Valorization of pectins from coffee wastes for the development of pectin-chitosan films.

Coffee wastes are underused materials, largely available in coffee producing regions, which can be used to obtain pectins for the development of films for packaging. Coffee residual water (CRW) provided a phenolic and protein rich-pectic fraction (CRWP), which has 49 % uronic acid. This pectic fraction was used for the development of films with chitosan (Chit). Additionally, pectins extracted from coffee pulp with acid, Coffea arabica pectin (CAP), hot water-soluble pectic fraction (HWSP), and chelating agent-soluble pectic fraction (CSP), were used to develop pectin-chitosan films. Flow and viscoelastic properties of film forming solutions were assessed, showing better characteristics for the pectins from the pulp over those from the residual water. The different composition of the pectin fractions allowed to relate film properties with their structural features and Fourier transform infrared (FTIR) spectroscopy showed interactions between pectin and chitosan in the films. Results showed that CAP-Chit and CSP-Chit films were transparent, hydrophobic, and had the best mechanical properties. These results demonstrate that coffee residual wastes have the potential to provide pectins that can be used for the development of films.

Fractionation and characterization of cell wall polysaccharides from coffee (Coffea arabica L.) pulp.

Cell wall polysaccharides were isolated by sequential extractions from coffee pulp, the main solid waste from coffee processing. Extractions were conducted with distilled water at room and boiling temperatures, 0.5 % ammonium oxalate and 0.05 M Na2CO3 to obtain pectic fractions. Hemicelluloses were extracted by using 2 M and 4 M NaOH. The composition of the hemicellulose fractions suggested the presence of xyloglucans, galactomannans and arabinogalactan-proteins (AGPs). The main part of the cell wall polysaccharides recovered from coffee pulp were pectins branched with arabinogalactans. Coffee pulp pectic fractions were low-methoxylated with various amounts of protein (0.5-8.4 %) and phenolics (0.7-8.5 %). Detection at 280 nm in the HPSEC analyses and radial gel diffusion assay using Yariv reagent indicated the presence of AGPs in most of these fractions. NMR analyses of chelating agent (CSP) and dialyzed water (WSPD) extracted pectins were carried out. The results demonstrated that CSP contains only AG I. On the other hand, AG I and AG II are present in WSPD, probably covalently linked to the pectic portion. Comparison with the literature indicated similarities between the cell wall polysaccharides from coffee pulp and green coffee beans.

Schizophyllan from Schizophyllum commune BRM 060008: Potential application as an inhibitor of lipase.

ß-D-glucan has significant implications in regulating lipid metabolism and preventing diseases associated with lipid accumulation. Schizophyllan (SPG) from Schizophyllum commune fungus is a commercially important ß-glucan with applications in the health food industry, pharmacy, and cosmetics. However, SPG was obtained by submerged culture of the wood-rotting and filamentous fungus S. commune BRM 060008, which may have been isolated from the Cerrado Biome of Brazil. In this study, to confirm that the polysaccharide produced by BRM 060008 strain fermentation was indeed (1→3)(1→6)-ß-D-glucan, it was purified and characterized using Fourier transform infrared spectroscopy, thermogravimetric analysis, high-performance size exclusion chromatography, nuclear magnetic resonance, and methylation analysis. The polysaccharide produced was identified as the ß-D-glucan expected with a high molecular weight (1.093 × 106 g/mol) and the thermogravimetric analysis indicated a maximum degradation temperature of ~324 °C and a 60 % residual weight, lower than commercial SPG. The molecular structure and thermal properties of the ß-D-glucan were similar to the commercial sample. Additionally, the in vitro pancreatic lipase inhibitory activity was evaluated, investigating anti-obesity and anti-lipidemic properties. The results showed unprecedented lipase inhibition activity to SPG prepared using the S. commune strain BRM 060008, making it promising for food and pharmaceutical applications.

New findings on acid-extractable pectins from soy hull.

Soy hull has been considered a potential source of commercial pectin. The aim of the present study was to investigate its real potential as a source of pectin. Soy hull (sample 1) was extracted with 0.1 M HCl, for 45 min, at 90 °C (fraction A), conditions previously reported to result in yields and GalA in the range of commercial pectins. The extraction resulted in low uronic acid content (UA 39 %) and lower yield. Similar values were obtained using harsher conditions (boiling 0.14 M HNO3 for 30 min and 60 min - Fractions B and C, respectively). HSQC-NMR confirmed the coextraction of galactomannans. Considering the unexpected results, three other soy hull samples (2, 3 and 4) were used for extraction. The yields and UA were in the range of 10-13 % and 26-48 %, respectively, also below published data. Prior removal of galactomannan by water extraction increased the UA content to 62 % and gave rise to a pectin with a degree of methyl-esterification (DM) of 29 %. The pectin had remarkable amount of rhamnogalacturonan I and xylogalacturonan and did not form gel with calcium. The findings using four different commercial samples did not support previously published data and demonstrated that soy hull is not suitable as a raw material for production of food grade pectins by conventional extraction.

Extraction and characterization of a pectin from coffee (Coffea arabica L.) pulp with gelling properties.

About 0.5 ton of coffee pulp is generated for each ton of coffee cherry processed. In the present study, this waste was investigated as a source of pectin. Coffea arabica L. pulp was dried, treated with ethanol and the pectin extracted with 0.1 M HNO3 (14.6 % yield). Chromatographic, colorimetric and spectroscopic methods were used for pectin characterization. It had 79.5 % galacturonic acid, high methoxyl content (63.2 %), low levels of acetylation, protein and phenolics and Mw of 3.921 × 105 g/mol. The pectin from coffee pulp was able to form gels with high concentration of sucrose or xylitol and low pH. The effect of pH (1.5-3.0), concentrations of pectin (0.5-2.5 %), sucrose (55-65 %) and xylitol (55-60 %) on the viscoelastic properties was investigated. Gels prepared with xylitol diplayed similar viscoelastic behavior to the gels prepared with sucrose. The results demonstrated that coffee pulp is a potential source of commercial pectin with gelling properties.

Optimization of acid-extraction of pectic fraction from grape (Vitis vinifera cv. Chardonnay) pomace, a Winery Waste.

Chardonnay grape pomace was evaluated as a source of pectin. A central composite design was used in order to determine the effect of pH, extraction time (Et) and liquid: solid ratio (LS) on the yield and uronic acid (UA) content of the pectins extracted using boiling HNO3 solution. The optimized extraction condition to reach the maximum yield and UA was pH = 2.08, Et = 135.23 min and LS = 35.11 ml/g, resulting in theoretical yield of 12.8% and UA of 64.4%. The experimental yield of the pectic fraction obtained under the optimized conditions (GPOP) was 11.1% and the UA was 56.8%. GPOP had ~25% glucose. It was treated with α-amylase and amyloglucosidase, resulting in the fraction α-GPOP. The starch-free pectic fraction was composed of 63.5% UA, 7.8% rhamnose, 6.0% arabinose, 13.6% galactose and minor amounts of other neutral monosaccharides. It contained a low-methoxyl pectin (degree of methyl-esterification 18.1%) and had an average molar mass of 154,100 g/mol. It consisted of 55.7% homogalacturonan and 35.2% rhamnogalacturonan I (RG-I). NMR analyses suggest that RG-I portion of α-GPOP is highly branched by short chains or single residues of arabinose and galactose.

Pectin from Brassica oleracea var. italica triggers immunomodulating effects in vivo.

The immunomodulatory ability of pectins is related with structural features such as the degree of methyl-esterification and branching, as well as the molecular mass. The pectin FB, extracted from broccoli stalks (Brassica oleracea var. italica) had low molecular mass, 56% methyl-esterification and galactose as the main neutral sugar, sharing some characteristics with the modified citrus pectin (MCP), which has been extensively studied in vivo and in vitro due its immunomodulator potential. Considering that broccoli has an important role in the diet, the main objective of this study was to investigate the ability of FB in modulating the immune system in vivo. At concentrations 100-500 µg/mL, FB did not affect the viability of macrophages. Evaluations on morphology and phagocytic activity showed that FB (500 µg/mL) increased the number of activated macrophages by 39% and phagocytic activity by 30% within 48 h. FB (200 mg/kg) administered intraperitoneally increased the number of peritoneal macrophages in mice by 490% after 24 h and modulated these cells for an activated phenotype. In mice, oral administration of FB (200 mg/kg) stimulated lymphocytes from spleen and bone marrow proliferation. FB did not induce nitric oxide (NO) production by macrophages and also did not affect the levels of pro-inflammatory interleukins IL-1ß and IL-12 by peritoneal macrophages, but induced the production of the anti-inflammatory interleukin IL-10. The results could suggest that the anti-inflammatory effects triggered by FB could be related to its degree of esterification and pointed this polysaccharide as a target for the development of new immunomodulatory drugs.

Changes in the composition and structure of cell wall polysaccharides from Artemisia annua in response to salt stress.

Artemisia annua is cultivated mainly for isolation of artemisinin, a potent antimalarial compound. Moderate salt stress has been proved to increase the artemisinin synthesis by the plant. The aim of this study was to evaluate the influence of salt stress on physiological parameters and cell wall polysaccharides of A. annua. Plants subjected to salt stress displayed reduction in the biomass and length and showed high damage of cellular membranes. Cell wall polysaccharides extracted from aerial parts with hot water, EDTA and NaOH also exhibited modifications in the yield and monosaccharide composition. The main changes were found in the pectic polysaccharides: increase of homogalacturonan domain, increase of neutral side chains and increase in the methyl esterification. 1H NMR analyses of pectins indicated that for A. annua, arabinans have an important role in coping with salt stress. Hemicellulose domain was also modified under salt stress, with increased xylose contents. The results indicated adaptations in the cell wall of A. annua under salt stress.

Hypoxia protects against the cell death triggered by oxovanadium-galactomannan complexes in HepG2 cells.

BACKGROUND: Polysaccharides from various sources have been used in traditional medicine for centuries. The beneficial pharmacological effects of plant-derived polysaccharides include anti-tumor activity. METHODS: Here, we evaluated the anti-cancer effect of the MSAGM:VO complex under hypoxic conditions (1% oxygen). MSAGM:VO is a complex of the hydrolysate of galactomannan (MSAGM) from Schizolobium amazonicum with oxovanadium (IV/V). The hepatocellular carcinoma (HCC) cell line HepG2 was selected as HCC are one of the most hypoxic solid tumors. RESULTS: Our results showed that the strong apoptotic activity of MSAGM:VO observed in HepG2 cells under normoxic conditions was completely lost under hypoxic conditions. We found a dynamic balance between the pro- and anti-apoptotic members of the Bcl-2 protein family. The expressions of anti-apoptotic Mcl-1 and Bcl-XL increased in hypoxia, whereas the expression of pro-apoptotic Bax decreased. MSAGM:VO strongly induced autophagy, which was previously characterized as a pro-survival mechanism in hypoxia. These results demonstrate total elimination of the anti-cancer activity of MSAGM:VO with activation of autophagy under conditions of hypoxia. CONCLUSION: Although this study is a proof-of-concept of the impact of hypoxia on the potential of polysaccharides, further study is encouraged. The anti-tumor activity of polysaccharides could be achieved in normoxia or through raising the activity of the immune system. In addition, combination strategies for therapy with anti-autophagic drugs could be proposed.

Pectins from the pulp of gabiroba (Campomanesia xanthocarpa Berg): Structural characterization and rheological behavior.

The pulp of gabiroba fruits was submitted to a hot water extraction, giving rise to a crude pectin named GW. GW was shown to be composed mainly of arabinose (54.5%), galacturonic acid (33.5%), galactose (7.6%), and rhamnose (1.6%). GW was characterized by chromatographic and spectroscopic methods indicating the presence of homogalacturonans (HG) with a degree of methyl-esterification (DM) of 60% and rhamnogalacturonans I (RG-I). HG domain represents 31.9% and RG-I domain 65.3%. Furthermore, GW was submitted to sequential fractionation methods, giving rise to GWP-TEP fraction, structurally characterized by the predominance of HG regions, and confirmed by NMR analysis. The rheological behavior of GW was analyzed at 1%, 3%, and 5% (w/v) concentration with 0.1 mol L-1 NaCl. All samples showed shear thinning behavior. In the oscillatory measurements, the 1% GW showed a liquid-like behavior, while the 3% presented a concentrated solution behavior and the 5% GW a gel behavior.

Investigation of cell wall polysaccharides from flour made with waste peel from unripe banana (Musa sapientum) biomass.

BACKGROUND: The peel from unripe banana biomass is an agroindustrial waste. The present study aimed: (i) to extract pectin from enzymatically-treated waste peel from unripe banana biomass (WPUBB) using a Box-Behnken design to optimize the extraction conditions (temperature, pH and extraction time) and obtain a maximum yield and (ii) to fractionate the polysaccharides from WPUBB employing sequential extractions using different solvents. RESULTS: The optimized product was obtained at 86 °C, pH 2.00, for 6 h and it presented a yield of 11.63%. The optimized product had low galacturonic acid content and a high amount of glucose (82.3%), suggesting the presence of starch (as confirmed by the bi-dimensional heteronuclear single quantum coherence NMR spectrum). All of the fractionated polysaccharides had a high glucose content. Low amounts of pectin were found in the water, chelating and diluted alkali-soluble fractions. The fractions extracted using NaOH indicated the presence of glucuronoarabinoxylans. CONCLUSION: Glucose was the main monosaccharide found in all the fractions extracted from the WPUBB. Although the present study suggests that WPUBB is still not suitable for pectin extraction using current technologies, other compounds, such as resistant starch and glucuronoarabinoxylans, were found, suggesting that WPUBB could be used in the development of food formulations. © 2019 Society of Chemical Industry.

Cytotoxicity of xyloglucan from Copaifera langsdorffii and its complex with oxovanadium (IV/V) on B16F10 cells.

The aim of this study was to investigate the effects of xyloglucan extracted from Copaifera langsdorffii seeds (XGC) and its complex with oxovanadium (XGC:VO) in murine melanoma B16F10 cells. The formation of complexes was followed by potentiometric titration and further demonstrated by 51V RMN. The viability and proliferation of B16F10 cells were reduced up 50% by the xyloglucan and its complex, both at 200 µg/mL, from 24 to 72 h. Cytotoxic effects of XGC and XGC:VO do not involve changes in cell cycle progression. Only XGC:VO (200 µg/mL) promoted the cell death evidenced by annexin V stain. XGC increased the respiration and lactate levels in melanoma cells, while XGC:VO reduced about 50% the respiration and levels of pyruvate, without alter the lactate levels, indicating that both xyloglucan preparations interfere with the metabolism of B16F10 cells. No change in activity of the enzyme hexokinase and expression of pyruvate kinase M2 was observed. XGC:VO (200 µg/mL) negatively modulated the expression of the ß subunit of ATP synthase. The results demonstrate that the cytotoxicity of XGC and XGC:VO on murine melanoma B16F10 cells can be related to the impairment of the mitochondrial functions linked to energy provision.

Characterization of cell wall polysaccharides from Sicana odorifera fruit and structural analysis of a galactan-rich fraction pectins as side chains.

Sicana odorifera is a Brazilian native fruit. In this work, cell wall polysaccharides from S. odorifera pulp were isolated by sequential extraction with water, citric acid, and sodium hydroxide solutions. The monosaccharide composition of crude polysaccharide fractions was determined. The aqueous fractions displayed the highest yields and they were constituted by pectins, having mainly galactans as side chains. The citric acid fraction (SCA) had galactose as the main component. The hemicellulosic fractions consisted mainly of xylose, mannose, galactose, and glucose, suggesting the presence of xyloglucans, xylans and mannans. The SCA fraction was further purified, resulting in a linear galactan (SCAI2). NMR and methylation analysis showed that SCAI2 was a ß-(1→4) d-galactan with molar mass of 17,560 g/mol, determined by light scattering. The presence of a linear galactan in free form in fruits is unusual because these polymers usually occur as side chains of type I rhamnogalacturonans.

Pulp and Jam of Gabiroba (Campomanesia xanthocarpa Berg): Characterization and Rheological Properties.

This study evaluated the physicochemical characterization and rheological behavior of gabiroba pulp, and a gabiroba jam formulation. Gabiroba pulp presented a heterogeneous ultrastructure with a denser area formed by a compact mesh and a porous interface containing fibers. The fibers' presence promoted a slip effect when the gabiroba pulp was subjected to shear. Gabiroba pulp showed a gel behavior with thermal stability. Gabiroba jam, developed using pulp as the raw material, had shear thinning behavior exhibiting yield stress described by the Herschel-Bulkley model. The dynamic oscillatory analysis showed that gabiroba jam typically behaved like a gel, i.e., G' values higher than the G″ in all frequency ranges evaluated. The results showed that gabiroba pulp is suitable for use as a raw material in the development of food products such as jam, encouraging the preservation of this native Brazilian species.

Cell wall polysaccharides from Ponkan mandarin (Citrus reticulata Blanco cv. Ponkan) peel.

Cell wall polysaccharides from ponkan peel were investigated with the aim of gain knowledge about their potential for different applications and the use of ponkan peel as raw material for pectin extraction. The plant material was defatted using MeOH:CHCl3, pretreated with DMSO and then subjected to sequential extractions with cold and hot water, ammonium oxalate, HCl, Na2CO3, 2 M and 4 M NaOH in order to obtain polysaccharides. The polysaccharide fractions were analyzed by chemical, chromatographic and spectroscopic methods Cold and hot water-soluble pectins contained higher amounts of GalA and higher degrees of methyl-esterification (DM) than ammonium oxalate and HCl fractions. Na2CO3 extraction provided non-esterified arabinose-rich pectins which formed gel in a dialysis step. NaOH solubilized hemicelluloses, composed mainly of xyloglucans, galactomannans and galactoglucomannans. The water-soluble fraction (WSP) was purified using α-amylase and amyloglucosidase and gave rise to the subfraction named α-WSP. The α-WSP was a pectin composed of HG and RG-I domains containing side chains of arabinans and short-chains of galactans, with low DM (39.4%) and Mw of 1.615 × 105 g/mol.

Extraction of pectin from ponkan (Citrus reticulata Blanco cv. Ponkan) peel: Optimization and structural characterization.

A central composite experimental design was used to evaluate the influence of pH, extraction time and liquid:solid ratio on the yield and uronic acid content of the pectin from ponkan peel. The response surface methodology showed that the yield is positively influenced by lower pHs, longer extraction times and higher liquid:solid ratio, whereas the uronic acid content decreases with increasing extraction time. The conditions that resulted in the highest yield and highest uronic acid content were defined as pH 1.6, extraction time of 100 min and liquid:solid ratio of 36 mL/g. The pectin obtained under these conditions (PPOP) had an experimental yield of 25.6%, below the predicted theoretical value despite the good fit of the model (R2 = 0.96) and the galacturonic acid content was 84.5%, in close agreement with the predicted theoretical value. PPOP was composed mainly of a homogalacturonan with degree of methyl esterification of 85.7% and a rhamnogalacturonan I region mainly branched by galactans. In addition, PPOP had a very low degree of acetylation (0.1%) and average molar mass of 80,650 g/mol, determined by light scattering. The results showed that ponkan peel may be used as a source of citrus pectin in the regions where this species is cultivated.

Characterization and physicochemical properties of pectins extracted from agroindustrial by-products.

The composition and fine structure of pectins found in plant cell walls are heterogeneous, with striking differences, depending on their source, and this eventually determines their functional and technological properties. The aim of this study was to extract and determine the chemical composition and physicochemical properties of pectins from different sources: passion fruit peel, orange pomace, and soy hull. Pectin extraction was performed with heated hydrochloric acid solution, followed by precipitation with 96% ethanol. Extraction yield, chemical composition, molar mass, physicochemical properties (fat absorption capacity, cation exchange capacity, water holding capacity, and antioxidant activity) of pectin were measured. Pectin extraction efficiency was higher for passion fruit peel and orange pomace (15.71 and 17.96%, respectively). Soy hull had low pectin extraction (5.66%). Galacturonic acid content was 23.21% for passion fruit peel pectin and 16.01% for orange pomace pectin. Water holding capacity, fat absorption capacity, and cation-binding capacity present in pectin extracted from passion fruit peel were higher, suggesting this poorly investigated product could be used as thickening and emulsifying agents in food preparations. Phenolic compounds with antioxidant capacity provide pectins with additional properties and expand their industrial use.

Toxicity of native and oxovanadium (IV/V) galactomannan complexes on HepG2 cells is related to impairment of mitochondrial functions.

Polysaccharides and vanadium compounds have been studied due to their antitumor potential. In this study, the cytotoxic effects of galactomannan preparations on HepG2 cells were investigated. Native galactomannan from S. amazonicum (SAGM) and its modified form (MSAGM) were complexed with oxovanadium resulting in SAGM:VO and MSAGM:VO, respectively. The complexation was confirmed by NMR, FTIR, and AAS. SAGM and MSAGM:VO (250µg/mL) after 72h decreased viability by 51% and 58%, respectively, while the inhibition of the HepG2 cell proliferation was of ∼27% and ∼46%, respectively. SAGM and MSAGM:VO (250µg/mL) significantly inhibited all states of respiration (basal: 85% and 63%; uncoupled: 90% and 70%; and leak: 30% and 58%) after 72h. ROS levels increased by ∼149% after the treatment with MSAGM:VO (250µg/mL) for 72h, while ΔΨm decreased by ∼50%. Our results indicate that galactomannan preparations from S. amazonicum, especially SAGM and the MSAGM:VO complex, could be considered as potential antitumor drugs for further investigations, once they have the ability to make HepG2 cells susceptible to death by affecting vital cellular processes such as respiration and ROS generation.

Degalactosylation of xyloglucans modify their pro-inflammatory properties on murine peritoneal macrophages.

Considering the potential applications of partially degalactosylated xyloglucans as a drug delivery vehicle and reconstruction of tissues, the aim of this study was to investigate whether degalactosylated xyloglucans are immunologically active. The effects of the degalactosylated xyloglucan from seeds of Copaifera langsdorffii (XGCd), Hymenaea courbaril (XGJd), and Tamarindus indica (XGTd) on murine peritoneal macrophages in vitro were evaluated. XGCd, XGJd, and XGTd stimulated NO production in a dose-dependent manner reaching ∼280% for XGTd at 50µg/mL. Regarding cytokines production, XGJd at 50µg/mL increased IL-1ß level by ∼100% and XGCd (10µg/mL) enhanced IL-6 level by 40%. At 10µg/mL, XGTd increased TNF- α and IL-1ß levels by 104 and 2370%, respectively, as compared to the control group. For IL-6, XGTd enhanced this cytokine production by 80% at all concentrations tested. XGTd exhibited the most intensive effects on the production of pro-inflammatory mediators by peritoneal macrophages. All degalactosylated xyloglucans evaluated showed not to be biologically inert. Thus, this finding is relevant for groups that are investigating the use of degalactosylated xyloglucan from T. indica for drug delivery and reconstruction of tissues. The effects observed could contribute to potentiate the immune system against infections or toxicity to tumor cells.

Galactomannan from Schizolobium amazonicum seed and its sulfated derivatives impair metabolism in HepG2 cells.

This study evaluated the effects of native galactomannan from Schizolobium amazonicum seeds and its sulfated forms on certain metabolic parameters of HepG2 cells. Aqueous extraction from S. amazonicum seeds furnished galactomannan with 3.2:1 Man:Gal ratio (SAGM) and molar mass of 4.34×105g/mol. The SAGM fraction was subjected to sulfation using chlorosulfonic acid to obtain SAGMS1 and SAGMS2 with DS of 0.4 and 0.6, respectively. Cytotoxicity of SAGM, SAGMS1, and SAGMS2 was evaluated in human hepatocellular carcinoma cells (HepG2). After 72h, SAGM decreased the viability of HepG2 cells by 50% at 250µg/mL, while SAGMS1 reduced it by 30% at the same concentration. SAGM, SAGMS1, and SAGMS2 promoted a reduction in oxygen consumption and an increase in lactate production in non-permeabilized HepG2 cells after 72h of treatment. These results suggest that SAGM, SAGMS1, and SAGMS2 could be recognized by HepG2 cells and might trigger alterations that impair its survival. These effects could be implicated in the modification of the oxidative phosphorylation process in HepG2 cells and activation of the glycolytic pathway.