The influence of xanthan andlambda-carrageenan on the creaming and flocculation of an oil-in-water emulsion containing soy protein

Abstract

-The effect of polysaccharide content on the stability of an oil-in-water emulsion (20% oil, droplet diameter 6.5 µm, pH = 7) containing soy protein (5 mg/ml) as the emulsifying agent was studied. Flocculation occurs by addition of two depletion flocculants: xanthan (0.01-0.4%) and λ-carrageenan (0.001-2%). We report that in both cases the onset of flocculation occurs below the overlap polymer concentration (c* = 0.15 % for xanthan and c* = 0.58% for λ-carrageenan). The strength of depletion interaction is dependent on such factors as polymer concentration, molecular weight and also the presence of other macromolecules. Profiles of the creaming behaviour of the sample emulsions were obtained by measuring the height of the boundary between the cream phase and the serum as a function of time for each emulsion. The result indicates that creaming kinetics is dependent on polymer concentration in a complex way. The turbidity of the serum gave an indication of whether the system was fully flocculated or contained flocks together with unflocculated droplets. At very low polymer concentrations the droplets cream individually or in small aggregates at the top of the container. At higher concentrations the droplets appear to cream as a single entity, with a sharp lower boundary separating the cream phase from a clear serum. In these emulsions and in some of the coexistent ones, there is a delay before creaming starts. The presence of the polymers at higher concentrations resulted in a stable emulsion with a very high apparent viscosity for the continuous phase and/or a strong emulsion gel network. The length of the delay phase increased with increasing concentration of both polymers.

Improvement of the flocculation process in water treatment by using moringa oleifera seeds extract

“…The general water treatment consists of both stages. Proteins are known as flocculantinducing agents (Santiago et al, 2002).…”

Improving abamectin bioavailability via nanosuspension constructed by wet milling technique

“…Because abamectin is prone to photolysis in aqueous solution and on leaves under UV radiation, UV329 was added as an ultraviolet absorbent to prevent photo‐decomposition of the pesticide. The water‐soluble carrier sucrose has a role in improving the system suspension and stability by increasing solution viscosity . Therefore, the composition of the abamectin suspension used for wet milling was as follows: 3.0% (w/w) abamectin, 0.3% (w/w) polycarboxylate, 0.3% (w/w) MRES, 0.3% (w/w) UV329, 24.0% (w/w) sucrose and 72.1% (w/w) water.…”

“…The water-soluble carrier sucrose has a role in improving the system suspension and stability by increasing solution viscosity. 32 Therefore, the composition of the abamectin suspension used for wet milling was as follows: 3.0% (w/w) abamectin, 0.3% (w/w) polycarboxylate, 0.3% (w/w) MRES, 0.3% (w/w) UV329, 24.0% (w/w) sucrose and 72.1% (w/w) water.…”

Creaming of skim natural rubber latex with chitosan derivatives

“…[21][22][23][24] According to this mechanism, when pairs of rubber particles approach within a distance of less than the mean diameter of free CMCh molecules in the latex, the CMCh molecules will be depleted from between the rubber particles. The osmotic pressure between the particles is, therefore, lower than the pressure around them, and the water will flow out from the particles.…”