Pectin-derived Oligosaccharides Research Articles

Ultrasonication and enzymatic treatment of apple and orange bagasses: Molecular characterization of released oligosaccharides and modification of techno-functional and health-related properties

Apple and orange bagasse were subjected to ultrasonication (US) and subsequent enzymatic hydrolysis (EH) with a cellulase-pectinase mixture. US did not affect oligosaccharide profile and water and oil holding capacities (WHC/OHC) in both substrates but enhanced bile acid adsorption capacity (BAC) and total phenolic content (TPC) in orange bagasse. EH increased glucose/xylose and xylobiose (XOS-2) contents and caused the release of cellobiose (COS-2) and pectin derived oligosaccharides (POS), mainly methylated oligogalacturonides with degree of polymerization (DP) 3–4. Hydrolyzed orange bagasse exhibited higher total POS content (31.56 g/100 g bagasse) than apple bagasse (21.13 g/100 g bagasse), but apple bagasse showed higher diversity in methylated and acetylated POS. After combined treatment, POS quantities in apple bagasse were enhanced whereas in orange bagasse COS-2 and POS-2 formation significantly increased, making physical opening before enzymatic degradation an effective strategy for maximizing oligosaccharide concentrations. EH decreased techno-functional properties and TPC but led to a 24.9 % increase of BAC in apple bagasse and a 7.8 % increase in orange bagasse, highlighting that the efficacy of US and EH depends on the applied DF substrate. This study offers guidance for selecting modification technologies for fruit by-products to obtain ingredients with elevated oligosaccharide content, improved techno-functional and health-related properties.

Prebiotic potential of pectin and cello-oligosaccharides from apple bagasse and orange peel produced by high-pressure homogenization and enzymatic hydrolysis

Apple bagasse and orange peel were subjected to high-pressure homogenization (HPH), enzymatic hydrolysis (EH) and their combination (HPHE) to study their effect on oligosaccharide production and in vitro fermentability. The application of a cellulase-pectinase mixture on the by-products generated significant quantities of cellobiose (COS-2) and pectin derived oligosaccharides (POS) which were identified as mainly methylated and acetylated oligogalacturonides with DP 2–5 (POS 2–5). When pre-treating the substrates with HPH, the release in orange peel was enhanced significantly leading to a POS content of 44.51 g/100 g peel, whereas oligosaccharide solubilization in apple bagasse was not affected. In vitro fermentation of the hydrolysates containing COS-2 and POS showed faster fermentation rates, between 6 and 10 h, and enhanced gas production, compared to those samples not subjected to enzymatic hydrolysis. Short chain fatty acid (SCFA) production was not impacted by the presence of POS and COS-2 in the induced quantities.

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.

Influence of glycosyl composition on the immunological activity of pectin and pectin-derived oligosaccharide

Factors causing differences in immune activities between pectin and pectin-derived oligosaccharides have not been fully studied. In this article, four samples with different molecular weights and monosaccharide compositions, including polygalacturonic acid (poly-GA) and its oligosaccharide (oligo-GA), navel orange peel pectin (NP) and its oligosaccharide (oligo-NP), were used to compare their immunomodulatory properties on RAW264.7 cells. All samples had nontoxic effect on cells, oligo-GA and oligo-NP could increase the production of nitric oxide and cytokines to a much higher level than poly-GA and NP. The findings revealed that reducing the molecular weight and preserving the branched regions of pectin-derived samples could improve their immune-enhancing effects on macrophages. Interestingly, the addition of TAK-242 (TLR4 inhibitor) also demonstrated that the tested pectin oligosaccharides could stimulate the activation of macrophages through TLR4 signaling pathway. These results confirmed the potential value of pectin oligosaccharides, and provided theoretical support for their application in the pharmaceutical industry.

Influence of Human Age on the Prebiotic Effect of Pectin-Derived Oligosaccharides Obtained from Apple Pomace

The aim of this study was to evaluate the prebiotic effect of pectin-derived oligosaccharides (POS) obtained from apple pomace on the growth and metabolism of microbiota from the human gastrointestinal tract as a function of the age of the host. The counts of major bacterial groups Bifidobacterium sp., lactobacilli, Clostridium sp., Bacteroides sp., Enterococcus sp. and Enterobacteria were assessed during long-term in vitro fermentation of mixed cultures in a prebiotic medium. Comparative assessment of bacterial diversity in the human fecal microbiota was performed relative to the age of the host, from childhood to old age, through younger years and middle age. The age group of the host was found to be an important factor that determined the prebiotic effect of POS, which was related to both the qualitative and quantitative composition of fecal microbiota and its metabolism. In contrast to the microbiota of elderly subjects, the child-derived intestinal microbiota underwent significantly different alterations in terms of the proportion and composition of lactic acid bacteria, leading to a more favorable pattern of short-chain fatty acids (SCFA) and lactic acid levels.

The purification of pectin from commercial fruit flours results in a jaboticaba fraction that inhibits galectin-3 and colon cancer cell growth

Fruits are a prime source of nutrients, bioactive compounds, and dietary fibers. Some products available on the Brazilian market use fruit by-products and claim to have useful effects on human health due to their dietary fiber content. The study aimed to extract and purify the total (28–47 w/w yield) and soluble dietary fiber (4–7 w/w yield) from jaboticaba, papaya, and plum commercial flours sold in Brazil and to study the in vitro biological effects of the fractions. The purified water-soluble fractions consisted mainly of pectin-derived oligosaccharides (5–15 KDa molecular weight) with a negligible content of polyphenols, protein, ashes, and starch. Jaboticaba sample was 95% galacturonic acid while plum and papaya samples were 40% galacturonic acid and 40% galactose (mol%), approximately. The samples were tested for recombinant human galectin-3 inhibition and changes in the cell viability of human colorectal cancer cells. Only the jaboticaba sample inhibited galectin-3 and decreased HCT116 cell viability after 48 h of treatment (p ≤ 0.01) while the plum sample decreased the cell viability after 24 h treatment (p ≤ 0.05). The results obtained in this study demonstrate the relationship between the structure of the soluble fibers extracted from jaboticaba flour and the possible beneficial effects of their consumption.

Combined Yeast Cultivation and Pectin Hydrolysis as an Effective Method of Producing Prebiotic Animal Feed from Sugar Beet Pulp

An effective and ecological method for liberation of pectin-derived oligosaccharides (POS) from sugar beet pulp (SBP) was developed using enzymatic and microorganism-mediated biomass conversion. The POS may be applied in the production of prebiotic feed additives. Various yeast strains were screened for their capacity for protein synthesis and monosaccharide assimilation. Combined yeast cultivation and pectin hydrolysis were found to be an effective method of producing prebiotics. Separate enzymatic hydrolysis and fermentation of SBP resulted in the release of 3.6 g of POS per 100 g d.w., whereas the yield of POS acquired after the combined process was 17.9% higher, giving 4.2 g of POS per 100 g d.w. Introducing the yeast into the process improved hydrolysis performance due to lower enzyme inhibition by mono- and disaccharides. The prebiotic effect of the POS was assessed by in vitro fermentation using individual cultures of gastrointestinal bacteria. The POS in the SBP hydrolysate effectively promoted the growth of lactobacilli and bifidobacteria. A large increase in adherence to Caco-2 cells in the presence of POS was noted for beneficial Lactobacillus brevis strains, whereas pathogenic bacteria and yeast (C. albicans, C. lusitanie, C. pelliculosa), responsible for infections in breeding animals, showed much weaker adhesion.

Development of a continuous-flow system for microwave-assisted extraction of pectin-derived oligosaccharides from food waste

This paper addresses the current lack of a scalable process for the extraction of “hairy” pectins to upcycle biomasses, by describing the design methodology, building and testing of a continuous microwave-assisted process for potato waste pectin extraction. Hairy pectins have been shown to present prebiotic activity. Conventional pectin extraction methods are not suitable to produce them, as they lead to degradation of hairy regions, in part due to long heating times. Microwave heating is considered an alternative due to its selective and rapid heating. The 2 kW single mode system developed in this study achieved good temperature control of ±2.5 °C, and a stable target temperature in ≈1 min processing time at a feed flow rate of 250 mL min−1. Pectin yields of 40–45% (indicated by the galacturonic acid content) were achieved, with a feed residence time of only 0.81 s followed by 20 min cooling-down under stirring. These yields were 59.75% higher on average than control experiments in batch conditions or under continuous heating. This indicates that a short heating time is sufficient to allow pectin hydrolysis, after which the rate limiting diffusion step can proceed during cool-down, minimising pectin degradation caused by prolonged exposure to high temperatures. The presence of hairy pectin regions in the extract was confirmed by neutral sugar analysis. The high starch content in potato necessitated a de-starching procedure. A sieving procedure was implemented, which removed more starch than enzymatic de-starching, resulting in a higher purity pectin extract and the ability to collect starch as a separate value stream. This work proves the suitability of microwaves to be used as a fast heating method to extract pectin from biomass, avoiding degradation, using a scalable continuous mode of operation.

Structurally Different Pectic Oligosaccharides Produced from Apple Pomace and Their Biological Activity In Vitro.

This study set out to identify the composition and the biological activity of pectin-derived oligosaccharides (POS) generated from mild acid or enzymatic hydrolysis of apple pomace (AP). The effect of the polymerization of the structural units of POS contained in the AP hydrolysate on the growth and metabolism of microbiota from the human gastrointestinal tract and the adhesion of lactic acid bacteria (LAB) or pathogens to human gut epithelial cells was investigated in vitro. Mild acid hydrolysis followed by pectinolysis with Rohapect MaPlusT yielded the highest concentration of POS. In contrast, pure enzymatic processing of the AP performed with a mixed preparation of cellulase and Rohapect MaPlusT resulted in 1.8-fold lower overall POS. The concentration of higher-order oligosaccharides (degree of polymerization (DP) 7–10), however, was 1.7-fold higher. The increased ratio of higher-order oligosaccharides caused an increase in the bifidogenic effect, as well as affecting the amount and nature of short-chain fatty acid produced. Inhibition of Enterobacteriaceae was also observed. The strongest stimulation of LAB adhesion to the human epithelial cells occurred in the presence of the preparation containing the highest concentration of higher-order oligosaccharides. The fecal bacteria and pathogens showed much weaker adhesion to intestinal cells in the presence of all the tested AP hydrolysates. Both of the tested POS preparations, containing structurally different oligosaccharides (DPs 2–10 with different ratios of higher-order oligosaccharides), have the potential to be used as prebiotics for humans and animals. They stimulate bowel colonization with lactic acid bacteria and inhibit the development of infections caused by pathogens.

Pectin-derived neoglycolipids: Tools for differentiation of Shiga toxin subtypes and inhibitors of Shiga toxin-mediated cellular injury

Gut pathogenic enterohemorrhagic Escherichia coli (EHEC) release Shiga toxins (Stxs) as major virulence factors, which bind to globotriaosylceramide (Gb3Cer, Galα1-4 Galβ1-4Glcβ1-1Cer) on human target cells. The aim of this study was the production of neoglycolipids (neoGLs) using citrus pectin-derived oligosaccharides and their application as potential inhibitors of Stxs. The preparation of neoGLs starts with the reduction of the carboxylic acid group of the pectic poly(α1-4)GalUA core structure to the corresponding alcohol, followed by hydrolytic cleavage of resulting poly(α1-4)Gal into (α1-4)Galn oligosaccharides and their linkage to phosphatidylethanolamine (PE). Thin-layer chromatography overlay assays of the produced (α1-4)Galn-PE and corresponding Amadori (α1-4)Galn=PE neoGLs revealed distinguishable binding patterns for Stx1a, Stx2a, and Stx2e. Furthermore, prepared neoGLs protected Vero cells against the cytotoxic action of Stxs when applied as multivalent glycovesicles. The produced neoGLs are applicable for differentiation of Stx subtypes and represent a promising approach to combat infections of EHEC by blocking their major toxins.

Apple pectin-derived oligosaccharides produce carbon dioxide radical anion in Fenton reaction and prevent growth of Escherichia coli and Staphylococcus aureus

Pectin is the main soluble fiber in apples or citruses. It may be fermented by gut microbiota to metabolites showing local intestinal and systemic effects. A wide range of beneficial effects of dietary pectin includes impacts on the redox milieu and microbiota profile. We prepared pectin-derived oligosaccharides (apple (APDO) and citrus) and polygalacturonic acid-derived oligosaccharides, using alkaline hydrolysis by hydrogen peroxide, and analyzed them by Fourier Transform Infrared spectrometry. Furthermore, we analyzed the effects of pectin-derived oligosaccharides on hydroxyl radical (HO)-generating Fenton reaction using electron paramagnetic resonance spin-trapping spectroscopy, and the effects on the growth of Escherichia coli and Staphylococcus aureus in the presence of dietary-relevant HO-generating system (iron+ascorbate). The oligosaccharides react with HO radical to produce carbon dioxide radical anion (CO2−). A comparative analysis showed that APDO has the most prominent bacteriostatic effect. This might be at least partially related to the higher capacity of APDO to produce CO2−, which specifically targets proteins and appears to have a longer lifetime and larger diffusion radius in biological systems compared to HO.

Environmental assessment of biorefinery processes for the valorization of lignocellulosic wastes into oligosaccharides

The European Commission is adopting strategies in order to “closing the loop” of product life cycles in industrial production systems through better recycling and re-use under the perspective of circular economy. One of the most relevant goals in the application of this approach is to convert low-value side streams into more valuable products. In this sense, the conversion of lignocellulosic biomass into biofuels and chemicals is a major challenge not only from the technological but also from the economic and environmental perspectives.In this study, the production of pectin-derived oligosaccharides (POS) from sugar beet pulp (SBP) was environmentally assessed by means of the Life Cycle Assessment methodology under a cradle-to-gate approach. Two different scenarios at pilot scale were considered: Scenario 1 based on conventional autohydrolysis at high temperature and Scenario 2 based on enzymatic hydrolysis.The outcomes of this environmental study are highly dependent on the production yield of the target compounds (POS) and the valorisation strategy considered. In fact, the POS yield of the autohydrolysis approach is around 20% higher than in the enzymatic one. According to the results, Scenario 1 reports the worst results when a functional unit based on the amount of valorised material (100 kg of oven-dried SBP) is considered. However, the profile entirely changes when a unit based on the economic revenue (1 €) is managed. Therefore, attention should be paid on the selection of the functional unit since decision making strategies should highly depend on it.Without waiting for the opportunity to conduct LCA of already-developed processes of the biorefinery system, the development of new alternatives must be carried out with sustainability in mind. Accordingly, the proposal of valorisation strategies for secondary streams should include the analysis of the environmental impacts associated to each alternative, even at the pilot plant stage.

Enzymatic production of pectin-derived oligosaccharides from sugar beet pulp as a component of animal feed

Enzymatic production of pectin-derived oligosaccharides from sugar beet pulp as a component of animal feed

Modification of citrus and apple pectin by power ultrasound: Effects of acid and enzymatic treatment

Pectin-derived oligosaccharides are emerging as a new generation of functional ingredients with new or improved technological and/or bioactive properties as compared to pectin. This work addresses the impact of power ultrasound (US) on the structure of citrus and apple pectin under different experimental conditions of power, amplitude and pectin concentration in aqueous and acid media, as well as in the presence of a pectinase. Results indicated that depolymerisation of both pectin increased with time and intensity of US in aqueous media and their polydispersity decreased. In general, a higher depolymerisation was observed in pectin treated by US in the presence of nitric and citric acids than in water, and hardly any difference was detected between both types of acids. Most of the assays gave rise to high-methoxylated pectin with a degree of esterification above 50%, pointing out their suitability for potential gelling agents. Finally, US did not have any impact in assisted enzymatic hydrolysis on the degree and/or rate of depolymerisation at low and medium levels of pectin concentration (0.5 and 2%), whereas a higher diversity of pectin fragments was found at 5% which could be indicative of a more controlled depolymerisation. These findings highlight the importance of the selection of appropriate US processing conditions to diversify the applications of modified pectin, as well as the potential of US as a prospective alternative to currently used depolymerisation techniques.

Exogenous application of pectin-derived oligosaccharides to grape berries modifies anthocyanin accumulation, composition and gene expression

Anthocyanins are secondary metabolites synthesized in grape berry skins via the phenylpropanoid pathway, with functions ranging from skin coloration to protection against pathogens or UV light. Accumulation of these compounds is highly variable depending on genetics, environmental factors and viticultural practices. Besides their biological functions, anthocyanins improve wine quality, as a high anthocyanin content in berries has a positive impact on the color, total phenolic concentration and, ultimately, the price of wine. The present work studies the effect of the pre-veraison application of pectin derived oligosaccharides (PDO) on the synthesis and accumulation of these compounds, and associates the changes observed with the expression of key genes in the phenylpropanoid pathways. To this end, pre-veraison Cabernet Sauvignon bunches were treated with PDO to subsequently determine total anthocyanin content, the anthocyanin profile (by HPLC-DAD) and gene expression (by qRT-PCR), using Ethrel and water treatments for comparison. The results show that PDO were as efficient as Ethrel in generating a significant rise in total anthocyanin content at 30 days after treatment (dat), compared with water treatments (1.32, 1.48 and 1.02 mg e.Mv-3G/g FW respectively) without any undesirable effect on berry size, soluble solids, tartaric acid concentration or pH. In addition, a significant alteration in the anthocyanin profile was observed. Specifically, a significant increase in the relative concentration of malvidin was observed for both PDO and Ethrel treatments, compared with water controls (52.8; 55.0 and 48.3%, respectively), with a significant rise in tri-hydroxylated forms and a fall in di-hydroxylated anthocyanins. The results of gene expression analyses suggest that the increment in total anthocyanin content is related to a short term increase in phenylalanine ammonia-lyase (PAL) expression, mediated by a decrease in MYB4A expression. A longer term increase in UDP-glucose flavonoid 3-O-glucosyltransferase (UFGT) expression, probably mediated by a rise in MYBA1 was also observed. Regarding the anthocyanin profile, despite the increase observed in MYB5A expression in PDO and Ethrel treatments, no changes in flavonoid 3′-hydroxylase (F-3′-H); flavonoid 3′5′-hydroxylase (F-3′5′-H) or O-methyltransferase (OMT) could be related with the profile modifications described. Overall, this study highlights that application of PDO is a novel means of altering specific grape berry anthocyanins, and could be a means of positively influencing wine quality without the addition of agrochemicals.

Production of pectin‐derived oligosaccharides from lemon peels by extraction, enzymatic hydrolysis and membrane filtration

AbstractBACKGROUNDThere is growing interest in the search for new prebiotics with improved functional properties. In this field, pectin‐derived oligosaccharides (POS) have been identified as promising prebiotics. Lemon peels (an abundant agro‐industrial by‐product) can be used as a raw material for manufacturing a variety of POS, whose prebiotic properties depend on their chemical structure and composition. This work deals with the production of POS by partial enzymatic hydrolysis under a variety of operational conditions, with their purification by membrane filtration and detailed chemical characterisation.RESULTSAs a result of a three‐stage process (water extraction, enzymatic hydrolysis and membrane filtration), two POS refined concentrates were obtained after 7.5 or 24 h of enzymatic hydrolysis (the contents of the non‐volatile impurities were 5.8 and 11.8 wt%, respectively), mainly made up of oligogalacturonides with different molar mass distribution and degree of methylation (43.4 and 37.4%, respectively) and degree of acetylation (5.5 and 8.6%, respectively) at yields of 13.1 and 10.8 g 100 g−1 dry lemon peel wastes, respectively.CONCLUSIONA high‐yield process (based on simple and scalable technologies) enabled the production of two POS mixtures with different chemical characteristics, fulfilling the compositional requirements to be used as prebiotics. © 2014 Society of Chemical Industry

Pectin-modifying enzymes and pectin-derived materials: applications and impacts

Pectins are complex branched polysaccharides present in primary cell walls. As a distinctive feature, they contain high amount of partly methyl-esterified galacturonic acid and low amount of rhamnose and carry arabinose and galactose as major neutral sugars. Due to their structural complexity, they are modifiable by many different enzymes, including hydrolases, lyases, and esterases. Their peculiar structure is the origin of their physicochemical properties. Among others, their remarkable gelling properties make them a key additive for food industries. Pectin-degrading enzymes and -modifying enzymes may be used in a wide variety of applications to modulate pectin properties or produce pectin derivatives and oligosaccharides with functional as well as nutritional interests. This paper reviews the scientific information available on pectin structure, pectin-modifying enzymes, and the use of enzymes to produce pectin with controlled structure or pectin-derived oligosaccharides, with functional or nutritional interesting properties.

Pectic Oligosacharides from Lemon Peel Wastes: Production, Purification, and Chemical Characterization

Lemon peel wastes were extracted with water to remove free sugars and other soluble compounds, and the insoluble solid was employed as a substrate for the manufacture of pectin-derived oligosaccharides by processing with hot, compressed water. When water-extracted lemon peel wastes were treated with water at 160 °C, the oligomer concentration reached the maximum value (31 g/L). Autohydrolysis liquors were subjected to two membrane filtration stages (diafiltration followed by concentration), yielding a refined product containing about 98 wt % of oligomers at a global yield of 14 kg/100 kg oven-dry lemon peel. The concentrate contained oligogalacturonides (with DP in the range of 2-18) and arabinooligosaccharides (with DP in the range of 2-8).

Pectin-derived oligosaccharides increase color and anthocyanin content in Flame Seedless grapes

Grapes grown in warm weather do not develop a desirable red color and require the use of products to enhance berry color. Pectin-derived oligosaccharides (PDOs) have been shown to have a role in various responses including plant defense, growth and development. In this work a mixture of PDOs with 3-20 degrees of polymerization was applied to Vitis vinifera cv. Flame Seedless grapes under field conditions and compared to the effects of ethephon (an ethylene-releasing compound). The effect of treatments on grape color, anthocyanin content and phenylalanine ammonia lyase (PAL) mRNA levels was evaluated. PDOs treatment increased berry color measured by the Color Index of Red Grapes (CIRG) and anthocyanin content, compared to ethephon and untreated berries (control); 1.5, 1 and 0.5 mg mL⁻¹ PDOs increased berry color by 30%, 27% and 26%, respectively, when compared to control berries. Levels of PAL mRNA accumulating in berries treated with PDOs were elevated within the first 24 h of treatment. PDOs enhanced the color and anthocyanin content of Flame Seedless grape berries possibly due by the induction of PAL mRNA expression. The results demonstrated that PDOs can be used to improve fruit quality aspects such as berry skin color.

Assessment of the Production of Oligomeric Compounds from Sugar Beet Pulp

In order to obtain pectin-derived oligosaccharides (mainly arabinooligosaccharides and oligogalacturonides), samples of sugar beet pulp (SBP) were subjected to hydrothermal processing under nonisothermal conditions. Experiments carried out to reach temperatures in the range 160−175 °C (corresponding to values of the severity factor R0 in the range 287−835 min) led to comparatively high concentrations of both oligogalacturonides and arabinooligosaccharides. When SBP was treated to achieve a maximum temperature of 160 °C (R0 = 287 min) or 163 °C (R0 = 357 min), the overall amount of oligomers present in the reaction liquors recovered by pressing accounted for 31.2 and 29.9 g/100 g of oven-dried SBP, respectively, with a limited amount of nonvolatile impurities (about 0.15 g/g of oven-dried matter) and a mass ratio of arabinooligosaccharides/oligogalacturonides of about 1:1. Spent solids were washed with water, and the washing liquors were assayed for oligomers. Recovery of washing liquors would increase the...