scholarly journals The Effect of Concentration on the Cross-Linking and Gelling of Sodium Carbonate-Soluble Apple Pectins

Molecules ◽  
2019 ◽  
Vol 24 (8) ◽  
pp. 1635 ◽  
Author(s):  
Diana Gawkowska ◽  
Jolanta Cieśla ◽  
Artur Zdunek ◽  
Justyna Cybulska
Keyword(s):  
Light Scattering ◽  
Sodium Carbonate ◽  
Cross Linking ◽  
Scattering Method ◽  
Ph Measurements ◽  
Aggregation Index ◽  
Dynamic Light Scattering Method ◽  
Atomic Force ◽  
Low Degree ◽  
The Cross

The cross-linking and gelation of low-methoxy pectins are basic processes commonly used in different industries. The aim of this research was to evaluate the cross-linking process of the sodium carbonate-soluble pectins (named DASP) extracted from apples, characterized by a low degree of methylesterification as a function of its concentration in water (CDASP). The cross-linking process was studied with a dynamic light scattering method, atomic force microscope (AFM), viscosity and pH measurements. An increase in CDASP above 0.01% resulted in a decrease in the aggregation index (AI) and the change of its sign from positive to negative. The value of AI = 0 occurred at CDASP = 0.33 ± 0.04% and indicated the formation of a pectin network. An increase in CDASP caused the changes in viscosity of pectin solutions and the nanostructure of pectins spin-coated on mica observed with AFM, which confirmed results obtained. The hydrogen bonds were involved in the cross-linking process.

scholarly journals PECULARITIES OF MICELLE FORMATION OF PENTACYCLIC GLYCOSIDES IN AQUEOUS SOLUTIONS

2021 ◽  
Vol 64 (4) ◽  
pp. 26-33
Author(s):  
Natalia V. Mironenko ◽  
Irina V. Shkutina ◽  
Vladimir F. Selemenev
Keyword(s):  
Surface Tension ◽  
Light Scattering ◽  
Dynamic Light Scattering ◽  
Aqueous Solutions ◽  
Hydrodynamic Radius ◽  
Critical Concentration ◽  
Micelle Formation ◽  
Cylindrical Shape ◽  
Scattering Method ◽  
Dynamic Light Scattering Method

The regularities of changes in structural characteristics during the formation of associates in micellar aqueous solutions of triterpene saponins Quillaja Saponin and Sapindus Mukorossi are considered. The dependence of surface tension and adsorption on the concentration of an aqueous saponin solution is analyzed, and the values of surface activity and parameters of the adsorption layer are calculated. The average values of diffusion coefficients for spherical and cylindrical micelles are determined based on the measurement of the solution viscosity. The effect of the electrolyte solution on the surface tension and viscosity of glycoside solutions is studied: when the electrolyte is introduced into the saponin solution, the surface tension decreases, which leads to a shift in the critical concentration of micelle formation towards lower concentrations. The introduction of potassium chloride electrolyte reduces the degree of ionization and, as a result of suppressing the electroviscosity effect, leads to a decrease in the viscosity of the solution. The dynamic light scattering method is used to determine the size of glycoside aggregates. It is established that there are aggregates of several sizes in an aqueous solution of saponin. The size and shape of aggregates were calculated using the concepts of micelle packing parameters. In the region of very low concentrations of glycoside solutions, when approaching the critical concentration of micelle formation in the solution, there are spherical micelles. A further increase in the saponin concentration in the solution leads to a decrease in the content of structures with a hydrodynamic radius of 50-80 nm and the appearance of larger agglomerates with sizes greater than 100 nm. It was found that micelles acquire a less hydrated and more densely packed cylindrical shape in the concentration range of 1.7-2.6 mmol/dm3. Compaction of associates leads to an increase in the content of particles with a hydrodynamic radius of 150-250 nm and larger ones, and their presence predicts the appearance of larger agglomerates. Analyzing the data obtained using the dynamic light scattering method, it can be concluded that aggregates of several sizes co-exist in the volume of aqueous saponin solutions at certain concentrations.

Features of the Aggregation of С70 Fullerene in an o-Xylol Solution Revealed by the Dynamic Light Scattering Method

JETP Letters ◽  
2018 ◽  
Vol 108 (10) ◽  
pp. 680-685
Author(s):  
A. V. Arutyunyan ◽  
E. I. Zavatskii ◽  
V. S. Kozlov ◽  
M. V. Suyasova
Keyword(s):  
Light Scattering ◽  
Dynamic Light Scattering ◽  
Scattering Method ◽  
Dynamic Light Scattering Method

High-throughput dynamic light scattering method for measuring viscosity of concentrated protein solutions

2010 ◽  
Vol 399 (1) ◽  
pp. 141-143 ◽  
Author(s):  
Feng He ◽  
Gerald W. Becker ◽  
Jennifer R. Litowski ◽  
Linda O. Narhi ◽  
David N. Brems ◽  
...  
Keyword(s):  
Light Scattering ◽  
Dynamic Light Scattering ◽  
High Throughput ◽  
Protein Solutions ◽  
Scattering Method ◽  
Dynamic Light Scattering Method

scholarly journals Interaction between DNA and Trimethyl-Ammonium Bromides with Different Alkyl Chain Lengths

2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
Chao Cheng ◽  
Shi-Yong Ran
Keyword(s):  
Surfactant Concentration ◽  
Alkyl Chain ◽  
Scattering Method ◽  
High Concentration ◽  
Dna Structures ◽  
Dynamic Light Scattering Method ◽  
Atomic Force ◽  
Chain Lengths ◽  
Dna Complex ◽  
Long Alkyl Chain

The interaction betweenλ—DNA and cationic surfactants with varying alkyl chain lengths was investigated. By dynamic light scattering method, the trimethyl-ammonium bromides-DNA complex formation was shown to be dependent on the length of the surfactant’s alkyl chain. For surfactants with sufficient long alkyl chain (CTAB, TTAB, DTAB), the compacted particles exist with a size of ~60–110 nm at low surfactant concentrations. In contrast, high concentration of surfactants leads to aggregates with increased sizes. Atomic force microscope scanning also supports the above observation. Zeta potential measurements show that the potential of the particles decreases with the increase of surfactant concentration (CTAB, TTAB, DTAB), which contributes much to the coagulation of the particles. For OTAB, the surfactant with the shortest chain in this study, it cannot fully neutralize the charges of DNA molecules; consequently, the complex is looser than other surfactant-DNA structures.

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