Search

Protein rich (F1) and protein poor (F4) fractions of sugar beet pectin (SBP). Protein rich F1, protein poor F4, and control SBP were used to make oil-in-water emulsions with 0.5% or 1.5% SBP (F1_0.5, F1_1.5, F4_0.5, F4_1.5 or C_1.5) and 15% (medium chain triglyceride) MCT oil and emulsifying activity was determined. Changes in D[4,3], light microscopy and rheological parameters during storage at 32 °C for 10 days indicated that SBP fraction and concentration influenced emulsion stability. Emulsions prepared with 0.5% fraction F4_0.5, with lower protein and surface hydrophobicity, had a D[4,3] values less than 1 μm, which remained the same during storage. D[4,3] values of emulsions, prepared with the 1.5% fraction F1_1.5 with higher protein and surface hydrophobicity, increased from 1.42 to 2.09 μm at 10 d. Emulsions prepared with unfractionated control SBP were intermediate in particle size. Emulsions prepared with F4_1.5 and F1_0.5 had higher D[4,3] values of 3.45 and 4.18 μm after 10 d, respectively. There were no significant changes in viscosities of individual emulsions over 10 days. Emulsions were shear thinning or near Newtonian. Protein poor Fraction F4 with greater hydrophile/lipophile ratio formed more stable emulsions at 0.5%, but not at 1.5%, compared to protein rich Fraction F1 at 1.5%. [ABSTRACT FROM AUTHOR]

Pectin is a complex structural polysaccharide located in the cell wall and middle lamella of higher plants. The homogalacturon (HG) regions may be methyl esterified or de-esterified to create a block co-polymer structure. The HG backbone may be interrupted by neutral sugar side chains forming the rhamnogalacturon I (RGI) region, or rhamnogalacturon II (RGII), a conserved structure. In addition, protein, ferulic acid and acetyl groups may be found on some sources of pectin. While pectin has positive health effects against many diseases related to inflammation and as a delivery vehicle for bioactives for colon targeted delivery, conflicting results are reported and may be related to paucity of physico-chemical information or source of pectin. Pectin structure can be enzymatically or chemically modified to produce molecular fragments that can be used to successfully entrap phytochemicals for emulsion based targeted delivery to the colon. Likewise, charge modified pectin allows the development of delivery systems based on hydrogel technology. Pectin is recognized as a soluble dietary fiber, and likely has multiple outcomes against cardiovascular disease. More recent evidence also points to the role of neutral sugars, arabino-oligosaccharides, and ferulic acid and other phenolics associated with pectin as a dietary fiber and in vitro fermentability of selected domains of pectin and associated colonic metabolites on inflammation and gut health. While the mechanism of the positive effects of pectin remain to be elucidated, emerging evidence points to synergism between specific domains of pectin structure and other food constituents. [ABSTRACT FROM AUTHOR]

Abstract: Laccase catalyzes intermolecular cross-links between ferulic acid of sugar beet pectin (SBP). Conjugation of SBP by laccase was confirmed by increased molecular weight, monitored by size exclusion chromatography, combined with multi-angle laser light scattering (SEC–MALLS), by reduced ferulic acid concentration detected at UV 325 nm, as well as by increased particle size. In addition, cross-linked SBP developed a more compact, branched structure as verified by a smaller root mean square (RMS) when molecular weight increased. Emulsions prepared with conjugated SBP had significantly smaller d 4,3 diameter and uniform droplet size, with more negative ζ-potential than non-treated SBP, during 30 days storage at 37 °C. The d 4,3 diameter was 5.3 μm and 3.8 μm for SBP and conjugated SBP, respectively. Covalently conjugated SBP has increased functionality and improved emulsion stability, most likely attributable to development of thick layer at the oil interface. [Copyright &y& Elsevier]

Abstract: The interaction of non-fat dry milk, caseinate and casein (CSN) fractions with charge modified pectins (B-Pec and U-Pec) and unmodified pectin (O-Pec) in acidified dispersion systems was investigated. U-Pec led to more precipitation of proteins than O-Pec or B-Pec. Casein dispersions with pectin had larger particle size, especially U-Pec and B-Pec, than dispersions without pectin. Dispersions with charge modified pectins showed more negative ζ-potential than dispersions with unmodified pectin or dispersions without pectin. U-Pec enhanced negative ζ-potential of β-CSN more than B-Pec. There was no significant difference in flow behavior among non-fat milk samples regardless of pectins added. In contrast, non-Newtonian behavior, shear thinning behavior was observed in modified pectin added κ-CSN. Analysis by light microscopy of non-fat milk and κ-CSN showed that sizes and shapes were changed by addition of O-Pec and U-Pec. The results suggest a specific affinity between pectin and κ-CSN, which is related to the charge distribution of pectin. [ABSTRACT FROM AUTHOR]

Abstract: Pectin was de-esterified by U-PME or B-PME, pectinesterases that differed in cationic character and peptide composition. Pectin fractions of unmodified (O-Pec) and Valencia PME modified pectins (B-Pec and U-Pec) were separated by ion exchange (IEX) chromatography and characterized for calcium sensitivity by ζ-potential, texture profile analysis (TPA), and viscoelastic properties. U- and B-Pec had more negative ζ-potential than O-Pec, and became increasingly negative at higher pH values. Without CaCl2, viscosity of O-Pec was higher than B- and U-Pec. With 35mM CaCl2, B- and U-Pec gelled, but O-Pec did not gel. TPA values were not significantly different between B-Pec and U-Pec. The G'' values of O-Pec was 20–50-fold lower than G'' for B-Pec or U-Pec. After separation with ion exchange chromatography, later eluting fractions formed stronger gels than earlier eluting fractions. However, pectin fractions had lower viscosity and G'' values than unfractionated pectin, which is likely related to molecular weight differences. Results show that U-Pec forms stronger gels than B-Pec that is related to length of charge block and numbers of de-esterified pectin molecules. [Copyright &y& Elsevier]

The effect of pectin composition on the binding selectivity to anthocyanins was investigated by Langmuir isotherms with two blueberry pectins, water soluble fraction (WSF) and chelator soluble fraction (CSF). Adsorption was four times higher between CSF and anthocyanins, than WSF and anthocyanins. Higher adsorption was attributed to the more linear, more negatively charged homogalacturonan region of CSF, compared to the more branched, neutral sugar rich WSF. The CSF binding sites ( q m a x ) to anthocyanins were estimated at 1413–1904 μg/mg pectin, which was about eight times higher than WSF binding sites. No difference was observed in binding affinity (K L) among blueberry pectins. WSF, rich in neutral sugar side chains, showed lower and more variable interaction with anthocyanins. Binding studies also showed that blueberry pectin-anthocyanins adsorption was highest at pH 3.0 and lowest at pH 4.0. Increasing concentration from 25 to 200 mM citrate-phosphate (CP) weakened the pectin-anthocyanins interaction between pH values 3.0 and 4.0. However, no significant difference in binding was observed at pH 2.6 with increasing CP. As pH values changed from 4.0 to more acidic pH, electrostatic interaction decreased while hydrophobic interactions increased between blueberry pectin and anthocyanins, and hydrogen bond likely remained constant. Putative health benefits of anthocyanins are probably influenced by small pH and ionic strength changes in food matrixes. Image 1 • Binding sites and affinity of anthocyanins and blueberry pectins vary • Anthocyanins bound more linear and more negatively charged pectin structure • Increasing ionic strength weakens chelator fraction-anthocyanins interaction • Decreasing pH strengthens hydrophobic or π-interaction of pectin-anthocyanins [ABSTRACT FROM AUTHOR]

Abstract Blueberry powder was sequentially fractionated to water (WSF), chelator (CSF) and sodium carbonate (NSF) soluble fractions. Uronic acid content was above 22 μg/mg AIS. The 4% potassium hydroxide (4KSF) and 24% potassium hydroxide (24KSF) soluble fractions were hemicellulose rich fractions. Cell wall glycan-directed monoclonal antibodies (mAbs) based glycome profiling analyses revealed that WSF, CSF and NSF fractions had epitopes of homogalacturonan (HG), arabinogalactan (AG), and xyloglucan (XG), but no xylan. 4KSF and 24KSF fractions had higher abundance of xyloglucan and xylan epitopes in addition to pectic epitopes. Arabinose and galactose were the two major neutral sugars in the WSF, CSF, and NSF. Xylose represented about 70 mol% neutral sugar in 4KSF and 24KSF fractions. Increased flexibility and presence of protein likely influence the propensity of pectin to bind anthocyanins. Graphical abstract Image 1 Highlights • Water soluble blueberry fraction has lower than 50% DE. • Water soluble fraction is rich in xyloglucans, low in homogalactan. • Chelator soluble fraction is rich in xyloglucan, rhamnogalactan and xylan. • Protein content is higher in alkali soluble fraction. • Increased protein and flexibility of pectin may increase anthocyanin binding. [ABSTRACT FROM AUTHOR]

Isopropanol was used to sequentially precipitate sugar beet pectin (SBP) and generate six fractions that varied in galacturonic acid, protein, ferulic acid and other physic–chemical characteristics. Protein was high in Fractions 1 and 2 at 209 and 154 μg/mg alcohol insoluble solids (AIS), respectively. Fractions 3, 4, and 5 had lower protein values of 77–106 μg/mg AIS; the protein content was 87 μg/mg AIS in unfractionated control. Ferulic acid content in Fraction 1 was 93 μg/mg AIS and at least three times higher than measured in other fractions. The degree of esterification in Fraction 1 was 11% and ranged from 46 to 74% in later precipitating fractions. The relative fluorescence with an external probe for hydrophobicity ranged from 159 to 254 in F1, F2 and F3 compared to negligible values in later fractions. The ζ-potential ranged from −25 to −33 mV and was not different between fractions or control. Molecular weight analysis indicated highly heterogenous pectin (Mw/Mn greater than 2.5) with MW values of 398,630, 543,900, and 442,330 g/mol for F1, F4 and control, respectively. FTIR analysis confirmed that F1 and F2 were richer in protein. SBP that precipitated at the lowest isopropanol addition had the greatest protein, ferulic acid content, particle size, relative fluorescence intensity and lowest uronic acid content and degree of esterification. The type and/or nature of protein in F1 and F4 is likely different. Isopropanol fractionation resulted in SBP fractions with unique physico–chemical properties. [ABSTRACT FROM AUTHOR]

Sugar Beet Pectin (BP) was sequentially fractionated with increasing isopropanol into six fractions from a commercial BP control (BP2–C) and denoted as BP2–F1 to BP2–F6. Fractions of BP2 were categorized based on physico-chemical characteristics of similar protein and ferulic acid content, varying galacturonic acid, surface hydrophobicity, degree of esterification and molecular weight. Glycan-directed monoclonal antibodies response showed intense binding for homogalacturonan, rhamnogalacturonan I and arabinogalactan epitopes that varied between early and later precipitating fractions, and between lots of BP. In a 14-day study of rice bran oil-in-water emulsion, the particle size (2 ± 0.3 μm) and ζ-potential (−34 ± 3 mV) remained stable for BP2–F3 and B2–F4. Fractions that precipitated at lower alcohol concentrations likely have more amphiphilic properties, compared to later precipitating fractions that provide more steric stabilization. [Display omitted] • Sequential isopropanol fractionation of beet pectin (BP) resulted in two populations. • Emulsifying stability was associated with amphiphilic BP and steric stabilization. • Glycome profiling provided comprehensive view of cell wall glycan epitopes. • Glycome profiles were unique for BP controls and fractions. [ABSTRACT FROM AUTHOR]

Abstract: The molecular weight (MW) distribution of whey proteins (WP) mixed with various pectins was investigated using size exclusion chromatography (HPSEC) combined with multi-angle laser light scattering (MALLS). Samples were prepared with 1, 2, 5, 8% WP and 1% pectin. Mixtures were studied at pH 6.0 and CaCl2 concentrations of 0, 5, 10mM. Aggregate formation was determined after heating at various temperatures. The interactions between WP and low methoxyl pectin were observed before heat treatment. In the absence of calcium, mixing pectins with WP increased the average molecular weight of the aggregates, but the degree of methoxylation of pectins did not affect the MW distribution of the aggregates. On the other hand, in the presence of calcium, low and high methoxyl pectins generated different molecular weight distributions. In addition, the presence of low methoxyl pectin seemed to have a protective effect on WP, as the aggregates showed a smaller molecular weight and a smaller peak. [Copyright &y& Elsevier]