Rheology of decane/water and triglyceride/water emulsions stabilized by β-casein and sodium caseinate

Abstract

Emulsões estabilizadas por -caseína e sódio caseinato tiveram suas propriedades reológicas investigadas em função da natureza da fase oleosa, da força iônica e do pH. Fases oleosas de características estruturais distintas, a saber, decano e óleos vegetais de alto teor triglicerídico, foram ensaiadas. A emulsificação dos sistemas contendo decano foi significativamente mais efetiva do que aquela das amostras contendo triglicérides. Efeitos de pH e força iônica mostraram-se relativamente pouco importantes sobre a capacidade emulsificante da proteína. As propriedades reológicas foram marcadamente distintas em cada caso, com estruturas de caráter sólido (G´>> G´´) sendo produzidas com decano, diferentemente do que foi observado para amostras contendo triglicérides, nas quais a viscoelasticidade não foi nem mesmo aparente. A relevância de aspectos espaciais da estrutura da fase oleosa no desenvolvimento do caráter viscoelástico é discutida. Propõe-se que os fatores responsáveis pelo comportamento distinto observado residam possivelmente na interface gotícula/meio dispersante, inacessível por microscopia óptica, e guardam pouca relação com tamanho ou forma da gotícula.-Casein and sodium caseinate stabilized emulsions were produced and had their rheological properties investigated as a function of the nature of the oil phase, ionic strength and pH. Oil phases of distinct structural characteristics, namely decane and vegetable oil of high triglyceride content, were assayed. The former was much more effectively emulsified than the latter. Effects of pH and ionic strength were minor. Emulsion rheological properties were strikingly distinct in each case, with viscoelastic, solid-like structures being formed with decane (G´>> G´´), differently from what is observed for samples containing triglycerides as the oil phase, in which viscoelasticity was not even apparent. The relevance of the spatial features of the oil phase structure in the development of the emulsion viscoelastic character is discussed. Factors responding for the system distinct behaviour possibly reside at the emulsion droplet interface, unapproachable by optical microscopy, rather than on aspects related to particle size or shape.

Effects of Extrusion on the Emulsifying Properties of Rumen and Soy Protein

“…Decane was employed as a lipid phase as it generates more stable protein emulsions than those observed when vegetable oils are used. 19 Protein particle size was standardized by milling, sieving, and classifying the material: particle size <0.177 mm was used. During stirring for emulsion preparation, flasks were periodically immersed in cold water, to avoid unwanted heating.…”

“…Rheological measurements were performed essentially as described before 19 in an Anton Paar Physica MCR-300 instrument. Temperature of experiments was 20.00±0.01°C.…”

The influence of asphaltenes subfractions on the stability of crude oil model emulsions

“…11,12 Emulsion destabilization can be achieved by different methods. [13][14][15] Crude oil can be demulsified by adding chemical compounds (normally at concentrations of 10 to 1000 ppm) to improve the separation rate of the W/O emulsion. These additives cause thinning of the interfacial film, allowing the droplets to coalesce more easily, thus allowing the phases to separate.…”

Influence of casein and different supplements into stability of Corn Oil/Water emulsions

“…The small amount of oil and missing of starch and KCl as additions lead to large particles. It was worth to note that differences in emulsification capacity were mainly related to the nature of the oil phase, and not to pH (Figueiredo et al 2008). Such interactions between casein, oil and water involve the hydrophobic domains of the casein molecules, in particular the hydrophobic terminal end of the casein fraction and the non-polar molecules leads to bad adsorption of casein in O/W emulsions.…”