Abstract
Dietetic fiber is a compound that, despite its benefits to human health, may be
appropriated to increase the viscosity and other related properties of determined
compounds. Nevertheless, its origin, concentration level and the procedure used to
add it may affect its functionality. In this work an study of the physicochemical an
structural properties of dietetic fiber of different origin (lemon, orange and apple)
was carried out. Obtained results showed a greater insoluble solid content of lemon
and orange fibers, with a high content of fibrous particles in the first one. The apple
fiber showed a greater soluble solid content. These compositional differences
supposed differences in the rheological behaviour of the suspensions prepared with
them, so that lemon ones showed a plastic and thixotropic behaviour at low shear
rates, probably related to the presence of fibrous particles. On the other hand, the
greater viscosities of the suspensions with lemon fiber, especially at low shear
rates, allow us to recommend it for the stabilization of systems from sedimentation
or creaming. Related to the procedure used to prepare the suspensions, this may
allow the maximum solubilization of the soluble compounds of the fiber, in order
to avoid its evolution with time. In this sense, a deep homogenization (about 8000
rpm) must be carried out during long time (15-20 min) or at high temperature (60
ºC). The sensory attributes that most contribute to the definition of the texture of
these suspensions were, by one hand the particles quantity and size and the
granulosity, that were specially detected in the orange fiber and that are related
with the insoluble solids but probably more with its type than with its quality.
These attributes are the most related with the instrumental values of viscosity
obtained at high shear rate. On the other hand, the fluency, consistency and
viscosity were the attributes increases when the fiber content increases, being more
intense its perception for the lemon fiber.