Structure and Kinetics of Aggregating κ-Carrageenan Studied by Light Scattering

Abstract

We have studied the evolution in time of the structure factor of aggregating κ-carrageenan using light scattering. Aggregation was induced by cooling solutions containing 0.01 M KCl below a critical temperature. The ionic strength of the solutions was fixed by adding 0.1 M NaCl. Large aggregates consist of locally rigid bundles formed by parallel aggregation of κ-carrageenan. The effect of concentration (C < 0.3 g/L) and temperature on the structure was found to be small. The aggregation rate increases with increasing concentration and decreasing temperature. The optical rotation, i.e., the helix content, is not influenced by aggregation. The molar mass, size, and interactions of nonaggregated κ-carrageenan were determined in the coil and the helix state. For the large molar sample used in this study (M w ) 4.2 × 10 5 g/mol) the molar mass and the size are almost the same in the coil and the helix state.

Relation between structural and release properties in a polysaccharide gel system

“…The κ-Carrageenan powder was dissolved in Millipore deionised water at 70 °C (in the presence of 200 ppm sodium azide as bacteriostatic agent) and stirred at the same temperature for 2 h. [9,11]. The pH of the solution was 8.7 to prevent hydrolysis during preparation [11][12].…”

The study of amorphous aggregation of tobacco mosaic virus coat protein by dynamic light scattering

“…DLS is widely used in biochemistry to measure the size of particles suspended in liquids [16][17][18][19][20][21][22][23][24][25][26][27][28][29]33]. Measured value of the decay rate τ c of the light scattering intensity fluctuations allows finding the diffusion coefficient D of the particles using expression [34]:…”

“…Modern variants of DLS technique allow registering the initial stages of protein aggregation, where the fraction of the aggregated protein constitutes some tenth of a percent of the total amount of the protein in the system. Besides, this method allows quantitative determination of the individual components in heterogeneous populations of aggregates [16][17][18][19][20][21][22][23][24][25][26].…”

Comparative studies on the conformational change and aggregation behavior of irradiated carrageenans and agar by dynamic light scattering

“…Metal ions such as K + , Na + , Li + , and Ca 2+ are said to affect these structure transformations to varying degrees. The conformational associative properties of carrageenan and agar have extensively been studied using several methods including light scattering techniques [1][2][3][4][5][6][7][8][9][10][11][12][13]. Decrease in molecular weight by degradation either by sonolysis or ionizing radiation can also affect so much these transitions [14][15][16].…”