UNIVERSITAT POLITÈCNICA DE VALÈNCIA Desarrollo ... - RiuNet

IV. Resultados y discusión. Capítulo II 225
sources in the form of mono- or disaccharides and inulin was not consumed.
Nevertheless, Corcoran et al. (2005) observed that GG was able to grow in a
medium until glucose levels reached 0.018 g/100 mL. Therefore, not having
sufficient glucose in hazelnut milk after 7 storage days, GG might start to
hydrolyse this prebiotic so as to obtain the energy required to grow, thus
generating higher amounts of inulin derivatives. This assumption was
consistent with the high survivals of GG observed until the last day controlled
(Table 3). Therefore, the hazelnut milk formulation is highly suitable for
developing new non-dairy probiotic products.
To sum up, both the GG survivals and the sugar content results have
reinforced the belief that inulin can enhance probiotic survivals (Capela,
Hay and Shah, 2006; Frank, 2002, Kolida et al., 2002).
3.3.3 Physical properties
Rheological behaviour plays a key role in the perceptions of a product’s
texture and sensory features. Figure 4 shows the up-flow curves obtained in
the different samples. The flow curve of samples stored for 28 days was not
shown since product phase separation occurred at this time (Figure 5). Both
fermented and non-fermented hazelnut milks were shear thinning (n < 1) and
time-dependent (hysteresis was observed), as are a large number of
hydrocolloidal dispersions (Marcotte, Taherian-Hoshahili and Ramaswamy,
2001). Table 4 summarises the rheological parameters obtained from fitting
Eq. 1 by means of a non-linear procedure, as well the thixotropic areas. The
apparent viscosities of samples at a shear rate of 50 s -1 were also shown.