Reversible inhibition of trypsin activity with soybean flour in hide bating process for leather quality improvement

Trypsin is used to remove non-collagenous proteins from cattle hide in leather processing but prone to damage hide surface and reduce leather quality due to its rapid protein hydrolysis action on the hide surface and slow penetration through the whole hide. A novel trypsin bating method was developed using a reversible inhibition of trypsin with high-yield, low-cost and environment-friendly soybean flour (SF). When the mass ratio of trypsin to SF was 1:20, the trypsin activity was decreased by 77 % at a reaction time of 5 min and completely returned in 100 min because of the competitive Kunitz trypsin inhibitor in SF. Bating with trypsin-SF mixture avoided the damage to hide surface caused by trypsin, improved the dispersion uniformity of hide collagen fibers and increased the softness and the mechanical strength of leather. This work exhibits huge potential for improving the leather quality and provides new insights into the soybean application.