Thermomechanical and thermal properties of whey protein, maize prolamin protein (zein), and the laminated whey protein-zein films were studied. The dynamic mechanical (thermal) analysis (DMTA) results showed that the single zein film had higher T-g than single whey protein and zein-whey laminated films. The shift in the T-g values of films from 31.2 degrees C in whey protein film and 88.5 degrees C in the zein film to 82.8 degrees C in the laminated whey protein-zein films may be implied some interaction formation between the two polymers. The small tan 6 peaks were observed at -50 degrees C in zein-glycerol films and at -22.37 degrees C in the whey protein films and can be related to beta-relaxation phenomena or presence of glycerol rich region in polymer matrix. Zein-olive oil and zein-whey protein-olive oil films showed tan 8 peaks corresponded the T-g values at 113.8, and 92.4 degrees C, respectively. Thus, replacing of glycerol with olive oil in film composition increased T-g. A good correspondence was obtained when DSC results were compared with the tan delta peaks in DMTA measurements. DSC thermograms suggested that plasticizers and biopolymers remained a homogeneous material throughout the cooling and heating cycle. The results showed that T-g of zein-glycerol films predicted by Couchman and Karasz equation is very close to value obtained by DSC experiments. (C) 2008 Wiley Periodicals, Inc.