Investigation on the formulation optimization and characterization of soy protein isolate-based environment-friendly glue

Soy protein isolated was used as the raw material, and response surface methodology was used to optimize the thermal polymerization process conditions of soy protein isolated. The viscosity of soybean protein was determined and analyzed in various conditions. And soy protein isolate-based environment-friendly glue formulations were obtained by orthogonal experiment with the bonding strength index and compared with commercial glue in the total solids content, bonding strength, viscosity, formaldehyde content. The results showed that the optimum parameters of soybean viscosity were concentration of soybean protein 10%, at 85℃for 50 min, the viscosity of soy protein was 7155mPa·s. Glue formulation was SPI 5%, PVA3.32%, sucrose6.64%, glycerin 4.98%, sodium dodecyl sulfate 0.67%, defoamer 3.33%, preservative 0.07% and water 75.99%.Under the condition, glue bonding strength was 870 kPa. The total solids content and viscosity of soy protein isolate glue was greater than the commercial glue but the bonding strength was slightly lower than the commercial glue. The formaldehyde content of soy protein isolated glue and commercial glue were 0 and0.036%, respectively.