Influence of Surfactants on the Rheological Behavior of Starch/Gelatin Gels and Gel‐Emulsions

Abstract

Thixotropic behavior of mixed 8% starch/gelatin gels and gel‐emulsions (8% of the sunflower oil dispersed in the starch/gelatin gel), prepared with the addition of different emulsifiers, by means of the rotational viscometer with coaxial cylinders, has been investigated. Different emulsifiers (Na‐dodecyl sulfate, cetyl alcohol, mono‐ and diglycerides of fatty acids and alkyl polyglycolethers) were applied before (at 40°C) and after (at 96°C) gelatinization of the starch. Thixotropic properties, i.e. the coefficients of thixotropy of gels and emulsions were determined by the thixotropic loop method. Samples were taken in different time intervals (up to 72 h), in order to investigate the ageing effects. Very stable gels and gel emulsions (containing carbohydrate, protein and fatty component), with high aging stability can be obtained.

Microstructure and elastic modulus of phase-separated gelatin–starch hydrogels containing dispersed oil droplets

“…There has been comparatively little research reported on phaseseparated 'oil-in-water-in-water' emulsion gels, with all studies to date focussing on either the modulation of phase-separated gel rheology via integration of a dispersed oil phase (Dakovic, Milosevic, & Sovilj, 1994;Foster, 2007;Foster & Wolf, 2011;Shrinivas et al, 2009) or their evaluation as delivery vehicles by encapsulating oil droplets and lipophilic bioactive components (Kim, Decker, & Mcclements, 2006;Mcclements, Decker, & Weiss, 2007;Matalanis, Lesmes, Decker, & Mcclements, 2010). In the present study, we investigated how the presence of a dispersed oil phase impacted the microstructure and elastic modulus of gelatinestarch phase-separated gels, hence creating oil-in-waterin-water phase-separated emulsion gels.…”

Rheological characterisation of chitosan/sodium lauryl ether sulfate complexes

“…A thixotropic loop was obtained by continually increasing shearing rates γ (s -1 ) from zero (γ = 0) to maximal one (γ max =200 s -1 ), and reversely (after 10 min shearing at γ max ). Obtained thixotropic loops areas were characterized by a coefficient of thixotropy K t (28):…”

Rapid test to record the impact of bakery additives on starch gelatinization: Amylases, hydrocolloids and emulsifiers

“…α-Amylase activity is inversely proportional to the FN, indeed flours with a low FN are characterized by high α-amylase activity, which rapidly hydrolyzes the starch and make the suspension less viscous. Rotational viscometer has also been used to study the impact of enzymes (Sanromán et al, 1996), hydrocolloids (Shi and BeMiller, 2002) or emulsifiers (Dakovic et al, 1994) on the rheological behavior of starch. Graber (1999) studied the effect of several enzymes on rice dough.…”