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IV. Resultados y discusión. Capítulo III 261
initial sugars, 0.325 ± 0.012 g/100 mL ashes and 0.58 g/100 mL fibre. This
lab-made almond milk was richer in lipids than the commercial one (2.2
g/100 mL lipids), probably due to the different extraction method used. Not
only these compositional differences could affect the fermentation process,
as lipid content is seen to play an important role in milk fermentations
(Saint-Eve et al., 2006; Sandoval-Castilla et al., 2004; Trachoo, 2003; Harte
et al., 2002), but also the different heat treatment received.
The sugar content was higher in the commercial almond milk (3.6 g/100
mL) as a consequence of the cane sugar addition. Nevertheless, lab milk was
enriched with glucose and fructose, which increased total sugars percentage
up to 1.6 g/100 mL.
3.2 Proteolytic activity in fermented almond milks
During industrial processes, starter bacteria are repeatedly exposed to
stress conditions, which induce the bacterial proteases synthesis in order to
obtain nutrients for their growth (Aguirre et al., 2008); these proteases,
besides the almond protein hydrolysis, contributed in flavour and texture of
the resulted fermented products.
Table 1 shows the proteolytic activity obtained for each of the
fermented samples, expressed as the difference in absorbance measured at
340 nm between fermented and non-fermented almond milk. The statistical
results showed that the type of almond milk used as a raw material did not
statistically affect (p > 0.05) the proteolytic activity of the different starter
bacteria.