Preparation Of Nano-Packing And Effect On Preservation Quality Of Golden Mushroom And Kiwifruit

Functional nano-particals and preparation technology and formula were screen out for the application of fresh food nano-packing material. The morphological characterization, permeability resistance and antibacterial effect of nanocomposite were conducted. Further researches on the effect of nano-packing on fresh agricultural products’physiology and bio-chemical variation during preservation were investigated. The main research results were as follows:1. A nano-packing material was prepared by blending polyethylene (PE) with nanocomposite masterbatch containing30wt.%of nano-power (35wt.%of nano-silver,40wt.%of nano-titanium dioxide and25wt.%of montmorillonite),56wt.%of PE granule and14wt.%of cross-link reagent KH-570with the mass ratio of PE to nanocomposite masterbatch77:3. After compounds were immingled in uniformity through a twin-screw extruder, and thenthey were blown into films of50μm thickness.2. The morphological characterization, physical properties and antibacterial effect of nanocomposite-based packaging were conducted via scanning electron microscopy, barrier properties test and conidial germination test. The results indicated that homogeneous distribution nanoparticles established significant improvements to the polymers matrix in terms of less water and oxygen transmission rate which was decreased by19.54%,32.86%compared with regular packaging respectively; Longitudinal strength value and inhibited spore germination rate against Botrytis cinerea of nano-packing films were higher than normal films by31.69%and2.34folds. The study would provied the theoretical and practical basis for the application of nano-packing on preservation of fresh agricultural products.3. By taking golden mushroom (Flammulina velutipes) as the research object, nano-packing’s effects on the preservation quality of easy-browning mushroom were investigated. During the15-day storage at4℃, the sensory quality, weight loss, decay rates, browning degree, relative conductivity, soluble solids content, soluble protein and free amino acid parameters of Flammulina velutipes treated with nano-packaging material and regular PE packaging were evaluated. The results indicated that the significant differences were exhibited between the packages with and without nanoparticles on the sensory quality, physiological indexes and main nutritional quality of golden mushroom. Weight loss, rot index, relative conductivity and browning degree of Flammulina velutipes in nano-packaging material were decreased by43.14%,97.13%,29.77%and12.68%compared to regular packaging respectively. Additionally, the soluble solids content, soluble protein and free amino acid content in the Flammulina velutipes under nano-packaging material were also well presented. Nanocomposite-based packaging material greatly improved the preservation quality of golden mushroom compared with regular packaging.4. By taking kiwifruit (Actinidia deliciosa cv.Qinmei) as the research object, nano-packing was tested on the ethylene-mediated effect of ethylene induced maturation of kiwifruit. During refrigerated storage for42d, the organoleptic characteristics, nutritional content and physiological indexes of ethylene treated kiwifruit in nano-packing and normal PE packaging were evaluated until flesh turned to eaten ripen. The results indicated that nano-packing slowed down the ripening process of kiwifruit by indicating weight loss, softening, color difference and soluble solid content were significantly inhibited by22.67%、124.84%、23.46%and14.42%compared with normal packaging. Meanwhile,57.44%lower headspace ethylene concentration,29.44%for malondialdehyde (MDA), lower PPO activity and higher POD activity, likewise, the significant differences were exhibited between the packages with and without nanoparticles on the main nutritional quality (ascorbic acid, total phenols, reducing sugar and titratable acid content) of kiwifruit. nano-packing guarantee a shelf-life longer than that of normal packing. The obtained results suggested that nanocomposite-based films could be new packaging strategies to retard ripening and improve preservation quality of kiwifruit.