Soy protein biopolymers cross‐linked with glutaraldehyde

Biopolymers from soy protein isolate (SPI) crosslinked with glutaraldehyde (GA) were prepared. Surface hydrophobicities of SPI‐GA biopolymers and SPI were 4.4 and 11.5, respectively. The solubility profile of SPI was slightly higher than that of SPI‐GA biopolymers. Foaming capacities of SPI‐GA biopolymers (23 mL) were higher than that of SPI (19 mL), but similar to egg white (22 mL). Foaming stabilities of SPI‐GA biopolymers (120 min) were significantly higher than those of SPI (40 min) and egg white (98 min). The emulsifying properties of SPI‐GA biopolymers were lower than those of SPI and bovine serum albumin (P>0.05). Tensile strength (TS) and elongation at break (ETB) of SPI‐GA biopolymer films were significantly higher than those of glycerol‐plasticized soy protein films. TS and ETB of SPI‐GA biopolymer films increased with increasing GA concentrations. GA treatment intensified yellowness of SPI‐GA biopolymer films. SPI‐GA biopolymers may have potential use for biodegradable packaging materials.