High Methoxy Pectin Research Articles

Effect of high-pressure homogenization on stability of emulsions containing zein and pectin

The aim of this study was to investigate the effect of high-pressure homogenization on the droplet size and physical stability of different formulations of pectin–zein stabilized rice bran oil emulsions. The obtained emulsions, both before and after passing through high-pressure homogenizer, were subjected to stability test under environmental stress conditions, that is, temperature cycling at 4 °C/40 °C for 6 cycles and centrifugal test at 3000 rpm for 10 min. Applying high-pressure homogenization after mechanical homogenization caused only a small additional decrease in emulsion droplet size. The droplet size of emulsions was influenced by the type of pectin used; emulsions using high methoxy pectin (HMP) were smaller than that using low methoxy pectin (LMP). This is due to a greater emulsifying property of HMP than LMP. The emulsions stabilized by HMP–zein showed good physical stability with lower percent creaming index than those using LMP, both before and after passing through high-pressure homogenizer. The stability of emulsions after passing through high-pressure homogenizer was slightly higher when using higher zein concentration, resulting from stronger pectin–zein complexes that could rearrange and adsorb onto the emulsion droplets.

Pectin-silica gels as matrices for controlled drug release in gastrointestinal tract

The synthesis of pectin-silica gels for controlled drug release in gastrointestinal tract (GIT) using low methoxyl (LM) and high methoxy (HM) pectins and tetraethoxysilane (TEOS) as precursor is described. The FTIR spectra of the pectin-silica gels show intense absorption bands at 1246cm−1 and 802cm−1 corresponding to the vibrations COSi bonds, which absent in the FTIR spectra of the native pectins that indicate the formation covalent bond between silica and pectin macromolecules in the pectin-silica gels. Pectin-TEOS, pectin-Ca-TEOS and pectin-TEOS-Ca beads with mesalazine are synthesized by different combinations of sol-gel method using TEOS and ionotropic gelation method using calcium chloride. The best resistant of pectin-TEOS and pectin-Ca-TEOS beads during incubation in simulated gastric fluid for 2h and subsequently in simulated intestinal fluids for 18h is indicated. Pectin-TEOS beads are characterized by higher encapsulation efficiency (to 28%) than pectin-Ca-TEOS beads (to 16%). The drug release of pectin-silica beads in simulated GIT occurs gradually up to 80% and is directly dependent on the hardness of the beads. The surface morphology of beads is shown. The use of pectin-silica beads is promising with regard to the development of controlled release of drug formulations.

Utilization of tomato peel waste from canning factory as a potential source for pectin production and application as tin corrosion inhibitor

BackgroundThe possibility of utilizing the bioorganic tomato peel as a cheap source for pectin production and its application as a corrosion inhibitor was investigated to implement viable cyclical economy principle in solving the main problem of waste disposal. MethodologyPectin, from two batches (A and B) from canning factory, was extracted in two steps with ammonium oxalate/oxalic acid, under reflux. Physico-chemical properties, characterisation of structure (FTIR and NMR spectroscopy) and application as corrosion inhibitor of pure tin for isolated pectin were investigated. ResultsThe highest pectin yield of 32.6 and 31.9% in two batches, respectively, but the lowest pectin quality, i.e. methoxy and anhydrouronic acid contents and degree of esterification, were obtained in the second extraction step, which points out that higher pectin yields are not necessarily connected with higher pectin quality. The results of total anhydrouronic acid content for batches A (52.9%) and B (39.6%) show that sample origin have a considerable effect on pectin quality. Degree of esterification around 82% categorizes extracted pectin as high methoxy pectin. Corrosion results point out that pectin is efficient inhibitor (73%) even at very low concentrations, much better then commercially available pectin. ConclusionAccording to chemical profile, rheological properties and structural characterisation of extracted pectins, it can be concluded that tomato peel is a suitable source for pectin isolation. The obtained results show that under-utilised biomass waste from tomato canning industry can be used for development of new generation of corrosion inhibitors and as valuable additive in food industry.

Orange pectin mediated growth and stability of aqueous gold and silver nanocolloids

The role of orange based pectin in the nucleation and growth of silver and gold nanoparticles is addressed. Pectin is a complex polysaccharide found in fruits such as oranges, lemons, passion fruits or apples. It displays smooth and hairy chain regions containing hydroxyl-, ester-, carboxylate- and eventually amine groups that can act as surface ligands interacting under various pH conditions more or less efficiently with growing nanometals. Here, a high methoxy pectin (>50% esterified) was used as a stabilizer/reducing agent in the preparation of gold, silver and silver–gold nanoparticles. Commercial pectin (CP) and pectin extracted from orange bagasse (OP) were used. Optionally, trisodium citrate or oxalic acid we used to reduce AgNO3 and HAuCl4 in aqueous environment. Characterization methods included UV–vis absorption spectroscopy, transmission electron microscopy, electron diffraction and energy-dispersive X-ray spectroscopy. The results show that under different pH conditions, pectin and reducing agents allow producing various nanostructures shapes (triangles, spheres, rods, octahedrons and decahedrons) often with high polydispersity and sizes ranging between 5nm and 30nm. In addition, depending on Ag/Au-ratio and pH, the surface plasmon bands can be continuously shifted between 410nm and 600nm. Finally, pectin seems to be a highly efficient stabilizer of the colloidal systems that show a remarkable stability and unchanged optical spectral response even after five years.

Fermentation Patterns of Various Pectin Sources by Human Fecal Microbiota

High Methoxy Pectin (HMP), Sugar Beet Pectin (SBP), Soy Pectin (SOY), and Fructooligosaccharide (FOS, as a positive control) were used to determine fermentation properties considering applicabil-ity as functional foods, particularly related to colon health. Certain beneficial effects of carbohy-drates in humans can be postulated as being due to microorganisms and metabolites (short-chain fatty acids (SCFAs)). Fecal samples were collected and incubated anaerobically with HMP, SBP, SOY, and FOS at 37 °C. The average degree of polymerization (DP) of HMP, SBP, and SOY was 492, 3729, and 1510, respectively. Degree of pectin methylation of each sample was 76.0% (HMP), 21.2% (SBP), and 22.8% (SOY). Total SCFAs in SOY showed the highest value compared to other samples, especially having the highest concentration of propionic acid (P < 0.05). While fermentation with FOS showed higher butyrate production, the total SCFAs with SOY, HMP, and SBP were significantly higher than FOS over 30 h (P < 0.05). From the denaturing gradient gel electrophoresis (DGGE) analysis, changes of microbiota composition were found. In conclusion, pectin samples, especially soy pectin, stimulated production of total SCFAs and composition of human fecal microbiota was modulated. Therefore, pectin samples may alter the composition of fecal microbiota and improve the colonic health.

Preservation of oleic acid entrapped in a condensed matrix of high-methoxy pectin with glucose syrup

This investigation deals with the diffusional mobility of essential fatty acids in triglyceride form (oleic acid) from a condensed matrix comprising 3% (w/w) high-methoxy pectin and 81% (w/w) co-solute (glucose syrup) to absolute ethanol. Work utilises rheological measurements in shear, differential scanning calorimetry, ESEM, FTIR and WAX diffraction to identify the molecular properties of the composite system. Results showed that the amorphous carbohydrate matrix underwent vitrification at −15 °C (mechanical Tg) calculated mathematically using the Williams, Landel and Ferry (WLF) and modified Arrhenius equations. Diffusion kinetics of the fatty acid (monitored via UV-vis spectroscopy) was combined with the newly introduced concept of spectroscopic shift factor to demonstrate that, although the increment of oleic acid mobility appeared to respond to the predicted glass transition temperature, this is distinct from the structural relaxation of the matrix. Experimental observations were further treated with the concept of diffusion coefficient to provide an estimate of the transport rate of the triglyceride as a function of time or temperature of observation within the glass transition region.

Diffusion kinetics of ascorbic acid in a glassy matrix of high-methoxy pectin with polydextrose

The relative mobility of ascorbic acid incorporated in a condensed matrix of high-methoxy pectin (HMP) and polydextrose is reported. Physicochemical and structural characterisation of the high-solid systems utilised modulated differential scanning calorimetry, small deformation dynamic oscillation in shear, scanning electron microscopy, Fourier transform infrared spectroscopy and wide angle X-ray diffraction. Theoretical modeling of the thermomechanical measurements demonstrated that the mechanism of free volume governs stress relaxation phenomena of the polymeric system through the process of vitrification yielding the mechanical glass transition temperature. Combination of UV-vis spectrophotometry and a vitamin-dye binding method was employed to follow for 60 min the diffusion process of ascorbic acid from the concentrated HMP/polydextrose matrix to the absolute ethanol phase throughout the temperature range of −30 to 20 °C. A relatively low estimate of activation energy for the diffusion of vitamin C reflects its freedom of mobility and high free volume, as compared to the relaxation of the polymeric system that exhibits strong temperature dependence in the glass transition region. Utilisation of the concept of diffusion coefficient sheds further light into the relationship between free volume of the polymeric system and diffusional mobility of the micronutrient.

Preparation and optimization of soy protein isolate–high methoxy pectin microcapsules loaded with Lactobacillus delbrueckii

SummaryThis study was aimed to use soy protein isolate (SPI) and high methoxy pectin (HMP) as encapsulating materials for probiotic bacterial (Lactobacillus delbrueckii) delivery systems. The encapsulation conditions were optimised, and scanning electron microscopy (SEM) was used to characterise the microstructural changes of the microcapsule. The results showed that the optimal conditions for microcapsule preparation were 90 mg mL−1 SPI and 1 mg mL−1 HMP, with a SPI/HMP ratio of 7:1 (v/v), and a L. delbrueckii suspension to SPI–HMP complex ratio of 1:1 (v/v). The viability of the probiotics in the microcapsules reaching the small intestine was 3 log CFU mL−1 higher than that of naked bacteria. SEM showed that the surface of the SPI–HMP compound microcapsules was smooth and that a large number of L. delbrueckii could be seen in cross‐sections of the microcapsules.

Oil-filled hydrogel particles for reduced-fat food applications: Fabrication, characterization, and properties

The food industry needs effective strategies to develop reduced calorie products with desirable sensory attributes. This study utilizes controlled phase separation of biopolymer mixtures to form oil-filled hydrogel particles suitable for use in food products. Filled hydrogel particles were fabricated from fat droplets (0 to 1%), sodium caseinate (1.5 to 3%) and high-methoxy pectin (1.5 to 3%) mixtures (pH 5) using two different approaches: multistep and simple methods. The multistep method involved inducing segregative phase separation of the mixed biopolymers at pH 7 (due to electrostatic repulsion), and then reducing to pH 5 to promote aggregative phase separation (due to electrostatic attraction). The simple method involved mixing all the components together at pH 7 and then adjusting to pH 5. The oil-filled hydrogel particles were spheroid in shape, with mean particle diameters (d43) around 10 μm. They consisted of fat droplets trapped within caseinate-rich hydrogel particles that were dispersed within a pectin-rich phase. The hydrogel particles increased the lightness and viscosity of aqueous solutions, and may therefore be suitable to replace fat droplets or starch granules in reduced calorie products. The food industry needs effective strategies to develop reduced calorie products with desirable sensory attributes. This study utilizes controlled phase separation of biopolymer mixtures to form oil-filled hydrogel particles suitable for use in food products. They consisted of fat droplets trapped within caseinate-rich hydrogel particles dispersed within a pectin-rich phase. The hydrogel particles increased the lightness and viscosity of aqueous solutions, and may be suitable to replace fat droplets or starch granules within reduced calorie products.

The effect of pectin and other constituents on the antioxidant activity of tea

The effect of pectin on the antioxidant capacity and phenolic content of black, green, mountain tea and Pelargonium purpureum infusions was investigated. Antioxidant capacity was determined by the Ferric Reducing Antioxidant Power (FRAP) assay and total phenolics by the Folin-Ciocalteu method. Green tea was the richest in phenolics and had the highest antioxidant capacity, followed by black and the remaining two infusions. High methoxy pectin, added at various concentrations, did not affect the studied properties of all the infusions. As a further step, milk, lemon juice or sugars (sucrose, fructose) were added to black and green tea infusions, in the presence and absence of pectin. For green tea infusions, no significant differences were reported for the studied properties, for all the constituents, both in the presence and absence of pectin. For black tea infusions statistically different values were observed when pectin was combined with the constituents. These results suggest that pectin does not mask the antioxidant capacity of tea infusions and therefore, it may be added to tea infusions for stabilizing or thickening reasons and create new food formulations with improved health benefits.

Effect of Pectin Type on Association and pH Stability of Whey Protein—Pectin Complexes

The purpose of this study was to investigate the influence of pectin type on complex formation between whey protein isolate (WPI) and high methoxy pectins with varying degrees of esterification (DE), and their pH stability. The biopolymer particles with protein-to-polysaccharide mass ratio set to 2:1 were formed at pH 3–7 by heating at 85 °C for 20 min. The particle size, electrical charge, turbidity and microstructure of the biopolymer complexes were evaluated. The optimal conditions for forming WPI-pectin complexes were at the initial pH of 4.5–4.75, just below the isoelectric point of the WPI, where complex formation occurs. At this pH range, the smallest biopolymer complexes (d = 225–300 nm) could be created. Pectins with 50, 55, 62 and 70 % DE formed relatively small and monomodal complexes with WPI, except for pectin with 71 % DE, which showed major aggregation. The pH stability against aggregation was best with the biopolymer complexes assembled from pectins with 50 % DE (stable at pH 3.5–6.0) and with 62 % DE (stable at pH 3.0–6.0). The results suggest that pectins with varying DE can be used to form small particles and therefore can offer new possibilities in designing novel hierarchical structures and delivery systems.

In vitro fermentation of various pectin substrates by human fecal microbiota

Metabolic activity of the gut microbiota is formation of short chain fatty acids (SCFAs). SCFA contribute to human healthy by serving as an energy source for intestinal epithelial cells and inhibiting pathogenic growth by lowering pH in the intestinal lumen. The aims of this study were to assess the short chain fatty acids production of various pectin samples (High Methoxy Pectin (HMP), Sugar Beet Pectin (SBP), and Soy pectin (SOY)) and to determine the composition of gut microbiota. Fructooligosaccharide (FOS, known prebiotic) was used as a control. Fresh feces were collected from 4 healthy men and incubated anaerobically with various substrates at 37°C. Culture aliquots were taken at 0, 6, 12, 24, and 30 h. SCFAs were measured by GC. FOS resulted in higher butyrate production and decreased the production of acetate compared with other pectin treatments (P&lt;0.05). Compared with other treatments, incubation with SOY showed significantly greater propionate production (P&lt;0.05). Denaturing gradient gel electrophoresis (DGGE) fingerprint analysis showed a distinct profile of fecal microbiota with different samples. The findings indicate that consuming different types of pectin substrates might affect fecal microbiota composition and enhance the production of SCFAs. Funding provided by Arkansas Soybean Promotion Board is greatly appreciated.

Combined dietary effects of supplemental threonine and purified fiber on growth performance and intestinal health of young chicks

Characterization of intestinal health in poultry has become imperative as specialized ingredients become more common in poultry diets. We tested whether purified fiber affects dietary Thr requirements and intestinal morphology of young chicks. In experiment 1, three diets containing 7% added silica sand (control), cellulose, or high-methoxy pectin were used. Six replicate pens of 6 chicks received dietary treatments through d 14 posthatch, at which time growth performance and nutrient digestibility were determined. In experiment 2, the effect of purified fiber on dietary Thr requirements was determined using a Thr-deficient basal diet (3.2 g of Thr/kg of diet) and 7 graded levels of supplemental Thr (0 to 9.6 g/kg of diet). Six replicate pens of 5 chicks were tested from d 8 to 21 posthatch, and ileal tissue was collected at the conclusion of the study for histological evaluation. In experiment 1, pectin reduced (P < 0.05) weight gain, feed efficiency, DM digestibility, and AME(n) compared with the control diet. In experiment 2, supplemental Thr requirements were estimated by fitting growth performance data to a 1-slope, broken-line (i.e., piece-wise) regression model. For the control and cellulose- and pectin-containing diets, supplemental Thr requirements were estimated at 3.64, 2.60, and 2.38 g of Thr/kg of diet, and at 778, 737, and 576 mg of supplemental Thr intake over the 21-d study, respectively, based on BW gain. For histological measures, crypts were deepest (P < 0.03) in the cellulose treatment; total goblet cell count and density were highest (P < 0.03) in the pectin-fed birds, and mixed goblet cell counts were highest (P < 0.03) in the control treatment. The serosa was thickest in the cellulose treatment with adequate supplemental Thr, and acidic and neutral goblet cell counts were highest in the control treatment with adequate Thr supplementation (fiber × Thr, P < 0.05). These findings suggest both dietary Thr concentration and fiber source affect growth performance, intestinal morphology, and mucin secretion in young chicks, which may directly affect poultry feeding strategies.

Modulation of the intestinal environment, innate immune response, and barrier function by dietary threonine and purified fiber during a coccidiosis challenge in broiler chicks

Coccidiosis is a major contributor to economic losses in the poultry industry due to its detrimental effects on growth performance and nutrient utilization. We hypothesized that the combined effects of supplemental dietary Thr and purified fiber may modulate the intestinal environment and positively affect intestinal immune responses and barrier function in broiler chicks infected with Eimeria maxima. A Thr-deficient basal diet (3.1 g of Thr/kg of diet) was supplemented with 70 g/kg of silica sand (control) or high-methoxy pectin and 1 of 2 concentrations of Thr (1.8 or 5.3 g/kg of diet; 4 diets total), and fed to chicks from hatch to d 16 posthatch. On d 10 posthatch, chicks received 0.5 mL of distilled water or an acute dose of Eimeria maxima (1.5 × 10(3) sporulated oocytes) with 6 replicate pens of 6 chicks per each of 8 treatment combinations (4 diets and 2 inoculation states). Body weight gain, feed intake, and G:F increased (P < 0.01) with addition of 5.3 g of Thr/kg of diet. Eimeria maxima schizonts were present only in intestinal tissue sampled from infected birds (P < 0.01). Weights of cecal digesta were highest (P < 0.01) in pectin-fed birds, and ceca with the heaviest weights also had the highest concentrations of total short-chain fatty acids. Expression of interleukin-12 in ileal mucosa was highest (P < 0.01) in infected birds receiving the control diet with 5.3 g of supplemental Thr/kg. In cecal tonsils, interferon-γ expression was highest in infected birds receiving the control diet (fiber × infection, P < 0.05); interferon-γ expression was lowest in infected birds fed the high Thr diet (Thr × infection, P < 0.05). There were no differences due to infection or Thr supplementation for cytokine expression in birds fed pectin-containing treatments. Overall, we conclude that although pectin has some protective function against coccidiosis, Thr supplementation had the greatest effect on intestinal immune response and maintenance of near normal growth in young broiler chicks infected with E. maxima.

Fermentative Capacity of Three Strains of Lactobacillus Using Different Sources of Carbohydrates: In Vitro Evaluation of Synbiotic Effects, Resistance and Tolerance to Bile and Gastric Juices

&lt;p&gt;A fermentation study of three probiotic &lt;em&gt;Lactobacillus&lt;/em&gt; strains was conducted on individual carbohydrates including glucose (GLU) high methoxy pectin (HMP), sugar beet pectin (SBP), fructooligosaccharide (FOS), galactooligosaccharide (GOS), and inulin agave (IA) as the sole carbon sources. It was observed that &lt;em&gt;Lactobacillus bulgaricus &lt;/em&gt;(LB), &lt;em&gt;Lactobacillus casei&lt;/em&gt; (LC) and &lt;em&gt;Lactobacillus delbruckii&lt;/em&gt; (LD) achieved the highest growth rates when they were grown in the presence of GLU, FOS, and IA, but LB had a slower growth rate in these substrates compared to LC and LD. Only LC had a statistically significantly higher growth rate in GOS than in the basal medium which contained no carbohydrate source. Exposure to bile caused a significant reduction of log colony forming units/ml of all 3 strains, with LD grown in HMP exhibiting the highest survival followed by LC and LD grown in GLU, and LD grown on IA. Although HMP was not fermented by the test organisms, results indicate that HMP may in fact help certain probiotic bacteria to survive exposure to bile. Exposure to simulated gastric juices indicated that the studied &lt;em&gt;Lactobacilli&lt;/em&gt; are tolerant to simulated gastric juice.&lt;/p&gt;

Calcium cation triggers and accelerates the gelation of high methoxy pectin

The gelation of high methoxyl (HM) pectin has been found to be affected by Ca2+, but the acting mechanism of the Ca2+ in the gelation is still unclear. In order to explore the role of Ca2+ in the gelation of HM pectin, aqueous systems composed of HM pectin and CaCl2 were investigated in comparison with alginate-CaCl2 systems through a Ca2+-concentrating gelling process (CCGP) that is our newly developed gelation method based on water evaporation. A HM pectin solution (1%) formed gels in the presence of Ca2+ (2.72 μmol/mL) during water evaporation manifesting the participation of Ca2+ in the CCGP of HM pectin. Additionally, the same amount of Ca2+ induced more dramatic changes in the flow index n, consistency index k, and loss angle δ of the HM pectin samples than those of the alginate samples suggesting that the molecular interactions of HM pectin are likely strengthened by Ca2+. After similar percentages of water were evaporated, the HM pectin-Ca2+ sample showed a δ value of 29° while the δ value of the Ca2+-free HM pectin sample was 65°, indicating that Ca2+ triggers and accelerates the gelation of HM pectin. The absence of an optimal concentration ratio of HM pectin to Ca2+ and the high Ca2+ content released from the HM pectin gel suggest that the structuring of HM pectin molecules by Ca2+ is realized through a non-specific binding and an electrostatic screening effect facilitating their hydrophobic interactions during CCGP to form gels.

Effect of high methoxy pectin and sucrose on pasting, rheological, and textural properties of modified starch systems

AbstractMixtures of high methoxy pectin, sucrose, and cross‐linked potato starch (acetylated distarch phosphate (ADP) and acetylated distarch adipate (ADA)) at concentrations of 2.5, 3.5, and 4.5% w/w were used to produce pastes and gels, which were characterized by RVA, steady shear, and oscillatory rheological measurements, and by textural testing. The pectin and sucrose components of the paste and gels affected their rheological and textural properties. The effect of starch concentration on the pasting parameters of the starch–pectin–sucrose systems depended on both amount of added starch and kind of modified starch, however, for each starch concentration both peak and final viscosities of the mixed systems were greater than these of the respective starch alone pastes. A domination of elastic properties over viscous features (G′&gt;G″) were observed in the starch–pectin–sucrose systems, with increase in the values of storage and loss moduli with increase in starch concentration. The mixed systems appeared to be more rigid during the extrusion than the starch alone gels, with the values of textural parameters increasing with increase in starch concentration more in ADP than ADA systems.

Preparation and evaluation of pectin-based colon-specific pulsatile capsule in vitro and in vivo

The purpose of this study was to develop and evaluate a colon-specific, pulsatile drug delivery system, which consists of an impermeable capsule body filled with a 5-aminosalicylic acid rapid-disintegrating tablet and a pectin-based erodible plug placed in the opening of the capsule body. To obtain an appropriate gel-forming ability and suitable lag time for the colon-specific drug delivery, high-methoxy pectin (HM-pectin) was formulated with lactose and lowmethoxy pectin (LM-pectin) with HPMC to prepare the plug tablet. In order to evaluate the lag time, prior to the rapid drug release, both the formulation of the plug tablet and in vitro release medium were studied. The lag time prior to the rapid drug release was mainly determined by the HM-pectin/lactose or LM-pectin/HPMC ratio. The addition of pectinase or rat cecal content into the release medium shortened the lag time significantly, which predicted the probable enzyme sensitivity of pectin plug tablet. In vivo studies showed that the plasma concentration of drug can only be detected 6h after oral administration of the pulsatile capsule, which indirectly proved the colon-specific characteristics. These results show that the pulsatile capsule may have the therapeutic action for colon-specific drug delivery.

Pectin methyl esterase treatment on high‐methoxy pectin for making fruit jam with reduced sugar content

Pectin methyl esterase (PME) has been postulated to catalyse the transacylation reaction between pectin molecules. The present study aimed to prove the occurrence of this reaction. The feasibility of applying PME-catalysed transacylation between high-methoxy pectin molecules in making fruit jam with reduced sugar content was also investigated. PME treatment increased the turbidity and particle size in pectin solution and the molecular weight of pectin, while it decreased the number of methoxy ester linkages and the intensity of the CH₃ absorption peak in the Fourier transform infrared spectrum without changes in the number of total ester linkages in pectin molecules. These findings support the occurrence of PME-catalysed transacylation between pectin molecules. Higher values of hardness, gumminess and chewiness were found in a jam containing PME-treated citrus pectin (10 g L⁻¹) and sugar (350 g L⁻¹) as compared with either a jam containing untreated citrus pectin (10 g L⁻¹) and sugar (350 g L⁻¹) or strawberry jam containing pectin (10 g L⁻¹) from the fruit and sugar (650 g L⁻¹). The demand for sugar in jam making can be greatly reduced by the use of PME-treated high-methoxy pectin.

Analysis on the effectiveness of co-solute on the network integrity of high methoxy pectin

Co-solute requirements for high methoxy pectin gelation were observed by the addition of glucose syrup and polydextrose at concentrations varying from 50% to 78% (w/w). Pectin content was fixed at 2% (w/w) in formulations. Studies from small deformation dynamic oscillation in shear, modulated differential scanning calorimetry and environmental scanning electron microscopy are reported. Structural properties of pectin preparations were recorded in relation to the molecular weight and concentration of added co-solute in an acidic environment (pH ∼3.0). High levels of co-solute induce formation of weak pectin gels at elevated temperatures (even at 95°C), which upon subsequent cooling exhibit increasing strength and convert to a clear glass at subzero temperatures. Fourier Transform Infrared Spectroscopy and wide angle X-ray diffraction were practised to examine the nature of interactions between polymer and co-solute and the extent of amorphicity of preparations. Glucose syrup is an efficient plasticiser leading to a reduction in the glass transition temperature (Tg) of the pectin network, whereas polydextrose assists in the formation of stronger pectin gels in the rubbery state.