pectins and beta-glucono-1-5-lactone

In this study, the physicochemical properties of pectin from Nicandra physalodes (Linn.) Gaertn. seeds (NPGSP) were analysed firstly, and the rheological behavior, microstructure and gelation mechanism of NPGSP gels induced by Glucono-delta-lactone (GDL) were investigated. The hardness of NPGSP gels was increased from 26.27 g to 226.77 g when increasing GDL concentration from 0 % (pH = 4.0) to 1.35 % (pH = 3.0), and the thermal stability was improved. The peak around 1617 cm

Topics: Adsorption; Pectins; Seeds; Solanaceae

Gelation properties of pectic polysaccharide extracted with ammonium oxalate from soybean hulls assisted by microwave were seldom studied. Water mobility in soy hull pectic polysaccharide (SHPP) was firstly studied by low field NMR. D-Glucono-1,5-lactone (GDL) and sucrose both could decrease spin-spin relaxation times (T2) of SHPP solutions which indicated the SHPP network formed. Rheological analysis conformed that SHPP gel was formed induced by GDL and enhanced by sucrose. Urea can increase T2 and collapse the network of SHPP. TGA was used to draw the profiles of water desorption from SHPP solutions or gels, during heating at a controlled rate. It was found that sucrose increased the bound water content and urea acted a conversely role. Hydrogen bond is the main force to maintain SHPP gel network.

Topics: Gels; Gluconates; Glycine max; Industrial Waste; Lactones; Pectins; Rheology; Sucrose; Urea

The complexation between bovine serum albumin (BSA) and sugar beet pectin (SBP) was studied in situ by coupling glucono-δ-lactone (GDL) induced acidification with dynamic light scattering and turbidity measurements. Individual measurements at specific pHs and mixing ratios were also carried out using zeta potentiometry, gel permeation chromatography-multiangle laser light scattering (GPC-MALLS), and isothermal titration calorimetry (ITC). These investigations together enabled the establishment of a phase diagram of BSA/SBP and the identification of the molecular events during protein/polysaccharide complexation in relation to the phase diagram, which showed five regions: (I) a stable region of mixed individual soluble polymers, (II) a stable region of intramolecular soluble complexes, (III) a quasi-stable region of intermolecular soluble complexes, (IV) an unstable region of intermolecular insoluble complexes, and (V) a second stable region of mixed individual soluble polymers, on lowering pH. We found for the first time that the complexation could take place well above the critical pH(c), the value that most previous studies had regarded as the onset occurrence of complexation. A model of structural transitions between the regions was proposed. The borderline between region II and region III represents the BSA/SBP stoichiometry for intramolecular soluble complex at a specific pH, while that between region III and region IV identifies the composition of the intermolecular insoluble complex. Also studied was the effect of NaCl and CaCl(2) on the phase diagram and structural transitions.

Topics: Animals; Beta vulgaris; Calcium Chloride; Calorimetry; Cattle; Chromatography, Gel; Gluconates; Hydrogen-Ion Concentration; Lactones; Lasers; Light; Pectins; Phase Transition; Scattering, Radiation; Serum Albumin, Bovine; Sodium Chloride; Solubility

High- and low-methoxyl pectins were treated with pectin methylesterase (PME) and the functional properties of the resulting pectin gels were characterized. The degree of esterification of high- and low-methoxyl pectins decreased from 74.5% to 6.3% and 40.0% to 6.5%, respectively while not changing their molecular weight. Also, the addition of glucono-delta-lactone (GDL) dramatically affected the gel strength and the pH reduction by the GDL led to the increased syneresis of the pectin gels, which was also observed in the PME-treated samples. When flavor compounds were incorporated into the pectin gels, the flavor release from the gels increased with decreasing the degree of esterification due to increased hydrophilic properties.

Topics: Carboxylic Ester Hydrolases; Esterification; Flavoring Agents; Gels; Gluconates; Hardness; Hydrogen-Ion Concentration; Lactones; Molecular Weight; Pectins; Solutions