Innovative active and intelligent packaging film based on pectin/gelatin biocomposites with zein nanoparticles and anthocyanin: Quality monitoring in mandarin and cucumber

With increasing demand for active and intelligent packaging to extend the shelf life of fresh produce and monitor its freshness, this study focused on developing a nanocomposite film. The film incorporates anthocyanin and bioactive chestnut shell extract-loaded zein nanoparticles, and its applications as coatings and packaging material for mandarin and cucumber fruits were investigated. Extracts derived from waste materials including chestnut shell, cedar tree bark and sweetgum (styrax liquidus) shell, chestnut shell extract-loaded active and intelligent nanocomposite films exhibited excellent properties, including low water vapor permeability (0.325 ± 0.055 g.mm/m².h.kPa), high total phenolic content (77.20 ± 5.64 mg GAE/g dry matter), and strong antioxidant capacity (220.04 ± 2.70 mg Trolox equivalent /100 g dry weight). The film demonstrated sufficient tensile strength (29.35 ± 3.40 MPa) and elongation at break (100.86 ± 2.25 %) for its conversion into a practical packaging material. To evaluate its effectiveness, coating and packaging applications were carried out on mandarin and cucumber fruits, serving as non-climacteric model fresh produce. Coating and packaging significantly (p < 0.05) inhibited the growth of total aerobic mesophilic bacteria and yeast and mold in mandarins, though the effect on yeast and mold in cucumbers was limited. At the end of storage, packaged mandarin and cucumber fruits exhibited the highest total phenolic content, measuring 423.77 ± 17.68 and 96.47 ± 10.52 mg GAE/100 g dry matter, respectively. Coated fruits demonstrated significantly (p < 0.05) higher total phenolic content (382.57 ± 18.32 mg GAE/100 g dry matter for mandarin and 91.52 ± 7.63 mg GAE/100 g dry matter for cucumber) compared to control samples (281.22 ± 10.49 mg GAE/100 g dry matter for mandarin and 69.56 ± 8.99 mg GAE/100 g dry matter for cucumber). Color and textural properties of mandarin fruit were effectively maintained through coating and packaging. However, cucumber fruits, due to their high respiration rate and thin peel structure, did not show the same extent of improvements. The anthocyanin indicator in intelligent packaging exhibited more visible and effective color changes in cucumbers compared to mandarin fruits.