Cheese whey protein recovery by ultrafiltration through transglutaminase (TG) catalysis whey protein cross-linking

• Ultrafiltration was used to recovery whey protein after cross-linking at various conditions using TG enzyme.
• The ultrafiltration recovery efficiency of the cross-linking protein in whey was increased.
• The membrane fouling was decrease indicated membrane operation time can be extended.
• Find a new way to improve the whey protein ultrafiltration recovery operation.

In whey ultrafiltration (UF) production, two main problems are whey protein recovery and membrane fouling. In this study, membrane coupling protein transglutaminase (TG) catalysis protein cross-linking was investigated under different conditions to find out the best treatment. We found that the optimal conditions for protein recovery involved catalyzing whey protein cross-linking with TG (40 U/g whey proteins) at 40 °C for 60 min at pH 5.0. Under these conditions, the recovery rate was increased 15–20%, lactose rejection rate was decreased by 10%, and relative permeate flux was increase 30–40% compared to the sample without enzyme treatment (control). It was noticeable that the total resistance and cake resistance were decreased after enzyme catalysis. This was mainly due to the increased particle size and decreased zeta potential. Therefore, membrane coupling enzyme catalysis protein cross-linking is a potential means for further use.