]. Also, the β-glucosidase activity of L. casei was maximal at 35 °C [41]. β-glucosidase activity during microbial fermentation causes the hydrolysis of phenolic glycosides and the release of free aglycones, which can have a high antioxidant activity. Our findings also showed that SSF significantly increased antioxidant activity including DPPH and ABTS radical scavenging capacity, phenolic content, and flavonoid content. These enhancements were more pronounced at 30 °C and 35 °C than at 25 °C. For instance, DPPH, ABTS, total phenols, and total flavonoid were increased by up to 230% on day 8 at 35 °C, 111% on day 2 at 30 °C, 137% on day 8 at 30 °C and 35 °C, and 133% on day at 35 °C, respectively, in the fermented herb compared with those in the non-fermented herb. The daily increments in DPPH, ABTS, total phenols, and total flavonoid were 3.97% per day for 4 days at 35 °C, 3.01% per day for 2 days at 30 °C, 0.002 mM GAE per day for 2 days at 30 °C and 35 °C, and 4.22 µg/mL QE per day for 2 days at 30 °C, respectively. These findings showed that antioxidant activity is most efficiently enhanced in the early fermentation period and continues to rise with extended incubation. This can occur due to the release and increase in the concentration of phenolic compounds and flavonoids during the early stages of fermentation and the depletion of substrates or inhibition by metabolites, as the fermentation process progresses and the environment shifts in the later stages [42,43,44]. This phenomenon is also confirmed in Table 3, where DPPH, total phenols, and total flavonoid show a significant positive correlation with cell growth in the early stage of fermentation (days 0–4) and a significant negative correlation thereafter. Previous other studies have similarly demonstrated that probiotic solid fermentation positively influences the antioxidant activity of oriental herbs [45]. For instance, SSF with L. plantarum and Enterococcus faecium markedly improved the production of the biological compounds of Astragalus membranaceus, such as polysaccharides, total saponins, and flavonoids [46]. Additionally, after fermentation by L. pentosus, the quercetin and kaempferol contents in extracts of Lespedeza cuneata G. Don increased by 242.9% and 266.7%, respectively [47]. The Bifidobacterium breve strain CCRC 14061 increased the daidzein and genistein contents in Puerariae Radix by 785% and 1010%, respectively [48]. Together, these findings suggest that combining probiotics and SSF improves the efficient production of bioactive substances during fermentation. Nevertheless, future studies are required to gain insights into the functional mechanisms of SSF to pave the way for the rational design of proper fermentation strategies for oriental herbal medicine.
Furthermore, we explored the potential of multi-strain probiotic fermentation, an emerging area of interest in microbial biotechnology. Although single strains are most commonly used for probiotic fermentation [49,50], multi-strain probiotics have shown promise to improve the utilization rate and increase the biotransformation efficiency of herbal medicines than single-strain fermentation [3,6,51]. Consistent with these studies, the present study showed improved efficiency of the combined strains in promoting biomaterial production and improving the antioxidant activities of the fermented Radix Angelica gigas. Multi-strain fermentation (such as L. acidophilus and L. plantarum) can increase the production of beneficial compounds and promote a synergistic effect between the bacterial strains, resulting in increased overall antioxidant activity [44,52,53]. The mixed cultures enhanced the growth of L. plantarum strains, which relate to the production of nutrients, such as vitamins, by other strains [54]. The antioxidant activity of multi-strain fermentation was enhanced due to an increase in the solubility of phenolic compounds in guava leaf tea and due to the production of more phenolic compounds with higher bioactivities, such as kaempferol and quercetin [55]. To harness the benefits of multi-strain fermentation, studies have used attempted combined fermentation with B. subtilis, Enterococcus faecalis, and S. cerevisiae for herbal mixture fermentation [56], L. rhamnosus and B. subtilis for Salvia miltiorrhiza Bunge fermentation [57], and Aspergillus niger and yeast for Polygonum cuspidatum root fermentation [58]. These findings reinforce the potential of multi-probiotic fermentation; however, despite these benefits, multi-strain probiotic SSF is still rare, possibly due to the complexities involved in microbial interaction and modulation of fermentation. Future studies to understand the optimization and utilization of multi-probiotic fermentation processes will be critical for the rational design of fermentation strategies in herbal medicine.

5. Conclusions

Although the properties of SSF changed in an incubation-temperature- and time-dependent manner in cultures with probiotic LAB, they significantly improved the antioxidant activity of Radix Angelica gigas (Danggui) during SSF. The DPPH and ABTS radical scavenging capacity, phenolic content, and flavonoid were enhanced by up to 230% on day 8 at 35 °C, 111% on day 2 at 30 °C, 137% on day 8 at 30 °C and 35 °C, and 133% on day at 35 °C, respectively, in fermented herb compared with those in non-fermented herb. These antioxidants, except ABTS, showed a significant positive correlation with bacterial growth during SSF. During the SSF of Radix Angelica gigas, multiple-strain probiotics were more effective in enhancing antioxidant activities compared with single-strain probiotics. Our results show that the peak of antioxidant increase was different depending on the fermentation conditions for the ingredients, but that the bioactive components of natural herbal medicines can be maximized through SSF. However, for the scientific design of standardized SSF in herbal medicine, further comprehensive studies on the correlated fermentation mechanisms and bioactive properties between herbal substrate–probiotic form-fermentative condition are needed.

Author Contributions

Conceptualization, Y.-K.H. and H.G.S.; methodology, H.G.S.; validation, Y.-K.H., A.Y.C. and H.G.S.; formal analysis, J.H.; investigation, A.Y.C.; resources, H.Y.; data curation, Y.-K.H. and H.G.S.; writing—original draft preparation, H.G.S.; writing—review and editing, J.H., Y.-K.H., A.Y.C. and H.Y.; visualization, Y.-K.H. and H.G.S.; supervision, H.G.S.; project administration, H.G.S.; funding acquisition, A.Y.C. and H.Y. All authors have read and agreed to the published version of the manuscript.

Funding

This work was supported by the Technology Development Program (S3350875) funded by the Ministry of SMEs and Startups (MSS, Republic of Korea) and was supported by IPET through Agriculture and Food Convergence Technologies Program for Research Manpower Development Program or Project, funded by MAFRA (grant number RS-2024-00400922)].

Institutional Review Board Statement

Not applicable.

Informed Consent Statement

Not applicable.

Data Availability Statement

The original contributions presented in the study are included in the article; further inquiries can be directed to the corresponding author.

Conflicts of Interest

Ah Yeong Choi and Hyouk Yoon are employees of Pet21 Co., Ltd. The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

Abbreviations

The following abbreviations are used in this manuscript:
SSFSolid-state fermentation
ABTS2,2′-Azino-bis(3-ethylbenzothiazoline-6-sulfonic acid)
DPPH2,2-Diphenyl-1-picrylhydrazyl
GAEGallic acid equivalents
QEQuercetin equivalent
LABLactic acid bacteria
CFUColony-forming unit

References

  1. Park, Y.; Park, P.S.; Jeong, D.H.; Sim, S.; Kim, N.; Park, H.; Jeon, K.S.; Um, Y.; Kim, M.-J. The characteristics of the growth and the active compounds of Angelica gigas Nakai in cultivation sites. Plants 2020, 9, 823. [Google Scholar] [CrossRef]
  2. He, Z.; Wang, Y.; Chen, Y.; Geng, F.; Jiang, Z.; Li, X. Angelica gigas Nakai: An overview on its chemical composition and pharmacological activity. Biochem. Syst. Ecol. 2023, 111, 104717. [Google Scholar] [CrossRef]
  3. Zhang, X.; Miao, Q.; Pan, C.; Yin, J.; Wang, L.; Qu, L.; Yin, Y.; Wei, Y. Research advances in probiotic fermentation of Chinese herbal medicines. iMeta 2023, 2, e93. [Google Scholar] [CrossRef]
  4. Yang, B.; Xie, Y.; Guo, M.; Rosner, M.H.; Yang, H.; Ronco, C. Nephrotoxicity and Chinese herbal medicine. Clin. J. Am. Soc. Nephrol. 2018, 13, 1605–1611. [Google Scholar] [CrossRef] [PubMed]
  5. Charen, E.; Harbord, N. Toxicity of herbs, vitamins, and supplements. Adv. Chronic Kidney Dis. 2020, 27, 67–71. [Google Scholar] [CrossRef] [PubMed]
  6. Li, L.; Wang, L.; Fan, W.; Jiang, Y.; Zhang, C.; Li, J.; Peng, W.; Wu, C. The application of fermentation technology in traditional Chinese medicine: A review. Am. J. Chin. Med. 2020, 48, 899–921. [Google Scholar] [CrossRef]
  7. Wu, T.; Wang, N.; Zhang, Y.; Xu, X. Advances in the study on microbial fermentation and transformation of traditional Chinese medicine. Afr. J. Microbiol. Res. 2013, 7, 1644–1650. [Google Scholar]
  8. Bose, S.; Song, M.-Y.; Nam, J.-K.; Lee, M.-J.; Kim, H. In vitro and in vivo protective effects of fermented preparations of dietary herbs against lipopolysaccharide insult. Food Chem. 2012, 134, 758–765. [Google Scholar] [CrossRef]
  9. Ma, J.; Wang, J.; Wan, Y.; Wang, S.; Jiang, C. Probiotic-fermented traditional Chinese herbal medicine, a promising approach to maintaining the intestinal microecology. J. Ethnopharmacol. 2025, 337, 118815. [Google Scholar] [CrossRef]
  10. Lee, J.-J.; Kwon, H.; Lee, J.-H.; Kim, D.-G.; Jung, S.-H.; Ma, J.Y. Fermented Soshiho-tang with Lactobacillus plantarum enhances the antiproliferative activity in vascular smooth muscle cell. BMC Complement. Altern. Med. 2014, 14, 78. [Google Scholar] [CrossRef]
  11. Garrido-Galand, S.; Asensio-Grau, A.; Calvo-Lerma, J.; Heredia, A.; Andrés, A. The potential of fermentation on nutritional and technological improvement of cereal and legume flours: A review. Food Res. Int. 2021, 145, 110398. [Google Scholar] [CrossRef] [PubMed]
  12. Canoy Postigo, L.O.; Jacobo-Velázquez, D.A.; Guajardo-Flores, D.; Amezquita, L.E.G.; García-Cayuela, T. Solid-state fermentation for enhancing the nutraceutical content of agrifood byproducts: Recent advances and its industrial feasibility. Food Biosci. 2021, 41, 100926. [Google Scholar]
  13. Arora, S.; Rani, R.; Ghosh, S. Bioreactors in solid state fermentation technology: Design, applications and engineering aspects. J. Biotechnol. 2018, 269, 16–34. [Google Scholar] [CrossRef]
  14. Lee, H.-S.; Kim, M.-R.; Park, Y.; Park, H.J.; Chang, U.J.; Kim, S.Y.; Suh, H.J. Fermenting red ginseng enhances its safety and efficacy as a novel skin care anti-aging ingredient: In vitro and animal study. J. Med. Food 2012, 15, 1015–1023. [Google Scholar] [CrossRef]
  15. Carneiro, A.A.J.; Ferreira, I.C.F.R.; Duenas, M.; Barros, L.; Silva, R.; Gomes, E.; Santos-Buelga, C. Chemical composition and antioxidant activity of dried powder formulations of Agaricus blazei and Lentinus edodes. Food Chem. 2013, 138, 2168–2173. [Google Scholar] [CrossRef] [PubMed]
  16. Re, R.; Pellegrini, N.; Proteggente, A.; Pannala, A.; Yang, M.; Rice-Evans, C. Antioxidant activity applying an improved ABTS radical cation decolorization assay. Free Radic. Biol. Med. 1999, 26, 1231–1237. [Google Scholar] [CrossRef] [PubMed]
  17. Prior, R.L.; Wu, X.; Schaich, K. Standardized methods for the determination of antioxidant capacity and phenolics in foods and dietary supplements. J. Agric. Food Chem. 2005, 53, 4290–4302. [Google Scholar] [CrossRef]
  18. Folin, O.; Ciocalteu, V. On tyrosine and tryptophane determinations in proteins. J. Biol. Chem. 1927, 73, 627–650. [Google Scholar] [CrossRef]
  19. Park, Y.S.; Jung, S.T.; Kang, S.G.; Heo, B.K.; Arancibia-Avila, P.; Toledo, F.; Drzewiecki, J.; Namiesnik, J.; Gorinstein, S. Antioxidants and proteins in ethylene-treated kiwifruits. Food Chem. 2008, 107, 640–648. [Google Scholar] [CrossRef]
  20. Saeed, N.; Khan, M.R.; Shabbir, M. Antioxidant activity, total phenolic and total flavonoid contents of whole plant extracts Torilis leptophylla L. BMC Complement. Altern. Med. 2012, 12, 221. [Google Scholar]
  21. R Core Team. R. A Language and Environment for Statistical Computing; R Foundation for Statistical Computing: Vienna, Austria, 2024. [Google Scholar]
  22. Lixia, Z.; Gao, W.; Wang, H. Review of traditional Chinese medicine processed by fermentation. China J. Chin. Mater. Medica 2012, 37, 3695–3700. [Google Scholar]
  23. Kim, S.-K.; Guevarra, R.B.; Kim, Y.-T.; Kwon, J.; Kim, H.; Cho, J.H.; Kim, H.B.; Lee, J.-H. Role of probiotics in human gut microbiome-associated diseases. J. Microbiol. Biotechnol. 2019, 29, 1335–1340. [Google Scholar] [CrossRef]
  24. Anee, I.J.; Alam, S.; Begum, R.A.; Shahjahan, R.M.; Khandaker, A.M. The role of probiotics on animal health and nutrition. J. Basic. Appl. Zool. 2021, 82, 52. [Google Scholar] [CrossRef]
  25. Ng, C.-C.; Wang, C.-Y.; Wang, Y.-P.; Tzeng, W.-S.; Shyu, Y.-T. Lactic acid bacterial fermentation on the production of functional antioxidant herbal Anoectochilus formosanus Hayata. J. Biosci. Bioeng. 2011, 111, 289–293. [Google Scholar] [CrossRef] [PubMed]
  26. Kang, Y.-M.; Hong, C.-H.; Kang, S.-H.; Seo, D.-S.; Kim, S.-O.; Lee, H.-Y.; Sim, H.-J.; An, H.-J. Anti-photoaging effect of plant extract fermented with Lactobacillus buchneri on CCD-986 fibroblasts and HaCaT keratinocytes. J. Funct. Biomater. 2020, 11, 3. [Google Scholar] [CrossRef]
  27. Wang, J.-H.; Bose, S.; Kim, H.-G.; Han, K.-S.; Kim, H. Fermented Rhizoma Atractylodis macrocephalae alleviates high fat diet-induced obesity in association with regulation of intestinal permeability and microbiota in rats. Sci. Rep. 2015, 5, 8391. [Google Scholar] [CrossRef]
  28. Huang, C.-C.; Lai, T.-H.; Huang, R.-Y.; Su, K.-W.; Lai, S.-R.; Lan, A. Effect of an herbal preparation fermented by Lactobacillus reuteri LR107 in preventing periodontal inflammation in an experimental gingivitis model. Asian J. Complement. Altern. Med. 2014, 2, 12–18. [Google Scholar]
  29. Eikmeyer, F.G.; Kofinger, P.; Poschenel, A.; Junemann, S.; Zakrzewski, M.; Heinl, S.; Mayrhuber, E.; Grabherr, R.; Puhler, A.; Schwab, H.; et al. Metagenome analyses reveal the influence of the inoculant Lactobacillus buchneri CD034 on the microbial community involved in grass ensiling. J. Biotechnol. 2013, 167, 334–343. [Google Scholar] [CrossRef]
  30. Eikmeyer, F.G.; Heinl, S.; Marx, H.; Puhler, A.; Grabherr, R.; Schluter, A. Identification of oxygen-responsive transcripts in the silage inoculant Lactobacillus buchneri CD034 by RNA sequencing. PLoS ONE 2015, 10, e0134149. [Google Scholar] [CrossRef]
  31. Oude Elferink, S.J.; Krooneman, J.; Gottschal, J.C.; Spoelstra, S.F.; Faber, F.; Driehuis, F. Anaerobic conversion of lactic acid to acetic acid and 1,2-propanediolby Lactobacillus buchneri. Appl. Environ. Microbiol. 2001, 67, 125–132. [Google Scholar] [CrossRef]
  32. Heinl, S.; Grabherr, R. Systems biology of robustness and flexibility: Lactobacillus buchneri—A show case. J. Biotechnol. 2017, 257, 61–69. [Google Scholar] [CrossRef] [PubMed]
  33. Terpou, A.; Papadaki, A.; Lappa, I.K.; Kachrimanidou, V.; Bosnea, L.A.; Kopsahelis, N. Probiotics in Food Systems: Significance and Emerging Strategies towards Improved Viability and Delivery of Enhanced Beneficial Value. Nutrients 2019, 11, 1591. [Google Scholar] [CrossRef] [PubMed]
  34. König, H.; Berkelmann-Löhnertz, B. Maintenance of wine-associated microorganisms. In Biology of Microorganisms on Grapes, in Must and in Wine; König, H., Gottfried, U., Fröhlich, J., Eds.; Springer: Cham, Switzerland, 2017; pp. 549–572. ISBN 9783319600215. [Google Scholar]
  35. Hur, S.J.; Lee, S.Y.; Kim, Y.C.; Choi, I.; Kim, G.B. Effect of fermentation on the antioxidant activity in plant-based foods. Food Chem. 2014, 160, 346–356. [Google Scholar] [CrossRef]
  36. Sionek, B.; Szydłowska, A.; Skowska, M.T.; Kołożyn-Krajewska, D. The impact of physicochemical conditions on lactic acid bacteria survival in food products. Fermentation 2024, 10, 298. [Google Scholar] [CrossRef]
  37. Slizewska, K.; Chlebicz-Wójcik, A. Growth kinetics of probiotic Lactobacillus strains in the alternative, cost-efficient semi-solid fermentation medium. Biology 2020, 9, 423. [Google Scholar] [CrossRef] [PubMed]
  38. Cho, Y.R.; Chang, J.Y.; Chang, H.C. Production of γ-Aminobutyric Acid (GABA) by Lactobacillus buchneri Isolated from Kimchi and its Neuroprotective Effect on Neuronal Cells. J. Microbiol. Biotechnol. 2007, 17, 104–109. [Google Scholar]
  39. Sridevi, N.; Vishwe, P.; Prabhune, A. Hypocholesteremic effect of bile salt hydrolase from Lactobacillus buchneri ATCC 4005. Food Res. Int. 2009, 42, 516–520. [Google Scholar] [CrossRef]
  40. Hlahla, L.N.; Mudau, F.N.; Mariga, I.K. Effect of fermentation temperature and time on the chemical composition of bush tea (Athrixia phylicoides DC.). J. Med. Plant Res. 2010, 4, 824–829. [Google Scholar]
  41. Coulon, S.; Chemardin, P.; Gueguen, Y.; Arnaud, A.; Galzy, P. Purification and characterization of an intracellular β-glucosidase from Lactobacillus casei ATCC 393. Appl. Biochem. Biotechnol. 1998, 74, 105–114. [Google Scholar] [CrossRef]
  42. Erskine, E.; Ozkan, G.; Lu, B.; Capanoglu, E. Effects of fermentation process on the antioxidant capacity of fruit byproducts. ACS Omega 2023, 8, 4543–4553. [Google Scholar] [CrossRef]
  43. Sarıta, S.; Portocarrero, A.C.M.; López, J.M.M.; Lombardo, M.; Koch, W.; Raposo, A.; El-Seedi, H.R.; Alves, J.L.B.; Esatbeyoglu, T.; Sercan Kara, S.; et al. The impact of fermentation on the antioxidant activity of food products. Molecules 2024, 29, 3941. [Google Scholar] [CrossRef]
  44. Zhao, Y.-S.; Eweys, A.S.; Zhang, J.-Y.; Zhu, Y.; Bai, J.; Darwesh, O.M.; Zhang, H.-B.; Xiao, X. Fermentation affects the antioxidant activity of plant-based food material through the release and production of bioactive components. Antioxidants 2021, 10, 2004. [Google Scholar] [CrossRef] [PubMed]
  45. Lee, M.-H.; Lee, Y.-C.; Kim, S.-S.; Hong, H.-D.; Kim, K.-T. Quality and antioxidant activity of ginseng seed processed by fermentation strains. J. Ginseng Res. 2015, 39, 178–182. [Google Scholar] [CrossRef]
  46. Qiao, H.; Zhang, X.; Shi, H.; Song, Y.; Bian, C.; Guo, A. Assessment of the physicochemical properties and bacterial composition of Lactobacillus plantarum and Enterococcus faecium-fermented Astragalus membranaceus using single molecule, real-time sequencing technology. Sci. Rep. 2018, 8, 11862. [Google Scholar] [CrossRef]
  47. Seong, J.S.; Xuan, S.H.; Park, S.H.; Lee, K.S.; Park, Y.M.; Park, S.N. Antioxidative and antiaging activities and component analysis of Lespedeza cuneata G. Don extracts fermented with Lactobacillus pentosus. J. Microbiol. Biotechnol. 2017, 27, 1961–1970. [Google Scholar] [CrossRef]
  48. Wen, K.C.; Lin, S.-P.; Yu, C.-P.; Chen, H.-M. Comparison of Puerariae Radix and its hydrolysate on stimulation of hyaluronic acid production in NHEK cells. Am. J. Chin. Med. 2010, 38, 143–155. [Google Scholar] [CrossRef] [PubMed]
  49. Cao, H.; Chen, X.; Jassbi, A.R.; Xiao, J. Microbial biotransformation of bioactive flavonoids. Biotechnol. Adv. 2015, 33, 214–223. [Google Scholar] [CrossRef] [PubMed]
  50. Hussain, A.; Bose, S.; Wang, J.-H.; Yadav, M.K.; Mahajan, G.B.; Kim, H. Fermentation, a feasible strategy for enhancing bioactivity of herbal medicines. Food Res. Int. 2016, 81, 1–16. [Google Scholar] [CrossRef]
  51. Chapman, C.M.C.; Gibson, G.R.; Rowland, I. Health benefits of probiotics: Are mixtures more effective than single strains? Eur. J. Nutr. 2011, 50, 1–17. [Google Scholar] [CrossRef]
  52. Liu, H.; Ni, Y.; Qun Yu, Q.; Fan, L. Evaluation of co-fermentation of L. plantarum and P. kluyveri of a plant-based fermented beverage: Physicochemical, functional, and sensory properties. Food Res. Int. 2023, 172, 113060. [Google Scholar] [CrossRef]
  53. Li, X.; Gao, W.; Wang, L.; Chen, Y.; Cai, Z.; Wu, D.; Chen, N.; Jiang, Q.; Zheng, Z.; Zhu, J.; et al. Co-fermentation of Lactobacillus plantarum and Lactobacillus casei improves in vitro antioxidant capacity and quality of apple juice. Fermentation 2025, 11, 161. [Google Scholar] [CrossRef]
  54. Hashemi, S.M.B.; Jafarpour, D. Fermentation of bergamot juice with Lactobacillus plantarum strains in pure and mixed fermentations: Chemical composition, antioxidant activity and sensorial properties. LWT Food Sci. Technol. 2020, 131, 109803. [Google Scholar] [CrossRef]
  55. Wang, L.; Luo, Y.; Wu, Y.; Liu, Y.; Wu, Z. Fermentation and complex enzyme hydrolysis for improving the total soluble phenolic contents, flavonoid aglycones contents and bio-activities of guava leaves tea. Food Chem. 2018, 264, 189–198. [Google Scholar] [CrossRef] [PubMed]
  56. Li, Y.; Sun, T.; Hong, Y.; Qiao, T.; Wang, Y.; Li, W.; Tang, S.; Yang, X.; Li, J.; Li, X.; et al. Mixture of five fermented herbs (Zhihuasi Tk) alters the intestinal microbiota and promotes the growth performance in piglets. Front. Microbiol. 2021, 12, 725196. [Google Scholar] [CrossRef] [PubMed]
  57. Su, L.; Su, Y.; An, Z.; Zhang, P.; Yue, Q.; Zhao, C.; Sun, X.; Zhang, S.; Liu, X.; Li, K.; et al. Fermentation products of Danshen relieved dextran sulfate sodium-induced experimental ulcerative colitis in mice. Sci. Rep. 2021, 11, 16210. [Google Scholar] [CrossRef]
  58. Jin, S.; Luo, M.; Wang, W.; Zhao, C.; Gu, C.; Li, C.; Zu, Y.; Fu, Y.; Guan, Y. Biotransformation of polydatin to resveratrol in Polygonum cuspidatum roots by highly immobilized edible Aspergillus niger and yeast. Bioresour. Technol. 2013, 136, 766–770. [Google Scholar] [CrossRef]
Fermentation 11 00342 g001
Figure 1. Effects of culture temperature and duration on the growths of L. buchneri (A) and the pHs (B) in SSF of Radix Angelica gigas. a,b,c Means in the same period with different superscripts are significantly different (p < 0.05). 25 °C, 30 °C, and 35 °C mean temperature of incubation.
Figure 1. Effects of culture temperature and duration on the growths of L. buchneri (A) and the pHs (B) in SSF of Radix Angelica gigas. a,b,c Means in the same period with different superscripts are significantly different (p < 0.05). 25 °C, 30 °C, and 35 °C mean temperature of incubation.
Fermentation 11 00342 g001
Fermentation 11 00342 g002
Figure 2. Growth of L. acidophilus, L. reuteri, L. buchneri, and L. plantarum under different culture temperatures during the periods of SSF. a,b,c,d Means in the same period with different superscripts are significantly different (p < 0.05).
Figure 2. Growth of L. acidophilus, L. reuteri, L. buchneri, and L. plantarum under different culture temperatures during the periods of SSF. a,b,c,d Means in the same period with different superscripts are significantly different (p < 0.05).
Fermentation 11 00342 g002
Fermentation 11 00342 g003
Figure 3. Effects of single- and mixed-culture solid-state fermentation using L. acidophilus and L. plantarum on cell growth at different incubation periods. a,b Means in the same period with different superscripts are significantly different (p < 0.05). Mix, the mixed culture of L. acidophilus and L. plantarum (1:1 ratio, w/w).
Figure 3. Effects of single- and mixed-culture solid-state fermentation using L. acidophilus and L. plantarum on cell growth at different incubation periods. a,b Means in the same period with different superscripts are significantly different (p < 0.05). Mix, the mixed culture of L. acidophilus and L. plantarum (1:1 ratio, w/w).
Fermentation 11 00342 g003
Fermentation 11 00342 g04aFermentation 11 00342 g04b
Figure 4. Effects of single- and multiple-strain culture SSF using L. acidophilus and L. plantarum on the bioactivity potential of Radix Angelica gigas. (A) DPPH radical scavenging activity (%), (B) ABTS radical scavenging activity (%), (C) total phenolic content (mM GAE), and (D) total flavonoid content (QE µg/mL). a,b Means in the same period with different superscripts are significantly different (p < 0.05).
Figure 4. Effects of single- and multiple-strain culture SSF using L. acidophilus and L. plantarum on the bioactivity potential of Radix Angelica gigas. (A) DPPH radical scavenging activity (%), (B) ABTS radical scavenging activity (%), (C) total phenolic content (mM GAE), and (D) total flavonoid content (QE µg/mL). a,b Means in the same period with different superscripts are significantly different (p < 0.05).
Fermentation 11 00342 g04aFermentation 11 00342 g04b
Table 1. Bacterial screening for solid-state fermentation of Angelica gigas.
Table 1. Bacterial screening for solid-state fermentation of Angelica gigas.
L. rhamnosusL. acidophilusL. buchneriL. plantarumL. reuteriB. subtilisS. cerevisiae
Bacterial growth (1)2.80 ± 0.36 f627.00 ± 24.64 b706.76 ± 51.32 a630.00 ± 20.00 b453.00 ± 15.72 c58.00 ± 20.00 de37.33 ± 13.01 e
pH change (2)0.35 ± 0.08 c1.23 ± 0.11 a1.02 ± 0.04 b1.27 ± 0.02 a1.25 ± 0.01 a0.42 ± 0.15 c0.39 ± 0.06 c
(1) Unit is × 105 CFU/g; (2) Differences before and after culture; a–f Means with different superscripts in a row differ significantly (p < 0.05).
Table 2. Changes in bioactivity potential of Radix Angelica gigas following SSF using L. buchneri at different culture periods and temperatures.
Table 2. Changes in bioactivity potential of Radix Angelica gigas following SSF using L. buchneri at different culture periods and temperatures.
TemperaturePeriod of Incubation (Days)
02468
DPPH radical scavenging activity (%)
25 °C17.26 ± 1.61 Ae20.02 ± 1.72 Bd23.24 ± 1.55 Bc33.19 ± 1.88 Ab36.32 ± 1.79 Aa
30 °C18.10 ± 1.14 Ad25.68 ± 1.83 Ac33.45 ± 1.45 Ab33.49 ± 1.79 Ab38.02 ± 1.56 ABa
35 °C17.13 ± 1.31 Ad26.75 ± 1.62 Ac33.00 ± 1.82 Ab33.09 ± 1.67 Ab39.45 ± 1.68 Aa
ABTS radical scavenging activity (%)
25 °C54.73 ± 0.30 Aa56.42 ± 0.37 Ca56.52 ± 0.54 Aa55.39 ± 1.07 Aa55.66 ± 0.85 Ba
30 °C54.09 ± 0.30 Ab60.12 ± 0.18 Aa55.70 ± 0.99 Ab55.53 ± 0.73 Ab55.19 ± 0.47 Bb
35 °C54.93 ± 0.30 Ab58.24 ± 1.14 Ba56.25 ± 0.67 Aab56.61 ± 0.18 Aab58.15 ± 0.95 Aa
Total phenolic content (mM gallic acid equivalent, mM GAE)
25 °C0.26 ± 0.001 Ac0.27 ± 0.005 Bc0.27 ± 0.002 Cc0.33 ± 0.006 Bb0.38 ± 0.006 Aa
30 °C0.27 ± 0.001 Ae0.31 ± 0.003 Ad0.34 ± 0.001 Bc0.35 ± 0.007 Ab0.37 ± 0.007 Aa
35 °C0.27 ± 0.008 Ac0.31 ± 0.005 Ab0.35 ± 0.006 Aa0.36 ± 0.013 Aa0.37 ± 0.020 Aa
Total flavonoid content (μg/mL quercetin equivalent, μg/mL QE)
25 °C46.93 ± 1.70 Ac48.74 ± 2.31 Bb48.89 ± 0.89 Cb55.78 ± 1.92 Aa57.26 ± 1.28 ca
30 °C46.15 ± 1.85 Ac54.59 ± 2.33 Ab56.89 ± 1.00 Bab56.52 ± 0.94 Aab59.11 ± 1.00 Ba
35 °C47.30 ± 1.89 Ad53.93 ± 0.64 Ac59.48 ± 2.31 Aab57.63 ± 1.70 Abc63.19 ± 0.64 Aa
A,B,C Means in the same period with different superscripts are significantly different (p < 0.05). a,b,c,d,e Means within the same temperature followed by different superscript letters are significantly different (p < 0.05).
Table 3. Correlation between bacterial growth and pH under different temperature conditions.
Table 3. Correlation between bacterial growth and pH under different temperature conditions.
Antioxidant
Activity
Assay		Temperature GrowthpH
25 °C30 °C35 °C25 °C30 °C35 °C
0–4 d6–8 d0–4 d6–8 d0–4 d6–8 d0–4 d6–8 d0–4 d6–8 d0–4 d6–8 d
DPPH25 °C0.762 (0.017)−0.963 (0.002)0.784 (0.012)−0.942 (0.005)0.782 (0.013)−0.899 (0.015)−0.839 (0.005)−0.949 (0.004)−0.78 (0.013)−0.912 (0.011)−0.835 (0.005)−0.888 (0.018)
30 °C0.876 (0.002)−0.925 (0.008)0.892 (0.001)−0.895 (0.016)0.892 (0.001)−0.81 (0.051)−0.932 (0)−0.897 (0.015)−0.888 (0.001)−0.833 (0.04)−0.928 (0)−0.805 (0.054)
35 °C0.812 (0.008)−0.992 (0)0.822 (0.007)−0.969 (0.001)0.831 (0.005)−0.951 (0.004)−0.878 (0.002)−0.989 (0)−0.822 (0.007)−0.942 (0.005)−0.869 (0.002)−0.929 (0.007)
ABTS25 °C0.503 (0.168)−0.265 (0.612)0.521 (0.151)−0.09 (0.865)0.528 (0.144)−0.136 (0.798)−0.592 (0.093)−0.165 (0.755)−0.522 (0.15)−0.094 (0.859)−0.587 (0.097)−0.063 (0.906)
30 °C−0.324 (0.395)0.241 (0.646)−0.305 (0.425)0.217 (0.679)−0.292 (0.446)0.265 (0.611)0.203 (0.601)0.272 (0.602)0.304 (0.427)0.221 (0.675)0.213 (0.583)0.251 (0.631)
35 °C−0.055 (0.887)−0.63 (0.18)−0.048 (0.902)−0.723 (0.104)−0.027 (0.945)−0.753 (0.084)−0.049 (0.901)−0.686 (0.132)0.05 (0.898)−0.747 (0.088)−0.035 (0.928)−0.75 (0.086)
Phenol25 °C0.511 (0.16)−0.912 (0.011)0.517 (0.154)−0.982 (0)0.522 (0.15)−0.967 (0.002)−0.557 (0.119)−0.963 (0.002)−0.519 (0.152)−0.981 (0.001)−0.549 (0.126)−0.981 (0.001)
30 °C0.872 (0.002)−0.604 (0.204)0.879 (0.002)−0.487 (0.328)0.888 (0.001)−0.546 (0.262)−0.926 (0)−0.576 (0.232)−0.878 (0.002)−0.477 (0.338)−0.92 (0)−0.484 (0.33)
35 °C0.854 (0.003)−0.381 (0.456)0.858 (0.003)−0.547 (0.261)0.871 (0.002)−0.562 (0.246)−0.91 (0.001)−0.499 (0.314)−0.86 (0.003)−0.609 (0.199)−0.902 (0.001)−0.636 (0.175)
Flavonoid25 °C0.473 (0.198)−0.578 (0.229)0.494 (0.177)−0.582 (0.225)0.498 (0.172)−0.449 (0.372)−0.573 (0.107)−0.534 (0.275)−0.485 (0.186)−0.503 (0.309)−0.561 (0.116)−0.458 (0.361)
30 °C0.663 (0.052)−0.91 (0.012)0.679 (0.044)−0.823 (0.044)0.686 (0.041)−0.841 (0.036)−0.743 (0.022)−0.867 (0.025)−0.677 (0.045)−0.808 (0.052)−0.737 (0.023)−0.784 (0.065)
35 °C0.831 (0.006)−0.924 (0.009)0.836 (0.005)−0.937 (0.006)0.848 (0.004)−0.921 (0.009)−0.889 (0.001)−0.948 (0.004)−0.834 (0.005)−0.915 (0.011)−0.88 (0.002)−0.914 (0.011)
The values represent the correlation coefficients, with the p-values shown in parentheses.
Disclaimer/Publisher’s Note: The statements, opinions and data contained in all publications are solely those of the individual author(s) and contributor(s) and not of MDPI and/or the editor(s). MDPI and/or the editor(s) disclaim responsibility for any injury to people or property resulting from any ideas, methods, instructions or products referred to in the content.

Share and Cite

MDPI and ACS Style

Heo, J.; Ham, Y.-K.; Choi, A.Y.; Yoon, H.; Sung, H.G. Lactic Acid Bacteria as Probiotics Improve Bioactive Compounds in Radix Angelica gigas (Danggui) via Solid-State Fermentation. Fermentation 2025, 11, 342. https://doi.org/10.3390/fermentation11060342

AMA Style

Heo J, Ham Y-K, Choi AY, Yoon H, Sung HG. Lactic Acid Bacteria as Probiotics Improve Bioactive Compounds in Radix Angelica gigas (Danggui) via Solid-State Fermentation. Fermentation. 2025; 11(6):342. https://doi.org/10.3390/fermentation11060342

Chicago/Turabian Style

Heo, Jeong, Youn-Kyung Ham, Ah Yeong Choi, Hyouk Yoon, and Ha Gyun Sung. 2025. "Lactic Acid Bacteria as Probiotics Improve Bioactive Compounds in Radix Angelica gigas (Danggui) via Solid-State Fermentation" Fermentation 11, no. 6: 342. https://doi.org/10.3390/fermentation11060342

APA Style

Heo, J., Ham, Y.-K., Choi, A. Y., Yoon, H., & Sung, H. G. (2025). Lactic Acid Bacteria as Probiotics Improve Bioactive Compounds in Radix Angelica gigas (Danggui) via Solid-State Fermentation. Fermentation, 11(6), 342. https://doi.org/10.3390/fermentation11060342

Note that from the first issue of 2016, this journal uses article numbers instead of page numbers. See further details here.

Article Metrics

Back to TopTop