Design of equilibrium modified atmosphere packaging for postharvest cabbages preservation based on introducing available active sites into film materials as gas transport channels

This work aims to explore an available avenue to design an equilibrium modified atmosphere packaging (EMAP) by the modification of gas permeability of material. In this work, the introduction of available active sites endowed materials with adjustable gas permeability properties. With varying concentrations of the resulting materials with various gas permeability, the CO2 and O2 gas permeability of the blending films were modified at the range of 3.92 ∼ 17.84 barrier and 0.65 ∼ 3.46 barrier, respectively. On this basis, the films were used as EMAP to preserve postharvest cabbages. The results indicated that each EMAP achieved an equilibrium atmosphere containing 6.8 % ∼ 3.8 % CO2 and 2.1 % ∼ 5.2 % O2 within 15 h and maintained it continuously. In these atmosphere, the respiratory rate of the preserved cabbages was significantly inhibited, thereby delaying the deterioration of their storage quality. As the results, sensory scores of the preserved samples were maximally maintained. Declines of color indexes and texture indexes were obviously inhibited. Chemical variations in chlorophyll content, total phenolics content, total flavonoids content, ascorbic acid and nitrite content were significantly suppressed. The overall findings revealed that this method is suitable and promising to develop EMAP for the postharvest vegetables.

Effects of incorporation with clove (Eugenia caryophyllata) essential oil (CEO) on overall performance of chitosan as active coating

This research is focused on improving performance of chitosan based functional material by introducing active additive. A series of assays revealed incorporation with clove essential oil (CEO) significantly improved the physical, chemical and antimicrobial performance of chitosan. In this work, the prepared chitosan-CEO film (CH-CEO) showed varieties in color parameters, mechanical strength and water vapor permeability. Moreover, chitosan was endowed with significant antioxidant and antimicrobial activities, thereby it was used as protective coatings for fresh-cutting apple tubes at ~1 °C. Results demonstrated the treatment slowed down the quality deterioration process of preserved apple samples, especially for firmness and color. As well, CH-CEO coating reduced microbial counts in the preserved apple samples and inhibited the varieties in the chemical properties. The overall observations revealed that CH-CEO film has remarkable potential as an antioxidant and antimicrobial material, especially as an active coating for fresh-cutting foods during storage.