Cold-set gelation of high pressure-treated soybean proteins

The ability of soybean proteins to form cold-set gels, using high pressure (HP) processing as denaturing agent and calcium incorporation was evaluated. Different protein preparations were assayed: soybean protein isolate (SPI), a β-conglycinin enriched fraction (7SEF) and a glycinin enriched fraction (11SEF). 7SEF formed aggregated gels with low water holding capacity whereas 11SEF did not form self-standing gels. SPI formed the better gels: ordered and with high water holding capacity. SPI gels were relatively soft and their visual aspect, rheological and texture properties, and water holding capacity depended on HP level (400–600 MPa), CaCl2 concentration (0.015–0.020 mol L−1) and protein concentration (85–95 g L−1), thus gels with different characteristics may be obtained. The gels comprised a three dimensional network stabilized by non-covalent interactions with spaces filled of proteins in aqueous solution. The results indicate that it is possible to use HP and subsequent calcium incorporation to form self-standing cold-set gels from soybean proteins. These gels may be of interest to incorporate heat-labile compounds or probiotics during the gelation step.