Glucans from fruit bodies of cultivated mushrooms Pleurotus ostreatus and Pleurotus eryngii: Structure and potential prebiotic activity

Effects of Rich in Β-Glucans Edible Mushrooms on Aging Gut Microbiota Characteristics: An In Vitro Study

Alterations of gut microbiota are evident during the aging process. Prebiotics may restore the gut microbial balance, with β-glucans emerging as prebiotic candidates. This study aimed to investigate the impact of edible mushrooms rich in β-glucans on the gut microbiota composition and metabolites by using in vitro static batch culture fermentations and fecal inocula from elderly donors (n = 8). Pleurotus ostreatus, P. eryngii, Hericium erinaceus and Cyclocybe cylindracea mushrooms derived from various substrates were examined. Gut microbiota composition (quantitative PCR (qPCR)) and short-chain fatty acids (SCFAs; gas chromatography (GC)) were determined during the 24-h fermentation. P. eryngii induced a strong lactogenic effect, while P. ostreatus and C. cylindracea induced a significant bifidogenic effect (p for all <0.05). Furthermore, P. eryngii produced on wheat straw and the prebiotic inulin had comparable Prebiotic Indexes, while P. eryngii produced on wheat straw/grape marc significantly increased the levels of tested butyrate producers. P. ostreatus, P. eryngii and C. cylindracea had similar trends in SCFA profile; H. erinaceus mushrooms were more diverse, especially in the production of propionate, butyrate and branched SCFAs. In conclusion, mushrooms rich in β-glucans may exert beneficial in vitro effects in gut microbiota and/or SCFAs production in elderly subjects.

Pleurotus Mushrooms Content in Glucans and Ergosterol Assessed by ATR-FTIR Spectroscopy and Multivariate Analysis

Attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectroscopy was used to monitor the infrared absorption spectra of 79 mushroom samples from 29 Pleurotus ostreatus, P. eryngii and P. nebrodensis strains cultivated on wheat straw, grape marc and/or by-products of the olive industry. The spectroscopic analysis provided a chemical insight into the mushrooms examined, while qualitative and quantitative differences in regions related to proteins, phenolic compounds and polysaccharides were revealed among the species and substrates studied. Moreover, by using advanced chemometrics, correlations of the recorded mushrooms’ spectra versus their content in glucans and ergosterol, commonly determined through traditional analytical techniques, allowed the development of models predicting such contents with a good predictive power (R²: 0.80–0.84) and accuracy (low root mean square error, low relative error and representative to the predicted compounds spectral regions used for the calibrations). Findings indicate that FTIR spectroscopy could be exploited as a potential process analytical technology tool in the mushroom industry to characterize mushrooms and to assess their content in bioactive compounds.

Structure-Functional Activity Relationship of β-Glucans From the Perspective of Immunomodulation: A Mini-Review

β-Glucans are a heterogeneous group of glucose polymers with a common structure comprising a main chain of β-(1,3) and/or β-(1,4)-glucopyranosyl units, along with side chains with various branches and lengths. β-Glucans initiate immune responses via immune cells, which become activated by the binding of the polymer to specific receptors. However, β-glucans from different sources also differ in their structure, conformation, physical properties, binding affinity to receptors, and thus biological functions. The mechanisms behind this are not fully understood. This mini-review provides a comprehensive and up-to-date commentary on the relationship between β-glucans' structure and function in relation to their use for immunomodulation.

Agaricus bisporus By-Products as a Source of Chitin-Glucan Complex Enriched Dietary Fibre with Potential Bioactivity

Mushroom production generates large amounts of by-products whose disposal creates environmental problems. The high abundance of biological active non-starch polysaccharides in mushroom cell walls makes these by-products attractive for dietary fiber-based ingredient (DFI) production. Traditional methods of dietary fiber preparation didn’t allow to obtain a DFI with suitable chemical and functional properties. In this work a simple and environmentally friendly method was developed and optimized for DFI production using a central composite design with treatment time, hydrogen peroxide and sodium hydroxide concentration as factors and chemical composition, chromatic and functional properties as dependent variables. The chemical composition of the DFI was strongly influenced by the process parameters and its functional and color properties were dependent on its fiber and protein content, respectively. The method developed is simple, uses food grade and low-cost reagents and procedures yielding a DFI with white color, no odor and a high concentration of dietary fiber (>60%) with an identical sugar composition to the original mushroom fiber. Due to the high water and oil retention capacity, this DFI may be used not only for dietary fiber enrichment and reduction of the food energy value but also as a functional ingredient with potential bioactivity.

Use of a Pleurotus ostreatus Complex Cell Wall Extract as Elicitor of Plant Defenses: From Greenhouse to Field Trial

Fungi constitute an abundant source of natural polysaccharides, some of them harboring original structures which can induce responses in mammalian or plant cells. An alkaline extract from the edible mushroom Pleurotus ostreatus has been obtained and called Pleuran complex cell wall extract (CCWE). It consists of a glucan-peptide complex whose components fall in a quite broad range of molecular weights, from 30 to 80 kDa. Pleuran extract has been tested on cultivated plants in laboratory conditions and also during field trial for its capacity to stimulate plant defenses in response to pathogen attack. Following Pleuran CCWE treatment, enhanced levels of various biochemical markers associated with plant responses have been observed, including enzymatic activities (e.g., peroxidase) or expression of some pathogenesis-related genes. In addition, during field experiments, we have noticed significant reductions in disease symptom levels in relation to different plant/pathogen systems (wheat/septoria, vine/mildew). These results confirmed that Pleuran CCWE could be used as an elicitor of plant defenses and could help in reducing pesticide applications against plant pathogens.

Study of prebiotic properties of selected banana species in Thailand

Prebiotics are functional foods with health-promoting properties that are used in many developed countries. Thailand is one of the countries that produces many plants that should have prebiotic properties. In this study, we investigated the potential prebiotic effects of powders obtained from Saba, Pisang Awak Banana and Silver bluggoe in vitro in accordance with their physical, chemical and microbiological properties. These selected plants were found to demonstrate good water-/oil-binding properties. They contained chlorophyll, beta carotene and lycopene and showed good resistance to stomach and small-intestine enzymes. The selected plants were further used to evaluate prebiotic properties by supplementing as a carbon source in culturing broth for growing probiotic bacteria and pathogenetic bacteria. The increase in the number of probiotic bacteria during fermentation of these selected plants correlated with decreased pH. The growth of four strains of probiotic bacteria seemed to be promoted in MRS broth containing these selected plants, but no significant differences in the number of probiotic bacterial groups were detected in response to difference concentrations of all these selected plants. In addition, we noted that a decrease in the number of all four strains of pathogenic bacteria during fermentation of these selected plants correlated with a decreased pH. Moreover, the antimicrobial activity of selected plant prebiotics supported probiotic substance production to inhibit growth of pathogenic bacteria. In conclusion, we have shown that the addition of selected prebiotic plants, indicating that they should be used as a prebiotic food ingredient, represents a potential alternative to available commercial prebiotics.

Enhancing Activity of Pleurotus sajor-caju (Fr.) Sing β-1,3-Glucanoligosaccharide (Ps-GOS) on Proliferation, Differentiation, and Mineralization of MC3T3-E1 Cells through the Involvement of BMP-2/Runx2/MAPK/Wnt/β-Catenin Signaling Pathway

Osteoporosis is a leading world health problem that results from an imbalance between bone formation and bone resorption. β-glucans has been extensively reported to exhibit a wide range of biological activities, including antiosteoporosis both in vitro and in vivo. However, the molecular mechanisms responsible for β-glucan-mediated bone formation in osteoblasts have not yet been investigated. The oyster mushroom Pleurotus sajor-caju produces abundant amounts of an insoluble β-glucan, which is rendered soluble by enzymatic degradation using Hevea glucanase to generate low-molecular-weight glucanoligosaccharide (Ps-GOS). This study aimed to investigate the osteogenic enhancing activity and underlining molecular mechanism of Ps-GOS on osteoblastogenesis of pre-osteoblastic MC3T3-E1 cells. In this study, it was demonstrated for the first time that low concentrations of Ps-GOS could promote cell proliferation and division after 48 h of treatment. In addition, Ps-GOS upregulated the mRNA and protein expression level of bone morphogenetic protein-2 (BMP-2) and runt-related transcription factor-2 (Runx2), which are both involved in BMP signaling pathway, accompanied by increased alkaline phosphatase (ALP) activity and mineralization. Ps-GOS also upregulated the expression of osteogenesis related genes including ALP, collagen type 1 (COL1), and osteocalcin (OCN). Moreover, our novel findings suggest that Ps-GOS may exert its effects through the mitogen-activated protein kinase (MAPK) and wingless-type MMTV integration site (Wnt)/β-catenin signaling pathways.

Nanomaterials Derived from Fungal Sources-Is It the New Hype?

Greener alternatives to synthetic polymers are constantly being investigated and sought after. Chitin is a natural polysaccharide that gives structural support to crustacean shells, insect exoskeletons, and fungal cell walls. Like cellulose, chitin resides in nanosized structural elements that can be isolated as nanofibers and nanocrystals by various top-down approaches, targeted at disintegrating the native construct. Chitin has, however, been largely overshadowed by cellulose when discussing the materials aspects of the nanosized components. This Perspective presents a thorough overview of chitin-related materials research with an analytical focus on nanocomposites and nanopapers. The red line running through the text emphasizes the use of fungal chitin that represents several advantages over the more popular crustacean sources, particularly in terms of nanofiber isolation from the native matrix. In addition, many β-glucans are preserved in chitin upon its isolation from the fungal matrix, enabling new horizons for various engineering solutions.

Processed Fruiting Bodies of Lentinus edodes as a Source of Biologically Active Polysaccharides

Water soluble polysaccharides (WSP) were isolated from Lentinus edodes fruiting bodies. The mushrooms were previously subjected to various processing techniques which included blanching, boiling, and fermenting with lactic acid bacteria. Therefore, the impact of processing on the content and biological activities of WSP was established. Non-processed fruiting bodies contained 10.70 ± 0.09 mg/g fw. Boiling caused ~12% decrease in the amount of WSP, while blanched and fermented mushrooms showed ~6% decline. Fourier transform infrared spectroscopy analysis (FTIR) confirmed the presence of β-glycosidic links, whereas due to size exclusion chromatography 216 kDa and 11 kDa molecules were detected. WSP exhibited antioxidant potential in FRAP (ferric ion reducing antioxidant power) and ABTS (2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid)) assays. Cytotoxic properties were determined on MCF-7 and T47D human breast cell lines using MTT (3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide) test. Both biological activities decreased as the result of boiling and fermenting.

In vitro prebiotic activities of oligosaccharides from the by-products in Ganoderma lucidum spore polysaccharide extraction

Until recently, a variety of oligosaccharides from fruits, vegetables and mushrooms have demonstrated positive prebiotic effects. Ganoderma lucidum, a well-known traditional medicine and tonic in East Asia, has been utilized in the prevention and treatment of a broad range of illnesses. In this study, each of three oligosaccharides was obtained from the polysaccharide extraction by-products of sporoderm: the unbroken and broken spores of Ganoderma lucidum (UB-GLS, B-GLS). Their molecular weight distribution, monosaccharide composition and preliminary structures were analyzed using gel permeation chromatography (GPC), GC-MS, UV and FTIR, respectively. All of the oligosaccharides were found to exhibit prebiotic activities, evaluated by detecting growth stimulation on Lactobacillus in vitro. Among these, UB-O80 and B-O80 displayed the most significant effects (p < 0.05) in these groups, and UB-O80 showed higher resistance to hydrolysis by artificial human gastric juice compared with inulin, giving a maximum hydrolysis rate of 1.65%. Compared with inulin media, Lactobacillus also revealed high tolerance to lower pH levels and simulated gastric juices in UB-O80 and B-O80 media. Compared with a control in gut microbiota fermentation, the abundance of some beneficial bacteria increased and some harmful bacteria declined in the groups of UB-O80 and B-O80. In conclusion, the results suggest that GLS oligosaccharides could be exploited as promising prebiotics for the enhancement of human health.

Until recently, a variety of oligosaccharides from fruits, vegetables and mushrooms have demonstrated positive prebiotic effects.

Polysaccharides of mushroom Pleurotus spp.: New extraction techniques, biological activities and development of new technologies

The biodiversity of mushrooms Pleurotus spp. is impressive due to its complexity and diversity related to the composition of chemical structures such as polysaccharides, glycoproteins and secondary metabolites such as alkaloids, flavonoids and betalains. Recent studies of polysaccharides and their structural elucidation have helped to direct research and development of technologies related to pharmacological action, production of bioactive foods and application of new, more sophisticated extraction tools. The diversity of bioactivities related to these biopolymers, their mechanisms and routes of action are constant focus of researches. The elucidation of bioactivities has helped to formulate new vaccines and targeted drugs. In this context, in terms of polysaccharides and the diversity of mushrooms Pleurotus spp., this review seeks to revisit the genus, making an updated approach on the recent discoveries of polysaccharides, new extraction techniques and bioactivities, emphasising on their mechanisms and routes in order to update the reader on the recent technologies related to these polymers.

A Report on Fungal (1→3)-α-d-glucans: Properties, Functions and Application

The cell walls of fungi are composed of glycoproteins, chitin, and α- and β-glucans. Although there are many reports on β-glucans, α-glucan polysaccharides are not yet fully understood. This review characterizes the physicochemical properties and functions of (1→3)-α-d-glucans. Particular attention has been paid to practical application and the effect of glucans in various respects, taking into account unfavourable effects and potential use. The role of α-glucans in plant infection has been proven, and collected facts have confirmed the characteristics of Aspergillus fumigatus infection associated with the presence of glucan in fungal cell wall. Like β-glucans, there are now evidence that α-glucans can also stimulate the immune system. Moreover, α-d-glucans have the ability to induce mutanases and can thus decompose plaque.

Selenium-enriched Coriolus versicolor mushroom biomass: potential novel food supplement with improved selenium bioavailability

BACKGROUND

The ability of Coriolus versicolor medicinal mushroom to accumulate and transform selenium from selenourea and sodium selenite into an organic form - l-selenomethionine - during growth in liquid medium is examined in this paper. Additionally, the impact of supplementation on biological activity of the selenated mushroom methanol extracts, as well as their chemical composition, is studied.

RESULTS

Selenium accumulation was more efficient with sodium selenite application, but biomass yield was significantly lower (1.89 g DW L^-1 ) compared to samples enriched with selenourea (4.48 g DW L^-1 ). Mushroom sample obtained after growing in liquid medium with selenourea had significantly higher l-selenomethionine content compared to the sample grown in medium with sodium selenite. Selenium-enriched methanol extracts of C. versicolor mushroom showed improved antimicrobial and antioxidant activities compared to non-enriched extract.

CONCLUSION

Our results suggest that C. versicolor mushroom cultivated in liquid culture enriched with selenourea can be used for the production of novel food supplements with improved selenium bioavailability. More than 30% of total accumulated selenium from selenourea is transformed into l-selenomethionine. Differences in biological activity of methanol extracts can be explained not only by different selenium content but also by the differences in chemical composition of extracts. © 2019 Society of Chemical Industry.

Polysaccharides from Basidiocarps of Cultivating Mushroom Pleurotus ostreatus: Isolation and Structural Characterization

Oyster mushrooms are an interesting source of biologically active glucans and other polysaccharides. This work is devoted to the isolation and structural characterization of polysaccharides from basidiocarps of the cultivated oyster mushroom, Pleurotus ostreatus. Five polysaccharidic fractions were obtained by subsequent extraction with cold water, hot water and two subsequent extractions with 1 m sodium hydroxide. Branched partially methoxylated mannogalactan and slightly branched (1→6)-β-d-glucan predominated in cold- and hot-water-soluble fractions, respectively. Alternatively, these polysaccharides were obtained by only hot water extraction and subsequent two-stage chromatographic separation. The alkali-soluble parts originating from the first alkali extraction were then fractionated by dissolution in dimethyl sulfoxide (DMSO). The polysaccharide insoluble in DMSO was identified as linear (1→3)-α-d-glucan, while branched (1→3)(1→6)-β-d-glucans were found to be soluble in DMSO. The second alkaline extract contained the mentioned branched β-d-glucan together with some proteins. Finally, the alkali insoluble part was a cell wall complex of chitin and β-d-glucans.

Structure, bioactivity and applications of natural hyperbranched polysaccharides

In recent years, hyperbranched polymers, especially the natural hyperbranched polysaccharides (HBPSs), are receiving much attention due to their diverse biological activities and applications. With high degree of branching (DB), HBPSs mainly exist in the form of either a comb-brush shape, dendrimer-like particulate, or globular particle. HBPSs also possess some unique properties, such as high density, large spatial cavities, and numerous terminal functional groups, which distinguish them from other polymers. As a natural biopolymer, HBPS has excellent bioavailability, biocompatibility, and biodegradability, which have versatile applications in the fields of food, medicine, cosmetic, and nanomaterials. In this review, the source and structure of HBPSs from plant, animal, microbial and fungal origins as well as their biological functions and applications are covered, with the aim of further advancing the research of their structure and bioactivity.

Structural studies of a water insoluble β-glucan from Pleurotus djamor and its cytotoxic effect against PA1, ovarian carcinoma cells

A water insoluble β-glucan (PS), with molecular mass ∼9.16 × 10⁴ Da was isolated from the 4% alkaline extract of an edible mushroom, Pleurotus djamor and found to consist of (1→3)-β-d-glucopyranosyl moiety. The structure of the PS was elucidated on the basis of total hydrolysis, methylation analysis, periodate oxidation, and NMR experiments (¹H, ¹³C, DQF-COSY, DEPT-135, and HSQC). The structure of the repeating unit of the polysaccharide was established as: →3)-β-d-Glcp-(1→. The water insoluble β-glucan showed cytotoxic effect against PA1 cells, where˜50% population was destroyed at 100 μg/mL concentration, and almost all cells at 250 μg/mL concentration. The wound healing assay showed significant anticarcinogenic effect against ovarian carcinoma PA1 cells after 48 h of treatment.

Valorization of Olive By-Products as Substrates for the Cultivation of Ganoderma lucidum and Pleurotus ostreatus Mushrooms with Enhanced Functional and Prebiotic Properties

The successful management of olive by-products constitutes a major challenge due to their huge volume, high organic content, and toxicity. Olive-mill wastes (TPOMW) and olive pruning residues (OLPR) were evaluated as substrates for the cultivation of Ganoderma lucidum and Pleurotus ostreatus. Chemical composition, glucans, total phenolic content, and antioxidant activity were measured in mushrooms, and their prebiotic potential was assessed by examining their effect on the growth of four intestinal bacteria. Several substrates based on olive by-products had a positive impact on P. ostreatus mushroom production, whereas only one performed adequately for G. lucidum. Increased ratios of OLPR to wheat-straw resulted in an increase of crude protein content in P. ostreatus fruit-bodies by up to 42%, while G. lucidum mushrooms from OLPR-based substrates exhibited an up to three-fold increase in α-glucan, or a significant enhancement of β-glucan content, when compared to beech sawdust (control). The mushrooms’ FTIR spectra confirmed the qualitative/quantitative differentiation detected by standard assays. In regard to prebiotic properties, mushrooms powder supported or even enhanced growth of both Lactobacillus acidophilus and L. gasseri after 24/48 h of incubation. In contrast, a strain-specific pattern was observed in bifidobacteria; mushrooms hindered Bifidobacterium bifidum growth, whereas they supported a similar-to-glucose growth for B. longum.

Effects of pulverized oyster mushroom (Pleurotus ostreatus) on diarrhea incidence, growth performance, immunity, and microbial composition in piglets

BACKGROUND

Pleurotus ostreatus mushroom (POM) is an edible mushroom with rich nutritional components and vital pharmacological properties. The present study comprised 100 cross-bred piglets, weaned at 28 days old, who were randomly assigned to four POM diets with five replicates per diet and five piglets per pen.

RESULTS

POM supplementation (P < 0.05) decreased the incidence of diarrhea, and also increased the average daily feed intake and average daily gain of pigs. Fecal acetate, butyrate and propionate increased with the addition of POM. Interleukin-2, immunoglobulin G, immunoglobulin M, tumor necrosis factor-α and immunoglobulin A increased (P < 0.05) with the addition of POM. The 16S rDNA sequencing results showed that the Bacteroidetes and Firmicutes were the dominant microbial strains in the fecal samples, irrespective of POM supplementation. Shannon diversity, whole tree phylogenetic diversity, observed species and Chao1 analysis exhibited significant variation in species richness across the treatments. Principal coordinates analysis showed a significant (P < 0.1) increase in the microbial communities amongst all of the treatment groups.

CONCLUSION

The results of the present study suggest that the supplementation of POM in the diet of piglets might increase feed consumption, gut microbial composition and diversity, as well as short-chain fatty acids synthesis, consequently preventing the occurrence of diarrhea and increasing the growth of piglets. © 2019 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Lactic Acid Fermentation of Edible Mushrooms: Tradition, Technology, Current State of Research: A Review

Pickling is one of the methods for preserving food. However, this term may refer to both types of products, that is, to those subjected to lactic acid fermentation and to marinated ones (acidified) that are usually produced by the addition of acetic acid. Various raw materials are subjected to lactic acid fermentation (vegetable and animal origin), which yields food products with high nutritional and dietary value. In many regions of the world, the process of lactic fermentation is also traditionally used to preserve fruiting bodies of edible mushrooms. Mushrooms are appreciated for their organoleptic qualities as well as the presence of many different bioactive substances exhibiting healing and health-promoting properties. This article reviews the literature related to the use of lactic fermentation in the process of mushroom preservation. Particular attention has been paid to the aspects of the technological process and its impact on the quality and suitability of the final products. Moreover, research results concerning the influence of lactic fermentation on chemical and physical changes in fruiting bodies of edible fungi are also presented.

Use of sodium alginate in the preparation of gelatin-based hard capsule shells and their evaluation in vitro

Using only type B gelatin produces hard capsule shells which are too brittle. This study examines the blending of type B bovine gelatin with sodium alginate to produce hard capsule shells and through evaluation of their in vitro physicochemical properties provides a reflection on the role of gelatin and sodium alginate in the blend. The compositions and formulation of the capsule shells in this study comprised gelatin (10%, 20% and 30%), sodium alginate (1%, 2%, 3%, 4% and 5%), water, and opacifying agents (titanium dioxide; TiO₂) and polyethylene glycol (PEG) whose concentrations were kept constant. From the 15 films prepared, five were found to form hard capsule shells. Increased concentrations of sodium alginate increased the viscosity of the blends accompanied by capsule thickening. There was a good molecular compatibility between gelatin and sodium alginate. Increased gelatin and sodium alginate concentrations increased the water-holding capacity of the film, which decreased the redness (a*), lightness (L*), blueness (b*), variation in the color parameters (ΔE*) and the whiteness index (WI). The weight of the capsule shells ranged between 0.080 g and 0.25 g and the moisture content was between 5% and 11%. Ash contents for all the formulations were below 5% and the sensitivity of capsules at pH 7 was higher than that at acidic pH. Highest rupture times were observed with simulated gastric fluid (SGF, pH 1) for all formulations. Increased gelatin concentration decreased the resistance of the capsule to force while increased sodium alginate concentration had no effect on resistance to force.

Using only type B gelatin produces hard capsule shells which are too brittle.

A 3-O-methylated heterogalactan from Pleurotus eryngii activates macrophages

Mushroom-derived polysaccharides exhibit various biological activities owing to their diverse structural features. Here, we purified a 3-O-methylated heterogalactan (WPEP-N-b, Mw 21.4 kDa) from the fruiting bodies of Pleurotus eryngii. WPEP-N-b is composed primarily of galactose (43.8%), mannose (39.3%), methyl-galactose (11.7%) and glucose (9.2%) residues, with the main chain being composed of α-1,6-linked D-Galp and 3-O-Me-D-Galp, branched at O-2 with single t-β-D-Manp as major the side chain. β-1,6-D-Glcp residues are present as minor components either in side-chains or backbone. WPEP-N-b increases macrophage phagocytosis and secretion of NO, TNF-α, IL-6 and IL-1β. Mechanistic studies demonstrate that WPEP-N-b promotes the degradation of IκB-α, and enhances phosphorylation of MAPKs and the NF-κB p65 subunit. Our results also indicate that this polysaccharide activates RAW264.7 cells via MAPK and NF-κB signaling pathways and the Toll-like receptor 2(TLR2). These results increase our understanding as to how mushroom-derived polysaccharides modulate the immunologic process.

In vitro Prebiotic Effects of Bamboo Shoots and Potato Peel Extracts on the Proliferation of Lactic Acid Bacteria Under Simulated GIT Conditions

The present study explored the possible prebiotic application of potato peel and bamboo shoot extracts for the proliferation of lactic acid bacteria (LAB) from diverse niches and their tolerance ability to simulated gastrointestinal tract (GIT) conditions was also examined. Initially, the complete 16S rDNA sequencing of selected isolates revealed them as Lactobacillus paracasei (6), Staphylococcus simulans (2), and Streptococcus thermophilus (1). Higher cell densities and rapid pH change were obtained from cultured media supplemented with BS (2%) and PP (2%) as a carbon source. Their higher tolerance and the lowest reducing sugar abilities were obtained for BS at pH 2.5 and 9.0, while at pH 3.5 and 8.0 for PP. The isolates were screened for additional functional and technological properties to harvest the most appropriate starter. The selected isolates harbored promising functional properties such as amylase presence, cell surface hydrophobicity, autoaggregation, proteolytic and lipolytic activity, antifungal action, as well as exopolysaccharide production. On the basis of these attributes, microencapsulated strain K3 was found resistant to gastrointestinal conditions after 2 h, resulting in significantly (p ≤ 0.05) improved survival compared to non-capsulated strain. The current approach presents an interesting economical strategy to modulate LAB through supplementation of plant-derived carbon sources as well as to enhance their survival under GIT.