Preparation and prebiotic potential of pectin oligosaccharides obtained from citrus peel pectin

Structural and rheological properties of diluted alkali soluble pectin from apple and carrot

Pectin, a complex polysaccharide found in plant cell walls, plays a crucial role in various industries due to its functional properties. The diluted alkali-soluble pectin (DASP) fractions that result from the stepwise extraction of apples and carrots were studied to evaluate their structural and rheological properties. Homogalacturonan and rhamnogalacturonan I, in different proportions, were the main pectin domains that composed DASP from both materials. Atomic force microscopy revealed that the molecules of apple DASP were longer and more branched. A persistence length greater than 40 nm indicated that the pectin molecules deposited on mica behaved as stiff molecules. The weight-averaged molar mass was similar for both samples. Intrinsic viscosity values of 194.91 mL·g-1 and 186.79 mL·g-1 were obtained for apple and carrot DASP, respectively. Rheological measurements showed greater structural strength for apple-extracted pectin, whereas carrot pectin was characterized by a higher linear viscoelasticity limit. This comparison showed that the pectin fractions extracted by diluted alkali are structurally different and have different rheological properties depending on their botanical origin. The acquired insights can enhance the customized use of pectin residue and support further investigations in industries relying on pectin applications.

Comparative analysis of pectin and prebiotics on human microbiota modulation in early life stages and adults

The gut microbiota is essential in human health, influencing various physiological processes ranging from digestion and metabolism to immune function and mental health. Dietary fiber pectins and prebiotics have emerged as key modulators of gut microbiota composition and function, offering potential therapeutic implications for promoting gut health and preventing intestinal inflammatory diseases. In this review, we explore the modulation of gut microbiota by dietary fiber pectins and prebiotics in infants and adults. We begin with an overview of the gut microbiota composition and function in different age groups, highlighting the factors in shaping microbial communities in both age groups, especially the effect of diet. We then delve into the impact of dietary fiber pectins and prebiotics on gut microbiota composition and function, examining their effects on digestive health, intestinal barrier integrity, immune function, metabolic health, and mental health across different life stages. We further compare how aging affects the gut function and immune system, and we discuss the main health outcomes associated with dietary fiber intake and prebiotics, including the impact on digestive health, improvement in immune function, improvement in cholesterol and glucose metabolism, weight management, mental health, and prevention of diseases. Finally, we highlight the challenges and future directions for research. By advancing the understanding of gut microbiota dynamics and translating scientific insights into clinical practice, it could harness the full potential of dietary fiber pectins and prebiotics to optimize gut health, improve overall well-being across the lifespan, and increase longevity.

Bigel Matrix Loaded with Probiotic Bacteria and Prebiotic Dietary Fibers from Berry Pomace Suitable for the Development of Probiotic Butter Spread Product

This study presents a novel approach to developing a probiotic butter spread product. We evaluated the prebiotic activity of soluble dietary fibers extracted from cranberry and sea buckthorn berry pomace with different probiotic strains (Limosilactobacillus reuteri, Lacticaseibacillus paracasei, and Lactiplantibacillus plantarum), uploaded selected compatible combination in the bigel matrix, and applied it in the probiotic butter spread formulation. Bigels and products were characterized by physical stability, rheological, textural properties, and viability of probiotics during storage at different conditions. The highest prebiotic activity score was observed in soluble cranberry (1.214 ± 0.029) and sea buckthorn (1.035 ± 0.009) fibers when cultivated with L. reuteri. The bigels loaded with probiotics and prebiotic fiber exhibited a significant increase in viscosity (higher consistency coefficient 40-45 Pa·sn) and better probiotic viability (>6 log CFU/g) during long-term storage at +4 °C temperature, surpassing the bigels loaded with probiotics alone. Bigels stored at a lower temperature (-18 °C) maintained high bacterial viability (above 8.5 log CFU/g). The butter spread enriched with the bigel matrix was softer (7.6-14.2 N), indicating improved spreadability. The butter spread product consistently met the required 6 log CFU/g for a functional probiotic food product until 60 days of storage at +4 °C temperature. The butter stored at -18 °C remained probiotic throughout the entire storage period, confirming the protective effect of the bigel matrix. The study's results showed the potential of the bigel to co-encapsulate, protect, and deliver probiotics during prolonged storage under different conditions.

Biochemical characterization of a novel acid-active endopolygalacturonase for pectin depolymerization, pectic-oligomer production, and fruit juice clarification

Endopolygalacturonases are crucial pectinases known for their efficient and sustainable pectin depolymerization activities. The present study identified a novel gene encoding endopolygalacturonase from an acidic mine tailing metagenome. The putative gene showed a maximum identity of 67.55 % with an uncharacterized peptide sequence from Flavobacterium fluvii. The gene was cloned and expressed in a heterologous host, E. coli. Biochemical characterization of the novel endopolygalacturonase enzyme variant (EPHM) showed maximum activity at 60 °C and at 5.0 pH, while retaining 50 % activity under the temperature and pH range of 20 °C to 70 °C for 6 h, and 3.0 to 10.0 for 3 h, respectively. The enzyme exhibited tolerance to different metal ions. EPHM was characterized for the depolymerization of methylated pectin into pectic oligosaccharides. Further, its utility was established for fruit juice clarification, as endorsed by high transmittance, significant viscosity reduction, and release of reducing sugars in the treated fruit juice samples.

Degradation Mechanisms of Six Typical Glucosidic Bonds of Disaccharides Induced by Free Radicals

Increasing hydrogen peroxide (H2O2)-based systems have been developed to degrade various polysaccharides due to the presence of highly reactive free radicals, but published degradation mechanisms are still limited. Therefore, this study aimed to clarify the degradation mechanism of six typical glucosidic bonds from different disaccharides in an ultraviolet (UV)/H2O2 system. The results showed that the H2O2 concentration, disaccharide concentration, and radiation intensity were important factors affecting pseudo-first-order kinetic constants. Hydroxyl radical, superoxide radical, and UV alone contributed 58.37, 18.52, and 19.17% to degradation, respectively. The apparent degradation rates ranked in the order of cellobiose ≈ lactose > trehalose ≈ isomaltose > turanose > sucrose ≈ maltose. The reaction pathways were then deduced after identifying their degradation products. According to quantum chemical calculations, the cleavage of α-glycosidic bonds was more kinetically unfavorable than that of β-glycosidic bonds. Additionally, the order of apparent degradation rates depended on the energy barriers for the formation of disaccharide-based alkoxyl radicals. Moreover, energy barriers for homolytic scissions of glucosidic C1-O or C7-O sites of these alkoxyl radicals ranked in the sequence: α-(1 → 2) ≈ α-(1 → 3) < α-(1 → 4) < β-(1 → 4) < α-(1 → 6) < α-(1 → 1) glucosidic bonds. This study helps to explain the mechanisms of carbohydrate degradation by free radicals.

An overview of microbial enzymatic approaches for pectin degradation

Pectin, a complex natural macromolecule present in primary cell walls, exhibits high structural diversity. Pectin is composed of a main chain, which contains a high amount of partly methyl-esterified galacturonic acid (GalA), and numerous types of side chains that contain almost 17 different monosaccharides and over 20 different linkages. Due to this peculiar structure, pectin exhibits special physicochemical properties and a variety of bioactivities. For example, pectin exhibits strong bioactivity only in a low molecular weight range. Many different degrading enzymes, including hydrolases, lyases and esterases, are needed to depolymerize pectin due to its structural complexity. Pectin degradation involves polygalacturonases/rhamnogalacturonases and pectate/pectin lyases, which attack the linkages in the backbone via hydrolytic and β-elimination modes, respectively. Pectin methyl/acetyl esterases involved in the de-esterification of pectin also play crucial roles. Many α-L-rhamnohydrolases, unsaturated rhamnogalacturonyl hydrolases, arabinanases and galactanases also contribute to heterogeneous pectin degradation. Although numerous microbial pectin-degrading enzymes have been described, the mechanisms involved in the coordinated degradation of pectin through these enzymes remain unclear. In recent years, the degradation of pectin by Bacteroides has received increasing attention, as Bacteroides species contain a unique genetic structure, polysaccharide utilization loci (PULs). The specific PULs of pectin degradation in Bacteroides species are a new field to study pectin metabolism in gut microbiota. This paper reviews the scientific information available on pectin structural characteristics, pectin-degrading enzymes, and PULs for the specific degradation of pectin.

Preparation, structural characterization, bioactivities, and applications of Crataegus spp. polysaccharides: A review

Crataegus, is a genus within the Rosaceae family. It is recognized as a valuable plant with both medicinal and edible qualities, earning it the epithet of the "nutritious fruit" owing to its abundant bioactive compounds. Polysaccharides are carbohydrate polymers linked by glycosidic bonds, one of the crucial bioactive ingredients of Crataegus spp. Recently, Crataegus spp. polysaccharides (CPs) have garnered considerable attention due to their diverse range of bioactivities, including prebiotic, hypolipidemic, anticancer, antibacterial, antioxidant, and immunobiological properties. Herein, we provide a comprehensive overview of recent research on CPs. The analysis revealed that CPs exhibited a broad molecular weight distribution, ranging from 5.70 Da to 4.76 × 108 Da, and are composed of various monosaccharide constituents such as mannose, rhamnose, and arabinose. Structure-activity relationships demonstrated that the biological function of CPs is closely associated with their molecular weight, galacturonic acid content, and chemical modifications. Additionally, CPs have excellent bioavailability, biocompatibility, and biodegradability, which make them promising candidates for applications in the food, medicine, and cosmetic industries. The article also scrutinized the potential development and future research directions of CPs. Overall, this article provides comprehensive knowledge and underpinnings of CPs for future research and development as therapeutic agents and multifunctional food additives.

Structural and chemical insights into the prebiotic property of hemicellulosic polysaccharide from Santalum album L

Hemicellulose was extracted by alkali treatment of de-pectinated cell wall material of Santalum album L. (sandalwood) suspension culture cells. The physicochemical properties and prebiotic activities of a purified major fraction of Hemicellulose-B, termed as HB-I, were investigated. GC analysis of hydrolyzed and derivatized HB-I showed the presence of arabinose (~64 %), galactose (~16 %) and glucose (~16 %) as major monosaccharide units along with minor amount of rhamnose. Methylation and NMR studies on the purified polysaccharide revealed the presence of 6-β-d-Glcp, β-d-Galp, 3,5-α-l-Araf, α-l-Araf, 5-α-l-Araf, 2,3-α-l-Araf and, α-l-Rhap residues, from which a proposed structure of repeating units was established. The growth of probiotic Lactobacillus spp. strains L. acidophilus, L. casei, L. plantarum and L. rhamnosus was promoted while that of Escherichia coli was suppressed significantly in presence of HB-I. Our results highlight valorization of sandalwood biomass and explore the role of mixed α, β-linked heteroglycan as a potential prebiotic molecule thus indicating the possibility of development of low-cost bioprocesses for production of functional food ingredients.

Indigenous fungal strains isolation and molecular identification from coffee pulp for the production of pectic oligosaccharides

Coffee pulp (CP) is a significant agro-industrial waste generated during coffee bean processing, which possess substantial environmental contamination and is rich in pectin. The primary objective of this study was to investigate the conversion of pectin extracted from coffee pulp into pectic oligosaccharides (POS) using native microbial strains. The study aimed to optimize the growing conditions, including temperature, time, and pectin concentration, to assess the productivity of pectinase. Two fungal strains that exhibited the highest growth on CP were isolated and subsequently identified as Aspergillus fumigatus P-1007 and A. fumigatus HA1, employing 5.8S rRNA gene sequencing. The optimization of temperature for the organism was carried out between 25 and 45 °C; compared to the other temperatures at 45 °C the productivity of pectinase was high; the exact temperature was used for the time experiment where we found that compared to the A. fumigatus P-1007, A. fumigates HA1 was showed high enzyme productivity on 6th day. Hence, the highest productivity of endo-pectinase was seen at a temperature of 45 °C on the 6th day using isolated A. fumigates HA1 in the CP with 1% of coffee pectin. Additionally, the produced POS were screened and confirmed through TLC and HPLC analysis. The antioxidant activity of the POS derived from the separated CP demonstrated an effective concentration (EC50) of 400 µg/ml. The study indicates that the efficient utilization of CP waste for producing potentially valuable functional food ingredients, such as POS, holds promise for commercial development.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13205-023-03811-9.

Towards Valorization of Food-Waste-Derived Pectin: Recent Advances on Their Characterization and Application

Pectin, a natural biopolymer, can be extracted from food waste biomass, adding value to raw materials. Currently, commercial pectin is mostly extracted from citrus peels (85.5%) and apple pomace (14.0%), with a small segment from sugar beet pulp (0.5%). However, driven by high market demand (expected to reach 2.12 billion by 2030), alternative agro-industrial waste is gaining attention as potential pectin sources. This review summarizes the recent advances in characterizing pectin from both conventional and emerging food waste sources. The focus is the chemical properties that affect their applications, such as the degree of esterification, the neutral sugars' composition, the molecular weight, the galacturonic acid content, and technological-functional properties. The review also highlights recent updates in nutraceutical and food applications, considering the potential use of pectin as an encapsulating agent for intestinal targeting, a sustainable biopolymer for food packaging, and a functional and emulsifying agent in low-calorie products. It is clear from the considered literature that further studies are needed concerning the complexity of the pectin structure extracted from emerging food waste raw materials, in order to elucidate their most suitable commercial application.

Citrus By-Products as a Valuable Source of Biologically Active Compounds with Promising Pharmaceutical, Biological and Biomedical Potential

Citrus fruits processing results in the generation of huge amounts of citrus by-products, mainly peels, pulp, membranes, and seeds. Although they represent a major concern from both economical and environmental aspects, it is very important to emphasize that these by-products contain a rich source of value-added bioactive compounds with a wide spectrum of applications in the food, cosmetic, and pharmaceutical industries. The primary aim of this review is to highlight the great potential of isolated phytochemicals and extracts of individual citrus by-products with bioactive properties (e.g., antitumor, antimicrobial, antiviral, antidiabetic, antioxidant, and other beneficial activities with health-promoting abilities) and their potential in pharmaceutical, biomedical, and biological applications. This review on citrus by-products contains the following parts: structural and chemical characteristics; the utilization of citrus by-products; bioactivities of the present waxes and carotenoids, essential oils, pectins, and phenolic compounds; and citrus by-product formulations with enhanced biocactivities. A summary of the recent developments in applying citrus by-products for the treatment of different diseases and the protection of human health is also provided, emphasizing innovative methods for bioaccessibility enhancements (e.g., extract/component encapsulation, synthesis of biomass-derived nanoparticles, nanocarriers, or biofilm preparation). Based on the representative phytochemical groups, an evaluation of the recent studies of the past six years (from 2018 to 2023) reporting specific biological and health-promoting activities of citrus-based by-products is also provided. Finally, this review discusses advanced and modern approaches in pharmaceutical/biological formulations and drug delivery (e.g., carbon precursors for the preparation of nanoparticles with promising antimicrobial activity, the production of fluorescent nanoparticles with potential application as antitumor agents, and in cellular imaging). The recent studies implementing nanotechnology in food science and biotechnology could bring about new insights into providing innovative solutions for new pharmaceutical and medical discoveries.

Prebiotic and Anti-Adipogenic Effects of Radish Green Polysaccharide

Radish (Raphanus sativus L.) greens are consumed as a source of nutrition, and their polysaccharides such as rhamnogalacturonan-I possess certain beneficial properties. This study investigated the prebiotic effects of a radish green polysaccharide (RGP) on gut health and obesity. The prebiotic activity of RGP was evaluated based on the pH changes and short-chain fatty acids (SCFAs) concentration. The results showed that 0.5% RGP had a higher prebiotic activity score than inulin and increased SCFAs production in all five prebiotic strains. Moreover, RGP inhibited fat accumulation in 3T3-L1 adipocytes, indicating its potential to reduce obesity. Overall, these findings suggested that the polysaccharide of radish greens has prebiotic effects and may serve as a beneficial prebiotic for gut health and obesity.

Antimicrobial high molecular weight pectin polysaccharides production from diverse citrus peels using a novel PL10 family pectate lyase

The discovery of environmentally friendly enzymes that can convert inexpensive and abundant citrus peel pectin into high value-added product is a potential avenue for the citrus peel application. In this study, a novel PL10-family pectate lyase (pelA) was characterized from marine bacterium Echinicola pacifica. PelA was a Ca²⁺ dependent pectate lyase whose activity was highest at pH 8 and 40 °C. It was capable of degrading polygalacturonic acid (PGA) and citrus peel pectin (CPP), but not apple peel pectin. Notably, PelA hydrolyzed PGA to high molecular weight polysaccharide (average molecular weight 111.4 kDa). Moreover, PelA was also able to degrade CPP from nine distinct citrus species into polysaccharides (average molecular weight ranging from 84.7 to 539.2 kDa) that showed antimicrobial activity against Staphylococcus epidermidis (88.8 %), Bacillus subtilis (99.8 %), Staphylococcus aureus (92.1 %), Escherichia coli (100.0 %) and Klebsiella pneumoniae (86.4 %). Considering the high market value of pectin in the food industry, PelA's capacity to convert citrus pectin into high molecular weight polysaccharides lays a foundation for its applications.

Structural characterization of a novel fucosylated trisaccharide prepared from bacterial exopolysaccharides and evaluation of its prebiotic activity

Fucosylated oligosaccharides have promising prospects in various fields. In this study, a fucosylated trisaccharide (GFG) was separated from the acidolysis products of exopolysaccharides from Clavibacter michiganensis M1. Structural characterization demonstrated that GFG consists of glucose, galactose, and fucose, with a molecular weight of 488 Da. Nuclear magnetic resonance analysis showed that it has a different structure than that of 2'-fucosyllactose (2'-FL), even though they have the same monosaccharide composition. In vitro prebiotic experiments were conducted to evaluate the differences in the utilization of three selected carbohydrates by fourteen bacterial strains. In comparison with 2'-FL, GFG could be utilized by more beneficial bacteria, leading to generate more short-chain fatty acids. Moreover, GFG could not promote the proliferation of Escherichia coli. This work describes a novel fucosylated oligosaccharide and its preparation method, and the obtained trisaccharide may serve as a promising candidate for fucosylated human milk oligosaccharides.

Phytochemicals, Bioactive Properties and Commercial Potential of Calamondin (Citrofortunella microcarpa) Fruits: A Review

The calamondin (Citrofortunella microcarpa) is a hybrid citrus fruit resulting from the crossing of a mandarin orange with a kumquat. It is a small, round-shaped fruit with thin, smooth skin ranging from orange to dark red. The aroma of the fruit is distinctive and unique. Calamondin is an excellent source of Vitamin C, D-Limonene, and essential oils, providing benefits to the immune system, as well as anti-inflammatory, anti-cancer, anti-diabetic, anti-angiogenic, and anti-cancer properties, and it exhibits various therapeutic effects. It also contains a good amount of dietary fiber from pectin. Its distinctive flavor and high juice content make calamondin juice a popular ingredient in many international cuisines. The juice also contains bioactive compounds, such as phenolics and flavonoids, which are a potential source of antioxidant properties. All parts of the calamondin fruit, including the juice, pulp, seeds, and peel, can be used in various applications, from food products like juices, powders, and candies to non-food uses in herbal medicine and cosmetics, showcasing their versatility and unique properties. This review will examine various bioactive components of calamondin and their related medicinal effects, and provide guidelines for their utilization, processing, and value addition on a commercial scale.

A review of citrus plants as functional foods and dietary supplements for human health, with an emphasis on meta-analyses, clinical trials, and their chemical composition

Fruits, flowers, leaves, essential oils, hydrosols, and juices of citrus spp. Are utilized to prepare various forms of food products. Along with their nutritional values, in the health industry, different parts of the plants of the citrus genus have been used as supplements or remedies to prevent or control diseases. This review focused on reported meta-analyses and clinical trials on the health benefits of citrus plants as functional foods. Also, chemical compounds of various citrus species were reviewed. The following information sources were used for data collection: Google Scholar, the Web of Science, Scopus, and PubMed. Various keywords, including "citrus AND chemical compounds," "citrus AND phytochemicals," "citrus species," "citrus AND meta-analysis," "nutritional and therapeutical values of citrus spp.," "clinical trials AND citrus," "clinical trials AND Rutaceae," "health benefits of citrus spp.," "citrus edible or non-edible applications," and scientific names of the citrus plants were utilized to collect data for the review. The scientific name and common name of all twenty-eight citrus species, along with any of the above keywords, were also searched in the mentioned databases. Scientific papers and data sources were sought to review and discuss the citrus plant's nutritional and therapeutic importance. Several meta-analyses and clinical trials have reported beneficial effects of citrus spices on a variety of cancer risks, cardiovascular risk factors, neurologic disorders, urinary tract conditions, and gastrointestinal tract conditions. They have shown anxiolytic, antimicrobial, and pain-alleviating effects. Some of them can be helpful in managing obesity and cardiovascular risk factors.

The Preparation and Potential Bioactivities of Modified Pectins: A Review

Pectins are complex polysaccharides that are widely found in plant cells and have a variety of bioactivities. However, the high molecular weights (M_w) and complex structures of natural pectins mean that they are difficult for organisms to absorb and utilize, limiting their beneficial effects. The modification of pectins is considered to be an effective method for improving the structural characteristics and promoting the bioactivities of pectins, and even adding new bioactivities to natural pectins. This article reviews the modification methods, including chemical, physical, and enzymatic methods, for natural pectins from the perspective of their basic information, influencing factors, and product identification. Furthermore, the changes caused by modifications to the bioactivities of pectins are elucidated, including their anti-coagulant, anti-oxidant, anti-tumor, immunomodulatory, anti-inflammatory, hypoglycemic, and anti-bacterial activities and the ability to regulate the intestinal environment. Finally, suggestions and perspectives regarding the development of pectin modification are provided.

Biologically Active Supplements Affecting Producer Microorganisms in Food Biotechnology: A Review

Microorganisms, fermentation processes, and the resultant metabolic products are a key driving force in biotechnology and, in particular, in food biotechnology. The quantity and/or quality of final manufactured food products are directly related to the efficiency of the metabolic processes of producer microorganisms. Food BioTech companies are naturally interested in increasing the productivity of their biotechnological production lines. This could be achieved via either indirect or direct influence on the fundamental mechanisms governing biological processes occurring in microbial cells. This review considers an approach to improve the efficiency of producer microorganisms through the use of several types of substances or complexes affecting the metabolic processes of microbial producers that are of interest for food biotechnology, particularly fermented milk products. A classification of these supplements will be given, depending on their chemical nature (poly- and oligosaccharides; poly- and oligopeptides, individual amino acids; miscellaneous substances, including vitamins and other organic compounds, minerals, and multicomponent supplements), and the approved results of their application will be comprehensively surveyed.

Anti-obesity effects of red pepper (Capsicum annuum L.) leaf extract on 3T3-L1 preadipocytes and high fat diet-fed mice

Patients with obesity mostly have metabolic syndrome and this can lead to multiple health problems. In the present study, we evaluated the anti-obesity effect of water-soluble red pepper (Capsicum annuum L.) leaf extract (PLE) on 3T3-L1 adipocytes and high-fat diet (HFD)-fed mice. The adipocyte lipid content was determined using Oil Red O staining, which revealed that 100 μg mL^-1 PLE markedly reduced fat accumulation without affecting the cell viability. PLE exhibited high prebiotic activity scores by modulating probiotic strains, contributing to host health improvement. In vivo investigation in HFD-fed mice revealed that PLE supplementation significantly decreased the HFD-induced increases in the body weight, amount of white adipose tissue, and serum triglyceride, total cholesterol, leptin, and insulin levels. Consistent with its effects on reduced lipid droplet formation in the liver, PLE supplementation suppressed the expression of lipid synthesis-related proteins including SREBP-1, FAS, and PPAR-γ in the liver and increased that of PGC-1α, CPT1, and adiponectin in epididymal WAT. PLE treatment improved intestinal barrier function and inflammation and reduced harmful intestinal enzyme activities in the feces. Collectively, these results indicate that PLE inhibits fat accumulation in HFD-fed mice via the suppression of adipogenesis and lipogenesis, suggesting its potential in preventing obesity.

Modulation of the Gut Microbiota Structure and Function by Two Structurally Different Lemon Pectins

Pectins are plant polysaccharides consumed as part of a diet containing fruits and vegetables. Inside the gastrointestinal tract, pectin cannot be metabolized by the mammalian cells but is fermented by the gut microbiota in the colon with the subsequent release of end products including short-chain fatty acids (SCFA). The prebiotic effects of pectin have been previously evaluated but reports are inconsistent, most likely due to differences in the pectin chemical structure which can vary by molecular weight (MW) and degree of esterification (DE). Here, the effects of two different MW lemon pectins with varying DEs on the gut microbiota of two donors were evaluated in vitro. The results demonstrated that low MW, high DE lemon pectin (LMW-HDE) altered community structure in a donor-dependent manner, whereas high MW, low DE lemon pectin (HMW-LDE) increased taxa within Lachnospiraceae in both donors. LMW-HDE and HMW-LDE lemon pectins both increased total SCFAs (1.49- and 1.46-fold, respectively) and increased acetic acid by 1.64-fold. Additionally, LMW-HDE lemon pectin led to an average 1.41-fold increase in butanoic acid. Together, these data provide valuable information linking chemical structure of pectin to its effect on the gut microbiota structure and function, which is important to understanding its prebiotic potential.

A Novel Endo-Polygalacturonase from Penicillium rolfsii with Prebiotics Production Potential: Cloning, Characterization and Application

In this study, a potential producer of prebiotics, a novel endo-polygalacturonase pePGA from Penicillium rolfsii BM-6, was successfully expressed in Komagataella phaffii, characterized and applied to produce pectic oligosaccharides. The optimum temperature and pH of pePGA were 60 °C and 6.0. The purified recombinant enzyme showed a good pH stability and was stable from pH 3.5 to 8.0. The Km, Vmax and kcat values of pePGA were 0.1569 g/L, 12,273 μmol/min/mg and 7478.4 s−1, respectively. More importantly, pePGA-POS, the pePGA hydrolysis products from commercial pectin, had good prebiotic and antibacterial activities in vitro. The pePGA-POS was able to significantly promote the growth of probiotics; meanwhile, the growth of Escherichia coli JM109, Staphylococcus aureus and Bacillus subtilis 168 was effectively inhibited by pePGA-POS. In addition, pePGA-POS also had the DPPH radical scavenging capacity. These properties of pePGA-POS make pePGA attractive for the production of prebiotics.

Effects of different enzyme extraction methods on the properties and prebiotic activity of soybean hull polysaccharides

In this study, five different processes, including hot water (HW-ASP), single enzyme (cellulase, pectinase and papain; C-ASP, PE-ASP, and P-ASP), and compound-enzyme (cellulose: pectinase: papain = 3:3:1; CE-ASP) for the extraction of soybean hull polysaccharides (ASPs) were employed, and the characterization and prebiotics activity of five polysaccharides were analyzed. These polysaccharides possessed different primary structural characteristics, including molecular weight distribution, monosaccharide composition, chemical composition, surface morphology, potential particle size, etc., while similar functional groups. In vitro digestibility assay indicated that C-ASP had strong resistance to gastric juice hydrolysis and α-amylase as compared with HW-ASP. Furthermore, C-ASP elevated the acidifying activity and promoted the growth of probiotics (Lactobacillus paracasei, Lactobacillus rhamnosus, and Lactobacillus acidophilus) during the fermentation (p < 0.05). C-ASP improved the levels of total short-chain fatty acids (SCFAs) and had better prebiotic activity than HW-ASP (p < 0.05). These findings denote that enzyme-assisted polysaccharides extracted from soybean hulls have the potential to be served as novel probiotics.

Current Advancements in Pectin: Extraction, Properties and Multifunctional Applications

Pectin is a heterogeneous hydrocolloid present in the primary cell wall and middle lamella in all dicotyledonous plants, more commonly in the outer fruit coat or peel as compared to the inner matrix. Presently, citrus fruits and apple fruits are the main sources for commercial extraction of pectin, but ongoing research on pectin extraction from alternate fruit sources and fruit wastes from processing industries will be of great help in waste product reduction and enhancing the production of pectin. Pectin shows multifunctional applications including in the food industry, the health and pharmaceutical sector, and in packaging regimes. Pectin is commonly utilized in the food industry as an additive in foods such as jams, jellies, low calorie foods, stabilizing acidified milk products, thickener and emulsifier. Pectin is widely used in the pharmaceutical industry for the preparation of medicines that reduce blood cholesterol level and cure gastrointestinal disorders, as well as in cancer treatment. Pectin also finds use in numerous other industries, such as in the preparation of edible films and coatings, paper substitutes and foams. Due to these varied uses of pectin in different applications, there is a great necessity to explore other non-conventional sources or modify existing sources to obtain pectin with desired quality attributes to some extent by rational modifications of pectin with chemical and enzymatic treatments.

Assessment of the bifidogenic and antibacterial activities of xylooligosaccharide

Xylooligosaccharide (XOS) is an attractive prebiotic mainly due to its bifidogenic effect. However, commercial XOS with different compositions is often applied in the food industry at different doses without specifications. In this study, we evaluated the bifidogenic activity of XOS at different doses with either mixtures or pure fractions with different degrees of polymerization (DP), using three strains of Bifidobacterium spp., including B. breve ATCC 15700, B. bifidum ATCC 29521, and B. animalis subsp. lactis HN019. Three growth indicators showed strain-specific bifidogenic activity of XOS, and the activity was both dose- and fraction-dependent as only certain fractions stimulated significant growth. Adding 0.25% XOS (w/v) also promoted increase in total bifidobacterial population of rat fecal samples fermented in vitro. Albeit the antibacterial activity of XOS fractions can be demonstrated, significant growth inhibition can only be achieved when 4.0% XOS mixture was added in Staphylococcus aureus ATCC 6538 pure culture. In contrast, in the presence of B. lactis HN019, 1.0% XOS showed significant antibacterial activity against S. aureus ATCC 6538 in milk. In addition, RNA sequencing suggested downregulation of genes involved in S. aureus ATCC 6538 infection, pathogenesis, and quorum sensing, by XOS. In conclusion, the report urges scientific specifications on XOS chemistry for its effective application as a novel food ingredient or functional food and provides novel insights into its bifidogenic and antibacterial activities.

Changes of pectin structure and microbial community composition in strawberry fruit (Fragaria × ananassa Duch.) during cold storage

Strawberry is very perishable fruit with rapid postharvest loss of quality and high susceptibility to microbial infections. In this work we study pectin modifications and microbiota and mycobiota composition in strawberry in conventional and organic cultivation systems. The enzymatic activity during postharvest storage of both types of strawberry was divided at the fifth day of storage into two phases: postharvest changes and rotting. Pectin molecules extracted from organic strawberries were longer and more branched compared to the conventional strawberries; however a more noticeable reorganization of molecular structure occurred. The sequential action of the pectinolytic enzymes had a direct effect on the molecular structure of pectin fractions. The observed changes in pectin structure relate to the synergistic activity of pectinolytic enzymes and some microorganisms. The organic system was characterized by a greater number and variety of bacteria and fungi during storage as compared to the conventional system.

De-Oiled Citrus Peels as Feedstock for the Production of Pectin Oligosaccharides and Its Effect on Lactobacillus fermentum, Probiotic Source

Following the extraction of essential oil, citrus (Mousambi, Kinnow, and Orange) peel wastes were used to produce pectin. The yield of essential oil and pectin was maximum in orange. Pectin was characterized by Fourier-transform infrared spectroscopy (FT-IR) and X-ray diffraction (XRD) spectroscopy. The degree of esterification (DE) and methoxyl content (MC) was maximum in orange whereas, the equivalent weight was maximum in Mousambi. A significant increase (61.8%) in the Lactobacillus fermentum population was observed with pectin as compared with sugar. Three sources followed the Orange > Kinnow > Mousambi trend as a prebiotic source. It was attributed to higher DE as well as higher MC. Enhancement in the bacterial population was in the range of 79.16–87.50%. The present work confirms the potential of pectin as a probiotic source for the enhancement of the bacterial population. Thus, it has a large scope for use in the food industry targeting a circular economy.

Preparation, structural characterization and prebiotic potential of mulberry leaf oligosaccharides

The present study shows the purification of a main oligosaccharide fraction (MLO 1-2) from the enzymatic hydrolysate of mulberry leaf polysaccharides by DEAE-52 cellulose and gel column chromatography. The physicochemical properties of MLO 1-2 were characterized. The structure of MLO 1-2 was obtained as follows: α-(2-OAc)-Manp-1 → 2-β-Glcp-1 → 4-β-Glcp-1 → 4-α-Glcp-1 → 2-α-Glcp-1 → 2-α-Galp-1 → 2-β-Galp-1 → 2-β-Galp-1, which was elucidated by methylation and NMR analysis. The molecular weight of MLO 1-2 showed no significant change after simulated saliva, gastric and intestinal digestion. This indicated that MLO 1-2 could pass through the digestive system without being degraded to safely reach the colon to regulate the gut microbiota. Additionally, MLO 1-2, more than glucose or galactooligosaccharides, promoted the proliferation of Bifidobacterium bifidum, B. adolescentis, Lacticaseibacillus rhamnosus and Lactobacillus acidophilus. Furthermore, the acetic and lactic acid concentrations of bacterial cultures inoculated with MLO 1-2 were higher than those inoculated with glucose and galactooligosaccharide (GOS). These results suggest that MLO 1-2 could be an excellent prebiotic for intestinal flora regulation and the promotion of gut health.

Fermentation With Pleurotus Ostreatus Enhances the Prebiotic Properties of Germinated Riceberry Rice

Rice is the staple food for more than half of the world's population. In recent years, awareness of the health benefits of colored rice varieties and germinated rice has gradually increased. Riceberry rice (R), a black-purple variety, was germinated and subsequently fermented with Pleurotus ostreatus mycelium (M) to improve nutrient quality and prebiotic properties. The γ-aminobutyric acid (GABA) and β-glucan contents were measured daily for a total of 4 days. The prebiotic activities of R, germinated Riceberry rice (GR), and germinated Riceberry rice with mycelium (GRM) were evaluated on the probiotic bacteria Pediococcus sp., Lactobacillus acidophilus, and Streptococcus lactis. Results were compared with the M treatment and with the commercial prebiotic agents: inulin and β-glucan. The treatments were also used to evaluate growth of the pathogen Escherichia coli. The GABA content peaked after 3 days of germination. The GR sample fermented with M for 3 days had the optimal concentration of both β-glucan and GABA. Evaluation of the prebiotic properties of rice samples and the commercial standards (inulin and β-glucan) showed that these were enhanced on the GR and GRM treatments. Results also showed the improvement of prebiotic properties on GR as the R sample did not show any prebiotic properties in all probiotic bacteria, whereas the GR sample showed moderate prebiotic activity score of 0.40, 0.88, and 0.56 on Pediococcus sp., L. acidophilus, and S. lactis, respectively. Furthermore, the prebiotic activity of GR was improved when fermented with M. For further applications, the GRM could be used on rice-based products, such as rice flour, rice crackers, or other rice products to enhance nutritional value and improve digestive system health, especially in the elderly.

Structural features and anticancer mechanisms of pectic polysaccharides: A review

The anticancer activity of pectic polysaccharides (PPs) was proved by numerous studies, and which also indicated that the bioactivity of PPs was closely related to its complicated structures. Based on the summary and analysis about structure characteristics and corresponding enzymatic process of the reported PPs, the anticancer mechanism and related structural features were systematically clarified. It was found that not only the direct effects on the cancer cells by proliferation inhibition or apoptosis, but also the regulation of immune system, gut microbiota and gut metabolism as indirect effects, jointly played important roles in the anticancer of PPs. Nevertheless, during the study of PPs as promising anticancer components, the exact structure-function relationship, digestion process in vivo, and comprehensive action mechanism are still not well understanding. With the unveiling of the proposed issues, it is believed that PPs are promising to be exploited as effective cancer therapy/adjunctive therapy drugs or functional foods.

Mango Pectic Oligosaccharides: A Novel Prebiotic for Functional Food

Prebiotics are functional food ingredients that assist probiotic growth and render many other health benefits. Mango peel is the biomass of the processing industry and has recently been value-added as a dietary fiber pectin. Besides its general use as a food additive, mango peel pectin (MPP) is partially hydrolyzed by pectinase to obtain pectic oligosaccharides (POSs) that have recently gained attention as novel prebiotic products and in medical research. This review describes probiotic candidates responsible for the digestion of pectin derivatives and the advantages of POSs as functional additives and their current best retrieval options. Mango pectic oligosaccharide (MPOS) recovery from low methoxyl MPP from mango with prebiotic performance both in vivo and in vitro environments is discussed. Current research gaps and potential developments in the field are also explored. The overall worthiness of this article is the potential use of the cheap-green food processing bioresource for high-value components.

Preventive Effect of Pectic Oligosaccharides on Acute Colitis Model Mice: Modulating Epithelial Barrier, Gut Microbiota and Treg/Th17 Balance

Pectin as dietary fiber supplements has shown emerging potential in clinical ulcerative colitis (UC) adjuvant therapy. In this study, the preventive and prebiotic effect of enzymatic-degraded pectic oligosaccharides (POS) was...

Elucidating the degradation pattern of a new cold-tolerant pectate lyase used for efficient preparation of pectin oligosaccharides

The cold-active pectate lyases have drawn increasing attention in food and biotechnological applications due to their ability to retain high catalytic efficiency under lower temperatures, which could be helpful for energy saving, cost reduction and flavor preservation. Herein, a new cold-tolerant pectate lyase (ErPelPL1) gene from Echinicola rosea was cloned and heterologously expressed in Escherichia coli. Interestingly, ErPelPL1 retained high catalytic activity even at a low temperature (4 °C). ErPelPL1 exhibited optimal activity at 35 ℃, pH 8.0 with 1 mM of Ca2+. It showed high specific activity towards polygalacturonic acid (34.7 U/mg) and sodium polygalacturonate (59.3 U/mg). The combined thin-layer chromatography (TLC), fast protein liquid chromatography (FPLC) and electrospray ionization mass spectrometry (ESI-MS) results indicated that ErPelPL1 endolytically degraded pectic substances into the oligosaccharides with degrees of depolymerization (Dps) of 1-6. In conclusion, this study mainly conducted biochemical characterization and product analysis of a cold-tolerant pectate lyase. Therefore, it provides a promising enzyme candidate for food and biotechnological applications.

In vitro Assessment of Chemical and Pre-biotic Properties of Carboxymethylated Polysaccharides From Passiflora edulis Peel, Xylan, and Citrus Pectin

This study aimed to determine the carboxymethylation effect of crude water-soluble polysaccharides of Passiflora edulis peel (WPEP), xylan (XY), and citrus pectin (CP). Their chemical and pre-biotic properties were also determined. The polysaccharides were carboxymethylated by reacting with chloroacetic acid and sodium hydroxide. The carboxymethylated and non-carboxymethylated polysaccharides were also used as pre-biotics to study the growth pattern of selected intestinal microflora. These polysaccharides substituted the glucose solution in culture media for culturing Lactobacillus brevis GIM1.773, Lactobacillus plantarum GIM1.19, Lactobacillus delbrueckii subsp. bulgaricus GIM1.155, and Streptococcus thermophilus GIM1.540. The results showed that the carboxymethylated polysaccharides c-XY, c-CP, and c-WPEP, had substitution degrees of 0.682, 0.437, and 0.439, respectively. The polysaccharides demonstrated resistance to digestion in the simulated human digestive models. The resistance to digestion was enhanced by carboxymethylation, especially the carboxymethylated CP and WPEP. The results also showed that the pre-biotic activities of the polysaccharides increased after carboxymethylation. The c-XY had a better pre-biotic effect than XY and the other carbohydrate samples. The findings suggested that carboxymethylated polysaccharides may be developed into novel pre-biotics and nutraceuticals that could promote growth of the probiotic strains.

The bioavailability of soybean polysaccharides and their metabolites on gut microbiota in the simulator of the human intestinal microbial ecosystem (SHIME)

The present study aimed to investigate the bioavailability of soybean polysaccharides and their metabolites on gut microbiota in the simulator of the human intestinal microbial ecosystem (SHIME). The effects of soybean polysaccharides on probiotics and pathogenic bacteria were investigated in vitro. Our results showed that soybean polysaccharides were only partially degraded in the oral, gastric, and small intestinal compartments of the SHIME. Moreover, the polysaccharides could be mainly broken down and utilized by the gut microbiota in the colon of the SHIME. Soybean polysaccharides could significantly reduce the ratio of Firmicutes to Bacteroidetes at the phylum level. Therefore, the number of beneficial bacteria were noticeably enhanced, and the pathogenic bacteria were inhibited. Furthermore, soybean polysaccharides promoted the growth of probiotics and improved the ability of these probiotics to inhibit pathogenic bacteria. Therefore, soybean polysaccharides could potentially be functional food to prevent disease by promoting gut health.

Mango Peel Pectin: Recovery, Functionality and Sustainable Uses

Concerns regarding the overconsumption of natural resources has provoked the recovery of biopolymers from food processing biomass. Furthermore, the current market opportunity for pectin in other areas has increased, necessitating the search for alternative pectin resources. This is also a step towards the sustainable and circular green economy. Mango peel is the byproduct of agro-processing and has been used for high value-added components such as polysaccharide biopolymers. Pectin derived from the peel is yet to be exploited to its greatest extent, particularly in terms of its separation and physiochemical properties, which limit its applicability to dietary fiber in culinary applications. The functionality of the mango peel pectin (MPP) strongly depends on the molecular size and degree of esterification which highlight the importance of isolation and characterisation of pectin from this novel resource. This article therefore provides a useful overview of mango peel as a potential biomaterial for the recovery of MPP. Different extraction techniques and the integrated recovery were also discussed. The utilisation of MPP in different industrial schemes are also detailed out from different perspectives such as the pharmaceutical and biotechnology industries. This review convincingly expresses the significance of MPP, providing a sustainable opportunity for food and pharmaceutical development.

New perspectives for banana peel polysaccharides and their conversion to oligosaccharides

Banana peel is a source of polysaccharides: pectin, hemicellulose and cellulose. Recent studies have shown that these carbohydrate fractions can be converted into oligomers, which have applications in food, feed and pharmaceuticals, claiming important technical, functional and biological activities. Potential prebiotic activity of pectin and cellulose oligosaccharides obtained from banana peel was already reported. Based on technologies developed for fractionation and extraction of polysaccharides, such as pectin, hemicellulose and cellulose, banana peel can be explored to obtain functional oligosaccharides.

A method for quantitative characterization of incomplete degradation products of polygalacturonic acid

Biological activity of incomplete degradation products of polygalacturonic acid (IDPP) is closely related to its molecular weight and molecular weight distribution. Therefore, it is necessary to provide a reliable quantitative characterization method for evaluating these types of bioproducts. A novel method was established in this work for the quantitative characterization of IDPP based upon ethanol fractional precipitation. IDPP was fractionated into several fractions with high recovery (>95%), and the average molecular weights of each fraction was in descending order with the increase of ethanol concentration. Oligosaccharides (polymerization degree: 2-20) could be effectively harvested from the polygalacturonic acid enzymatic hydrolysate by ethanol precipitation. Moreover, the developed method had good repeatability and could also be applied to quantify enzymatic hydrolysis products of citrus-derived pectin polysaccharides. In conclusion, this paper provides a simple, accurate method for the quantitative characterization of IDPP and a strategy for the extraction of oligosaccharides.

Characterization of Citrus Pectin Oligosaccharides and Their Microbial Metabolites as Modulators of Immunometabolism on Macrophages

We characterized the structure of prepared citrus pectin oligosaccharides (POS) and investigated the immunometabolism-modulating effects of POS and their microbial metabolites on human macrophages. Both POS and metabolites activated immune responses and exhibited anti-inflammatory properties in the presence of lipopolysaccharide (LPS) via regulating expressions of inflammatory cytokines and nuclear factor-kappa B. Cholesterol efflux was also facilitated via increased gene expressions of the liver X receptor-α-adenosine triphosphate-binding cassette transporter (ABC) A1/ABCG1 pathway and suppressed cholesterol synthesis via suppressing expressions of 3-hydroxy-3-methylglutaryl-coenzyme A reductase. Microbial degradation prevented POS from attenuating palmitoyl-3-cysteine-serine-lysine-4-induced inflammation and promoting M2 polarization, but it is capable of inhibiting cholesterol uptake-related genes CD36 and SR-A. These findings indicate that immunometabolism-modulating effects of POS are not solely microbiota-dependent effects. Both POS and their microbial metabolites are potential immunometabolism modulators via different mechanisms.