Electric double layer and electrokinetic potential of pectic macromolecules in sugar beet

Abstract

Electrokinetic potential is an important property of colloidal particles and, regarding the fact that it is a well defined and easily measurable property, it is considered to be a permanent characteristic of a particular colloidal system. In fact, it is a measure of electrokinetic charge that surrounds the colloidal particle in a solution and is in direct proportion with the mobility of particles in an electric field. Gouy-Chapman-Stern-Graham's model of electric double layer was adopted and it was proven experimentally that the addition of Cu++ ions to sugar beet pectin caused a reduction in the negative electrokinetic potential proportional to the increase of Cu++ concentration. Higher Cu++ concentrations increased the proportion of cation specific adsorption (Cu++ and H+) with regard to electrostatic Coulombic forces. Consequently, there is a shift in the shear plane between the fixed and diffuse layers directed towards the diffuse layer, i.e. towards its compression and decrease in the electrokinetic potential or even charge inversion of pectin macromolecules

Determination of apple juice authenticity using gas chromatography–mass spectrometry, volt‐ampere and new conductometric methods

“…Among the electrical properties of fruit juices, those most studied are electrokinetic properties. [14][15][16] Such properties of fruit juices substantially depend on the surface charge of SS. It was previously shown 14,17 that the surface of SS of cloudy apple juices is negatively charged (zeta potentials of −21 and −12 mV, respectively).…”

“…Among the electrical properties of fruit juices, those most studied are electrokinetic properties . Such properties of fruit juices substantially depend on the surface charge of SS.…”

The effect of copper ions, aluminium ions and their mixtures on separation of pectin from the sugar beet juice

“…Istraživanjem upotrebe Al 2 (SO 4 ) 3 u toku hemijske obrade melase, nađene su optimalne količine Al 3+ (0.2 < c < 0.4 mol/l) za postizanje nulte vrednosti zeta potencijala [8]. Eksperimentalno je potvrđen GCS model dvojnog električnog sloja kod pektina šećerne repe u prisustvu jona Cu 2+ [6]. Promena zeta potencijala pektinskih makromolekula proporcionalna je količini Cu 2+ dodatih u obliku CuSO 4 .…”

“…U ovom radu je usvojen Gouy-Chapman-Stern-ov (GCS) model dvojnog električnog sloja [3,5]. Potencijal na površini na kojoj je još uvek moguće hidrodinamičko kretanje jona (slika 1, ravan smicanja) lako je merljiva veličina i označava se kao elektrokinetički ili zeta potencijal, ζ [6,7].…”

“…Dovođenjem zeta potencijala blizu nulte vrednosti ostvaruju se uslovi za efikasnu koagulaciju i taloženje [3][4][5][6]. Dodavanjem katjona većeg naelektrisanja dolazi do razelektrisavanja makromolekula.…”