Increasing Pectin Content Research Articles

Aeration Increases Cadmium (Cd) Retention by Enhancing Iron Plaque Formation and Regulating Pectin Synthesis in the Roots of Rice (Oryza sativa) Seedlings

BackgroundAeration and water management increasing rhizosphere oxygen amount significantly promote rice (Oryza sativa) growth and yield, but the effect of root aeration on cadmium (Cd) toxicity and accumulation in rice seedlings under hydroponic culture remains unclear.ResultsResults showed that aeration promoted rice seedling growth and alleviated Cd toxicity. Transverse section discovered that Cd accelerated root mature and senescence while aeration delayed the mature and senescence of roots. Non-invasive Micro-test Technology (NMT) showed that aeration increased net O2 and Cd2+ influxes on the surface of roots while decreased net Cd2+ influx in xylem. Perls blue staining showed that aeration and Cd treatments increased iron plaque formation on the surface of roots. Results of metal concentration analysis showed that besides increasing Cd retention in iron plaque, aeration also increasing Cd retention in the cell wall of rice roots. Cell wall component analysis showed that aeration not only increased pectin content but also decreased pectin methylesterification degree (PMD) by increasing pectin methylesterase (PME) activity.ConclusionsAll of these results indicate that aeration not only delays root mature and senescence but also increases Cd retention in roots by enhancing iron plaque formation and regulating pectin synthesis in the roots of rice seedlings.

Okra pectin as lecithin substitute in chocolate

The effect of okra (Abelmoschus spp.) pectin as an emulsifier on the yield, textural properties, sensory and consumer acceptability of different chocolate formulations was investigated. Pectin was isolated from okra pods and incorporated into milk chocolate as lecithin substitute (emulsifier) at different levels (10–100%). Texture profile analysis and sensory evaluation (5-point hedonic scale) was performed on the different chocolate formulations. It was found that with increasing pectin content viscosity of the mixed system increased during milling and conching, which resulted in slower flow rate during draining from the ball mill and decreased yield. Substitution at 25:0 (%) (pectin: lecithin) yielded 84 bars of 9 g of chocolate per 1500 g of formulation after draining for 30 min compared to formulations containing lecithin. Chocolate samples 25:75 (%) (pectin:lecithin) had the highest overall acceptability (4.37 ± 0.30) which was not significantly different (p> 0.05) from sample 25:0 with overall acceptability of 4.23 ± 0.30. All the chocolate samples from the various formulations studied had similar sensory properties as well as textural parameters (hardness, cohesiveness, adhesiveness, springiness and chewiness). The present findings suggest that it is possible to use okra pectin as emulsifier to produce milk chocolate which is acceptable to consumers.

Sodium Hydrosulfide Mitigates Cadmium Toxicity by Promoting Cadmium Retention and Inhibiting Its Translocation from Roots to Shoots in Brassica napus.

The association between hydrogen sulfide (H2S) and cell wall composition with regard to the mitigation of cadmium (Cd) toxicity in Brassica napus L. was investigated. Cd caused growth retardation, leaf chlorosis, and decreased endogenous H2S content in Brassica napus roots. Stimulating l-cysteine desulfhydrase (LCD)-mediated H2S production with H2S releaser (NaHS) markedly improved plant growth, reduced Cd content in stems and leaves, and rescued Cd-induced chlorosis. Furthermore, increased Cd retention was observed in root cell walls, indicating that NaHS reduced Cd movement from the roots to upper-plant parts. Exogenous NaHS also significantly increased the content of pectin and the activity of pectin methylesterase in cell walls of roots, thereby increasing Cd retention in pectin fractions. However, intensification of H2S barely affected hemicellulose content under Cd stress. Intensified H2S signal, therefore, alleviates Cd toxicity in Brassica napus by increasing pectin content and its demethylation, increasing Cd fixation in cell walls, and reducing root-to-shoot Cd translocation.

Self-cross-linked melamine-formaldehyde-pectin aerogel with excellent water resistance and flame retardancy

Self-cross-linked aerogel based on pectin and melamine-formaldehyde resin (MF) was fabricated via freeze-drying method using water as solvent, where pectin is structural material meanwhile acting as acid to catalyse the cross-linking of MF. The cross-linking reaction easily occurs without additional additives, which can be significantly accelerated at elevated temperatures, with a critical value of about 55 °C. The obtained aerogel shows network microstructures as observed with SEM. With increasing pectin content, the aerogel shows significantly increased compressive modulus. The compressive modulus of M10Pe5 arrives 23.2 MPa, the specific modulus of which arrives 188 MPa cm3/g, while pure MF aerogel are too fragile to keep intact after freeze-dried. The resulting aerogel has good thermal stability, excellent water resistance (can be second dried with limited strength loss) and low flammability. This partially bio-based novel aerogel with impressive properties is promising in many applications.

Nitric oxide acts upstream of ethylene in cell wall phosphorus reutilization in phosphorus-deficient rice.

Nitric oxide (NO) and ethylene are both involved in cell wall phosphorus (P) reutilization in P-deficient rice; however, the crosstalk between them remains unclear. In the present study using P-deficient 'Nipponbare' (Nip), root NO accumulation significantly increased after 1 h and reached a maximum at 3 h, while ethylene production significantly increased after 3 h and reached a maximum at 6 h, indicating NO responded more quickly than ethylene. Irrespective of P status, addition of the NO donor sodium nitroprusside (SNP) significantly increased while the NO scavenger 2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide (c-PTIO) significantly decreased the production of ethylene, while neither the ethylene precursor 1-aminocyclopropane-1-carboxylic acid (ACC) nor the ethylene inhibitor aminoethoxyvinylglycine (AVG) had any influence on NO accumulation, suggesting NO acted upstream of ethylene. Under P-deficient conditions, SNP and ACC alone significantly increased root soluble P content through increasing pectin content, and c-PTIO addition to the ACC treatment still showed the same tendency; however, AVG+SNP treatment had no effect, further indicating that ethylene was the downstream signal affecting pectin content. The expression of the phosphate transporter gene OsPT2 showed the same tendency as the NO-ethylene-pectin pathway. Taken together, we conclude that ethylene functions downstream of NO in cell wall P reutilization in P-deficient rice.

Immunolocalization of cell wall polymers in grapevine (Vitis vinifera) internodes under nitrogen, phosphorus or sulfur deficiency

The impact on cell wall (CW) of the deficiency in nitrogen (-N), phosphorus (-P) or sulphur (-S), known to impair essential metabolic pathways, was investigated in the economically important fruit species Vitis vinifera L. Using cuttings as an experimental model a reduction in total internode number and altered xylem shape was observed. Under -N an increased internode length was also seen. CW composition, visualised after staining with calcofluor white, Toluidine blue and ruthenium red, showed decreased cellulose in all stresses and increased pectin content in recently formed internodes under -N compared to the control. Using CW-epitope specific monoclonal antibodies (mAbs), lower amounts of extensins incorporated in the wall were also observed under -N and -P conditions. Conversely, increased pectins with a low degree of methyl-esterification and richer in long linear 1,5-arabinan rhamnogalacturonan-I (RG-I) side chains were observed under -N and -P in mature internodes which, in the former condition, were able to form dimeric association through calcium ions. -N was the only condition in which 1,5-arabinan branched RG-I content was not altered, as -P and -S older internodes showed, respectively, lower and higher amounts of this polymer. Higher xyloglucan content in older internodes was also observed under -N. The results suggest that impairments of specific CW components led to changes in the deposition of other polymers to promote stiffening of the CW. The unchanged extensin amount observed under -S may contribute to attenuating the effects on the CW integrity caused by this stress. Our work showed that, in organized V. vinifera tissues, modifications in a given CW component can be compensated by synthesis of different polymers and/or alternative linking between polymers. The results also pinpoint different strategies at the CW level to overcome mineral stress depending on how essential they are to cell growth and plant development.

Two-step sequential cross-linking of sugar beet pectin for transforming zein nanoparticle-based Pickering emulsions to emulgels

Nanosized (<100nm) zein spheres were employed for fabrication of a series of fish O/W Pickering emulsions. Although surface tension measurement informed the high potency of zein particles for interfacial adsorption, the prepared emulsions destabilized shortly. Electrostatic deposition of sugar beet pectin onto zein particles interfacial layer at pH 4.0 increased significantly the emulsion stability which was attributed to enhanced steric and electrostatic repulsions based on ζ-potential measurements. Pectin enrichment also increased the viscosity of the continuous phase of emulsion. Injection of the oxidative enzyme laccase into the pectin-enriched emulsion to cross-link the feruloyl-bearing pectin molecules and the subsequent addition of CaCl2 to set ion-mediated cross-linkages between carboxyl groups of pectin chains transformed Pickering emulsions to emulgels. The higher the pectin content, the shorter was the gelation time of emulsions. The obtained emulgels were self-standing and became harder along with increasing pectin content.

On the stabilisation of calcium-fortified acidified soy milks by pomelo pectin

Although a number of studies existed on the stabilisation of acidified milk with commercial pectin, no data is made available on the stabilising behaviour of pectin from other sources. In this work, we focused on the use of pomelo pectin to stabilise acidified soy milk (ASM) samples with and without calcium fortification. The stability of ASM with varying concentrations of pomelo pectin (0.5–1.5% w/w) was examined through their rheological properties, particle size, and microstructure analyses. It was found that the addition of 0.5% pomelo pectin in ASM sample was not adequate to prevent the aggregation of soy protein during 4 °C storage for up to 15 days. On the contrary, the presence of pectin at 1 and 1.5% stabilised the ASM effectively and no phase separation was observed. All stabilised samples were shown to behave as viscoelastic liquids with its stability enhanced by increasing pectin content. Their flow behaviour was Newtonian with low viscosity of about 0.02–0.06 Pas. Furthermore, the fortification of calcium at 300–1200 mg/l to ASM sample stabilised with 1% pectin did not significantly affect its rheological properties. Additionally, confocal laser scanning microscopy was used to assess protein mobility in the ASM samples. It was found that the microstructure of soy proteins was coarser and more heterogeneous in ASM sample without pomelo pectin addition than that with the pectin stabilisation. The microstructure was also affected by pectin and calcium concentrations. Overall, it can be concluded that pomelo pectin is a promising ingredient for stabilising calcium-fortified ASM without chelating agents.

Novel roles of hydrogen peroxide (H₂O₂) in regulating pectin synthesis and demethylesterification in the cell wall of rice (Oryza sativa) root tips.

Hydrogen peroxide (H₂O₂) has been reported to increase lignin formation, enhance cell wall rigidification, restrict cell expansion and inhibit root elongation. However, our results showed that it not only inhibited rice (Oryza sativa) root elongation, but also increased root diameter. No study has reported how and why H₂O₂ increases cell expansion and root diameter. Exogenous H₂O₂ and its scavenger 4-hydroxy-Tempo were applied to confirm the roles of H₂O₂. Immunofluorescence, fluorescence probe, ruthenium red staining, histological section and spectrophotometry were used to monitor changes in the degree of pectin methylesterification, pectin content, pectin methylesterase (PME) activity and H₂O₂ content. Exogenous H₂O₂ inhibited root elongation, but increased cell expansion and root diameter significantly. H₂O₂ not only increased the region of pectin synthesis and pectin content in root tips, but also increased PME activity and pectin demethylesterification. The scavenger 4-hydroxy-Tempo reduced root H₂O₂ content and recovered H₂O₂-induced increases in cell expansion and root diameter by inhibiting pectin synthesis, PME activity and pectin demethylesterification. H₂O₂ plays a novel role in the regulation of pectin synthesis, PME activity and pectin demethylesterification. H₂O₂ increases cell expansion and root diameter by increasing pectin content and demethylesterification.

Pectin enhances rice (Oryza sativa) root phosphorus remobilization.

Plants growing in phosphorus (P)-deficient conditions can either increase their exploration of the environment (hence increasing P uptake) or can solubilize and reutilize P from established tissue sources. However, it is currently unclear if P stored in root cell wall can be reutilized. The present study shows that culture of the rice cultivars 'Nipponbare' (Nip) and 'Kasalath' (Kas) in P-deficient conditions results in progressive reductions in root soluble inorganic phosphate (Pi). However, Nip consistently maintains a higher level of soluble Pi and lower relative cell wall P content than does Kas, indicating that more cell wall P is released in Nip than in Kas. P-deficient Nip has a greater pectin and hemicellulose 1 (HC1) content than does P-deficient Kas, consistent with the significant positive relationship between pectin and root-soluble Pi levels amongst multiple rice cultivars. These observations suggest that increased soluble Pi might result from increased pectin content during P starvation. In vitro experiments showed that pectin releases Pi from insoluble FePO4. Furthermore, an Arabidopsis thaliana mutant with reduced pectin levels (qua1-2), has less root soluble Pi and is more sensitive to P deficiency than the wild type (WT) Col-0, whereas NaCl-treated WT plants exhibit both an increased root pectin content and an elevated soluble Pi content during P-starvation. These observations indicate that pectin can facilitate the remobilization of P deposited in the cell wall. This is a previously unknown mechanism for the reutilization of P in P-starved plants.

Biochemical and anatomical responses related to the in vitro survival of the tropical bromeliad Nidularium minutum to low temperatures

Nidularium minutum is a tropical bromeliad that grows in natural environment with temperatures ranging from 2 to 30 °C. In the present work we cultivated this species in vitro at 5, 10, 15, and 25 °C for 3 and 6 months aiming at assessing biochemical and morphological responses that allow its survival under low temperatures. No survival was observed for plants cultured constantly at 5 °C and the lowest biometric parameters were found for those grown at 10 °C. A thick aquiferous parenchyma, accumulation of reducing sugars, and increased pectin content in the cell walls were observed in plants grown at 10 and 15 °C when compared to those maintained at 25 °C. In plants cultured at 10 °C, leaf bleaching correlated with low chlorophyll content and lower survival rate after 6 months when compared to those grown at 15 °C. The best in vitro culture condition for slow growth and plant acclimatization was found to be at 15 °C. This probably correlated with the immediate availability of carbon to restore growth during acclimatization and also with higher root initiation under this condition. This study brings information about the responses related to functional adaptation to low temperatures in N. minutum cultured in vitro that can also be implicated in its survival under natural conditions. Additionally, it suggests the best temperature to form a minimal growth collection to be used in restocking and conservation programs for endangered tropical bromeliads.

Physical Properties of Aqueous Solutions of Pectin Containing Sunflower Wax

AbstractThe aim of this study is to investigate the physical properties of aqueous solutions of pectin (PA) containing sunflower wax (SFW), which are used as a basis for producing edible films. The stability and the rheological and microstructural characteristics of SFW/PA mixtures were evaluated. SFW/PA mixtures formed oil‐in‐water emulsions that were milky and opaque in appearance and were stable towards phase separation. Polarized micrographs revealed the presence of wax crystals, whose size decreased as pectin concentration increased. The rheological behavior of the aqueous solutions of pectin containing different amounts of SFW were best described by the generalized power law model of Herschel–Bulkley (H–B), which gave the best fit in all the range of shear rate values. Apparent viscosities and yield stress were determined using this model, and both properties increased with increasing pectin content. The apparent viscosity values were between 0.0095 and 0.1031 Pa s. SFW addition resulted in a small decrease in viscosity for emulsions formulated with 1 and 2 % PA, but the opposite effect was observed for emulsions formulated with 3 % PA. In addition, shear stress values were higher for emulsions with higher PA content, but were not affected by SFW addition.

Synergistic blends of natural polymers, pectin and sodium alginate

AbstractA wide range of Pectin and Sodium Alginate blends have been investigated by casting films from aqueous solution. Blends showed synergy both in mechanical properties and water vapor permeation rate. Previously observed synergism in gels at low pH is also maintained in cast films of blends having up to 40% Pectin. Films were made water‐insoluble by post‐treatment with CaCl2, which develops physical crosslinks among the molecules of both polymers. After CaCl2 treatment, mechanical properties are drastically changed due to development of physically crosslinked tie points in the molecular network structure. The modulus and tensile strength of the resulting network structure are dependent on the nature of the polymers. Even in water insoluble films, synergism in mechanical and water barrier properties is retained in films having up to 20% Pectin content. Structural reorganization before and after CaCl2 treatment was investigated by X‐ray and dynamic mechanical analysis. The synergism observed in mechanical properties of the films before and after CaCl2 treatment is attributed to reduction in molecular mobility and change in molecular network structure. Structural reorganization in CaCl2‐treated films, and thereby film properties, is dependent on the compositions of the blends; blended films show sharp glassy‐rubbery transition in the storage modulus—temperature plot, which is not the case in untreated films. Film flexibility increases with increasing Pectin content in the blends. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011

APPLICATION OF CERTAIN RESISTANCE INDUCERS FOR CONTROLLING FABA BEAN WILT DISEASE UNDER GREENHOUSE AND FIELD CONDITIONS

Fusarium oxysporum f.sp. fabae (Schlecht) Snyder &.Hansen (FOF) is a serious pathogen on faba bean causing wilt disease. In greenhouse experiments, the three tested isolates of the pathogen were differed in their virulence on faba bean cultivars (Giza 29, Giza 4 and Misr 1). Isolate (FF1) was the most virulent one. Faba bean cultivars reacted differently to the infection by FOF isolates. While cv. Misr 1 was the most susceptible one, cvs Giza 29 and Giza 4 showed moderate resistance. In vitro testes, the resistance inducers ascorbic acid (AS) and acetic acid (AA) reduced dry weight of the pathogen followed by salicylic acid (SA) and oxalic acid (OA). Effectiveness of the tested resistance inducers in controlling the disease was tested under greenhouse and field conditions. All applied treatments protected faba bean seedlings against FOF in greenhouse. The most effective treatments were AS and AA treatments, however in field experiments, seed treatments by OA, AA, AS and SA reduced the disease incidence. Almost tested treatments significantly increased cellulose content in treated plants except OA treatment compared with untreated plants. The highest reduction in disease incidence was obtained with AS, AA and SA treatments. Seed treatment with AA and AS significantly increased pectin content in treated plants compared with untreated ones. Faba bean seed treatment with 1 % (AS) exhibited the highest content of lignin, while, seed treatment with 0.25 % (AA) exhibited the lowest lignin levels.

The effect of pectin on the physicochemical and mechanical properties of cement containing boron

The effects of varying concentrations of pectin (0.1–1 wt% of cement) on the properties of ordinary portland cement (PC) and cement containing colemanite ore waste (CW) were investigated. Variation in setting time, compressive strength, and volume expansion of hydrated specimens were determined. It was found that pectin acts as an accelerator for PC cement and as a retarder for CW cement at a level below 0.1%. The inclusion of pectin in PC resulted in a reduction in the early strength of the mortar. However, pectin had positive contribution to the early compressive strength of the CW mortar. The hydration products were also identified by means of X-ray diffraction (XRD) and their microstructure by scanning electron microscopy (SEM). Although the observed hydration products were mostly as expected, due to presence of pectin in the cement paste, the degree to which these phase was present was unusual. In particular, the relative intensity of calcium hydroxide peaks decreased with the increasing pectin content at 2 days curing age.

Effect of Urea, Some Micronutrients, and Growth Regulator Foliar Sprays on the Yield, Fruit Quality, and Some Vegetative Characters of Washington Navel Orange Trees: Fruit Pedicel Pectin Content, Flowering Aspects, and Fruit Set, and Dropping Percentages

This part of the investigation studied the effect of foliar spraying with urea (0.5%); a mixture of Zn (0.4%), Mn (0.3%), Fe (0.5%), and Cu (0.3%) in sulphates (from 23% Zn, 28% Mn, 19% Fe, and 30% Cu, respectively); and two growth regulators (GA3 at 25 ppm and α-NAA at 10 ppm); as well as number and date of sprays on fruit pedicel pectin content, some flowering aspects, and fruit set and drop percentages. Applying urea, micronutrients, or both significantly increased pectin content in the pedicels of the attached and dropped fruit. The treatment including urea plus micronutrients resulted in the highest values for pectin in fruit stem. Either GA3 or NAA significantly raised pectin content over that of the water-sprayed control. However, NAA was more effective in increasing pectin content in fruit pedicel. The overall treatment including urea and micronutrients with GA3 or NAA was the most effective in producing the highest percentage of leafy inflorescence in 1991–92 and 1992–93 seasons. Any nutrition treatment was significantly effective in increasing fruit set and reducing fruit drop compared with the water-sprayed control; however, the treatment including all sprayed nutrients was the most effective. Application of GA3 or NAA significantly increased fruit set percentage and reduced June and preharvest fruit drop; however, NAA was more effective in reducing fruit drop than GA3.

Studies on the relation between pectic substances and stone gum in plum fruits

AbstractA component with electrophoretic mobility identical to authentic gum exudate and to stone gum was present in extracts of plum fruits containing pockets of stone gum, but absent from extracts of fruits lacking visible evidence of gum. The pectin content was greater in fruits showing a higher incidence of gumming. It is concluded that gum is absent from normal fruits, and its production in quantity is associated with an increased pectin content.