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IV. Resultados y discusión. Capítulo II 183
Table 7. Mean values (and standard deviation) of yield stress ( y ), flow
behaviour index (n) and consistency index (K) in both non-fermented (AM)
and fermented almond milks (FAM) throughout storage time (d). The nonlinear
correlation coefficient R 2 is also included. The apparent viscosity ()
was calculated at a shear rate of 50 s -1 . The hysteresis area quantified in flow
curves is also presented.
Sample y Pa) n
K
(Pa·s n )
R 2
·
Pa·s)
Hysteresis
A (Pa/s))
AM 0.317 (0.002) 0.77 (0.07) 0.0239 (0.0014) 1 9.3 (1.4) 108 (24)
FAM 1d 0.300 (0.016) 0.78 (0.05) 0.0247 (0.0011) 0.999 10.04 (1.15) 144 (17)
FAM 7d 0.314 (0.010) 0.769 (0.013) 0.0269 (0.0005) 1 10.9 (0.5) 170 (10)
FAM 14d 0.30 (0.03) 0.749 (0.014) 0.0315 (0.0007) 0.999 11.8 (0.7) 155 (27)
FAM 21d 0.35 (0.02) 0.84 (0.02) 0.0185 (0.0005) 1 9.8 (0.5) 147 (12)
FAM 28d 0.328 (0.014) 0.77 (0.06) 0.0291 (0.0018) 1 11.5 (1.8) 183 (28)
Results showed that the inner structure of the almond milk were not
significantly (p > 0.05) modified due to either fermentation procedure or
storage time at 4 ºC.
Both the apparent viscosity as well as the thixotropic character of the
samples increased slightly after the fermentation step (p < 0.05). Figure 3
shows the up flow curves of the different samples and Table 7 shows the
values of the hysteresis area which reflects the thixotropic nature of the
products. This character increased after fermentation in line with the
formation of a weak gel structure, as commented on above. L. reuteri is able
to synthesise exopolysaccharides and, thus, it might also contribute to the