Use Cases 

What are the interfacial properties of lipase generated molecules during fat digestion ? 

Reference: Adsorption of Polar Lipids at the Water-Oil Interface. P. Reis; R. Miller; M. Leser; H. Watzke; V. B. Fainerman; K. Holmberg; Langmuir 2008, 24, 5781-5786.

The interfacial properties of lipase generated molecules during fat digestion are probed using the pendant drop technique (TRACKER™ automatic drop tensiometer by TECLIS).  Fatty acid salts, monoglycerides and diglycerides of different chain lengths have been probed at a phosphate buffer-decane interface as individual surfactants and mixtures. Fitting the experimental date (adsorption isotherms and dynamic surface tension curves) with theoretical model allowed to further characterize the interfacial properties of these surfactants. The results of this study showed that monoglycerides have considerably higher interfacial activity than fatty acid salts and diglycerides. In the case of a mixture, this means that the monoglycerides will expel both the fatty acid and the diglyceride from the interface.

TECLIS product: TRACKER™ automatic drop tensiometer

Key words: Surface tension, adsorption kinetics, lipids, water-oil Interface,  pH, Langmuir model, Frumkin model for a mixture

What is the effect of the oil type of the network formation of heat-set protein aggregates

Reference: The effect of oil type on network formation by protein aggregates into oleogels. A. d. Vries; Y. L. Gomez; E. v. d. Linden; E. Scholten; The Royal Society of Chemistry 2017, 7, 11803–11812

In this article, the effect of the oil type on the network formed by heat-set protein in liquid oil is studied. Whey protein and 4 different oils (medium chain triglyceride oil, sunflower oil, extra virgin olive oil and castor oil) have been used. A first step consisted in probing the water-oil interfacial properties of these oils. The table on the right shows the water-oil surface tension measured at t=1h with an automatic drop tensiometer (TRACKER™ by TECLIS). These measurements give valuable information on the polarity of the tested oils since an increase of the equilibrium water-oil surface tension within a group is correlated to  a decrease of the polarity of the different oils.  Additional bulk rheology experiments at the scale of oleogels show that gel strength of the network formed by protein aggregates is affected by the polarity of the oil, resulting in weaker gels in more polar oils as a result of larger particle-solvent interaction. Moreover, large deformation rheology shows that protein oleogels exhibit a yielding behavior under large deformation but regenerate its elasticity quickly. These findings are interesting for various applications in foods.

TECLIS product: TRACKER™ automatic drop tensiometer

Key words: Oleogels, protein aggregates, oil polarity, interfacial tension, rheometer

What are the composition and properties of polyglycerol esters used as surfactants ? 

Reference: Characteristics of polyglycerol ester and its different fractions. C. Curschellas; K. Nagy; E. Windhab; H. J. Limbach; Journal of Colloid and Interface Science 393 (2013) 182-191.

The composition and the properties of polyglycerol esters (PGE 55), a commercially available surfactant used in the food industry, are studied and characterized in this article. A first chemical analysis showed the presence of different degrees of esterification components. Then,  a fractioning based on the polarity of these components highlights that the least polar fraction showed the slowest adsorption kinetics, lowest decrease in interfacial tension and similar interfacial dilatational elasticity as the full mixture while the most polar fraction showed the fastest adsorption kinetics, an overall decrease in interfacial tension similar to the full mixture and a significant increase in the interfacial dilatational elastic modulus. These results were obtained thanks to interfacial tension and dilatational rheology measurement with an automatic drop tensiometer (TRACKER™ by TECLIS). Additional drop tensiometry experiments allowed to show that NaCl has a remarkable impact on the interfacial properties of PGE 55 : the surface activity as well as the elastic are considerably increased. However additional work is needed to understand this effect.

TECLIS product: TRACKER™ automatic drop tensiometer with Phase exchange module

Key words: Polyglycerol ester, polarity, interfacial tension, dilatational rheology, shear rheology, fractionation