Antioxidant pectins from eggplant (Solanum melongena) fruit exocarp, calyx and flesh isolated through high-power ultrasound and sodium carbonate.

Dried and milled eggplant fruit peel and calyces (PC) and mesocarp, placenta and core (Mes) were utilized as natural sources of valuable chemicals. Pectins were extracted with 0.1 M Na2CO3 (1 h; 23 °C). A high-power ultrasound (US) pretreatment (10 min net time; 12.76 W/cm2 power intensity) in 10:200 (g/mL) powder:water ratio led to the lowest solvent and energy consumptions after the subsequent 0.1 M Na2CO3 stirring, permitting the highest recoveries of uronic acid (UA) from PC and Mes (80.25 and 93.8 %, respectively). Homogalacturonans (>65 % w/w UA) of low degree of methylesterification, of acetylation, and 90,214-138,184 Da molecular weights with low polydispersity (≈1.32-1.40) were obtained. They included released ferulate (≈3.5 mg/100 g) esterified pectins. Antioxidants (caffeoylquinic acid, putrescine and spermidine derivatives, ß-carotene, lutein) gave additional technological value to their thickening effect as pectins protected tryptophan, tyrosine, alkyl side chains and sulfhydryl of skim milk proteins from UV-C photo-oxidation.

Genotoxic risk in humans and acute toxicity in rats of a novel oral high-dose coenzyme Q10 oleogel.

Coenzyme Q10 (CoQ10) supplementation has demonstrated to be safe and effective in primary and secondary CoQ10 deficiencies. Previously, we have designed a high-dose CoQ10 oleogel (1 g/disk) with excipients used in quantities that do not represent any toxic risk. However, it was necessary to demonstrate their safety in the final formulation. Following this purpose, an acute toxicity study of the oleogel in rats was performed. Furthermore, the genotoxic risk was evaluated in human volunteers after CoQ10 supplementation with oleogel and compared to the solid form (1 g/three 00-size-capsules). In addition, the general health status and possible biochemical changes of the participants were determined using serum parameters. Results suggested the absence of adverse effects caused by the interaction of the components in the oleogel formulation. Therefore, we conclude that the designed novel high-dose CoQ10 oleogel was safe for oral consumption.

Perennial halophyte Salicornia neei Lag.: Cell wall composition and functional properties of its biopolymers.

Salicornia neei halophyte extends in Argentina seashores. To envisage potential applications, cell wall sequential extraction performed on dry plant yielded 1.1, 2.4, 0.3 and 0.9% of pectin fractions respectively extracted by room temperature water, 90 °C-water, CDTA and Na2CO3. They contained 21-33% uronic acids (UA) with low degree of methylation and 0.5-1.2 M ratios of neutral sugars to UA. High arabinose level suggests that long arabinan side-chains maintain cell wall flexibility in water deficit. Fractions also contained 10-36% of proteins. The KOH-soluble fractions (4.3%) were mainly arabinoxylans. At 2.0% w/v, pectin fractions developed "weak gel"-type networks with Ca2+, while arabinoxylans generated "dilute solutions". Cellulose (28%) and lignin (45.1%) were the main biopolymers in the final residue, which showed low water swelling capacity (3.6 mL/g) due to lignin, increasing when arabinoxylans were also present. Phenolics (9.8%) were mainly water-extractable. Salicornia is a source of biopolymers and antioxidants potentially useful for food applications.

Bioavailability of coenzyme Q10 loaded in an oleogel formulation for oral therapy: Comparison with a commercial-grade solid formulation.

Coenzyme Q10 (CoQ10) is essential in mitochondrial bioenergetics and is a potent endogenous antioxidant. Low CoQ10 levels are associated with neurodegenerative, metabolic, muscular and cardiovascular disorders. Early treatment with high doses (5-50 mg/kg/day) demonstrated to limit the onset and progression of neuropathology. Recently, we developed an oleogel matrix able to support a high dose of oil-dissolved CoQ10, easy to swallow by CoQ10-deficient patients who suffer from secondary dysphagia. In the present study, we evaluated the bioavailability of oleogel-dissolved CoQ10 and plasma antioxidant status in healthy adults in single-dose and repeated-dose studies. The single-dose study demonstrated that, in terms of CoQ10 bioavailability, 1 g CoQ10/5g oleogel-disk was equivalent to the solid form (1 g CoQ10/three 00-size-capsules), whereas the repeated-dose study (14-days-administration) demonstrated a significantly higher increase in plasma CoQ10 when administered through the oleogel, which could be compatible with the levels necessary to achieve an adequate therapeutic response. Also, a trend to a higher plasma apparent half-life (greater than24 h) was observed for the oleogel-loaded-CoQ10. In conclusion, the oleogel matrix does not compromise the oil-dissolved CoQ10 bioavailability and can prevent the non-adherence to this vital supplementation in patients with high CoQ10 requirements. No significant variation in the plasma antioxidant status (vitamins A, E and C, glutathione and TBARs) was observed.

Antioxidant pectin enriched fractions obtained from discarded carrots (Daucus carota L.) by ultrasound-enzyme assisted extraction.

Carrot residues were upgraded as pectin-enriched fractions (PEFs) useful for functional food formulation due to co-extracted antioxidants (α- and ß-carotenes, lutein, α-tocopherol), and gelling effect. High power ultrasound (US)-enzyme assisted extraction was applied for efficiency and sustainability. Carrot powder (CP) in citrate-buffer (pH 5.20) was submitted to US-pretreatment (12.27 W/cm2: 20 kHz, 80% amplitude, 20 min) and a subsequent digestion (5 h-40 °C) without or with hemicellulase or cellulase. US-hemicellulase led to the highest PEF yield (27.1%), and extracted almost the whole pectin content of CP. US-pretreatment increased the extraction yield of all PEFs, but the existence of an additional positive effect of the following step depended on the enzyme used. PEFs contained 40-47% of UA with low DM (24-49.9%), and co-extracted antioxidants. US decreased the antioxidant contents, DM, and molecular weight, but allowed obtaining calcium crosslinked true gels, also with higher elastic modulus than non-US-extracted PEFs, being promising as food additives.

High-dose coenzyme Q10-loaded oleogels for oral therapeutic supplementation.

Coenzyme Q10 (CoQ10) is a mitochondrial respiratory cofactor and potent endogenous antioxidant. In CoQ10-deficient patients, early treatment with high-oral doses (5-50 mg/kg/day) can limit the progression of renal disease and the onset of neurological manifestations. Crystalline CoQ10 is lipophilic, water-insoluble, and poorly absorbed in the gut. Here, CoQ10 showed low bulk density, another important disadvantage in solid oral formulations. Thus, we propose the use of oleogels to maintain dissolved a high-dose of CoQ10 in medium-chain triglyceride (MCT) oil, using ethylcellulose (EC) for gelling, and a surfactant (sorbitan monostearate -SMS- or lecithin). "True gels" were only obtained with the surfactant presence. Thermoreversible oleogels with 1 g of dissolved CoQ10 per 5 g-disk were successfully developed with proved stability and solubility for 12 months (25.0 °C). SMS was better than lecithin as a surfactant because it allowed lower syneresis, higher CoQ10 retention for 12 months, and notably higher oxidative-stability of the MCT-oil, best immobilized by its true gel network. Plastic deformation without fracture was determined under compression, emulating the soft deformation behavior inside the mouth. SMS-oleogels allowed loading a maximal solubilized CoQ10 dose with maximal stability, and may be easier to swallow by CoQ10-deficient patients who suffer from secondary dysphagia.

Pectin-based composite film: Effect of corn husk fiber concentration on their properties.

Considering the polysaccharide composition and 32% of crystallinity of the water insoluble fiber extracted from corn husk (CHF) agricultural residue, its filler performance as water vapor permeability (WVP) and mechanical modifier in edible films based on commercial low methoxyl pectin (LMP) was evaluated (0, 1, 3, 5, 8% concentrations). The 53-µm-CHF carried phenolics and carotenes, and composites showed antioxidant capacity. Homogeneous films with a continuous LMP matrix were obtained. The 5%-CHF composite showed the highest surface contact angle (44°) and tensile strength, without change in elongation, while WVP was decreased in the 3-8% CHF-LMP-films. The latter was ascribed to the CHF-filler crystallinity whereas the improvement in mechanical performance and contact angle was attributed to a CHF-interconnected network formed at 5%-CHF critical concentration. Corn husk residue can be utilized as a source of fibers for material development. Composites with enhanced performance can be an antioxidant strategy at food interfaces.

Carrot fiber (CF) composite films for antioxidant preservation: Particle size effect.

The effect of particle size (53, 105 and 210 µm) of carrot fiber (CF) on their hydration properties and antioxidant capacity as well as on the performance of the CF-composite films developed with commercial low methoxyl pectin (LMP) was studied. It was determined that CF contained carotenoids and phenolics co-extracted with polysaccharides (80%), rich in pectins (15%). CF showed antioxidant activity and produced homogeneous calcium-LMP-based composites. The 53-µm-CF showed the lowest hydration capability and produced the least elastic and deformable composite film due probably to CF bridged by calcium-crosslinked LMP chains. Antioxidant activity associated to the loaded CF was found in composites. When L-(+)-ascorbic acid (AA) was also loaded, its hydrolytic stability increased with the decrease in CF-particle size, showing the lowest stability in the 0%-CF- and 210 µm-CF-LMP films. Below ≈ 250 µm, the particle size determined the hydration properties of pectin-containing CF, affecting the microstructure and water mobility in composites.

Protease and hemicellulase assisted extraction of dietary fiber from wastes of Cynara cardunculus.

The action of protease and hemicellulase for the extraction of fractions enriched in soluble fiber from bracts and stems of Cynara cardunculus was evaluated. Using a two-factor simplex design comprising protease amounts of 0-200 µL and hemicellulase amounts of 0-200 mg for 5 g of material, we explored the effect of a 5 h enzymatic treatment at 40 °C on the chemical composition and yield of the fractions isolated. The fractions contained inulin and pectin. In general, the protein, inulin, and polyphenol contents and also the yields were higher for fractions obtained from stems. The most marked effects were observed when enzymes were used at higher concentrations, especially for hemicellulase. The inclusion of a pre-heating step increased the yield and the inulin content for fractions isolated from bracts and stems and decreased the protein and polyphenol contents, and the galacturonic acid for bracts. These fractions, in general, contained the polyphenolic compounds monocaffeoylquinic acid, apigenin, and pinoresinol.

Upgrading of residues of bracts, stems and hearts of Cynara cardunculus L. var. scolymus to functional fractions enriched in soluble fiber.

Since only the central portion of the immature flowers of artichoke (Cynara cardunculus L. var. scolymus) is consumed (<20%) it is interesting to upgrade its residues to render value added products. In this research, bracts (B), hearts (H) or stems (S) were used to isolate fractions enriched in soluble fiber. Extraction was performed in citrate buffer with or without hemicellulase. Additionally, the effect of preheating (70 °C - 5 min) prior to extraction was also tested. Polysaccharides were precipitated with ethanol and the fractions obtained were freeze-dried. The presence of the enzyme increased fiber yields and preheating produced an additional increment, especially from stems (≈21%). Isolated fibers were constituted by 70-84% of carbohydrates and 2-25% of proteins, and contained phenolics (2.1-8.2 g/100 g). Carbohydrates included uronic acids (12-25%) and neutral sugars (NS, 4-55%) of pectins, and inulin (13-55%). The lowest protein and NS contents and the highest inulin content were obtained with the enzyme and preheating. The behavior of fractions isolated with higher yields was characterized, observing a pseudoplastic behavior in water and gelation with Ca(2+). They also showed antioxidant activity and an inhibitory effect against herpes simplex virus type 1 without cytotoxicity. The isolated fractions retaining bioactive compounds can be useful as functional food ingredients.

Chemical and functional properties of cell wall polymers from two cherry varieties at two developmental stages.

The cell wall polysaccharides of Regina and Sunburst cherry varieties at two developmental stages were extracted sequentially, and their changes in monosaccharide composition and functional properties were studied. The loosely-attached pectins presented a lower d-galacturonic acid/rhamnose ratio than ionically-bound pectins, as well as lower thickening effects of their respective 2% aqueous solution: the lowest Newtonian viscosity and shear rate dependence during the pseudoplastic phase. The main constituents of the cell wall matrix were covalently bound pectins (probably through diferulate cross-linkings), with long arabinan side chains at the RG-I cores. This pectin domain was also anchored into the XG-cellulose elastic network. Ripening occurred with a decrease in the proportion of HGs, water extractable GGM and xylogalacturonan, and with a concomitant increase in neutral sugars. Ripening was also associated with higher viscosities and thickening effects, and to larger distribution of molecular weights. The highest firmness and compactness of Regina cherry may be associated with its higher proportion of calcium-bound HGs localized in the middle lamellae of cell walls, as well as to some higher molar proportion of NS (Rha and Ara) in covalently bound pectins. These pectins showed significantly better hydration properties than hemicellulose and cellulose network. Chemical composition and functional properties of cell wall polymers were dependent on cherry variety and ripening stage, and helped explain the contrasting firmness of Regina and Sunburst varieties.

Hydrolytic and oxidative stability of L-(+)-ascorbic acid supported in pectin films: influence of the macromolecular structure and calcium presence.

The hydrolytic and oxidative stability of L-(+)-ascorbic acid (AA) into plasticized pectin films were separately studied in view of preserving vitamin C activity and/or to achieve localized antioxidant activity at pharmaceutical and food interfaces. Films were made with each one of the enzymatically tailored pectins (50%, 70%, and 80% DM; Cameron et al. Carbohydr. Polym.2008, 71, 287-299) or commercial high methoxyl pectin (HMP; 72% DM). Since AA stability was dependent on water availability in the network, pectin nanostructure affected the AA kinetics. Higher AA retention and lower browning rates were achieved in HMP films, and calcium presence in them stabilized AA because of higher water immobilization. Air storage did not change AA decay and browning rates in HMP films, but they significantly increased in Ca-HMP films. It was concluded that the ability of the polymeric network to immobilize water seems to be the main factor to consider in order to succeed in retaining AA into film materials.

Effect of extraction time and temperature on the characteristics of loosely bound pectins from Japanese plum.

The cell wall composition of Japanese plums (Prunus salicina) at six developmental stages was previously evaluated (Ponce et al., J. Agric. Food Chem. 2010, 58, 2562-2570). This fruit is an interesting source of pectins, polysaccharides of valuable functionality for pharmaceutical and food formulations. In the present work it was investigated how the different conditions for the aqueous extraction of pectins from Japanese plums affect the yield as well as their chemical and rheological characteristics. It has been determined that extraction with water at room temperature for periods longer than 2h did not produce additional increment of yield (12%) but decreased the average molecular weights of the extracted pectins. Pectins with a degree of methylation ≈40% with high viscosity in water and with adequate molecular weights (≈72,000) were obtained. Conversely, utilization of boiling water for extraction increased considerably the yields (33-38%) but the extracted pectins showed significant lower viscosity in water in spite of their higher molecular weights. The poorer thickening ability was associated to the lower proportion of arabinose residues present in the hairy regions of the pectin macromolecules extracted by hot water, which led the polymers to interact more transiently in a 2% w/v water solution.

Characterization of acid-extracted pectin-enriched products obtained from red beet (Beta vulgaris L. var. conditiva) and butternut (Cucurbita moschata Duch ex Poiret).

Chemical and rheological characteristics of fractions enriched in soluble dietary fiber are reported. These fractions were obtained through acid hydrolysis of butternut (Cucurbita moschata Duch ex Poiret) and red beet (Beta vulgaris L. var. conditiva) cell wall enriched powders. Hydrolysis was performed using citric acid at different pH values and reaction times (2 and 3 h). Yields obtained for butternut fractions were between 21 and 28 g/100 g; for red beet, yields were 24 and 31 g/100 g for pH 1.5 and 11 and 17 g/100 g for pH 2.0 for previously mentioned times; in general, the increase of the yield was directly correlated with the decrease of pH and the increase of reaction time. Products enriched in low methoxyl pectins were obtained in all cases. At the lowest pH assayed, pectins were essentially constituted by homogalacturonan; a significant content of neutral sugars was determined at the higher extraction pH. Neutral sugars were constituted mainly by arabinose, galactose, rhamnose, and glucose in different proportions for each fraction; in general, butternut fractions showed high glucose contents. Flow behavior for 2.00% (w/v) aqueous systems of the different products was evaluated. Data obtained for fractions isolated at pH 1.5 fit to Herschel-Bulkley and Cross models while those isolated at pH 2.0 fit to Ostwald and Cross models. All samples showed low viscosity and, hence, poor thickening properties.

Development of a high methoxyl pectin edible film for retention of l-(+)-ascorbic acid.

An edible film to carry l-(+)-ascorbic acid (AA) was formulated for natural antioxidant food protection. Considering previous works where films based on the "rigid" structure of gellan (deacylated) or on a mixture of acylated-deacylated (more "disordered") gellan were used for network development, pectin was herein chosen by considering that the alternating presence of "disordered" (hairy) regions together with ordered (homogalacturonan) ones could sufficiently immobilize water for better AA retention and lower browning. High methoxyl pectin (HMP) was first investigated. AA stability and browning were studied during film storage at 33.3, 57.7, or 75.2% relative humidity (RH) and 25 degrees C; their dependence on water mobility determined through (1)H NMR analysis as well as the correlation between browning and AA degradation were again found. Network characteristics and glycerol (plasticizer) interactions were analyzed through X-ray diffraction and Fourier transform infrared spectroscopy as well as through uniaxial tensile assay. From all results obtained, it was hypothesized that browning development in solidlike systems may be directly related to the water molecules more closely adsorbed on the hydroxyl-polymeric (active) surfaces. The HMP film microstructure produced the best immobilization of water molecules except at 75.2% RH, where it showed lower AA stability than acylated-deacylated gellan film. It is suggested that disordered regions of this pectin network may not be adequately counterbalanced by more transient junction zones of alternating hydrophilic (water) and hydrophobic (methyl ester) interactions, also disturbed by glycerol molecules, for accomplishing enough water immobilization in the whole network at 75.2% RH.