Inulin, a prebiotic utilized in the food and pharmaceutical industries, promotes the growth of beneficial bacteria in the colon, thereby enhancing human health. Although inulin is commercially produced from chicory and artichoke, Inula helenium roots offer a high potential for inulin production. The aim of this study is to investigate the prebiotic activity of inulin (inulin-P) from I. helenium roots on Lactobacillus rhamnosus, as well as its ability to produce synbiotic microcapsules and the effects on probiotic viability during freeze-drying, in vitro gastrointestinal (GI) digestion, and storage. First, the effect of inulin-P on L. rhamnosus viability and short-chain fatty acid (SCFA) production was compared to other commonly utilized prebiotics. The findings revealed that inulin-P remarkably promoted the growth and SCFA yield of L. rhamnosus for 48 h of fermentation and 28 days of storage. Then, L. rhamnosus was encapsulated with inulin-P and commercial inulin to compare its survival throughout storage and the GI tract. Inulin-P microcapsules outperformed in terms of viability during storage (7.98 log CFU/g after 30 days at 4°C). Furthermore, inulin-P microcapsules were heat-resistant and protected L. rhamnosus from GI conditions, resulting in a high survival rate (89.52%) following large intestine simulation, which is ideal for increasing customer benefits. Additionally, inulin-P microcapsules exhibited similar physical characteristics to commercial inulin. Consequently, this study revealed that inulin-P, which is easy to produce, low-cost, and has industrial application potential, could be used as a good carrier for the synbiotic encapsulation of L. rhamnosus. PRACTICAL APPLICATION: Inulin is a prebiotic that promotes the activity and growth of beneficial bacteria in the human gut. Although commercial inulin is currently produced from chicory root and artichoke, Inula helenium root is a potential raw material for inulin production. In this study, inulin was produced from I. helenium roots with a low-cost and easy production method, and it was determined that this inulin was an effective carrier in the synbiotic encapsulation of L. rhamnosus. This inulin exhibits superior prebiotic activity and encapsulation efficiency compared to commercial inulins like Orafti® GR and HPX and can be easily integrated into industrial production.

The growth of Lactobacillus plantarum, a member of the Lactobacillus genus, which plays a crucial role in the bacterial microbiome of the gut, is significantly influenced by manganese ions. They can be safely delivered to the intestines by exploiting the chelating abilities of lactoferrin. The aim of this work was to encapsulate lactoferrin saturated with manganese ions (MnLf) in a system based on the Eudragit® RS polymer to protect protein from degradation and manganese release in the gastric environment. The entrapment efficiency was satisfactory, reaching about 95%, and most importantly, manganese ions were not released during microparticles (MPs) formation. The release profile of the protein from the freshly prepared MPs was sustained, with less than 15% of the protein released within the first hour. To achieve similar protein release efficiency, freeze-drying was carried out in the presence of 10% (w/v) mannitol as a cryoprotectant for MPs frozen at -20 °C. MPs with encapsulated MnLf exhibited prebiotic activity towards Lactobacillus plantarum. More importantly, the presence of equivalent levels of manganese ions in free form in the medium, as well as chelating by lactoferrin encapsulated in MPs, had a similar impact on stimulating bacterial growth. This indicates that the bioavailability of manganese ions in our prepared system is very good.

This study describes the extraction and characterization of the hemicellulosic autohydrolysates (HAHs) derived from rice straw (RS) and vascular aquatic weeds like Typha angustifolia (TA) and Ceretophyllum demersum (CD). It further explores their capacity to sustain the proliferation of selected lactic acid bacteria (i.e., prebiotic activity) isolated from milk samples. To fractionate HAH from RS, TA and CD hot water extraction (HWE) method was used and RS, TA, and CD biomasses yielded 6.8, 4.99 and 2.98% of HAH corresponding to the hemicellulose extraction efficiencies of 26.15 ± 0.8%, 23.76 ± 0.6%, and 18.62 ± 0.4% respectively. The chemical characterization of HAH concentrates through HPLC showed that they comprised galactose, arabinose, xylose and glucose. The total phenol content of the RS, TA and CD-derived HAH concentrates were 37.53, 56.78 and 48.08 mg GAE/g. The five lactic acid bacteria (LAB) isolates Q1B, Q2A, Q3B, G1C and G2B selected for prebiotic activity assays generated mixed responses with the highest growth in RS-HAH for Q2A and the least in TA-HAH for Q3B. Further, the isolates Q2A, Q3B, G1C, and G2B, which showed the highest growth performance, were identified through MALDI-TOF and 16S rRNA sequencing as Lactobacillus brevis. All the tested LAB isolates showed diauxic growth in crude HAH preparations to maximize the utilization of carbon resources for their proliferation. This suggests that the selected LAB isolates are efficient degraders of hemicellulosic sugars. This paves the way for the valorization of lignocellulosic biomass to produce prebiotic hemicellulosic autohydrolysate and consequently enhances environmental sustainability by improving resource efficiency.

Paotianxiong (PTX) is a processing product of Aconitum carmichaelii Debx., often used as a tonic food daily. However, the structure and activity of the polysaccharide component that plays a major role still need to be determined. In our work, two new polysaccharides were purified from PTX and named PTXP-1 and PTXP-2. Structural analysis showed that PTXP-1 is a glucan with a molecular weight of 915 Da and a structure of 4)-α-D-Glcp-(1 → as the main chain. PTXP-2 is a glucose arabinoglycan with 4)-α-D-Glcp-(1 → as the main chain, containing 8 glycosidic bonds attached, and a molecular weight of 57.9KDa. In vitro probiotic experiments demonstrated that PTXP-1 could significantly promote probiotic growth and acid production. In vivo experiments demonstrated that both PTXP-1 and PTXP-2 exhibited significant effectiveness in promoting the growth of intestinal probiotics. These findings help expand the application of polysaccharide components extracted from tonic herbs as functional food ingredients.

In this study, the curdlan-polyphenol complexes were constructed by a pH-driven method. The interaction between curdlan and various hydrophobic polyphenols (curcumin, quercetin, and chlorogenic acid) was investigated. Curdlan could self-assemble into particles for loading polyphenols through hydrogen bonding and hydrophobic interactions. The three polyphenols were embedded in curdlan in an amorphous state. The curdlan-curcumin complex showed the lowest viscoelasticity but exhibited the highest curcumin loading ability (34.04 ± 1.73 mg/g). However, the curdlan-chlorogenic acid complex emerged the opposite trend, indicating that the loading capacity was associated with the hydrophobicity of polyphenols. The antioxidant activity of curdlan significantly increased after combining with polyphenols, which could be maintained during in vitro simulated gastrointestinal digestion. In particular, the curdlan-quercetin complex exhibited the highest antioxidant activity and short-chain fatty acid concentration, which could influence gut microbiota composition by promoting the proliferation of Prevotella and inhibiting the growth of Escherichia_Shigella. In conclusion, the curdlan-polyphenol complexes prepared by an alcohol-free pH-driven method could effectively enhance the gastrointestinal stability of polyphenols as well as increase the antioxidant and prebiotic activities of curdlan, which could be applied as a functional ingredient to improve gut health.

Fucoidan from Laminaria japonica became sterilized with an autoclave and ultraviolet (UV) radiation. Potential prebiotic and antibacterial activities of sterilized fucoidans (SF) were the subject of investigation. Molecular weight, monosaccharide composition, FTIR, and NMR spectra of SF underwent evaluations to elucidate the relationship between the structure and activities of SF. The growth of Lactobacillus rhamnosus GG and L. acidophilus with autoclave sterilized fucoidan (ASF) and the growth of L. plantarum, L. gasseri, L. paracasei, and L. reuteri with UV sterilized fucoidan (USF) increased significantly. Also, fucoidan was vastly more effective than fructooligosaccharides in improving the growth of L. gasseri, L. reuteri, and L. paracasei. The growth of Escherichia coli and Bacillus cereus decreased at each SF concentration. ASF was more effective against E. coli, B. cereus, and Staphylococcus aureus than the USF efficiency. However, USF exhibited more inhibitory effects on the growth of Enterobacteriaceae compared to the ASF efficiency. When comparing the ASF and USF, autoclave caused a considerable decrease in molecular weight and uronic acid content, increased fucose and galactose, and made no significant changes in NMR spectra. Fucoidan effectively promoted probiotic bacterial growth and reduced pathogenic outbreaks in the medium. Therefore, it can occur as a new algal prebiotic and antibacterial agent.

Pectic polysaccharide is a bioactive ingredient in Chrysanthemum morifolium Ramat. \'Hangbaiju\' (CMH), but the high proportion of HG domain limited its use as a prebiotic. In this study, hot water, cellulase-assisted, medium-temperature alkali, and deep eutectic solvent extraction strategies were firstly used to extract pectin from CMH (CMHP). CMHP obtained by cellulase-assisted extraction had high purity and strong ability to promote the proliferation of Bacteroides and mixed probiotics. However, 4 extraction strategies led to general high proportion of HG domain in CMHPs. To further enhance the dissolution and prebiotic potential of CMHP, pectinase was used alone and combined with cellulase. The key factor for the optimal extraction was enzymolysis by cellulase and pectinase in a mass ratio of 3:1 at 1 % (w/w) dosage. The optimal CMHP had high yield (15.15 %), high content of total sugar, and Bacteroides proliferative activity superior to inulin, which was probably due to the cooperation of complex enzyme on the destruction of cell wall and pectin structural modification for raised RG-I domain (80.30 %) with relatively high degree of branching and moderate HG domain. This study provided a green strategy for extraction of RG-I enriched prebiotic pectin from plants.

Banana peel (BP) is the primary by-product generated during banana processing which causes numerous environmental issues. This study examines the physical attributes, proximate analysis, glycoarray profiling, antioxidant abilities, and prebiotic activity of BP. The analysis demonstrated that carbohydrates constituted the primary components of BP and the glycoarray profiling indicated that BP contains multiple pectin and hemicellulose structures. BP also contained phenolic compounds, including (+)-catechin and gallic acid, flavonoid compounds, and antioxidant activities. BP demonstrated prebiotic effects by promoting the proliferation of advantageous gut bacteria while inhibiting the growth of harmful bacteria. The prebiotic index scores demonstrated that BP exhibited a greater capacity to promote the growth of beneficial bacteria in comparison to regular sugar. The study demonstrated the potential of the BP as a valuable source of dietary fibre, bioactive compounds, and prebiotics. These components have beneficial characteristics and can be utilised in the production of food, feed additives, and functional food.

In this study, litchi polysaccharides were obtained from unfermented or fermented pulp by Lactobacillus fermentum (denoted as LP and LPF, respectively). The differences between LP and LPF in the colonic fermentation characteristics and modulatory of gut microbiota growth and metabolism were investigated with an in vitro fecal fermentation model. Results revealed that the strategies of gut bacteria metabolizing LP and LPF were different and LPF with lower molecular weight (Mw) was readily utilized by bacteria. The monosaccharide utilization sequence of each polysaccharide was Ara > Gla > GalA > GlcA ≈ Glu ≈ Man. Moreover, LPF promoted stronger proliferation of Bifidobacterium, Megamonas, Prevotella, and Bacteroides and higher SCFAs production (especially acetic and butyric acids) than LP. Correlation analysis further revealed that Mw could represent an essential structural feature of polysaccharides associated with its microbiota-regulating effect. Overall, Lactobacillus fermentation pre-treatment of litchi pulp promoted the fermentation characteristics and prebiotic activities of its polysaccharide.

Huangshui polysaccharides (HSPs) have attracted extensive attention recently for their biological activity and physicochemical property. This research investigated the extraction, structural characterization, and prebiotic activity of three different HSPs (HSP40-0, HSP60-0, and HSP80-0) in vitro to reveal the scientific support for the high-value utilization of Huangshui. HSPs were heteropolysaccharide with diverse structures and surface morphologies. Comprehensive analysis was conducted through 16S rRNA gene sequencing and metabolite profiling techniques, and results showed that HSPs had different potentials to regulate the gut microbiota due to their different structures; for instance, both HSP40-0 and HSP80-0 could notably increase the relative abundance of Bacteroidota, whereas HSP60-0 could increase the relative abundance of Phascolarctobacterium. In addition, HSPs upregulated beneficial differential metabolites, especially short-chain fatty acids (SCFAs). Fermentation products containing these metabolites exhibited anti-inflammatory effects on LPS-treated Caco-2 cells. This study will provide reference for exploring the relationship between the natural polysaccharide structure and the prebiotic activity and widen the application of Huangshui.