Structural Characterization and Properties of Pullulan/Curdlan Blend Films and the Coating for Cherry Tomato Preservation

Fruits and vegetables (F&V) are prone to moisture loss and deterioration at postharvest. The strategy of a composite coating based on a single chain-triple helix network was applied to inhibit water escape and respiration of F&V. In this study, pullulan (PUL) with a high oxygen barrier was incorporated with the hydrophobic curdlan (CUD) to prepare the PC solutions and films. The results indicated that the linear PUL molecules were entangled with the CUD triple-helix micelle network, forming a continuous, dense three-dimensional network based on hydrogen bonds, and showing good biocompatibility. The addition of CUD enhanced the surface roughness of PC films, and significantly improved the elongation at break by 89%, hydrophobicity, water vapor and oxygen barrier, and thermal stability. Overall, the P 7 C 3 coating was selected for the cherry tomato preservation, significantly delaying weight loss by 2.5% and ascorbic acid decline by 16.8%, maintaining firmness, total solids, and acid content. The coating significantly inhibited respiratory intensity and sustained the sensory attributes (appearance, texture, taste, and smell) of cherry tomatoes at a high level, which suggested that the P 7 C 3 coating can effectively extend the shelf life of cherry tomatoes. This work would provide a reference for the application of pullulan and curdlan complex in F&V preservation and show a good prospect.