Abstract:

Effect of transglutaminase (TGase) reaction time on the properties of TGase-modified soy protein isolate (SPI) films before casting was studied. Moderate TGase reaction of film-forming solution (≤ 60 min) before casting facilitated the improvement of mechanical properties of SPI films, especially the tension strength (TS) value. However, TGase reaction time should not be excessively extended, because precasting TGase reaction could result in the aggregation of SPI components and decrease of soluble protein content. When TGase was used to modify SPI films, on the one hand, TGase reaction could induce the cross-linking of protein; on the other hand, excessive cross-linking could lead to the precipitation of protein. Therefore, appropriate reaction time for inhibiting aggregation induced by TGase during the cross-linking of protein is very important for TGase-modified SPI film.

Key words: transglutaminase, protein film, modification