Conclusions
Process modification resulted in soy protein isolates with considerably
different functionality. Our results suggest that ethanol
defatting and aqueous extraction of soybeans could be potentially
used as alternatives to hexane. SPIs prepared from these samples
had protein contents of more than 90% and 86%, respectively, with
relatively similar functional properties to those of SPI obtained from
hexane defatted meal. Major differences were a decrease in the
emulsifying activity properties of the SPIs resulting from the alternative
defatting techniques, but with improved emulsion stability and
foaming properties, especially for the aqueous extracted SPIs. The
present study further provides information on how the functional
properties of soy proteins are modified as a result of process variables.
The results demonstrate that slight differences in processing
conditions can induce changes in the extent of denaturation, aggregation,
dissociation, and can remarkably modify functionality.
Soy protein isolates have excellent applications for future product
development by virtue of their functional properties; conditions
used during their preparation can, thus, be optimized to obtain
desirable functional properties.