Characterization of chitosan/zein composite film combined with tea polyphenol and its application on postharvest quality improvement of mushroom (Lyophyllum decastes Sing.)

In this study, chitosan/zein composite film combined with tea polyphenol was fabricated, and the effect of tea polyphenol on the structure and physical properties of chitosan/zein film was investigated. Low-field nuclear magnetic resonance spectroscopy indicated that the distribution and content of water molecules in chitosan/zein film were changed with the addition of tea polyphenol. The results of fluorescence measurement and secondary structure analysis proved the enhanced physical and structural properties of tea polyphenol composite film. And the film showed favorable stretching resistance and flexibility. Furthermore, the effect of composite film on quality and physiological indexes of mushroom (Lyophyllum decastes Sing.) stored at 4 °C for 15 d were systematically evaluated. The results indicated that the tea polyphenol composite film showed the effectiveness of maintaining color, texture as well as integrity of cell membrane evidenced by relatively lower membrane permeability and malondialdehyde content of mushrooms. Besides, weight loss and respiration rate were efficiently retarded. In comparison with control and chitosan/zein film, the tea polyphenol composite film inhibited the activity of polyphenol oxidase and peroxidase, while enhanced the activity of antioxidant enzymes (superoxide dismutase and catalase). In a word, the chitosan/zein composite film incorporated with tea polyphenol showed the potential as an effective technology for maintaining the postharvest quality of mushroom (Lyophyllum decastes Sing.).