Oxygen permeability and mechanical properties of films from hydrolyzed whey protein

The effects of whey protein hydrolysis on film oxygen permeability (OP) and mechanical properties at several glycerol-plasticizer levels were studied. Both 5.5% and 10% degree of hydrolysis (DH) whey protein isolate (WPI) had significant effect (p less than or equal to 0.05) on film tensile properti es compared to unhydrolyzed WPI. Hydrolyzed WPI required less glycerol to a chieve the same mechanical properties compared to those of unhydrolyzed WPI . Little or no significant difference (p > 0.05) occurred for film OP betwe en unhydrolyzed WPI, 5.5% DH WPI, and 10% DH WPI films at the same glycerol content. Hydrolyzed WPI films of mechanical properties similar to those of WPI films had better oxygen barrier. Therefore, use of hydrolyzed WPI allo wed achievement of desired film flexibility with less glycerol and with sma ller increase in OF.