Fabrication of hydrophobic and high-strength packaging films based on the esterification modification of galactomannan.

There is an increasing interest in substituting current packaging films with biologically-derived films without compromising mechanical properties and hydrophobicity. In this work, the esterified galactomannan (E-GM) films with good hydrophobicity, excellent oxygen barrier performance and high tensile mechanical strength were synthesized using anhydride esterification method prior to film formation. The hydrophobicity, mechanical properties, barrier properties, thermal stability and ultraviolet absorption of the prepared films were determined to fully investigate the features of galactomannan-based films. The results indicated that GM films can be successfully obtained by esterification. Compared to neat GM film, E-GM-1.5 film (acetic anhydride to GM of 1.5:1) achieved the highest degree of esterification (0.05), hydrophobicity (107°) and mechanical strength (92.0 MPa). In addition, the esterified GM films had lower toxicity for macrophages cells. The prepared E-GM films may provide more opportunities for further advancement and applications in the development of food packaging from natural resources.