Starch plantain (StP) and serum proteins (SPr) of milk (α-LA, β-and β-LGB LGA) were mixed to produce biofilm by casting method. Solubility in StP/SPr biofilm (32.42%) was higher than biofilm control made with StP (7.2%). Addition of SPr in biofilm, improved mechanical properties, increasing values such as Young's modulus and maximum stress at break, inverse pattern was observed in elongation at break. StP/α-LA biofilms showed a higher increase in melting temperature than that observed in StP/β-LGA and StP/β-LGB. Temperature stability (ΔH) in biofilms was improved by addition of StP. Spectrophotometry studies showed greater length band at 3500 cm–1 in films StP/SPr indicating an increase in -OH groups, which is related to the higher solubility in these biofilms.