This study sheds light on the potential of microbial transglutaminase (mTG)-mediated modification to enhance the properties of heat-denatured whey protein-based films. In this study, we investigated the biochemical modification of heat-denatured whey proteins (WPs) using mTG, an enzyme known for the ability of crosslinking reactions. By introducing ε-(γ-glutamyl)-lysine crosslinks via an acyl transfer reaction, mTG enhances the properties of bio-based materials. In this research, heated WPs were demonstrated to effectively serve as mTG substrates. The preparation of crosslinked bio-based material was achieved using a casting method under alkaline conditions (pH 12) in the presence of glycerol (40% w/w), which was added as a plasticizer to the film-forming solution (FFS). A comprehensive characterization of the FFSs and the resulting materials was carried out. The FFSs were quite stable as evidenced by Zeta potential values that were always around 30/40 mV regardless of the presence of the enzyme. The enzymatic modification increased the elongation at break of the materials from 10.4 ± 4.9 MPa to 27.6 ± 8.9 MPa, while decreasing both tensile strength and Young’s modulus, thereby making the resulting material more extensible. On the other hand, the enzyme affected both the CO₂ and O₂ barrier properties, with permeability values for these gases being 0.90 cm³ mm m⁻² day⁻¹ kPa⁻ and 0.26 cm³ mm m⁻² day⁻¹ kPa, respectively, when the films were cast without the enzymatic treatment, but decreasing to 0.14 ± 0.02 cm³ mm m⁻² day⁻¹ kPa (CO₂) and 0.02 ± 0.02 cm³ mm m⁻² day⁻¹ kPa (O₂) in the presence of 24 U/g of mTG. These novel materials, prepared from renewable sources, could potentially be used in the food packaging field to replace/reduce the highly pollutant petroleum-based ones.

Title

Coatings

Publisher

MDPI

Publisher Country

Switzerland

Publication Type

Both (Printed and Online)

Volume

15

Year

2025

Pages

66