Interface rheology of structured food
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Creato da
Mileti, Olga
Cerra, Maria Carmela
Gabriele, Domenico
de Cindio, Bruno
Baldino, Noemi
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Dottorato di Ricerca in Scienze della Vita. Ciclo XXXI; Proteins are widely used to form and to stabilize the interfacial layers in multiphase systems,
due to their surface activity and their ability to give high mechanical resistance to interfacial
layers. In the food industry, animal proteins are largely employed with these functions, but,
because of their tendency to give rise intolerances or, simply, for etic reasons, their use is
becoming more and more limited. Vegetable proteins could be a good alternative to animal
proteins, thanks to their good nutritional profile and complete amino acid profile, but their
interfacial rheological properties are not widely known in order to evaluate their potential
use in food products such as foams and emulsions.
In this PhD work, the interfacial properties of vegetable proteins were studied and the results
analysed by rheological models. Three different systems were investigated A/W interface,
in particular, soy, hemp and brown rice proteins. The rheological analysis was performed in
dilational and shear kinematics, using the pendant drop tensiometer and the interfacial rod
magnetic field rheometer, respectively. The dilational analysis was performed either in static
as well in dynamic condition. The static measurements allow evaluating the saturation
concentration (CMC, critical micellar concentration) and the kinetic phenomena, while the
dynamic measurements help to characterize the viscoelastic film at the interface. In
particular, all the dynamic tests were performed at the CMC concentration, either the
frequency sweep tests (in the linearity region) as well the stress relaxation tests (in the linear
region, but far from equilibrium condition). The kinetic results were interpreted by the Ward-
Torday and Graham and Phillips equations, while the William Watts and the Scott Blair
models were employed for the relaxation experiments.
Finally, vegetable emulsions were obtained and optimized and the use of a polysaccharide
was necessary for stabilising them. The study of the emulsions was carried out with the help
of microscopy and drop diameter distribution. Additionally, measurements of ζ-potential
and flow curve tests were also performed to characterize the system The results showed that the vegetable proteins show comparable mechanical properties and
good surface activity similar to the animal proteins (such as casein or lactoglobulin),
confirming them excellent substitutes in a lot of food systems; Università della CalabriaSoggetto
Rheology; Interfaces; Vegetable proteins
Relazione
ING-IND/24;