The main factors that lead to fruit spoilage are ethylene and microbial contamination. The majority of existing studies focus on single regulation tools for extending fruit shelf life, such as controlling ethylene concentration or inhibiting microbial contamination. The objective of this study was to fabricate zein–natamycin (Z-Nt) films that utilize the synergistic effect of zein and natamycin to extend the shelf life of fruits in terms of ethylene adsorption and microbial inhibition. The mechanical properties, contact angle, water vapor permeability (WVP), oxygen permeability (OP), ethylene adsorption efficiency, antimicrobial properties, and fruit preservation tests were used to characterize the performances of the Z-Nt films. As the natamycin content increased, the films presented an increase in contact angle and a decrease in WVP, indicating an increase in the hydrophobicity of the films. Furthermore, the natamycin content of the films is inversely proportional to OP and positively proportional to ethylene adsorption efficiency. The antimicrobial properties of the films were evaluated against Geotrichum candidum strain and Wickerhamomyces anomalus isolate. Inhibition of mold growth was observed for all natamycin-containing films. Thus, in the case of bananas, the film has a significant mitigating effect on the browning rate, weight loss rate, and hardness of bananas within a certain storage period. It can therefore be concluded that the film, as a bio-based material, has good application value for extending the shelf life of fruits and improving their storage quality.

Ethylene scavengers exhibit considerably high potential for their application in prolonging the shelf-life of fruits, but their application has been hindered owing to food safety and environmental issues. Thus, in this study, we fabricated a bio-based nanofiber film composed of zein, Artemisia sphaerocephala Krasch. gum (ASKG), and chitosan (CS) via electrospinning. The addition of ASKG and CS increased the viscosity and surface tension of zein precursor solutions and consequently enhanced their spinnability. Electrostatic co-assembly between the protein and polysaccharides led to the formation core-shell nanofibers (Z@A-CS nanofibers), which effectively enhanced their ethylene removal efficiency, mechanical properties, and hydrophobicity. Furthermore, bananas incubated with the Z@A-CS nanofiber films for 10 days exhibited a lower browning rate, higher hardness, and prolonged shelf-life compared to those incubated without a film. Based on these results, we deduce that the strong interactions between the numerous active functional groups of zein and ethylene and the large specific surface area of the nanofibers led to the development of highly efficient, environmentally friendly, and economical ethylene scavenger films, which exhibit a high potential in fruit preservation.

The aim of the study was to prepare depolymerized zein (D-zein) films for fruit packaging. High-intensity ultrasound (HIU) treatment was employed to stretch the chemical structure of zein protein, and improve the ethylene adsorption efficiency of D-zein films. The study of circular dichroism spectra, fluorescence spectra, particle size, zeta-potential, and total sulfhydryl group content revealed that the depolymerized zein had stretched structure via a moderate HIU treatment (400 W, 15 min). The structural, mechanical, barrier properties, ethylene adsorption efficiency, and application were used to analyze the performance of the D-zein films. In all treatment groups, bananas coated with the D-zein-15 film exhibited favorable browning rate, weight loss rate, flesh hardness, and sensory properties during storage at 25 degrees C for 10 d. The results indicated that depolymerized zein films could improve the ethylene adsorption efficiency and effectively prolong the shelf life of bananas.

【Objective】Ethylene is an important plant hormone that has a key influence on the quality and shelf life of fruit.In this study,zein was modified to transform into a stretched structure and consequently expose its internal active functional groups by the high-field intensity ultrasound treatment （HIU）.Numerous functional groups （-SH） exposed in modified zein film could rapidly react with ethylene via a click reaction,resulting in an extended shelf life of the fruit.【Method】The 5 g zein was dissolved in acetic acid-DI water （4:1） solution.The zein solutions were sonicated for 0,5,15,and 30 min at an ultrasonic power of 400 W and dried in a drying oven at 40℃for 24 h to obtain the zein-0 film,zein-5 film,zein-15 film,and zein-30 film.The structures of zein before and after HIU treatment were analyzed by circular dichroism spectroscopy,endogenous fluorescence,particle size potentiometer,and scanning electron microscope.The mechanical and ethylene adsorption properties of zein-based films were characterized by the texture analyzer and the VOC detector.Bananas were used as the climacteric fruit samples to investigate the effectiveness of the zein films as ethylene scavengers.The ultrasonic treated zein film and banana samples were placed in the same plastic sealing bag and then stored at room temperature for 10 d.The performance for extending shelf life was evaluating by browning rate,the flesh hardness,and the weight loss rate of bananas.【Result】The HIU treatment （20 kHz,400 W,15 min） could effectively stretch the structure of zein.The particle size of the zein and the content of the α-helix were decreased to 1 013.3±6.9 nm,and 45.86%,respectively,and the content of the β-sheet increased to 12.20%.Compared with the zein-0 film,the ethylene adsorption capacity and oxygen resistance of the zein-15 film were increased by 9.486 mg·m -3 ·h -1 and 0.75×10 -16 kg·m·m -2 ·s -1 ·Pa -1 ,respectively.The results including the browning rate,the flesh hardness,and the weight loss rate of bananas indicated that the zein-15 film could effectively extend the shelf-life of bananas.【Conclusion】The HIU treatment （20 kHz,400 W,15 min） could effectively induce to stretch the zein structure and expose more functional groups,resulting in an improved ethylene adsorption performance of zein.The zein-15film presented a better ethylene adsorption capacity,oxygen permeability,and mechanical property,leading to an extended shelf life of bananas and its life as the ethylene scavenger.