Binding of calcium and lead ions to carboxystarch prepared by action of nitrogen dioxide on native starch and its 2,3-dialdehyde derivatives

1986 ◽  
Vol 51 (6) ◽  
pp. 1340-1351 ◽  
Author(s):  
Rudolf Kohn ◽  
Karol Tihlárik
Keyword(s):  
Nitrogen Dioxide ◽  
Alkaline Medium ◽  
Binding Capacity ◽  
Lead Ions ◽  
Carbonyl Groups ◽  
Weakly Alkaline ◽  
Exchange Cations ◽  
Counter Ions ◽  
The Stability ◽  
Derivatives Of

The binding of calcium and lead ions to carboxy derivatives of starch prepared by allowing nitrogen dioxide to act on native maize starch (procedure A) and on starch 2,3-dialdehyde derivatives of degrees of oxidation DO(d.a.) ≥ 0.94 (procedure B) was studied. The carboxy group content of the samples in the H+ form was 4.6 - 12.1 mmol g-1. The effect of alkaline medium on the stability of the carboxy derivatives and on their ability to bind and exchange cations was examined. The Ca2+ → 2K+ exchange was evaluated in terms of the decrease in the electrostatic free enthalpy Δ(Gel/N)KCa, determined by alkalimetric potentiometric titrations, and the binding of Pb2+ ions was evaluated in terms of the activity of the Pb2+ counter-ions determined in suspensions of Pb salts of the carboxy derivatives by means of an ion specific electrode. The IR and CD spectra revealed that the carboxystarch preparations obtained by procedure A contained, in addition to free carboxy groups, a considerable amount of carbonyl groups. During the conversion of the latter groups to the former, even in a weakly alkaline medium, the carboxy derivatives undergo an appreciable degradation and lose, to a great extent, their ability to bind and exchange cations. Procedure B, on the other hand, leads to highly selective starch and amylose carboxy derivatives, exhibiting a small amount of carbonyl groups and featuring a relative stability towards alkaline medium; their binding capacity is as high as 12 milliequivalents of cations per g of sample.

Polarographische Untersuchungen zur Bestimmung der Stabilität von Metall-Protein-Bindungen / Polarographic Investigations for the Determination of the Stability of Metal-Protein Bonds

1989 ◽  
Vol 44 (7) ◽  
pp. 767-771 ◽  
Author(s):  
H. Reinecke ◽  
L. Dunemann ◽  
G. Schwedt
Keyword(s):  
Oxalic Acid ◽  
Chelating Agents ◽  
Binding Capacity ◽  
Soya Bean ◽  
Buffer System ◽  
Bean Flour ◽  
Model Substances ◽  
The Stability ◽  
Derivatives Of

Bonds between metals (especially copper) and a protein fraction (18,100 g/mol) of a soya bean flour extract have been investigated. The binding capacity (304 nmol Cu/mg protein) and the binding stability (K = 1,046·103 in an ammonia buffer system) were determined by polarographic investigations. Changes in the polarogram caused by spiking the protein with metal ions were compared with effects in model substances. Cysteine, ethylenediamine, oxalic acid and derivatives of benzoic acid were used as chelating agents. The effects of functional groups on the metalprotein bonds were estimated by the determination of their different binding stabilities.

scholarly journals Antioxidant Network Based on Sulfonated Polyhydroxyalkanoate and Tannic Acid Derivative

2021 ◽  
Vol 8 (1) ◽  
pp. 9
Author(s):  
Laura Brelle ◽  
Estelle Renard ◽  
Valerie Langlois
Keyword(s):  
Gallic Acid ◽  
Tannic Acid ◽  
Water Soluble ◽  
Gel Formation ◽  
Ene Reaction ◽  
Inorganic Cations ◽  
Medium Chain Length ◽  
Physically Crosslinked ◽  
The Stability ◽  
Derivatives Of

A novel generation of gels based on medium chain length poly(3-hydroxyalkanoate)s, mcl-PHAs, were developed by using ionic interactions. First, water soluble mcl-PHAs containing sulfonate groups were obtained by thiol-ene reaction in the presence of sodium-3-mercapto-1-ethanesulfonate. Anionic PHAs were physically crosslinked by divalent inorganic cations Ca2+, Ba2+, Mg2+ or by ammonium derivatives of gallic acid GA-N(CH3)3+ or tannic acid TA-N(CH3)3+. The ammonium derivatives were designed through the chemical modification of gallic acid GA or tannic acid TA with glycidyl trimethyl ammonium chloride (GTMA). The results clearly demonstrated that the formation of the networks depends on the nature of the cations. A low viscoelastic network having an elastic around 40 Pa is formed in the presence of Ca2+. Although the gel formation is not possible in the presence of GA-N(CH3)3+, the mechanical properties increased in the presence of TA-N(CH3)3+ with an elastic modulus G’ around 4200 Pa. The PHOSO3−/TA-N(CH3)3+ gels having antioxidant activity, due to the presence of tannic acid, remained stable for at least 5 months. Thus, the stability of these novel networks based on PHA encourage their use in the development of active biomaterials.

Electrolysis soy protein isolate-based oleogels prepared with an emulsion-templated approach

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Dianyu Yu ◽  
Yan Chen ◽  
Xing Chen ◽  
Yunyan Huang ◽  
Liqi Wang ◽  
...  
Keyword(s):  
Soy Protein ◽  
Xanthan Gum ◽  
Binding Capacity ◽  
Soy Protein Isolate ◽  
Single Layer ◽  
Protein Isolate ◽  
Regulatory Limits ◽  
Order Of Magnitude ◽  
The Stability ◽  
Oil Binding

Abstract This research focuses on the use of protein-polyphenol complex and protein-polyphenol: polysaccharide complexes to prepare oleogels through an emulsion-templated approach. Electrolysis soy protein isolate (ESPI) could be effectively adsorbed on the surface of a single-layer emulsion to increase the particle size. The order of the negative charges of the emulsion after adding polysaccharides was xanthan gum (XG)> pectin> carboxymethyl cellulose (CMC). Rheological behavior showed that the stability of the double-layer emulsions increased, and the viscoelasticity increased around one order of magnitude with the addition of polysaccharides. The oil binding capacity (OBC) of the oleogel prepared by adding polysaccharides increased to more than 97%. The peroxide value (PV) and anisidine value (AV) of XG oleogel were the minimum values in all samples. The AV and POV were within the regulatory limits of China after storage for 21 days. This provides a reference to design of ESPI-based oleogel for different applications.

Acclimation to hard or soft water at weakly alkaline pH influences gill permeability and gill surface calcium binding in rainbow trout (Oncorhynchus mykiss)

1995 ◽  
Vol 52 (12) ◽  
pp. 2583-2593 ◽  
Author(s):  
Deke T. Gundersen ◽  
Lawrence R. Curtis
Keyword(s):  
Rainbow Trout ◽  
Oncorhynchus Mykiss ◽  
Calcium Binding ◽  
Binding Capacity ◽  
High Hardness ◽  
Alkaline Ph ◽  
Surface Binding ◽  
Weakly Alkaline ◽  
Rainbow Trout Oncorhynchus Mykiss ◽  
Osmotic Water

Rainbow trout (Oncorhynchus mykiss) were acclimated for 10 d to soft (0.1 mM as CaCO3) or hard (1.0 mM as CaCO3) water at weakly alkaline pH (8.06–8.34). Following acclimation, individual gill arches were removed for examining the effects of low hardness or high hardness acclimation on gill water permeability, gill Ca2+ interactions, and gill aluminum interactions. Isolated gill arches were exposed to water of varying Ca2+ (0.0–1.0 mM) and aluminum (3.7–37 μM) concentration for osmotic permeability experiments. High hardness acclimated gills had significantly greater percent weight gain over time caused by osmotic water entry than low hardness acclimated gills, when exposed to distilled water (32.34 ± 1.15 and 24.86 ± 0.62%, respectively, after 60-min incubations); these differences were absent when Ca2+ (0.1–1.0 mM) was added to the incubation medium. Gill arch Ca2+ binding experiments resolved two gill surface binding site populations, which differed in their Ca2+ binding affinity. The higher affinity sites were probably associated with gill membrane permeability, because low hardness acclimated gills had more such sites (binding capacity, 0.322 ± 0.027 μmol Ca2+∙g−1) and less permeable gills than high hardness acclimated gills (binding capacity, 0.198 ± 0.004 μmol Ca2+∙g−1). Aluminum had little influence on gill permeability and gill Ca2+ binding.

scholarly journals Potentiometric Response of Ag/AgCl Chloride Sensors in Model Alkaline Medium

2018 ◽  
Vol 2018 ◽  
pp. 1-12 ◽  
Author(s):  
Farhad Pargar ◽  
Hristo Kolev ◽  
Dessi A. Koleva ◽  
Klaas van Breugel
Keyword(s):  
Alkaline Medium ◽  
Open Circuit Potential ◽  
Dynamic Equilibrium ◽  
Chloride Concentration ◽  
Chloride Content ◽  
Cementitious Materials ◽  
Open Circuit ◽  
Potentiometric Response ◽  
Before And After ◽  
The Stability

The stability and reproducibility of an Ag/AgCl sensors’ response in an alkaline medium are important for the application of these sensors in cementitious materials. The sensors’ response, or their open circuit potential (OCP), reflects a dynamic equilibrium at the sensor/environment interface. The OCP response in an alkaline medium is affected by the presence of hydroxide ions. The interference of hydroxide ions leads to inaccuracies or a delay in the sensors’ response to a certain chloride content. In this article, the potentiometric response (or OCP evolution) of the chloride sensors is measured in model solutions, resembling the concrete pore water. The scatter of the sensors’ OCP is discussed with respect to the interference of hydroxide ions at varying chloride concentration in the medium. The deviation of the sensor’s response from its ideal performance (determined by the Nernst law) is attributed to dechlorination of the AgCl layer and the formation of Ag2O on the sensor’s surface. Results from the surface XPS analysis of the AgCl layer before and after treatment in alkaline medium confirm these observations in view of chemical transformation of AgCl to Ag2O.

scholarly journals Energetics of carbohydrate binding by a 14 kDa S-type mammalian lectin

1995 ◽  
Vol 308 (1) ◽  
pp. 237-241 ◽  
Author(s):  
R Ramkumar ◽  
A Surolia ◽  
S K Podder
Keyword(s):  
Binding Constants ◽  
Van Der Waals Interactions ◽  
Titration Calorimetry ◽  
Carbohydrate Binding ◽  
Glucose Binding ◽  
The Stability ◽  
L 14 ◽  
Derivatives Of ◽  
Binding Lectin ◽  
Site Binding

The thermodynamics of the binding of derivatives of galactose and lactose to a 14 kDa beta-galactoside-binding lectin (L-14) from sheep spleen has been studied in 10 nM phosphate/150 mM NaCl/10 mM beta-mercaptoethanol buffer, pH 7.4, and in the temperature range 285-300 K using titration calorimetry. The single-site binding constants of various sugars for the lectin were in the following order: N-acetyl-lactosamine thiodigalactoside > 4-methylumbelliferyl lactoside > lactose > 4-methylumbelliferyl alpha-D-galactoside > methyl-alpha-galactose > methyl-beta-galactose. Reactions were essentially enthalpically driven with the binding enthalpies ranging from -53.8 kJ/mol for thiodigalactoside at 301 K to -2.2 kJ/mol for galactose at 300 K, indicating that hydrogen-bonding and van der Waals interactions provide the major stabilization for these reactions. However, the binding of 4-methylumbelliferyl-alpha-D-galactose displays relatively favourable entropic contributions, indicating the existence of a non-polar site adjacent to the galactose-binding subsite. From the increments in the enthalpies for the binding of lactose, N-acetyl-lactosamine and thiodigalactoside relative to methyl-beta-galactose, the contribution of glucose binding in the subsite adjacent to that for galactose shows that glucose makes a major contribution to the stability of L-14 disaccharide complexes. Observation of enthalpy-entropy compensation for the recognition of saccharides such as lactose by L-14 and the absence of it for monosaccharides such as galactose, together with the lack of appreciable changes in the heat capacity (delta Cp), indicate that reorganization of water plays an important role in these reactions.

Methoxy-substituted derivatives of 1,4-bis(2-phenylethenyl)benzene and of 1,4-bis(2-phenylethyl)benzene as ligands in ion-selective electrodes for lead ions

2001 ◽  
Vol 18 (1-2) ◽  
pp. 171-176 ◽  
Author(s):  
Iwona Szymańska ◽  
Katarzyna Ocicka ◽  
Hanna Radecka ◽  
Jerzy Radecki ◽  
H.J. Geise ◽  
...  
Keyword(s):  
Lead Ions ◽  
Ion Selective Electrodes ◽  
Derivatives Of

Determination of Stability Derivatives by Impulse-Response Techniques

1977 ◽  
Vol 14 (02) ◽  
pp. 265-275
Author(s):  
Carl A. Scragg
Keyword(s):  
Memory Effect ◽  
Impulse Response ◽  
Traditional Method ◽  
Equations Of Motion ◽  
Experimental Results ◽  
Regular Motion ◽  
Stability Derivatives ◽  
The Stability ◽  
Derivatives Of

This paper presents a new method of experimentally determining the stability derivatives of a ship. Using a linearized set of the equations of motion which allows for the presence of a memory effect, the response of the ship to impulsive motions is examined. This new technique is compared with the traditional method of regular-motion tests and experimental results are presented for both methods.

scholarly journals Phytochemical Molecules from the Decarboxylation of Gomphrenins in Violet Gomphrena globosa L.—Floral Infusions from Functional Food

2020 ◽  
Vol 21 (22) ◽  
pp. 8834
Author(s):  
Natalia Drobnicka ◽  
Katarzyna Sutor ◽  
Agnieszka Kumorkiewicz-Jamro ◽  
Aneta Spórna-Kucab ◽  
Michał Antonik ◽  
...  
Keyword(s):  
Citric Acid ◽  
High Resolution Mass Spectrometry ◽  
Potential Health ◽  
Gomphrena Globosa ◽  
Brewing Process ◽  
Health Promoting ◽  
The Stability ◽  
Kinetics Of ◽  
Derivatives Of

Herein, the generation of decarboxylated derivatives of gomphrenin pigments exhibiting potential health-promoting properties and the kinetics of their extraction during tea brewing from the purple flowers of Gomphrena globosa L. in aqueous and aqueous citric acid solutions were investigated. Time-dependent concentration monitoring of natural gomphrenins and their tentative identification was carried out by LC-DAD-ESI-MS/MS. The high content of acylated gomphrenins and their principal decarboxylation products, 2-, 15-, 17-decarboxy-gomphrenins, along with minor levels of their bidecarboxylated derivatives, were reported in the infusions. The identification was supported by the determination of molecular formulas of the extracted pigments by liquid chromatography coupled with high-resolution mass spectrometry (LCMS-IT-TOF). The influence of plant matrix on gomphrenins’ stability and generation of their derivatives, including the extraction kinetics, was determined by studying the concentration profiles in the primary and diluted infusions. Isolated and purified acylated gomphrenins from the same plant material were used for the preliminary determination of their decarboxylated derivatives. The acylated gomphrenins were found to be more stable than nonacylated ones. Citric acid addition had a degradative influence on natural gomphrenins mainly during the longer tea brewing process (above 15 min); however, the presence of plant matrix significantly increased the stability for betacyanins’ identification.

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