The results for all parameters were evaluated on two points
of view: (1) comparative analysis of the TCA-soluble proteins,
functional properties and stimulation of the bacteria growth
in the media supplemented with hydrolyzed and non-
hydrolyzed proteins in respective runs of the statistical
mixture design to verify the changes caused by the enzymatic
hydrolysis and (2) evaluation of the synergistic or antagonis-
tic interactions of hydrolyzed, non-hydrolyzed proteins and
their mixtures on the TCA-soluble proteins, functional prop-
erties and stimulation of the bacteria growth.
inactivation. The mixtures were centrifuged at 17,000 g at
5 1C for 20 min and the supernatants containing peptides were
collected and freeze-dried for the determination of the TCA-
soluble proteins, functional properties and in the growth
promotion of the bacteria cultures.
The interactions amongst the three substrates in the TCA-
soluble proteins, functional properties and bacteria growth
(%) were studied in the seven assays using a simplex centroid
mixture design (Table 1). The size of peptides is known to be a
significant factor in the overall bioactivities and functional
properties of protein hydrolysates. Assessment of proteolysis
levels is often achieved by global quantification of the pep-
tides soluble at certain concentrations of trichloroacetic acid
(TCA). This parameter has been used as an indication for the
amount of small-sized peptides in the protein hydrolysates
and has a positive correlation with the degree of hydrolysis
(DH) (Zhou et al., 2012). The TCA-soluble proteins of the
different protein sources showed significant changes after
the enzymatic hydrolysis. For SPI (run 2), the TCA-soluble
proteins ranged from 30.70 mg (intact protein) to 62.47 mg
(protein hydrolysates), resulting in an increase of 103.5%. For
BWP (run 2) and EWP (run 3), the observed increases were
52.2 and 288.5%, respectively, as compared to intact proteins
(Table 1).
Selective enzymatic hydrolysis under controlled condi-
tions has been used to improve the solubility, heat stability,
emulsifying and foaming properties of proteins. In our study,
it was observed that the enzymatic hydrolysis increased
protein solubility, except for EWP and the mixtures contain-
ing it (Table 1). High solubility is an important property to
improve functional characteristics that depend on an