Functional Pectin Film Modified by Chestnut Burr Polyphenols/Cinnamaldehyde Nano Emulsion via Microfluidization for Fruit Preservation

Pectin-based biodegradable films face limitations in fruit packaging applications due to their inherent brittleness, low bioactivity, and strong hygroscopicity. To overcome these limitations, polyphenol-cinnamaldehyde nanoemulsion (PCNE) was prepared by isolating polyphenols from local chestnut burrs, and microfluidic technology was employed to enhance PCNE uniformity. Pectin films modified with PCNE demonstrated simultaneous improvements in both physical properties and functionality. The Pectin-PCNE composite film presents a higher water contact angle (76.48°), tensile strength (42.22 MPa), elongation at break (13.41%), lower water vapor permeability (0.90 × 10^-12 g/cm·s·Pa), and oxygen permeability (0.85 × 10^-15 cm³(STP)·cm/(cm²·s·Pa)) compared with that of the pure pectin film. The PCNE-pectin composite film shows antiultraviolet ability to block the UVC (200-275 nm), UVB (275-320 nm), and up to 95% of UVA (320-400 nm), as well as antioxidant (DPPH inhibition rate 95.6% and T-AOC 58.33 μmol/g), and antibacterial properties. The combined functional properties of these films contribute to a marked extension of strawberry shelf life in fruit packaging applications. PCNE is an innovative approach to improve the bioactivity, mechanical properties, and hydrophobicity of pectin films. The pectin-PCNE composite film presents great potential in fruit packaging as a substitute for petrochemical plastics.