Enhanced postharvest protection of cherry tomatoes by a fully bio-based quasi-mixed matrix membrane (quasi-MMM) with dual-mechanism integration of organic filler.

Conventional mixed matrix membranes (MMMs) are organic-inorganic hybrids. Following analogous structural logic, we develop a fully bio-based quasi-mixed matrix membrane (Quasi-MMM) using ferulic acid (FA) as a dual-functional organic filler in a chitosan-caseinate matrix. FA establishes covalent ester/amide linkages and an extensive hydrogen-bonding network with the biopolymer continuous phase, emulating the matrix-filler synergy of classical MMMs while imparting sustained antioxidant activity. The resulting dense membrane exhibits robust mechanical strength (∼ 55 MPa), tunable barrier properties, enhanced hydrophilicity and anomalously slow FA release (∼50% over 25 d) governed by non-Fickian transport. When coated on cherry tomatoes and stored at 4 °C for 25 d, the Quasi-MMM reduces malondialdehyde accumulation by >35%, suppresses microbial growth by >2 log CFU·g-1, and maintains firmness, ascorbic acid, and total phenolics near initial levels. This Quasi-MMM concept offers a viable green strategy for postharvest preservation by integrating structural reinforcement and continuous bioactive protection within a single, entirely organic platform.