Pectic oligosaccharides: Manufacture and functional properties

Structural insights and therapeutic potential of plant-based pectin as novel therapeutic for type 2 diabetes mellitus: A review

Type 2 diabetes mellitus (T2DM) is a global health challenge with limited efficacy of current treatments, necessitating alternative therapies. Plant-derived pectin, composed of galacturonic acid and structural domains such as homogalacturonan, has shown promise as an anti-diabetic agent. Pectin exerts its therapeutic effects through multiple mechanisms, including enhancing β-cell function, regulating glucose metabolism, improving insulin sensitivity, inhibiting digestive enzymes, and restoring gut microbiota balance. Its bioactivity is influenced by physicochemical properties like molecular weight, degree of methylation, and structural complexity. This review explores the anti-diabetic potential of pectin, its structure-activity relationships, and mechanisms of action, providing insights for its development as a novel therapeutic agent in T2DM management.

Effects of Standardized Natural Citrus Extract on Growth, Gut Health, Carcass Quality, and Welfare of Broiler Chickens

This study aimed to investigate the effects of a Standardized Natural Citrus Extract (SNCE) on broiler chickens' growth performance, gut health, carcass quality, and welfare. A total of 756 one-day-old Ross 308 males were randomly assigned to two groups: a control group (CTL) fed with a standard diet, and a citrus group (SNCE) fed with the same standard diet supplemented with 250 g/ton of feed of SNCE. Growth performance was recorded weekly until d 35, while mortality was recorded daily. The feed conversion ratio (FCR) and European Efficiency Index (EEI) of broiler chickens were also calculated weekly. At day 35, 10 birds per group were randomly selected for slaughter performance. In parallel, broiler chickens' welfare was assessed according to the Welfare Quality Assessment Protocol. Caecal digest was also collected post mortem for short-chain fatty acids (SCFA) analyses, and jejunum samples were collected for ex vivo gut permeability assay. SNCE dietary supplementation enhanced broiler chickens' performance, i.e., final bodyweight and EEI, compared to the CTL group. The carcass weight was also significantly higher in the SNCE group. In addition, the fat percentage was lower in the SNCE group. Regarding broiler chickens' welfare and gut health parameters, Footpad Dermatitis (FPD) and gate score were also lower in birds supplemented with SNCE. The SCFA measurement showed a lower concentration of iso-butyric acid, iso-valeric acid, and total putrefactive SCFA in the SNCE group. The differences in gut permeability measured as TEER value indicate that using citrus extract lowered the risk of gut inflammation. This study provides valuable insights into the mechanisms of action that may underlie the observed effects of SNCE on performance, as demonstrated in this study and others. These effects could potentially be attributed to the reduction in inflammation and the enhanced utilization of nutrients. Further studies are needed to confirm these results.

Roles of Probiotics, Prebiotics, and Postbiotics in B-Cell-Mediated Immune Regulation

Probiotics, prebiotics, and postbiotics can significantly influence B-cell-related diseases through their immunomodulatory effects. They enhance the immune system's function, particularly affecting B cells, which originate in the bone marrow and are crucial for antibody production and immune memory. These substances have therapeutic potential in managing allergies, autoimmune diseases, and inflammatory conditions by regulating the gut microbiota, strengthening epithelial barriers, and directly interacting with various components of the innate and adaptive immune systems. The review highlights the critical need for further research into the precise mechanisms through which probiotics, prebiotics, and postbiotics modulate B cells. Gaining this understanding could facilitate the development of more effective treatments for B-cell-related diseases by harnessing the immunomodulatory properties of these dietary components.

The Molecular Weight of Enzymatically Modified Pectic Oligosaccharides from Apple Pomace as a Determinant for Biological and Prebiotic Activity

The purpose of this research was to investigate the prebiotic effects of different fractions of pectin-derived oligosaccharides (POSs) from apple pomace (AP) in relation to their molecular weight (MW), structure, and composition. Enzymatic treatment of the apple pomace resulted in high-molecular-weight arabinans and rhamnogalacturonans (MW 30-100 kDa, MW 10-30 kDa), as well as oligomeric fractions with molecular weights of less than 10 kDa, consisting mainly of homogalacturonan. The biological potential of the POSs against various lactobacilli and bifidobacteria was evaluated. The oligosaccharides with the highest molecular weights (MW 30-100 kDa, MW 10-30 kDa) showed better prebiotic effect to lactobacilli. The oligosaccharides with MW 3-10 kDa and MW 10-30 kDa caused an increase in the bifidogenic effect. Inhibition of Escherichia coli, Salmonella enterica serovar Typhimurium, and Listeria monocytogenes was also observed. The preparations with MW 3-10 kDa and MW 10-30 kDa demonstrated the strongest biological activity, supporting the adhesion of beneficial microorganisms to mucin and collagen surfaces. Therefore, oligosaccharides with MW 10-30 kDa were considered to be the most promising prebiotic candidates. This study confirms that the biological effects of pectic oligosaccharides vary significantly based on their structural differences. Therefore, the conditions of enzymatic hydrolysis of apple pectin should be optimized to obtain oligosaccharides within a specific molecular mass range.

Structure and degradation dynamics of dietary pectin

Pectin, a complex dietary fiber, constitutes a key structural component of the cell walls of numerous edible plant products. It is resistant to digestion by human enzymes and undergoes depolymerization and saccharification in the gastrointestinal tract through the action of carbohydrate-active enzymes (CAZymes) produced by gut microbiota. This enzymatic breakdown generates intermediate structural fragments, which are subsequently converted into pectin oligosaccharides (POS) and monosaccharides. POS exhibit prebiotic properties and have demonstrated potential health benefits, including anti-carcinogenic effects, mucoadhesive capabilities, and the promotion of beneficial gut bacterial growth. However, the current understanding of the molecular structure of pectin and its degradation dynamics remains fragmented within the literature, impeding progress in dietary fiber intervention research and the development of personalized nutrition approaches. This review aims to provide a comprehensive overview of the structural features of pectin and the intricate breakdown mechanisms orchestrated by CAZymes. It underscores the complex architecture of pectin that influences its breakdown dynamics and specifies the enzymatic requirements for the cleavage of its diverse structural components. These insights complement our accompanying review on the structure-function relationships between pectin and the human gut microbiota, previously published in this journal.

Beetroot juice intake positively influenced gut microbiota and inflammation but failed to improve functional outcomes in adults with long COVID: A pilot randomized controlled trial

BACKGROUND & AIMS

Long-term effects of coronavirus disease 2019 (long COVID) develop in a substantial number of people following an acute COVID-19 episode. Red beetroot juice may have positive effects on multiple pathways involved in long COVID. The aim of this pilot study was to explore the impact of beetroot juice supplementation on physical function, gut microbiota, and systemic inflammation in adults with long COVID.

METHODS

A single-center, double-blind, placebo-controlled randomized trial was conducted to test the effects of 14 days of beetroot juice supplementation, rich in nitrates and betalains, on functional and biological outcomes in adults aged between 20 and 60 years with long COVID. Participants were randomized 1:1 to receive either daily oral supplementation with 200 mL beetroot juice (∼600 mg nitrate) or placebo (∼60 mg nitrate) for 14 days. The primary endpoint was the change from baseline to day 14 in a fatigue resistance test. Secondary outcomes included the distance walked on the 6-min walk test, handgrip strength, and flow-mediated dilation. Secondary endpoints also included changes from baseline in circulating inflammatory mediators and metagenomic and fecal water metabolomic profiles. Partial least squares discriminant analysis (PLS-DA) models were built to evaluate the differences in biological variables associated with the interventions.

RESULTS

Thirty-one participants were randomized in the study. Twenty-five of them (median (interquartile range) age 40 (10), 14 [56 %] women), received either beetroot juice (15) or placebo (10) and completed the study. At 14 days, fatigue resistance significantly improved from baseline (mean difference [standard error]: +21.8 [3.7] s; p < 0.001) with no significant differences between intervention groups. A significant increase from baseline in the distance walked on the 6-min walk test was observed (mean difference [standard error]: +30.0 [9.4] m; p = 0.03), which was not different between groups. Flow-mediated dilation did not differ between participants who received beetroot juice and those on placebo. PLS-DA models allowed correct classification of participants with 92.2 ± 4.4 % accuracy. Those who ingested red beetroot juice had a greater abundance of bacteria with well-known beneficial effects, including Akkermansia, Oscillospira, Prevotella, Roseburia, Ruminococcaceae, and Turicibacter, compared with placebo. Participants allocated to beetroot juice supplementation were also characterized by significantly higher levels of fecal nicotinate, trimethylamine, and markers of beetroot juice intake (e.g., 5,6-dihydroxyindole). Finally, higher levels of interferon gamma and macrophage inflammatory protein-1β were found in participants who consumed beetroot juice.

CONCLUSION

Beetroot juice supplementation for two weeks did not to induce significant improvements in functional outcomes in adults with long COVID compared with placebo. Beneficial effects were observed in both gut microbiota composition (i.e., increase in probiotic species) and inflammatory mediators.

TRIAL REGISTRATION

Trial was registered under ClinicalTrials.gov. Identifier no. NCT06535165.

The ruminant gut microbiome vs enteric methane emission: The essential microbes may help to mitigate the global methane crisis

Ruminants release enteric methane into the atmosphere, significantly increasing greenhouse gas emissions and degrading the environment. A common focus of traditional mitigation efforts is on dietary management and manipulation, which may have limits in sustainability and efficacy, exploring the potential of essential microorganisms as a novel way to reduce intestinal methane emissions in ruminants; a topic that has garnered increased attention in recent years. Fermentation and feed digestion are significantly aided by essential microbes found in the rumen, such as bacteria, fungi, and archaea. The practical implications of the findings reported in various studies conducted on rumen gut concerning methane emissions may pave the way to understanding the mechanisms of CH4 production in the rumen to enhance cattle feed efficiency and mitigate CH4 emissions from livestock. This review discussed using essential bacteria to reduce intestinal methane emissions in ruminants. It investigates how particular microbial strains or consortia can alter rumen fermentation pathways to lower methane output while preserving the health and productivity of animals. We also describe the role of probiotics and prebiotics in managing methane emissions using microbial feed additives. Further, recent studies involving microbial interventions have been discussed. The use of new methods involving functional metagenomics and meta-transcriptomics for exploring the rumen microbiome structure has been highlighted. This review also emphasizes the challenges faced in altering the gut microbiome and future directions in this area.

Harnessing Prebiotics to Improve Type 2 Diabetes Outcomes

The gut microbiota, a complex ecosystem of microorganisms in the human gastrointestinal tract (GI), plays a crucial role in maintaining metabolic health and influencing disease susceptibility. Dysbiosis, or an imbalance in gut microbiota, has been linked to the development of type 2 diabetes mellitus (T2DM) through mechanisms such as reduced glucose tolerance and increased insulin resistance. A balanced gut microbiota, or eubiosis, is associated with improved glucose metabolism and insulin sensitivity, potentially reducing the risk of diabetes-related complications. Various strategies, including the use of prebiotics like inulin, fructooligosaccharides, galactooligosaccharides, resistant starch, pectic oligosaccharides, polyphenols, β-glucan, and Dendrobium officinale have been shown to improve gut microbial composition and support glycemic control in T2DM patients. These prebiotics can directly impact blood sugar levels while promoting the growth of beneficial bacteria, thus enhancing glycemic control. Studies have shown that T2DM patients often exhibit a decrease in beneficial butyrate-producing bacteria, like Roseburia and Faecalibacterium, and an increase in harmful bacteria, such as Escherichia and Prevotella. This review aims to explore the effects of different prebiotics on T2DM, their impact on gut microbiota composition, and the potential for personalized dietary interventions to optimize diabetes management and improve overall health outcomes.

The pectin metabolizing capacity of the human gut microbiota

The human gastrointestinal microbiota, densely populated with a diverse array of microorganisms primarily from the bacterial phyla Bacteroidota, Bacillota, and Actinomycetota, is crucial for maintaining health and physiological functions. Dietary fibers, particularly pectin, significantly influence the composition and metabolic activity of the gut microbiome. Pectin is fermented by gut bacteria using carbohydrate-active enzymes (CAZymes), resulting in the production of short-chain fatty acids (SCFAs) such as acetate, propionate, and butyrate, which provide various health benefits. The gastrointestinal microbiota has evolved to produce CAZymes that target different pectin components, facilitating cross-feeding within the microbial community. This review explores the fermentation of pectin by various gut bacteria, focusing on the involved transport systems, CAZyme families, SCFA synthesis capacity, and effects on microbial ecology in the gut. It addresses the complexities of the gut microbiome's response to pectin and highlights the importance of microbial cross-feeding in maintaining a balanced and diverse gut ecosystem. Through a systematic analysis of pectinolytic CAZyme production, this review provides insights into the enzymatic mechanisms underlying pectin degradation and their broader implications for human health, paving the way for more targeted and personalized dietary strategies.

Gut microbiota modulatory capacity of fermented ketchup in a validated in vitro model of the colon

This study aimed to evaluate the effects of fermented beetroot ketchup enriched with Lactobacillus johnsonii K4 and non-fermented beetroot ketchup on pooled fecal microbiota from healthy adults in in vitro colon model. The research focused on how these products influenced the composition and functionality of the gut microbiota, as well as metabolite production, using the validated dynamic in vitro colon model, TNO Intestinal Model (TIM-2). After an initial starvation phase, a single 60 g dose of predigested and freeze-dried ketchup was introduced into the model. The potential probiotic strain Lactobacillus johnsonii K4 was added over three days. A carbohydrate mixture of standard ileal effluent medium (SIEM) served as the control. Our analysis identified 21 bacterial taxa that were significantly modulated (q-value < 0.2) when comparing ketchup samples to control samples. Notably, the ketchup samples led to an increase in butyrate-producing taxa, including Faecalibacterium, Blautia, Ruminococcaceae, Ruminiclostridium 6, and Anaerostipes. Conversely, there was a reduction in potentially pathogenic genera Desulfovibrio and Escherichia-Shigella. Distinct profiles of short-chain fatty acids (SCFA) were observed among the fermented ketchup, non-fermented ketchup, and control samples. Non-fermented ketchup resulted in higher proportions of acetate, propionate, and butyrate compared to the other interventions. This may be related to the fermentation with lactic acid bacteria in fermented samples with lower levels of substrate for SCFAs production. However, fermented ketchup sample has higher relative abundance of beneficial bacteria like Lactobacillus, Weissella and Dorea in gut microbiota. These findings suggest that beetroot ketchup, can positively influence gut microbiota composition and function, highlighting its potential benefits for human health.

Optimization of Pectin Extraction from Melon Peel as a New Source of Pectin and Pectin Hydrolysate with Prebiotic Potential

Food wastes have a large number of functional ingredients that have potential for valorization. Melon peels are increasingly produced as waste in food industries in Thailand. This study aimed to optimize pectin extraction conditions from melon peel for its prebiotic potential. Optimization was conducted using a response surface methodology and Box-Behnken experimental design. An analysis of variance indicated a significant interaction between the extraction conditions on extraction yield and degree of esterification (DE). These include pH and solvent-to-sample ratio. The conditions for the extraction of pectin with low DE (LDP), medium DE (MDP) and high DE (HDP) were optimized. Pectin hydrolysate from LDP, MDP and HDP was prepared by enzymatic hydrolysis into LPEH, MPEH and HPEH, respectively. LDP, MDP, HDP, LPEH, MPEH and HPEH were compared for their efficiency in terms of the growth of three probiotic strains, namely Lactobacillus plantarum TISTR 877, Lactobacillus casei TISTR 390 and Enterococcus faecium TISTR 1027. Among the samples tested, HPEH showed the highest ability as a carbon source to promote the growth and prebiotic activity score for these three probiotic strains. This study suggests that melon peel waste from agro-industry can be a novel source for prebiotic production.

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.

Pectic oligosaccharides: enzymatic preparation, structure, bioactivities and application

Pectic oligosaccharides have become novel bioactive components. However, the comprehensive preparation methods, structural features, bioactivities and application of them lack a systematic review. Here, we focused on the enzymatic preparation of pectic oligosaccharides, and attempted to outline relationships among the enzymolysis condition, structure, bioactivities and application of pectic oligosaccharides. Pectic oligosaccharides were characterized by the oligosaccharides with units of →4)-α-GalpA-(1→4)-α-GalpA-(1→ or →4)-α-GalpA-(1→2)-α-Rhap-(1→. Enzymatic method was the most suitable approach for pectic oligosaccharides preparation that was significantly affected by the enzyme's type, time and concentration. Besides, pectic oligosaccharides possessed various bioactivities including prebiotic, anti-glycosylation, antioxidant, anticancer and lipid metabolism-regulation activities, which were closely associated with the molecular weight, the structure of side chain and the monosaccharide composition. Especially, many pectic oligosaccharides with low molecular weight demonstrated high prebiotic activities, and those with arabinogalactan side chains exhibited strong anticancer activities. Moreover, pectic oligosaccharides have been used in food preservatives, dairy product additives and food processing aids. Nevertheless, the industrial application, novel technology exploration, and structure-bioactivity relationship of pectic oligosaccharides remain a demanding and significant task for future work.

Dietary pectin attenuates Salmonella typhimurium-induced colitis by modulating the TLR2-NF-κB pathway and intestinal microbiota in mice

The role of dietary pectin on microbial-induced colitis, oxidative status, barrier function, and microbial composition, as well as the underlying mechanisms, is scarce. In this study, we aimed to investigate whether dietary pectin alleviates Salmonella typhimurium-induced colitis in mice. Male C57BL/6J mice fed an isocaloric and isofibrous diet with 7% pectin or cellulose were administered sterile water or Salmonella typhimurium to induce colitis, which is equal to a human food dose of 0.57% (5.68 g/kg). Dietary pectin alleviated Salmonella typhimurium-induced colitis and oxidative stress as shown by the reduced disease activity index score, decreased colon shortening and histological damage score, colonic hydrogen peroxide, malondialdehyde concentrations, and relative mRNA expressions of coenzyme Q-binding protein COQ10 homologue B (Coq10b), Ccl-2, Ccl-3, Ccl-8, Tnf-α, Il-1β, Ifn-γ, Ifn-β, and serum TNF-α protein level. Moreover, pectin administration ameliorated the downregulated colonic abundances of occludin, zonula occludens-1, zonula occludens-2, and the upregulated abundances of TLR2 and p-NF-κB in Salmonella-infected mice. Additionally, 16S rRNA analysis demonstrated that pectin altered the microbial beta-diversity and reduced Salmonella levels. Collectively, pectin ameliorated Salmonella typhimurium-induced colitis, oxidative stress, and tight junction, which may be related to the inactivation of TLR2-NF-κB signalling and reduced abundance of Salmonella.

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.

Complete genome sequence of pectin-degrading Flavobacteriaceae bacterium GSB9

Pectic oligosaccharides, which are considered to be potential prebiotics, may be generated by pectin-degrading enzymes. Here, we report the complete genome sequence of the pectin-degrading marine bacterium, Flavobacteriaceae bacterium GSB9, which was isolated from seawater of South Korea. The complete genome sequence revealed that the chromosome was 3,630,376 bp in size, had a G + C content of 36.6 mol%, and was predicted to encode 3100 protein-coding sequences (CDSs), 40 tRNAs, and six 16S-23S-5S rRNAs. Genome sequence analysis revealed that this strain possesses multiple genes predicted to encode pectin-degrading enzymes. Our analysis may facilitate the future application of this strain against pectin in various industries.

Space exposure enhanced pectin-degrading enzymes expression and activity in Aspergillus costaricaensis

Aspergillus is a well-studied fungal genus that is widely used in the processing of plant biomass in industries. This study investigated the effects of space exposure on the ability of Aspergillus costaricaensis, a filamentous fungus isolated from rotten orange peel, to degrade pectin. These fungal spores were carried into space by the Long March 5B carrier rocket and exposed to cosmic radiation for 79 h. After the flight, these spores were resuscitated, and then the growing strains were screened with pectin as the sole carbon source, and the pectinase activity was evaluated. A mutant with increased biomass accumulation ability and pectin-degrading activity compared to the ground control strain was obtained. Comparative transcriptome analysis revealed that several CAZymes genes were significantly upregulated in the mutant, especially those related to pectin degradation. Among the 44 pectinases identified from the annotated genome, 42 were up-regulated. The activities of these pectinases are able to synergistically break down the structure of pectin. In addition, the expression of some genes involved in metabolism, sugar transport, and stress response was altered. These results imply that space exposure might serve as a potential mutagenesis breeding technique, offering the opportunity to acquire biomass-degrading microbial strains with potential for industrial application.

Improving the specific activity and stability of alkaline pectinase PEL3 through SpyTag/SpyCatcher cyclization

OBJECTIVES

PEL3, an alkaline pectinase, exhibited the highest activity among documented alkaline pectate lyases reported in our early study. Unfortunately, undesired thermal stability hampering its industrial application. The purpose of this study is to enhance the performance of wild-type PEL3 (W-PEL3) based on SpyTag/SpyCatcher-mediated cyclization.

RESULTS

The cyclized PEL3 (C-PEL3) was observed to fold correctly and generate a spatial conformation in a head-to-tail manner in E. coli. C-PEL3 exhibited comparable optimum pH and temperature to those of W-PEL3. Moreover, the catalytic activity of C-PEL3 increased by 23% compared to W-PEL3, and the k_cat/K_m of C-PEL3 was 1.5-fold greater than that of the W-PEL3. Importantly, C-PEL3 showed improved stability compared to W-PEL3. Firstly, C-PEL3 displayed a 65% increase in residual activity after treatment at 55 °C for 30 min. Secondly, C-PEL3 was prone to resist heat-induced protein aggregation. Thirdly, C-PEL3 exhibited metal ion stability. Circular dichroism analysis revealed that C-PEL3 was more capable of maintaining its secondary structures than W-PEL3 upon heat treatment.

CONCLUSIONS

C-PEL3, the initial example of a circular pectinase through SpyTag/SpyCatcher cyclization, exhibits superior performance and represents a highly encouraging contender for industrial utilization.

Xylanopectinolytic enzymes by marine actinomycetes from sediments of Sarena Kecil, North Sulawesi: high potential to produce galacturonic acid and xylooligosaccharides from raw biomass

BACKGROUND

Actinomycetes isolated from marine habitats are known to have the potential for novel enzymes that are beneficial in the industry. In-depth knowledge is necessary given the variety of this bacterial group in Indonesia and the lack of published research. Actinomycetes isolates (BLH 5-14) obtained from marine sediments of Sarena Kecil, Bitung, North Sulawesi, Indonesia, showed an ability to produce pectinase and xylanase that have equal or even higher potential for pectic-oligosaccharides (POS) and xylooligosaccharides (XOS) production from raw biomass than from commercial substrates. This study's objective was to characterize both enzymes to learn more for future research and development.

RESULTS

Pectinase had the highest activity on the 6^th day (1.44±0.08 U/mL) at the optimum pH of 8.0 and optimum temperature of 50 °C. Xylanase had the maximum activity on the 6^th day (4.33±0.03 U/mL) at optimum pH 6.0 and optimum temperature 60 °C. Hydrolysis and thin layer chromatography also showed that pectinase was able to produce monosaccharides such as galacturonic acid (P1), and xylanase was able to yield oligosaccharides such as xylotriose (X3), xylotetraose (X4), and xylopentaose (X5). BLH 5-14 identified as the genus Streptomyces based on the 16S rDNA sequences and the closely related species Streptomyces tendae (99,78%).

CONCLUSIONS

In the eco-friendly paper bleaching industry, Streptomyces tendae has demonstrated the potential to create enzymes with properties that can be active in a wide range of pH levels. The oligosaccharides have the potential as prebiotics or dietary supplements with anti-cancer properties. Further research is needed to optimize the production, purification, and development of the application of pectinase and xylanase enzymes produced by Actinomycetes isolates.

Structure characteristics of low molecular weight pectic polysaccharide and its anti-aging capability by modulating the intestinal homeostasis

Pectic polysaccharide has attracted increasing attention for their potential biological properties and applications in health industries. In this study, a low-molecular-weight pectic polysaccharide, POS4, was obtained from citrus peel. The structure of POS4 was preliminarily analyzed by gel-permeation chromatography, monosaccharide analysis, infrared spectroscopy (IR) and nuclear magnetic resonance spectroscopy (NMR). Results showed that the molecular weight of POS4 was 4.76 kDa and it was a galacturonic acid enriched pectic polysaccharide. The anti-aging activity in vivo showed that POS4 could notably prolong the average lifespan of fruit flies by suppressing the generation of reactive oxygen species (ROS). Further studies demonstrated that POS4 could enhance intestinal homeostasis by modulating gut microbiota in a positive way and regulating autophagy associated genes. Taken together, we proposed that galacturonic acid enriched low molecular weight pectic polysaccharide have great potential in the development of healthy foods such as anti-aging health care products.

Fine characterization and microbiota assessment as keys to understanding the positive effect of standardized natural citrus extract on broiler chickens

The objective of this study was to investigate the effect and composition of a standardized natural citrus extract (SNCE) on both broiler chickens' growth performances and intestinal microbiota. A total of 930 one-day-old males were randomly assigned to three dietary treatments: a control treatment (CTL) in which broiler chickens were fed with a standard diet and two citrus treatments in which broiler chickens were fed with the same standard diet supplemented with 250 ppm and 2,500 ppm of SNCE, respectively. Each dietary treatment was composed of 10 experimental units (pen) of 31 broiler chickens each. Growth performances such as feed consumption, body weight, and feed conversion ratio (FCR) were recorded weekly until day 42. Litter quality was also weekly recorded while mortality was daily recorded. One broiler chicken was randomly selected from each pen (10 chickens/group) and ceca samples were collected for microbiota analysis at day 7 and 42. Chromatographic methods were used to determine molecules that enter into the composition of the SNCE. Results from the characterization of SNCE allowed to identify pectic oligosaccharides (POS) as a major component of the SNCE. In addition, 35 secondary metabolites, including eriocitrin, hesperidin, and naringin, were identified. The experiment performed on broiler chickens showed that the final body weight of broiler chickens fed diets supplemented with SNCE was higher than those fed the CTL diets (P < 0.01). Broiler cecal microbiota was impacted by age (P < 0.01) but not by the dietary supplementation of SNCE. Results indicate that SNCE allowed enhancing chickens' performances without any modulation of the cecal microbiota of broiler chickens. The characterization of SNCE allowed to identify compounds such as eriocitrin, naringin, hesperidin, and POS. Thus, opening new horizons for a better understanding of the observed effect on broiler chickens' growth performances.

Mind the Pulp: Environmental and economic assessment of a sugar beet pulp biorefinery for biobased chemical production

Sugar beet pulp, a byproduct from sugar beet refining, is used by farmers as fertilizer or sold as animal feed. Both options underestimate the potential of sugar beet pulp as a platform to produce specialty and bulky chemicals as a promising pathway for sustainable biochemicals - mind the pulp. This study proposes a biorefinery concept to produce food additives (pectin-derived oligosaccharides) and bulky chemicals (terephthalic acid). Since the biorefinery has a low technology readiness level (TRL = 1), it is relevant to evaluate the feasibility of this biorefinery concept to provide guidance (at an early stage) on the environmental and economic advantages and limitations. For this purpose, the life cycle assessment and techno-economic assessment frameworks are used to assess the environmental impact and economic performance of the biobased terephthalic acid, respectively. Moreover, environmental impacts are accounted for in economic terms using different monetary valuation methods (environmental prices, Ecovalue12, and Ecotax). The environmental impact of biobased terephthalic acid was higher in most impact categories than the fossil counterpart, depending on the selected allocation approach (mass vs economic). The economic feasibility of the proposed biorefinery is highly dependent on the pectin-derived oligosaccharides market price and the valorization of byproducts (humins and levulinic acid). The selection of the monetary valuation method is critical for monetizing environmental impacts when comparing biobased against fossil-based alternatives.

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 Lycium barbarum Polysaccharides on Immunity and Metabolic Syndrome Associated with the Modulation of Gut Microbiota: A Review

Lycium barbarum polysaccharides (LBPs) have attracted increasing attention due to their multiple pharmacological activities and physiological functions. Recently, both in vitro and in vivo studies have demonstrated that the biological effects of dietary LBPs are related to the regulation of gut microbiota. Supplementation with LBPs could modulate the composition of microbial communities, and simultaneously influence the levels of active metabolites, thus exerting their beneficial effects on host health. Interestingly, LBPs with diverse chemical structures may enrich or reduce certain specific intestinal microbes. The present review summarizes the extraction, purification, and structural types of LBPs and the regulation effects of LBPs on the gut microbiome and their derived metabolites. Furthermore, the health promoting effects of LBPs on host bidirectional immunity (e.g., immune enhancement and immune inflammation suppression) and metabolic syndrome (e.g., obesity, type 2 diabetes, and nonalcoholic fatty liver disease) by targeting gut microbiota are also discussed based on their structural types. The contents presented in this review might help to better understand the health benefits of LBPs targeting gut microbiota and provide a scientific basis to further clarify the structure-function relationship of LBPs.

Potential of pectin for biomedical applications: a comprehensive review

Pectin is a polysaccharide extracted from various plants, such as apples, oranges, lemons, and it possesses some beneficial effects on human health, including being hypoglycemic and hypocholesterolemic. Therefore, pectin is used in various pharmaceutical and biomedical applications. Meanwhile, its low mechanical strength and fast degradation rate limit its usage as drug delivery devices and tissue engineering scaffolds. To enhance these properties, it can be modified or combined with other organic molecules or polymers and/or inorganic compounds. These materials can be prepared as nano sized drug carriers in the form of spheres, capsules, hydrogels, self assamled micelles, etc., for treatment purposes (mostly cancer). Different composites or blends of pectin can also be produced as membranes, sponges, hydrogels, or 3D printed matrices for tissue regeneration applications. This review is concentrated on the properties of pectin based materials and focus especially on the utilization of these materials as drug carriers and tissue engineering scaffolds, including 3D printed and 3D bioprinted systems covering the studies in the last decade and especially in the last 5 years.

An Updated Review on Prebiotics: Insights on Potentials of Food Seeds Waste as Source of Potential Prebiotics

Prebiotics are a group of biological nutrients that are capable of being degraded by microflora in the gastrointestinal tract (GIT), primarily Lactobacilli and Bifidobacteria. When prebiotics are ingested, either as a food additive or as a supplement, the colonic microflora degrade them, producing short-chain fatty acids (SCFA), which are simultaneously released in the colon and absorbed into the blood circulatory system. The two major groups of prebiotics that have been extensively studied in relation to human health are fructo-oligosaccharides (FOS) and galactooligosaccharides (GOS). The candidature of a compound to be regarded as a prebiotic is a function of how much of dietary fiber it contains. The seeds of fruits such as date palms have been reported to contain dietary fiber. An increasing awareness of the consumption of fruits and seeds as part of the daily diet, as well as poor storage systems for seeds, have generated an enormous amount of seed waste, which is traditionally discarded in landfills or incinerated. This cultural practice is hazardous to the environment because seed waste is rich in organic compounds that can produce hazardous gases. Therefore, this review discusses the potential use of seed wastes in prebiotic production, consequently reducing the environmental hazards posed by these wastes.

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.

Structural characterization of polysaccharides from Geranium sanguineum L. and their immunomodulatory effects in response to inflammatory agents

ETHNOPHARMACOLOGICAL RELEVANCE

Geranium sanguineum L. is used for treatment of inflammations, anemia, malignant diseases of the blood-forming organs, diarrhea, respiratory infections, etc. Only flavonoids in root extracts have been elucidated as immunostimulating and anti-inflammatory compounds, and polysaccharides in the herb have not been examined.

AIM OF THE STUDY

to compare the chemical features of polysaccharide complexes (PSCs) from leaves (GSL-PSC) and roots (GSR-PSC) of G. sanguineum, as well as their immunomodulatory activities on leukocytes after inflammation, and effects on the growth of different bacteria.

MATERIALS AND METHODS

The samples were isolated by water extraction and their structural features were studied by 2D NMR spectroscopy. The stimulatory effects of both PSCs on human leukocytes were analyzed with flow cytometry. Their suppressive activities on the oxidative burst in blood and derived neutrophils against opsonized zymosan and phorbol myristate acetate were investigated. The effects of the samples on viability, NO and interleukin 6 (IL-6) syntheses in RAW264.7 cells after inflammation with lipopolysaccharides (LPS) were tested. The prebiotic and anti-biofilm activities of the PSCs were evaluated.

RESULTS

The total carbohydrate content in the samples was significant (73.6-76.8%). GSL-PSC contained pectins, which were rich in homogalacturonan (HG), and smaller amounts of rhamnogalacturonan (RG) type I, decorated by 1,5-α-L-Araf, 1,4- and 1,6-β-D-Galp chains. GSR-PSC contained starch, followed by pectins with lower HG content and more RG-I regions, substituted by 1 → 3,5-α-L-arabinans and 1 → 3,6-β-D-galactans. GSL-PSC and GSR-PSC (200 μg/mL) increased monocyte and granulocyte cell counts, but GSR-PSC also elevated T helper and B cell levels in a normal and activated state. GSR-PSC triggered a dose-dependent (50-200 μg/mL) oxidative burst in blood, but alleviated it after inflammation even in blood-derived neutrophils. It was free of LPS, and activated NO and IL-6 productions in RAW264.7 cells better than GSL-PSC, without affecting their viability. Both PSCs (2.0%, w/v) stimulated probiotic co-cultures between Clostridium beijerinckii strains and Lactobacillus sp. ZK9, and inhibited the growth and biofilm formation of Escherichia coli, Streptococcus mutans and Salmonella enterica.

CONCLUSIONS

The PSs in G. sanguineum could be involved in the stimulatory effects on blood-forming organs and anti-inflammatory action of aqueous root extracts in case of infections. These PSs should be included in synbiotic foods to support the treatment of inflammations and infections in the gut.

Engineering and screening of novel β-1,3-xylanases with desired hydrolysate type by optimized ancestor sequence reconstruction and data mining

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A novel integrative strategy for engineering β-1,3-xylanases with desired products.

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AncXyl10 is the first successful example of ASR to shift the hydrolysate types.

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The hydrolysates of AncXyl10 was only β-1,3-xylobiose and β-1,3-xylotriose.

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The underlying mechanism laid a new groundwork towards hydrolase engineering.

Engineering of hydrolases to shift their hydrolysate types has not been attempted so far, though computer-assisted enzyme design has been successful. A novel integrative strategy for engineering and screening the β-1,3-xylanase with desired hydrolysate types was proposed, with the purpose to solve problems that the separation and preparation of β-1,3-xylo-oligosaccharides was in high cost yet in low yield as monosaccharides existed in the hydrolysates. By classifying the hydrolysate types and coding them into numerical values, two robust mathematical models with five selected attributes from molecular docking were established based on LogitBoost and partial least squares regression with overall accuracy of 83.3% and 100%, respectively. Then, they were adopted for efficient screening the potential mutagenesis library of β-1,3-xylanases that only product oligosaccharides. The virtually designed AncXyl10 was selected and experimentally verified to produce only β-1,3-xylobiose (60.38%) and β-1,3-xylotriose (39.62%), which facilitated the preparation of oligosaccharides with high purity. The underlying mechanism of AncXyl10 may associated with the gap processing and ancestral amino acid substitution in the process of ancestral sequence reconstruction. Since many carbohydrate-active enzymes have highly conserved active sites, the strategy and their biomolecular basis will shield a new light for engineering carbohydrates hydrolase to produce specific oligosaccharides.

Prebiotics as a Tool for the Prevention and Treatment of Obesity and Diabetes: Classification and Ability to Modulate the Gut Microbiota

Diabetes and obesity are metabolic diseases that have become alarming conditions in recent decades. Their rate of increase is becoming a growing concern worldwide. Recent studies have established that the composition and dysfunction of the gut microbiota are associated with the development of diabetes. For this reason, strategies such as the use of prebiotics to improve intestinal microbial structure and function have become popular. Consumption of prebiotics for modulating the gut microbiota results in the production of microbial metabolites such as short-chain fatty acids that play essential roles in reducing blood glucose levels, mitigating insulin resistance, reducing inflammation, and promoting the secretion of glucagon-like peptide 1 in the host, and this accounts for the observed remission of metabolic diseases. Prebiotics can be either naturally extracted from non-digestible carbohydrate materials or synthetically produced. In this review, we discussed current findings on how the gut microbiota and microbial metabolites may influence host metabolism to promote health. We provided evidence from various studies that show the ability of prebiotic consumption to alter gut microbial profile, improve gut microbial metabolism and functions, and improve host physiology to alleviate diabetes and obesity. We conclude among other things that the application of systems biology coupled with bioinformatics could be essential in ascertaining the exact mechanisms behind the prebiotic–gut microbe–host interactions required for diabetes and obesity improvement.

Application of prebiotics in apple products and potential health benefits

Among the fruits, the apple stands out among the most used for elaboration of processed foods. However, the importance of prebiotics in apple products has never been widely analyzed. Prebiotic is a food component resistant to gastric acidity, digestion by mammalian enzymes and gastrointestinal absorption. But following fermentation in the colon, prebiotics result in specific changes in the composition and / or metabolism of the gastrointestinal microbiota, conferring benefits to the health of the host. Therefore, fortifying apple-based products with additional prebiotics is an important strategy for improving consumer health benefits. In this review, after compiling and analyzing scientific and technological studies focusing on prebiotics in apple products, the following benefits of these prebiotics became evident: (1) reduction of water loss in the food matrix; (2) preservation of bioactive and volatile compounds; (3) texture improvement (thickening) in the food industry; (4) increased shelf-live and (5) increased survival of probiotic bacteria, promoting positive effects on microbiota. In addition, this review shows the benefits of different prebiotics for stability and sensory acceptance of apple processed foods.

Effect of pectin oligosaccharides supplementation on infant formulas: The storage stability, formation and intestinal absorption of advanced glycation end products

Pectin oligosaccharides with a molecular weight greater than 700 Da was obtained from the pomace of kiwi (Actinidia arguta). Based on characteristics analysis and inhibitory activity of advanced glycation end products (AGEs) formation in vitro, the target pectin oligosaccharides was added to infant formulas and then subjected to accelerated storage. Results showed that pectin oligosaccharides supplementation inhibited the browning of infant formulas and glassy transition of lactose, and slowed down the increase of water activity under accelerated storage conditions. Pectin oligosaccharides also inhibited the formation of AGEs in infant formulas, such as 5-(hydroxymethyl)furfural, N^ε-carboxymethyl-lysine, N^ε-carboxyethyl-lysine, methylglyoxal hydromidazolones, glyoxal hydromidazolones, glyoxal-lysine dimer, methylglyoxal-lysine dimer and pyrraline. Besides, permeability studies using Caco-2 cell monolayer also showed that pectin oligosaccharides supplementation inhibited the intestinal absorption of AGEs, especially 5-(hydroxymethyl)furfural, Nε-carboxymethyl-lysine, Nε-carboxyethyl-lysine and glyoxal hydromidazolones. These results provide a reliable theoretical basis for the application of pectin oligosaccharides in infant formulas.

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.

Valorization of sugar beet pulp to value-added products: A review

The processing of sugar beet in the sugar production industry releases huge amounts of sugar beet pulp as waste which can be considered a valuable by-product as a source of cellulose, hemicellulose, and pectin. Valorization of sugar beet pulp into value added products occurs through acid hydrolysis, hydrothermal techniques, and enzymatic hydrolysis. Biochemical conversion of beet pulp into simple fermentable sugars for producing value added products occurs through enzymatic hydrolysis is a cost effective and eco-friendly process. While beet pulp has predominantly been used as a fodder for livestock, recent developments in its biotechnological valorization have unlocked its value as a feedstock in the production of biofuels, biohydrogen, biodegradable plastics, and platform chemicals such as lactic acid, citric acid, alcohols, microbial enzymes, single cell proteins, and pectic oligosaccharides. This review brings forward recent biotechnological developments made in the valorization of sugar beet pulp into valuable products.

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.

Enzymatic extraction of pectic oligosaccharides from finger citron (Citrus medica L. var. sarcodactylis Swingle) pomace with antioxidant potential

Finger citron pomace is a cheap and renewable by-product of the citrus processing industry, representing up to 60% of the fruit biomass. In this study, a pectinase-based and ultrasonic-assisted method was firstly used to extract pectic oligosaccharides (POS) from finger citron pomace. Using the orthogonal experiment design (OED), the maximum conversion rate of up to 64.5% from pomace to POS was obtained under the extraction conditions of 0.25 mg mL^-1 pectinase and 50 mg mL^-1 pectin at 45 °C and pH 4.5 for 2 h. The extracted POS was then fractionated and purified to homogeneous oligosaccharides (FCPOS-1) with a molecular weight of 2.15 kDa, and the analyses of monosaccharide composition, FTIR, NMR and ESI-MS indicated that FCPOS-1 consisted of GalA and a small amount of mannose, galactose and arabinose. Multiple antioxidant activity assays in vitro revealed that FCPOS-1 possessed remarkable antioxidant properties, especially scavenging activity against DPPH radicals up to 94.07%. FCPOS-1 has the potential to be an effective natural antioxidant for applications in the food and pharmaceutical industries.

The Dietary Fiber Pectin: Health Benefits and Potential for the Treatment of Allergies by Modulation of Gut Microbiota

Purpose of Review

The incidence of allergies is increasing and has been associated with several environmental factors including westernized diets. Changes in environment and nutrition can result in dysbiosis of the skin, gut, and lung microbiota altering the production of microbial metabolites, which may in turn generate epigenetic modifications. The present review addresses studies on pectin-mediated effects on allergies, including the immune modulating mechanisms by bacterial metabolites.

Recent Findings

Recently, microbiota have gained attention as target for allergy intervention, especially with prebiotics, that are able to stimulate the growth and activity of certain microorganisms. Dietary fibers, which cannot be digested in the gastrointestinal tract, can alter the gut microbiota and lead to increased local and systemic concentrations of gut microbiota-derived short chain fatty acids (SCFAs). These can promote the generation of peripheral regulatory T cells (T_reg) by epigenetic modulation and suppress the inflammatory function of dendritic cells (DCs) by transcriptional modulation.

The dietary fiber pectin (a plant-derived polysaccharide commonly used as gelling agent and dietary supplement) can alter the ratio of Firmicutes to Bacteroidetes in gut and lung microbiota, increasing the concentrations of SCFAs in feces and sera, and reducing the development of airway inflammation by suppressing DC function.

Summary

Pectin has shown immunomodulatory effects on allergies, although the underlying mechanisms still need to be elucidated. It has been suggested that the different types of pectin may exert direct and/or indirect immunomodulatory effects through different mechanisms. However, little is known about the relation of certain pectin structures to allergies.

Pectins and Olive Pectins: From Biotechnology to Human Health

Simple Summary

Pectins comprise complex polysaccharides rich in galacturonic acid, that exert many functions in higher plants as components of the cell walls, together with cellulose or lignin. The food industry has traditionally used pectins as an additive due to their gelling or thickening properties. Pharmaceutical research is also taking advantage of pectin bioactivity, providing evidence of the role of these polysaccharides as health promoters. Fruits and vegetables are natural sources of pectins that can be obtained as by-products during food or beverage production. In line with this, the aim of our study is gathering data on the current methods to extract pectins from fruit or vegetable wastes, optimizing yield and environmentally friendly protocols. Updated information about pectin applications in food or non-food industries are provided. We also point to olives as novel source of pectins that strengthen the evidence that this fruit is as remarkably healthy part of the Mediterranean diet. This work exhibits the need to explore natural bioactive components of our daily intake to improve our health, or prevent or treat chronical diseases present in our society.

Abstract

Pectins are a component of the complex heteropolysaccharide mixture present in the cell wall of higher plants. Structurally, the pectin backbone includes galacturonic acid to which neutral sugars are attached, resulting in functional regions in which the esterification of residues is crucial. Pectins influence many physiological processes in plants and are used industrially for both food and non-food applications. Pectin-based compounds are also a promising natural source of health-beneficial bioactive molecules. The properties of pectins have generated interest in the extraction of these polysaccharides from natural sources using environmentally friendly protocols that maintain the native pectin structure. Many fruit by-products are sources of pectins; however, owing to the wide range of applications in various fields, novel plants are now being explored as potential sources. Olives, the fruit of the olive tree, are consumed as part of the healthy Mediterranean diet or processed into olive oil. Pectins from olives have recently emerged as promising compounds with health-beneficial effects. This review details the current knowledge on the structure of pectins and describes the conventional and novel techniques of pectin extraction. The versatile properties of pectins, which make them promising bioactive compounds for industry and health promotion, are also considered.

Dietary inclusion of watermelon rind powder and Lactobacillus plantarum: Effects on Nile tilapia's growth, skin mucus and serum immunities, and disease resistance

An eight-week investigation was conducted to access the potential impact of dietary watermelon rind powder (WMRP) and L. plantarum CR1T5 (LP) administered individually or in combination on immunity, disease resistance, and growth rate of Nile tilapia fingerlings cultured in a biofloc system. Three hundred twenty fish (average weight 16.57 ± 0.14 g) were distributed into 16 tanks at a rate of 20 fish per tank. The fish were fed different diets: Diet 1 (0 g kg^-1 WMRP and 0 CFU g^-1 L. plantarum) (control), Diet 2 (40 g kg^-1 WMRP), Diet 3 (10⁸ CFU g^-1 LP), and Diet 4 (40 g kg^-1 WMRP + 10⁸ CFU g^-1 LP) for eight weeks. A completely randomized design (CRD) with four replications was applied. Skin mucus, serum immunity, and growth parameters were analyzed every 4 weeks, and a challenge study against S. agalactiae was conducted at the end of the experiment. The findings showed that the inclusion of WMRP + LP, administrated individually or in a mixture, significantly (P<0.05) stimulated growth, skin mucus, and serum immune parameters of Nile tilapia fingerlings compared with the control. The highest values were detected in fish fed the combination of WMRP and LP, as opposed to individual administration of either WMRP or LP, in which no significant differences were detected. Within the challenge study, the relative percent survival (RPS) in Diet 2, Diet 3, and Diet 4 was 48.0%, 52.0%, and 68.0%, respectively. Fish fed 40 g kg^-1 WMRP + LP produced significantly higher RPS and protection against S. agalactiae than the other treated groups. Current results suggest that the dual administration of WMRP and LP maybe an effective feed additive for Nile tilapia grown in an indoor biofloc system, capable of improving growth parameters and increasing resistance to S. agalactiae infection.