Laponite®/Ethyl Lauroyl Arginate Complex–Functionalized Silk Peptide/Chitosan Edible Coating for Banana Preservation

Laponite® (LRD) was modified with ethyl lauroyl arginate (LAE) to form complexes, which were subsequently incorporated into solutions of silk peptide (SP) and chitosan (CS) to prepare SP–CS biopolymer composite films by the casting method. Compared with LRD, the LRD/LAE complex demonstrated superior dispersibility within the SP–CS film, thereby improving the compatibility between SP and CS. The mechanical, thermal and antimicrobial properties of the SP–CS film increased while the water vapor permeability (WVP) decreased with the incorporation of the LRD/LAE complex. Remarkably, the SP–CS film containing 2% LRD and 1% LAE complex (SP–CS–C) exhibited the lowest WVP (0.35 g·mm·m−2·h−1·kPa−1) resulted in the highest tensile strength (27.99 MPa) and elongation at break (81.62%). When an edible bananas coating was applied, the weight loss of the SP–CS–C film decreased to 13.92%, and the hardness (176.94 g), titratable acidity (0.15%), and total soluble solids (19.20%) improved. The microbial counts decreased to 3.80 log CFU/g for the colonies and 3.30 log CFU/g for the molds on day 7, whereas they decreased to 5.78 and 4.65 log CFU/g, respectively, in the control group. These results show that the SP–CS–C film extends the banana shelf life during storage at 25 °C and approximately 50% RH for 7 days.