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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]

Sugar beet pectin (SBP) and β-lactoglobulin (BLG) contain ferulic acid and tyrosine, respectively, potential substrates for laccase. Dispersions of BLG were treated with laccase and/or heat and SBP to assess potential for ferulic acid in SBP to influence laccase conjugation of BLG. Changes were investigated by size exclusion chromatography combined with multi angle laser light scattering (HPSEC-MALLS), refractive index (RI) and UV detector, particle size and ζ-potential analysis. Molecular weight (MW) of BLG decreased from 3.7 × 104 to 2.9 × 104 and root mean square (RMS) decreased from 41 to 36 after laccase treatment. The slope of a conformation plot increased from 0.35 to 0.72, indicating a change in shape in laccase treated BLG to more random coil. While laccase did not affect MW of BLG, MW of BLG increased after sequential heat and laccase treatment to 2.9 × 106 and 4.4 × 106, respectively. Free thiol (SH) increased by heat and laccase treatment of BLG; tyrosine in BLG increased only by heat. An increased MW and decreased ferulic acid in SBP was observed in the presence of BLG and laccase. The increase in MW was attributed to entrapment of BLG in SBP cross-linked matrix catalyzed by laccase. [ABSTRACT FROM AUTHOR]

Laccase, an oxidative enzyme, was used to catalyze the hetero and homo covalent conjugation between ferulic acid in sugar beet pectin (SBP) and tyrosine in heated β-lactoglobulin (H_BLG). The conjugation of SBP and H_BLG was confirmed by peak position using size exclusion chromatography, multi angle laser light scattering, refractive index, and UV detection. H_BLG, pre-treated with laccase, eluted at an earlier volume with greater UV280 absorbance than non-laccase treated dispersions. Tyrosine decreased in H_BLG that contained laccase treated SBP samples. Heat enhanced exposure of tyrosine in BLG and improved conjugation with SBP by laccase. H_BLG·SBP conjugates with laccase had improved solubility than laccase untreated dispersions at pH values near the isoelectric point of BLG. [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]

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]